Diagnostic Radiology Notes

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Introduction to pathology CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Introduction to pathology using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic INTRODUCTION TO PATHOLOGY Pathological terminologies (100+ terms) Terms cont. EVOLUTION OF PATHOLOGY PATHOLOGY During this era Papanicolaou in 1930s developed the use of exfoliative cytology for early detection of cervical cancer. Infarction= cellular/tissue death as a result of ischemia/hypoxia Era of gross pathology (AD 1500 to 1800). SUBDIVISIONS OF PATHOLOGY ……. DISEASE DEVELOPMENT ENVIRONMENTAL FACTORS Dietary excess can the cause of many systemic diseases such as cardiac diseases. Hypersensitivity to various substances can lead to alarming shock-like conditions- anaphylaxis. The blood group Duffy negative confers resistance to infection by Plasmodium vivax. PATHOGENESIS Functional derangement and clinical importance CLASSIFICATIONS OF DISEASES Basing on body response disease can be classified into 4 categories namely :- 3) Degenerative = disease due to aging GENERAL PATHOLOGY INTRODUCTION TO PATHOLOGY By the end of this session, students are expected to be able to: Define pathology Understand evolution of pathology Identify subdivisions of pathology Explain disease development Classify categories of diseases Explain cell injury and cell death Pathological terminologies (100+ terms) Pathogenesis = course of disease = start–> end or terminal stage Necrosis = Irreversible abnormal cell death Apoptosis = programmed cell death Aetiology = cause of disease Ischemia= decreased blood flow to body tissue Hypoxia/hypoxemia= low oxygen content in blood Oxidative stress= imbalance between free radicals and antioxidants in the body Terms cont. Hypoxia= low oxygen supply in bodily tissue ROS= Reactive oxygen species are derivatives of oxygen that result from aerobic respiration eg peroxides, superoxide, hydroxyl radical OR Free radicals= oxygen containing molecules with uneven number of electrons (unstable) Antioxidant= any chemical substance that protects a cell from the damage caused by free radicals eg vitamins (A,C,E & K) , Uric acid, Glutathione, Enzymes ( Catalase) Lesion= an area of abnormal tissue FREE RADICALS V ANTIOXIDANTS EVOLUTION OF PATHOLOGY Evolution of Pathology began with the following concepts from different era : Religious and superstitious beliefs to rational approach (Antiquity to AD 1500). The earliest concepts of disease were the religious and superstitious beliefs that affliction or disease was the outcome of curse or evil eye of spirits. The real practice of medicine began in the 460 to 377 BC (Before Christ). Hippocrates introduced ethical concepts in the practice of medicine and admired/respected by the medical profession by taking Hippocratic oaths at the time of entry into practice of medicine. PATHOLOGY The word pathology is derived from Greek words Pathos=suffering and logos= the study Definitions: It is a branch of medicine which deals with the study of the nature (aetiology) and the course (mechanisms) of disease. It is a scientific study of structure and function of the body in disease. During this era Papanicolaou in 1930s developed the use of exfoliative cytology for early detection of cervical cancer. Era of modern pathology (1960s to dawn of 21st century) The major advances in molecular biology in the field of diagnosis and treatment of genetic disorders, immunology and in cancer. These includes:- The description of the structure of DNA Identification of chromosomes and their numbers Recombinant DNA technique Mammalian cloning Infarction= cellular/tissue death as a result of ischemia/hypoxia Inflammation= local response of vascularized tissue to noxious stimuli that causes cellular injury Inflammatory mediators= chemical substances released by cells in response to stimuli causing inflammation [proteins , peptides, glycoprotein ,cytokines ,prostaglandins(Histamine, ] Era of gross pathology (AD 1500 to 1800). In this era the discovery of science in diagnosis involved studies by dissection of human body, autopsy, and the use of microscope in examining the diseased tissues. Era of technology development and cellular pathology (AD 1800 to 1950s). This era the technology of microscopy was advanced to involve, different staining methods or techniques, the use of electron microscope to examine and view ultra structure of the cell and its organelles SUBDIVISIONS OF PATHOLOGY (1)Human pathology is the largest branch of pathology It is conventionally divided into (a)General pathology Which deals with general principles of disease i.e. is concerned with the basic reaction of cells and tissue to abnormal stimuli that underlies all diseases (b)Systemic pathology Includes study of diseases pertaining to the specific organs and body systems. This examine the specific responses of specialized organs and tissue to more or less well defined stimuli (2) Histopathology used synonymously with anatomic pathology (pathologic) anatomy, or morbid anatomy, is the classic method of study and still the most useful one which has stood the test of time. ……. Histopathology is divided into:- (a) Surgical pathology which deals with study of tissues removed from the living body. (b) Forensic pathology and autopsy work includes the study of organs and tissues removed at post-mortem. (3) Cytopathology includes study of cells shade off from lesions (exfoliative cytology and fine needle aspiration cytology of superficial and deep seated lesions for diagnosis). DISEASE DEVELOPMENT This is loss of ease of body Any harmful deviation from the normal structural or functional state of an organism. It is the opposite of health, what is not healthy is diseased The four aspects of a disease process that form the core of pathology are Its cause or aetiology The mechanisms of its development, pathogenesis The structural alterations induced in the cells and organs of the body, morphologic changes The functional consequences of the morphologic changes, clinical significance Introduction to pathology Knowledge or discovery of the primary cause remains the backbone on which a diagnosis can be made, a disease understood or a treatment developed There are two major classes of aetiologic factors o Intrinsic or genetic o Acquired/Environmental factor Genetic factors are clearly involved in some of the common environmentally induced maladies, such as cancers and atherosclerosis The environment may also have profound influences on certain genetic diseases ENVIRONMENTAL FACTORS Are many and are classified as follows : Physical agents, among these are trauma,

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Organs In Different Body Cavity CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Organs In Different Body Cavity using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Body Cavity Main Body Cavities The Ventral Body Cavities Organs-(Abdominal-Pelvic Cavity) …. Male reproductive organs (prostate, part of ductus deferens). Thoracic Cavity and its Divisions The Mediastinum Regions(subdivision) of mediastinum The middle mediastinum The superior mediastinum The anterior mediastinum Peritoneum and Peritoneal Cavity CT ORGANS IN DIFFERENT BODY CAVITIES Body Cavity Body cavities: spaces within the body that help protect, separate and support internal organs. Body cavity is any fluid filled space in a multicellular organism. Main Body Cavities The two major cavities of the body are The dorsal cavity The ventral body cavities. The Dorsal Cavity The dorsal body cavity is located near the posterior surface of the body and has two main subdivisions The vertebral canal that contains the spinal cord The cranial cavity that contains the brain The Ventral Body Cavities The ventral body cavity is located near the anterior surface of the body and has two subdivisions The thoracic cavity The abdomino-pelvic cavity The abdomino-pelvic cavity, which is separated by the diaphragm consists of two continuous cavities -The abdominal cavity -The pelvic cavity Organs-(Abdominal-Pelvic Cavity) Abdominal cavity contains Stomach Liver Gallbladder Pancreas Spleen small intestine Kidneys Appendix part of the large intestine. …. The pelvic cavity contains Part of the large intestine Rectum Urinary bladder Female reproductive organs (ovaries, uterine tubes, uterus, vagina) Male reproductive organs (prostate, part of ductus deferens). It is important to note that the testes and penis are not located in the ventral body cavity but are outside the body wall. Thoracic Cavity and its Divisions Thoracic Cavity: Space enclosed by the ribs, sternum, and vertebral column The thoracic cavity is separated from the abdominal cavity by the diaphragm. This cavity contains three small cavities (potential spaces). The pericardial cavity (peri _around; cardia _ heart). Two pleural cavities (pleura _ side or rib). The pericardial cavity surrounds the heart, and each pleural cavity contains a lung. The Mediastinum A broad central partition that separates the two laterally placed pleural cavities. Extends from the sternum to the bodies of the vertebrae and from the superior thoracic aperture to the diaphragm. The organs located in the mediastinum are the heart, thymus gland, oesophagus, trachea and bronchi. The pleural cavities are located on either side of the mediastinum Regions(subdivision) of mediastinum The middle mediastinum The superior mediastinum The anterior mediastinum The posterior mediastinum The middle mediastinum Centrally located in the thoracic cavity. Major Structures found heart, origins of the great vessels, various nerves smaller vessels. The superior mediastinum The superior mediastinum is posterior to the manubrium of the sternum and anterior to the bodies of the first four thoracic vertebrae. The superior mediastinum is continuous with the neck superiorly and with the inferior mediastinum inferiorly. The Major Structures found include: Thymus Right and left brachiocephalic veins Left superior intercostal vein Superior vena cava Arch of the aorta with its three large branches …. Trachea Esophagus Phrenic nerves Vagus nerves Left recurrent laryngeal branch of the left vagus nerve Thoracic duct Other small nerves, blood vessels, and lymphatics The anterior mediastinum Posterior to the body of the sternum Anterior to the pericardial sac. The posterior mediastinum Posterior to the pericardial sac and diaphragm Anterior to the bodies of the mid and lower thoracic vertebrae. Major structures in the posterior mediastinum Esophagus and its associated nerve plexus Thoracic aorta and its branches Azygous system of veins Thoracic duct and associated lymph nodes Sympathetic trunks Thoracic splanchnic nerves Peritoneum and Peritoneal Cavity The peritoneum is the largest serous membrane in the body The abdominal cavity is lined by peritoneum, which consists of an epithelial-like single layer of cells (the mesothelium) together with a supportive layer of connective tissue. Two layers Parietal peritoneum lines the abdominal wall. Visceral peritoneum covers suspended organs The peritoneal cavity is a potential space between the parietal peritoneum Contains a small amount of serous fluid CT Abdominal viscera are either intraperitoneal or retroperitoneal Intraperitoneal structures are suspended from the abdominal wall by mesenteries Stomach Liver Gallbladder Spleen small intestine …. Appendix large intestine Rectum Urinary bladder Female reproductive organs (ovaries, uterine tubes, uterus, vagina) Male reproductive organs (prostate, part of ductus deferens). CT Structures that are not suspended in the abdominal cavity by a mesentery and that lie between the parietal peritoneum and abdominal wall are retroperitoneal in position includes; The kidneys Ureters Pancreas Great vessels ( aorta and venna cava) ← PREVIOUS TOPICNEXT TOPIC →VIEW ALL MODULE NOTESVIEW SEMESTER NOTESVIEW ALL LEVEL NOTESALL DIAGNOSTIC RADIOLOGY NOTES Need These Notes as PDF? 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DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Structure and Functions of Epithelial Tissues CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Structure and Functions of Epithelial Tissues using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic EPITHELIAL TISSUE Structure of Epithelial Tissues It also forms all glands including endocrine and exocrine glands Classification of Epithelial Tissues Simple Epithelium Simple Cuboidal Epithelium Stratified Epithelia Stratified squamous epithelium Non keratinized stratified epithelium Transitional Epithelia General Functions of Epithelial Tissues General Functions of Epithelial Tissue Secretion summary assignment reference Structure and Functions of Epithelial Tissues EPITHELIAL TISSUE What is epithelial tissue? EPITHELIAL TISSUE Epithelial tissues are linings of the various passages inside the body. Structure of Epithelial Tissues General Structure of Epithelial Tissues Epithelium is a group of closely associated cells with scanty intercellular materials that cover external and internal surfaces of the body They form the covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands Epithelial tissues are widely spread throughout the body The cells in epithelial tissue are tightly packed together with no intercellular material between the cells or very little intercellular materials It also forms all glands including endocrine and exocrine glands The cells are attached to the underlying connective tissue known as the basement membrane The basement membrane is a connective tissue structure where the epithelial cells are attached Cells of epithelial tissue appear in different shapes and structure These differences reflect the functions of the epithelium Classification of Epithelial Tissues what are the classes of epithelial tissue? Classification of Epithelial Tissues Classification according to the cell shape Squamous epithelia:cells are flat cells with an irregular flattened shape (fish-scale appearance) Cuboidal eithelia:cells have a shape similar to a cube, meaning its width is the same size as its height Columnar epithelia: cells are taller than they are wide Classification based on number of cell layers (Stratification) Simple epithelia Stratified epithelia Pseudostratified epithelia Transitional epithelia Simple Epithelium Cells are organized in a single layer and therefore all cells are attached to the basement membrane Because the shapes of the cells include possible function, they are found in different organs depending on their function: There are three types of simple epithelium: Simple squamous epithelium, Simple cuboidal epithelium, Simple columnar epithelium Simple Squamous Epithelium All Squamous cells are flat cells with an irregular flattened shape It is a one-cell layer of simple squamous epithelium Forms a thin membrane and therefore it is found in places where exchange of material from one compartment to the other occurs. Squamous cells can be found in the heart, blood vessels, lymph vessels and alveoli of the lung. They allow free diffusion Simple Cuboidal Epithelium This consists of cube-shaped cells fitting closely together lying on a basement membrane. Forms secretory cells, lining of the small ducts of the glands and it covers the outer surfaces of organs such as the ovaries and in the kidney tubules Are actively involved in secretion, absorption and excretion Simple Columnar Epithelium This is formed by a single layer of cells, rectangular in shape lying on a basement membrane. It is found lining the organs of the alimentary tract. Consists of mixture of cells, some absorb the products of digestion and others secrete mucus. Stratified Epithelia Consists of several layers of cells of various shapes The superficial layers grow up from below Basement membranes are usually absent The main function of compound epithelium is to protect underlying structures There are two types: Stratified and transitional Stratified squamous epithelium Consists of several layers of cells of different shapes The cells are arranged into superficial, intermediate and basal (deep) layers In the deepest layers the cells are mainly columnar and, as they grow towards the surface, they become flattened. It is the main protective epithelium of the body external surface for example in the skin it forms the epidermis,some parts of tongue, hard palate There are two types: Non keratinized stratified epithelium and Keratinized stratified epithelium Keratinized stratified epithelium Refers to cells that has become hardened and died. The cells have a tough fibrous protein called keratin that helps protect the skin and underlying tissues from heat, microbes and chemicals. It is found on dry surfaces that are subject to wear and tear such as skin, hair and nails. Non keratinized stratified epithelium Does not contain keratin and consists of cells which are not dead It is found on wet surfaces that may be subjected to wear and tear but are protected from drying, for example conjunctiva of the eyes, and lining of the mouth, pharynx, the oesophagus and vagina. It provides mechanical protection from injury Transitional Epithelia Transitional epithelium: A transitional epithelium (also known as urothelium) is made up of several layers of cells that become flattened when stretched. It lines most of your urinary tract and allows your bladder to expand. General Functions of Epithelial Tissues What are the functions of epithelial tissues? General Functions of Epithelial Tissue Protection Epithelial cells from the skin protect underlying tissue from mechanical injury, harmful chemicals, invading bacteria and from excessive loss of water Sensation Sensory stimuli penetrate specialized epithelial cells Specialized epithelial tissue containing sensory nerve endings is found in the skin, eyes, ears, nose and on the tongue Secretion In glands, epithelial tissue is specialized to secrete specific chemical substances such as enzymes, hormones and lubricating fluids Absorption Certain epithelial cells lining the small intestine absorb nutrients from the digestion of food Excretion Epithelial tissues in the kidney excrete waste products from the body and reabsorb needed materials from the urine Sweat is also excreted from the body by epithelial cells in the sweat glands Diffusion Simple epithelium promotes the diffusion of gases, liquids and nutrients summary The term "epithelium" refers to layers of cells that line hollow organs and glands It is also those cells that make up the outer surface of the body. Cells of epithelial tissue appear

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Bones and Disorders of Connective Tissue CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Bones and Disorders of Connective Tissue using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Structure and Functions of Bone Tissues Definition Of Bone Bones and Disorders of Connective Tissue Bone consists of: Bone Cells; The bone contains four types of cells namely the osteoprogenator cells, osteoblasts, osteocytes, and the osteoclasts Types of Bones Parts of the long bone Bones Formation Bones formation occurs in four main stages which are Functions of Bones Movement KEYPOINTS QUESTIONS Common Disorders of Common Disorders of Connective Tissues Common Types of Connective Tissue Diseases Acute pyrogenic arthritis Gout The disease is commonest in men over 40 years. Chronic joint disease Osteoarthritis Generalized bone disease Osteomalacia Structure and Functions of Bone Tissues PHARM. EMERENCIANA M. JAMES Definition Of Bone Bone is a hard and rigid tissue that forms the bony skeleton of the body. Bone supports the body weight, It provides attachment to muscles, Acts as lever for movements, and provides protection to organs Inside the bone there are spaces, which are filled with the bone marrow that produce red blood cells, platelets and cells of the immune system Bones and Disorders of Connective Tissue Cells of the immune system produced in bone marrow include monocytes, lymphocytes, mast cells, neutrophils, eosinophils and basophils The only difference with other connective tissues is that its ground substance is made up of inorganic salts, mostly calcium ions The bone is highly vascularized, and in living conditions the bone appears pinkish in colour Bone consists of: Cells Fibers Ground substances Bone Cells; The bone contains four types of cells namely the osteoprogenator cells, osteoblasts, osteocytes, and the osteoclasts Bone Matrix (Intercellular substance);It is made up of the collagen fibers (osteocollagenous fibers), amorphous ground substance and inorganic salts which constitute about 74% of bone mass Types of Bones Long bones e.g. femur, tibia and fibula Short bones e.g. carpals (wrist bones) Flat bones e.g. sternum, ribs and most skull bones (skull) Irregular bones e.g. vertebrae and some skull bones Sesamoid bones e.g. patella (kneecap) Parts of the long bone A long bone is one that has greater length than width. A typical long bone consists of the following parts: The diaphysis is the bone’s shaft or body—the long, cylindrical, main portion of the bone. The epiphyses (singular is epiphysis) are the proximal and distal ends of the bone. The metaphyses (singular is metaphysis) are the regions between the diaphysis and the epiphyses. Bones Formation Bones formation is commonly referred to as ossification and it occurs in two processes Intramembranous Ossification The bones that form by this process include most of skull bones such as frontal,parietal, maxilla, mandible, clavicle and parts of occipital and temporal bones. Endochondral Ossification In endochondral ossification bone is formed from the pre-existing hyaline cartilage that has the shape that closely resembles the bone to be formed. Bones and Disorders of Connective Tissue Most long and irregular bones form via endochondral ossification, such as the base of the skull, vertebral column, the pelvis and bones of the extremities (limbs). During this process the cartilage is gradually replaced by bone. Only a small amount of cartilage remains covering the articular surfaces of the joints. During endochondral ossification the bone also grows in length and width. Generally flat bones develop by intramembranous ossification while long bones develop by intra cartilaginous ossification Bones formation occurs in four main stages which are Development of the ossification canters (special membrane) Formation of bone matrix Deposition of minerals or calcification Formation of trabeculae and appearance of periosteum Functions of Bones Support The skeleton serves as the structural framework for the body by supporting soft tissues providing attachment points for the tendons of most skeletal muscles Protection The skeleton protects the most important internal organs from injury for example, cranial bones protect the brain, vertebrae (backbones) protect the spinal cord, and the ribcage protects the heart and lungs. Movement When muscles contract, they pull on bones to produce movement. Mineral homeostasis (storage and release); Bone tissue stores several minerals, especially calcium and phosphorus, which contribute to the strength of bone Blood cell production; bone marrow produces red blood cells, white blood cells, and platelets, a process called hemopoiesis KEYPOINTS Bone is a hard and rigid connective tissue that forms the bony skeleton of the body Functions of bones Bone supports the body weight, It provides attachment to muscles, Acts as lever for movements, and provides protection to organs. Inside the bone there are spaces, which are filled with the bone marrow that produce Red blood cells, platelets and cells of the immune system. Production of body cells: monocytes, lymphocytes, mast cells, neutrophils, eosinophils and basophils QUESTIONS What is bone tissue? What are the types of bones? What are the functions of bones? Common Disorders of Connective Tissues PHARM. EMERENCIANA M. JAMES Common Disorders of Connective Tissues A connective tissue diseases are diseases that affect the joints (parts of the body that connect the structures of the body together). It is presented by the inflammation of the joints (arthritis) It may be infective or non-infective. In most cases, all signs of inflammation are present (swollen joints, hot, tender and red) and there is limitation of movements Common Types of Connective Tissue Diseases Acute pyrogenic arthritis Gout Chronic joint disease Osteoarthritis Generalized bone disease Osteomalacia Osteoporosis Acute pyrogenic arthritis This is the infection of the joints by pus-producing bacteria It is caused by any pyrogenic bacteria like staphylococci. The infection may start suddenly without any obvious cause or may occur from other septic focus nearby like osteomyelitis The patients complain of pain, swelling and reduced movement of the joint Gout This is arthritis due to congenital abnormality of uric acid metabolism, leading to abnormal high uric acid in the blood. Uric acid is deposited in joints and also around the

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE A Cell CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study A Cell using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic CELL Other organisms are multicellular(consist of many cells) e.g. humans There are two types of cells: Most eukaryotic cells also contain other membrane-bound organelles such a mitochondria, and the Golgi apparatus Prokaryotic Cells Instead processes such as oxidative phosphorylation and photosynthesis take place across the prokaryotic plasma membrane. Structure of a generalized animal cell The cytosol is the liquid portion containing water and dissolved solutes. Characteristics of the Cell Growth- is the increase in the size and number of the existing cells. . Functions of the Human Cell Mitochondria Vacuole Endoplasmic Reticulum Golgi apparatus Ribosomes Lysosomes Assignment CELL Is the smallest living structural and functional unit of life It is the smallest unit of an organism that is classified as living, and is often called building block of life All cells come from pre-existing cells Most cells are microscopic and can replicate independently Some organisms are unicellular (consist of a single cell) e.g. some bacteria. Other organisms are multicellular(consist of many cells) e.g. humans Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells Cells of the body perform specific functions, and therefore their structures vary greatly There are two types of cells: 1.Eukaryotic 2.Prokaryotic Eukaryotic Cells Cells in higher animals (mammals) are eukaryotic, that is they have membrane bound nucleus, which is well protected, inside the cell Eukaryotic cells are often found in multicellular organisms Eukaryote is an organism whose cells contain complex structures inside the membranes Most eukaryotic cells also contain other membrane-bound organelles such a mitochondria, and the Golgi apparatus Eukaryotes do have "true" nuclei containing DNA Eukaryotic organisms may be unicellular, as in amoebae, or multicellular, as in humans Cell division in eukaryotes is different from that in organisms without a nucleus (prokaryotes) Prokaryotic Cells Do not contain membrane bound organelles and genetic material is scattered in the cytoplasm The simple forms of life like bacteria are made up entirely of single cell are prokaryotic, the nucleus is not membrane bound it is scattered in the protoplasm and is vulnerable Prokaryotic cells are usually independent Prokaryotes generally lack membrane-bound cell compartments: such as mitochondria and chloroplasts. Instead processes such as oxidative phosphorylation and photosynthesis take place across the prokaryotic plasma membrane. However, prokaryotes do possess some internal structures, such as cytoskeletons. Prokaryotes also differ from eukaryotes in that they contain only a single loop of stable chromosomal DNA stored in an area named the nucleoid, while eukaryote DNA is found on tightly bound and organized chromosomes Structure of a generalized animal cell The cell is divided into three main parts namely: plasma membrane, cytoplasm and nucleus The plasma membrane: Forms the cell’s outer surface separating the cell’s internal environment from the external environment. It regulates the flow of material into and out of the cell The cytoplasm: It is the fluid-filled cell interior. It has two components: cytosol and organelles. The cytosol is the liquid portion containing water and dissolved solutes. The organelles are small structures with highly specialized functions, many of which are contained within a membrane. They include nucleus, mitochondria, ribosomes, endoplasmic reticulum (ER), Golgi apparatus, cell membrane, microfilaments and microtubules. Characteristics of the Cell Metabolism-are the sum of all chemical processes that occur in the body including anabolism and catabolism. Responsiveness- ability to detect and respond to changes like temperature, pressure, sound etc. Movement- includes motion of the whole cell and tiny structures inside the cell. Growth- is the increase in the size and number of the existing cells. Differentiation- the development of a cell from unspecialized to specialized state Reproduction- the formation of new cells for tissue growth, repair and replacement or to the production of a new individual . Functions of the Human Cell The functions of animal cell are all carried out by the different cell organelles These cell organelles function as a unit and regulate the activities of the cell on the whole. Cell nucleus The nucleus is referred to as the heart of the cell The nucleus houses the genetic material of the organism which is the DNA. DNA replication and RNA synthesis occurs in the nucleus. Mitochondria The mitochondria is also referred to as the power house of the cell It is a double membrane organelle that helps in energy production for the cell. The energy is generated in the form of ATP from the glucose. This occurs in the process called cellular respiration Vacuole The vacuole is a large empty storage organelle. They store excess water or food. It is present in many numbers within the cell floating in the cytoplasm Endoplasmic Reticulum The endoplasmic reticulum is a network for transportation of certain critical substances in and out of the nucleus. There are two kinds of ER namely ; 1.Rough ER Smooth ER. Rough ER has ribosome molecules attached to its surface Smooth ER does not have ribosome molecules attached to its surface Golgi apparatus Is involved with processing and packaging of the molecules synthesized by the cell mainly the proteins ready for secretion The ER transports the proteins in their crude form to the golgi apparatus Ribosomes Is involved in protein synthesis. It consists of two sub units Protein synthesis primarily occurs in the ribosomes The ribosomes may be found freely floating in the cytoplasm or may be found attached to the ER Lysosomes Are referred to as suicide bags of the cell,they are involved in clearing the unwanted and waste materials from the cell The lysosomes contain hydrolytic enzymes that are destructive that they kill the toxic materials of the cell time to time. They engulf materials like damaged organelles, virus, bacteria and food particles Assignment Explain functions of cell organelles

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Accessory organs of digestive systems CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Accessory organs of digestive systems using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic By the end of this session, students are expected to be able to: Overview of Accessory Organs of Digestive System Accessory organs of digestive systems Structure and Functions of the Liver The Quadrate lobe Structures related to Liver The connective tissue septa divide the liver into hexagon-shaped lobules with a portal triad at each corner Functions of hepatocytes Hepatocytes have six major functions, which are: Main Functions of the Liver Breakdown of erythrocytes and defence against microbes Vascular Supply and Lymphatic Drainage Structure and functions of the Gallbladder Organisation of the Biliary System This completes the formation of the bile duct Bile Production, Circulation and Functions Bile circulation. Composition of Bile Structure and Functions of Pancreas In the lower part of the head of pancreas, the pancreatic duct joins the bile duct The main and accessory pancreatic ducts usually communicate with each other Key points evaluation Accessory Organs of Digestive System By the end of this session, students are expected to be able to: Describe the Accessory Organs of Digestive System Describe the Structure and Functions of the Liver Describe the Structure and Functions of Gallbladder Explain Organization of the Biliary System Explain Bile Production, Circulation and Functions Identify Structure of Pancreas Overview of Accessory Organs of Digestive System What are the accessory organs of the digestive system? Accessory organs of digestive systems Accessory organs of gastrointestinal tract: The organs which are not directly part of gastrointestinal tract but their products are essential for the digestive system to accomplish its primary function These organs include: The liver Gallbladder and bile duct Pancreas These are essential for the digestive system as they either produce or store secretions essential the digestion to take place Structure and Functions of the Liver Liver is the largest gland in the body, weighing between 1 and 2.3Kg In adults the liver weighs 2% of body mass Occupying the greater part the right hypochondriac, part of the epigastric and frequently extending into the left hypochondriac regions as far as the left lateral line The liver is divided into right and left lobes by fossae for the gallbladder and the inferior vena cava The right lobe of liver is the largest lobe, whereas the left lobe of liver is smaller wedge shaped The quadrate and caudate lobes are described as arising from the right lobe of liver, but functionally are distinct these are seen on the posterior side of the liver making it to have four lobes: The Quadrate lobe It is visible on the upper part of the visceral surface of the liver It is bounded on the left by the fissure for ligamentum teres and on the right by the fossa for the gallbladder Functionally it is related to the left lobe of the liver The caudate lobe It is visible on the lower part of the visceral surface of the liver It is bounded on the left by the fissure for the ligamentum venosum and on the right by the groove for the inferior vena cava Functionally, it is separate from the right and the left lobes of the liver Structures related to Liver The right anterior part of the stomach The superior part of the duodenum The lesser omentum The gallbladder The right colic flexure The right transverse colon The right kidney The right suprarenal gland Accessory organs of digestive systems The porta hepatis serves as the point of entry into the liver for the hepatic arteries and the portal vein, and the exit point for the hepatic ducts The liver is attached to the anterior abdominal wall by the falciform ligament and, except for a small area of the liver against the diaphragm (the bare area), the liver is almost completely surrounded by visceral peritoneum Additional folds of peritoneum connect the liver to the stomach (hepatogastric ligament), the duodenum (hepatoduodenal ligament), and the diaphragm (right and left triangular ligaments and anterior and posterior coronary ligaments) The connective tissue septa divide the liver into hexagon-shaped lobules with a portal triad at each corner *The triad are so named because three vessels – the hepatic portal vein, hepatic artery and hepatic duct are commonly located in them Hepatic nerves and lymphatic vessels often too small to be easily seen in light microscope are also located in these areas Liver lobules are hexagonal in outline and are formed by cubical-shaped cells; the hepatocytes arranged in pair, between them are columns of cells called sinusoids Hepatic macrophages (Kupffer cells) are also present which function in destroy and ingest worn out cells and foreign particles in the liver A central vein is in the centre of each lobule Accessory organs of digestive systems Central veins unite to form hepatic veins, which exit the liver on its posterior and superior surface and empty into the inferior vena cava Hepatic cord radiate out from the central vein of each lobule like the spokes of a wheel The hepatic cords are composed of hepatocytes, the functional cells of the liver The spaces between the hepatic cords are blood channels called hepatic sinusoids The sinusoids are lined with a very thin, irregular squamous epithelium consisting of two cell populations; endothelial cells and Hepatic phagocytic cells (kupffer cells) A cleft-like lumen, the bile canaliculus lie between the cells within each cord Functions of hepatocytes What are the function of hepatocyte Hepatocytes have six major functions, which are: o Bile production o Storage o Interconversion of nutrients o Detoxication o Phagocytosis (kuppfer cells) o Synthesis of blood components Main Functions of the Liver Nutrient and vitamin metabolism and storage o Glucose and other sugars o Amino acids (Deamination of amino acids),the end product is urea which is then excreted in the urine) o Lipids o

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Anatomy of reproductive Organs CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Anatomy of reproductive Organs using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Female Reproductive System …… Ovaries Anatomy of reproductive Organs Uterus Vagina External genitals (Vulva) Labia majora and minora Male reproductive organs Testes The testes are surrounded by three layers of tissues which are (outer-inner layer) Cells of testis Epididymis Ejaculatory ducts Seminal vesicles Their secretion contains fructose to provide an energy source for sperm and is alkaline to enhance sperm motility. Prostate gland Bulbourethral (Cowper‘s) glands Urethra Anatomy of reproductive Organs Female Reproductive System Is made up of the internal and external sex organs The female reproductive system consists of the: Internal genitalia which include: Paired ovaries Fallopian tubes Single uterus Vagina AND External genital structures (vulva) which include: Clitoris Labia majora and minora …… Bartholin‘s glands Ovaries The ovaries are a pair of oval structures on either side of the uterus in the pelvic cavity (with size approx. 3.5 cm in length, 2 cm wide, and 1 cm thick) Within an ovary are several hundred thousand primary follicles, which are present at birth and later matures to become ova Fallopian /uterine tubes or oviduct There are two fallopian tubes(oviducts) The lateral end of a fallopian tube encloses an ovary, and the medial end opens into the uterus. They are line by ciliated columnar Epithelium. Parts of Oviduct include isthmus,Ampulla and Infindubilum (contains fimbriae) !!Fertilization takes place in oviduct (ampulla) Anatomy of reproductive Organs Isthmus=narrowed part of a structure. There are two isthmuses. The one is between the body of uterus and cervix and the other is the first medial part of fallopian tube. Uterus The uterus is shaped like an upside-down pear, superior to the urinary bladder and between the two ovaries in the pelvic cavity …… Uterus…. It is divided in to fundus (upper part), body/corpus (central part),Isthmus and cervix (lower part) Layers of uterus (from innermost-outermost): Endometrium- inner lining and consists of glandular cells (simple columnar epithelium) that make secretions and undergoes cyclic shedding during menstruation It forms the maternal portion of the placenta during pregnancy Anatomy of reproductive Organs The myometrium is the smooth muscle layer during pregnancy these cells increase in size to accommodate the growing foetus and contract for labour and delivery at the end of pregnancy. Perimetrium: consists of Subserosa tissue Vagina The vagina is a muscular tube that extends from the cervix to the vaginal orifice The vaginal opening is usually partially covered by a thin membrane called the hymen which ruptures after sexual intercourse The functions of the vagina are to receive sperm from the penis during sexual intercourse, To provide the exit for menstrual blood flow, and To become the birth canal at the end of pregnancy. External genitals (Vulva) Clitoris Is a small mass of erectile tissue anterior to the urethral orifice. The only function of the clitoris is sensory. It responds to sexual stimulation. Labia majora and minora Are paired folds of skin which covers the urethra and vagina openings and prevent drying of their mucous membranes Bartholin‘s glands They secrete lubricant which keep the vagina moist during sexual intercourse. Male reproductive organs They include: Testes Epididymis Dactus deferens (vas deferens) Ejaculatory ducts ….. Seminal vesicles Prostate gland Bulbourethral (Cowper‘s) glands Urethra-penis Testes The testes are located in the scrotum, a sac of skin between the upper thighs. Internally is divided in to lobes Each lobe contains several seminiferous tubules where spermatogenesis takes place. The testes are surrounded by three layers of tissues which are (outer-inner layer) Tunica vaginalis Tunica albuginea Tunica vasculosa Cells of testis sertoli cells which produce inhibin hormone when stimulated by testosterone Leydig cells: produce Testosterone is responsible for maturation of sperm and secondary male characteristics Epididymis It is a tube about 6m long that is coiled in the posterior surface of each testis. Within it the sperm complete the maturation and their flagella become functional. … Smooth muscle of the wall of epididymis propels the sperm to dactus deferens Dactus deferens (vas deferens) Extends from the epididymis in the scrotum on its own side into the abdominal cavity through the inguinal canal … Spermatic cord is a connective tissue sheath that contains the ductus deferens, testicular blood vessels(Cremasteric artery,Testicular artery, artery to vas deferens & pampinifom venous plexus), and nerves, [well discussed in inguinal canal session] Ejaculatory ducts Each of the two ejaculatory ducts receives sperm from the ductus deferens and the secretion of the seminal vesicle on its own side. Both ejaculatory ducts empty into the single urethra Seminal vesicles The paired seminal vesicles are posterior to the urinary bladder Their secretion contains fructose to provide an energy source for sperm and is alkaline to enhance sperm motility. The duct of each seminal vesicle joins the ductus deferens on that side to form the ejaculation duct Prostate gland A muscular ,walnut-shaped gland just below the urinary bladder It surrounds the first inch of the urethra as it emerges from the bladder The glandular tissue of the prostate secretes an alkaline fluid that helps maintain sperm motility. The smooth muscle of the prostate gland contracts during ejaculation to contribute to the expulsion of semen from the urethra Bulbourethral (Cowper‘s) glands They are located below the prostate gland and empties to the urethra Their alkaline secretion coats the interior of the urethra just before ejaculation, which neutralizes any acidic urine that might be present. Urethra The urethra is the last of the ducts through which semen travels, and its longest portion is enclosed within the penis. Anatomy of reproductive Organs The penis is an external genital organ; its distal end is called the glans penis and is covered with a fold of skin called the prepuce or foreskin which is removed by surgical procedure of circumcision Within the penis are three masses of cavernous (erectile) tissue by

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Blood And Its Functions CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Blood And Its Functions using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic COMPONENTS OF THE BLOOD Blood And Its Functions The average adult has a blood volume of roughly 5 litres, composed of: Functions of Blood Function of blood Blood Plasma and Platelets Blood Platelets Production and Functions of Red Blood Cell Erythropoiesis is the process by which red blood cells (erythrocytes) are produced In the process of red blood cell maturation, a cell undergoes a series of differentiations. Regulation of Erythropoiesis Functions of Red Blood Cells As blood flows through the lungs, the carbon dioxide is released from haemoglobin and then exhaled. Production and Functions of White Blood Cells Types of White Blood Cells Agranulocytes (Mononuclear Leucocytes) Functions of White Blood Cells Eosinophil Monocyte Macrophage KEY POINTS EVALUATION Composition and Functions of Blood COMPONENTS OF THE BLOOD What are the components of blood? Blood And Its Functions Blood is the specialized( connective tissue) bodily fluid that delivers necessary substances to the body's cells such as nutrients, oxygen and transports waste products away from those same cells Blood accounts for 7% of the human body weight By volume the red blood cells constitute about 45% of whole blood, the plasma constitutes about 55% The average adult has a blood volume of roughly 5 litres, composed of: Plasma Formed elements These formed elements of the blood are Erythrocytes (red blood cells) Adult humans have roughly 2–3 × 10>13 red blood cells Leukocytes (white blood cells) and 4,000–11,000 white blood cells Thrombocytes (platelets). 150,000–400,000 platelets in each microliter Women have about 4 to 5 million erythrocytes per microliter (cubic millimeter) of blood and men about 5 to 6 million; people living at high altitudes with low oxygen tension will have more. Functions of Blood What are the functions of blood? Function of blood Supply of oxygen to tissues (bound to haemoglobin which is carried in red cells) bound to plasma proteins Removal of waste such as carbon dioxide, urea and lactic acid Immunological functions, including circulation of white cells, and detection of foreign material by antibodies Coagulation, which is one part of the body's self-repair mechanism Messenger functions, including the transport of hormones and the signalling of tissue damage Regulation of body pH (the normal pH of blood is in the range of 7.35 – 7.45) Regulation of core body temperature Blood Plasma and Platelets Blood Plasma Is the fluid portion of the blood, The plasma, is a remarkable solution containing an immense number of ions, inorganic molecules, and organic molecules that are in transit to various parts of the body or aid in the transport of other substances The normal plasma volume is about 5% of body weight, or roughly 3500 mL in a 70kg man Plasma clots on standing, remain fluid only if an anticoagulant is added If whole blood is allowed to clot and the clot is removed, the remaining fluid is called serum PLASMA Vs SERUM Blood And Its Functions Serum has essentially the same composition as plasma except that its fibrinogen an clotting factors II, V, and VIII have been removed and it has higher serotonin content because of the breakdown of platelets during clotting The plasma consist of protein; albumin, globulin, and fibrinogen fractions The capillary walls are relatively impermeable to the plasma proteins, and the proteins are therefore exerting an osmotic force of about 25 mm Hg across the capillary wall (oncotic pressure) that pulls water into the blood Blood Platelets Platelets or thrombocytes are minute fragment of cells consisting of a small amount of cytoplasm surrounded by a plasma membrane Platelets are roughly disk-shaped and an average about 3μm in diameter. They play an important role in controlling blood loss by forming platelets plugs which seal holes in small vessels The life expectancy of platelets is about 5 – 9 days Platelets arise in a unique manner by the shedding of thousands of cytoplasmic fragments from the tips of processes of megakaryocytes in the bone marrow The first detectable cell of this line is the highly basophilic megakaryoblast, followed by a promegakaryocyte stage, in which synthesis of granules begins Finally, the fully differentiated megakaryocyte, a giant cell with a large, dense, polyploid, multilobed nucleus, appears Production and Functions of Red Blood Cell Red Blood Cells Red blood cells (Erythrocytes) are the most common type of blood cell The cells are filled with haemoglobin, a biomolecule that can bind to oxygen They take up oxygen in the lungs and release it while squeezing through the body's capillaries. The blood's red colour is due to the colour of haemoglobin. In humans, red blood cells develop in the bone marrow, take the form of flexible biconcave disks, lack a cell nucleus, subcellular organelles and the ability to synthesize protein, It takes about 7 days for erythrocytes to mature and live a total of about 120 days Erythropoiesis is the process by which red blood cells (erythrocytes) are produced In human adults, this usually occurs within the bone marrow. In the early foetus, erythropoiesis takes place in the mesodermal cells of the yolk sac. By the third or fourth month, erythropoiesis moves to the spleen and liver. In humans with certain diseases, erythropoiesis also occurs outside the bone marrow, within the spleen or liver. This is termed extramedullary erythropoiesis The tibia and femur cease to be important sites of haematopoiesis by about age 25; the vertebrae, sternum, pelvis and ribs, and cranium bones continue to produce red blood cells throughout life. Erythrocytes and granulocytes belong to the myeloid lineage. The earliest identifiable erythroid stem cells are capable of rapid bursts of cell division to form numerous daughter cells. In the process of red blood cell maturation, a cell undergoes a series of differentiations. The following stages of development all occur within the bone

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Blood groups CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Blood groups using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic BLOOD GROUPS IMPORTANCE OF BLOOD GROUPING: THE HISTORY OF BLOOD TRANSFUSION ABO BLOOD GROUPS OTHER BLOOD GROUPS LANDSTEINER’S LAW FORMATION OF ANTIBODIES INHERITANCE OF ABO BLOOD GROUP GENETIC INHERITANCE OF ABO BLOOD GROUP BLOOD GROUPING THE RHESUS (Rh) BLOOD SYSTEM RHESUS CONT. CLINICAL SIGNIFICANCE OF Rh FACTOR CLINICAL SIGNIFICANT OF Rh CONT. BLOOD GROUPS Department of Physiology IMPORTANCE OF BLOOD GROUPING: Practical importance of blood grouping includes: Blood transfusion Paternity disputes Medicolegal use eg blood stain on clothes Association with susceptibility to disease: Blood group O: more susceptible to peptic ulcers Blood group A : more susceptible to carcinoma of stomach THE HISTORY OF BLOOD TRANSFUSION In 1901 Karl Landsteiner published his work He discovered the ABO blood group system by mixing blood samples from his colleagues Later, it was also noted that: Some people were given blood with no reaction While others received blood there were some reactions even death Landsteiner and Weiner discovered Rh system (1940) The best known groups are the ABO & Rhesus systems are of great importance in blood transfusion today ABO BLOOD GROUPS Depending on the presence or absence of A & B antigens, humans can be divided into A, B, AB & O groups The antibodies reacting with the: Antigen A is called antibody A (alpha) Antigen B is called antibody B (beta) Antigen O is not antigenic and has no corresponding antibodies The prevalence of ABO blood groups among the Europeans: TYPE FREQUENCY (%) O 47 A 41 B 9 AB 3 OTHER BLOOD GROUPS In addition to the ABO & Rh blood groups are: M, N, P, Lutheran, Kell, Duffy, Kid, Diego etc etc These blood groups have demonstrable antigens but the corresponding antibodies in the plasma are generally not present. LANDSTEINER’S LAW The Law states that: “If an antigen (agglutinogen) is present on the Rbc of an individual, the corresponding antibody (agglutinin) must be absent and that IF an antigen is absent on the Rbc of an individual, corresponding antibody must be present in the plasma” LANDSTEINER’S LAW Blood groups, antigens & antibodies according to Landsteiner’s law: Blood group Antigens Antibodies O NO A & B A A B B B A AB A & B NO FORMATION OF ANTIBODIES The specific blood group antibodies (Antibodies A & B) are absent at birth, but they appear and reach a maximum concentration by the age of 10 years. INHERITANCE OF ABO BLOOD GROUP ABO blood groups are inherited in accordance with Mendelian principle: by a means of 3allelic genes A, B, and O. The A & B genes are co-dominant while O gene is functionless ie has no demonstrable product GENETIC INHERITANCE OF ABO BLOOD GROUP GENETIC OFFSPRING From Parent-1 Parent-2 Genotype Phenotype A B AB AB A A AA A A O AO A B B BB B B O BO B O O OO O BLOOD GROUPING Before blood transfusion, the patient’s (recipient) and donor’s blood group are determined. Anti A Anti B Blood Group Cells 1 – – O Cells 2 + – A Cells 3 – + B Cells 4 + + A & B NB: + Reaction & – No reaction THE RHESUS (Rh) BLOOD SYSTEM The Rh System derives its name from the findings that the antibody produced in the rabbit by injection of Rbc from the Rhesus monkey would: Agglutinate 85% of human cells (Rhesus Positive) The remaining 15% could not agglutinate (Rhesus Negative) This type of antibody was also found in: Some people who had transfusion before. Mothers who had given birth to a child with Haemolytic Disease of the Newborn (HDN) People who were originally labelled as Rhesus positive (Rh + ve) have actually the D antigen on their Rbc’s membrane RHESUS CONT. Similar to D antigens are C & D antigens, but are not clinically important D antigen is much more potent ie it stimulate antibody production with greater frequency than any other Rh antigen CLINICAL SIGNIFICANCE OF Rh FACTOR Although there are no natural antibody Rh(D) These antibodies can however develop in two ways: When an Rh Negative person is given Rh positive blood. First transfusion of Rh+ve into Rh-ve there will be no reaction However subsequent transfusion of Rh+ve of blood causes haemolysis of transfused blood due to Anti Rh (D) CLINICAL SIGNIFICANT OF Rh CONT. When an Rh –ve mother gets Rh +ve fetus from a Rh +ve father. Thefirst pregnancy will have no reaction However, subsequent pregnancies with Rh+ve fetus result into Haemolytic Disease of the Newborn (HDN) THANK YOU ← PREVIOUS TOPICNEXT TOPIC →VIEW ALL MODULE NOTESVIEW SEMESTER NOTESVIEW ALL LEVEL NOTESALL DIAGNOSTIC RADIOLOGY NOTES Need These Notes as PDF? Need a clean, well-formatted PDF copy for offline study, revision or printing? Request the complete notes directly through WhatsApp. GET WELL-FORMATTED PDF NOTES

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Body Cavities And Membranes CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Body Cavities And Membranes using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Cavity is an empty space in the body of multicellular organism,containing the viscera or fluid. DORSAL BODY CAVITY VENTRAL BODY CAVITY The superior subdivision, is surrounded by the ribs and muscles of the chest. The abdominopelvic cavity, has two parts. When the body is subjected to physical trauma e.g MTA/RTA, the abdominopelvic organs are most vulnerable. MEMBRANES IN THE VENTRAL BODY CAVITY Body Cavities And Membranes When serous membranes are inflamed, their normally smooth surfaces become roughened. ABDOMINOPELVIC REGIONS AND QUADRANTS The umbilical region is the centermost region deep to and surrounding the umbilicus (navel). Medical personnel usually use a simpler scheme to localize the abdominopelvic cavity organs . OTHER BODY CAVITIES 4. Middle ear cavities. The middle ear cavities carved into the skull lie just medial to the eardrums. BODY CAVITIES AND MEMBRANES Cavity is an empty space in the body of multicellular organism,containing the viscera or fluid. Membrane is a thin sheet of tissue or layers of cells acting as a boundary,lining,or partition in an organism. DORSAL BODY CAVITY The dorsal body cavity, which protects the fragile nervous system organs, has two subdivisions. The cranial cavity, in the skull, encases the brain. The vertebral, or spinal, cavity, which runs within the bony vertebral column, encloses the delicate spinal cord. The spinal cord is essentially a continuation of the brain, and the cranial and spinal cavities are continuous with one another VENTRAL BODY CAVITY The more anterior and larger of the closed body cavities is the ventral body cavity . Like the dorsal cavity, it has two major subdivisions: The thoracic cavity. 2.The abdominopelvic cavity. The ventral body cavity houses internal organs collectively called the viscera, or visceral organs. The superior subdivision, is surrounded by the ribs and muscles of the chest. The thoracic cavity is further subdivided into lateral pleural cavities, each enveloping a lung, and the medial mediastinum. The mediastinum contains the pericardial cavity, which encloses the heart, and it also surrounds the remaining thoracic organs. The thoracic cavity is separated from the more inferior abdominopelvic cavity by the diaphragm, a dome-shaped muscle important in breathing The abdominopelvic cavity, has two parts. However, these regions are not physically separated by a muscular or membrane wall. Its superior portion, the abdominal cavity, contains the stomach, intestines, spleen, liver, and other organs. The inferior part, the pelvic cavity, lies in the bony pelvis and contains the bladder, some reproductive organs, and the rectum. The abdominal and pelvic cavities are not aligned with each other. Instead, the bowl-shaped pelvis tips away from the perpendicular. When the body is subjected to physical trauma e.g MTA/RTA, the abdominopelvic organs are most vulnerable. This is because the walls of the abdominal cavity are formed only by trunk muscles and are not reinforced by bone. The pelvic organs receive a somewhat greater degree of protection from the bony pelvis. MEMBRANES IN THE VENTRAL BODY CAVITY The walls of the ventral body cavity and the outer surfaces of the organs it contains are covered by a thin, double-layered membrane, the serosa, or serous membrane. The part of the membrane lining the cavity walls is called the parietal serosa. It folds in on itself to form the visceral serosa, covering the organs in the cavity. Body Cavities And Membranes In the body, the serous membranes are separated not by air but by a thin layer of lubricating fluid, called serous fluid, which is secreted by both membranes. Although there is a potential space between the two membranes, the barely present, slitlike cavity is filled with serous fluid. Body Cavities And Membranes The slippery serous fluid allows the organs to slide without friction across the cavity walls and one another as they carry out their routine functions. The serous membranes are named for the specific cavity and organs with which they are associated. The parietal pericardium lines the pericardial cavity and reflects back as the visceral pericardium, which covers the heart. Likewise, the parietal pleura lines the walls of the thoracic cavity, and the visceral pleura covers the lungs. The parietal peritoneum is associated with the walls of the abdominopelvic cavity, while the visceral peritoneum covers most of the organs within that cavity. When serous membranes are inflamed, their normally smooth surfaces become roughened. This leads to excruciating pain as the organs stick together and drag across one another, as anyone who has experienced pleurisy (inflammation of the pleurae) or peritonitis (inflammation of the peritonea) ABDOMINOPELVIC REGIONS AND QUADRANTS Because the abdominopelvic cavity is large and contains several organs, it helps to divide it into smaller areas for study. One division method, used primarily by anatomists, uses two transverse and two parasagittal planes. These planes, positioned like a tic-tac-toe grid on the abdomen, divide the cavity into nine regions The umbilical region is the centermost region deep to and surrounding the umbilicus (navel). The epigastric region is located superior to the umbilical region. The hypogastric (pubic) region is located inferior to the umbilical region. The right and left iliac, or inguinal, regions are located lateral to the hypogastric region. The right and left lumbar regions lie lateral to the umbilical region. The right and left hypochondriac regions flank the epigastric region laterally. Medical personnel usually use a simpler scheme to localize the abdominopelvic cavity organs . In this scheme, one transverse and one median sagittal plane pass through the umbilicus at right angles. The resulting quadrants are named according to their positions from the subject’s point of view: The right upper quadrant (RUQ), Left upper quadrant (LUQ), Right Lower quadrant (RLQ), and Left lower quadrant (LLQ). OTHER BODY CAVITIES In addition to the large closed body cavities, there are several smaller body cavities. Most of these are in the head