Diagnostic Radiology Notes

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Endocrine System CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Endocrine System using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Is a biochemical communication network through which several small glands control a broad range of vital body activities. The endocrine glands are: Posterior pituitary gland. Anterior pituitary gland Adrenocorticotropic hormone (ACTH) stimulates the secretion of cortisol and other hormones by the adrenal cortex. Thyroid gland Calcitonin Pancreas Endocrine System Adrenal glands Ovaries Testes Hormones may be The general functions of the endocrine system include: Common Endocrine disorders Radiographic features; Findings of secondary and tertiary hyperparathyroidism includes; Subperiosteal resorption Brown tumor Hyperpituitarism Generalized overgrowth of all the body tissues is the underlying abnormality in acromegaly. Thickened calvarium with pituitary enlargement Acromegaly. Lateral skull projection demonstrating a thickened frontal bone with characteristic frontal bossing Pituitary microadenoma Hypopituitarism Hypothyroidism AP of the pelvis in a child with hypothyroidism (cretinism). Vitamin related bone disease Rickets and osteomalacia liver disease Osteomalacia Radiographic appearance Rickets Causes of Vitamin D deficiency include : Radiographic Features cont…. Scurvy Disorders of the Growth hormone: Disorders of the thyroxine Diabetes Mellitus Type 2 is called non–insulin-dependent diabetes, and its onset is usually later in life (maturity onset). Disorders of the adrenal cortex Cushing’s syndrome ENDOCRINE SYSTEM Is a biochemical communication network through which several small glands control a broad range of vital body activities. The endocrine glands secrete chemical messengers called hormones, which circulate in the blood and may affect a single target organ or the entire body. The endocrine glands are: Pituitary gland Thyroid gland Parathyroid gland Adrenal gland Pancreas Ovaries Testes Pituitary gland It hangs from the hypothalamus and is enclosed by the sphenoid bone. It is divided into posterior pituitary gland and anterior pituitary gland. Posterior pituitary gland. The two hormones of the posterior pituitary gland are produced by the hypothalamus and stored in the posterior pituitary gland until needed These hormones are anti-diuretic hormone (vasopressin) and oxytocin and both are peptides. Antidiuretic hormone increases the reabsorption of water by kidney tubules, which decreases the amount of urine formed. The water is reabsorbed into the blood, so as urinary output is decreased, blood volume is increased, which helps maintain normal blood pressure Oxytocin stimulates contraction of the uterus at the end of pregnancy and stimulates release of milk from the mammary glands. Anterior pituitary gland The hormones produced are regulated by releasing hormone from the hypothalamus. The hormones produced are growth hormones (somatotropin), thyroid stimulating hormone, adrenocorticotropic hormone, prolactin, follicle stimulating hormone and luteinizing hormone. Growth hormones promote growth as increases amino acids transport and protein synthesis. Thyroid stimulating hormone stimulates the normal growth of the thyroid and the secretion of thyroxine (T4) and triiodothyronine (T3). Adrenocorticotropic hormone (ACTH) stimulates the secretion of cortisol and other hormones by the adrenal cortex. Secretion of ACTH is increased by corticotropin-releasing hormone (CRH) from the hypothalamus. Prolactin is responsible for lactation. More precisely, prolactin initiates and maintains milk production by the mammary glands. Follicle stimulating hormone stimulates the growth of ovarian follicles; that is, it initiates egg development in cycles of approximately28 days. Luteinizing hormone is responsible for ovulation, the release of a mature ovum from an ovarian follicle. Thyroid gland The thyroid gland is located on the front and sides of the trachea just below the larynx The structural units of the thyroid gland are thyroid follicles, which produce thyroxine (T4) and triiodothyronine(T3) and iodine is necessary foe production of these hormones Thyroxine and T3 Thyroxine (T4) and T3 have the same functions: regulation of energy production and protein synthesis, which contribute to growth of the body and to normal body functioning throughout life. Thyroxine and T3 increase cell respiration of all food types (carbohydrates, fats, and excess amino acids) and thereby increase energy and heat production. Calcitonin Decreases the reabsorption of calcium and phosphate from the bones to the blood, thereby lowering blood levels of these minerals. This function of calcitonin helps maintain normal blood levels of calcium and phosphate and also helps maintain a stable, strong bone matrix Parathyroid gland They produce a hormone called parathyroid hormone. Parathyroid hormone is an antagonist of calcitonin It increases the reabsorption of calcium and phosphate from bones to the blood, thereby raising their blood levels. And also increase their absorption from the intestine. Pancreas It is located in the upper left quadrant of the abdominal cavity, extending from the curve of the duodenum to the spleen. It is also an exocrine gland. The pancreatic hormones are produced by the cells called islet of Langerhans and the hormones are insulin and glucagon. Endocrine System Glucagon stimulates the liver to change glycogen to glucose (this process is called glycogen lysis, which literally means “glycogen breakdown”) and to increase the use of fats and excess amino acids for energy production. The overall effect of glucagon, therefore, is to raise the blood glucose level and to make all types of food available for energy production and is stimulated by hypoglycaemia. Insulin increases the transport of glucose from the blood into cells by increasing the permeability of cell membranes to glucose. A deficiency of insulin or in its functioning is called diabetes mellitus. Adrenal glands The two adrenal glands are located one on top of each kidney. Each adrenal gland consists of two parts: an inner adrenal medulla and an outer adrenal cortex. The cells of the adrenal medulla secrete epinephrine and norepinephrine, which collectively are called catecholamine sand are sympathomimetic. Epinephrine (Adrenalin) and norepinephrine (noradrenalin) are both secreted in stress situations and help prepare the body for “fight or flight.” Endocrine System The adrenal cortex secretes three types of steroid hormones: mineralocorticoids, glucocorticoids and sex hormones (oestrogens and androgens). Aldosterone is a mineralocorticoid and increases the reabsorption of sodium and the excretion of potassium by the kidney tubules hence maintains normal blood volume and blood pressure. Cortisol is a glucocorticoid and

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Epithelial Tissue CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Epithelial Tissue using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Objectives EPITHELIAL TISSUE It also forms all glands including endocrine and exocrine glands. Classification of Epithelial Tissues Classification based on number of layers (Stratification) Simple Squamous Epithelium Simple Cuboidal Epithelium Simple Columnar Epithelium Stratified squamous epithelium General Functions of Epithelial Tissue Secretion Assignment EPITHELIAL TISSUE Objectives By the end of this session students are expected to be able to: Define Epithelial Tissue Describe the Structure of Epithelial Tissues Classify Epithelial Tissues Explain Functions of Epithelial Tissues EPITHELIAL TISSUE 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 and 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 whereas the differences reflect the functions of the epithelium. Classification of Epithelial Tissues Classification according to the cell shape Squamous cells These are flat cells with an irregular flattened shape Cuboidal cells They have a shape similar to a cube, meaning its width is the same size as its height Columnar cells They are taller than they are wide Classification based on number of layers (Stratification) 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: 1.Simple squamous epithelium 2.Simple cuboidal epithelium 3.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 gland sand 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 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. 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. Assignment Outline types and functions of epithelial tissues If you fail to plan,you have plan to fail ← 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 Female Reproductive System CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Female Reproductive System using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Components of the Female Reproductive System The female reproductive system: Female Reproductive System Fertilization The female reproductive system consists of the: Egg cells (ova) are produced in the ovaries and travel through the fallopian tubes to the uterus. Structures and Functions of the Female Reproductive System Ovaries Luteinizing hormone stimulates Graafian follicle (matured follicle) and cause ovulation Fallopian tubes The smooth muscles along it propels the ovum towards the uterus Uterus Vagina The functions of the vagina are to receive sperm from the penis during sexual intercourse, External genitals (Vulva) Labia majora and minora Oogenesis This hormone also stimulates the follicle cells to secrete estrogen, which promotes the maturation of the ovum. The other three cells produced are called polar bodies. They have no function, and will simply deteriorate. Menstrual cycle Menstrual phase The average time is 3-6 days 2. Follicular phase Ovulation phase 3. Luteal phase Without progesterone, the endometrium cannot be maintained and begins to slough off in menstruation. Also secreted by the corpus luteum during a cycle are the hormones inhibin and relaxin. Key points Evaluation Structure and Functions of the Female Reproductive System Components of the Female Reproductive System What is female reproductive system? What is fertilization? What are the components of the female reproductive system? The female reproductive system: Made up of the internal and external sex organs that function in human reproduction. Female Reproductive System The female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a foetus to full term Fertilization Is the fusion/union of male and female gametes, during sexual reproduction, to form a zygote The female reproductive system consists of the: Paired ovaries Fallopian tubes Single uterus Vagina External genital structures Egg cells (ova) are produced in the ovaries and travel through the fallopian tubes to the uterus. The uterus is the site for the growth of the embryo-foetus Structures and Functions of the Female Reproductive System What are the structures and functions of the female reproductive system? Ovaries The ovaries are a pair of oval structures on either side of the uterus in the pelvic cavity Within an ovary are several hundred thousand primary follicles, which are present at birth. Female Reproductive System Each primary ovarian follicle contains an oocyte, a potential ovum or egg cell. Surrounding the oocyte are the follicle cells, which secrete estrogen. Luteinizing hormone stimulates Graafian follicle (matured follicle) and cause ovulation Ruptured follicle become corpus luteum and begins to secrete progesterone and oestrogen Fallopian tubes There are two fallopian tubes(oviducts) The lateral end of a fallopian tube encloses an ovary, and the medial end opens into the uterus. The smooth muscles along it propels the ovum towards the uterus The ovum is fertilized in the fallopian tube and swept to the uterus Uterus The uterus is shaped like an upside-down pear, superior to the urinary bladder and between the two ovaries in the pelvic cavity Female Reproductive System During pregnancy the uterus increases greatly in size, contains the placenta to nourish the embryo-foetus, and expels the baby at the end of gestation. It is divided in to fundus (upper part), body (central part) and cervix (lower part) Female Reproductive System 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. The lining of the uterus is the endometrium, forms the maternal portion of the placenta during pregnancy 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) The external female genitalia includes: 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. Oogenesis How an egg cell is produced? Oogenesis It is the process of meiosis for egg cell formation; it begins in the ovaries and is also regulated by hormones. Follicle stimulating hormone initiates the growth of ovarian follicles, each of which contains an oogonium, a stem cell for egg cell production This hormone also stimulates the follicle cells to secrete estrogen, which promotes the maturation of the ovum. For each primary oocyte that undergoes meiosis, only one functional egg cell is produced. The other three cells produced are called polar bodies. They have no function, and will simply deteriorate. A mature ovarian follicle actually contains the secondary oocyte; the second meiotic division will take place if and when the egg is fertilized. Female Reproductive System The production of ova begins at puberty (10 to 14years of age) and continues until menopause (45 to 55years of age), when the ovaries atrophy and no longer respond to pituitary hormones. Female Reproductive System Note; Oogenesis is the unequal cell division of which produces one to three polar bodies that later degrade, as well as a single haploid ovum, which is produced only if there is penetration of the secondary oocyte by a sperm cell. Menstrual cycle The menstrual cycle includes the activity of the hormones of the ovaries and anterior pituitary gland and the resultant changes in the ovaries (ovarian cycle) and uterus (uterine cycle).

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Inflammation And Wound Healing CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Inflammation And Wound Healing using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic INFLAMMATION AND WOUND HEALING Definition Cardinal signs of inflammation How to name the inflammation Acute inflammation Persistent arteriolar dilatation to increase blood flow in the affected site; leads to heat and redness( erythema) 2. Cellular phase After adhesion, leukocytes move to the extracellular space through the gap in the endothelial cells (emigration) The steps of the inflammatory response SPECIAL TYPES OF INFLAMATION CHRONIC INFLAMMATION Two major characteristic features of chronic inflammation causes ii. Persistent indigestible material. iv. Hypersensitivity reactions; inappropriate immune response to generally harmless antigen. MACROPHAGE IN CHRONIC INFL. Diseases involving chronic inflammation. Management WOUND HEALING Angiogenesis : formation of new blood vessels to supply oxygen and nutrients to the healing tissue Pathological issues in wound healing Key players Bone healing involves several stages Systemic factors INFLAMMATION AND WOUND HEALING Ms.Happy.BscMIR.2025. Definition Inflammation is dynamic process by which living vascularized tissues reacts to injury. Causes Physical e.g. trauma, temperature, radiation Infection e.g. bacteria, viruses, parasites Chemical e.g. acids, organic compounds Immunological e.g. antigen-antibody Under normal circumstances inflammation is a protective response, a goal of which is to eliminate the initial cause of injury, however if triggered or directed inappropriately, inflammatory response itself can be harmful and cause tissue and organ destruction. Cardinal signs of inflammation Rubor(redness): dilatation of small blood vessels in damaged area. Calor(heat): increased blood flow(hyperemia) Tumor(swelling): accumulation of fluid in interstitial space(edema) Dolor(pain):distortion of tissue from edema especially pus. Loss of function: movement hindered How to name the inflammation Using suffix – itis after the name of the organs/site involved Eg Pancreatitis Hepatitis Encephalitis Meningitis Peritonitis Myocarditis This is not applicable to other organs/sites,eg:- Pleurisy- inflammation of the pleura Pneumonia- inflammation of the lungs Acute inflammation Is a rapid response to injurious stimuli, short acting, minutes to days. Pathogenesis of events Vascular phase Tissue injury Release of chemical for local response (histamine, prostaglandin, bradykinin, leukotriene etc) The immediate response is vasoconstriction, it may last about 3-5 sec, even 5 min depends on severity. Persistent arteriolar dilatation to increase blood flow in the affected site; leads to heat and redness( erythema) When the volume of blood increases, it increases intravascular hydrostatic pressure, so fluid from capillaries migrate to the tissue (exudate) 2. Cellular phase It is marked by two major events Leukocyte (WBC) movement Plasma or fluid gets discharged from the blood due to increased permeability(migration) The leukocyte in the surface contain integrin protein and endothelial cell of blood capillary consists of selectins( P&E) proteins on their surface. During the leukocyte rolling on to the endothelial cell, integrin and selectin get activated. They produce adhesion on the capillary of endothelial cell. After adhesion, leukocytes move to the extracellular space through the gap in the endothelial cells (emigration) At the site of injury several mediators get released which attract the leukocytes.( chemotaxis process) Phagocytosis Engulfment of solid particle or an agent ( cell eating) After the engulfment phagocyte release the lysosomes or degrading enzymes. This process fails to kill bacteria like m.tuberculosis The steps of the inflammatory response can be remembered as the five Rs: (1) Recognition of the injurious agent (2) Recruitment of leukocytes, (3) Removal of the agent, (4) Regulation (control) of the response, (5) Resolution (repair). SPECIAL TYPES OF INFLAMATION Catarrhal inflammation- exudative inflammation occurring exclusively on the mucous membranes of respiratory and gastrointestinal tracts and producing watery exudate of serum and mucus. Hemorrhagic inflammation:-when damage is severe there is rupture of blood vessel where hemorrhage is most striking feature, eg hemorrhagic pneumonia in fatal cases of influenza Suppurative inflammation; production of pus is the main characteristics eg abscess, peritonitis following rupture of appendix Peritonitis- purulent inflammation CHRONIC INFLAMMATION Chronic inflammation is a long term inflammatory response that can last for months or even years. Its different from acute inflammation, which is the body’s normal response to an injury or infection and resolves over time. Chronic inflammation occurs when the body continues sending out inflammatory cells and substances, even though there is no infection or injury; persistent immune response. Two major characteristic features of chronic inflammation Ongoing tissue destruction Attempt to repaire by fibrosis( with or without cell regeneration) May develop soon after an acute reaction May be insidious in onset causes Persistent infection Some organisms may be difficult to be eradicated. M. tuberculosis- tuberculosis M. leprae-leprosy T. pallidum- syphilis Fungi parasites ii. Persistent indigestible material. Endogenous- necrotic bone, necrotic adipose tissue, calcium and uric acid deposits. Exogenous- silica, asbestos fibers, suture materials. iii. Immune mediated reactions Autoimmune reactions (Rheumatoid arthritis, Systemic lupus erythromatosus(SLE), Hashimoto’s thyroiditis, Chronic autoimmune gastritis) Organ transplant rejections Unregulated immune responses ( inflammatory bowel disease e.g. ulcerative colitis) iv. Hypersensitivity reactions; inappropriate immune response to generally harmless antigen. bronchial asthma hypersensitivity pneumonitis Following acute inflammation; persistent abscess. Predominant cell type in — acute inflammation; neutrophil –chronic inflammation; macrophage Macrophages are a type of wbc of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances. MACROPHAGE IN CHRONIC INFL. Continuous recruitment from blood -blood is most important source of macrophage -Mediated by: TGF &PDGF Proliferation of macrophage at the site of inflammation. Immobilization of macrophage at the site of inflammation. mediated by migration inhibition factor (MIF) secreted by activated T. lymphocytes. Diseases involving chronic inflammation. Autoimmune diseases (e.g. lupus, rheumatoid arthritis) Cardiovascular diseases (e.g. heart disease, high blood pressure) Several cancers Gastrointestinal diseases (e.g., Crohn’s disease, inflammatory bowel disease) Lung diseases (e.g., asthma, chronic obstructive pulmonary disease) Management Eating an anti-inflammatory diet rich in fruits, vegetables and health fats. Regular exercise Managing stress Avoid smoking and excessive alc consumption. Taking medications as described by a healthcare professional. WOUND HEALING Wound healing is a complex, dynamic process that involves a series of overlapping phases to restore

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Introduction to Gastrointestinal system CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Introduction to Gastrointestinal system using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Definition and Overview of Gastrointestinal System Introduction to Gastrointestinal system Organs of the digestive tract include: The gastrointestinal tract is made of four layers of tissues: Muscular is thick layer of smooth muscle tissue which consists of inner circular layer and outer longitudinal layer Functions of the Gastrointestinal System Overall, the digestive system performs six basic processes: Structure of the Oral Cavity Structure of the Oral Cavity (The Buccal Cavity) Their ducts open opposite the last molar teeth Teeth Permanent Teeth A typical tooth has the following parts: Structure and Functions of the Tongue The dorsal mucosa is covered by numerous papillae; tiny projections, some of which bear taste buds There are four basic taste sensations Some respond to all four classic categories, others to fewer or only one Salivary Glands and its Constituents The major salivary glands are the paired parotid, submandibular and sublingual glands Mechanism of Swallowing Oral stage (mouth to oropharynx), voluntarily controlled Movement; contractions and gravity moves bolus through oesophagus and into stomach Key points evaluation assignment Introduction to Gastrointestinal System (Digestive system) Definition and Overview of Gastrointestinal System What is digestive system? What are the organs of digestive system? Introduction to Gastrointestinal system Digestive system consists of the digestive tract(alimentary canal) which is a tube extending from the mouth, pass through the thorax, abdomen and pelvis and ends at the anus and its associated accessory organs Organs of the digestive tract include: The mouth or oral cavity, which has salivary glands and tonsils as accessory organs The pharynx, or throat , with tubular mucous glands The oesophagus, with tubular mucous glands The stomach, which contains many tube like glands The small intestine, consisting of the duodenum, jejunum and ileum, with the liver, Gallbladder and pancreas as major accessory organs The large intestine, including the cecum, colon, rectum and anal canal, with mucus glands The anus Introduction to Gastrointestinal system The digestive system also consists of accessory organs which include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas Teeth aid in the physical breakdown of food, and the tongue assists in chewing and swallowing. The other accessory digestive organs produce or store secretions that flow into the GI tract through ducts to aid in the chemical breakdown of food The gastrointestinal tract is made of four layers of tissues: Mucosa is the innermost layer made up of three layers The inner epithelium Lamina propria Muscularis mucosae Submucosa this layer is composed of connective tissue, it contains numerous small glands, blood vessels, and parasympathetic nerves that form the submucosal plexus (Meissner plexus) Muscular is thick layer of smooth muscle tissue which consists of inner circular layer and outer longitudinal layer Between the two layers of muscles there is a nervous plexus called myenteric plexus (Auerbach plexus) Serosa is the outermost layer of made up of loose connective tissue (visceral peritoneum) Layers of the GI tract have various modifications to enable it to perform various functions. Functions of the Gastrointestinal System What are the functions of the digestive tract? Overall, the digestive system performs six basic processes: Ingestion: This process involves taking foods and liquids into the mouth (eating) Secretion: Each day, cells within the walls of the GI tract and accessory digestive organs secrete a total of about 7 litres of water, acid, buffers, and enzymes into the lumen (interior space) of the tract Mixing and propulsion: Alternating contractions and relaxations of smooth muscle in the walls of the GI tract mix food and secretions and propel them toward the anus This capability of the GI tract to mix and move material along its length is called motility Digestion: Mechanical and chemical processes break down ingested food into small molecules Introduction to Gastrointestinal system In mechanical digestion the teeth cut and grind food before it is swallowed, and then smooth muscles of the stomach and small intestine churn the food As a result, food molecules become dissolved and thoroughly mixed with digestive enzymes In chemical digestion the large carbohydrate, lipid, protein, and nucleic acid molecules in food are split into smaller molecules by hydrolysis Digestive enzymes produced by the salivary glands, tongue (lingual lipase), stomach, pancreas, and small intestine catalyse these catabolic reactions. A few substances in food(vitamins, ions, cholesterol, and water) can be absorbed without chemical digestion Absorption. The entrance of ingested and secreted fluids, ions, and the products of digestion into the epithelial cells lining the lumen of the GI tract is called absorption. Defecation. Wastes, indigestible substances, bacteria, cells sloughed from the lining of the GI tract, and digested materials that were not absorbed in their journey through the digestive tract leave the body through the anus in a process called defecation and the materials in form of feaces Structure of the Oral Cavity The oral cavity or mouth is that part of the digestive tract bounded by the lips anteriorly, the fauces throat; opening into the pharynx posteriorly, cheeks laterally, the palate superiorly, and a muscular floor inferiorly The oral cavity is lined throughout with mucus membrane consisting of stratified squamous epithelium containing small mucus secreting glands. The oral cavity is divided into two regions: o The Vestibule; part of the mouth between Gums and Cheeks o The oral cavity proper; which lies medial to the alveolar processes (gums) Muscles of oral cavity Orbicularis oris (kiss muscle) Structure of the Oral Cavity (The Buccal Cavity) Lips: Are muscular structure formed mostly by the orbicularis oris muscles They are covered externally by skin and internally The junction between skin and mucous membrane is highly sensitive When lips are closed, line of contact is oral fissure Cheeks The cheeks are formed in large part by buccinators muscles covered They form the lateral boundaries of the oral cavity,

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Lymphatic system and its diseases CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Lymphatic system and its diseases 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: Definition and Organization of Lymphatic System Composition of Lymphatic System Lymphatic system and its diseases Tonsils They are: Thymus Spleen The white pulp is lymphatic tissue consisting mainly of lymphocytes around arteries. Bone marrow Functions of Lymph System Plasma filters into the interstitial spaces from blood flowing through the capillaries. If this would continue over even a brief period of time, the increased interstitial fluid would cause massive oedema. Absorption and transport of dietary fat, Immunity Common Disorder of the Lymphatic System Lymphadenopathy Lymphedema This most commonly occurs in women who have had surgery to remove a breast cancer. Infectious causes of lymphangitis Lymphoma Key Points Evaluation Assignment Structure, Functions and Common Disorders of Lymphatic System By the end of this session students are expected to be able to: Define Lymphatic System Explain the Organization of Lymphatic System the Structures Lymphatic System Describe Functions of Lymph System List the Common Disorders of the Lymphatic System What is lymphatic system? Definition and Organization of Lymphatic System Lymphatic system: A network of tissue, organs, and vessels that help to maintain the body‘s fluid balance, cleanse the body fluid of foreign matter and provide immune cells (lymphocytes) for defence Composition of Lymphatic System Lymph, the fluid corrected by the system from the interstitial spaces of the tissue and returns to the bloodstream. Lymphatic plexuses, networks of small lymphatic vessels, lymphatic capillaries, that originate in the extracellular spaces of most tissues. Lymphatic system and its diseases Lymphatic vessels (lymphatics), a nearly body wide network of thin-walled vessels with valves, originating from lymphatic plexuses along which lymph nodes are located. Lymph nodes, small masses of lymphatic tissue through which lymph is filtered on its way to the venous system. Lymphocytes, circulating cells of the immune system that react against foreign materials/microbes. Lymphatic system and its diseases Lymphoid tissue, sites that produce lymphocytes, such as that found in the walls of the digestive tract; in the spleen, thymus, and lymph nodes; and in myeloid tissue in red bone marrow. Lymphatic system and its diseases The lymphoid tissue is primarily involved in immune responses, and consists of lymphocytes and other white blood cells enmeshed in connective tissue through which the lymph passes. Lymphatic system and its diseases The lymphatic system differs from the circulatory system in the way that, the lymphatic do not form a closed ring or circuit. Instead, it begins blindly in the intercellular spaces of the soft tissues of the body. The Specialized organs of the lymphatic system are tonsils, thymus, bone marrow and spleen. Tonsils Masses of lymphoid tissue located in a protective ring under mucous membranes in the mouth and back of the throat. Help protect against bacteria that may invade tissues in the area around the openings between the oral and nasal cavities. They are: Palatine tonsils; located on each side of the throat. Pharyngeal tonsils; are near the posterior openings of the nasal cavity. Lingual tonsils; located near the base of the tongue Lymphatic system and its diseases The tonsils serve as the first line of defence from the exterior and as such are subject to chronic infection (tonsillitis). Thymus The thymus is located inferior to the thyroid gland. In the foetus and infant, the thymus is large and extends under the sternum Lymphatic system and its diseases The thymus hormones are necessary for immunological competence by enabling the T-cells to participate in the recognition of foreign antigens and provide immunity. This capability of T cells is established early in life and then is perpetuated by the lymphocytes themselves. Lymphatic system and its diseases The new-born‘s immune system is not yet fully mature, and infants are more susceptible to certain infections than are older children and adults. Usually by the age of 2 years, the immune system matures and becomes fully functional Spleen A soft, elongated wedge shaped purple organ Spleen is located in the left hypochondrium directly below the diaphragm, above the left kidney and descending colon, and behind the fundus of the stomach … The white pulp is lymphatic tissue consisting mainly of lymphocytes around arteries. The red pulp consists of venous sinuses filled with blood and cords of lymphatic cells, such as lymphocytes and macrophages. Arteries leading into each compartment are surrounded by dense masses (nodules) of developing lymphocytes Lymphatic system and its diseases Near the outer regions of each compartment is tissue called red pulp made up of fine reticular fibres submerged in blood that comes from nearby arteries. Lymphatic system and its diseases After passing through the reticular meshwork, blood collects in venous sinuses and then returns to the heart through Subclavian veins. Bone marrow Bone marrow is responsible for the production of blood cells: red blood cells, white blood cells, and platelets. Bone marrow stem cells play an important role in immunity as they generate lymphocytes Functions of Lymph System Maintenance of fluid balance in the body It returns excess fluid and proteins from the tissues that cannot be returned through the blood vessels. Lymphatic system and its diseases The fluid is found in tissue spaces and cavities, in the tiny spaces surrounding cells, known as the interstitial spaces. These are reached by the smallest blood and lymph capillaries Proteins that accumulate in the interstitial spaces can return to the blood only via lymphatic vessels. Plasma filters into the interstitial spaces from blood flowing through the capillaries. Much of this interstitial fluid is absorbed by tissue cells or reabsorbed by the blood before it flows out of the tissue. A small amount of interstitial fluid is left behind. Lymphatic system and its diseases Loss of the lymphatic system would be fatal within

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Male Reproductive System CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Male Reproductive System 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: Composition of Male Reproductive System Male Reproductive System The reproductive glands produce secretions that become part of semen, the fluid that is ejaculated from the urethra. Structures and Functions of Male Reproductive System Structures of the male reproductive system Seminal vesicles Functions of the male reproductive system Epididymis Smooth muscle of the wall of epididymis propels the sperm to dactus deferens Inguinal canal is a natural weak spot where most of hernia is formed in men. Ejaculatory ducts Their secretion contains fructose to provide an energy source for sperm and is alkaline to enhance sperm motility. Prostate gland The glandular tissue of the prostate secretes an alkaline fluid that helps maintain sperm motility. Bulbourethral (Cowper‘s) glands Urethra-penis Spermatogenesis For each primary spermatocyte that undergoes meiosis, four functional sperm cells are produced. The sperm cell and semen Within the middle piece are mitochondria that produce ATP. It is the beating of the flagellum that requires energy from ATP. Semen consists of sperm and the secretions of the seminal vesicles, prostate gland, and bulbourethral glands During ejaculation, approximately 2 to 4 mL of semen is expelled. Key Points Evaluation Structure and Functions of the Male Reproductive System By the end of this session students are expected to be able to: Define Male Reproductive System Explain the Composition of Male Reproductive System Describe Structure and Functions of the Male Reproductive System Explain the Process of Spermatogenesis Composition of Male Reproductive System What is the composition of male reproductive system? Male Reproductive System Male reproductive system: Is the genital system, reproductive system organs and tissues involved in the production and maturation of gametes and in their union and subsequent development as offspring. The male reproductive system consists of the testes and a series of ducts and glands. Male Reproductive System Sperm are produced in the testes by a process of spermatogenesis and are transported through the reproductive ducts: epididymis, ductus deferens, ejaculatory duct, and urethra The reproductive glands produce secretions that become part of semen, the fluid that is ejaculated from the urethra. These glands are the seminal vesicles, prostate gland, and bulbourethral glands. Structures and Functions of Male Reproductive System What are the structures and functions of the male reproductive system? Structures of the male reproductive system Testes Epididymis Dactus deferens (vas deferens) Ejaculatory ducts Seminal vesicles Prostate gland Bulbourethral (Cowper‘s) glands Urethra-penis Functions of the male reproductive system 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. Among the produced spermatogonia are Sertoli cells which produce inhibin hormone when stimulated by testosterone Male Reproductive System Between the loops of the seminiferous tubules are interstitial cells called Leydig cells which produce testosterone when stimulated by luteinizing hormone from anterior pituitary gland 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 Male Reproductive System Spermatic cord is a connective tissue sheath that contains the ductus deferens, testicular blood vessels (arteries+veins), and nerves Inguinal canal is a natural weak spot where most of hernia is formed in men. The smooth muscle layer of the ductus deferens contracts in waves of peristalsis as part of ejaculation 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 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-penis The urethra is the last of the ducts through which semen travels, and its longest portion is enclosed within the penis. Male Reproductive System 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 Male Reproductive System Within the penis are three masses of cavernous (erectile) tissue by which the flow of blood to these masses through arteries cause penile erection. Spermatogenesis It is the process of meiosis as it takes place in the testes, the site of sperm production. Within each testis are seminiferous tubules that contain spermatogonia, which are stem cells that generate sperm. Male Reproductive System A spermatogonium divides by mitosis to form two cells, one of which will remain in place as a stem cell, while the other differentiates (specializes) to become a primary spermatocyte that will undergo meiosis. Gamete formation is regulated by

DIAGNOSTIC RADIOGRAPHY · NTA LEVEL 4 · SEMESTER ONE Muscle Tissue-Structure And Functions CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Muscle Tissue-Structure And Functions using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Muscle Tissue Skeletal Muscles- 6 Functions of Skeletal Muscles Muscles serve specific functions in moving and positioning the body. How is muscle tissue organized at the tissue level? Organization of Connective Tissues 3. Endomysium Muscle Attachments Nerves What are the characteristics of skeletal muscle fibers? Skeletal Muscle Fibers Organization of Skeletal Muscle Fibers The Sarcolemma Transverse Tubules (T tubules) Muscle Striations Figure 10–6 (1 of 5) Muscle Contraction Skeletal Muscle Contraction The Process of Contraction Structure of Cardiac Tissue 7 Characteristics of Cardiocytes 4 Functions of Cardiac Tissue Role of Smooth Muscle in Body Systems Structure of Smooth Muscle 8 Characteristics of Smooth Muscle Cells Functional Characteristics of Smooth Muscle Muscle Tissue Muscle Tissue One of 4 primary tissue types, divided into: skeletal muscle cardiac muscle smooth muscle Without these muscles, nothing in the body would move and no body movement would occur Skeletal Muscles- Organs of skeletal muscle tissue are attached to the skeletal system and allow us to move Muscular System- Includes only skeletal muscles Skeletal Muscle Structures Muscle tissue (muscle cells or fibers) Connective tissues Nerves Blood vessels 6 Functions of Skeletal Muscles Produce skeletal movement Maintain body position and posture Support soft tissues Guard body openings (entrance/exit) Maintain body temperature Store Nutrient reserves Muscles serve specific functions in moving and positioning the body. The same muscle may act as a prime mover, antagonist, synergist, or fixator under specific conditions. The functions include. A prime mover or agonist is the main muscle responsible for producing a specific movement of the body (e.g. concentric contraction). Fixators steady the proximal parts of a limb while movements are occurring in distal parts. A synergist complements the action of prime mover for example, by preventing movement of the intervening joint when a prime mover passes over more than one joint. An antagonist is a muscle that opposes the action of a prime mover. As a prime mover contracts, the antagonist progressively relax, producing a smooth movement How is muscle tissue organized at the tissue level? Organization of Connective Tissues Figure 10–1 Organization of Connective Tissues Muscles have 3 layers of connective tissues: Epimysium-Exterior collagen layer Connected to deep fascia Separates muscle from surrounding tissue perimysium- Surrounds muscle fiber bundles (fascicles) Contains blood vessel and nerve supply to fascicles endomysium 3. Endomysium Surrounds individual muscle cells (muscle fibers) Contains capillaries and nerve fibers contacting muscle cells Contains satellite cells (myogenic stem cells) that repair damage Muscle Attachments Endomysium, perimysium, and epimysium come together: at ends of muscles to form connective tissue attachment to bone matrix i.e., tendon (bundle) or aponeurosis (sheet) Nerves Skeletal muscles are voluntary muscles, controlled by nerves of the central nervous system Blood Vessels Muscles have extensive vascular systems that: supply large amounts of oxygen supply nutrients carry away wastes What are the characteristics of skeletal muscle fibers? Skeletal muscle cells are called fibers Figure 10–2 Skeletal Muscle Fibers Are very long Develop through fusion of mesodermal cells (myoblasts- embryonic cells)) Become very large Contain hundreds of nuclei –multinucleate Unfused cells are satellite cells- assist in repair after injury Germ layers Structures originating from germ layers Organization of Skeletal Muscle Fibers Figure 10–3 The Sarcolemma The cell membrane of a muscle cell Surrounds the sarcoplasm (cytoplasm of muscle fiber) A change in transmembrane potential begins contractions All regions of the cell must contract simultaneously Transverse Tubules (T tubules) Transmit action potential – impulses through cell Allow entire muscle fiber to contract simultaneously Have same properties as sarcolemma Filled with extracellular fluid Muscle Striations A striped or striated pattern within myofibrils: alternating dark, thick filaments (A bands) and light, thin filaments (I bands) Figure 10–6 (1 of 5) Level 1: Skeletal Muscle Level 2: Muscle Fascicle Muscle Contraction Is caused by interactions of thick and thin filaments Structures of protein molecules (actin and myosin) detemine interactions Skeletal Muscle Contraction Figure 10–9 (Navigator) The Process of Contraction Neural stimulation of sarcolemma: causes excitation–contraction coupling Cisternae of Sarcoplasmic reticulum(SR) release Ca2+: which triggers interaction of thick and thin filaments consuming ATP and producing tension What are the structural and functional differences between skeletal muscle fibers and cardiac muscle cells? Structure of Cardiac Tissue Cardiac muscle is striated-involuntary muscle, found only in the heart Figure 10–22 7 Characteristics of Cardiocytes Unlike skeletal muscle, cardiac muscle cells (cardiocytes): are small have a single nucleus have short, wide T tubules 7 Characteristics of Cardiocytes have no triads have SR with no terminal cisternae are aerobic (high in myoglobin, mitochondria) have intercalated discs 4 Functions of Cardiac Tissue 1. Automaticity: – contraction without neural stimulation controlled Variable contraction tension: – controlled Extended contraction time Prevention of wave summation and tetanic contractions Role of Smooth Muscle in Body Systems Forms around other tissues In blood vessels: regulates blood pressure and flow In reproductive and glandular systems: produces movements In digestive and urinary systems: forms sphincters produces contractions In integumentary system: arrector pili muscles cause goose bumps Structure of Smooth Muscle Nonstriated tissue Figure 10–23 8 Characteristics of Smooth Muscle Cells Long, slender, and spindle shaped Have a single, central nucleus Have no T tubules, myofibrils, or sarcomeres Have no tendons or aponeuroses 8 Characteristics of Smooth Muscle Cells Have scattered myosin fibers Myosin fibers have more heads per thick filament Have thin filaments attached to dense bodies Dense bodies transmit contractions from cell to cell Functional Characteristics of Smooth Muscle Excitation–contraction coupling Length–tension relationships Control of contractions Smooth muscle tone ← 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 Muscles of the thorax CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Muscles of the thorax using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic Learning objectives Muscles of the thoracic wall Other accessory muscles of expiration/Inspiration The intercostal nerves Innervation to diaphragm Blood supply and drainage The muscles of the chest wall, neuro-vascular bundle and lymphatic drainage of the thorax Learning objectives At the end of this session, a student should be able to:- Identify the muscles making the thoracic wall Identify the main and accessory muscles of respiration Identify the neurovascular bundles of the thorax Describe the lymphatic drainage of the thorax Muscles of the thoracic wall External intercostal muscles (accessory m. of Inspiration) Internal intercostal m. (expiration) Diaphragm m. (Major m. of Inspiration) Subcostalis m. ( accessory m of expiration-forced) Transversus thoracis m. (accessory expiration) Other accessory muscles of expiration/Inspiration Serratus anterior m. (inspiration) Rectus abdominis m. (expiration) Sternocleidomastoid m. (inspiration) Scalenius m.(inspiration) Transversus abdominis (expiration) Internal oblique m.(expiration) External oblique (expiration) The diaphragm Innervation of diaphragm The neuro-vascular bundle The intercostal nerves The intercostal nerves arise from the anterior rami of the thoracic spinal nerves from T1 to T11 and are situated between adjacent ribs. Located in the costal groove Supply the intercostal muscles. Occur in the order VAN Innervation to diaphragm The phrenic nerve originates from the anterior rami of the C3,C4 and C5 nerve roots and consists of motor, sensory, and sympathetic nerve fibers. It provides complete motor innervation to the diaphragm and sensation to the central tendon aspect of the diaphragm. Blood supply and drainage The T. wall muscles receives blood from internal thoracic artery (a branch of subclavian artery). Venous drainage is through Azygous and hemiazygous veins into right and left subclavian veins Lymphatic drainage 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 Musculoskeletal CRT04101 · Anatomy, Physiology and Pathology START READING NOTES Study Musculoskeletal using the sections below. Use the topic navigation to continue through Anatomy, Physiology and Pathology. Contents of This Topic BONES AND CARTILAGES Musculoskeletal HYALINE CARTILAGES Skeletal hyaline cartilages include: ELASTIC CARTILAGES FIBROCARTILAGES CLASSIFICATION OF BONES Bones come in many sizes and shapes. 2. Short bones are roughly cube shaped. 3. Flat bones are thin, flattened, and usually a bit curved. FUNCTIONS OF BONES 2. PROTECTION. The fused bones of the skull protect the brain. 4. MINERAL AND GROWTH FACTOR STORAGE. Bone is a reservoir for minerals, most importantly calcium and phosphate. BONE STRUCTURE BONE MARKINGS These bone markings are named in different ways. BONE TEXTURES: COMPACT AND SPONGY BONE DIAPHYSIS EPIPHYSES MEMBRANES Internal bone surfaces are covered with a delicate connective tissue membrane called the endosteum . STRUCTURE OF SHORT, IRREGULAR, AND FLAT BONES LOCATION OF HEMATOPOIETIC TISSUE IN BONES BONE DEVELOPMENT FORMATION OF THE BONY SKELETON BONE HOMEOSTASIS: REMODELING AND REPAIR Spongy bone is replaced every three to four years; compact bone, every ten years. BONE REMODELING Bone deposit occurs wherever bone is injured or added bone strength is required. BONE REPAIR FRACTURES CLASSIFICATION 3. Orientation of the break relative to the long axis of the bone. 4. Whether the bone ends penetrate the skin. A fracture is treated by reduction, the realignment of the broken bone ends. Repair in a simple fracture involves four major stages Fibrocartilaginous callus formation. Bony callus formation. SKELETAL SYSTEM BONES AND CARTILAGES A skeletal cartilage is made of some variety of cartilage tissue, which consists primarily of water. The high water content of cartilage accounts for its resilience, that is, its ability to spring back to its original shape after being compressed. Musculoskeletal The cartilage, which contains no nerves or blood vessels, is surrounded by a layer of dense irregular connective tissue, the perichondrium. The perichondrium acts like a girdle to resist outward expansion when the cartilage is compressed. HYALINE CARTILAGES Which look like frosted glass when freshly exposed, provide support with flexibility and resilience. They are the most abundant skeletal cartilages. When viewed under the microscope, their chondrocytes appear spherical. The only fiber type in their matrix is fine collagen. Skeletal hyaline cartilages include: Articular cartilages, which cover the ends of most bones at movable joints. Costal cartilages, which connect the ribs to the sternum (breastbone) Respiratory cartilages, which form the skeleton of the larynx (voicebox), and reinforce other respiratory passageways. Nasal cartilages, which support the external nose. ELASTIC CARTILAGES Look very much like hyaline cartilages, but they contain more stretchy elastic fibers and so are better able to stand up to repeated bending. They are found in only two skeletal locations the external ear and the epiglottis (the flap that bends to cover the opening of the larynx each time we swallow). FIBROCARTILAGES Are highly compressible and have great tensile strength. The perfect intermediate between hyaline and elastic cartilages, fibrocartilages consist of roughly parallel rows of chondrocytes alternating with thick collagen fibers. Fibrocartilages occur in sites that are subjected to both heavy pressure and stretch, such as the padlike cartilages (menisci) of the knee and the discs between vertebrae CLASSIFICATION OF BONES The 206 named bones of the human skeleton are divided into two groups: axial and appendicular. The axial skeleton forms the long axis of the body and includes the bones of the skull, vertebral column, and rib cage. Generally speaking these bones are most involved in protecting, supporting, or carrying other body parts. Musculoskeletal The appendicular skeleton consists of the bones of the upper and lower limbs and the girdles (shoulder bones and hip bones) that attach the limbs to the axial skeleton. Bones of the limbs help to get from place to place (locomotion) and to manipulate our environment. Bones come in many sizes and shapes. For example, the pisiform bone of the wrist is the size and shape of a pea, whereas the femur (thigh bone) is nearly 2 feet long in some people and has a large ball-shaped head. The unique shape of each bone fulfills a particular need. Musculoskeletal For the most part, bones are classified by their shape as long, short, flat, and irregular . 1. Long bones, as their name suggests, are considerably longer than they are wide. A long bone has a shaft plus two ends. All limb bones except the patella (kneecap) and the wrist and ankle bones are long bones. Notice that these bones are named for their elongated shape, not their overall size. 2. Short bones are roughly cube shaped. The bones of the wrist and ankle are examples. Sesamoid bones are a special type of short bone that form in a tendon (for example, the patella). They vary in size and number in different individuals. 3. Flat bones are thin, flattened, and usually a bit curved. The sternum (breastbone), scapulae (shoulder blades), ribs, and most skull bones are flat bones. Irregular bones have complicated shapes that fit none of the preceding classes. Examples include the vertebrae and the hip bones. FUNCTIONS OF BONES Besides contributing to body shape and form, our bones perform several important functions: SUPPORT. Bones provide a framework that supports the body and cradles its soft organs. For example, bones of lower limbs act as pillars to support the body trunk when we stand, and the rib cage supports the thoracic wall. 2. PROTECTION. The fused bones of the skull protect the brain. The vertebrae surround the spinal cord, and the rib cage helps protect the vital organs of the thorax. Musculoskeletal MOVEMENT. Skeletal muscles, which attach to bones by tendons, use bones as levers to move the body and its parts. As a result, we can walk, grasp objects, and breathe. The design of joints determine the types of movement possible. 4. MINERAL AND GROWTH FACTOR STORAGE. Bone is a reservoir for minerals, most importantly calcium and phosphate. The stored minerals are