Optometry Semester 1

OPTOMETRY · SEMESTER 1 Physiology Of Digestive System Human Anatomy and Physiology START READING NOTES Contents of This Topic LEARNING OUTCOMES INTRODUCTION FUNCTIONAL ANATOMY OF DIGESTIVE SYSTEM FUNCTIONAL ANATOMY OF DIGESTIVE SYSTEM CONT … WALL OF DIGESTIVE SYSTEM WALL OF DIGESTIVE SYSTEM CONT .. FOOD INTAKE REGULATION FUNCTIONS OF DIGESTIVE SYSTEM FUNCTIONS OF DIGESTIVE SYSTEM CONT … MECHANISM OF SWALLOWING/DEGLUTITION MECHANISM OF SWALLOWING/DEGLUTITION CONT … SALIVA FUNCTIONS OF SALIVA FUNCTIONS OF SALIVA CONT … REGULATION OF SALIVARY SECRETION REGULATION OF SALIVARY SECRETION CONT … THE STOMACH AND GASTRIC JUICE CELLS LINING STOMACH CELLS LINING STOMACH CONT … STRUCTRE NERVE SUPPLY TO THE STOMACH FUNCTIONS OF THE STOMACH GASTRIC JUICE FUNCTIONS OF GASTRIC JUICE FUNCTIONS OF GASTRIC JUICE CONT … FOOD DIGESTION IN THE STOMACH REGULATION OF GASTRIC JUICE SECRETION CEPHALIC PHASE GASTRIC PHASE INTESTINAL PHASE GASTRIC SECRETION INHIBITION BY GI HORMONES FACTORS INFLUENCING GASTRIC SECRETION PANCREATIC EXOCRINE SECRETIONS COMPOSITION OF PANCREATIC JUICE FUNCTIONS OF PANCREATIC JUICE REGULATION OF PANCREATIC JUICE SECRETION PHASES OF PANCREATIC JUICE SECRETION HORMONES THAT STIMULATE AND INHIBIT PANCREATIC SECRETION NEURAL REGULATION OF PANCREATIC JUICE SECRETION BILE SALTS FUNCTIONS OF BILE SALTS REGULATION OF BILE SALTS SECRETION FUNCTIONAL ANATOMY OF SMALL INTESTINE FUNCTIONS OF SMALL INTESTINE INTESTINAL VILLI AND GLANDS OF SMALL INTESTINE PROPERTIES AND COMPOSITION OF SUCCUS ENTERICUS FUNCTIONS OF SUCCUS ENTERICUS REGULATION OF SECRETION OF SUCCUS ENTERICUS FUNCTIONAL ANATOMY OF LARGE INTESTINE STRUCTURE OF WALL OF LARGE INTESTINE SECRETIONS OF LARGE INTESTINE FUNCTIONS OF LARGE INTESTINE ABSORPTION IN SMALL AND LARGE INTESTINE KEY ABSORBED SUBSTANCES IN SMALL INTESTINE KEY ABSORBED SUBSTANCES IN SMALL INTESTINE CONT … LARGE INTESTINE: WATER AND ELECTROLYTE RECLAMATION LARGE INTESTINE: WATER AND ELECTROLYTE RECLAMATION CONT … DEFECATION Physiology Of Digestive System PATHWAY FOR DEFECATION REFLEX WHEN YOU START EATING FOODS WITHOUT LABELS, YOU NO LONGER NEED TO COUNT CALORIES FOR PHYSIOLOGY OF DIGESTIVE SYSTEM LEARNING OUTCOMES BY THE END OF THIS SESSION STUDENTS MUST ABLE TO: Describe propulsive and mixing movements of the alimentary canal Describe the mechanism of swallowing(deglutition) Describe composition, functions and regulation of secretion of saliva Describe composition, functions and regulation of secretion of gastric juice Describe composition, functions and regulation of secretion of pancreatic juice Describe composition, functions and regulation of secretion of bile Describe composition, functions and regulation of secretion of the small intestines Describe absorption in the small and large intestines PART I INTRODUCTION Digestion is defined as the process by which food is broken down into simple chemical substances that can be absorbed and used as nutrients by the body. Digestive process is accomplished by mechanical and enzymatic breakdown of food into simpler chemical compounds. While the terms Alimentary Canal and Gastrointestinal (GI) Tract are often used interchangeably to refer to the Digestive System, it's important to understand the distinction: the alimentary canal and GI tract are actually components (building blocks) of the broader Digestive System. FUNCTIONAL ANATOMY OF DIGESTIVE SYSTEM Digestive system is made up of gastrointestinal tract (GI tract) or alimentary canal and accessory organs, which help in the process of digestion and absorption GI tract is a tubular structure extending from the mouth, pass through the thorax, abdomen and pelvis and ends at the anus, with a length of about 30 feet. It opens to the external environment on both ends. GI tract is formed by two types of organs: Primary digestive organs. Accessory digestive organs FUNCTIONAL ANATOMY OF DIGESTIVE SYSTEM CONT … Primary Digestive Organs :are the organs where actual digestion takes place. i. Mouth ii. Pharynx iii. Esophagus iv. Stomach v. Small intestine vi. Large intestine 2. Accessory Digestive Organs: are those which help primary digestive organs in the process of digestion. Accessory digestive organs are: i. Teeth ii. Tongue iii. Salivary glands iv. Exocrine part of pancreas v. Liver vi. Gallbladder. FUNCTIONAL ANATOMY OF DIGESTIVE SYSTEM CONT … WALL OF DIGESTIVE SYSTEM In general, wall of the GI tract is formed by four layers which are from inside out: 1. Mucosa layer (Mucus Layer) 2. Submucus layer 3. Muscular layer 4. Serosa (Serous) or fibrous layer WALL OF DIGESTIVE SYSTEM WALL OF DIGESTIVE SYSTEM 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) WALL OF DIGESTIVE SYSTEM CONT .. 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 loose connective tissue (visceral peritoneum) FOOD INTAKE REGULATION Food intake and energy expenditure are key regulators of body weight In humans, food intake is an essential function that is coordinated by the gastrointestinal, endocrine and nervous systems to maintain energy homeostasis The food intake cycle stages are hunger, satiation and satiety Hunger is the desire to eat and it is described as an uncomfortable emptiness in the abdomen. Satiation refers to the sensation of fullness that results in meal termination. Satiety is the term given to the postprandial events that determine the timing for the next meal FUNCTIONS OF DIGESTIVE SYSTEM Digestive system plays the major role in the digestion and absorption of food substances. Thus, the functions of digestive system include: Ingestion or consumption of food substances Breaking them into small particles by Mastication. Transport of small particles to different areas of the digestive tract through Propulsion. Secretion of necessary enzymes and other substances for digestion Digestion of the food particles Absorption of the digestive products (nutrients) Removal of unwanted substances from the body. FUNCTIONS OF DIGESTIVE SYSTEM CONT … Ingestion; taking in food into the stomach through the oral cavity, although liquid can be introduced directly into the stomach by nasogastric tube. Mastication; is the process by which food taken into the mouth is chewed by the teeth and broken down into small particles. Digestive enzymes cannot easily penetrate solid food particles

OPTOMETRY · SEMESTER 1 Body Fluids Human Anatomy and Physiology START READING NOTES Contents of This Topic BODY FLUIDS COMPARTMENT INTRODUCTION INTRODUCTION CONT … Body Water Content BODY FLUIDS Total Body Water Fluid Compartments Intracellular Fluid Compartment (ICF) FLUID COMPARTMENTS Fluid Compartments in the Human Body Intracellular Fluid Intracellular Fluid CONT … Extracellular Fluid Extracellular Fluid CONT … Extra Cellular Fluid Compartment (ECF) Blood Volume Composition of Body Fluids Composition of Body Fluids CONT … The Concentrations of Different Elements in Key Bodily Fluids PART II Fluid Movement between Compartments Fluid Movement between Compartments CONT … Capillary Exchange Capillary Exchange CONT … Exchange Between Plasma and ISF Exchange Between ECF and ICF PART III Solute Movement between Compartments Solute Movement between Compartments CONT … Facilitated Diffusion OF GLUCOSE Water Balance Water Balance CONT … Regulation of Water Intake Regulation of Water Intake CONT … Regulation of Water Output Regulation of Water Output CONT … Role of ADH Role of ADH CONT … Aquaporins diuretic ANY QUESTIONS? BODY FLUIDS COMPARTMENT BODY FLUIDS 1 INTRODUCTION Homeostasis, or the maintenance of constant conditions in the body, is a fundamental property of all living things. In the human body, the substances that participate in chemical reactions must remain within narrows ranges of concentration. Too much or too little of a single substance can disrupt your bodily functions. BODY FLUIDS 2 INTRODUCTION CONT … Because metabolism relies on reactions that are all interconnected, any disruption might affect multiple organs or even organ systems. Water is the most ubiquitous substance in the chemical reactions of life. The interactions of various aqueous solutions—solutions in which water is the solvent—are continuously monitored and adjusted by a large suite of interconnected feedback systems in your body. Understanding the ways in which the body maintains these critical balances is key to understanding good health. BODY FLUIDS 3 INTRODUCTION CONT … The chemical reactions of life take place in aqueous solutions. The dissolved substances in a solution are called solutes. In the human body, solutes vary in different parts of the body, but may include proteins—including those that transport lipids, carbohydrates, and, very importantly, electrolytes. Often in medicine, a mineral dissociated from a salt that carries an electrical charge (an ion) is called an electrolyte. For instance, sodium ions (Na+) and chloride ions (Cl-) are often referred to as electrolytes. BODY FLUIDS 4 INTRODUCTION CONT … In the body, water moves through semi-permeable membranes of cells and from one compartment of the body to another by a process called osmosis. Osmosis is basically the diffusion of water from regions of higher concentration of water to regions of lower concentration of water, along an osmotic gradient across a semi-permeable membrane. As a result, water will move into and out of cells and tissues, depending on the relative concentrations of the water and solutes found there. An appropriate balance of solutes inside and outside of cells must be maintained to ensure normal function. BODY FLUIDS 5 Body Water Content Human beings are mostly water, ranging from about 75 percent of body mass in infants to about 60 percent in adults, to as low as 45 percent in old age. The percent of body water changes with development, because the proportions of the body given over to each organ and to muscles, fat, bone, and other tissues change from infancy to adulthood. Your brain and kidneys have the highest proportions of water, which composes 80–85 percent of their masses. In contrast, teeth have the lowest proportion of water, at 8–10 percent. BODY FLUIDS 6 BODY FLUIDS 7 Total Body Water In normal adult human 70 kg Total body water = 60% of body weight = 42 liters (70*0.6) However, % can change depending on Age, sex, degree of obesity An increase in age is accompanied by increase in fat Hence % of body wt that is water decreases By age of 60 TBW = 50% of body wt in men BODY FLUIDS 8 Total Body Water Women have more fat Contain less water than men Total body water is 45 – 50% of body wt Children Neonate contain more water than adults (75 – 80% TBWt) By about 1 yr body water = 60% of body wt BODY FLUIDS 9 Fluid Compartments Intracellular Fluid Volume = 28 L, 2/3 TBW Interstitial Fluid Volume = 10.5 L, 75% of ECF Plasma Vol = 3.5 L, 25% of ECF BODY FLUIDS ICF (2/3 TBW) ECF (1/3 TBW) Total Body Water (TBW) 42 L, 60% of Body Wt 10 Intracellular Fluid Compartment (ICF) About 28 liters of the 42 liters are inside body cells ICF constitutes 40% of total body weight (for 70kg), or 2/3 of total body water (60% of body water) BODY FLUIDS 11 FLUID COMPARTMENTS EXTRACELLUAR FLUID INTRACELLULAR FLUID INTERSTITIAL FLUID PLASMA TRANSCELLULAR FLUID CSF Intra ocular Pleural Peritoneal Synovial Digestive Secretions BODY FLUIDS 12 Fluid Compartments Body fluids can be discussed in terms of their specific fluid compartment, a location that is largely separate from another compartment by some form of a physical barrier. The intracellular fluid (ICF) compartment is the system that includes all fluid enclosed in cells by their plasma membranes. Extracellular fluid (ECF) surrounds all cells in the body. Extracellular fluid has two primary constituents: the fluid component of the blood (called plasma) and the interstitial fluid (IF) that surrounds all cells not in the blood. BODY FLUIDS 13 FLUID COMPARTMENTS BODY FLUIDS 14 Fluid Compartments in the Human Body The intracellular fluid (ICF) is the fluid within cells. The interstitial fluid (IF) is part of the extracellular fluid (ECF) between the cells. Blood plasma is the second part of the ECF. Materials travel between cells and the plasma in capillaries through the IF. BODY FLUIDS 15 Intracellular Fluid The ICF lies within cells and is the principal component of the cytosol/cytoplasm. The ICF makes up about 60 percent of the total water in the human body, and in an average-size adult male, the ICF accounts for about 25

OPTOMETRY · SEMESTER 1 Blood Human Anatomy and Physiology START READING NOTES Contents of This Topic Overview Blood Composition Cells of the body are serviced by 2 fluids Blood The haematocrit Components of Blood Blood Plasma Plasma Constituents Formed Elements of Blood Erythrocytes (RBC) Erythrocytes Concentration of RBC in Blood Erythropoeisis Substances Required for Synthesis of RBC Genesis of RBC Myeloid stem cells give rise to RBCs, platelets, and all WBCs except for lymphocytes. Regulation of RBC Production Hemopoietic Growth Factors Role of erythropoeitin Regulation of Erythropoiesis Feedback Control of RBC Production Medical Uses of Growth Factors Formation of Haemoglobin Formation of haemoglobin Haemoglobin Iron Metabolism Transport of Iron Absorption of Iron Daily Loss of Iron Destruction of RBC Anaemia Blood Loss Anaema Aplastic anaemia Megaloblastic anaemia Haemolytic anaemia THE BLOOD Overview Blood Composition and functions Red blood cells: -Characteristics & functions, formation and destruction White blood cells: -Characteristics, functions, formation Platelets : -Haemostasis, fibrinolysis Blood groups and transfusion problems Blood Composition Blood Is an opaque, red liquid Consisting of several types of cells suspended in a complex, amber fluid Plasma Composed of Cells Plasma, liquid in which the cells are suspended The cells (formed elements) include Erythrocytes (RBCs) Leukocytes (WBCs) Platelets (cell fragments) The branch of science concerned with the study of blood, blood-forming tissues, and the disorders associated with them is called Hematology. Cells of the body are serviced by 2 fluids blood composed of plasma and a variety of cells transports nutrients and wastes interstitial fluid bathes the cells of the body Nutrients and oxygen diffuse from the blood into the interstitial fluid and then into the cells Wastes move in the reverse direction. Blood Its pH is 7.4 (7.35-7.45) 99% of the cells are RBC which are the O2 carrying cells of blood Blood is thicker (more viscous) than water and flows more slowly than water Average blood volume = 8% of body weight = 5.6L (70*0.08) On the average 60% of blood vol = plasma ( 3 liters) 40% of blood vol = RBC (2 liters) Values vary considerably in different people depending on sex and other factors The haematocrit Defined as the % of total blood that is erythocytes It is determined by centrifuging a sample of blood in a haematocrit tube Erythrocytes are forced to the bottom Plasma remains at the top Leucocyte and platelets form a thin layer in between Blood Plasma = 55% Leukocytes and platelets (buffy coat) RBC = 45% (Hct = 45%) Components of Blood Hematocrit 55% plasma 45% cells 99% RBCs < 1% WBCs and platelets Blood Plasma Non-cellular part of blood 0ver 90% water 7% plasma proteins created in liver confined to bloodstream albumin maintain blood osmotic pressure globulins (immunoglobulins) antibodies bind to foreignsubstances called antigens form antigen-antibody complexes fibrinogen for clotting 2% other substances electrolytes, nutrients, hormones, gases, waste products Plasma Constituents Constituent Functions 1 Water =92% of plasma wt Medium for carrying all other constituents 2 Electrolytes (inorganic) Total < 1% plasma wt Keep water in ECF, act as buffers, for blood clotting, for excitability of cells 3 Proteins 7% of plasma wt.= 7.3 g/100 ml Albumin, globulin, fibrinogen Provide non penetrating solute of plasma, Act as buffers, transport protein,clotting factors, enzymes, antibodies Blood Plasma Constituents Constituent Functions 4 Gases CO2, O2 CO2 is waste product, O2, for oxidative metabolism, 5 Nutrients Glucose, amino acids, lipids and cholesterol, vitamins, trace elements Nutrition Blood Plasma Constituents Constituent Functions 6 Waste products: urea, creatinine, uric acid, bilirubin 7 Individual hormnes Metabolic, Control system Blood Formed Elements of Blood Red blood cells ( erythrocytes ) White blood cells ( leukocytes ) Granular leukocytes neutrophils, eosinophils, basophils Agranular leukocytes lymphocytes = T cells, B cells, and natural killer cells monocytes Platelets (special cell fragments) Erythrocytes (RBC) Blood Erythrocytes Functions of RBC To transport Haemoglobin Hb carries O2 Hb carries O2 form lungs to tissue In lower animals Hb circulates as free protein in plasma In human being when it is free 3% leaks from capillaries Into tissue spaces; glomerular filtrate Erythrocytes Blood Hence for Hb to remain in blood stream It must exist inside the RBC Other functions of RBC include; Buffer function Contain carbonic Anhydrase which catalyze H2o + Co2 H2co3 Hco3- + H+ -Thus transport CO2 from tissues to lungs in the form of HCO3- Hb is an excellent acid/base buffer -Thus RBC are responsible for most buffering capacity of the blood Erythrocytes Blood Shape and size of RBC Biconcave discs Diameter = 7.8 µm Thickness at the thickest point = 2.5 µm average volume = 90 – 95 µ3 The shape of the RBC can change remarkably It is a bag which can be deformed To any shape; This allows it to pass through capillaries without problem Normal RBC Has great excess cell membrane for quantity inside Hence deformation does not stretch the membrane to cause it to rapture Concentration of RBC in Blood Blood In normal men average number of RBC Is 5,200,000 (+/- 300,000) per cubic ml In women average number of RBC Is 4,700,000 (+/- 300,000) Quantity of Hb in RBC When Hb formation is deficient in bone marrow % Of Hb in RBC may fall and volume of RBC may decrease Concentration of RBC in Blood Blood When Haematocrit = 40 – 45% Quantity of Hb in each cell is normal Whole blood of men contain 16 gm Hb/dl Whole blood of women contain 14 gm Hb/dl Each gram of pure Hb Combine with 1.39 ml of O2 Hence in normal man total amount carried Is = 1.39 * 16 = 21 ml of O2 per dl of blood In normal woman Is = 1.39 * 14 = 19 ml of O2 per dl of blood RBC have the ability to conc HB up to 34 g/dl Erythropoeisis Blood Sites of RBC production include York sack During early weeks of embryonic life Liver, spleen, lymph nodes Middle trimester Bone marrow Last trimester, after birth Bone marrow of all bones Up to

OPTOMETRY · SEMESTER 1 Blood Physiology Human Anatomy and Physiology START READING NOTES Contents of This Topic INTROD CONT … INTRODUCTION INTRODUCTION cont … COMPONENTS OF BLOOD COMPONENTS OF BLOOD CONT … BLOOD PLASMA Plasma proteins Plasma proteins CONT … Albumins Globulins BLOOD CELLS FUNCTIONS OF BLOOD CLASSIFICATION OF BLOOD CELLS RED BLOOD CELLS RED BLOOD CELLS CONT.. erythroPOIESIS SITES FOR ERYTHROPOIESIS erythroPOIESIS CONT… MATURATION OF ERYTHROCYTE Differentiation of Formed Elements from Stem Cells HAEMATOPIOESIS Hemopoietic Growth Factors Haemoglobin Control of erythropoiesis Control of erythropoiesis CONT … function of erythrocytes function of erythrocytes CONT … Destruction of erythrocytes Destruction of erythrocytes CONT .. Blood groups Blood groups CONT … The ABO system Leukocytes (white blood cells) Granulocytes (polymorphonuclear leukocytes) Neutrophils Neutrophils CONT … Eosinophils Eosinophils CONT … Basophils Agranulocytes Monocytes The monocyte–macrophage system The monocyte–macrophage system CONT .. Lymphocytes Examples of antigens include: Platelets (thrombocytes) Platelets (thrombocytes) CONT … Haemostasis 1 Vasoconstriction 2 Platelet plug formation 3 Coagulation (blood clotting) CLOTTING FACTORS CLOTTING FACTORS CONT … CLOTTING PATHWAYS BLOOD PHYSIOLOGY PART I INTROD CONT … BLOOD: Is a liquid connective tissue or viscous fluid that: Circulates in a virtually “CLOSED” system of blood vessels Blood, a connective tissue, that is composed of plasma and formed elements. INTRODUCTION Blood is a specialized body fluid that circulates through the cardiovascular system of humans and other vertebrates. It serves multiple critical functions, including the delivery of necessary substances such as oxygen and nutrients to cells, as well as the removal of metabolic waste products. INTRODUCTION cont … It circulates continually around the body, allowing constant communication between tissues distant from each other. Blood makes up about 7% of body weight (about 5.6 litres in a 70 kg man). This proportion is less in women and considerably greater in children, gradually decreasing until the adult level is reached. Blood in the blood vessels is always in motion because of the pumping action of the heart. INTRODUCTION cont … The continual flow maintains a fairly constant environment for body cells. Blood volume and the concentration of its many constituents are kept within narrow limits by homeostatic mechanisms. COMPONENTS OF BLOOD Composition of blood is divided into two aspects, the formed elements part and fluid part, namely; Blood Plasma (Fluid part) – occupies 55% of blood Blood Cells (Formed Element part) – occupies 45% of blood COMPONENTS OF BLOOD CONT … Blood is composed of a clear, straw-coloured, watery fluid called plasma in which several different types of blood cell are suspended. Plasma normally constitutes 55% of the volume of blood. The remaining 45% is accounted for by the cellular fraction of blood. The two fractions of blood, blood cells and plasma, can be separated by centrifugation (spinning) or by gravity when blood is allowed to stand. Because the cells are heavier than plasma, they sink to the bottom of any sample. BLOOD PLASMA Blood plasma is the liquid component of blood that constitutes approximately 55% of its total volume. It is a light amber-colored fluid that serves several critical functions in the body. Plasma is primarily composed of water (about 92%), with the remaining content consisting of plasma proteins, electrolytes, hormones, nutrients, and waste products. Plasma proteins Plasma proteins, which make up about 7% of plasma, are normally retained within the blood, because they are too big to escape through the capillary pores into the tissues. They are largely responsible for creating the osmotic pressure of blood, which keeps plasma fluid within the circulation. If plasma protein levels fall, because of either reduced production or loss from the blood vessels, osmotic pressure is also reduced, and fluid moves into the tissues (oedema) and body cavities. Plasma proteins CONT … Plasma Proteins include albumin, immunoglobulins, fibrinogen Plasma viscosity (thickness) is due to plasma proteins, mainly albumin and fibrinogen. Plasma proteins, with the exception of immunoglobulins, are formed in the liver. Albumins These are the most abundant plasma proteins (about 60% of total) and their main function is to maintain normal plasma osmotic pressure. Albumins also act as carrier molecules for free fatty acids, some drugs and steroid hormones. Globulins Their main functions are: as antibodies (immunoglobulins), which are complex proteins produced by lymphocytes that play an important part in immunity. They bind to, and neutralise, foreign materials (antigens) such as microorganisms. Transportation of some hormones and mineral salts, e.g. thyroglobulin carries the hormone thyroxineand transferrin carries the mineral iron inhibition of some proteolytic enzymes, e.g. α2 macroglobulin inhibits trypsin activity. BLOOD CELLS Blood cells are specialized cells produced through a process known as hematopoiesis, primarily found in the blood. They play crucial roles in various physiological functions, including oxygen transport, immune defense, and blood clotting. There are three main types of blood cells: Red blood cells (erythrocytes) White blood cells (leukocytes) Platelets (thrombocytes). SUMMARY OF BLOOD CONSTITUENTS FUNCTIONS OF BLOOD The major functions of blod includes; Oxygen Transport Nutrient Distribution Waste Removal Hormone Transport Temperature Regulation pH Balance Fluid Balance Immune Response Clotting Mechanism CLASSIFICATION OF BLOOD CELLS Blood cells can be classified into three main types: red blood cells, white blood cells, and platelets. Each type has distinct functions and characteristics. RED BLOOD CELLS Red blood cells are the most abundant type of blood cell, accounting for approximately 40 to 45 percent of the blood’s volume. Their primary function is to transport oxygen from the lungs to the body’s tissues and return carbon dioxide from the tissues back to the lungs for exhalation. Red blood cells contain hemoglobin, a protein that binds oxygen and gives blood its red color. They are characterized by their biconcave disk shape, which allows for flexibility as they navigate through various sizes of blood vessels. RED BLOOD CELLS CONT.. Red blood cells are biconcave discs; they have no nucleus, and their diameter is about 7 micrometres. Their main function is in gas transport, mainly of oxygen, but they also carry some carbon dioxide. Their characteristic shape is suited to their purpose; the biconcavity increases their surface area for gas

OPTOMETRY · SEMESTER 1 Haemostasis Human Anatomy and Physiology START READING NOTES Contents of This Topic Response to Blood Vessel Injury Haemostasis: In general, blood clotting occurs in three stages: 1. FORMATION OF PROTHROMBIN ACTIVATOR Intrinsic pathway 2. CONVERSION OF PROTHROMBIN ANTICLOTTING MECHANISM IN THE BODY Chemical Factors – Natural Anticoagulants Response to Blood Vessel Injury Haemostasis: Haemostasis: The process of forming clots in the walls of damaged blood vessels and preventing blood loss while maintaining blood in a fluid state within the vascular system. or.defined as the process in which blood loses its fluidity and becomes a jelly-like mass. A collection of complex interrelated systemic mechanisms operates to maintain this balance between coagulation and anticoagulation. When a small blood vessel is damaged, the injury initiates a series of events that lead to the formation of a clot (haemostasis). This seals off the damaged region and prevents further blood loss In general, blood clotting occurs in three stages: 1. Formation of prothrombin activator 2. Conversion of prothrombin into thrombin 3. Conversion of fibrinogen into fibrin. 1. FORMATION OF PROTHROMBIN ACTIVATOR Blood clotting commences with the formation of a substance called prothrombin activator, which converts prothrombin into thrombin. Its formation is initiated by substances produced either within the blood or outside the blood. Thus, formation of prothrombin activator occurs through two pathways: i. Intrinsic pathway ii. Extrinsic pathway. Intrinsic pathway In this pathway, the formation of prothrombin activator is initiated by platelets, which are within the blood itself Extrinsic pathway. In this pathway, the formation of prothrombin activator is initiated by the tissue thromboplastin, which is formedfrom the injured tissues. 2. CONVERSION OF PROTHROMBIN INTO THROMBIN Prothrombin activator that is formed in intrinsic and extrinsic pathways converts prothrombin into thrombin 3. CONVERSION OF FIBRINOGEN INTO FIBRIN The final stage of blood clotting involves the conversion of fibrinogen into fibrin by thrombin. ANTICLOTTING MECHANISM IN THE BODY Under physiological conditions, intravascular clotting does not occur. It is because of the presence of some physicochemical factors in the body Physical Factors i. Continuous circulation of blood. ii. Smooth endothelial lining of the blood vessels Chemical Factors – Natural Anticoagulants i. Presence of natural anticoagulant called heparin that is produced by the liver iii. All the clotting factors are in inactive state. ← PREVIOUS TOPICNEXT TOPIC →VIEW MODULE NOTESVIEW SEMESTER NOTESALL OPTOMETRY NOTES Need These Notes as PDF? Request a formatted copy for offline study, printing or revision. GET PDF NOTES ON WHATSAPP

OPTOMETRY · SEMESTER 1 Muscles Of The Head And Neck Human Anatomy and Physiology START READING NOTES Contents of This Topic MUSCLES OF THE HEAD MUSCLE OF SCALP THE SCALP: OCCIPITOFRONTALIS MUSCLES OF FACIAL EXPRESSION ORBITAL GROUP ORBICULARIS OCULI CORRUGATOR SUPERCILII NASAL GROUP NASALIS ALAR PART OF THE NASALIS PROCERUS DEPRESSOR SEPTI NASI ORAL GROUP THE ORBICULARIS ORIS BUCCINATOR DEPRESSOR ANGULI ORIS DEPRESSOR LABII INFERIORIS MENTALIS RISORIUS ZYGOMATICUS MAJOR AND ZYGOMATICUS MINOR LEVATOR LABII SUPERIORIS LEVATOR LABII SUPERIORIS ALAEQUE NASI LEVATOR ANGULI ORIS MASSETER TEMPORALIS LATERAL PTERYGOID (TWO MEDIAL PTERYGOID (TWO INTRODUCTION ANTERIOR TRIANGLE. MUSCLES OF THE ANTERIOR TRIANGLE OF THE NECK SUPRAHYOID MUSCLES INFRAHYOID MUSCLES ANTEROLATERAL NECK MUSCLE MUSCLES OF THE HEAD AND NECK MUSCLES OF THE HEAD MUSCLES OF THE HEAD Grouped into: Muscle of Scalp Muscles of Facial Expression Muscles of Mastication MUSCLE OF SCALP THE SCALP: The scalp consists of five layers. the first three of which are intimately bound together and move as a unit. To assist one in memorizing the names of the five layers of the scalp, use each letter of the word SCALP to denote the layer of the scalp. Skin: which is thick and hair bearing and contains numerous sebaceous glands Connective tissue Beneath the skin. The fibrous septa uniting the skin to the underlying aponeurosis of the occipitofrontalis muscle. Numerous arteries and veins are found in this layer. Aponeurosis (epicranial), which is a thin, tendinous sheet that unites the occipital and frontal bellies of the occipitofrontalis muscle. THE SCALP: Loose areolar tissue: Occupies the subaponeurotic space. Loosely connects the epicranial aponeurosis to the periosteum of the skull (the pericranium). The areolar tissue contains a few small arteries, but it also contains some important emissary veins OCCIPITOFRONTALIS Consist of two bells: Occipital belly Frontal belly OCCIPITAL BELLY ORIGIN: Highest nuchal line of occipital bone INSERTION: Epicranial aponeurosis NERVE SUPPLY: Facial nerve FUNCTION: Moves scalp on skull and raises eyebrows FRONTAL BELLY ORIGIN: Skin and superficial fascia of eyebrows INSERTION: Epicranial aponeurosis NERVE SUPPLY: Facial nerve FUNCTION: Moves scalp on skull and raises eyebrows MUSCLES OF FACIAL EXPRESSION MUSCLES OF FACIAL EXPRESSION These are muscles of the face. Because these muscles control expressions of the face, they are sometimes referred to as muscles of "FACIAL EXPRESSION." They also act as sphincters and dilators of the orifices of the face (i.e., the orbits, nose, and mouth). ORBITAL GROUP orbicularis oculi and the corrugator supercilii. ORBICULARIS OCULI The orbicularis oculi is a muscle in the face that closes the eyelids. It consist of: Palpebral part. Orbital part. PALPEBRAL PART ORIGIN: Medial palpebral ligament INSERTION: Lateral palpebral raphe NERVE SUPPLY: Facial nerve FUNCTION: Closes eyelids and dilates lacrimal sac ORBICULARIS OCULI ORBITAL PART. thicker and of a reddish color ORIGIN: Medial palpebral ligament and adjoining bone INSERTION: Loops return to origin NERVE SUPPLY: Facial nerve FUNCTION: Throws skin around orbit into folds to protect eyeball CORRUGATOR SUPERCILII The second muscle in the orbital group. Much smaller. Found deep to the eyebrows and the orbicularis oculi muscle and is active when frowning. ORIGIN: Superciliary arch INSERTION: Skin of eyebrow NERVE SUPPLY: Facial nerve FUNCTION: It draws the eyebrows toward the midline, causing vertical wrinkles above the nose. NASAL GROUP NASALIS, THE PROCERUS, AND DEPRESSOR SEPTI NASI NASALIS The largest and best developed of the muscles of the nasal group Active when the nares are flared It consists of: transverse part (the compressor naris) alar part (the dilator naris) TRANSVERSE PART OF THE NASALIS: ORIGIN: Frontal process of maxilla INSERTION: Aponeurosis of bridge of nose NERVE SUPPLY: Facial nerve FUNCTION: Compresses mobile nasal cartilages ALAR PART OF THE NASALIS ORIGIN: Maxilla INSERTION: Ala of nose NERVE SUPPLY: Facial nerve FUNCTION: Widens nasal aperture PROCERUS Small muscle superficial to the nasal bone Active when an individual frowns ORIGIN: Nasal bone INSERTION: Skin between eyebrows NERVE SUPPLY: Facial nerve FUNCTION: Wrinkles skin of nose WRINKLE ON SKIN OF NOSE DEPRESSOR SEPTI NASI ORIGIN: Maxilla INSERTION: Lower part of the nasal septum NERVE SUPPLY: Facial nerve FUNCTION: Pulls the nose inferiorly. Assisting the alar part of the nasalis in opening the nares. ORAL GROUP Orbicularis oris. Buccinators. Lower group of muscles (depressor anguli oris, depressor labii inferioris and mentalis) Upper group of muscles (risorius, zygomaticus major, zygomaticus minor, levator labii superioris, levator labii superioris alaeque nasi, and levator anguli oris) THE ORBICULARIS ORIS Complex muscle consisting of fibers that completely encircle the mouth, Originate near the midline from the maxilla superiorly and the mandible inferiorly. It inserts into the skin and mucous membrane of the lips. Function is apparent when pursing the lips, as occurs during whistling. Contraction of the orbicularis oris narrows the mouth and closes the lips. BUCCINATOR The buccinator forms the muscular component of the cheek. It is in the space between the mandible and the maxilla. The buccinator arises from the posterior part of the maxilla and mandible opposite the molar teeth and the pterygomandibular raphe. Contraction of the buccinator presses the cheek against the teeth. This keeps the cheek taut and aids in mastication by preventing food from accumulating between the teeth and the cheek. Assists in the forceful expulsion of air from the cheeks. LOWER GROUP OF ORAL MUSCLES DEPRESSOR ANGULI ORIS Is active during frowning. It arises along the side of the mandible below the canine, premolar, and first molar teeth. Inserts into skin and the upper part of the orbicularis oris near the corner of the mouth. FUNCTION: It depresses the corner of the mouth. DEPRESSOR LABII INFERIORIS Depressor labii inferioris arises from the front of the mandible, deep to depressor anguli oris. Inserting into the lower lip. It depresses the lower lip and moves it laterally. MENTALIS It is the deepest muscle of the lower group, Arising from the mandible just inferior to the incisor teeth. Insert into the skin of the chin. FUNCTION It raises and protrudes the lower lip as it wrinkles the skin of the chin. Helps position the lip when drinking from a cup or when

OPTOMETRY · SEMESTER 1 Vertebral Column: Structure and Function Human Anatomy and Physiology START READING NOTES Contents of This Topic Structural organization and functions of vertebral column Objectives Vertebral column Figure1: Parts of A Typical Vertebra The Vertebral Column(1) The Vertebral Column(2) The Vertebral Column(3) Curvatures of Vertebral Column(1) Curvatures of Vertebral Column(2) Curvatures of Vertebral Column(3) Curvatures of Vertebral Column(4) Curvatures of Vertebral Column(5) Structure of intervertebral Disc(1) Structure of intervertebral Disc(2) Structure of intervertebral Disc(3) Function of the intervertebral Disc(1) Function of the intervertebral Disc(2) Structure of Vertebrae(1) Structure of Vertebrae(2) Structure of Vertebrae(3) Structure of Vertebrae(4) Structure of Vertebrae(5) Structure of Vertebrae(6) Seven Processes Arise From the Vertebral Arch of a Typical Vertebra(1) Seven Processes Arise From the Vertebral Arch of a Typical Vertebra(2) Functions of the Vertebral Column Characteristics of typical cervical vertebrae(1) Characteristics of typical cervical vertebrae(2) Characteristics of typical cervical vertebrae(3) Characteristics of the atypical cervical Vertebrae (1) Characteristics of the atypical cervical Vertebrae (2) Characteristics of the atypical cervical Vertebrae (3) Characteristics of Thoracic Vertebrae(1) Characteristics of Thoracic Vertebrae(2) Characteristics of lumbar Vertebrae Sacrum and Cocygeal Vertebrae Key Points Evaluation Structural organization and functions of vertebral column 1 Objectives Explain vertebral column curvatures Describe structure and function of vertebrae 2 Vertebral column 3 Vertebral column 4 Figure1: Parts of A Typical Vertebra 5 The Vertebral Column(1) The vertebral column is the central bony pillar of the body The adult vertebral column typically consists of 33 vertebrae arranged in five regions: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal. The typical vertebrae consists of Body, transverse process, the foramen transversarium, the vertebral foramen and spinous process 6 The Vertebral Column(2) The vertebral column (spine), extending from the cranium (skull) to the apex of the coccyx. The vertebral column: protects the spinal cord and spinal nerves supports the weight of the body superior to the level of the pelvis provides a partly rigid and flexible axis for the body and a pivot for the head and plays an important role in posture and locomotion. Significant motion occurs between only the superior 25 vertebrae 7 The Vertebral Column(3) The 5 sacral vertebrae are fused in adults to form the sacrum, and the 4 coccygeal vertebrae are fused to form the coccyx The vertebrae gradually become larger as the vertebral column descends to the sacrum and then become progressively smaller toward the apex of the coccyx These structural differences are related to the fact that the successive vertebrae bear increasing amounts of the body's weight 8 Curvatures of Vertebral Column(1) 9 10 Curvatures of Vertebral Column(2) The vertebral column in adults has four curvatures: cervical, thoracic, lumbar, and sacral The curvatures provide a flexible support (shock-absorbing resilience) for the body. The thoracic and sacral (pelvic) curvatures (kyphoses) are concave anteriorly, whereas the cervical and lumbar curvatures (lordoses) are concave posteriorly. 11 Curvatures of Vertebral Column(3) The thoracic and sacral curvatures are primary curvatures, developing during the fetal period. Primary curvatures are retained throughout life as a consequence of differences in height between the anterior and the posterior parts of the vertebrae. The cervical and lumbar curvatures are secondary curvatures, which begin to appear in the cervical region during the fetal period but do not become obvious until infancy. 12 Curvatures of Vertebral Column(4) Secondary curvatures are maintained primarily by differences in thickness between the anterior and the posterior parts of the IV discs The cervical curvature becomes prominent when an infant begins to hold his or her head erect The lumbar curvature becomes obvious when an infant begins to walk and assumes the upright posture This curvature, generally more pronounced in females, ends at the lumbosacral angle, formed at the junction of the L5 vertebra with the sacrum. 13 Curvatures of Vertebral Column(5) The sacral curvature of females is reduced so that the coccyx protrudes less into the pelvic outlet. The curvatures provide additional flexibility (shock-absorbing resilience) to the vertebral column, augmenting that provided by the IV discs 14 Structure of intervertebral Disc(1) The intervertebral discs are the main structures that bind together the vertebral bodies, and they extend from C2 to the sacrum (C1 has no vertebral body) The discs are responsible for one quarter of the length of the vertebral column below the level of C2 They are thickest in the cervical and lumbar regions, where the movements of the vertebral column are greatest They may be regarded as semielastic discs, which lie between the rigid bodies of adjacent vertebrae Their physical characteristics permit them to serve as shock absorbers when the load on the vertebral column is suddenly increased, as when one is jumping from a height. 15 Structure of intervertebral Disc(2) Their elasticity allows the rigid vertebrae to move one on the other Unfortunately, their resilience is gradually lost with advancing age Each disc consists of a peripheral part, the anulus fibrosus, and a central part, the nucleus pulposus The anulus fibrosus is composed of fibrocartilage, in which the collagen fibers are arranged in concentric layers or sheets The nucleus pulposus in children and adolescents is an ovoid mass of gelatinous material containing a large amount of water, a small number of collagen fibers, and a few cartilage cells. It is normally under pressure and situated slightly nearer to the posterior than to the anterior margin of the disc 16 Structure of intervertebral Disc(3) No discs are found between the first two cervical vertebrae or in the sacrum or coccyx 17 Function of the intervertebral Disc(1) The semifluid nature of the nucleus pulposus allows it to change shape and permits one vertebra to rock anteriorly or posteriorly on another, as in flexion and extension of the vertebral column A sudden increase in the compression load on the vertebral column causes the semifluid nucleus pulposus to become flattened. The outward thrust of the nucleus is accommodated by the resilience of the surrounding annulus fibrosus Sometimes, the outward thrust is too great for the anulus fibrosus and it ruptures, allowing the

OPTOMETRY · SEMESTER 1 Blood and Blood forming organs introduction Human Anatomy and Physiology START READING NOTES Contents of This Topic Mention constituent of blood Blood is the body’s only fluid tissue, It is composed of liquid plasma and formed elements The blood components. The liquid component of blood is called plasma, a mixture of water, sugar, fat, protein, and salts. Constituents of plasma: Clotting factors If whole blood is allowed to clot and the clot is removed, the remaining fluid is called serum Plasma Proteins – constitute 7-9% of the plasma Plasma Proteins Most of Gamma globulins are immunoglobulins; Functions of Plasma Clotting factor (fibrinogen) plays a key role in the clotting of blood Blood Cells. Blood cells.. Formed elements Production of Red Blood Cells Erythrocytes (RBCs) RBCs Is the process of red blood cell formation Red Blood Cells (3) FACTORS NECESSARY FORERYTHROPOIESIS GENERAL FACTORS MATURATION FACTORS FACTORS NECESSARY FOR HEMOGLOBIN FORMATION Haemoglobin (1) ANAEMIA They are also known as leukocytes or leucocytes White Blood Cells (1) White Blood Cells (2) Classification of Leucocytes Classification of Leucocytes (2) Neutrophils (2) Eosinophils Basophils Macrophages (1) Macrophages (2) Lymphocyte B-lymphocytes (B cells) Platelets (thrombocyte) Production of Platelets Platelets (Thrombocytes) (3) Functions of blood… Functions of blood. Functions of blood.. References. Mention constituent of blood Classify blood cells Outline sites for the synthesis of blood cells Describe requirements for production of blood cells Describe functions of blood cells Describe metabolism of haemoglobin Describe blood typing and transfusion Describe mechanism of blood coagulation(haemostasis) Blood and blood forming organs Blood is the body’s only fluid tissue, It is composed of liquid plasma and formed elements Formed elements include: Erythrocytes(RBCs), Leukocytes(WBCs), Platelets Blood and blood forming organs The blood components. Blood and blood forming organs The liquid component of blood is called plasma, a mixture of water, sugar, fat, protein, and salts. It makes up about 55% of total blood volume Blood and blood forming organs Constituents of plasma: It is mostly water – 92% by volume Dissolved proteins (plasma proteins) Albumin (60%) Globulin (36%) Fibrinogen (4%) Nutrients (glucose, amino acids, fats, salts, minerals, etc.) Blood and blood forming organs Clotting factors Electrolytes (Na+, Ca2+, Mg2+, HCO3-, Cl- etc.) Hormones Antibodies Waste products of metabolism (CO2, lactic acid, urea, uric acid, creatinine, etc.) If whole blood is allowed to clot and the clot is removed, the remaining fluid is called serum Blood and blood forming organs serum clot Plasma Proteins – constitute 7-9% of the plasma Albumins (60% – 80%) Produced by the liver, Provide the osmotic pressure which is necessary to maintain blood volume and pressure. Blood and blood forming organs Plasma Proteins Globulins, divided into three types: Alpha and beta globulin, produced by the liver and function to transport lipids and fat soluble vitamins in the blood. Gamma globulins are antibodies produced by lymphocytes and function in immunity. Blood and blood forming organs Most of Gamma globulins are immunoglobulins; IgA IgD IgE IgG- 3/4 of all immunoglobulins IgM Blood and blood forming organs Functions of Plasma Serves as the protein reserve of the human body Albumin maintains the colloid osmotic pressure, which regulates the movement of water between blood and tissue Albumin transports bilirubin, fatty acids and some drugs Protects the body from infection and other blood disorders Clotting factor (fibrinogen) plays a key role in the clotting of blood Transports nutrients and gases Transports metabolic waste products Blood and blood forming organs Blood Cells. Red blood cells (RBC) a.k.a erythrocytes) White blood cells (WBC), leucocytes Platelets (thrombocytes). Blood and blood forming organs Blood cells.. Formed elements Erythrocytes, leukocytes, and platelets make up the formed elements Only WBCs are complete cells, RBCs have no nuclei or organelles, and platelets are just cell fragments Most formed elements survive in the bloodstream for only a few days, Most blood cells do not divide but are renewed by cells in bone marrow Blood and blood forming organs Production of Red Blood Cells Areas of the Body That Produce Red Blood Cells. In the early weeks of embryonic life, primitive, nucleated RBC are produced in the yolk sac. During the middle trimester of gestation, the liver is the main organ for production of RBC but reasonable numbers are also produced in the spleen and lymph nodes. Blood and blood forming organs Production of Red Blood Cells Then, during the last month or so of gestation and after birth, red blood cells are produced exclusively in the bone marrow. Blood and blood forming organs Erythrocytes (RBCs) Biconcave discs, anucleate, essentially no organelles Filled with hemoglobin (Hb), a protein that functions in gas transport. Contain the plasma membrane protein spectrin and other proteins that: Give erythrocytes their flexibility Allow them to change shape as necessary Blood and blood forming organs RBCs Biconcave disk shape of the RBC Blood and blood forming organs Is the process of red blood cell formation Blood and blood forming organs Red Blood Cells (3) Synthesis of RBC needs iron, folic acid, vitamin B12, manganese, iodine, erythropoietin and protein Erythropoietin hormone (EPO) secreted by kidneys, is a glycoprotein that serves as the primary regulator of red blood cells Blood and blood forming organs FACTORS NECESSARY FORERYTHROPOIESIS Development and maturation of erythrocytes require variety of factors, which are classified into three categories: 1. General factors 2. Maturation factors 3. Factors necessary for hemoglobin formation. Blood and blood forming organs GENERAL FACTORS General factors necessary for erythropoiesis are: i. Erythropoietin hormone ii. Thyroxine iii. Hemopoietic growth factors iv. Vitamins. Blood and blood forming organs MATURATION FACTORS Vitamin B12, intrinsic factor and folic acid are necessary for the maturation of RBCs. Blood and blood forming organs FACTORS NECESSARY FOR HEMOGLOBIN FORMATION First class proteins and amino acids Iron Copper Cobalt and nickel Vitamins Blood and blood forming organs Haemoglobin (1) Haemoglobin (Hb or Hgb) is the iron-containing oxygen-transport substance in the red blood cells The adult haemoglobin (HbA) molecule is made up of four chains 2 alpha chains and 2 beta chains (α2 β2) The fetal haemoglobin

OPTOMETRY · SEMESTER 1 Skull: Structure and Function Human Anatomy and Physiology START READING NOTES Contents of This Topic bony function of the the of The Eight bones (i) FRONTAL : The (ii) OCCIPITAL : The (iii) SPHENOID : The (iv) ETMOID : The (v) PARIETAL : The (vi) TEMPORAL : There are 14 bones in the (i) ZYGOMATIC : The (ii) LACRIMAL : (iii) NASAL : The (iv) INFERIOR (v) PALATINE: The (vi) VOMER: The (vii) MAXILLA: The (viii) MANDIBLE: External Surface of Cranial Base The alveolar arch of the maxillae (supporting the maxillary teeth), Skull: Structure and Function CT Internal Surface of Cranial Base The Anterior Cranial Fossa The Middle Cranial Fossa The Posterior Cranial Fossa Boundaries Function of the Skull 5. Facilitate breathing by bone of nasal cavities SKULL-STRUCTURES AND FUNCTIONS bony that its hape.  Skull is the framework, gives the head, characteristic s function of the protect and the tissues of rly the The skull is to the soft vital the head, particula brain. the The Skull consists of Cranium bony box housing the brain) and face. of in cranium the The skull is composed 22 bones, the and 14 in face. 8 The Eight bones (1) Frontal (2) Occipital (3) Sphenoid (4) Ethmoid of the Cranium are :- (5) Two Parietal bones (6) Two Temporal bones (i) FRONTAL : The frontal bone forms the forehead , the anterior (front) part of the cranial vault and the roof of the orbits (eye sockets). Inside the bone, just behind the eyebrows are the frontal sinuses. two air spaces called (ii) OCCIPITAL : The occipital bone forms the posterior (back) part of the floor and vault of the cranium. It is the bone which supports the head upon the spinal column. The spinal cord leaves the cranium through an opening in the occipital bone called the foramen magnum (iii) SPHENOID : The sphenoid bone is the central part of the base of the cranium. It forms part of the orbits, transmits the optic nerve and supports the posterior part of the maxilla. The sphenoid air sinuses lie in this bone. The pituitary gland lies in a bony socket called the sella turcica, located on the superior aspect of the sphenoid bone. Dental Tip: When a patient is seated in the dental chair, the headrest should support the occipital bone and thereby support the entire head. (iv) ETMOID : The Ethmoid bone lies between the eyes and extends from the frontal bone to the sphenoid bone. It forms the anterior part of the skull, the medial wall of each orbit, part of the nasal septum and the roof of the nose. It transmits the olfactory smell) nerve (nerve of (v) PARIETAL : The Parietal bones forms large part of the a cranial extend frontal vault and from the bone to the occipital bone. The two bones join at the midline on the top of the cranium and form the saggital suture. From this suture, these bones extend down and out to about the level of the top of the external ear where they meet the temporal bones. (vi) TEMPORAL : Temporal bones complete the sides and part of the base of the cranium. These bones contain organs of hearing and equilibrium. The external acoustic meatus in the side of each bone forms a passage from the external ear to the middle ear which lies within each bone. There are 14 bones in the (i) Mandible (1) (ii) Maxillae (2) (iii) Zygomatic Bones (2) (iv) Lacrimal Bones (2) (v) Nasal Bones (2) (vi) Inferior conchae (2) (vii) Palatine Bones (2) (viii) Vomer (1) face. (i) ZYGOMATIC : The right and left zygomatic bones form the lower and outer edges of each orbit and that part of each zygomatic arch nearest the eye. The Zygomatic bone and Zygomatic process of the temporal bone form the Zygomatic arch. The anterior edge of the zygomatic bone joins the maxilla. That part of the maxilla which joins the zygomatic bone is called the zygomatic process. (ii) LACRIMAL : The paired (right and left) Lacrimal bones form small parts of the medial walls the orbits. of The lacrimal bones transmits the naso-lacrimal duct from the eye to the nose or nasal fossa. (iii) NASAL : The nasal bones (right and left) are long, thin pieces of bone that form the upper part of the bridge of the nose. The anterior lower part cartilage of the nasal septum is composed of (iv) INFERIOR CONCHAE: The inferior nasal conchae (right and left) are scroll like bones lying horizontally along the lateral walls of the nasal cavity. The bony elements of the middle and superior conchae are extensions of the lateral parts of the ethmoid bones. (v) PALATINE: The palatine bones (right and left) join in the midline to form the posterior part of the palate . hard Palatine bones also form part of the floor and lateral walls of the nasal cavity and part of the floor of the orbits. (vi) VOMER: The vomer forms the inferior part of the nasal septum, the vertical partition separating the right and left nasal cavities. (vii) MAXILLA: The right and left maxillary bones forms the upper jaw and palate of the mouth. The two halves are fused form the upper jaw. at the intermaxillary suture to (viii) MANDIBLE: The horse shoe- shaped bone forming the lower jaw, articulating with the skull at the temporomandi – -bular joint. Mandible is the largest, strongest face. and lowest bone in the External Surface of Cranial Base The external aspect of the cranial base or basicranium features……. The alveolar arch of the maxillae (supporting the maxillary teeth), The palatine processes of the maxillae, The palatine, Sphenoid, Vomer, Temporal Occipital bones. Skull: Structure and Function The hard palate (bony palate) is formed by the palatine processes of the maxillae anteriorly and the horizontal plates of the palatine bones posteriorly. Skull: Structure and Function Depressions in the squamous part of the temporal bone, called