Anatomy Theoretical Mansoura University 2024-2025 PDF

Mansoura National University Faculty of Nursing ANATOMY Theoretical FIRST LEVEL FIRST SEMSETER ACADEMIC YEAR 2024-2025 Mansoura University Faculty of Nursing First year / First Semester Anatomy Dr. Raouf Fekry Professo...

Mansoura National University Faculty of Nursing ANATOMY Theoretical FIRST LEVEL FIRST SEMSETER ACADEMIC YEAR 2024-2025 Mansoura University Faculty of Nursing First year / First Semester Anatomy Dr. Raouf Fekry Professor of Anatomy Faculty of Medicine, Mansoura University 2024 / 2025 1  Preface Human Anatomy forms the basis for the practice of medicine. Anatomy leads the physician towards an understanding of a patient's disease. Human Anatomy text was written to serve as a foundation and resource for students pursuing health-related careers in fields such as medicine, dentistry, nursing, physician assistant, medical technology, physical therapy, massage therapy, and other health related professions. The ability to interpret a clinical observation correctly is the endpoint of a sound anatomical understanding. The focus of Human Anatomy is to provide applicable knowledge of the structure of the human body. Practical information is presented in this text that will enable students to apply facts to the real- world situations they might encounter in theirprofession. The main objective of this course is to provide a text that is inviting and attractive and up-to-date information of practical concern. It aims to entice readers to study the material and thereby enhance their appreciation of life through a better understanding of the structure, function, and magnificence of their own bodies 2  ANATOMY Anatomy:The term anatomy is derived from a Greek word meaning “to cut up”. It is the study of the structure of the body and the relationship of its parts to eachother. 1- Anatomicalposition The anatomical position is the standard reference position of the body used to describe the location of structures The body is in erect posture with the feet close to each other and theface directedforwards. The upper limbs are straight by the sides with palms facing forward. Fig: Anatomical position 3 2- Anatomicalplanes 1) Sagittalplane: Is a vertical plane which divides the body into right and leftparts. Median sagittalplane: Is the plane passing through the centerof the body dividing it into right & lefthalves. Parasagittalplane: Plane lying to one or the other sideof median plane & parallel toit. It divides the body into unequalparts 2) Coronalplane: A vertical plane divides the body into anterior and posteriorparts. 3) Transverseplane: A horizontal plane divides the body into upper (cranial) and lowers (caudal)parts. Fig: the anatomical planes 4 3- Anatomicalterms I - Terms related toposition ▪ Superior: Toward thehead. ▪ Inferior: Toward thefeet. ▪ Anterior: Toward the front of thebody. ▪ Posterior: Toward the back of thebody. ▪ Median: At the middle line of thebody. ▪ Medial: Toward the midline of thebody. ▪ Lateral: Toward the side of thebody. ▪ Superficial: Toward the surface of thebody. ▪ Deep: Away from the surface of thebody. ▪ Proximal: Toward the root oflimb E.g. the arm is proximal to theforearm. ▪ Distal: Away from the root oflimb ▪ E.g. the hand is distal to theforearm. ▪ Internal: Inside an organ orcavity. ▪ External: Outside an organ orcavity. 5  Fig: Anatomical terms related to position II - Terms related tomovements 1. Flexion: a bending movement around a joint that decreases the angle between the two articulatingbones. 2. Extension: an unbending movement around a joint that increases the angle between the two articulatingbones. 3. Abduction: movement away from the midline of thebody. 4. Adduction: movement toward the midline of the bodyplane. 5. Rotation: Is the movement of a part of the body around its longitudinalaxis. 6  ▪ Medial rotation: rotation a part of the body around its longitudinal axis towards themidline ▪ Lateral rotation: rotation a part of the body around its longitudinal axis away frommidline. 6. Circumduction: movement of a limb or extremity so that the distal end describes a circle, it is successive movement of flexion, abduction, extension andadduction. 7.Protraction and retraction: Are mostly used to describe the forward and backward movement of the mandible at the tempro- mandibularjoint. ▪ Protraction: Is to moveforward. ▪ Retraction: Is to movebackward. 7 Fig : Anatomical terms related to movement 8 4- Bodyorganization ▪ The body of the living organism consists of manysystems. ▪ Each system is formed of manyorgans. ▪ Each organ is formed of manytissues. ▪ Each tissue is formed of layers or groups of similar cells that perform a commonfunction. ▪ The cell is the basic structural and functional component of the body. Each cell is composed of cytoplasm and nucleus and is surrounded by cellmembrane. Fig: Body organization 9 5- Bodyregions The human body is divided into several regions that can beidentified on the surface of the body. The major body regionsare the head, neck, trunk, upper extremity, and lower extremity. The trunk is frequently divided into the thorax, abdomen, and pelvis. 6- Bodysystems The main systems of the human body are as follows: 1- Cardiovascular / Circulatorysystem: It is responsible for delivering oxygen and nutrients to organs and cells and carrying their waste products away. 2- Digestivesystem: It is responsible for digestion and absorption of the nutrients and elimination of the waste from the body. 3- Endocrinesystem: It provides chemical communications within the body using hormones. 4- Integumentarysystem: It includes skin, and its appendages (hair, nail). 5- Lymphaticsystem: It defends the body against disease-causing agents. 6- Musculo-Skeletal (locomotor)system: It enables the body to move using muscles. It supports the body and itsorgans. 10 B. Body Membranes Body membranes are composed of thin layers of tissue that cover, separate, and support visceral organsand line body cavities. They are 1- The Pleurae:covers thelungs. 2- The Pericardium:coverstheheart. 3- The Peritoneum: coversthe abdominalviscera. Fig: Body cavities 16  LOCOMOTOR SYSTEM The Locomotor system consists of bones, joints and muscles. A- TheBone The bone is a type of connective tissue formed of cells, fibers & matrix. Bone is hard due to calcification of its extracellular matrix, also it has a degree of elasticity due to presence of organic fibers. Functions of bones 1. Form the supporting framework of thebody. 2. Gives attachment to muscles and acts aslevers 3. Protection of underlying structures e.g. the skill protects the brain. 4. Storage of calcium &phosphorus. 5. Formation of blood cells by bonemarrow. Classification of bones (A) According to thestructure 1 -Compact bone: The bone appears as a solid mass. 2-Cancellous bone: The bone consists of a branching network oftrabeculae. (B) According to theshape 1- Long bones: as femur &humerus. 17 (C) Regionalclassification The human skeleton consists of two main parts a- Axial skeleton: which consistsof 1- Skull 2- Vertebralcolumn 3- Thoraciccage 4- Pelviccavity b- Appendicular skeleton: Which consists of 1- Bones of the upper limb. 2- Bones of the lower limb. Structure of long bones Each long bone has three parts, shaft and 2 ends: The shaft ▪ Is tubular in shape having a cavity called marrow cavity containing bonemarrow. The ends ▪ Is covered by articular cartilage. Epiphyseal plate: is a flat plate of hyaline cartilage liesbetween the ends and the shaft and is responsible for growth of the bone in length. 19 Fig: The human skeleton 20  ▪ The vertebral column is formed of33 vertebrae separated byfibrocartilagenous discs called intervertebraldiscs. The vertebrae are classified into the following groups: A. In the neck: 7cervical vertebrae. B. In the chest: 12 thoracicvertebrae. C. In the abdomen: 5lumbarvertebrae. D. In the pelvis: 5 sacral vertebrae. (Fused to form sacrum) and 4 coccygeal vertebrae (fused to formcoccyx) The structure of the typical vertebra It consists of a body (anteriorly) and a vertebral arch(posteriorly). These two parts enclose a space called the vertebral canal through which run the spinal cord. The vertebral body: is the anteriorpart. It articulates with bodies above and below by intervertebraldiscs. The vertebral arch: consists of 2 pedicles and 2laminae. Processes. 2- transverse processes (directed laterally). 3-One spine (directed posteriorly) 4- articular processes (directed vertically; 2 superior&2 inferior). 22  Fig: Structure of typical vertebra 3- Thoraciccage: It is formed of sternum, ribs and 12 thoracic vertebrae Sternum ▪ It is a flat hone in the anterior aspect of thethorax. ▪ It articulates with the upper 7ribs. Ribs ▪ There are 12 pairs ofribs. ▪ Each rib is attached posteriorly to the vertebral column and is continued anteriorly with a costalcartilage. ▪ Ribs can be classifiedinto A- Trueribs The upper 7 ribs, attached anteriorly to thesternum. 23  B- Falseribs: the8th , 9th , &10th areattached to each otherbytheir costalcartilages. the 11th& 12th ribs are free &are called the floating ribs. 4- Bonypelvis: Is composed of 2 hip bones and sacrum. Male pelvis is narrower than female pelvis. 24  Appendicular skeleton It is formed of the bones of the upper & lower limbs. Bones of theupperlimb Bones of the lowerlimb Region Bone Region Bone Shoulder Scapula & Pelvic girdle Hip bone girdle Clavicle Arm Humerus Thigh Femur Forearm Ulna (medially) Leg Tibia (medially) Radius (laterally) Fibula (laterally) Hand Carpal bones (8) Foot Tarsal bones (7) Metacarpal bones Metatarsal bones (5) (5) Phalanges(14) Phalanges(14) 25  B- Joints Definition: Joint is the meeting of two or more bones. Classification Joints are classified according to the tissues that lie between the bones into 1. Fibrousjoints: The articular surfaces of bones are joined by fibrous tissues. 2. Cartilaginousjoints: The articular surfaces of bones are joined together by cartilage. 3. SynovialJoints: The articular surfaces of bones are separated by a fluid -filled cavity. 1- Fibrousjoints Contain fibrous tissue between the articulating bones. Movement: No movement Examples: Sutures of the skull and joints between teeth and mandible Fig: Fibrous joint 26 2- Cartilaginousjoints ContainsCartilage (hyaline or fibrocartilage) between the two articulatingbones. Movement: limitedor No movement. Types: a- Primarycartilaginous ▪ The bones are connected by hyaline cartilage which becomes ossified byage. ▪ No movement ispossible. ▪ Example: Theepiphyseal plate in the longbones. (2) Secondarycartilaginous ▪ The bones are connected by fibrocartilage which is not ossified by age. ▪ A small amount of movement ispossible. ▪ Example: Joints between the vertebral bodies and Symphysis pubis. 27  Anatomy ▪ Example:hip joint & shoulderjoint. 30  Anatomy C- Muscles Types There are three types of muscles 1. Skeletalmuscles 2. Smoothmuscles 3. Cardiacmuscles Skeletal muscles ▪ They are the muscles that are attached to and produce movement of theskeleton. ▪ They are called voluntary muscles because they act by the will of man. ▪ They are called striated because they appear striated under the microscope. Characters 1- A skeletal muscle has two or moreattachments. ▪ Theorigin: The attachment of the muscle that moves theleast. ▪ The insertion: The attachment of the muscle that moves the most. 2-Theendsofamuscleareattachedtobonesbyfibroustissuecalled tendon. 4-The fleshy part of the muscleis called thebelly. 5- They are supplied by motor nerves. 31  Anatomy Comparison of the different types of muscles Skeletalmuscle Cardiacmuscle Smooth muscle Site Attached Heart Wall of viscera Toskeleton &blood vessels Action Voluntary Involuntary Involuntary Shape of cells Cylindrical Cylindrical Spindle shaped Striation Striated Striated Non- striated Branching No Branch &join No 32  Anatomy CARDIOVASCULAR SYSTEM The cardiovascular system transports blood to and from capillary beds in the tissues for the exchange of respiratorygases, nutrients and metabolites. The cardiovascular system consists of the heart & blood vessels. 1- Heart The heart is a conical hollow muscular organ which is enclosed by the pericardium in the thoraciccavity. The heart wall is formed mainly by muscle layer called myocardium and lined from inside by endothelial layer called endocardium. It is formed of 4 chambers 2 atria (right and left) and 2 ventricles (right andleft). Position: ▪ It lies obliquely behind the body of the sternum and the adjoining parts of the costal cartilages and is surrounded on each side by the lung andpleura. Shape & external features: ▪ The heart is pyramidal (or conical) in shape. It has a- Anapex b- Abase c- Four surfaces 1-Anterior(sternscostal) 2- Inferior(diaphragmatic) 33  Anatomy 3- Rightsurface 4- Leftsurface a)Apex of theheart: ▪ Directed downwards, forwards and to theleft. ▪ Formed by the leftventricle. ▪ Lies in the left5thintercostal space, 3.5 inchesfromthe midlineplane. b)Base ofheart: ▪ Forms the posterior surface of theheart ▪ Formed mainly by the left atrium and a small part by the right atrium. c)Surfaces of theheart: 1 - Anterior (sternocostal) surface: ▪ Directedanteriorly. ▪ Formed by the 2 atria and 2 ventricles 2- Inferior (diaphragmatic)surface: ▪ It rests on thediaphragm. o Its right 1/3 is formed by therightventricle o Its left 2/3 is formed by the leftventricle 3- Left surface: ▪ Formed mainly by the left ventricle and small part by the left atrium. 4 – Right surface: ▪ Formed by the rightatrium 34  Anatomy Difference between atria and ventricles Atrium Ventricle Wall thin thick Site occupy upper part occupy lower part Function receive blood from veins push blood into arteries Vessels right atrium: superior vena Right-ventricle: connected cava and inferior vena cava pulmonary trunk left atrium: 4 pulmonary to them left ventricle: aorta veins Valves of the heart The heart is provided by four valves to allow blood flow in one direction. 1- Atrioventricularvalves They are located between atria and ventricles. The tricuspid valve: lies between right atrium and right ventricle. 35  Anatomy The mitral valve: lies between left atrium and left ventricle. 2- Semilunar valves They are located between ventricles and the vessels connected to them. Pulmonary valve: lies between right ventricle and pulmonary trunk. Aortic valve: lies between left ventricle and aorta. Fig: Internal features of the heart Blood supply of the heart ▪ The heart is supplied by two coronary arteries (Rt. One & Lt. One) ▪ Coronaries originate from the ascending aorta. Nerve supply of theheart It is supplied by sympathetic & parasympathetic autonomic nerves. 36  Anatomy Conducting system of the heart The conducting system of the heart consists of cardiac muscle cells and conducting fibers that are specialized for initiating impulses and conducting them rapidly through the heart. It includes 1- Sino-atrial (SA) node:it initiates the heart beat (pace maker), lies at rightatrium. Fig: Conducting system of the heart 37  Anatomy Clinical notes: Swelling of the lymph nodes is a sign of immune system functioning to fight off the invaders of the body as bacteria and viruses. Lymphatic vessels provide a pathway for the spread of certain types of malignant tumors from their site of origin. Fig: Components of the Lymphatic system 48  Anatomy THE DIGESTIVE SYSTEM It is consisted of the alimentary canal and the accessory organs of digestion: Fig: The digestive system A) Alimentarycanal: This is a long tube trough which foodpasses. It starts at the mouth and ends at theanus. It consists of the followingparts: 1-Mouth 2-Pharynx 3-Oesophagus 4-Stomach, 5-Smallintestine 6-Largeintestine. 49  Anatomy B) Accessory organs ofdigestion: They are glands outside the alimentary tract and their secretion pass through ducts to enter the tract. 1- Salivaryglands 2- Pancreas 3- Liver and the biliarytracts The main functions of digestive system: 1- Ingestion: taking food into the alimentarytract 2- Digestion: mechanical and chemical breakdown offood 3-Absorption: passage of digested food from the alimentary canal to blood and lymphcapillaries 4- Elimination: excretion of undigested food asfaeces. - It is concerned with gridding, swallowing, digestion and absorption of the digestedfood. A-THE ALIMENTARY CANAL 1- MOUTH CAVITY The mouth (oral cavity) is divided into two parts: 1- The vestibule of the mouth: is the narrow space between lips and cheek "externally" and the teeth and gums"internally" 2- Mouth cavity proper: is the part enclosed by theteeth. 50  Anatomy The Palate Definition: It is the partition between oral and nasal cavities. Parts: = Hard palate: {bony part}. -Anterior 2/3 -formed of bone. = Soft palate: {muscular part} - Posterior 1 /3 of the palate. - Movable fibro muscular fold. - Its posterior border is free and shows the uvula hanging down from its middle. The Tongue It is a voluntary muscular structure at the floor of the mouth. Site: 1- Partly in the mouth {oral.part} 2- Partly in the pharynx {pharyngealpart}. External feature: The tongue has: 1- Apex: the anterior freeend. 2- Base: the posterior part; attached to the mandible and hyoidbone. 3- body: it has upper surface and inferiorsurface. Blood supply: Lingual artery (mainly) Nerve supply: = Motor: by hypoglossal nerve (12th cranial nerve) 51  Anatomy = Sensory: a) Anterior 2/3 o General sensation "pain, temperature and touch" by lingual nerve. o Taste sensation by chorda tympani (7th nerve). b) Posterior 113: o General and taste sensations by glossopharyngeal nerve (9th nerve). Function: = Mastication = Swallowing = Speech = Taste Fig: the tongue (superior view) The Teeth Each individual has two sets of teeth a- Temporary ordeciduousteeth b- Permanent teeth Temporary teeth Number: 20, {10 in eachjaw} They begin to erupt at 6 months and complete at 24month 52  Anatomy They include: 4 incisors, 2 canines, 4 molars in each jaw. Permanent teeth Number: 32 {16 in eachjaw} They start to erupt at 6 years and complete at 21years. They include: 4 incisors, 2 canines, 4 premolars, 6 molars in eachjaw. Fig: Permanent teeth Structure of a tooth It consists of: 1- The crown: the part above thegums. 2- The root: the part embedded in thebone. 3- Theneck:the Eachtooth has the following: 1- Pulp cavity: in the center; containing blood vessels andnerves. 53  Anatomy 2- Dentine: hard substance surrounding the pulpcavity. 3- Enamel: hard substance outside the dentine in thecrown 4- Cement: a substance fixes the root to thebone. Fig: Structure of the tooth Nerve supply: Upper teeth: by maxillary nerve. Lower teeth: by mandibular nerve. Blood supply: Arterial supply by maxillary artery. Venous drainage by internal jugular vein. 54  Anatomy 2- PHARYNX behind the nose, mouth and larynx. Extent: vertebra where it becomes continuous with the esophagus. The wall of the pharynx: It is composed of the following layers: 1- Inner layer of lining mucous membrane 2- Middle layer of the fibrous tissue. 3- Outer layer consisting of a number of voluntary muscle. Parts of the pharynx 1- Nasopharynx: ---- behind the nasal cavity. 2- Oropharynx: ---- behind the oral cavity. 3- Laryngopharynx: behind thelarynx. N.B.- Only the oral "oropharynx" and the laryngeal "laryngopharynx" parts of the pharynx are associated with the alimentary canal. 3-ESOPHAGUS Definition: It is a narrow muscular tube forming the food passage between pharynx& stomach. Dimensions Diameter: 2 cm. Course and Relation: It begins in theneck. 55  Anatomy It passes in the median plane in thethorax. It pierces the diaphragm and becomes continuous with the stomach. 4- STOMACH Site: lies obliquely in the upper and left part of the abdomen. Shape: variable; may be J-shape. External features: it has the following two orifices: cardiac and pyloric two curvatures: lesser and greater It is the most dilated part of the alimentary tract which connects the lower end of the esophagus to the duodenum. Surfaces A- Anterior surface: is related to = Left lobe of liver and anterior abdominal wall B - Posterior surface: is related to pancreas and left kidney 56  Anatomy Parts of stomach Fundus:is Body:is the main part below the fundus Pyloric portion: is the lower narrow part, the pyloric sphincter is at its lowerend. 5- SMALLINTESTINE Extent: from the pylorus to the ileocaecal. Length: about 6 meters long. Parts (a) Duodenum = The shortest & widest part of small intestine. = Form a C-shaped curve around the head of pancreas. = Length: 10 inches =25 cm. (b) Jejunum = The middle part of small intestine, Its length: about 2 meters. (c) Ileum = The terminal part of small intestine, Its length: about 3 meters. = Ends at the ileocaecal opening. 6- LARGEINTESTINE Extent: from ileocaecal junction to the anus. Length: about 1.5 meters. Parts : it is divided into Caecum Appendix 57  Anatomy Ascendingcolon Transversecolon Descendingcolon Sigmoidcolon Rectum Analcanal. B- ACCESSORY ORGANS OF DIGESTIVE SYSTEM 1) SALIVARYGLANDS They are 3 pairs, which pour their secretion into the mouth. They include: 2 parotid glands, 2 submandibular glands, 2 sublingual glands. a) ParotidGlands They lie on each side of the face just below the external auditory meatus. b) SubmandibularGlands They lie on each side of the face under the angle of the jaw. c) Sublingualglands They lie under the mucous membrane of the mouth. 58  Anatomy 2) PANCREAS It consists of: head, body & a tail. A- The head: lies in the concavity of the duodenum. B- The body: lies behind the stomach. C- The tail lies in front of left kidney and just reaches the spleen. Fig: Anatomy of pancreas 3) LIVER It is the largest gland of the body. Weight: about 1.5 k gm. Site: upper part of abdominal cavity mainly on the right side. Shape: wedge-shape. Lobes of liver: it has two lobes A- Largerightlobe. B- Small leftlobe. C- The right lobe has two smalllobes 1- Caudate lobe: on the posteriorsurface. 59  Anatomy 2- Quadrate lobe: on the inferiorsurface. The portal fissure "the hilum": It is the part where structures enter and leave the liver. Fig: Anatomy of the liver 60  Anatomy THE RESPIRATORY SYSTEM The respiratory system consists of Nose Pharynx Larynx BronchiandBronchioles Twolungs 1- The Nose Is formed of 2 parts: 1- External nose: covered byskin. 2- Internal part (nasalcavity): - Is divided into two equal parts by aseptum. - Connected to the pharynx through the posterior nasalopenings - Is lined by mucous membrane rich in bloodvessels. - Has olfactory receptors in its upperpart. 61  Anatomy - Receives the opening of paranasalsinuses. Function 1. Warm, humedify and purify the inspiredair. 2. Organ ofsmell. 3. Respiratory airpassage Clinical notes: Epistaxis: or bleeding from the nose. The most common cause is nose picking. Deviated septum: Deflection of the nasal septum is common. It is believed to occur most commonly in males because of trauma in childhood. 2- The Pharynx It is a muscular tube extending from the base of skull to the level of the 6th cervicalvertebra. Acts as passage for air andfood. Is divided into 3parts 1- Thenasopharynx Lies behind thenose. Receive the opening of the auditorytubes. Contains the pharyngeal tonsil "Adenoids'". 62  Anatomy 2- Theoropharynx Lies behind themouth. Contains the palatine tonsils. 3- Thelaryngopharnyx Lies behind the larynx. Clinical notes: Tongue and Airway Obstruction: In an unconscious patient, there is a tendency for the tongue to fall backward and obstruct the laryngeal opening. Tonsillitis: The palatine tonsils are a common site of infection, producing the characteristic sore throat and pyrexia. Adenoids: are enlarged nasopharyngeal tonsils usually associated with infection. 63  Anatomy 3- The Larynx It extends from the root of tongue to thetrachea. The junction between the larynx and the pharynx is guarded by the epiglottis which prevents entry of the food or fluid into the respiratory system duringswallowing. It is formed of a group of cartilages; the most prominent one isthe thyroid cartilage or Adams apple. It contains the vocal folds, so it has a role inphonation. Fig: Components of the Larynx 64  Anatomy 4- The Trachea (The WindPipe) It starts from the larynx to the primarybronchi. It is 10 cm inlength. Its wall contains 15-20 incomplete C shaped cartilaginous rings that are deficient posteriorly to help the act ofswallowing. It ends by dividing into right & leftbronchus. 65  Anatomy 6- TheLungs There are two lungs, covered by the pleural, separated by mediastinum. The lung is covered by the pleura. Shape: Each lung is Cone-Shaped, and has An apex: the upperend A base: directed downward and resting on thediaphragm Twosurfaces: Lateral surface: convex and related to the ribs Medial surface: concavo-convex and related to the heart. It contains the hilum which is the area through which structures enter and leave the lung. Fissures and lobes of the lung The right lung: is divided into three lobes (superior, middle and inferior) by two fissures oblique and horizontalfissures. The left lung: is divided into two lobes (superior and inferior) by the obliquefissure. Each lobe is divided intosegments. The alveoli are where gaseous exchange occurs between the air and theblood. 67  Anatomy 3-Autonomic nervoussystem Part of nervous system concerned with innervation of involuntary structures as heart, smooth muscles & glands. It is distributed through central & peripheral nervous system. It is divided into 2 parts: Sympathetic system: Prepare the body for an emergency. It increases the heart rate, raises the blood pressure, inhibits peristalsis and closes the sphincters Parasympathetic system: Responsible for conserving and restoring energy. It decreases the heart rate, increases the peristalsis & glandular activity and open sphincters. 76  Anatomy ENDOCRINE GLANDS These are ductless glands that secrete hormones directly into the blood. 1- Pituitary gland It is a small endocrinegland. It lies in a special fossa in the cranial cavity and connected with the base of thebrain. It has two lobes; anterior and posteriorlobes. Anterior lobe of the pituitary gland secretes growth hormone, prolactin and different hormones which control the secretions of other endocrineglands. Posterior lobe of the pituitary gland secretes antidiuretic hormone andoxytocin. 77  Anatomy 2-Thyroid gland It lies in the lower part of the front of the neck clasping the larynx and upper part of thetrachea. It has two lobes joined across the median plane by an isthmus. It secretes thyroxinehormone. Its enlargement calledgoitre. 3-Parathyroid glands They are four in number, two in each side behind the thyroid gland. They secrete parathrmone hormone which controls the level of Calcium and phosphorus inblood. 78  Anatomy CONTENTS Chapter Page N. 1 Anatomical terminology 3 2 Integumentary system 12 3 Locomotor system 17 4 Cardiovascular system 33 5 Lymphatic system 46 6 Digestive system 49 7 Respiratory system 61 8 Urinary system 69 9 Reproductive system 72 10 Nervous system 73 11 Endocrine system 77 12 Model Exams 80 13 References 88 89