Handbook of Human General Anatomy for Nursing Students 2023-2024 PDF

Handbook of Human General Anatomy for nursing students SOHAG FACULTY OF MEDICINE 2023-2024  In this Anatomical Position  The body is assumed to be standing,  Head, eyes, and toes directed anteriorly (forward).  Upper limbs by the sides with t...

Handbook of Human General Anatomy for nursing students SOHAG FACULTY OF MEDICINE 2023-2024  In this Anatomical Position  The body is assumed to be standing,  Head, eyes, and toes directed anteriorly (forward).  Upper limbs by the sides with the palms facing anteriorly.  Lower limbs close together with the feet parallel and the toes directed anteriorly. ANATOMICAL TERMS  Anterior (frontal) ►Towards the front.  Posterior (Dorsal) ►Towards the back.  Superior ►Towards the head.  Inferior ►Towards the feet.  Proximal ►closer to the root. The elbow is proximal to the wrist on the upper extremity.  Distal ► away from the root. The elbow is distal to the shoulder joint on the upper extremity.  Median ►A point or area on the midsagittal plane (median plane).  Medial ►A point or area that is closer to the midsagittal plane than another.  Lateral ►A point or area that is more distant from the mid-sagittal or median plane. For example the outer side of the elbow is lateral when compared with, the inner side. 1  ……………………………………………………………………. Skin Skin is the outside covering of body tissue, accounts for 12%% of body weight. Skin performs the following functions: 1. Protection for the body from environmental effects. 2. Sensation: contains a variety of nerve endings that jump to heat and cold, touch, pressure, vibration, and tissue injury; 3. Heat regulation through sweat glands, blood vessels, and fat. 4. Storage : acts as a storage center for lipids and water 5. Absorption: Oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in small amounts, The skin consists of a superficial cellular layer, the epidermis, which creates a tough protective outer surface, and a basal (deep) layer, the dermis. 2 Fascia: A fascia is a connective tissue that surrounds muscles, blood vessels, and nerves, binding those structures together. It consists of a superficial fascia and a deep fascia Systemic anatomy: body system=a group of organs that work together to carry out a particular function. The skeletal system consists of bones and cartilage. The articular system consists of joints. The Muscular system The cardiovascular system. The respiratory system. The digestive system. The urinary system The reproductive system The nervous system. The endocrine system 3  The Skeletal System Includes two main parts  The axial skeleton consists of the bones of the head (skull), neck (cervical vertebrae), and trunk (ribs, sternum, vertebrae, and sacrum).  The appendicular skeleton consists of the bones of the limbs (upper and lower), including those forming the pectoral (shoulder) and pelvic girdles. Bone: A living tissue is a highly specialized hard form of connective tissue that makes up most of the skeleton. Functions of bones:  Protection for vital structures.  Support for the body.  The mechanical basis for movement.  Storage for salts (e.g., calcium).  A continuous supply of new blood cells (produced by the marrow within many bones). 4 Cartilage: semi rigid connective tissue where more flexibility is necessary. (e.g., the costal cartilages that attach the ribs to the sternum). The fibrous layer that surrounds bone is periosteum; The fibrous layer that surrounds cartilage is perichondrium. The periosteum and perichondrium help nourish the tissue Types of Bones in the Human Body There are 6 types of bones in the human body. 1. Long Bones (bones of limbs) The Long Bones are those that are longer than they are wide. The long bones include clavicle, Humerus, Radius, Ulna, metacarpals and phalanges bones of the upper limbs- Femur, Tibia, Fibula, metatarsals and phalanges bones of the lower limbs 2. Short Bones: Bones that is as wide as they are long. Examples of these bones include the carpal bones in the hand and tarsal bones in the foot. 3.Flat Bones: The classic example of a flat bone is the Scapula (shoulder blade). The Sternum (breast bone), Cranium (skull). 4. Irregular Bones: These are bones in the body which do not fall into any other category, due to their non-uniform shape. Good examples of these are the Vertebrae and Sacrum 5 5. Sesamoid Bones: usually short or irregular bones, imbedded in a tendon. The most obvious example of this is the Patella (knee cap) Sesamoid bones are usually present in a tendon where it passes over a joint to protect the tendon 6-Pneumatic bones: are bones which contain air filled cavities as bones enclosing Paranasal sinuses Adult Human Skeleton Is made up of 206 Bones and 32 teeth The axial skeleton 1. The skull consists of 22bones; cranial bone or brain base (8) and facial bones (14). 6 The skull encases and protects the brain and organs of special sense (organs of vision, hearing, balance, taste and smell) 2. The vertebral column: Consists of 33 vertebrae which are named according to their region and position. From top to bottom:  Cervical: 7 vertebrae (C1–C7)  Thoracic: 12 vertebrae (T1–T12)  Lumbar : 5 vertebrae (L1–L5) 7   Sacrum: 5 (fused) sacral vertebrae (S1–S5)  Coccyx: 4 (3–5) (fused) coccygeal vertebrae (Tailbone) Vertebrae are separated from each other by intervertebral discs. interverte bral disc 3. Thoracic cage: consists of thoracic vertebrae, 12 pairs of ribs, the sternum , and the costal cartilages (that attach the ribs to the sternum). The first seven pairs of ribs are called true ribs, Ribs 8–10 are known as false ribs, pairs 11 and 12 are floating ribs 8  Appendicular skeleton A. Bones of upper limb: The upper limb is composed of the shoulder girdle, arm, forearm and hand. Bones of the shoulder girdle: are the scapula and clavicle, together these 2 bones surround the upper part of the shoulder like a belt Clavicle As any long bone, the clavicle has a shaft and two ends Medial (sternal) end: articulates with the sternum to form the sternoclavicular joint. Lateral (acromial) end: articulates with the acromion of scapula to form the acromioclavicular joint. Scapula 9 It is a flat triangular in shape having three borders (superior, medial and lateral) two surfaces (anterior and posterior) and 2 processes (acromion and coracoid process). Glenoid cavity: It lies on the lateral angle to articulate with the head of the humerus to form the shoulder joint. The bone of the arm Humerus: As any long bone, the Humerus has a shaft and two ends. The upper (proximal) end contains the Head which is articular smooth surface that enters in the formation of the shoulder joint. Lower (distal) end: consists of the trochlea and capitulum, both of which share in the elbow joint. 11 Bones of the forearm: the radius (laterally) and the ulna (medially). Radius: As any long bone, the radius has a shaft and two ends. Upper end: contains the head which articulate with the capitulum in the elbow joint. Lower end: It is broader and articulate with the carpal bone in the wrist joint. Ulna As any long bone, the ulna has a shaft and two ends. Upper end: contains the trochlear notch which articulates with the trochlea in the elbow joint. Lower end: It is smaller than the upper end (don’t share in wrist joint) 11 Bones of the hand: consists of the 8 carpal bones, 5 metacarpal bones and 14 phalanges (2 for thumb and 3 for each finger).  Carpal bones: consists of 8 carpal bones arranged in 2 rows: proximal and distal.  Metacarpal bones: 5 metacarpal bones  Phalanges: Each digit has 3 phalanges: proximal phalanx, middle phalanx and distal phalanx. However, the thumb has only 2 phalanges. B. Bones of lower limb The lower limb is composed of the pelvic girdle, thigh, leg and foot. The bones of these segments are as follows: Bones of the pelvic girdle: Hip bone (irregular bone) The hip bone consists of three parts  Ilium: the upper part of the hip bone  Pubis: forms the anterior and lower part of the hip bone.  Ischium: forms the lower and posterior part of the hip bone. The acetabulum is a concave part of the lateral surface of the pelvis bone. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint. 12 Bone of the thigh: Femur: As any long bone, the femur has a shaft and two ends.  Upper end: contains the head which meets the acetabulum, forming the hip joint.  Lower End: It is expanded and consists of medial and lateral condyles (articulate with the 2condyles of tibia in the knee joint) anteriorly they articulate with the patella Bones of the leg: the fibula (laterally) and the tibia (medially). 13 Tibia: As any long bone, the tibia has a shaft and two ends.  Upper end: composed of 2 condyles (medial and lateral) articulate with the 2condyles of femur in the knee joint.  Lower end:It articulates with the tarsal bones below, to form the ankle joint. Fibula:As any long bone, the fibula has a shaft and two ends.  Upper end (called the head)  Lower end:It articulates with the tarsal bones below, to form the ankle joint Skeleton of the foot The bones of the foot are: 7tarsal bones, 5metatarsal bones and 14phalanges (3 in each toe except big toe has only 2). 14  Articular system (Joints) A joint is the point where two or more bones meet. Classified by structure and function into: Structural classification: Based on material binding bones together and whether or not a joint cavity is present three structural classifications:  Fibrous  Cartilagenous  Synovial Types of Joint 1-Fibrous joints (immoveable) The articulating bones of fibrous joints are united by fibrous tissue. Examples are joints between skull bones (sutures) and where the teeth are held to their bony sockets. 2-Cartilagenous (partially moveable) The articulating structures of cartilaginous joints are united by cartilage.  Primary cartilaginous joints; are united by hyaline (transparent) cartilage these joints permit growth of the length of the bone, examples are growing bones. 15   Secondary cartilaginous joints: bones united by fibrocartilage (mixture of white fibrous tissue and cartilaginous tissue), examples are the intervertebral discs between the vertebrae of the vertebral column. 3-The synovial Joint (freely moveable): The most common type of joints within the human body. Synovial joints contain the following structures: 16   Articular cartilage: hyaline cartilage covering articular surfaces  Synovial cavity small potential space inside capsule full of synovial fluid.  Joint capsule: all connective tissue that surrounds the joint  A synovial membrane which secretes synovial fluid, it covers the inner layer of the capsule and articular bones except these covered with articular cartilage. Types of synovial joints according to axes of movements:  Uniaxial joints: movements take place around one axis (e.g. elbow joint)  Biaxial allowing movement around 2 axes like (e.g. wrist joint).  Polyaxial allowing the full range of movement (e.g. shoulder and hip joints). The muscular system There are 3 different types of muscles Skeletal muscle  Skeletal muscles are attached to the skeleton  Skeletal muscles are voluntary muscles  Skeletal muscles named striated muscles as they are formed of fibers that are combined into parallel fibers.  They are supplied by somatic nerves. Cardiac muscle  As the name should tell you, cardiac muscle is found only in the heart.  Like smooth muscle, cardiac muscle is involuntary and like Skeletal muscle cardiac muscle is striated.  It is supplied by autonomic nerves Smooth muscle  Smooth muscle is found in our internal organs: in our digestive system, our blood vessels, our bladder, and our respiratory organs  Smooth muscles are involuntary muscles.  They are supplied by autonomic nerves. The skeletal muscles: They produce the movement of the skeleton. Attachment of the muscle: 17 The muscle has 2 attachments. Origin attachment to the immovable bones. Insertion which usually move with the contraction of the muscle. Muscles contraction causes the insertion to move toward the origin N.B: Diaphragm: Skeletal muscle separates the thoracic cavity containing the heart and lungs, from the abdominal cavity. Performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs. 18  Cardiovascular System (Circulatory system)  An organ system that permits blood to circulate and transport nutrients to and from the cells in the body  The main components of the cardiovascular system are the heart, and the blood vessels (arteries-veins). Heart  The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs.  The blood that is returned to the right atrium is deoxygenated (poor in oxygen) and passed into the right ventricle to be pumped through the pulmonary artery to the lungs for re-oxygenation and removal of carbon dioxide.  The left atrium receives newly oxygenated blood from the lungs which is passed into the strong left ventricle to be pumped through the aorta to the different organs of the body. Chambers of the heart Right atrium Non –oxygenated blood pass to the right atrium through three vessels. These are:  the superior and inferior venae cavae: returns blood from the body;  the coronary sinus: returns blood from the walls of the heart itself Blood passes into the right ventricle through the tricuspid valve Right ventricle  Receives non –oxygenated blood from Rt atrium ,  Then blood passes through the pulmonary artery to the two lungs where oxygenation of this blood occurs. Left atrium  Oxygenated blood pass from the lungs to the left atrium through the four pulmonary veins (two from each lung) from the left atrium,  Blood passes into the left ventricle through the mitral valve Left ventricle 19   Receives oxygenated blood from Lt atrium.  Oxygenated blood in the left ventricle pass through the aorta to the different parts of the body. Pericardium Is a double walled fibroserous sac that encloses the heart and the roots of its great vessels. It is formed of two layers -Outer fibrous layer called fibrous pericardium. -Inner double-layered sac formed of a transparent membrane called serous pericardium. 21 Blood supply of the heart: by two coronary arteries which arise from the ascending aorta Venous drainage of the heart: mainly by coronary sinus drain into right atrium Arteries and Veins 21 Arteries (singular artery)  Arteries are blood vessels which carry blood from the heart to the body.  All of which carry oxygenated blood with the exception of the pulmonary artery.  The most widely known artery within the human body is the Aorta. This is the largest of all blood vessels and transports blood away from the heart where it then branches into smaller arteries.  Smaller arteries divide further until they are classed as arterioles.  Arterioles continue to branch into smaller and smaller vessels which, once they have decreased in size below 10 micrometers in diameter are known as capillaries. Veins (singular vein)  Veins are blood vessels which carry deoxygenated blood from the body to the heart.  All of which carry deoxygenated blood except the pulmonary veins, which carry oxygenated blood, from the lungs, back to the heart.  At tissue level capillaries drain blood into venules, which are very small veins,  as venules return to the heart merge into larger veins which drained into either the Superior Vena Cava (it returning from tissues and organs above the heart) or the Inferior Vena Cava (it returning from tissues and organs below to the heart).  These two large veins merge and return blood to the right atrium of the heart.  Veins also contain valves which prevent the back flow of blood. What Are The Differences Between Arteries And Veins? 1) Arteries are the carriers of red oxygenated blood directly from the heart, whereas veins carry de-oxygenated blood towards the heart. 2) Blood is under great pressure in arteries; hence it flows fast. In veins the blood is not under great pressure, hence it flows more slowly and smoothly. 3) Arteries have no valves but veins have internal valves along their length to prevent back flow of blood. 4) Arteries have thick muscular walls while veins have relatively thin muscular walls. 22  Respiratory system Conducting parts for air passage: 1-Nose:  The nose is the upper part of the respiratory system and contains the organ of smell.It is divided into right and left nasal cavities by the nasal septum.  Function of the nose: -Respiration -Olfaction -Filtration of dust -Humidification of inspired air -Reception of secretions from the paranasal sinuses and nasolacrimal ducts. 2-Pharynx:  It is a muscular tube  Extends from the base of the skull to the level of sixth cervical vertebrae end where it is continuous with the oesophagus.  divided into three sections: nasopharynx, oropharynx and laryngopharynx 23 3-Larynx (Voice Box)   Your larynx is a hollow box (consists of cartilages connected by muscles and ligaments) in the middle of your neck, just above your trachea (windpipe) and in front of your esophagus. It makes it possible for you to make sounds by vocal cords, which is why it’s also called your voice box. It also lets air pass from your throat to your trachea and on to your lungs.  The larynx is open in respiration - closed during swallowing by epiglottis -As a partially closed during the production of voice.  Begin: at the level of third cervical vertebrae.  End: At the level of sixth cervical vertebrae. 24 4-Trachea (12 cm):  The trachea is a fibrocartilaginous tube formed by incomplete cartilaginous rings (which keep the trachea patent), are deficient posteriorly where the trachea is adjacent to the esophagus.  The trachea extends from the inferior end of the larynx at the level of the 6th cervical vertebra. It ends by dividing into right and left main bronchi Lungs Each lung has pyramidal shape with apex and base. Apex: Directed upwards and projects into the root of the neck. Base: Concave and directed downwards where it is related to the diaphragm. Each lung has 2 borders and 2 surfaces 25   Anterior border: Sharp and thin  Posterior border: Thick and rounded and lies by the side of the vertebral column.  Lateral (costal) surface: Convex and is related to the ribs and intercostal spaces.  Medial surface (mediastinal): Contains the hilum of the lung. Lobes of the Lung: Right lung: is divided into 3 lobes (upper, middle and lower) Left lung: is divided into 2 lobes only (upper and lower) Differences between right and left lungs: 1. The right lung has 3 lobes, but the left lung has only 2 lobes. 2. The right lung is short and broad (presence of the liver pushes the diaphragm upwards on the right side). 3. The left lung is long and narrow (the heart lies on the left side). 4. The left lung has a cardiac notch( impression) on its anterior border and a lingula just below the notch. PLEURA : It is a closed serous sac (one on each side) formed of 2 layers: 1. Parietal layer: lines the thoracic wall. 2. Pulmonary (visceral) layer: covers the lung and lines its Fissures. 26  Digestive system The digestive system include  The gastrointestinal tract (GIT) which starts at the mouth and ends at the anus.  Accessory digestive glands: the liver, gall bladder and pancreas. 1-The mouth (oral cavity): The mouth is the first portion of the GIT that receives food and saliva continues into the pharynx which ends at the oesophagus. 2- Pharynx: This is common for air and food. 3-The esophagus: Consists of a fibromuscular tube through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. it is about 25 cm long. 27 4-Stomach Position: The stomach occupies left hypochondriac region (left side below diaphragm). Shape: J-shaped stomach The stomach has 2 orifices (cardiac and pyloric), 2 surfaces (anterior and posterior) and 2 curvatures (greater and lesser) Curvatures of the stomach  Greater Curvature: to the left  Lesser Curvature: to the right Orifices of the stomach: 1) Cardiac orifice: It is the opening by which the oesophagus communicates with the stomach. 2) Pyloric orifice: It is the opening by which the stomach communicates with the duodenum(1st part of small intestine) Parts of the stomach: The stomach is divided into 3 parts: fundus, body and pyloric part. 1) Fundus: is the upper part of the greater curvature above the cardiac opening 28  2) Body: the large part between fundus above and the pyloric part below. 3) Pyloric part: is the lower part and below the lesser curvature. It is subdivided into the following parts: a- Pyloric antrum: is the dilated proximal part of the pyloric region b- Pyloric canal: is the narrow canal (2-3 cm long) distal to the antrum. It ends at the pyloric orifice which is surrounded by a thick muscular ring called the pyloric sphincter (pylorus). 5-Small intestine The small intestine (measures 6 meters) in length and has a smaller diameter than the large intestine. It is divided into 3 parts: duodenum (fixed part), jejunum and ileum (free part). 1) Duodenum: is the proximal 10 inches. 2) Jejunum: follows the duodenum and forms the proximal 2/5 of the Free part. 3) Ileum: is the distal 3/5 of free part of the small intestine and joins the caecum at the ileocaecal junction. Duodenum It is a C-shaped tube, 10 inches (25cm) long, and is curved around the head of the pancreas. 29 Jejunum and ileum The jejunum and ileum are in the form of coils or loops which are suspended from the posterior abdominal wall by a large fold called mesentery. This mesentery allows free movements of the loops Differences between jejunum and ileum: 1) Wall of the intestine: * The wall of the jejunum is thicker, than that of the ileum. * The mucosa of the jejunum shows circular folds which are thicker, larger and more numerous than those of the ileum. 2) The mesentery: The mesentery of the jejunum contains less fat The mesentery of the ileum, however, contains much fat. 3) Arterial arcades: These arterial arcades are few and simple in the region of the jejunum, but are more numerous and complicated in the region of the ileum. 6-Large intestine 31 The large intestine measures 1.5 meters and its diameter is greater than that of the small intestine It consists of the caecum, appendix, colon, rectum and anal canal. The large intestine differs from the small intestine by the presence of the following main features:  Taeniae coli: these are 3 longitudinal muscular bands in the wall of the colon  Sacculations (haustrations): these are sac-like dilatations in the wall of the large intestine especially in the colon.  Appendices epiploicae: these are small projections of fat scattered over the surface of the colon mainly. The caecum:  The most dilated part of the large intestine.  It forms the beginning of the large intestine and lies in the right side  The caecum is about 10 cm length.  It contains the vermiform appendix Vermiform appendix 31   The appendix length is from 2 to 20 cm (average 10 cm)  It opens by its base into the posteromedial aspect of the caecum about 2 cm below the ileocaecal opening.  The appendix lies mainly behind the caecum (retrocaecal). Colon: consists of 4 parts: ascending, transverse, descending and sigmoid. Ascending colon  It is 15 cm long, and begins at the ileocaecal junction as the upward continuation of the caecum.  It ascends in the right side of vertebral column.  It ends just below the liver by forming the right colic flexure. Transverse colon:  It is 50 cm long  Begins as the continuation of the right colic flexure.  Ends at the left colic felxure.  The transverse colon is suspended from the posterior abdominal wall by the transverse mesocolon Colic flexures Right colic flexure: It is formed by the terminal part of the ascending colon and the beginning of the transverse colon. Left colic flexure: It is formed by the termination of the transverse colon and beginning of the descending colon. Descending colon  It is 25 cm long.  It extends from the left colic flexure down to enter the pelvis. Sigmoid colon  It is 40 cm long.  It is S-shaped.  It begins at the left side of the inlet of the pelvis and ends at the middle piece of the sacrum where it is continuous with the rectum. Rectum  Begins: The rectum at the level of the 3rd sacral vertebra as the continuation of the sigmoid colon. 32   Ends: below and in front of the tip of the coccyx.  Length: Five inches long, and its lower part is dilated to form the rectal ampulla.  Continue below as the anal canal (4 cm) which ends as at the anus. What are the accessory glands of the digestive system and describe their functions? There are four accessory glands of the digestive system and they are the salivary glands, the pancreas, the liver and the gallbladder. Salivary Glands 33 The salivary glands are exocrine glands that produce saliva.The glands are found in and around your mouth and throat. All glands have ducts which open into the mouth cavity We call the major salivary glands the parotid, submandibular, and sublingual glands.  The parotid glands are a pair of major salivary glands wrapped around the mandibular ramus. It is one of a pair being the largest of the salivary glands  The submandibular glands located below the lower jaws.  The sublingual glands located inferior to the tongue Pancreas The pancreas is both an endocrine gland (producing insulin), as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. The pancreas lies in contact with the upper part of the posterior abdominal wall, extending transversely from the duodenum to the spleen. It is composed of 4 parts: head, neck, body and tail. 1) Head: occupies the concavity of the duodenum. 2) Neck: is the slightly constricted area between head and body. 3) Body: extends to the left crossing over the lumbar vertebrae. 4) Tail: is the narrow left end of the pancreas 34 Pancreatic ducts: The pancreas has 2 ducts (main and accessory): 1) Main pancreatic duct: The duct comes on the left side of the bile duct. The 2 ducts open into the 2nd part of the duodenum at its middle. 2) Accessory pancreatic duct: opens into the duodenum just above the main duct. Liver Is wedge-shaped and reddish brown in color because of its great vascularity. It lies mainly in the right hypochondrium (Rt side below diaphragm) The liver plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, detoxification and produces bile which aids in digestion Lobes of the liver The liver consists of a large right lobe and a smaller left lobe. * In addition to the right and left lobes there are 2 small lobes called quadrate and caudate lobes which are parts of the right lobe appear on the back of the liver. PORTA HEPATIS (hilum of liver): Contents: 35  1) Portal vein: posteriorly. 2) Hepatic artery: intermediate in position. 3) Right and left hepatic ducts: anteriorly. The portal vein is a vein that conducts blood from the gastrointestinal tract and spleen to the liver. This blood is rich in nutrients that have been extracted from food, and the liver processes these nutrients; the blood leaves the liver to the heart in the hepatic veins which open into the IVC. Biliary system 36 Hepatic ducts: The right and left hepatic ducts, one from each lobe of the liver join each other to form the common hepatic duct. Gall bladder The gall bladder is piriform in shape measuring 8-10 cm in length and 30-50 ml in capacity. It has a fundus, body and neck. It has function of bile storage Cystic duct: continuous with the neck of the gall bladder. It is 4 cm long, and passes downwards where it joins the common hepatic duct to form the common bile duct. Bile duct: (8cm) long, and is formed by the union of the cystic and common hepatic ducts. Spleen  It is soft, very vascular and very friable organ.  It lies in the left hypochondrium between the fundus of the stomach and the diaphragm. Function of spleen:  It mainly acts as a filter for purifying the blood.  Removing microbes and worn out or damaged red blood cells.  It is also an important organ in the immune system  Producing the white blood cells that fight infection and synthesize antibodies. 37  Urinary system Consists of the 2 kidneys, 2 ureters, the bladder, and the urethra. The functions of the urinary system is to eliminate wastes (excess water and excess electrolytes) as urine from the body and so regulate blood volume and blood pressure, and control levels of electrolytes and metabolites 1-Kidneys  Lie on the posterior abdominal wall, one on each side of the vertebral column. 38   Each kidney extends from level of 12th thoracic to level of the 3rd lumbar vertebrae.  Each kidney is about 4 inches long, 1 inches wide and 1 inch thick. It has 2 borders (medial and lateral), 2 surfaces (anterior and posterior) and 2 ends (upper and lower).  On the upper end of each kidney the adrenal gland rests  The hilum of the kidney lies on the medial border and contains the pelvis of the ureter (upper dilated part) and the renal vessels.  Each kidney consists of millions of functional units called nephrons 2-Ureters:  10 inches (25 cm) long, with its upper 1/2 situated in the abdomen and its lower 1/2 in the pelvis.  The ureter begins inside the kidney in the form of a dilated part called the renal pelvis and then extend downward.  The ureter passes ends in the wall of the bladder. 3-Urinary bladder  Lies in the pelvic cavity directly behind the pubic bones.  An empty bladder is pyramidal in shape with a mean capacity of (300 - 600mls)  The neck of the bladder: It is the lowest and most fixed part of the bladder, and is continuous with the internal urethral orifice 4-Male urethra  S-shaped  20 cm Length.  It extends from the internal urethral orifice at the neck of the urinary bladder to the external urethral orifice at the tip of the penis.  Division: It is divided into 3 parts: prostatic, membranous and spongy. (A) Prostatic urethra  passes downward and forward through the prostate gland  It measures 3 cm in length.  It is the widest and most dilatable part of the whole urethra. (B) Membranous urethra: It is 2 cm long. (C) Spongy (penile) urethra: 15 cm long. It extends from the end of the membranous urethra and ends at the external urethral orifice at the tip of the penis. 39 Sphincters of the urethra:  Internal urethral sphincter (involuntary), and surrounds the internal urethral orifice and neck of the bladder  External urethral sphincter (voluntary), and surrounds the membranous urethra 5-Female urethra  It is 4 cm long.  It begins at the internal urethral orifice and ends in front of the vagina by the external urethral orifice which lies directly in front of the vaginal orifice. ……………………………………………………………….. The female reproductive system (or female genital system)  Internal: The female internal reproductive organs are the vagina, uterus, uterine tubes (Fallopian tubes, oviducts) and ovaries.  External: external genitalia (skin folds) 41 1-Ovaries:  a pair of small glands about the size and shape of almonds,  Located on the left and right sides of the pelvic body cavity lateral to the superior portion of the uterus.  Ovaries produce female sex hormones such as estrogen and progesterone as well as ova ((singular ovum)). Each month during ovulation, a mature ovum is released. The ovum travels from the ovary to the fallopian tube, where it may be fertilized before reaching the uterus. 2-Fallopian Tubes:  A pair of muscular tubes that extend from the left and right superior corners of the uterus to the edge of the ovaries.  The fallopian tubes end in a funnel-shaped structure called the infundibulum, which is covered with small finger-like projections called fimbriae.  The fimbriae swipe over the outside of the ovaries to pick up released ova and carry them into the infundibulum for transport to the uterus.  The inside of each fallopian tube is covered in cilia that work with the smooth muscle of the tube to carry the ovum to the uterus. 41 3-Uterus (womb):  a hollow, muscular, pear-shaped organ  The lower part known as the cervix  Connected to the two fallopian tubes on its superior end and to the vagina (via the cervix) on its inferior end,  The inner lining of the uterus, known as the endometrium, provides support to the embryo during pregnancy and shredded outside as menstruation in the absence of pregnancy. 4-Vagina:  An elastic, muscular tube that connects the cervix of the uterus to the exterior of the body.  Its outer opening lies posterior to the urethra and closed in virgins by a thin membrane (hymen). ……………………………………………………………….. 42  Anatomy of the Male Reproductive System 1-Scrotum:  A sac-like organ made of skin and muscles that houses the testes.  The scrotum is made up of 2 side-by-side pouches with a testis located in each pouch. 2-Testes  The 2 testes are the male gonads responsible for the production of sperm and testosterone.  The testes are ellipsoid glandular organs around 1.5 to 2 inches long and an inch in diameter.  Each testis is found inside its own pouch on one side of the scrotum which is present outside the body. 3-Epididymis  The epididymis is a sperm storage area that wraps around the superior and posterior edge of the testes. 43   The epididymis is thin tubule that is tightly coiled into a small mass with head, body and tail.  Sperm produced in the testes moves into the epididymis to mature before being passed on through the other male reproductive organs. 4- The ductus deferens.  Known as the vas deferens  A muscular tube that carries sperm superiorly from the tail epididymis into the abdominal cavity to join the ejaculatory duct (from outside to inside the body). 5-Ejaculatory duct:  The union of the ductus deferens with the seminal vesicle (gland).  During ejaculation, the ejaculatory duct opens and expels sperms and the secretions from the seminal vesicles into the urethra.  The urethra in males is a common pathway for urine and semen (sperms + glands secretions). ………………………………………………………………………………………… Nervous system 44  Consists of highly specialized cells that transmit information rapidly between various parts of body.  Coordinates body voluntary and involuntary actions and transmits signals between different parts of its body  Divided into two parts: central nervous system (CNS) and peripheral nervous system (PNS).  The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord.  The peripheral nervous system (or PNS), is composed of nerves leading to and from the CNS. Central nervous system (brain- spinal cord) The brain: The brain lies within the skull and consists of four principal parts:  the brain stem  the cerebrum  the cerebellum  the diencephalon The brain weighs approximately 1.3 to 1.4 kg. 45 The brain stem: The brain stem consists of midbrain-pons and medulla oblongata, it connect the cerebrum to the spinal cord. The cerebrum: The cerebrum forms the bulk of the brain; it is divided into two hemispheres. Each hemisphere controls the activities of the side of the body opposite that hemisphere. The hemispheres are further divided into four lobes:  Frontal lobe  Temporal lobes  Parietal lobe  Occipital lobe The cerebellum: This is located behind and below the cerebrum and concerned mainly with equilibrium. The diencephalon  It includes the thalamus and hypothalamus.  The thalamus concerned with sensation.  The hypothalamus concerned mainly with emotion and endocrine function. 46 The spinal cord  Along tube like structure which extends from the brain.  The spinal cord is about 43 cm long in adult women and 45 cm long in adult men.  It lies within the vertebral column. The meninges: are three layers or membranes that cover the brain and the spinal cord. The outermost layer is the dura mater, the middle layer is the arachnoid mater, and the innermost layer is the pia mater. The meninges offer protection to the brain and the spinal cord by acting as a barrier against bacteria and other microorganisms. The Cerebrospinal Fluid (CSF) circulates around the brain and spinal cord (between arachnoid and pia matter). It protects and nourishes the brain and spinal cord. 47  The Peripheral nervous system The Peripheral nervous system is made up of two parts:  Somatic nervous system  Autonomic nervous system Somatic nervous system (cranial nerves –spinal nerves) 1. Cranial Nerves (from brain): There are 12 pairs of cranial nerves, known by number of by a name: the name usually reflects form, function or distribution of the nerve. Olfactory nerve (I), for smell. Optic nerve (II) for vision. Oculomotor nerve (III) innervates certain muscles of eye. Trochlear nerve innervates certain muscles of eye. Trigeminal nerve (IV) divides into 3 branches; ophthalmic, maxillary and mandibular and is sensory to face and scalp. Abducent nerve (VI), innervates certain muscles of eye. Facial nerve (VII), innervates muscles of the face. Vestibulocochlear (VIII) has 2 components: vestibular & cochlear. (Cochlear part responsible for hearing- Vestibular, responsible for sense of balance). Glossopharyngeal nerve (IX), sensory to the pharynx and tongue. Vagus nerve (X) has a diverse distribution including muscles of pharynx and larynx, viscera of chest and much of abdominal viscera. 48  Accessory nerve (XI) has two components: a cranial and a spinal part (innervate muscles of neck). Hypoglossal nerve (XII) supplies the muscles of the tongue. 2. Spinal Nerves (from spinal cord):  31 pairs of spinal nerves.  There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. Autonomic Nervous System This nervous system controls the nerves of the inner organs of the body on which humans have no conscious control. This includes the heartbeat, digestion, breathing (except conscious breathing) etc. Divided into 2 parts: sympathetic and parasympathetic. The parasympathetic division: "rest and digest", promotes the nerves return to regular function, and enhances digestion. The sympathetic division: "fight or flight", corresponds with arousal and energy generation, and inhibits digestion. ………………………………………………………………………………………… Endocrine System The endocrine system is made up of glands that produce and secrete hormones (chemical substances produced in the body that regulate the activity of cells or organs). The major glands of the endocrine system are the hypothalamus, pituitary, thyroid, parathyroids, adrenals and the reproductive organs (ovaries and testes). The pancreas is also a part of this system; it has a role in hormone production as well as in digestion. The hypothalamus: is located in the lower central part of the brain. It secretes hormones that stimulate or suppress the release of hormones in the pituitary gland. The pituitary gland is located at the base of the brain beneath the hypothalamus. It is often considered the most important part of the endocrine system because it produces hormones that control many functions of other endocrine glands. The pituitary gland is divided into two parts: the anterior lobe and the posterior lobe. 49 The thyroid gland is located in the lower front part of the neck. It produces thyroid hormones that regulate the body's metabolism. The parathyroid glands :are two pairs of small glands embedded in the surface of the thyroid gland, one pair on each side. They release parathyroid hormone, which plays a role in regulating calcium levels in the blood and bone. The two adrenal glands: located on top of each kidney. The adrenal glands are made up of two parts.  The outer part is called the adrenal cortex produces hormones called corticosteroids, which regulate the body's metabolism,  The inner part is called the adrenal medulla produces hormones called catecholamines help the body cope with physical and emotional stress. The pancreas: has a digestive and hormonal function. One part of the pancreas, the exocrine pancreas, secretes digestive enzymes. The other part of the pancreas, the endocrine pancreas, secretes insulin and Glucagon which regulates the level of glucose (sugar) in the blood. 51