Physiology - First Year Nursing PDF

Digestive system Definition of digestion: It is the breakdown of complex large macro-molecules into smaller simpler ones that can be easily absorbed. Definition of absorption It is the transfer of digested food particles into the blood stream to be used by different body tissues and o...

Digestive system Definition of digestion: It is the breakdown of complex large macro-molecules into smaller simpler ones that can be easily absorbed. Definition of absorption It is the transfer of digested food particles into the blood stream to be used by different body tissues and organs. Function structure of the digestive system 1- Digestive tract: extending from the mouth to the anus. 2- Glands: salivary glands, liver and pancreas. Digestive secretions: Salivary secretion, gastric secretion, bile secretion and pancreatic secretion. A) Mouth & Buccal cavity Digestion occurs in the mouth through 3 pairs of salivary secretions: 1- Parotid gland: 20% 2- Submandibular gland: 70% 3- Sublingual gland: 10% Functions of the saliva: 1- Digestion of food: starch will be digested through ptyalin enzyme. 2- Food lubrication. 3- Taste sensation. 4- Keeps the buccal cavity moist, so it helps in speech. 5- Keeps the mouth and teeth clean due to presence of antibacterial enzymes and antibodies. 6- Heat loss. 7- Acts as buffer keeping the oral pH7. 8- Excretory route: for excretion of harmful irritant substances e.g. lead. B) Stomach: It is divided into fundus, body, and pylorus. Gastric Juice: The stomach secretes 2.5 liters per day, highly acidic juice (pH 1-2) because it is rich in HCl, it its composed mainly of water, also it contains enzymes for digestion (pepsinogen, lipase) and mucous. Functions of the gastric juice: 1- HCl: activation of pepsinogen into pepsin which starts protein digestion, killing of ingested bacteria & helps absorption of iron and calcium. 2- Mucous: protects the gastric mucosa from the HCl. 3- Enzymes: pepsin responsible for protein digestion, lipase responsible for fat digestion. C) Biliary system: Bile is an important juice synthesized in the liver and secreted from the gall bladder; it is a golden yellow highly alkaline secretion (pH 7.8-8.6) because it contains high concentration of bicarbonate, it volume is 500 ml daily. Function of bile: 1- Fat digestion and absorption. 2- Its bicarbonate content neutralize the gastric HCl. 3- Excretory route for cholesterol, bacteria. Function of the gall bladder: 1- Storage of bile 2- Concentration of bile: through absorption of water. 3- Secretion of bile: contraction of the wall and relaxation of the sphincter. 4- Mucous secretion: protection of the gall bladder wall. Function of the liver: 1- Metabolic function: liver is considered as the glucostate organ (glucose regulating), in case of increase blood glucose level, it is stored as glycogen and vice versa. In addition, it is responsible for protein synthesis as well as fatty acid oxidation for energy supply. 2- Storage function: liver stores iron, vitamins, 450 ml blood. 3- Detoxification of drugs and toxins. 4- Inactivation of hormones. D) Pancreas: It is considered to be an endocrine gland that secretes insulin and exocrine gland that secretes pancreatic juice that is important in food digestion. Pancreatic juice: It is a highly alkaline juice due to its high bicarbonate content (pH 8), its volume daily equals 1.5 liters. It is composed of water and group of proteolytic, lipolytic enzymes. E) Small intestine: It is considered to be the best site for food absorption due to its long length, full of villi, richly supplied by bold vessels and lymphatic’s. F) Large intestine: Functions: 1- Absorption of water.  2- Excretion: e.g. heavy metals. 3- Storage of feces. 4- Defection. 5- Mucous secretion. Control of GIT activates (motility & secretion): The GIT is controlled by autonomic nervous system whether sympathetic nervous system that decrease all activates (relaxation of the wall and contraction of the sphincter, decrease GIT secretions) or parasympathetic nervous system that increase all activities (contraction of the wall and relaxation of the sphincter, increase GIT secretions). GIT is controlled by autonomic nervous system Sympathetic Para sympathetic All activities In all activities *Relaxation of the wall and *Contraction of the wall and Contraction of sphincters Relaxation of sphincters * Secretions * Secretions  Renal System - The renal system consists of 2 kidneys - Each kidney curtains 1 million of nephrons - Nephrons are functional & structural unit of the kidney Functions of the kidney    Excretion of Homeostasis Endocrinal   Keep internal 1) Secretion of erythropoietin Waste products as environment + RBCs production Excess normal 2) Activation of Vit. D strong Urea substances as constant bones ‫من حيث‬ Creatinine H2O 3) Secretion of renin regulate 1) blood pressure Glucose 2) H2O, electrolytes blood pressure 3) PH - Renal Failure: 1)  urea 2)  creatinine  3) Edema 4) Electrolytes disturbance as  K level hyperkalemia very dangerous effect on heart 5) Hypertension (HTN) 6) Anemia 7) Weak bones - How to diagnosis renal failure:- If > 75% of nephrons of kidney are lost Autonomic nervous system Anatomically, nervous system can be divided into: Central N.S. Peripheral N.S Brain Spinal cord 12 pairs of 31 pairs of spinal Cranial nerves nerves Physiologically, nervous system is divided to: Sensory Motor Somatic Autonomic Voluntary Involuntary Controls skeletal Control cardiac and muscle smooth muscles  Autonomic nervous system is divided to: Sympathetic Parasympathetic Emergency conditions: Resting and eating conditions As fright, fear, exercise, hemorrhage. as reading, eating micturition Generalized. Localized. Arise from spinal cord only Arise from brain and spinal cord General functions of sympathetic nervous system: On cardiovascular system: 1. Increase heart rate. 2. Increase heart contraction force. 3. Vasoconstriction of blood vessels. 4. Increase blood pressure. On respiratory system: 1. Bronchial dilatation. 2. Decrease secretions. On GIT 1. Decrease secretions and motility. Increase sweat secretion Stimulate glycogenolysis to increase blood glucose to give energy. General functions of parasympathetic nervous system: On cardiovascular system: I. Decrease heart rate. II. Decrease heart contraction force. III. Vasodilation of blood vessels. IV. Decrease in blood pressure. On respiratory system: I. Bronchial constriction II. Increase bronchial secretions. On GIT: I. Increase GIT motility and secretions. II. Contraction of the wall of gall bladder. Helps micturition and defecation. Helps in reading by enhancing near vision.  Respiratory System Definition of respiration:- It’s uptake of O2 and removal of Co2 released from the body. * Structure of the respiratory system:- 1. It consists of → Upper air ways, nose, pharynx, larynx Lower airways, tracheobronchial tree 2. It contains respiratory muscles Diaphragm External intercostal MS Internal intercostal MS   Major inspiratory muscles Expiratory muscles 3. Center of respiration present in brain stem * Mechanism of respiration:- Normally respiratory rate 12-16 times/mind respiration has 2 phases:- the process of inspiration (moves air into the lugs) is followed by expiration (moves air outside). Functions of respiration    Gases exclusion Secretory function Acid – base O2 & Co2 Surfactant balance ACE Angiotensin converting enzyme  Regulation of respiration (nervous) (Chemical) in the brain Through the level of Po2 & PCo2 & H+ conc. Important respiratory diseases 1- Hypoxia → It’s repetition of decrease  oxygen supply to the tissues 2- Cyanosis → bluish discoloration on of the skin & mucus membranes (lips, nail beds, ear lobes) It occurres when deoxygenated Hb  above 5 gm/100 ml blood. 3- Bronchial asthma:- It’s a chronic inflammatory disease of the airways characterized by airway obstruction. Cardiovascular system  1. Right Atrium 2. Right Ventricle Between 1&2 → Tricuspid valve 3. Pulmonary artery 4. Left atrium 5. Left ventricle Between 5&6 → Mitral valve 6. Aorta Pulmonary circulation: Right atrium → Right ventricle → lungs → Left atrium Systemic circulation: Left atrium → Left ventricle → Body→ Right atrium Intestine Liver * Left ventricle is stronger than right ventricle - The artery feeding the heart “coronary artery” - If blocked → Angina pectoris  Heart rate = 50-90 beat per minute Factors effecting heart rate: 1- Emotions → H.R 2- Exercise → H.R 3- Sleep →  H.R 4- Temperature →  Temp → H.R 5- Arterial blood pressure →  blood pressure →  H.R Definitions:- Number of heart beats per minute If increased  more than normal >90 If decreased  below normal