Presentation Unit 3



(2) SYSTEMS INVOLVED IN NUTRITION Do you remember? Activity 1. Explain what each one of the arrows represents.. To start again, CLICK.

(3) 1 THE DIGESTIVE SYSTEM http:// watch?v=_l8aLmomDPU. https:// watch?v=s1q2srfUU0g.

(4) Introduction The digestive system is used for breaking down food into nutrients which then pass into the circulatory system and are taken to where they are needed in the body..

(5) Gastric glands:Secrete gastric juice and protective mucus Intestinal glands: •Secrete intestinal juice and protective mucus.

(6) 2 DIGESTION PROCESS. • watch?v=s1q2srfUU0g.

(7) Introduction Digestion can be considered as a series of steps: 1. Physical or mechanical digestion 2.Chemical digestion 3. Absorption 4. Egestion..

(8) 2.1 MECHANICAL DIGESTION Chewing In this step teeth are used to break down food into small pieces by cutting, tearing, crushing and grinding it. The tongue mixes saliva with the food and forms a bolus of food. That is a conscious act using voluntary muscles..

(9) 2.1 MECHANICAL DIGESTION • The rest of the process is automatic. • Thanks to the peristaltic activity, the bolus of food passes down the pharynx, through the oesophagus, not down the trachea!, and into the stomach..

(10) 2.1 MECHANICAL DIGESTION • The bolus passes down the esophagus by peristalsis. • Peristalsis is a wave of muscular contractions that push the bolus down towards the stomach..

(11) 2.2 CHEMICAL DIGESTION • Saliva, elaborated by the parotid glands, the submandibular glands, and the sublingual glands, contains amylase and maltase which break down the carbohydrates, especially starch..

(12) 2.2 CHEMICAL DIGESTION • To enter the stomach, the bolus must pass through the lower esophageal sphincter (cardia), a muscle that keeps stomach acid out of the esophagus..

(13) 2.2 CHEMICAL DIGESTION. • The stomach Cells which lined the inner wall of the stomach produce gastric juices. These juices contain proteases (enzymes)which break down proteins, and hydrochloric acid (HCl)..

(14) 2.2 CHEMICAL DIGESTION • The acid kills off any invading bacteria or viruses. • The enzymes help break down proteins. Chemical Digestion. • The mucus protects the lining of the stomach from being eaten away by the acid..

(15) 2.2 CHEMICAL DIGESTION • The digested bolus is now called chyme and it leaves the stomach by passing through the pyloric sphincter..

(16) 2.2 CHEMICAL DIGESTION • Thanks to the intestinal juices, the bile, produced by the liver, and the pancreatic juices, the digestion of food is completed. • The bile helps to digest the fats by emulsifying it into minute droplets. • The intestinal and pancreatic juices finish the chemical digestion (proteins, fats and carbohydrates) . • A whitish liquid paste is formed, called chyle, which contains water, nutrientsas the result of the digestion, and other non digested remains..


(18) 2.3 ABSORTINON OF NUTRIENTS •. The result of the digestion is to obtain nutrients, which are small enough to go through the walls of the digestive tract and pass into the blood. This process is called absorption.. •. It is in the small intestine where a major part of absorption occurs..

(19) 2.3 ABSORTINON OF NUTRIENTS The walls of the intestine contain veins and capillaries which absorb the nutrients into the bloodstream and then into all the cells of the body..

(20) 2.3 ABSORTINON OF NUTRIENTS. •Most of substances are absorbed in the jejunum (mainly) and ileum.. •In these parts, the inner wall of the small intestine is much folded making up the intestinal villi. •In the inner part of the intestinal villi there are capillary vessels (small blood vessels) and lymphatic vessels which take away the nutrients. •Then they are delivered to all the cells of the body..

(21) 2.3 ABSORTINON OF NUTRIENTS • Each villi itself has tiny fingerlike projections called microvilli, which further increase the surface area for absorption..

(22) 2.3 ABSORTINON OF NUTRIENTS The capillary vessels take away simple sugars and amino acids, and carry them to the liver via the portal vein. The lymphatic vessels transport the fatty acids and glycerol around the body and finally release them into the bloodstream..

(23) 2.3 ABSORTINON OF NUTRIENTS • The large intestine is used to absorb water from the waste material leftover and to produce vitamin K and some B vitamins using the helpful bacteria that live here..

(24) 2.4 EGESTION AND DEFECATION • All leftover waste is compacted and stored at the end of the large intestine called the rectum. • When full, the anal sphincter loosens and the waste, called feces, passes out of the body through the anus..

(25) 3. The respiratory system We breathe using the respiratory system We obtain oxygen from the air We expel the CO2.

(26) 3.1Anatomy of the respiratory system.

(27) 3.2 How does the respiratory system work Breathing has three phases:. Inhalation. Gas exchange. Exhalation.

(28) 3.2 How does the respiratory system work: Inhalation and exhalation.

(29) 3.2 How does the respiratory system work: Inhalation and exhalation During Inhaling, the brain sends electric impulses by nerves to the diaphragm and the inter costal muscles. The diaphragm contracts becoming flatter. The inter costal muscles also contract. These actions expand the thoracic cavity and increase the volume, with the volume increasing the internal pressure decreases which makes air enter the lungs through the mouth, nose and trachea. During Exhaling, the diaphragm and the inter costal muscles relax again, contracting the thoracic cavity thus squeezing the air out of the lungs to the trachea and mouth and nose to the atmosphere.

(30) Composition of inhaled air and exhaled air.

(31) 3.2 How does the respiratory system work: gas exchange

(32) 3.2 How does the respiratory system work: gas exchange.

(33) 4. The circulatory system The circulatory system transport nutrients, oxygen, CO2 and waste around the body. It is made up of blood, blood vessels and the heart.

(34) 4.1 Blood Vessels –Arteriesmove the blood away from the heart to the cells. Elastic Fibers Thick outer wall –Capillaries – where gas exchange takes place.. Very thin outer wall Connect all the cell in our body –Veinsmoves the blood towards the heart. Skeletal Muscles contract to force blood back from legs Thin outer wall One way valves.


(36) 4.2 The blood

(37) 4.2 The blood A. Plasma •. Liquid portion of the blood. Contains different substances such us nutrients and waste.

(38) 4.2 The Blood Blood cells a) Erythrocytes - Red Blood Cells Carry hemoglobin and oxygen and carbon dioxide. Do not have a nucleus and live only about 120 days. Can not repair themselves..

(39) 4.2 The Blood •Blood cells b) Leukocytes – White Blood cells Fight infection Five types – neutrophils, lymphocytes, eosinophils, basophils, and monocytes..

(40) 4.2 The Blood •The Blood cells •C). Thrombocytes – Platelets. –These are cell fragment that are formed in the bone marrow. –Clot Blood by sticking together.

(41) 4.3 The heart The Heart Cardiac muscle tissue The cardiac muscle contracts and relaxes 60-80 time per minute (heartbeat) Four parts •Right atrium •Right ventricle •Left atrium •Left ventricle.

(42) 4.3 The heart.


(44) 4.4 Cardiac Cycle • Heart is two pumps that work together, right and left half • Repetitive contraction (systole) and relaxation (diastole) of heart chambers • Blood moves through circulatory system from areas of higher to lower pressure. – Contraction of heart produces the pressure.

(45) 4.4 Cardiac Cycle

(46) Heart Sounds • First heart sound or “lubb” – Atrioventricular valves and surrounding fluid vibrates as valves close at beginning of ventricular systole. • Second heart sound or “dupp” – Results from closure of aortic and pulmonary valves at beginning of ventricular diastole, lasts longer.

(47) 5 BLOOD CIRCULATION The pulmonary circulation transports blood poor in oxygen from the heart to the lungs and then returns rich in oxygen The systemic circulation transports blood rich in oxygen from the heart to the cells and then returns poor in oxygen


(49) 6. The lymphatic system and the internal medium All cells of the body are bathed in fluid called intercellular or intersticial plasma (tissue fluid). The composition of the intersticial plasma must remain constant. The lymphatic system develop this function.

(50) 6. 1 The internal medium Intercellular fluid contains: water, proteins, wastes, salts and nutrients It helps to move materials between capillaries and body cells Exchange of materials occurs through this fluid The fluid is formed from blood plasma that diffuses out of the capillaries.

(51) 6.2 Lymphatic System Lymphatic system is composed of: lymph lymph vessels lymph capillaries lymph nodes (contain lymphocytes and macrophages) lymph organs/glands: spleen, tonsils, thymus.

(52) 6.2 Lymphatic System The lymphatic system Collects excess large particles and fluid Collects digested fats Particpates in the defense of our body.

(53) 6.2 Lymphatic System Spleen: - located near stomach - filters out bacteria - filters out old red blood cells from blood.

(54) 6.2 Lymphatic System Thymus: - located in the middle of the chest - provide growth and immunity - gets smaller when the organism gets older - secretes thymosin (helps lymphocytes to become mature).

(55) 6.2 Lymphatic System Lymphatic capillaries are tiny vessels of the lymphatic system.  Near each cell there are lymph capillaries that made up lymph vessels. When water and proteins enter lymph capillaries they are called lymph.  Lymph capillaries are made up of epithelial cells, they are more permeable than blood capillaries..

(56) 6.2 Lymphatic System Lymph nodes - play role in body defense against disease - produces lymphocytes.

(57) 6.2 Lymphatic System. Tonsils: trap and destroy bacteria.

(58) 6.2 Lymphatic System. The lymphatic system does not have pumping organ. Uses the same methods as veins to propel lymph: Pulsations of nearby arteries Contractions of muscle in the walls of the lymphatics Valves are present to prevent back flow.

(59) 7. The excretory system The excretion is the elimination of wastes from the cell activities Lungs exhale This wastes are eliminated through lungs, skin, and the excretory system.. skin. lungs. kidneys ureters urethra. carbon dioxide and water vapor. Sweat glands in skin release excess water and salts.. urinary bladder.

(60) 7. The excretory system The principal function of the kidney is to filter blood in order to remove cellular waste products from the body..

(61) 7.1 The excretory system anatomy The kidneys are bean shaped structures. • three layers: cortex, medulla and pelvis • filtering units called nephrons • renal artery and renal vein.

(62) 7.1 The excretory system anatomy The kidney can excrete waste products, such as : 1) urea a nitrogenous waste produced in the liver from the breakdown of protein. It is the main component of urine 2) uric acid usually produced from breakdown of DNA or RNA 3) creatinine waste product of muscle action..

(63) • The ureters are tubes that carry urine from the pelvis of the kidneys to the urinary bladder. • The urinary bladder temporarily stores urine until it is released from the body. • The urethra is the tube that carries urine from the urinary bladder to the outside of the body. • The outer end of the urethra is controlled by a circular muscle called a sphincter..

(64) 7.2 The excretory system: urine • Nephrons are the filtering units in the kidneys. • They clean and rebalance the blood to produce urine. to body • There approximately 1 loop of Henle million nephrons in each kidney. from body. To ureter. from other nephrons.

(65) 7.2 The excretory system: urine. • Nephrons clean the blood in a three-step process. • The first step is filtration of the blood. • Glomerulus: Network of capillaries • Bowman’s Capsule: Encases the glomerulus. 1. FILTRATION. Water, electrolytes, amino acids, glucose, urea, and other small molecules diffuse out of the blood, creating the filtrate.. • The body’s entire volume of blood is filtered every 45 min.

(66) 7.2 The excretory system: urine • The first step is filtration of the blood. • The second step is reabsorption of materials. from body. to body. loop of Henle. 2. REABSORPTION. As the filtrate enters the rest of the tubule, most of the materials are reabsorbed into the blood. Materials collecting not reabsorbed make duct up the urine, which flows into the loop of Henle.. from other nephrons.

(67) 7.2 The excretory system: urine • The first step is filtration of the blood. • The second step is reabsorption of materials. • The third step is excretion of materials. from body. 3. collecting duct to body. loop of Henle. from other nephrons. EXCRETION. In the loop of Henle, water can be reabsorbed one final time to reduce the volume of urine. The remaining urine flows into a collecting duct that leads to the ureter..

(68) 7.3 Another excretory organs · The sweat glands which expel the waste in form of sweat. · The lungs which expel the waste in form of carbon dioxide. · The liver which expels the waste in form of cellular rest..


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