NUTRITION: THE DIGESTIVE AND RESPIRATORY SYSTEMS

1 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS nutrition : THE DIGESTIVE AND RESPIRATORY SYSTEMS Biology nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 2 Human nutrition The DIGESTIVE system The DIGESTIVE process in the mouth The DIGESTIVE process in the stomach The DIGESTIVE process in the small intestine Liver and pancreas From food to nutrients Food absorption The DIGESTIVE process in the large intestine The RESPIRATORY system Gas exchange Pulmonary ventilation Health and illnesses of the DIGESTIVE system Health and illnesses of the RESPIRATORY system nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS HUMAN nutrition Oxford University Press Espa a, S. A. Biology 3 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 4 DIGESTIVE , RESPIRATORY , excretory and circulatory system all play a role in nutrition . DIGESTIVE system RESPIRATORY system Excretory system Circulatory system nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS THE DIGESTIVE system Oxford University Press Espa a, S.

2 A. Biology 5 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 6 salivary glands pharynx gall bladder appendix rectum anus mouth esophagus salivary glands diaphragm liver stomach pancreas large intestine small intestine An inner cell layer called a mucous membrane makes up the gastrointestinal tract. It s internally protected by a lubricant substance called mucus and it s surrounded by muscular layers. When these layers contract they push food down the DIGESTIVE tract. The mucosa in the stomach and intestine contain glands that secrete a protective mucous and others that secrete DIGESTIVE juices. nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS THE DIGESTIVE PROCESS IN THE MOUTH Oxford University Press Espa a, S. A. Biology 7 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 8 Salivation parotid submandibular sublingual premolars incisors Chewing canines molars tongue bolus nasal pasages soft palate epiglottis larynx pharynx esophagus Swallowing nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS THE DIGESTIVE PROCESS IN THE STOMACH Oxford University Press Espa a, S.

3 A. Biology 9 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 10 esophagus cardia layers of muscle pylorus Gastric juices contain pepsin, an enzyme that starts protein digestion, and hydrochloric acid, which has two functions. It activates pepsin enzymes and supports them by helping the disintegration of food fibres, and destroys bacteria that may be present in food. The inner layer is covered in mucus that protects it from the effects of hydrochloric acid and enzymes. The stomach is formed by three muscular layers, which perform massaging motions to mix the chyme. nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS THE DIGESTIVE system IN THE SMALL INTESTINE Oxford University Press Espa a, S. A. Biology 11 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 12 The small intestine releases DIGESTIVE secretions with enzymes that break down different molecules. Stomach Pylorus Large intestine Ileocecal valve Duodenum Short section (25 cm) shaped like a horseshoe Jejunum The longest part of the small intestine Ileum The final section that ends in the large intestine nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS LIVER AND PANCREAS Oxford University Press Espa a, S.

4 A. Biology 13 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 14 The liver produces bile, which is stored in the gall bladder. Bile intervenes in the emulsification of fats: fats are transformed into very small drops, helping enzymes found in DIGESTIVE juices break down fats. The pancreas secretes pancreatic juice through the ampulla of Vater, which contains enzymes capable of digesting the different types of molecules present in foods. stomach pancreas duodenum ampulla of Vater gall bladder liver esophagus nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS FROM FOOD TO NUTRIENTS Oxford University Press Espa a, S. A. Biology 15 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 16 Digested by Digested by Digested by Digested by Result in Result in Result in Result in Starch Sucrose Fats Proteins Amylase (s, i, p) Maltase (i) Maltose Glucose molecules Sacarasa (i) Lipase (i, p) Pepsin (g) Tripsin (p) Erepsin (i) Peptide Short peptide Amino acids Glycerine molecules and fatty acids Fructose and glucose molecules Foods Enzymes Nutrients nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS FOOD ABSORPTION Oxford University Press Espa a, S.

5 A. Biology 17 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 18 Food absorption refers to the passage of nutrients to our blood. This allows those nutrients to be distributed across the whole organism. It takes place mainly in the small intestine. In order to increase the surface area for the absorption of nutrients, the inner layer is full of villi and intestinal folds, and the plasma membrane that forms villi has extra creases known as microvilli. small intestine intestinal folds lymph capillary intestinal gland capillaries intestinal vili microvili intestinal mucous cells nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS THE DIGESTIVE PROCESS IN THE LARGE INTESTINE Oxford University Press Espa a, S. A. Biology 19 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 20 Absorption of most water and minerals takes place in the large intestine; faeces compact to form stools. ileocecal valve appendix Rectum.

6 This is the final section that ends in the anus. anus Colon. This part of the large intestine is where symbiotic bacteria of the intestinal flora develop and certain vitamins, such as B12 and K, are produced. ascending colon descending colon Cecum. This is the first section, it s shaped like a bag and has a narrow extension, the appendix. nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS THE RESPIRATORY system Oxford University Press Espa a, S. A. Biology 21 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 22 The RESPIRATORY system obtains oxygen from the air and provides it to the blood in the circulatory system . Blood carries the oxygen into the cells and takes away carbon dioxide so it can be released. diaphragm bronchiole bronchi left lung epiglottis pharynx nasal cavity larynx trachea right lung heart nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS GAS EXCHANGE Oxford University Press Espa a, S. A. Biology 23 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S.

7 A. Biology 24 Oxygen is exchanged between air and blood by the process of diffusion: oxygen travels from the area where its concentration is greater to the area where it is lower. Oxygen concentration is higher in our alveoli than in our blood. Carbon dioxide concentration is lower in our alveoli than in our blood. The oxygen found in air goes into the blood, after passing through the alveolar wall and the wall of the capillary, to be transported to the body's cells. El di xido de carbono de la sangre pasa a los alv olos, donde se mezcla con el aire que contienen y es expulsado en la espiraci n. O2 CO2 CO2 CO2 CO2 O2 O2 O2 air pulmonary alveoli pulmonary capillary nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS PULMONARY VENTILATION Oxford University Press Espa a, S. A. Biology 25 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 26 Inspiration Expiration Air enters Air exits Ribcage increases its volume The diaphragm contracts, flattens and lowers itself Ribcage decreases its volume The diaphragm relaxes, curves and rises nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS HEALTH AND ILLNESSES OF THE DIGESTIVE system Oxford University Press Espa a, S.

8 A. Biology 27 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 28 Recommendations to look after the organs of the DIGESTIVE system : Chew food slowly, making sure that all food is crushed properly. Brush your teeth after each meal in order to eliminate any small pieces of food. Visit the dentist at least once a year. Do not eat or drink foods that are very hot. Wash your hands before eating or preparing food. Do not eat out of meal times so that the DIGESTIVE system doesn t function non-stop. Ensure foods you eat are in perfect condition in order to prevent food poisoning. Eat foods that have fibre as they help intestinal movements. Do not consume alcohol. The illnesses of the DIGESTIVE system can affect the mouth, like cavities or gingivitis; the stomach, like gastritis or ulcers; the liver, like hepatitis or cirrhosis, and the intestine, like gastroenteritis, appendicitis, constipation or colon cancer. ulcers nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS HEALTH AND ILLNESSES OF THE RESPIRATORY system Oxford University Press Espa a, S.

9 A. Biology 29 nutrition : The DIGESTIVE and RESPIRATORY SYSTEMS Oxford University Press Espa a, S. A. Biology 30 Recommendations to look after the RESPIRATORY organs: Do not smoke. Try to avoid sudden changes of temperature as such changes increase the risk of contracting RESPIRATORY illnesses. Do physical exercise regularly. Try to avoid being in contact with dust and atmospheric contaminants. Try to breathe through your nose. Illnesses related to the RESPIRATORY system are caused by infections (infectious), like nasal catarrh, bronchitis or flu, or by an inflammation of the mucosa (non-infectious), like aphonia, asthma, emphysema or lung cancer.