Digestion Syllabus Flashcards

Pregunta	Respuesta
Define Chemical digestion	The breaking down of food into smaller nutrients that can be absorbed by the body cells (saliva and stomach acid etc)
Define Mechanical digestion	Physically breaking down food into smaller pieces (teeth and stomach churning etc)
Six basic activities of the digestive system	1) Ingestion of food and water 2) Mechanical digestion of food 3) Chemical digestion of food 4) Movement of food along the alimentary canal 5) Absorption of digested food and water into the blood & lymph 6) Elimination of material that is not absorbed
Label a diagram of the digestive system	See page 109
Describe Structure and function of each part of the digestive system	See page 109
Identify the four types of teeth and describe their functions	See page 110 Incisors - Chisel shaped for biting and cutting (eating and apple) Canines - Tearing food Premolars - Two on each side of jaw. Broad crowns for crushing and grinding Molars - Broad crowns for crushing and grinding food
Explain peristalsis	Food is pushed along the alimentary canal by peristalsis. One section contracts whilst another relaxes to push food along the tube. Longitudinal and circular muscles work together to cause peristalsis. (See page 111)
Identify and explain the type of digestion occurring in the mouth	Mechanical: Chewing - breaking down food with teeth Bolus - forming food into ball by tongue Swallowing - tongue pushes bolus into larynx Chemical: Salivary amylase - produces Polysaccharides which lead to sugars
Identify and explain the type of digestion occurring in the stomach	Mechanical: Muscular churning - mixes food with gastric juice and forms chyme Rennin - (infants only) curdles milk Chemical: Hydrochloric acid - activates pepsiongen which leads to pepsin Pepsin - proteins which leads to polypeptides (Pepsionogen = inactive form of pepsin) (Pepsin = only activated when HCL is present in stomach) Absorption: Limited absorption of water, glucose, alcohol and some drugs
Identify and explain the type of digestion occurring in the small intestine	Chemical: Amylases - disaccharides to monosaccharides Lipase - Fats and oils to fatty acids and glycerol Peptidases - peptides to amino acids Absorption: Absorption of digested material into the blood and lymph though villi
Draw and label a diagram of the mucosa wall of the stomach	See page 112
Describe where bile is made, stored, what it is made up of and its function	Made - Secreted by glands in liver Stored - Gall bladder Made up of - water, bile salts and cholesterol Function - bile salts emulsify lipids, forming small globules with large surface area
Identify the pancreas and describe each of the enzymes it secretes and its function	Left side between liver and stomach Ducts carrying pancreatic juice enter duodenum. Pancreatic juice - water, sodium hydrogen carbonate, pancreatic amylase, protease, lipase and nucleotides
Draw and label a diagram of a villi	See page 114
Explain how each nutrient is absorbed through the villi	Simple sugars - (glucose) active transport. Pass through cells on outside of villi and into blood capillaries Water and water soluble vitamins - Absorbed into blood capillaries by diffusion Fatty acids and glycerol - simple diffusion. In cells of villi, fatty acids and glycerol recombine to form fats. Tiny fat droplets enter lacteals Amino acids - absorbed by active transport into blood capillaries.
Structure and function of a lacteal	Absorbs fat from digested food. Lymph capillary in villus. Surrounded by network of blood capillaries.
Explain where nutrients are taken after they are absorbed	Blood capillaries. Fatty acids recombine in the cells of the villi to form fats and, along with the fat-soluble vitamins, enter the lacteals. Substances absorbed into blood capillaries are carried by the hepatic portal vein to the liver. Here they can be removed for further processing, or remain in blood to be carried to other body cells. Substances absorbed into lacteals are transported into the lymph system, which eventually empties into the blood through veins in upper chest
Distinguish between elimination and exctretion	Excretion - removal of metabolic waste = waste that has been produced by chemical activity of the body cells. Elimination - Except for bile pigments, contents of faeces are not metabolic waste. So defecation is elimination and not excretion
Identify parts and functions of the large intestine	See page 116
List each of the digestive enzymes and describe where they are produced, what nutrient each acts on and what nutrient is broken down to	See Table 9.1 on page 117
Describe constipation	Constipation - Contents of large intestine remain there for a long time. Water is absorbed and faces become harder and drier. Caused by lack of roughage in diet (cellulose or insoluble fibre). No enzymes to digest cellulose but it is important because it stimulates movement of alimentary canal.
Describe diarrhoea	Frequent defecation of watery faeces. Caused by irritation of small or large intestine, which increases peristalsis so the contents move through without being absorbed of water etc. Irritation caused by bacterial or viral infection
Describe bowel cancer	Uncontrollable growth of cells in wall of large intestine. Risks involve: diet, alcohol, smoking, red meat, low fibre (fruit and veg), overweight, physical inactivity
Coeliac disease	Unable to tolerate protein called gluten, which is found in wheat, rye and barley. If people eat food containing gluten, immune system destroys or damages villi in small intestine. Without villi, nutrients can't be absorbed and person becomes malnourished.

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