13640040
| Question | Answer |
| What are the stages of digestion? (5) | Ingestion, digestion, absorption, metabolism, excretion |
| What is digestion? where does it occur? | Breaking down food into small chemical units Occurs in stomach + small int. |
| What is absorption? where does it occur? | Chem. units > blood > liver Occurs in small intestine |
| What is metabolism? | Chem. units converted into energy, takes place mainly in liver |
| What is excretion? | Removing any indigestible material |
| What are the functions of the oral / buccal cavity or mouth? | Pick up food, break it up into small boluses, lubricate food |
| What are the functions of the tongue? | - Aid food ingestion - Carry receptors (taste buds) for sensation of taste or gustation - Help form food bolus ready for swallowing - Groom fur - Assist thermoregulation - Produce vocalisation |
| What are the functions of saliva? | - Chemical digestion: breaks down starch via salivary amylase - Helps chew / swallow - Solvent effect: dissolves food + allows tongue to taste - Cleaning effect: washes away food debris / bacteria remaining in mouth |
| What is the pharynx? | Crossover point between respiratory / digestive systems, muscular tube lined w/ mucus membrane, connecting back of nasal + oral cavities w/ oesophagus, larynx and trachea |
| What is the purpose of the pharynx? | Conveys food from mouth > oesophagus via deglutition / swallowing |
| What is the oesophagus? | Simple tube carrying food from pharynx > stomach |
| What is the structure of the oesophagus? | Walls lined w/ stratified squamous epithelium arranged in longitudinal folds, protecting against damage by food + allowing widthways expansion as food boluses pass down Within walls are circular + longitudinal bands of smooth muscle fibres, contraction brings peristaltic waves forcing food along tube |
| What is a monogastric stomach and what is its function? | Simple e.g. dog, cat Food reservoir, break up food and mix w/ gastric juices, begin process of protein digestion |
| What are the two muscular movements? | Peristalsis - contractions pushing food through stomach Rhythmic segmentation - breaks and mixes food boluses |
| What are the 3 regions of the stomach? | Cardia, fundus + pylorus |
| What does distention of the stomach do? | Stimulates secretion of hormone gastrin from walls > initiate gastric juice production |
| Walls lined with mucous membrane? | Gastric mucosa found in deep longitudinal folds (rugae) which flatten out when stomach is filled w/ food |
| Within mucosa are gastric pits what are the 3 cell types responsible for secreting gastric juices? | Goblet cells, chief cells and parietal cells |
| What are their individual functions? | GC - in parts of stomach, secrete mucus to lubricate food + protect stomach wall from damage by digestive enzymes CC - in fundus, secrete pepsinogen as precursor to active enzyme pepsin, pepsin breaks proteins to peptides PC - in fundus, secrete hydrochloric acid > acid pH enabling pepsin to work effectively |
| What is gastric emptying? | Food in stomach broken up, partially digested = chyme (liquid with acid pH), released through pyloric sphincter > duodenum where digestion continues |
| What is the small intestines function? | Major site of enzyme digestion + absorption, food mixes w/ digestive juices (by peristalsis + rhythmic segmentation) |
| What is the structure of the small intestine? | Divided into duodenum, jejunum, lienue Epithelial layer folded into millions of folds (villi) increase surface area to max. efficiency of digestive and absorptive processes |
| What is the pancreas and its function? | Secretions essential to digestive process, described as extrinsic gland (endocrine + exocrine parts = mixed gland) Exocrine part secretes digestive enzymes + bicarbonate into duodenum via pancreatic duct |
| What is the gall bladder? | Bile reservoir (produced by liver), contains salts needed for fat digestion and secreted into duodenum via common bile duct |
| What is the livers function? and how do substances get there? | - Carbohydrate / protein / fat metabolism - Bile formation - Vitamin / iron storage - Detoxification of substances Via. hepatic portal vein |
| What is the structure of the large intestine? | Similar structure to small int. But no digestive glands, no villi but does have goblet cells which secrete mucus lubricating faeces as it passes through |
| What is the main absorption site? | Villi of the small intestine |
| How is absorption made efficent? | - Long length of small int. - Internal surface area increase by villi + epithelial ‘brush border’ - Blood capillaries + lacteals |
| What is the process of absorption? | Amino acids + simple sugars absorbed by blood capillaries > carried by hepatic portal vein > liver |
| What is the structure of villi? | - Tiny projections protruding from epithelial lining of the intestinal wall - Provide large surface area > allows faster absorption and more efficiency - Each villi has capillary network (absorbs glucose, amino acids, water soluble vitamins / minerals) + fine lymphatic vessels |
| How is blood glucose regulated? | Insulin: produced by the pancreas (response to high blood glucose) > cells absorb glucose out of the blood (response to insulin) > lowers levels Glucagon: regulates glucose + fats, a response to low blood sugar levels |
| What are the symptoms of ingesting foreign bodies? | Vomiting, regurgitation, lethargy, loss of appetite, abdominal pain, drooling, dehydration, diarrhoea |
| How does the body try to push the foreign object out? | Peristaltic motion of muscular gut trying to push foreign object along can build up pressure around it resulting in blood supply to gut being compromised > devitalised |
| What happens if the body fails? | Gut wall can rupture > bacteria + ingesta > abdomen = severe pain, peritonitis, shock, death |
| What is ruminant bloat? what are the symptoms? | Gas build up from digestion in rumen caused by obstructed gullet, if the animal cannot burp, foam developing over rumen liquid preventing escape Symptoms: distended left abdomen, pain, discomfort, bellowing |
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