Human Physiology 3

Question 1

What are 4 steps of the digestive process?

Answer 1

ingestion (eating/drinking)
digestion (breakdown of macromolecules into smaller ones that can be absorbed, mechanical/chemical)
absorption (digested nutrients absorbed into blood except lipids)
egestion (elimination of undigested material, feces)

Question 2

What are the main structures of the digestive system?

Answer 2

mouth, esophagus, stomach (cardiac, pyloric sphincter), small intestine, pancreas, liver (gallbladder), large intestine

Question 3

What is the purpose of the mouth?

Answer 3

mechanical digestion of teeth and tongue (increased SA), chemical digestion by enzymes in saliva (water and amylase, which begins starch digestion)

Question 4

What is the purpose of the esophagus?

Answer 4

hollow muscular tube connecting mouth to stomach, movement of food by peristalsis (contraction and relaxation), epiglottis shunts food into esophagus during swallowing, keep out of lungs

Question 5

What is the purpose of the stomach?

Answer 5

J shape, under diaphragm (gastric = stomach)
store food, mechanical digestion (churn), liquefying chyme to increase SA (acid breaks down connective tissue), stomach acid (HCl, denatures enzymes and proteins in food, kills pathogens), protein digestion by pepsin (pepsinogen activated by HCl)

Question 6

What is the purpose of the small intestine?

Answer 6

most chemical digestion takes place here (duodenum), herbivores have longest, carnivores have shortest, majority of absorption (villi + microvilli), capillary (monosaccharides/carbs and amino acids/proteins absorbed into blood), lacteals (lymph vessels that absorb lipids)

Question 7

What is the purpose of the pancreas?

Answer 7

Produces enzymes to breakdown proteins, carbohydrates, and lipids, produces bicarbonate (HCO3) to buffer gastric juices in duodenum (neutralize the HCl from stomach), connected to small intestine

Question 8

What is the purpose of the liver?

Answer 8

produces bile for fat digestion (bile stored in gallbladder), storage of glycogen and vitamins, breaks down amino acids into urea, detoxifies harmful compounds, bile salts emulsify/breakdown fat globules into smaller droplets

Question 9

What is the purpose of the large intestine?

Answer 9

Waste removal, reabsorb water from waste, absorbs some salts, minerals, vitamins, cellulose (polysaccharide makes up plant walls), fibre allows for more frequent bowel movement