Human Physiology: Digestion

Question 1

What is nutrition?

Answer 1

Is the biochemical and physiological process by which living organisms uses food to support its life

Question 2

What is Digestion?

Answer 2

Breakdown of large insoluble food molecules into small soluble molecules that can be absorbed.

Question 3

Explain the role of stomach Digestion

Answer 3

Gastric glands in the wall of stmoachs secrete Gastric juice, which contains hydrochloric acid and protease enzyme (pepsin)and renin (digests protein carcinogen to carseine in milk)
Goblet cells in the stomach lining secrete mucus
Mucus prevents autolysis
Food becomes chyme

Question 4

Role of pancreas in Digestion

Answer 4

Produces insulin and glucagon involved in glucose metabolism
Produce pancreatic juice that contain three enzymes; lipase, amylase, endopeptidase

Question 5

Role of small intestine

Answer 5

Chyme meets bile in the duodenum
Bile is strongly alkaline (activates enzyme) and neutralises the acidity of the chyme.
It also lowers the surface tension of large flat globules, breaking them down into tiny droplets - emulsification.which increases surface area for enzymatic activity

Question 6

Pancreatic juice contains?

Answer 6

Amylase- catalyses the hydrolysis of of starch into maltose
Lipase- catalyses the hydrolysis of fats/lipids and oil to fatty acids and glycerol
Proteases(trypsinogen)- catalyses the hydrolysis of proteins into Polypeptide to shorter length peptide to free amino acids.
Sodium hydrogen carbonate- -neutralises the acidity of the chyme
Nucleases- digests nucleic acids rna and Dna into nucleosides

Question 7

structural adaptations of small intestine to its function

Answer 7

Large and highly coiled to provide large surface area and long time for max absorption of digested food.
The wall of the ileum has numerous villi which contains several blood capillaries which increases the surface area for max absorption of digested food
The wall has lacteal for absorption and transport of fatty acids and glycerol
They have thin Epithelium cell for faster absorption of digested food
They have glands, that produce intestinal juice which contains digestive enzymes that help complete the process of digestion.
The ileum has gone through cells that produce Mucus which coats the intestinal lining preventing it from abbresion and autolysis by digestive enzymes.

Question 8

Functions of small intestine

Answer 8

Completion of digestion
Absorption of digested foods

Question 9

intestinal juice produced by the illeum and its role

Answer 9

Secretes intestinal juice which contains enzyme
Maltase- digests maltose into glucose
Peptidase- digests peptides into amino acids
Sucrase-digests sucrose into glucose and fructose
Lactase- digests lactose into galactose and glucose
Lipase- digests lipase into fatty acids and glycerol

Question 10

Role of liver

Answer 10

Detoxification
Bile production
Metabolism
Haemoglobin breakdown

Question 11

Role of Villi

Answer 11

Provide a huge surface area for absorption
Lacteal- triglycerides pass for transport to body cells
Network of capillaries- Provide large surface area for uptake of amino acid, monossacharides,
Epithelium cells - packed with mitochondria the sources of atp for active uptake across the plasma membrane. Has pump proteins to actively transport nutrients across across the plasma membrane. Mucus from the goblet Cells to lubricate movements of digested food among the villi

Question 12

List transport mechanisms used by epithelial cells to absorb nutrients?

Answer 12

Simple diffusion
Facilitated diffusion
Membrane pumps
Endocytosis

Question 13

Define
ingestion, Digestion, Absorption, Assimilation, Egestion

Question 14

Define peristalsis and explain the process