Digestive System And Metabolism

Question 1

Digestive system Functions

Answer 1

1) Ingestion: Putting food in mouth (conscious thought)
2) mechanical processing: Crushing food (Teeth and tongue)
3) digestion: chemical breakdown of food into small particles for absorption
4) secretion: release of substances (saliva, mucous, enzymes)
5) absorption: When nutrients cross Digestive epithelium into interstitial fluid of digestive tract
6) excretion: removal of waste products after absorbing everything useful

Question 2

Digestive tract layers

Answer 2

1) Mucosa: stratified squamous in oral cavity, pharynx, esophagus, anus; simple columnar in rest
2) submucosal: large blood vessels and lymphatics
3) muscularis externa: circular and longitudinal smooth muscle cells
4) serosa: serous membrane that covers all internal organs

Question 3

Digestive tract organs

Answer 3

Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine

Question 4

Digestive tract accessory organs

Answer 4

Teeth, tongue, glandular organs (pancreas, liver salivary glands)

Question 5

Muscularis mucosae

Answer 5

Smooth muscle cells in laminapropia

Question 6

Muscularis externa (layer)

Answer 6

Control mechanical processing and peristalsis of food which is controlled by enteric nervous system

Question 7

Peristalsis

Answer 7

Series of defined muscular contraction that moves bolus (food) throughout organ

Question 8

Segmentation

Answer 8

Contraction that hold the bolus in one place to churn and fragment it

Question 9

Oral cavity (Start of ingestion)

Answer 9

1) Analysis of food before swallowing
2) mechanical processing
3) lubrication
4) beginning of digestion
- (Tongue, salivary glands, larynx, esophagus)
- stratified squamous epithelium

Question 10

Tongue

Answer 10

mechanical compression assist in chewing Sensory input (taste, temperature, touch) secretion of mucins/lingual lipase (lipid digestion)

Question 11

Salivary glands

Answer 11

parotid gland‘s: produce enzyme rich serous secretions and salivary amylase that breaks down starches

sublingual gland’s: produce watery mucous secretions for lubrication

submandibular gland‘s: contains mucous cells that secrete mucins, glycoproteins, and buffers ALSO has serous cells that secrete amylase

Question 12

Saliva functions

Answer 12

• Lubrication of food
• solubilizing of chemicals which can stimulate sensory info
• beginning of digestion (chemical processing (amylase and lipase)) (mechanical processing (grinding food))

Question 13

Cardia of stomach

Answer 13

Contain mucous glands that secrete alkaline mucus to help protect esophagus from acidic contents of stomach splashing out

Question 14

Body and fundus of stomach

Answer 14

Contain gastric (stomach) glands that produce acids and enzymes involved in digestion

Question 15

Pyloris of stomach

Answer 15

Pyloric canal empties into duodenum via pyloric sphincter and secrete alkaline mucus and hormones (gastric and stimulate gastric glands)
Secretion of mucus and gastric stimulate parietal and chief cells

Question 16

Gastric glands (two types)

Answer 16

• Parietal cells: secrete intrinsic factor and HCl

- Chief cells: secrete pepsinogen

Question 17

Intrinsic factor (glycoprotein)

Answer 17

A substance secreted by the stomach which enables the body to absorb vitamin B 12