Week 1-Human Digestive & Absorption, Anatomical Structures and Physiological Structures

Question 1

GIT

Answer 1

The gastrointestinal tract - mouth, esophagus, stomach, small intestine, large intestine, rectum anus
accessory organs - liver, pancreas and gall bladder

Question 2

Oral Cavity (mouth)

Answer 2

• chewing increases surface area
• when mixed with saliva food becomes bolus
• saliva

Question 3

Saliva

Answer 3

– Lysozymes: Break down bacteria
– Mucus: Lubricates and holds bolus together
– Salivary amylase: starts breaking down starch
– Lingual lipase: starts breaking down triglycerides

Question 4

Sphincters

Answer 4

– Lower esophageal sphincter
– Pyloric sphincter
– Sphincter of Oddi
– Ileocecal sphincter (or “valve”) – Anal sphincter

Question 5

Lower esophageal sphincter

Answer 5

Prevent backflow (reflux) of stomach contents into esophagus

Question 6

Pyloric sphincter

Answer 6

Control the flow of stomach contents into the small intestine

Question 7

Sphincter of Oddi

Answer 7

Control the flow of bile from the common bile duct into the small intestine

Question 8

Ileocecal sphincter

Answer 8

Prevent the contents of the large intestine from reentering the small intestine

Question 9

Anal sphincters

Answer 9

Prevents defecation until person desires to do so

Question 10

GIT Motility

Answer 10

1. Peristalsis
2. Segmentation
3. Mass movements
4. Elimination via sphincters

Question 11

Peristalsis

Answer 11

Contractions of the GIT wall muscle for movement of bolus and chyme
• Peristalsis is triggered by the autonomous nervous
system. Hydration and bulk of feces play a role:
stretching of intestinal wall promotes peristalsis

Question 12

Segmentation

Answer 12

Back and forth movement to allow breaking down

of bolus and chyme into smaller particles so enzymes can access

Question 13

Mass Movement

Answer 13

Peristalsis over widespread area

Question 14

Digestion

Answer 14

Process of breaking down foods into molecules that can be absorbed by erythrocytes and delivered into blood and lymphatic system

Question 15

Absorption

Answer 15

uptake of monomers and micro-nutrients from the lumen of the GIT through absorption cells (enterocytes) into blood or lymph for transport to organs/cells
Ageing= decreased HCL, therefore decreased absorption and digestion

Question 16

Pathway of food

Answer 16

• Food mixed in the bolus goes through lower
eosophageal sphincter into stomach
• Mixed with stomach secretions becomes chyme
• Pyloric sphincter allows chyme into the small intestine
• Gastric inhibitory peptide (GIP) slows the release of
the chyme from the stomach into the small intestine

Question 17

Gastrin:

Answer 17

Hormone that controls release of HCl and

pepsinogen

Question 18

Parietal cells

Answer 18

produce hydrochloric acid (HCl)

Question 19

HCL

Answer 19

• Denatures proteins
• Destroys bacteria and viruses
• Converts pepsinogen into the active form pepsin:
enzyme for protein digestion
• Aids in minerals absorption
• Chief cells: produce and release gastric lipase

Question 20

Mucus:

Answer 20

Protects the stomach from “being digested” by HCL

Question 21

Chief cells

Answer 21

produce and release gastric lipase

Question 22

Small intestine

Answer 22

• Site of most of the digestive and absorptive processes
• Three sections: duodenum, jejunum and ileum: a total
of 6m in length
• Villi and microvilli on the intestinal wall: increase the
surface area of the lumen by 600 times to optimise the
absorption capacity

Question 23

Goblet cells:

Answer 23

produce mucus

Question 24

Endocrine cells

Answer 24

produce hormones

Question 25

Enterocytes

Answer 25

absorb nutrients and produce

metabolism enzymes