Digestive System I

Question 1

3 things that contribute to ‘you are what you eat’

Answer 1

You are what you:
Digest
Absorb
Don’t Excrete

Question 2

3 Accessory organs in the digestive tract

Answer 2

Salivary glands
Liver
Pancreas
Gall bladder

Question 3

Explain ingestion process

Answer 3

Oral intake of substances

Question 4

Explain secretion process

Answer 4

Digestive juices - water, acid, emulsifiers, buffers and enzymes added

Question 5

Explain mixing and propulsion

Answer 5

Contraction and relaxation in walls to help mix and propel food

Question 6

Explain absorption

Answer 6

Substances pass through the walls of the alimentary canal into blood and lymph.

Question 7

explain digestion

Answer 7

Mechanical and chemical processes
break down ingested food and liquids
into absorbable substances

Question 8

Explain elimination

Answer 8

Excretion of water and indigestible materials

Question 9

4 layers of the gastrointestinal tract

Answer 9

1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa (peritoneum)

Question 10

Describe the role of microvilli

Answer 10

Increase the surface area for absorption

Question 11

Describe the role of goblet cells

Answer 11

secretion mucus to
lubricate food and protect against
digestive juice erosion

Question 12

What is meant by MALT

Answer 12

mucosa associated lymphoid tissue

Question 13

What percentage of the immune system is in the gut

Answer 13

70%

Question 14

Describe the role of GALT

Answer 14

GALT part of the
first line of defence
against ingested
pathogens.

25% of the intestine
mucosal mass.

Question 15

Locations of MALT in the body

Answer 15

tonsils,
oesophagus,
small intestine,
appendix and
large intestine.

Question 16

2 functions of involuntary smooth muscle contractions in the digestive tract

Answer 16

Mixing of food with digestive juices.
Propelling food (chyme / bolus) along the digestive tract
(peristalsis)

Question 17

Role of the peritoneum

Answer 17

is supplied with many blood
and lymph vessels.

It provides a physical
barrier to local spread of infection.

Question 18

Mucosa Epithelium what is it and key elements

Answer 18

Inner layer

Stomach and intestines have
- Microvilli (small intestines)
- Goblet cells
- Enteroendocrine cells

Question 19

Describe the mucosa’s second layer, lamina propria

Answer 19

connective tissue with GALT

Question 20

Mucosa’s muscularis mucosa

Answer 20

Thin layer of smooth muscle
Creates the villi

Question 21

Describe the submucosa layer

Answer 21

connective tissue layer that lies between the
mucosa and muscularis.

Contains the submucosal plexus - ‘brain of the gut’

Question 22

How is the submucosal plexus described?

Answer 22

Brain of the gut

Question 23

Describe the Muscularis Externa

Answer 23

• The mouth, pharynx, upper oesophagus and
  anal sphincter contain skeletal muscle to
  allow voluntary swallowing and defecation.

The GIT is mostly smooth muscle

Question 24

Myenteric plexus and nervous system

Answer 24

sympathetic and
parasympathetic nerve fibres

Controls strength and frequency
of muscle contraction: gut motility.

Question 25

Submucosal plexus and nervous system

Answer 25

controls digestive secretions
and detects sensory information.

Question 26

2 ways sensory neurons receive info about environmental changes

Answer 26

Motor neurons (outgoing / action
signal)
control peristalsis & secretions.

Sensory neurons (incoming
signal) receive information
about the mucosal environment:
chemoreceptors and stretch
receptors.

Question 27

2 veins that drain the digestive system

Answer 27

The portal vein drains the lower oesophagus,
stomach, pancreas, small and large intestine,
upper rectum and spleen.

The iliac veins drain the lower part of the
rectum and anal canal.

Question 28

What is meant by peristalsis

Answer 28

Wave like contractions that propel food (chyme / bolus) along the digestive tract

Question 29

4 functions of the oral cavity

Answer 29

Mastication
Speech
Taste
Swallowing

Question 30

2 glands that produce saliva

Answer 30

Sublingual gland
Submandibular gland

Question 31

How is saliva production affected by parasympathetic nervous system?

Answer 31

Decreased