Histology of Digestive system

Question 1

The main function of the gastrointestinal tract

Answer 1

break down food for absorption into the body.

Question 2

this is done in five main phases;

Answer 2

: Ingestion, Fragmentation, Digestion, Absorption, Elimination

Question 3

There are four distinct layers of the tract:

Answer 3

Muscularis propria
Mucosa
Submucosa
adventitia.

Question 4

Gastrointestinal system

Answer 4

is basically a muscular tube that is lined with a mucous membrane which is regionally specialized to serve the changing functions of the system from mouth to anus.

Question 5

mucous membrane

Answer 5

is protective, secretory, absorptive or a combination of these

Question 6

tissue that gives strength to wall of the tract and assist in moving food along.This tissue is arranged differently throughout the tract

Answer 6

Muscle tissue

Question 7

Lymphoid tissue.

Answer 7

Lymphoid tissue is associated with the tract due to the system being continuous with the external environment and this being a potential entry points for pathogens.

Question 8

The mucosa made up of 3 components are?

Answer 8

epithelium
supporting lamina propria
smooth muscle- muscularis mucosae

Question 9

The mucous components produces what?

Answer 9

local movements and folding of mucosa.

Question 10

At four points along the tract the mucosa undergoes abrupt transitions:

Answer 10

Gastro-oesophageal junction- Stratified squamous epithelium in the oesophagus becomes simple columnar epithelium in the stomach

Gastroduodenal junction- long pits and short, coiled glands in the pyloric stomach to villi and crypts in the duodenum

Ileocecal junction- villi with crypts in the small intestine to only crypts in the large intestine

Rectoanal junction-simple columnar epithelium in the rectum to stratified squamous epithelium in the anus- for absorption of fliud

Question 11

function of crypts

Answer 11

allow the intestine to regenerate a new cell forming a new layer.

Question 12

layer of loose collagenous tissue

Answer 12

SUBMUCOSA

supports mucosa
contains blood vessels and lymphatic and nerves

Question 13

Mascular propria

Answer 13

muscular wall propria consist of smooth muscle fibers.

This is usually arranged as:
Inner circular layer
Outer longitudinal layer

Question 14

Action of the two layers, which are at right angles to each other, is to contribute

Answer 14

to peristaltic contraction

Question 15

An outer layer of loose supporting tissue

Answer 15

Adventitia

Question 16

layer Referred to as serosa, where the gut lines the peritoneal cavity, and is lined by mesothelium.

Answer 16

adventitia

Question 17

adventitia conducts

Answer 17

Conducts major vessels, and nerves and contains variable amounts of adipose tissue.

Question 18

what initiates the contractile of smooth muscle

Answer 18

Contraction of smooth muscle is initiated by pacemaker cells known as the interstitial cells of Cajal.

Question 19

Autonomic Innervation

Answer 19

regulation of glandular secretions and smooth muscle of the gut is mediated via the intrinsic nervous system.
This has sympathetic and par

Question 20

In the submucosa there are clusters of parasympathetic ganglion cells:

Answer 20

Submucosal plexus- a collection of small clusters of parasympathetic ganglia which supply the mucosal glands and smooth muscle of muscularis mucosae.

Myenteric plexus- a collection of larger clusters of parasympathetic ganglia which are found between the two layers of the muscularis propria and supplies surrounding smooth muscle.

Question 21

protective layers found in the oral cavity, pharynx, oesophagus, and anal canal.

Answer 21

stratified squamous epithelium.

Stratified mucosal lining is well suited to sites of potential frictional trauma – such as those associated with mastication, swallowing or defecation.

Question 22

secretory

Answer 22

Only occurs in the stomach.
Has long tubular glands that are simple or branched.
These glands produce various combinations of acid and digestive enzymes to facilitate digestion and also secrete mucous to protect the mucosa from injury.

Question 23

Absorptive

Answer 23

Typically found in the small intestine.

Question 24

Mucosa is arranged into small finger-like projections known as ………………………………………i which increase the surface area of the mucosa.

Answer 24

Villi

Question 25

Absorptive/Protective

Answer 25

Lines entire large intestine.
Mucosa is arranged in tightly packed straight tubular glands which have specialized cells for water absorption.
Also has mucous-secreting goblet cells to lubricate the passage of faeces.