Digestive sys

Question 1

4 main tunics of alimentary tract

Answer 1

Out->in

1. Serosa/ adventitia
2. Muscularis externa
3. Submucosa
4. Mucosa

Question 2

Name 3 innermost layers of mucosa layer

Answer 2

1. Muscularis mucosae
2. Lamina propria
3. Epithelium

Question 3

2-3 muscles on muscularis externa

Answer 3

1. Outer longitudinal fibres
2. Inner circular fibres
   3* Innermost oblique

Question 4

Where is muscularis externa composed of skeletal muscle (voluntary)?

Answer 4

Mouth, pharynx, upper oesophagus, anus

Question 5

2 nerve plexus and locations

Answer 5

1. Submucosal (Meissner’s) plexus in submucosa

2. Myenteric (Aurbach’s) plexus in b/w 2 muscles in muscularis externa

Question 6

What initiates defecation reflex?

Answer 6

1. Distension/strectch of rectal wall by faeces
2. parasympathetic stimulated => colon & rectum contract, internal sphincter relax
3. Voluntary movements assist in expel faeces: relax external sphincter
4. Ab. cavity pressure, bc inspiration, increases and ab. muscles contract

Question 7

What organs do greater and lesser ommentum attach to?

Answer 7

Greater: greater curvature of stomach to transeverse colon
lesser: stomach & duodenum to liver

Question 8

WHat organs do falciform ligament, mesntery, mesolon attach to?

Answer 8

Falciform lig: liver to abd. wall

mesentery: Small intestine to post ab. wall
mesocolon: LI to post abd. wall

Question 9

diff b/w intrinsic & extrinsic muscles in tongue

Answer 9

int: muscles lie w/n tongue
ext: “ attach to bones of skull

Question 10

name of hole in diaphgragm & why

Answer 10

oesophageal hiatus&raquo_space; so oesophagus can pass through to get to stomach

Question 11

secrettions of submucosa & why?

Answer 11

mucous&raquo_space; lubricate passing food

Question 12

Name the 3 salivary glands and what they secrete?

Answer 12

1. Parotid: serous (watery)
2. Submandibular: serous>mucus
3. Sublingual: mucus

Question 13

Describe pharyngeal reflex (swallowing reflex pt 1)

Answer 13

1. swallowing centre in MO
2. soft palate elevates
3. upper oesophageal sphincter relaxes
4. elevated pharynx opens oesophagus
5. bolus pushed into oesophagus by pharyngeal constrictors
6. epiglottis tips to cover larynx and larynx is elevated to prevent bolus going down it

Question 14

Describe the esophageal reflex (swallowing reflex pt 2)

Answer 14

stretch of esophagus causes enteric NS to initiate perastalsis in muscles of esophagus

Question 15

Describe the gastro-ileal reflex

Answer 15

when stomach is full, garstin (hormones) => release of ileocaecal valve => SI empties

Question 16

Describe the gastro-colic reflex

Answer 16

chyme in stomach initiates mass movements of contents in transverse colon to move into rectum

Question 17

Describe the duodeno-colic reflex

Answer 17

chyme in duodenum initiates mass movementsof contents in transverse colon to rectum

Question 18

Describe the mastification reflex

Answer 18

descending pathways from cerebrum => conscious control when chewing

Question 19

Define haustral churning/contractions (haustrations)

Answer 19

segmentation integrated by local reflexes (intrinsic/enteric plexus)

Question 20

Define Mass movements (in large intestine)

Answer 20

Peristaltic waves initiated by gastro-colic & duodeno-colic reflex and integrated by enteric plexus