L.1

Question 1

Digestive system is made up of:

Answer 1

1.Gastrointestinal tract (GIT)
2.The accessory organs that help the digestion.

Question 2

Gastrointestinal tract :

Answer 2

1. Mouth , Pharynx.
2. Esophagus, Stomach.
3. Small intestine.
4. Large intestine.

Question 3

Accessory organs of digestive system:

Answer 3

1) Teeth.
2) Tongue.
3) Salivary glands.
4) Exocrine part of pancreas.
5) Liver.
6) Gall bladder.

Question 4

The function of the alimentary tract is to provide the body with :

Answer 4

water
electrolytes
vitamins
nutrients.

Question 5

Functions of the digestive system require:

Answer 5

(1) “Movement” of food through the alimentary tract.
(2) “Secretion” of digestive juices and digestion of the food.
(3) “Absorption “of water, electrolytes, vitamins, and digestive products.

Question 6

Control of all digestive system functions by :

Answer 6

nervous and hormonal systems.

Question 7

GIT wall is formed by “four layers” which are from “inside to out” :

Answer 7

1) Mucosa.
2) Submucosa.
3) Muscle layer.
4) Serosa.

Question 8

Epithelial cells of mucosa is concerned with:

Answer 8

a) Secretion of digestive juices & GIT hormones.
b) Absorption of the digested diet (Food).

Question 9

The muscle layer formed of :

Answer 9

(circular & longitudinal).

Question 10

Circular muscle :

Answer 10

Its contraction —> decrease in diameter of GIT lumen

“يضيق”

Question 11

Longitudinal muscle :

Answer 11

Its contraction —> “shortening” of GIT

Question 12

(Nervous Control of GIT functions )

Motor & secretory functions of GIT are controlled by :

Answer 12

1) “Intrinsic” innervation (Enteric nervous system).
2) “Extrinsic “innervation (Sympathetic and parasympathetic).
3) “Nervous” regulation of GIT through GIT reflexes.

Question 13

Intrinsic innervation consists of :

Answer 13

• submucosal plexuses
• myenteric (Auerbach’s) plexuses.

Question 14

Sub-mucosal plexus:

Answer 14

Site: In the submucosa.
Function: Controls secretion & blood flow

Question 15

Myenteric plexus :

Answer 15

Site: Between the two muscle layers.

Function: Controls “motility” of GIT.

Question 16

Enteric nervous system (E.N.S) is considered as the :

Answer 16

second brain or gut brain

Question 17

All classes of (chemical transmitters) in brain are found in

Answer 17

enteric nervous system

Question 18

enteric nervous system controls ?

Answer 18

• most functions of the GIT

• function (independently)
even without sympathetic or parasympathetic stimulation

• BUT parasympathetic & sympathetic Stimulation can greatly stimulate or inhibit GIT

Question 19

Extrinsic innervation The GIT receives nerve supply from:

Answer 19

▪ sympathetic & parasympathetic systems

▪ These fibers “end on “the nerve cells of E.N.S. , controlling their activity.

Question 20

(Sympathetic)

Carrying nerves:

Answer 20

Carrying nerves:

1.Greater splanchnic nerve
(to abdominal viscera)

2. Lesser splanchnic nerve
   ( to pelvic viscera).

Question 21

(sympathetic)

Function :

Answer 21

. Inhibitory to most GIT functions

. Inhibits motility & secretion

. Closes sphincters —> (-) evacuation

Question 22

(Sympathetic)

Chemical transmitter:

Answer 22

Noradrenaline

Question 23

(Parasympathetic)

Carrying nerves :

Answer 23

1.Vagus nerve

2. pelvic nerve

Question 24

(Parasympathetic)

Function :

Answer 24

• “Excitatory” to most GIT functions

• Stimulates motility & secretion

• Opens sphincters —> (+) evacuation

Question 25

Functions of chemical transmitters of parasympathetic system : • Acetylcholine : دا الاساسي

Answer 25

Increases motility and secretions of GIT.

Question 26

Functions of chemical transmitters of parasympathetic system : • Vasoactive intestinal polypeptide (VIP) :

Answer 26

Helps relaxation of GIT sphincters

Question 27

Functions of chemical transmitters of parasympathetic system : • Gastrin-releasing peptide(GRP):

Answer 27

Stimulate gastrin release from G cells of stomach

Question 28

(Nervous regulation of GIT through GIT reflexes) divided into 3 types according to the center of the reflex :

Answer 28

1- Local enteric reflex 2. Ganglionic reflex 3.Central reflex

Question 29

Local enteric reflexes: معلومة من الدكتورة “Center in wall of GIT”

Answer 29

• These reflexes are "integrated" entirely in the "enteric nervous system" . E.g. : gastrin secretion, peristalsis. مهمة الامثلة

Question 30

Ganglionic reflexes: معلومة من الدكتورة "Center in ganglia "

Answer 30

• These are integrated at collateral sympathetic ganglia • Ganglia act here as nerve centers. •e.g. : gastrocolic reflex

Question 31

Central reflexes: معلومة من الدكتورة ‏"Center in CNS "

Answer 31

• These reflexes are "integrated in the CNS" (the brain stem & spinal cord). • e.g. : spinal defecation reflexes.