L1: Intro to GIT Physiology

Question 1

What are each of these layers of the GIT

Answer 1

Question 2

Answer 2

Question 3

Outmost layer when tissue is outside the peritoneum (e.g. upper Oesophagus)?

Answer 3

Adventitia

Loose Connective Tissue

Question 4

Outmost layer when tissue is within the peritoneal cavity (e.g. Stomach)

Answer 4

Serosa

lubrication function

Question 5

Innervation of the GIT?

Answer 5

EXTRINSIC (Autonomic nervous system)

• Sympathetic Nervous System
• Parasympathetic Nervous system

INTRINSIC (Enteric Nervous System)

• Myenteric Nerve Plexus (Auberbach’s Plexus)
• Submucosal Nerve Plexus (Meissner’s Plexus)

Question 6

Location/Role of Meissner’s Plexus?

Also known as?

Answer 6

Located in Submucosa (Regulates Secretion/Blood Flow)

Submucosal Plexus

Question 7

Location/Role of Auerbach’s Plexus?

Also known as?

Answer 7

Located in Muscularis externa. Between longitudinal and circular layers!! (Regulates Motility)

Question 8

Distance of Ganglia from Target
(Sympathetic vs. Parasympathetic)

Answer 8

Question 9

Differing roles of Submucosal Plexus and Myenteric Plexus?

Answer 9

Submucosal = Meissner’s

Myenteric = Auerbach’s

Question 10

Sphincter muscles receive basal tone from ________ fibers

Answer 10

Sympathetic FIbers

Synmpathetic Innervation maintains continence

Question 11

Salivary Glands are under what kind of control?

Answer 11

Neural

Question 12

Stomach is under what kind of control?

Answer 12

Neural and Hormonal

Question 13

Pancreas is under what kind of control?

Answer 13

Neural and Hormonal

Question 14

Parasympathetic vs. Sympathetic Nervous System in Digestion?

Answer 14

Parasympathetic Nervous System in Digestion:

• Secretory Cells: Chrolinergic, M1 (Gastric Acid), M3
• Motility: Stimulatory (M1/M3) (Long/Short Reflexes)

Sympathetic Nervous System in Digestion:

• Secretory Cells: Alpha Adrenoreceptors (Vasoconstriction)
• Motility: Inhibitory (Sphincters are exception (maintains continence))