Distal GIT I

Question 1

Basic Structural Organisation of GIT tubes

Answer 1

1, mucosa (epigenetic, lamina propria, mscularis mucosal)

2. sub mucosa
3. muscularis external
4. serosa

Question 2

difference bw oesophagus and aorta and trachea

Answer 2

• O= Anterior to aorta (a= thicker, beige, vasa vasorum, o=pink, made of muscle) + O= Posterior to trachea (trachelus connective tiss merges with adventia layer of o)

Question 3

positions of recurrent laryngeal, vagus and oespho

Answer 3

o Recurrent lar= sitting in tracheo os groove
o Vagus= moves down with common carotid, recurrent lar branches off, while vagus laps around oesophagus, becomes oesphageal plexis and gets into abdomen
• // vagus supplies para, thoracic-spanchnic = symp

Question 4

describe structure of outer muscle

Answer 4

o Inner circular muscle= helps squeeze food

o Outer longitudinal muscle= helps propel down

Question 5

describe thirds of oesphogaus

Answer 5

• Proximal 1/3 striated muscle (voluntarily via vagus), middle 1/3 mixed (blending smooth= nuclei centrally long + spindly, skeletal= peripheral many nuclei), distal 1/3 smooth

Question 6

describe mucosa of oesphagus

Answer 6

• Squamous strat
o Layers= protection of blood vessels
• Connective tissue of lamina prop
o Dense irregular

Question 7

what is located in between two layers of muscular extern

Answer 7

arteirole

myenteric nerve plexus

Question 8

• Musc externa vs musc mucose

Answer 8

o = rounder // cut axil

o Mucosa= longitudinal plane

Question 9

what is smooth muscle of oesophagus innervated by

Answer 9

vagus nerve

Question 10

where are acini in the oesophagus and what are they

Answer 10

• Sub mucosa= Mucus acini
o Peripheral nuclei
o Lubrication

Question 11

what is the cardioOesophageal Junction

Answer 11

z line- Harsh transition of mucosa (b/w strat sqamous vs tall columnar mucus secreting cells)
left of t11

Question 12

why the need for z line

Answer 12

Alterative functions of stomach vs oesophagus
• Stomach breakdown // requires enzymes, muscle layers, acidic
o Needs mucus secreting to protect stomach lining
o Stomach= simple columnar
• Oesophagus movement
o // stratified

Question 13

blood supply of stomach

Answer 13

o Left gastric artery (from celiac trunk)

Question 14

what are the 3 orientations of smooth muscle of the stomach

Answer 14

inner oblique, inner ocular, outer longitudinal

Question 15

what is the sentosa of the stomach

Answer 15

visceral peritoneum

Question 16

4 stomach cell types

Answer 16

surface mucus (alkaline + mucin)
mucus neck (acidic fluid + mucus)
parietal cells= intrsinc factor and HCL)
Chief  cells= pepsinogen + gastric lipase

Question 17

diff b/w parietal and chief cells

Answer 17

parietal= esonifilic city, central nucleus (fried egg)
Cheif= granular city, basally located nucleus