GI!!!!!! yay

Question 1

how long is GI tract?

Answer 1

4.5 m

Question 2

accessory glands and organs

Answer 2

salivary glands
liver
gallbladder
pancreas

Question 3

how are sphincters constricted

Answer 3

tonically

Question 4

4 tissue layers of GU (inside to outside)

Answer 4

mucosa
submucosa
muscularis externa
serosa

Question 5

mucosa

Answer 5

=innermost layer

1. epithelium= single layer of epithelial cells. transporting cells, secretory cells, stem cells
2. lamina propria= loose connective tissue. contains glands, lymph vessels, blood supply, nerve fibers
3. muscularis mucosae= “fence”

Question 6

submucosa

Answer 6

made of:
loose connective tissue
contains nerve trunks, blood supply and lymph vessels

the intestine has a submucosal plexus (part of the enteric nervous system)

Question 7

muscularis externa

Answer 7

has 2 layers of smooth muscle

1. inner circular layers (constricts lumen)
2. outer longitudinal layers (shorten tract)

myenteric plexus (another part of ENT) is located between the two muscle layers

Question 8

Serosa

Answer 8

outer covering of the entire GI tract, continuous with the peritoneal membrane that lines the abdominal cavity

made of secretory epithelium and connective tissue layers
- lubricates, protects and suspends

Question 9

peristaltic contractions

Answer 9

propel contents forward

circular muscles contract just behind the bolus to push it forward

Question 10

segmental contractions

Answer 10

mixing contents to break up food and increase exposure to enzymes
etc.

short segments of intestine contract and relax alternately

Question 11

what does the GI system secrete?

Answer 11

Na+, K+, Cl-, HCO3-, H+ and water follows by osmosis

digestive enzymes

mucus

bile etc.

Question 12

the enteric nervous system

Answer 12

the brain in the gut

regulates motility and secretions throughout the GI tract. modulated by the autonomic nervous system