Review ch23 Flashcards
(36 cards)
Process of digestion
ingestion, propulsion, mechanical breakdown, digestion, absorption, defecation
What is segmentation?
a part of mechanical breakdown in the small intestine. contractions and mixing of juices and food to help absorb
What is mesentery? what are its 3 functions?
double layer of peritoneum fused back to back. extends from the body wall to the digestive organs
F: store fat, hold organs in place, provide routes for BV, Lymphatics, nerves
What organs are in the retroperitoneum?
pancreas, duodenum, large intestine
Peristalsis is part of which process?
propulsion
4 basic layers of the alimentary canal
mucosa, submucosa, muscularis externa, serosa
What are the 3 sublayers of the mucosa? Explain all 3
- epithelium- simple columnar EXCEPT in esophagus, mouth, anus - stratified squamous and mucus-secreting (enzyme secreting)
- lamina propria- loose areolar c.t. - rich supply of capillaries for nourishment and absorption. Has MALT
- muscularis mucosae- smooth muscle, produces local mvmts to enhance secretion/absorption
What is the submucosa layer made of? Function?
- aerolar connective.t
- has lymphoid follicles, nerve fibers, rich blood supply.
- lots of elastic fibers allow it to change shape and regain normal shape (Stomach)
Which layer is responsible for peristalsis and segementation?
muscularis externa
Muscularis externa has inner layer and outer layer explain both (also forms sphincters)
inner= circular outer = longitudinal
How is the serosa membrane (visceral peritoneum) formed?
from areolar connective.t with mesothelium - which is a single layer of squamous ep cells
The esophagus has a dense connective tissue layer - instead of the serosa - what is this layer called?
Adventitia
T or F
Reteroperitoneal organs have both adventitia and serosa?
TRUE
The enteric nervous system has 2 plexuses, name and explain
Submucosal nerve plexus- regulates glands and is in the submucosa
Myenteric nerve.p- in muscularis mucosae - control GI motility
What are the 3 key concepts in the regulation of digestive activities?
- digestive activity is triggered by many mechanical and chemical stimuli - certain foods that change pH, osmolarity, stretch
- effectors of digestive activity are smooth muscle and glands
- neurons (intrinsic/ex) and hormones control digestive activity
Salivary glands secrete 2 types of cells - mucous and serous- what do these cells produce?
Mucous- mucus
Serous- watery secretion that has enzymes , ions and some mucin
Salivary glands have what types of enzymes?
amylase, lingual lipase (fat)
What 3 protective factors of saliva?
- Defensins - act as local antibiotics, function as cytokines to call other defensive cells
- lysozyme- the bacterial enzyme that inhibits bacteria growth. can help with tooth decay
- IgA antibodies
What is the muscularis externa made of in the esophagus?
Superior is skeletal muscle and inferior is smooth muscle
what part of the pharynx allows for food to move down?
contractions of the pharyngeal constrictor muscles - Longitudinal layer
main function of esophagus and pharynx?
Propulsion of food
Swallowing (deglutition) has 2 phases explain
- Buccal phase- in mouth and is voluntary
2. pharyngeal-esophagus - involuntary, involves vagus nerve
Which part starts the chemical breakdown of proteins? How?
Stomach - parital cells secrete HCL which converts pepsionogen to pepsin (active enzyme)
Longitudinal folds in stomach, stores mucosa
Rugae
