Unit 3 red topics

Three cell types in the alveolar wall are?

type I cells which is 97% of surface and provides gas exchange

type II alveolar cell produces pulmonary surfactant to reduce surface tension

alveolar macrophage is immune cell to remove debris and pathogens

pulmonary ventilation has two steps and what muscle groups? and what happens to the thoracic cavity

inhalation and expiration

diaphragm and intercostal muscles of the rib cage

they increase the volume of the thoracic cavity and decrease the pressure in the lung relative to the atmospheric pressure

What is quiet breathing?

occurs at rest and is autonomic.

external respiration

exchange of gases with the environment and occurs in the alveoli

move by simple diffusion down pressure gradients and no energy required

internal respiration

exchange of gases from blood to cells

occurs at tissues or cells

simple diffusion

How is oxygen transported?

through the use of hemoglobin in RBCS

Oxygen saturation is affected by what?

pH, pressure and temperature

Carbon dioxide is transported in 3 ways?

blood plasma- 7-10% of CO2

bicarbonate- 70% of CO2 in blood. Co2 is converted into HCO3 through the action of carbonic anhydrase

RBCs- 20% CO2 transported as carbominohemoglobin in the RBCS, bound to hemoglobin and falls down partial pressure gradients

What are the primary functions of the digestive system?

break down ingested food and absorb nutrients released

What are the layers of the alimentary canal?

mucosa- interspersed with goblet cells and enteroendocrine cells

lamina propria

muscularis mucosae

submucosa- blood and lymphatic vessels and submucosal glands that release digestive enzymes

muscularis- creates greater surface area for contact with food

serosa-

Peritoneum

broad serous membrane surrounding the digestive system

holds it to teh abdominal wall and protects the organs of the GI

what are the five folds of the peritoneum?

greater omentum- apron-like structure superficial to small intestine

falciform ligament- anchors the liver

lesser omentum- provides pathway for structures connecting to liver

mesentery- anchors all small intestine

mesocolon- attaches two portions of large intestine to posterior abdominal wall

enamel

surrounds dentin in crown and strongest part of body

what does the epiglottis do when swallowing?

folds over the glottis preventing food going down the wrong tube

what is the pyloric sphincter?

before the duodenum and controls food going into the small intestine

rugae

folds of the stomach to allow for expansion

Parietal cells

produce HCL and intrinsic factor needed for B12 absorption

essential for life

chief cells

secrete pepsinogen and proenzyme form pepsin

What are the three phases of gastric secretion?

cephalic-mental, may occur absent of food but with the thought or smell of food

gastric - triggered by food in stomach and lasts 3-4 hours

intestinal - triggered by food in the duodenum, stimulates gastrin and closes pyloric sphincter

What is the only function of the stomach absolutely essential for life?

intrinsic factor

Circular folds of small intestines

cause chyme to spiral, extending time in the lumen

Vili

increases surface area

blood absorption

microvilli

secretes enzymes

intestinal glands

secrete intestinal juices

function of large instestine

absorb water and nutrients

vitamin synthesis

form and eliminate feces

haustra of large intestine

pouches that make the large intestine appear wrinkled

epiploic appendages

attached to teniae coli

are fat filled sacs of unknown purpose

accessory organs are

liver

gallbladder

pancreas

liver

bile is secreted by the liver to emulsify fats into smaller globules so they can be digested. contains bile salts and phospholipids

gall bladder

stores and release bile through common bile duct into the duodenum