Quiz 4 Flashcards
____ molecules can pass through capillary walls while _____ cannot.
1) Nonpolar (O2, CO2, lipid soluble things)
2) Plasma proteins
What is bulk flow?
Movement of water soluble substances (ions, glucose, a.as) through pores/intercellular clefts.
True or false… The lymph system carries stuff from the interstitial fluid to the venous system in either direction.
FALSE. The lymph system only moves things in one direction, towards the venous system.
True or false… The fluid that is not picked up by the venous system in a capillary bed is called lymph.
FALSE. It is interstitial fluid. It is called lymph once it is in the lymphatic system
What is the direction of the colloid osmotic pressure? What causes this force?
Plasma proteins (namely albumin) PULLS fluid from the interstitial fluid into the circulatory system. Note that osmotic pressure from the interstitial proteins also exists, however it is a nearly negligible force.
Blood velocity is ____ in arteries and ____ in capillaries.
1) Fast
2) Slow
Which direction does hydrostatic pressure go?
PUSHES out.
Where do we see the largest hydrostatic pressure drop?
In the arterioles
What is the role of a precapillary sphincter?
It’s a cuff of smooth muscle that surrounds each true capillary (right off of the metarteriole). It helps regulate blood flow. If these sphincter a close, the blood may bypass the capillary bed (vascular shunt)
True or false… The translocation of macromolecules across the capillary membranes requires ATP.
TRUE
Which are thicker, blood capillaries or lymphatic capillaries?
Lymphatic capillaries. These also have a lower pressure
Name 4 potential causes for edema
1) increased capillary blood pressure (increased plasma volume, increased venous pressure)
2) Decreased plasma colloid osmotic pressure (less albumin)
3) increased capillary permeability
4) obstruction in lymphatic system
Which layer of the GI tract contains large vessels and nerve plexuses
Submucosa
Do retroperitoneal organs have serosa or adventitia?
BOTH. They have adventitia where attached to another organ and serosa everywhere else
Smooth muscle in the GI tract has a ____ inner layer and a ____ outer layer
1) circular
2) longitudinal
What layer(s) does the pharynx lack?
Muscularis mucosa of mucosa layer and SUBMUCOSA
When the bolus passes the pharynx into the esophogus, does the trachealis muscle relax or contract?
Relax
What is the difference between serosa and adventitia?
both are connective tissue linings… However the serosa is also covered in MESOTHELIUM
The upper 1/3 of the esophogus is _____ muscle while the lower 1/3 of the esophogus is ____ muscle
1) skeletal
2) smooth
Describe the lower esophageal sphincter.
It is not anatomically distinct. It is made up of a thickening of the muscularis external. When it relaxes, it allows the passage of the bolus
What type of tissue is found in the esophagus and stomach?
Stratified squamous in esophagus. Simple columnar in stomach.
Explain the differences in the pits/glands in the different regions of the stomach.
Cardia: short pits, long glands
Body/fundus: relatively long glands
Pylorus: long pits, short glands.
Chief cells secrete…
Pepsin and lipase
Parietal cells secrete (2 things)…
HCl and intrinsic factor
Where are the stem cells located in the GI tract?
At the top of glands (at the bottom of pits)
G cells secrete ____ which functions to…
Gastrin. This functions to stimulate the parital cells to secrete acid.
Describe the differences between surface mucus cells and mucous neck cells.
Obviously the surface mucus cells are on the surface… But also…
Surface mucous cells are more columnar, secrete bicarbonate to diffuse the acid.
Mucous neck cells are rounder, less numerous, and have apical granules
What does gastric intrinsic factor do?
Aids in the absorption of vitamin B12
G cells secrete ____, ____, and _____ from the _____ part of the cell into the _____. _____
1) Gastrin/histamine
2) Ghrelin (satiation)
3) serotonin
4) basal
5) blood
6) 🤓
Explain the cephalic phase
It’s responsible for 30% of HCl secretion. Stimulated by smell, taste, conditioning.
Strictly due to vagus nerve
Describe the gastric phase
60% of HCl secretion.
Stimuli are DISTENSION, amino acids, and small peptides.
Due to vagus nerve and Gastrin and local reflexes.
True or false… Fats are absorbed into the lymphatic system instead of blood.
True
What do Microfold (M) cells do?
They are located over peyer’s patches (so they are in the ileum). They endocytose antigens and dump them into the peyer’s patches (where lymphocytes and dendritic cells reside)
What are Enterocytes?
What are Paneth Cells?
What are Enteroendocrine Cells?
1) columnar cells that absorb water
2) secrete anti microbial molecules (lysozyme, defining, phospholipase A) (also are progenitor cells) located at the bottom of crypts
3) Local and systemic signals relating to digestion
In the stomach, the chemical digestion of what begins?
Lipids (by lipases)
Proteins (by pepsin)
Although carbohydrate digestion occurs, carb digestion begins in mouth
Explain the absorption of lipids
1) Bile EMULSIFIES lipids into micelles.
2) gastric lipase digests the lipids into FAs and glycerol
3) diffuse into cells
4) resynthesized in the SER
5) pass through the RER to the Golgi where they are packaged into CHYLOMICRONS
6) enter the lymphatic circulation, thus bypassing the liver
How are amino acids and carbohydrates absorbed?
Through active co-transport with sodium. (Fructose freely diffuses.. For whatever reason)
What things do the Enteroendocrine cells secrete and what do they do? (4 things)
Secretin: stimulates bicarbonate and water secretion of pancreas and bile ducts, inhibits secretion of H+ by parietal cells of stomach. (This neurualizes pH in duodenum
Cholecystokinin: signals immediate satiety to brain. Also causes contraction of gall bladder.
Gastri inhibitory peptide: stimulates insulin secretion by B cells in pancreas
Peptide YY: signals long term satiety.
What is the myenteric plexus?
Collection of symp. And parasympathetic nerves that regulate GI function and sense distension
Describe the mucosa of the large intestine
No Villi
Tubular columnar intestinal glands (so no pits?)
Goblet and absorptive cells
Name the five types of common biochemical reactions. Which is the way electrons are transferred in a biological system?
1) making/breaking carbon bonds
2) molecular re-arrangements
3) free radical reactions
4) group transfers
5) REDOX reactions
Redox is most common in bio systems
Name 5 common group transfers and the enzymes that accomplish them.
Phosphorylation - Kinase Ubiquitination- ubiquitin ligase Acetylation - acetyltransferase Methylation - methyltransferase Hydroxylation- hydroxylase
ATP can provide free energy via two different methods. What are these methods?
Group transfer and hydrolysis of itself (magnesium stabilizes this and allows it to occur)
As the concentration of ATP increases, the amount of energy released per ATP increases. True or false?
True