3/5- Capillaries (Exam 2) Flashcards
What is vasomotion?
Blood flow in capillaries are start/ stop
What are precapillary sphincters?
Muscular door (open and close)
Open door for blood to pass through capillaries
Closed door and blood is directed away
Responds to chemical signals from cells living around the capillary
Open and/ or close door depending on happy or bad signals
What is a thoroughfare channel?
Run down center of capillary bed
Straight line between arteriole and venules
There are no back ups in the arteriole
Why is there blood supply to the cells?
To bring nutrients and oxygen and to take away CO2
What are 2 different kinds of capillaries?
1) continuous capillaries
2) fenestrated capillaries
What is a continuous capillary?
Most common
Epithelium forms continuous lining (simple squamous epithelium)
Materials enter or exit through squeezing or diffusing through cells
What are fenestrated capillaries?
Permeable
Things go through cell easily
Window like pores built into vessel
In kidney
What are 3 processes happening simultaneously in capillaries for movement?
1) diffusion
2) filtration
3) osmosis
What is diffusion is a capillary?
High concentration to low concentration moving down its concentration gradient until equilibrium
What is urea?
Primary waste product that’s toxic
What is capillary filtration?
Using hydrostatic force
Separating material based on size
Small things go through
What is hydrostatic force?
Pressure generated by trapped force
Liquid under pressure
What is the capillary hydrostatic force?
Blood pressure over interstitial fluid
Blood pressure in vessel
What is interstitial hydrostatic pressure?
Blood pressure below interstitial fluid
Pressure exerted by interstitial fluid
What happens with water and material dissolved in it?
Pushed out of vessel by hydrostatic pressure
Then force is greater outside vessel than inside
So the water goes back into the vessel with waste instead of nutrients
What are plasma proteins?
Liquid portion of the blood with lots of proteins
Proteins are too big to get through holes of cells
Remains in the blood from one side to the other
What is osmosis?
Blood goes through capillary it becomes more concentrated because water was pushed out (more water outside vessel than tissue) water goes back to vessel
Water going down it’s concentration gradient through a semi permeable membrane
Endothelium is the semi permeable membrane
Generated force of osmotic pressure
What happens to the proteins?
Too small to settle to the bottom of the liquid because of gravity
What is the colloid osmotic pressure?
Pressure of osmosis
Blood becomes a colloid because the proteins don’t settle to the bottom
What is the wanna be capillary and explain why
Sinusoids
There is and then there isn’t a wall
Where blood bathed in tissue
Found in lobules of liver
