What are Astrocytes, Ependymal cells, Oligodendrocytes, Microglia classifed as, where are they located?
Glial cells, central nervous system
What are microglia and where are they located?
Immune cells in the central nervous system
Which cells serve as immune system cells in the central nervous system?
What is the name of the valve connecting the atrium and the ventricle?
Atrioventricular valve (AV valve)
In a myocardial pumping cell, which channels open and close during depolarization?
V-gated Na channels open (letting in Na to depolarize) and V-gated leaky K channels close.
In a myocardial pumping cell, V-gated leaky K channels are open, while V-gated Na channels and L-type Ca channels are closed. What state is the cell in? What is the membrane potential?
The cell is at rest (repolarization has occured). Membrane potential is close to -90 mV.
In a myocardial pumping cell, V-gated leaky K channels are closed, while V-gated Na channels are open and L-type Ca channels are closed. What state is the cell in? What is the membrane potential?
The cell is depolarizing, at the beginning of an action potential. The membrane potential quickly depolarizes to 0 or higher.
In a myocardial pumping cell, V-gated leaky K channels are closed, while V-gated Na channels are closed and L-type Ca channels are open. What state is the cell in? What is the membrane potential?
The cell is in the plateau phase of depolarization. The membrane potential is close to 0, dropping slowly.
What is the first step in a depolarization of an autorhythmic cardiac cell?
The "downswing" in membrane potential causes funny-type Na channels to open
What causes funny-type Na+ channels in an autorhythmic cardiac cell to open and close?
A negative (polarized) membrane potential causes F-type Na+ channels to open, causing the cell to depolarize. That depolarization (membrane potential nearing zero) then causes F-type Na+ channels to close.
In an autorhythmic cardiac cell, what is the purpose of Transient(T)-type Ca++ channels and when do they open?
T-type Ca++ channels open at the beginning of depolarization (caused by F-type Na channels) and continue the depolarization to threshold.
In an autorhythmic cardiac cell, what is the purpose of (L)-type Ca++ channels and when do they open?
L(long)-type Ca++ channels open when the cell reaches threshold membrane potential, and stay open for a time to continue depolarizing.
In an autorhythmic cardiac cell, what is the purpose of Voltage-gated K+ channels and when do they open?
The VG K+ channels open at the end of depolarization to re-polarize the cell.
Name all the ion channels involved in cardiac pacemaker potentials in an autorhythmic cardiac cell.
F-type Na+ (open when polarized, close when polarized)
T-type VG Ca++ (open when depolarized, continue depolarization to threshold)
L-type VG Ca++ (open when threshold is reached, delays repolarization)
VG K+ (open to re-polarize the cell)
What effect does digitalis have on the heart?
Increases strength of heart contractions, increasing ejection volume.
How do you calculate hematocrit?
hematocrit = RBC count
Erythrocyte volume / Total blood volume
After a hemorrhage, what mechanism does the body use to help return the blood volume to normal?
Autotransfusion - lowered hydrostatic pressure in the capillaries (Pc) results in increased absorption of fluid from the interstitium, adding to the plasma volume.
After a hemorrhage, how does the body adjust these factors? (reflex compensations) Which of these are attempting to return to normal?
1. Stroke volume
2. Heart rate
3. Cardiac Output
1. Increased (to return to normal)
3. Increased (to return to normal)
5. Increased (to return to normal)
How is cardiac output (CO) calculated?
Stroke volume x Heart rate
How is Mean Arterial Pressure calculated?
Cardiac Output x TPR
What hormone stimulates creation of red blood cells?
What is the purpose of the hormone erythropoitin?
stimulate production of red blood cells
During aerobic exercise, how are the following factors changed?
2. diastolic/systolic pressure
3. Cardiac output
4. P(CO2) in systemic arterial blood
5. pH in systemic arterial blood
6. Mean Arterial Pressure (MAP)
1. Decreases (in muscles and heart)
2. Stays the same/increases
3. Increases (increases in heart rate and stroke volume)
4. Stays the same
6. Increases (increase in CO is greater than decrease in TPR)
What is hypovolemic shock? How is it treated?
Blood volume/fluid volume is too low - give the patient fluids