Chapter 14 general questions Flashcards
Cardiovascular system: moves blood from veins to arteries (blood vessels that carry oxygen-poor blood to your heart)
- closed-loop
- The right side pumps blood to the lungs
- The left pumps blood everywhere else
- The right heart is fairly low-pressure bc it doesn’t have to go very far to go through the lungs & too much pressure will cause problems in the lungs
- The left heart produces a lot of pressure bc it has to push blood all the way through body
What is the difference between deoxygenated and oxygenated blood?
The blood that has a higher concentration of oxygen is known as oxygenated blood.
The blood that has a higher concentration of carbon dioxide is known as deoxygenated blood.
The deoxygenated blood flows through the veins.
The oxygenated blood flows away from the heart.
Why is vasoconstriction / dilation such a big deal?
can change the flow a lot by contracting smooth muscle and altering the radius of the blood vessel
Trip 1:
Lungs right heart
Pressure gradient in systemic circulation
the heart is a pump which will generate pressure
- the first big artery coming out of the heart is the aorta which branches into the artery that carries blood to the kidney.
- the exchange happens in capillarities, delivering oxygen to the tissues & taking waste products and CO2 away.
- vena cavae brings blood back to the heart
flow will happen in:
-flow will happen from higher pressure to an area of lower pressure
- low pressure in veins
Fluid requires a pressure gradient
higher pressure —— flow —-> lower pressure
how much flow? 100 mmHg to 100 mmHg? None there’s no pressure difference so blood will just sit there.
Flow and pressure gradient
flow:
100 mm Hg ——> 75 mm Hg
40 mm Hg ——–> 15 mm Hg
The highest flow: flow is equal to 25 mm Hg difference. Depends on the change in pressure
The bigger the pressure difference, the stronger the flow
big hose and small –> more flow in a big hose compared to small hose
The bigger the resistance the less ______ you have
flow
- a little hose has a higher resistance than a big hose you will have more flow going through a big small than a small hose.
r is raised to 4, any change you make in the radius is going to be raised to the 4th power
flow is 16 times higher if you double the diameter of the tube
Two kinds of myocardial cells
contractile cells (generate power stroke of the heart). contract when told to
autorhythmic cells: generate rhythm
SA node:
main pacemaker of the heart and it will generate rhythmic action potential and set the pace
contractile cells
think about how they are different from skeletal:
smaller, in the skeletal muscle all of those muscle cells are assembled into one cell. They fuse and muscle cell goes all the way from one tendon to another tendon.
Cardiac contractile cells are smaller and have a single nucleus and they tend to branch. Instead of being fused like skeletal muscle fibers to make one big cell they keep their identity but are connected by intercalated disks (hold the cells together, they have gap junction so electrical activity can pass from one cell to the next).
They hold together bc they have desmosomes when they contract they stay together.
Both have
both striated
t-tubules are larger and branch
sarcoplasmic reticulum is smaller
Cardiac muscle (excitation-contraction coupling and relaxation in cardiac muscle)
- you get an AP in the membrane —> opens voltage-gated ca+ channels
2
Trip 2:
Systemic left heart
what does veins and arteries do to the heart?
Veins bring blood to your heart.
Arteries take blood away from your heart.
Which of the following would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume.
* cardiac output = heart rate x stroke volume.
Which of the following would increase heart rate?
epinephrine (Adrenaline makes your heart beat faster and your lungs breathe more efficiently. It causes the blood vessels to send more blood to the brain and muscles, increases your blood pressure, makes your brain more alert, and raises sugar levels in the blood to give you energy. Your pupils grow larger and you sweat.)
norepinephrine (norepinephrine increases heart rate and blood pumping from the heart)
both play a role in your body’s natural fight-flight response to stress
How would an increase in the sympathetic nervous system increase stroke volume?
increased contractility.
- by increasing available calcium), thus increasing stroke volume. Contractility causes an increase in stroke volume by decreasing end systolic volume; it does not change end diastolic volume.
By what mechanism would an increase in venous return increase stroke volume?
increased end diastolic volume.
- an increase in venous return increases the end diastolic volume. The fibers are stretched more, resulting in an increase in the force of contraction (preload, or the Frank-Starling Mechanism).
How would a decrease in blood volume affect both stroke volume and cardiac output?
decreased stroke volume and no change in cardiac output.
- ecreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in an effort to maintain cardiac output.
Which of these is the best definition of an artery?
A vessel that carries blood away from the heart
Most of the oxygen exiting the blood and entering the tissues does so from the ________.
capillaries
Arteries are most accurately defined as blood vessels that ________.
carry blood away from the heart
