Chapter 9 + in class notes

What is the only artery that doesn’t carry oxygenated blood?

pulmonary artery

What are the upper chambers of the heart called?

Atria

Ventricles

Lowe chambers of the heart

How many chambers in the heart?

4

Do the atrium and ventricles contract at the same time?

Yes

Describe blood flow through heart to lungs

superior vena cava to right atrium, right atrioventricular valve opens, right ventricle, out of pulmonary arteries to lungs

Why do we need less pressure lower when going to the lungs.

Why is the left ventricular wall thicker than the right?

This is where pressure is generated and at its highest

What happens if there’s an occlusion? What happens to the pulmonary artery

pulmonary artery develops more pressure to compensate.

What are the two type of cardiac cells?

Cardiumyocytes (majority) and ___ (minority)

What dictates strength of contraction?

gradient of calcium

Coronaries

Blood flow to the heart. Happens in diastolic when heart relaxes

What are the three important ion movements of pacemaker potential?

In Na, In Ca, Out K

How to increase strength in heart

Membrane and calcium clock

What is the membrane clock

changes in the permeability of the surface membrane ion channels

Does permeability to calcium change

Yes

Action potential in cardiac cells

Has resting membrane potential of -90 to match K. Threshold potential at -70

What causes the peak in cardiac AP

Opening of Na Pumps and Na into the cell

Why do we want calcium to slowly come in during plateau

Uniform contraction, prevent tetanus of the heart

What ion controls majorly the plateu phase of AP

calcium

How do you start the contraction in contractile cells (starting AP)

Na (sodium)

How do the L-type channels differ from the other channels in autorhythmic vs contractile cells

Compare L-type and T-type channels

Why does the heart not have summation/shorter refractory period

Do not want risk of tetanus. Peak tension of heart has a little bit of a delay. Shortening of the refractory period is bad.

What causes the refractory period in cardiac?

The period of inactivation of sodium channels accounts for this duration. So, it doesnt fire another AP again before one is done

Where in the heart does the first AP occur

Sinoatrial node

Where does the sinoatrial node send the impulse to?

Interarterial pathway and internodal pathway

Where does the internodal pathway lead?

atrioventricular node

Where does AV node lead

down the bundle of His to the Purkinje fibers

Where is the blood filled first

atrium

Explain the timing of impulse through the heart

SA node fires AP, AV node delays, bundle of His + P-fibers are same speed as SA node to AV node

Why fo the P-fibers conduct faster?

they are bigger, and bigger fibers conduct impulse faster

What happens if the SA node fails?

AV node takes over, doesn’t fire as fast, contraction of atria is not as good b/c of the interatrial pathway

What does the AV node connect?

impulse between atria and ventricles

What is the AV node responsible for?

contraction of ventricle so blood can go out of heart to the body

What do ECGs record?

overall speed of electrical activity through the heart

What can NOT be seen from ECG + parts of the ECG

initiation of SA node impulse or AP, amplitude of atrial contraction, repolarization of atria

What features of electrical conduction are evident on ECG

depolarization of ventricles

During normal cardiac cycle, which is the point where left ventricular ejection fraction LVEF is determines?

LVEF defined as stroke volume divided by end-diastolic volume

What is cardiac output?

L/min of blood being pumped

Venous Return

rate of bloodflow back to heart

Preload

Afterload

Systole

contraction phase (1/3)

Diastole

relaxation (2/3)

Does parasympathetic or sympathetic impact ventricular contraction

sympathetic

What is intrinsic control in stroke volume

the extent of venous return

what is extrinsic control in stroke volume

extent of sympathetic stimulation of the heart

Cardiac Output =

Heart Rate x Stroke Volume

Will increasing blood volume increase cardiac muscle contractions?

Yes

Which nerve is para sympathetic stimulation

Vegas Nerve

How does increase in heart rate occur after sympathetic stimulation

increased rush of Na and Ca in pacemaker cells, AV node delay is shortened, Everything is sped up. relax faster too via circa pump

When would cardiac output increase?

Heavy exercise, fight or flight response

Increased end diastolic volume correlates to increased SV true or false

true

What is the advantage of length-tension relationship

both sides have equalized output

Why is force in left ventricle greater than right

left has to pump through higher resistance, and has thicker wall = more muscle, more force, more tension

Equation for ejection fraction =

SV/EDV (end diastolic volume)

What would happen if B_1 blocker given to heart

Slows down the effecti? idk needd to ask

What can cause high bp

afterload

Why does sodium increase bp

Name the layers of the artery

______ are major resistance vessels

arterioles - they change size and radius based on metabolic needs. ex: when exercising, they relax

What is the most potent vasodilating paracrine released by arteriolar endothelial cells

Nitric Oxide - is a paracrine because its produced by endothelial cells and is released in same area…also produced by other cells

What is a vasoconstrictor

Endothelin

When is acetylcholine released?

parasympathetic activity

What do our vessels do when it is cold?

vasocontrict

Are the arterials influenced by parasympathetic?

No. they only sense how much activity, not what activity

What is strength of constriction dependent on?

Ca, cold, angiotensin 2, oxygen, sympathetic stimulation, decreased tissue activity, CO2, H+

When does vasodilation occur?

increased tissue activity, decreased oxygen and decreased symp.

Local chemical changes act on the vascular endothelium with paracrines like

nitric oxide, endothelin, angiogenesis, ex: body can release nitric oxide to get past a blockage in the blood - dialates vessels

Look at reactive hyperemia chart

What does histamine do?

dialates arterioles

Why is histamine released?

when injured, or allergy. rushes blood to that area. take anti histamine tells body to stop reacting to that injury

• when u have a wound, increase in blood flow to wound happens = increase in fluid in the area that cant return back to heart

• too much can lead to a delay in recovery

What is myogenic response?

• response of arteriole dilation

What happens during sympathetic

constriction everywhere but the blood

What are the receptors of arteriolar smooth muscle adrenergic?

alpha 1 and beta 1

NE acts on a1 to vasoconstrict

E acts on b2 to vasodilate

What does vasopressin do?

What does angiotensin 2 do?

water balance; salt balance

Capillaries have small water filled pores for?

small water soluble ions, glucose, AA can pass through

What is the difference in brain capillaries?

Blood brain barrier→ brain capillaries are joines by tight junctions. NO pores

Histamine increases ________ permeability

capillary

What is capillary blood flow based on?

gradients

Metarteriole

main channel from arteriole to venule

Review fig 10-20 pg 365

What quantifies passive diffusion?

Fick’s law - understand

Bulk Flow equation

ECF distribution

Ultrafiltration for ECF distribution

fluid moving out of capillary into interstitial space

pi_C

Plasma colloid osmotic (oncotic) pressure is based on protein concentration inside the capillary

Find reabsorption or the ultrafiltration: reabsorption will result in a negative

outward pressure - inward pressure????

How to increase flow out of capillary

decrease protein in the interstitial space, increase capillary pressure

Primary lymphatics

Open flaps + fenestrations allow for fluids and proteins to connect

Secondary lymphatic

have valves to help prevent backflow. Can contract on their own b/c made of smooth muscles. Both go against the gradient

What is lymph?

in lymphatics, protein fluids, nothing much, lower viscosity than blood in capillaries

When does edema occur

too much ISF is accumulating

how will the following impact hydrostatic and oncotic pressure

1. red. conc of plasma proteins, reduced oncotic pressure = LESS reabsorption = less fluids in ISF

2. Inc. permeability of capillary walls, caused by histamine, ultrafiltration increases

3. inc. venous pressure, causes edema, not enough reabsorption happening, Net exchange pressure wouldnt be negative

4. blockage/cant pump lymph vessels

What are venules

beginning of venous structure where reabsorption occurs w. very low resistance: kinda just pass the blood

Veins

hold majority of blood until body needs it

Veins vs Arteries

veins are lower pressure, arteries are higher pressure. veins also have valves and would be limited to that region

Why does skeletal muscle contraction not affect arteries but affect veins

arteries hvae thicker wall, skeletal muscles can collapse on the veins

______ activity causes vains to constrict

sympathetic - so when you stand up, need to get up and move

How do varicose veins occur

venous valves become incompetent/insufficient. not opening and closing properly