Cardiovascular

Question 1

Arteries everywhere except heart

Answer 1

Carry oxygenated blood. Pressure storers

Question 2

Veins everywhere except heart

Answer 2

Carry deoxygenated blood. Volume storers

Question 3

Pulmonary artery

Answer 3

Carries deoxygenated blood from the heart to the lungs

Question 4

pulmonary vein

Answer 4

carries oxygenated blood from the lungs back to the heart

Question 5

role of vascular system

Answer 5

partition blood from heart to different organs and tissues What does this allow us to do? 1. Transports waste (urea, kidney function) 2. Thremoregulation - controls blood flow to skin 3. Transport hormones 4. Distribute nutrients 5. Move CO2 and O2

Question 6

arteries vs veins vs capillaries anatomy

Answer 6

Arteries: Contain the thickest layer of elastic and smooth muscle, allowing them to contract and generate the most pressure.

Veins: Contain a thin layer of elastic so when blood goes in, veins give and you don’t get a lot of pushback - volume storers. Also contain one-way valves to prevent backflow. We don’t worry about backflow in the arteries because the pressure is higher.

Capillaries: Just a thin layer of endothelium, maximizing gas exchange.

Question 7

Anatomy of the heart and blood flow

Answer 7

–Blood enters heart on the right side via superior vena cava (collects blood from the top of body) and inferior vena cava (collects blood from lower part of body)

–Blood fills the right atrium passively. When pressure in right atrium is large enough, it flows through the tricuspid valve into the right ventricle.

–Right ventricle contracts (ventricular systole), and blood flows through the pulmonary valve to the lungs

–Blood is oxygenated in the lungs

–Blood returns to the left side of the heart via the pulmonary veins and collects in the left atrium

–When pressure in the left atrium is greater than pressure in the left ventricle, blood flows down into the left ventricle through the bicuspid valve

–Left ventricle contracts –> bicuspid valve closes and aortic valve opens

–Oxygenated blood flows out of aorta to the rest of the body

Question 8

Superior vena cava

Answer 8

carries deoxygenated blood from the upper part of the body to the right atrium

Question 9

inferior vena cava

Answer 9

carries deoxygenated blood from the lower part of the body to the right atrium

Question 10

pulmonary valve

Answer 10

blood must flow from the right ventricle up through the pulmonary valve to reach the veins

Question 11

bicuspid valve

Answer 11

separates the left atrium from the left ventricle

Question 12

Aortic valve

Answer 12

blood flows from the left ventricle up through the aortic valve to the rest of the body

Question 13

tricuspid valve

Answer 13

separates the right atrium from the right ventricle

Question 14

Right ventricle vs. left ventricle

Answer 14

The left ventricle is much larger because it needs to generate enough pressure to pump blood out to the whole body, while the right ventricle only needs to pump blood to the lungs.

Question 15

chordae tendineae

Answer 15

muscles that stabilize the AV valves to help keep them closed and prevent backflow

Question 16

coronary artery and coronary vein

Answer 16

provide the heart’s own circulation

Question 17

ventricular systole

Answer 17

ventricular contraction

Question 18

ventricular diastole

Answer 18

ventricular relaxation

Question 19

Cardiac output

Answer 19

=Heart Rate x Stroke Volume

= beats/min x mL/beat

=mL/min

Question 20

What does our closed circulatory system with the heart allow us to do?

Answer 20

1. Variable cardiac output - we can couple cardiac output to metabolic rate
2. We can partition blood

Question 21

How do we make the heart contract?

Answer 21

We use electrical signals. Mechanical activity follows electrical activity. We have 2 types of cells for this:

1. Conducting fibers
2. Contracting fibers

Question 22

Conducting fibers

Answer 22

specialized muscle cells that conduct electrical activity/information and generate action potentials that drive contractile cells

Question 23

Contracting fibers

Answer 23

muscle cells that do the contraction of the heart - make up the majority of heart cells

Question 24

Electrical pathway in the heart

Answer 24

1. SA node sets the baseline rhythm and needs no outside impulse
2. Spreads to the AV node, where the signal slows to let muscle contraction of the atriums catch up
3. Moves through Bundle of His fibers down to the bottom of the heart
4. From bottom of heart is carried back up via Purkinje fibers, which triggers contraction of the ventricle

**Contraction of ventricle happens from the bottom up to get all the blood bacvk to the valves

Question 25

Gap junctions

Answer 25

Allow the electrical signal to spread through the heart. This means not every cardiac cell needs nervous input

Question 26

myogenic

Answer 26

the heart is myogenic, which means it has its own pacemaker (the SA node)

Question 27

Stroke volume

Answer 27

=End diastolic volume - residual volume

–End diastolic volume = the blood in the ventricles just before they contract. This is the amount of blood in the ventricles when they are full

–Residual volume = the blood in the ventricles after contraction. We have some blood left in there, which gives us a reserve of blood.

–Stroke volume is the amount of blood pumped from the left ventricle per beat

Question 28

Ejection function

Answer 28

=Stroke volume/End diastolic volume

Question 29

cardiac work

Answer 29

the area under the PV diagram of the heart

Question 30

Preload vs. Afterload

Question 31

Regulation of cardiac system

Answer 31

1. Neural regulation
2. Baroreceptors/Chemoreceptors

Question 32

neural regulation of cardiac system

Answer 32

Occurs via the autonomic nervous system using both the parasympathetic and sympathetic

Question 33

Parasympathetic nervous system control of cardiac system

Answer 33

–Parasympathetic nervous system - “rest and digest”

–The vagus nerve is part of the parasympathetic nervous system and innervates SA node and AV node

–Decreases Heart rate (negative chonotropic effects)

–Decreases force of contraction (negative inotropic effect)

–Uses acetylcholine as neurotransmitter

–Overall result: decrease in cardiac output

Question 34

chonotropic effects

Answer 34

–Change the heart rate

–Positive chonotropic effect = increase heart rate

–Negative chontropic effect = decrease heart rate

Question 35

Inotropic effect

Answer 35

–effects strength of contraction (of heart)

–Positive inotropic effect = increases strength of contraction

–Negative inotropic effect = decreases strength of contraction

Question 36

Sympathetic Nervous system control of cardiac system

Answer 36

–“fight or flight”

–Positive chonotropic effect –> increased heart rate

–positive inotropic effect–> increased force of contraction

–Overall: increases cardiac output

–Primary neurotransmitter: norepinephrine

Question 37

Cardiac Output Regulation

Answer 37

1. Baroreceptors - found in carotid and aorta and measure blood pressure. If blood pressure drops, baroreceptors send info to medulla, medulla increases sympathetic activity and decreases parasympathetic activity to increase cardiac output
2. Chemoreceptors - measure blood gases on arterial side of medulla. If pO2 drops or pCO2 increases, medulla increases sympathetic response and decreases parasympathetic response –> increased respiratory minute volume–> increased cardiac output
3. Exercise - can override autonomic nervous system and increase cardiac output

Question 38

what happens when you increase heart rate and thus cardiac output?

Answer 38

Period of diastole will shorten and there’s an increase in venus return.

Question 39

Frank Starling Law

Answer 39

–The force of contraction of heart is proportional to stretch of myocardial fibers

–If you get more blood in chambers, the fibers will stretch more, and there will be a greater force of contraction

Question 40

Venous pressure and flow

Answer 40

–Cardiac output relies on venous return and venous return relies on venus pressure

Question 41

what controls venus pressure

Answer 41

1. Sympathetic veno constriction - sympathetic nervous system releases epinephrine that acts on veins as well as heart. In the veins, epinephrine causes smooth muscle contractions which increase venus pressure and increase blood flow back to heart
2. Skeletal muscle pump - during exercise you contract muscle –> constricts blood vessels –> increase venus pressure –> blood back to heart

Question 42

4 methods by which materials cross capillary walls

Answer 42

1. pinocytosis - proteins
2. diffusion or transport through capillary cell membranes - done by O2 and CO2 and small lipid-soluble molecules
3. movement through pores in the cells called fenestrations - proteins
4. movement through the spaces between the cells - done by water-soluble substances