Unit 2: Cardiovascular System

Question 1

what are the 4 major roles of the cardiovascular system

Answer 1

to transport oxygen from the lungs to the tissues;
to transport carbon dioxide from the tissues to the lungs;
to transport nutrients from the digestive system to other areas in the body;
to transport waste products from sites of production to sites of excretion.

Question 2

How many sections is the heart divided into? name them

Answer 2

4: right atria, left atria, right ventricle, left ventricle

Question 3

What is the function of the atrias of the heart

Answer 3

recieve blood from organs and pump blood down to ventricles. they are the collecting chambers of the heart.

Question 4

what is the overall functions of the two ventricles of the heart

Answer 4

pumping blood out from heart to rest of body and lungs

Question 5

where does the right atria pump out blood to

Answer 5

lungs

Question 6

where does the left atria pump out blood to

Answer 6

body (not lungs)

Question 7

What is pulmonary circulation

Answer 7

right side of heart pumps deoxygenated blood into lungs

Question 8

What is systemic circulation

Answer 8

left side of heart pumps oxygenated blood (from lungs) to rest of body

Question 9

What is coronary circulation

Answer 9

system of vessels that supply blood to heart muscle itself

Question 10

what is the muscle tissue that makes up the heart

Answer 10

myocardium

Question 11

What is the pacemaker of the heart

Answer 11

the SA node

Question 12

Explain the self-contraction of the SA node in the heart

Answer 12

inside cells there is an action potential. the inside of the action-potential is negative while the outside of the action-potential is positive. However, the heart has some leaky channels, that allow the spillage of sodium into the heart. When the inside reaches its threshold, all the gap junctions open and calcium is flooded into the hells. Calcium spreads throughout the heart, which causes a contraction.

Question 13

Define syncytium

Answer 13

when single cell is stimulated to contract, it causes all other cardiac muscle cells to contract too

Question 14

What is the heart rate monitored by

Answer 14

automatic nervous system

Question 15

How does electricity in heart cause top-down contraction

Answer 15

electrical signal spreads through both atria, causing atria to contract from top down and forcing blood into ventricles. Then, the electrical signal passes from atria into ventricles. ventricles then contract
from bottom up, forcing blood into aorta and pulmonary arteries

Question 16

What is an ECG and what does it do

Answer 16

measures electrical activity of heart
provides a graphical representation of electrical sequence of events that occur with each contraction of heart (draws each heart beat)

Question 17

What is a myocardial infarction

Answer 17

A heart attack: when blood supply to a region of the myocardium is reduced or cut off for prolonged period of time, myocardium tissue will be damaged or die

Question 18

What are the two phases of the cardiac cycle

Answer 18

diastole = phase of relaxation (heart is filling with blood)
systole = phase of contraction (heart contracts and ejects blood)

Question 19

What propels blood to circulate within heart and body

Answer 19

dramatic changes in pressure

Question 20

What is systolic blood pressure

Answer 20

pressure observed in arteries during contraction phase

Question 21

What is diastolic blood pressure

Answer 21

pressure observed in arteries during relaxation phase

Question 22

What are arteries

Answer 22

vessels with very thick muscular walls, which carry blood away from the heart to the different tissues and organs of the body.

Question 23

what are arterioles

Answer 23

The arterioles are smaller than the arteries and are important in the
regulation of blood distribution to the various tissues of the body. Arterioles are surrounded by rings of smooth muscle, and these rings can contract, constricting the arteriole and reducing the amount of blood flow, or relax, opening the arteriole and increasing the amount of blood flow.

Question 24

what are cappillaries

Answer 24

The capillaries are the smallest vessels within the body. It is in the capillaries where the main function of the cardiovascular system occurs, as well as the exchange of gases and nutrients with the tissues.

Question 25

What are venules and veins

Answer 25

Once blood travels through the capillaries, it then enters the venules. These vessels are small, thin-walled extensions of the capillaries. The venules lead into veins, which return blood to the heart for another trip throughout the vascular system. Veins become larger as they move away from the capillaries. Many venules come together to form larger veins, until they all come together to form either the superior or inferior vena cava.

Question 26

What is stroke volume (SV)

Answer 26

amount of blood ejected from left ventricle in single beat

Question 27

what are the three things that affect stroke volume

Answer 27

1. aortic blood pressure (as bp increase, sv decrease), 2. strength of venticular contraction (as strength increase, sv increase), 3. Amount of blood that flows into ventricle (as amount increase, sv increase)

Question 28

what is the Amount of blood that flows into ventricle determined by

Answer 28

venous return

Question 29

how does aortic blood pressure affect stroke volume

Answer 29

More pressure acting against the wall of the vessels will result in less blood leaving the heart and consequently a lower stroke volume

Question 30

How does the strength of a ventricular contraction affect stroke volume

Answer 30

Stronger contraction = more blood ejected

Question 31

how does the Amount of blood that flows into ventricle affect stroke volume

Answer 31

*Most important factor** More blood into the ventricle will cause it to stretch, this will result in a stronger contraction, increasing stroke volume

Question 32

what is venous return

Answer 32

how much blood gets back to the heart

Question 33

what are the 4 things that can affect venous return

Answer 33

increases due to: 1. venoconstriction 2. action of the skeletal pump muscle 3. thoracic pump 4. nervous stimulation of the heart

Question 34

how does venoconstriction affect venous return

Answer 34

Some veins are surrounded by a very thin layer of smooth muscle, this constricts at the onset of exercise (nervous and hormonal signals), causing blood to be ‘pushed’ back to the heart

Question 35

how does action of the skeletal muscle pump affect venous return

Answer 35

Contraction of skeletal muscle squeezes veins, due to the one-way valves in veins, this results in blood being pushed back to the heart

Question 36

how does the thoracic pump affect venous return

Answer 36

changes in pressure resulting from breathing cause blood found in abdominal veins to be sucked into veins of the chest/thoracic cavity

Question 37

how does nervous stimulation of the heart affect venous retun

Answer 37

More blood pumped out = more blood returned

Question 38

What is cardiac output

Answer 38

volume of blood pumped out of left ventricle in 1 minute (Q= SV x HR)

Question 39

how can cardiac output be increased

Answer 39

by increasing either heart rate or stroke volume, or both

Question 40

explain the blood flow of the heart

Answer 40

Blood enters right atrium from superior and inferior vena cavae Blood in right atrium flows into right AV valve into right ventricle Contraction of right ventricle forces pulmonary valves open Blood flows from pulmonary valve into pulmonary trunk Blood is distributed by right and left pulmonary arteries to the lungs, where it unloads CO2 and loads O2 Blood returns from lungs via pulmonary veins to left atrium Blood in left atrium flows through left AV valve into left ventricle Contraction of left ventricle forces aortic valve open Blood flows through aortic valve into ascending aorta Blood in aorta is distributed to every organ in the body, where it unloads O2 and loads CO2 Blood returns to heart via vena cavae

Question 41

What are the 3 parts to a ECG reading

Answer 41

P-wave, RQS Complex, and T-Wave

Question 42

what happens in the P-wave of an ECG

Answer 42

Firing of the SA node causes the atria to depolarize Atrial contraction begins Causes the pressure within the atria to increase Forces blood into the ventricles (only a fraction because the ventricles are already almost full from passive blood flow down the ventricles through the open AV valves) Atrial contraction completes Causes pressure within the atria to fall Causes the AV valves to close This produces the first heart beat sound Marks the beginning of systole

Question 43

What happens in the QRS complex of the ECG reading

Answer 43

Ventricular depolarization (already halfway when atrial contraction is complete) Ventricles start to contract Rapidly build up pressure in the ventricles. The semilunar valves remain closed, and the ventricles contract within a closed space Referred to isovolumetric contraction as no blood is ejected and ventricular volume is unexchanged Ventricular Ejection When ventricular pressures exceed the pressure within the aorta and pulmonary artery The aortic and pulmonary valves open and blood is ejected out of the ventricles Referred to as rapid ejection phase

Question 44

What happens in the T-wave of an ECG

Answer 44

Venticular repolarization: Ventricular pressure starts to fall and the force of ejection is reduced When the ventricular pressure drops below aortic and pulmonary pressure, the semilunar valves close This marks the end of systole and the beginning of dystole Close of these valves produce the second heart sound The ventricles relax with the valves closed, which causes another isovulmetric contraction The atria are being filled with blood and aortic pressure rise slowly Venticular filling starts when ventricular pressure drops below aortic pressure which causes the AV valves to open, allowing blood to flow down into the ventricles passively The atria contract to finish the filling phase

Question 45

What is the role of the AV Node

Answer 45

Passes electrical signal from atria to ventricles

Question 46

What passes the electrical signal from the bundle of His to the bottom of the ventricles

Answer 46

Purkinje fibers

Question 47

What is a specialized prtein that binds oxygen and carbon dioxide

Answer 47

hemoglobin

Question 48

what is the system of vessels that supply blood to the heart muscle itself

Answer 48

coronary

Question 49

pressure observed in the artieries during the contraction phase of the heart

Answer 49

systolic