Heart

Question 1

Pulmonary circuit

Answer 1

Carried blood to and from the gas exchange surfaces of the lungs

Question 2

Systemic circuit

Answer 2

Transports blood to and from the rest of the body

Question 3

Arteries

Answer 3

Efferent vessels; carry blood away from the heart

Question 4

Veins

Answer 4

Afferent vessels; return blood to the heart

Question 5

Right atrium

Answer 5

Receives blood from the systemic circuit and passes it to the right ventricle which then pumps blood into the pulmonary circuit

Question 6

Left atrium

Answer 6

Collects blood from the pulmonary circuit and empties it into the left ventricle, which pumps blood into the systemic circuit.

Question 7

Pericardial sac

Answer 7

Surrounds the heart. Dense collagen fibers.

Question 8

Epicardium

Answer 8

Visceral pericardium that covers the outer surface of the heart.

Question 9

Auricle

Answer 9

Expandable extension of an atrium is called this. Reminds of the external ear

Question 10

Coronary sulcus

Answer 10

Deep grove, marks the border between the atria and the ventricles

Question 11

Myocardium

Answer 11

Muscular wall of the heart, forms the atria and ventricle. The layer contains cardiac muscle tissue, blood vessels, and nerves. I’m

Question 12

Endocardium

Answer 12

Covers the inner surfaces of the heart, including those heart valves.

Question 13

Intercalated discs

Answer 13

Interlocking membranes of adjacent cells are held together by desmosome and linked by gap junctions. Contraction from cell to cell

Question 14

Atrioventricular valves (av)

Answer 14

Folds of fibrous tissue that extend into the openings between that atria and ventricles. They permit blood to flow only on direction. Atria to the ventricles.

Question 15

Coronary arteries

Answer 15

Originate at the ascending aorta and at the aortic sinuses. Blood pressure here is the highest in the systemic circuit.

Question 16

Conducting system

Answer 16

A network of specialized cardiac muscle cells that initiates and distributes electrical impulses.

Includes: SA node- wall of right atrium
AV node: junction between the atria and ventricles
Conducting cells: interconnect the two nodes and distribute the contractile stimulus throughout the myocardium.

Question 17

Cardiac physiology

Answer 17

Heartbeat; the entire heart contracts- first the atria and then ventricles. Two types of cardiac muscle cells are involved in a normal heartbeat.

1. Specialized muscle cells of the conduction system control and coordinate
2. Contractile cells produce powerful contraction that propel blood

Question 18

The SA node (sinoatrial)

Answer 18

Embedded in the posterior wall of the right atrium. Contains pacemaker cells which establish the heart rate.
•connected to the larger AV node by the intermodal pathways in the atrial walls.

Question 19

The AV node (atrioventricular)

Answer 19

Sits within the floor of the right atrium near the opening of the coronary sinus. The impulse slows as t leaves the intermodal pathways and entire the AV node, because nodal cells are smaller in diameter then conducting cells.

Question 20

Cardiac cycle

Answer 20

• period between the start of one heartbeat and the beginning of the next.
• systole- contraction, the chamber contractions and pushes blood into an adjacent chamber or into an arterial trunk. Systole is followed by diastole
• diastole- or relaxation. During diastole, the chamber fills with blood and prepares for the next cardiac cycle.

Question 21

End diastolic volume

Answer 21

How full a ventricle is when it starts to contract

Question 22

End systolic volume

Answer 22

How much blood remains in a ventricle after it contracts

Question 23

EDV

Answer 23

Amount of blood in a ventricle at the end of diastole, just before contraction begins.
Two factors of this volume: filling Time and venous return

Question 24

Filling time

Answer 24

Duration of ventricular diastole.

The faster the heart rate, the shorter is the time available for filling.

Question 25

Preload

Answer 25

Degree of stretching in ventricular muscle cells during ventricular diastole. Preload is directly proportional to the EDV: the greater the EDV, the larger the preload.

Question 26

Atrial reflex

Answer 26

Involves adjustments in heart rate in response to an increase in the venous return(the amount of blood returning to the heart through veins).

Question 27

ESV

Answer 27

After the ventricle contracted and ejected the stroke volume, the amount of blood that remains in the ventricle at the end of ventricular systole is the ESV. Determined by preload, contractility and after load

Question 28

Electrocardiogram

Answer 28

Electrical events in the heart are powerful enough to be detected by electro nodes on the surface of the body.

Question 29

Artial systole | Eight steps in cardiac cycle

Answer 29

Artial contraction begins | Right and left AV valves are open

Question 30

Atria eject blood into ventricles

Answer 30

Filling ventricle

Question 31

Artial systole ends

Answer 31

AV valves close | Known as end-diastolic volume (EDV)

Question 32

Ventricular systole

Answer 32

Isovolumetric (volumes of ventricles do not change) ventricular contraction Pressure in ventricles rises AV valves shut

Question 33

Ventricular ejection

Answer 33

``` Semilunar valves open Blood flows into pulmonary and aortic trunks Stroke volume(sv)=60% of end diastolic volume ```

Question 34

Ventricular pressure falls

Answer 34

Semilunar valves close

Question 35

Ventricular diastole

Answer 35

Ventricular pressure is higher than atrial pressure All heart valves are closed Ventricles relaxes (isovolumetric relaxation)

Question 36

Cardiac output

Answer 36

Heart rate x stroke volume If heart rate goes up, stroke volume goes down or heart rate goes down, stroke volume goes up If heart rate goes up diastole, end diastolic volume will go down. Stroke volume should go up, heart rate should go down. High EDV which increase stroke volume which makes heart rate go down

Question 37

Medulla oblongata

Answer 37

Cardioacceleratory center: controls sympathetic neurons(increase heart rate) Cardioinhibitory center: controls parasympathetic neurons(slows heart rate)

Question 38

Effects on SA node

Answer 38

ACh (parasympathetic stimulation)- slows the heart | NE(sympathetic stimulation)-speeds the heart

Question 39

EDV and stroke volume

Answer 39

• At rest EDV is low Myocardium stretches less Stroke volume is low •with exercise EDV increases Stroke volume increases Myocardium stretches more

Question 40

Three factors that affect ESV

Answer 40

You want this to be low. EDV high, stroke volume high. Preload: ventricular stretching during diastole Contractility: forced produced during contraction, at a given preload.