The Heart

Question 1

The heart, greater blood vessels, trachea & esophagus is situated in the chest in a cavity called _____

The heart itself is in a cavity slightly to the left side in a subdivision of the _______ and is known as the ________ cavity

Answer 1

Mediastinum x2

Pericardial cavity

Question 2

The membranous structure that surrounds the heart is known as the ______

That structure is composed of two layers, the ______ ____ , a tough outer layer that attaches heart to surrounding structures & the ____ _____, a thing inner serous membrane that prouduces serous fluid

Answer 2

Pericaridum

Fibrous pericaridum

Serous pericaridum

Question 3

Explain the 3 spots of heart

Apex
Base
Diaphragmatic surface

Answer 3

Apex, base,

Question 4

Whats the difference between the pulmonary circuit and the systemic circuit

Answer 4

Pulmonary= heart-> lungs -> blood

Systemic= heart -> body-> heart

Under higher pressure then pulmonary circulation

Question 5

The pericardium is the outmost layer of the heart what are the other two layers?

Answer 5

1. pericardium -> fibrous pericardium+ serous pericardium (also has two layers -> visceral or parietal serous pericardium
2. Myocardium
3. Endocardium

Question 6

What is pericarditis?

Answer 6

Inflammation of the pericardium causing serevre substernal pain, effusion

Question 7

Your asked to check if a patient has cardiac tamponande by checking becks triad, whats becks triad?

Answer 7

Low bp
Muffeled heart sounds
Distented neckveins/ juglar pressure

Question 8

Muscular ridges found in the heart are what?

Answer 8

Pectinate muscle

Question 9

There is pectinate in the atrium and resembles muscular ridges, a similar muscle is found but differently named in the right ventricle, what is it called?

Answer 9

The papillary muscle

Question 10

______ _____ attach directly to the papillary muscle and work together to open and close the tricuspid and bicuspid valves

Answer 10

Chordae tendinae

Question 11

What vein returns oxygenated blood to the heart?

Answer 11

Pulmomary vein (comes from lung to heart)

Question 12

What are the two cells found in cardiac muscle tissue?

Answer 12

Pacemaker cells

Contractile cells

Question 13

What are the 3 types of pacemaker cells?

Answer 13

Sinoatrial node (SA Node)

Atrioventricular node (AV Node)

Purkinje fibre system (AV bundle, R & L bundle branches & terminal branches)

Question 14

___ node is the normal pacemaker of the entire heart; electrical rhythums created by this node are known as sinus rhythums.

Answer 14

SA Node

If SA node ceases to funtion the AV node can successfully pace the heart

Question 15

What are the implications of the plateu phase after a contractile cell preforms an action potential

Answer 15

The plateau phase lengthens cardiac action potential to about 200 to 300 ms call,

This slows heart rate and provides time required for heart to fill with blood
and also increases the strength of hearts contraction (startlings law of the heart)

Question 16

Cardiac valves are one way doors used to direct blood flow,

both AV valves are forced _____ by blood _______

Both Semilunar valves are forced ______ by ______ blood

Answer 16

Forced Shut by blood pushing agiasnt them

Forced open by outgoing blood

Question 17

What are the two main heart sounds?

Answer 17

Lub-> s1-> when AV valves close-> when ventricles contract-> louder at apex

Dub-> s2-> when semilunar vavlues close-> when ventricles relax

Question 18

Define these:

1. Heart rate
2. stroke volume.
3. cadiac output

Answer 18

1. Heart rate
   - beats per minute (cardiac cycles per min)

2.stroke volume.
-amount of blood pumped in one heart beat-> calculated as
EDV-ESV= SV

3. cadiac output
   - amount of blood pumped in one minute (SV x HR = CO)

Question 19

What 3 factors influence stroke volume?

Answer 19

1. Preload-> the length or degree of stretch in ventricular cells before they contract -> frank-stirling law-> explains relationship —>increased stretch = increased strength of contraction
2. Contractility-> hearts intrinsic pumping ability or abilty to generate tension-> Inotropic agents (medications) can affect contractility
3. Afterload-> refers to force that ventricles must overcome in order to eject blood into their respective arteries (resistance)
   - > largerly determined by BP in arteries of both pulmonary and systemic circuits