BIOL 320 - CH 20 (Heart) Review

how big is the heart?

fist

where is the heart located?

mediastinum

between what ribs will you find the heart?

2 and 5

what is the heart’s orientation?

diagonal from the right shoulder to the left hip

where is the heart related to the diaphragm?

superior

where is the heart related to the midline?

to the left

where is the heart related to the sternum?

behind

where are the great vessels?

on top of the heart

where are the great vessels by related to the ribs?

rib 2

what vertebrae are the great vessels found near?

T4 and T5

what is the double walled sheath that wraps the heart?

pericardium

what is the average resting heart rate (RHR)?

40-60 bpm

average resting heart rate is influenced by what 2 components?

genetics and exercise

what prevents the heart from friction and wear and tear?

pericardium

what results in the pericardial cavity containing too much fluid?

pericarditis

what disease puts pressure on the myocardium?

pericarditis

list the layers of the pericardium from outside to inside

1. fibrous pericardium

2. parietal layer of the serous pericardium

3. pericardial cavity

4. heart wall

   1. visceral layer of serous pericardium (epicardium)

   2. myocardium

   3. endocardium

5. heart chamber

what lines the inside of the heart muscle?

epicardium

what is impermeable to gas?

epicardium

what prevents the heart from stealing the oxygen the blood that goes through it carries?

epicardium

what are the valves in the heart?

atrioventricular valves and semilunar valves

what valves are pushed open easily but then closed and held shut by pressure?

semilunar valves

what heart structure functions to allow blood into the ventricles easily, but prevents easy backflow into the atria?

atrioventricular (AV) valves

what connects to the atrioventricular (AV) valves to prevent their flaps from getting blown black into the atria?

chordae tendinae

what heart structure connects the chordae tendinae to the heart wall?

papillary muscles

what tightens when the ventricles contract?

chordae tendinae

when the heart is relaxed, what helps blood drain from the veins into the atria and ventricles?

gravity

what happens to squeeze the remaining blood into the ventricles?

the atria contract

when the ventricles contract, what pushes the AV valve flaps open?

pressure

when the ventricles contract, what do the papillary muscles do?

contract

when the papillary muscles contract, they help do what?

keep the atrioventricular (AV) valves closed

when the ventricles contract and the AV valves close, what does blood do?

find an alternate pathway to escape through the semilunar (SL) valves

when the heart relaxes after a contraction, what happens?

the cusps of the SL valves catch blood which provides pressure and weight to close the SL valves

what side of the valves does blood need to flow in order to close the valve?

concave

what makes heart sounds?

valves closing

what makes the lub sound?

AV valves close

what makes the dub sound?

SL valves close

what is caused by reflux in the heart?

heart murmur

what causes reflux in the heart?

valves not closing completely

what is reflux in the heart?

when blood flows back through the valve it just came from

what is the most common and dangerous cause of a heart murmur?

AV valves not working properly

what happens when the AV valves do not close correctly?

blood flows back from the ventricles into the atria

what is the narrowing/stiffening of a valve

valve stenosis

what causes valve stenosis?

genetics, endocarditis, or a buildup of calcium salt

valve stenosis leads to ___ in the heart.

leaks

when the heart leaks, its efficiency ___

decreases

what are the symptoms of valve stenosis?

overworked heart and fatigue

why does valve stenosis cause fatigue?

it prevents sufficient oxygen to get to tissues

what is the treatment of valve stenosis?

valve replacement

what types of valves can be used in valve replacement treatment of valve stenosis?

synthetic, pig, or cadaver

true/false: replacement valves may need to replaced multiple times

true

why may valves need to replaced multiple times?

growth or body changes

where are the sounds of the aortic semilunar valve heard?

2nd intercostal space at right sternal margin

what valve can you hear when using a stethescope at the top right area?

aortic semilunar valve

where are the sounds of the pulmonary semilunar valve heard?

2nd intercostal space at left sternal margin

what valve can you hear when using a stethescope at the top left area?

pulmonary semilunar valve

where are the sounds of the mitral (bicuspid)valve heard?

5th intercostal space in line with middle of the left clavicle

what valve can you hear when using a stethescope at the bottom left area?

mitral (bicuspid) valve

where are the sounds of the tricuspid valve heard?

right sternal margin of the 5th intercostal space

what valve sounds may also be heard over the sternum?

tricuspid valve

what valve sounds may also be heard over the left sternal margin in the 5th intercostal space?

tricuspid valve

what valve can you hear with a stethescope at the bottom right area?

tricusp valve

flow of blood through the heart

1. inferior/superior vena cava

2. right atrium

3. tricuspid valve

4. right ventricle

5. pulmonary semilunar valve

6. pulmonary trunk/arteries

7. lungs

8. pulmonary veins

9. left atrium

10. bicuspid/mitral valve

11. left ventricle

12. aortic semilunar valve

13. aorta

14. body

what is known as the “Widow Maker”?

bicuspid/mitral valve

why is the mitral valve known as the “Widow Maker”?

it is the most destructive if not working properly

the left coronary artery branches off into the ___

1. circumflex artery

2. anterior interventricular artery

the right coronary artery branches into the ____

1. right marginal artery

2. posterior interventricular artery

what are the 3 veins of the heart?

1. great cardiac vein

2. middle cardiac vein

3. small cardiac vein

all the veins of the heart drain into the ___

coronary sinus

the coronary sinus drains into what?

right atrium

what joins blood vessels?

anastamoses

true/false: anastamoses are needed in joints

true

why are anastamoses needed in joints?

joint compression

true/false: anastamoses are needed in the heart

true

true/false: anastamoses are needed in the lungs

true

true/false: anastamoses are needed in the brain

true

true/false: anastamoses are needed in the major abdominal organs (digestive tract)

true

is the heart skeleton fibrous or bony?

fibrous

what consists of a plate of fbrous connective tissue between the atria and ventricles?

heart skeleton

what makes up the fbrous rings around the heart valves?

heart skeleton

what are the functions of the heart skeleton?

1. support of the valves

2. electrical insulation between the atria and ventricles

3. muscle attachment site

what is responsible for the cell-to-cell contact of cardiac muscles?

intercalated disks

what allows the electrical signal from the SA node to go to the rest of the heart?

intercalated disks

what holds together cardiac muscle cells

desmosomes

what allows ions to pass from cell to cell?

gap junctions

what is a single unit of a cardiac muscle?

functional syncytium

flow of the electrical system in the heart

1. SA node

2. AV node and both atria

3. AV bundle (bundle of His)

4. left and right bundle branches

5. Purkinje finbers

what runs automatically in the heart?

pacemaker cells

what allows pacemaker cells to run automatically?

a resting membrane potential that slowly depolarizes due to leaks

what happens to the channels when skeletal muscle depolarizes?

1. Na⁺ channels open

2. K⁺ channels begin to open

what happens to the channels when skeletal muscle repolarizes?

1. Na⁺ channels close

2. K⁺ channels continue to open

3. K⁺ channels close at the end of repolarization

what happens to the channels when cardiac muscle depolarizes?

1. Na⁺ channels open

2. K⁺ channels open (some)

3. Ca²⁺ channels begin to open

what happens to the channels when cardiac muscle begins early repolarization?

1. Na⁺ channels close

2. K⁺ channels open (some)

what happens to the channels when cardiac muscle reaches the plateau phase?

Ca²⁺ stay open

what happens to the channels when cardiac muscle goes through final repolarization?

1. Ca²⁺ channels close

2. K⁺ channels open

3. K⁺ channels close at the end of repolarization

the length of the plateau phase of a cardiac action potential depends on?

how long calcium is released for

at the start of an action potential, what is the distribution of ions?

K⁺ in, Na⁺ out

what percent of cardiac cells are autorhythmic?

1

what percent of the heart drives all the activity of the heart?

1

what is the beginning of of the autorhythmicity of the pacemaker cells?

1. a small number of Na⁺ channels open

2. K⁺ channels begin to close

3. Ca²⁺ channels begin to open