Anatomy & Functioning of the Heart

Question 1

What is the major portion of the heart called?

Answer 1

Myocardium

It consists largely of cardiac muscle

Question 2

How many chambers does the heart have? What are they called?

Answer 2

4 chambers in total

2 upper thin-walled atria

2 lower thick-walled ventricles

Question 3

What are the purpose of the valves in the heart?

Answer 3

Prevent the backflow of blood

Question 4

What are the valves between the atria and the ventricles called?

Answer 4

Atrioventricular valves

(A-V Valves)

Question 5

What are the valves in the aorta and pulmonary trunk called?

Answer 5

semilunar valves

Question 6

What do the chordae tendineae do?

Answer 6

They ensure the correct operation of the AV valves as the heart beats.

Question 7

What is the right side and the left side of the heart separated by?

Answer 7

Septum

Question 8

Where does the cardiac muscle of the heart get its oxygenated blood from?

Answer 8

Coronary Arteries

Question 9

What is an artery?

Answer 9

A vessel that travels away from the heart

(usually but not always, carrying oxygenated blood)

Question 10

What is a vein?

Answer 10

a vessel that travels back to the heart

(usually but not always, carrying deoxygenated blood)

Question 11

What does systole refer to?

Answer 11

contraction of the heart muscle

Question 12

What does diastole refer to?

Answer 12

the relaxation of the heart muscle

Question 13

What is the cardiac cycle?

Answer 13

The 2 atria contract together then the 2 ventricles contract together

1 heart beat

• Atrial systole, ventricular diastole
• Atrial diastole, ventricular systole
• Atrial diastole, ventricular diastole

Question 14

Describe the heart sounds

Answer 14

Heartbeat sounds are described as lub-DUPP

the lub sound is due to the closing if the AV valves

the DUBB sound is due to the closing of the semilunar vlaves

Question 15

What is it called when the valves don’t work as they should and blood ends up backflowing?

Answer 15

a heart murmur

Question 16

How do you determine heart rate or pulse?

Answer 16

It is the number of times your heart beats per minute (bpm)

As the left ventricle contracts, blood enters your arteries and the artery dilates to accommodate the blood flow. Its what you feel as your pulse.

Question 17

What is your resting heart rate?

Answer 17

The rate at which your heart beats when you are not exercising. Your oxygen and glucose demands are at their lowest.

If you are more fit you often have a lower resting heart rate because your heart muscle is stronger and can pump more blood per beat

Question 18

What is cardiac output?

Answer 18

The volume of blood pumped with each heartbeat

Cardiac Output (mL/min) = Stroke volume (mL/beat) x Heart Rate (bpm)

Question 19

What changes occur in the circulatory system as a result of long-term exercising?

Answer 19

1. A stronger heart
2. A increase in blood volume
3. An increase in red blood cells and hemoglobin
4. Arteries maintain their elasticity
5. An increased growth of capillaries into the muscle.

Question 20

What does it mean to have an increase in red blood cells and hemoglobin?

Answer 20

it means your blood has a greater ability to carry O₂ to the tissues and remove waste CO₂. There fore your heart does not need to pump that often.

Question 21

What does it mean to have an increase in growth of capillaries into the muscle?

Answer 21

This means an increase in blood flow, O₂, and glucose delivery to the muscles as well as increased CO₂ removal. Adding an extra pound of body fat means you will need to grow over a kilometre of capillaries to supply it. That means the heart has to work harder to move blood through the body.

Question 22

What does it mean when the heart muscle hypertrophies?

Answer 22

It gets bigger and stronger

Question 23

What measures blood pressure?

Answer 23

A blood pressure cuff called a sphygmomanometer.

Question 24

How does a blood pressure cuff work?

Answer 24

It is wrapped around your upper arm.

Then it is inflated to a pressure higher than your systolic blood pressure

they release the pressure in the cuff and listen for the first sound in the stethoscope - That is the systolic pressure

They keep deflating and listening. When the noise goes away, that is your diastolic pressure

Question 25

How is blood pressure recorded?

Answer 25

Systolic pressure/Diastolic pressure

Question 26

What is a healthy blood pressure?

Answer 26

120/80 or less than in either numbers.

Question 27

When looking at blood pressure, which is more important? the top (systolic) or the bottom (diastolic)?

Answer 27

Typically more attention is given to the top number. In most people, systolic pressure rises with age because the arteries get stiffer and there has been more time for plaque to build up.

Question 28

What is hypertension?

Answer 28

High blood pressure

Question 29

What is hypotension?

Answer 29

low blood pressure

Question 30

What causes hypertension (high blood pressure)?

Answer 30

Smoking - Nicotine acts as a vasoconstrictor Stress - acts as a vasoconstrictor Diabetes - increases blood volume Too much salt - increases blood volume Lack of physical activity - vessel become less elastic Older Age - vessels become less elastic Genetic/Family History - good vs bad cholesterol & plaque build up.

Question 31

What is blood pressure?

Answer 31

The measure of the force of blood pushing against artery walls

Question 32

What is Artherosclerosis?

Answer 32

Fatty deposits (Plaques) that build up in the smooth muscle layers of the arteries Reduces the flow & stiffens the artery walls (less elastic)

Question 33

How does diabetes increase blood volume?

Answer 33

excess sugar in the blood makes the blood hypertonic and water diffuses into the blood vessel.

Question 34

How does too much salt in the diet increase blood volume?

Answer 34

excess salt in the blood makes the blood hypertonic and water diffuses into the blood vessel.

Question 35

What causes hypotension? (Low blood pressure)

Answer 35

1. Major bleeding 2. Dehydration 3. Shock

Question 36

How does shock cause hypotension?

Answer 36

massive vaso-dilation (many blood vessels open up at the same time). It decreases blood flow to major organs and can be dangerous.

Question 37

How are blood pressure and heart rate related?

Answer 37

There is no good correlation. Measuring pulse rate does not indicate high or low blood pressure.

Question 38

How does your body maintain its heartbeat?

Answer 38

The heart can beat independently of any nervous stimulation (INTRINSIC) There are 2 places in the wall of the right atrium where there is special tissue that can control the beating of the heart.

Question 39

What are the tissues in the right atrium that control the heartbeat?

Answer 39

The sino-atrial node (SA node) is the pacemaker since it starts the contraction of the right atrium causing a wave of contraction to pass through all the atrial tissue The wave reaches the atrio-ventricular node (AV node) The AV node immediately passes this wave down the septum and up the Purkinje fibres causing the ventricles to contract from the bottom upwards

Question 40

What are Purkinje Fibres?

Answer 40

Fibres in the ventricles that ensure the ventricle contract from the bottom.

Question 41

How does the autonomic nervous system control the heartbeat?

Answer 41

The heart rate centre is in the medulla oblongata of the brain There are 2 autonomic systems that act like "ON" and "OFF" switches **Sympathetic nervous system** - "Fight or Flight" increase heart rate/increases blood pressure **Parasympathetic nervous system** - "Rest & Digest" slows down heart rate/decreases blood pressure