lesson 8 - monitoring the circulatory system

Question 1

What are the two nodes of the heart

Answer 1

1. The sinoatrial node (SA) - aka the pacemaker.
2. The atrioventricular node (AV)

Question 2

What does the sinoatrial node do?

Answer 2

The SA node stimulates the muscle cells to contract and relax rhythmically. It also generates an electrical signal that spreads over the atria so they contract at the same time

Question 3

What does the atrioventricular node do?

Answer 3

The signal from the SA node goes to the AV node, then to the bundle of His, then to the purkinje fibres which cause the contraction of the ventricles

Question 4

What sound does the heart make?

Answer 4

The sounds “lub” and “dub” are made by the closing of valves.

Question 5

How is the “lub” sound made

Answer 5

It’s from the closing of atrioventricular valves (tricuspid and bicuspid)

Question 6

How is the “dub” sound made

Answer 6

It’s from the closing of the semilunar valves (aortic and pulmonary)

Question 7

What are the atrioventricular valves

Answer 7

Tricuspid and bicuspid valves

Question 8

What are the semilunar valves

Answer 8

Aortic and pulmonary valves

Question 9

How many spikes are in the electrocardiogram and what are they?

Answer 9

There are 3 spikes: The P wave, the QRS complex, and the T wave

Question 10

When does the P wave spike?

Answer 10

When the sinoatrial node fires and the atrias contract

Question 11

When does the QRS complex spike?

Answer 11

It begins when the atrioventricular node stimulates the ventricles to contract and the atrioventricular valves close, producing the first heart sound “lub”

Question 12

When does the T wave spike?

Answer 12

It occurs when the ventricles relax again, and the semilunar valves close to produce the second heart sound “dub.” The relaxation of the ventricles is followed by the next firing of the sinoatrial node for the next heartbeat

Question 13

What is systolic pressure?

Answer 13

Maximum pressure in arteries when the ventricles contract to push blood forward

Question 14

What is blood pressure?

Answer 14

Pressure that blood exerts on blood vessel walls

Question 15

What is diastolic pressure?

Answer 15

Lowest pressure in arteries when the ventricles fill with blood

Question 16

How is blood pressure measured?

Answer 16

Using a sphygmomanometer (sfig-mom-an-om-eter), a blood pressure cuff which is placed on an artery on the arm

Question 17

How is blood pressure recorded?

Answer 17

mmHg (millimeters of mercury) as systolic of diastolic pressure.

Question 18

What is the average blood pressure?

Answer 18

The average blood pressure is 120/80

Question 19

What factors affect blood pressure?

Answer 19

Genetics, physical activity, stress, body temperature, diet, and medication

Question 20

What is hypertension and what risks does it include?

Answer 20

Hypertension is a continous high blood pressure which causes damage to the arteries. It allows a higher risk of heart attack, stroke, and kidney failure

Question 21

What is cardiac output?

Answer 21

The volume of blood pumped by the heart measured in mL/min

Question 22

What does cardiac output indicate?

Answer 22

It indicates the total level of muscle work, how easily the heart fills with blood, and distensibility (stretchiness) of the ventricles

Question 23

What is stroke volume?

Answer 23

The amount of blood pumped out of the heart with each heartbeat

Question 24

How do you calculate cardiac output?

Answer 24

Heart rate x stroke volume = cardiac output

Question 25

What is the average stroke volume?

Answer 25

(70bpm)(70mL)=4900mL/min

Question 26

What is cardiovascular fitness?

Answer 26

The capacity of the heart, lungs, and blood vessels to deliver oxygen to working muscle tissues so they can maintain prolonged physical work.