Unit 2-KA6

Question 1

Give the meaning of cardiac output

Answer 1

The volume of blood pumped through each ventricle per minute

Question 2

Describe how cardiac output is calculated

Answer 2

Cardiac Output=

Heart Rate x Stroke Volume

Question 3

State the location of the SAN in the heart

Answer 3

Wall at the top of the right atrium

Question 4

Describe the role of the SAN

Answer 4

Sets the rate at which cardiac muscle cells contract and generates an electrical impulse which is passed through the left and right atria to the AVN

Question 5

Describe the role of the AVN

Answer 5

Receives impulses from the SAN and send impulses that result in the simultaneous contraction of the ventricles (ventricular systole)

Question 6

Describe the effect of impulses from the sympathies and parasympathetic nerves on the heart

Answer 6

Sympathetic nerves-
release noradrenaline
increases the heart rate

Parasympathetic nerves-
release acetylcholine
decreases the heart rate

Question 7

Describe the state of the heart valves during ventricular systole

Answer 7

Ventricular systole-
closes AV valves
open SL valves

Question 8

Describe the state of the atrial and ventricular muscles during the diastolic stage of the cardiac cycle

Answer 8

Diastole-

muscles of atria and ventricles are relaxed

Question 9

Describe the function of the SL valves

Answer 9

SL valves prevent blackflow of blood back into the ventricles

Question 10

Name the stage or the cardiac cycle when the SL valves are open

Answer 10

Ventricular systole

Question 11

Name the instruments used to measure-
blood pressure
pulse rate

Answer 11

Blood pressure-
sphygmomanometer
Pulse rate-
pulsometer

Question 12

Five the meaning of the terms-
systolic pressure
diastolic pressure

Answer 12

Systolic pressure-
pressure the blood exerts on the arteries while the heart is contracting

Diastolic pressure-
pressure the blood experts on the arteries while relaxed

Question 13

Explain the change in blood pressure that occurs as blood flows through the circulatory system

Answer 13

Progressive decrease after leaving the heart

decrease in pressure due to arteries branching into arterioles/capillaries/smaller vessels and increase in surface area

Question 14

Give the terms used to deduce the condition in which an individual has persistently high blood pressure and name one disease or condition associated with it

Answer 14

Hypertension-

coronary heart disease/stroke

Question 15

Electrocardiograms are used to show heart activity.

Explain what allows an ECG to be produced and describe the appearance of a normal ECG trace

Answer 15

The electrical impulses generated in the heart produce currents that can be detected by an ECG
ECG is used to measure the electrical changes that take place in the heart-produces a PQRST wave

Question 16

Explain what causes the distinct waves obtained in a normal ECG trace

Answer 16

P-
wave of electrical pulses spreading over the atria from the SAN

QRS-
the electrical impulses through the ventricles

T-
the electrical recovery of the ventricles at the end of ventricular systole