Heart Activity

Question 1

Why is the heart referred to as a double pump?

Answer 1

Double circulation: heart-> lungs and heart->tissues

Question 2

Where does de-oxygenated blood return to the right atrium via?

Answer 2

The superior vena cava (from upper body), inferior vena cava (from lower body), coronary sinus (from heart muscle)

Question 3

How does de-oxygenated blood get to the lungs?

Answer 3

via pulmonary artery for oxygenation and removal of carbon dioxide (by gaseous exchange)

Question 4

What are the 4 chambers?

Answer 4

2 atria (right & left) 2 Ventricles

Question 5

Where is the coronary sinus and what does it do?

Answer 5

At the back of the atrium. Empties blood from heart veins (muscle) into the right atrium

Question 6

What are the pulmonary and aortic valves known as?

Answer 6

Semilunar valves

Question 7

Where is the pericardium and what is its function?

Answer 7

Layer filled with fluid outside the epicardium that lets the heart slip around.

Question 8

Do arteries or veins have the most pressure?

Answer 8

Arteries

Question 9

What happens when the Aortic valve snaps shut?

Answer 9

The pressure decreases allowing flow back into the heart and prevents back flow. The snap causes a dicrotic notch.

Question 10

How does de-oxygenated blood flow into the right atrium from the upper body, lower body and heart muscle?

Answer 10

Via the superior vena cava, inferior vena cava and coronary sinus.

Question 11

What happens when the blood reaches the lungs? how does it get there?

Answer 11

Right atrium-> Right Ventricle-> Lungs via pulmonary artery. Gaseous exchange= Oxygenation and removal of Carbon dioxide .

Question 12

Where does the oxygenated blood flow from the lungs/how?

Answer 12

To the left atrium via 4 pulmonary veins.

Question 13

Where does oxygenated blood travel after it reaches the left atrium?

Answer 13

Left atrium -> Left ventricle-> Body via aorta.

Question 14

Where is the sinoatrial node and what does it do?

Answer 14

Rear wall of atrium. AKA pacemaker- regular electrical discharge begins firing pattern of whole heart- brings heart to about 120bpm.

Question 15

Where is the beginning of firing pattern for the whole heart seen on an ECG?

Answer 15

The P wave shows beginning contraction pushing blood to ventricles.

Question 16

What/Where is the atrioventricular node? Where can you see it working on an ECG?

Answer 16

in wall between rich atrium and ventricle. Electrical discharge passes via AV bundle incl purkinje fibres to ventricles. Begins QRS complex.

Question 17

What is the process of the QRS waves?

Answer 17

Q wave (atrium systole)-> ventricular contraction begins->R wave (atrium distole)-> S wave (ventricular excitation)

Question 18

What happens at the T wave?

Answer 18

depolarisation of ventricles -> beginning of ventricular diastole (U)

Question 19

Where does the heart receive external innervation?

Answer 19

Parasympathetic and sympathetic NS.

Question 20

What is the SNS transmitter? How does the SNS innervate the heart?

Answer 20

Acetylcholine. Vagal inhibition of SA node (reduces HR to approx 70bpm), Vagal withdrawal increase HR

Question 21

What is the PNS transmitter? How does the PNS innervate the heart?

Answer 21

norepinephrine. increase in rate of SA node discharge and increase excitability of cardiac tissue both increase HR output.

Question 22

What does the baroreceptor reflex control? where are the baroreceptors?

Answer 22

Control HR-BP links. receptors in carotid sinus in neck

Question 23

What is the RSA?

Answer 23

Respiratory sinus arrhythmia. natural cycle of arrhythmia that occurs though influence of breathing on flow of sympathetic and vagal impulses to sinoatrial node. HR variability in synchrony with respiration.