3.2 Transport In Animals (heart)

Question 1

How does blood enter the heart?

Answer 1

Via the Vena Cava

Question 2

What is thicker the left atrium or the left ventricle?

Answer 2

The ventricle because the blood is travelling a further distance

Question 3

What are the purpose of coronary arteries?

Answer 3

Supply cardiac muscle with oxygenated blood

Question 4

What is the purpose of the Septum?

Answer 4

Prevents oxygenated and deoxygenated blood mixing

Question 5

How does deoxygenated blood leave the heart?

Answer 5

Through the pulmonary artery

Question 6

How does deoxygenated blood leave the heart?

Answer 6

Pulmonary Artery

Question 7

How does oxygenated blood enter the heart?

Answer 7

The Pulmonary vein

Question 8

What are the two main types of valves?

Answer 8

The Atrioventricular and the semi lunar

Question 9

What is the definition of the cardiac cycle?

Answer 9

The sequence of events in one heart beat

Question 10

What order does the cardiac cycle occur?

Answer 10

Filling phase (diastole)
Atrial contraction
Ventricular contraction

Question 11

What are the features of the filling phase (diastole)?

Answer 11

Atria and ventricles are relaxed
Blood enters via pulmonary vein and Vena Cava
SL valves are closed
AV valves open
Blood flows passively from atria to ventricles

Question 12

What happens if valves don’t work properly?

Answer 12

There’s a back flow of blood

Question 13

What causes the AV valves to open?

Answer 13

Relaxed muscles create a higher pressure in atria than ventricles

Question 14

What causes AV valves to close?

Answer 14

Ventricles contracting create a higher pressure in the ventricles than the atria

Question 15

What sound do the AV valves make?

Answer 15

‘Lub’

Question 16

What causes SL valves to open?

Answer 16

Ventricles contract increasing pressure in ventricles in comparison to aorta

Question 17

What causes SL Valves to close?

Answer 17

Ventricles relax decreasing pressure in comparison

Question 18

What sound do the semi-lunar valves make?

Answer 18

‘Dub’

Question 19

What is the sino-atrial node and what is its role?

Answer 19

• Located in right atrium
  Group of cells that can initiate their own impulse

Question 20

How is cardiac muscle myogenic?

Answer 20

It can initiate its own contraction

Question 21

What is the order of the electrical activity bringing about the cardiac cycle?

Answer 21

1. Electrical activity from SAN spreads across both atria (brings about atrial systole)
2. Atrioventricular septum blocks impulse but can pass via avn
   3.Short delay
3. AVN conducts electricity down to the base of the ventricles (ensures atria finish contracting)
4. Electrical activity travels to base of ventricles via bundle of His
5. Electrical activities spread across the surface via purkyne fibres
   7.Ventricles contract from the base upward

Question 22

What is an electrocardiogram?

Answer 22

The reading of a single heartbeat

Question 23

What do the features of an ECG mean?

Answer 23

Small bump at the start- Atrial systole
Small dip then big increase and dip again- Ventricular systole
Small bump at the end- Diastole

Question 24

What is tachycardia?

Answer 24

Heart rate over 100 bpm

Question 25

What is bradycardia?

Answer 25

Heart rate below 60 bpm

Question 26

What is an ectopic heart beat?

Answer 26

Extra heart beats out of normal rhythm

Question 27

What is atrial fibrillation?

Answer 27

The atria contract very fast but not properly and ventricles contract less often

Question 28

What are the features of atrial systole?

Answer 28

Atria contract simultaneously
Forces remaining blood from atria into ventricles
AV valves close

Question 29

What are the features of ventricular systole?

Answer 29

AV and SL valves closed
Ventricles contract from base upwards
Blood forced out of aorta and pulmonary artery
SL valves open

Question 30

What is a double circulatory system?

Answer 30

• Two separate circuits
• Blood passes through heart twice
• Second circuit is between heart and lungs (pulmonary circulation)