Blood circuit and the heart L7

Question 1

What is the daily output of blood?

Answer 1

7000 litres

Question 1

How many muscular pumps does the human heart have?

Answer 1

Two

Question 2

What is the consequence of stoppage of blood pump?

Answer 2

Unconsciousness in 10 seconds and death in 4 minutes.

Question 3

How heavy is the heart?

Answer 3

300 grams

Question 4

Structure of the valves

Answer 4

Soft and pilant (flexible) yet tough enough to withstand 100,000 closures per day for 70-80 years.

Question 5

Which circuit is larger?

Answer 5

Systemic

Question 6

What is the ratio of blood found in pulmonary and systemic circuit?

Answer 6

9%/84%

Question 7

What is the resistance of the systemic circuit?

Answer 7

High because it is much larger - has way more volume

Question 8

What kind of pressure do we need in the systemic circuit and why?

Answer 8

High pressure to drive the blood through the circuit as it has got more volume to move

Question 9

What about the resistance and pressure of the pulmonary circuit?

Answer 9

Medium resistance

Question 10

Arteries

Answer 10

High pressure vessels that take blood away from the pumps

Question 11

Veins

Answer 11

Low pressure vessels that take blood towards the pumps

Question 12

What is the name for the connecting vessel that goes from the gut to the liver?

Answer 12

The hepatic portal veins - transport nutrients

Question 13

Is building a ventricular pump active or passive?

Answer 13

Passive

Question 14

What happens during the filling phase?

Answer 14

Here the ventricle is represented as a box with thick
muscular walls. There is a venous inlet on the left side
and an arterial outlet on the right. While the ventricle is
filling (from the venous end) an outlet valve is essential
to prevent arterial blood from returning to the pump.

Question 15

Ejection phase

Answer 15

An inlet valve is necessary to prevent high-pressure
blood in the pumping chamber from returning to the veins.

Question 16

What is an improvement that can be done to the ventricular pump?

Answer 16

An atrium is a reservoir upstream of the pump. During
the ejection phase (when the inlet valve is closed) the
atrium accumulates venous blood. This blood can enter
the ventricle quickly during the filling phase.

Question 17

What is another improvement?

Answer 17

f the inlet and outlet of the pump are moved to lie close
together, then the walls of the pumping chamber can
shorten in length as well as in width.
Adding an ‘appendage’ (also known as the auricle) which increases the
capacity of the atrium.

Question 18

Structure of the heart

Answer 18

Question 19

Peak pressures

Answer 19

Left Ventricle: 120mmHg
Right Ventricle: 27mmHg
Left Atrium: 8mmHg
Right Atrium: 5mmHg

Question 20

Cross sections through the heart walls

Answer 20

Question 21

Process of oxygenated and deoxygenated blood through the heart

Answer 21

Question 22

Inlet valves

Answer 22

Semilunar - tricuspid, mitral/bicuspid

Question 23

Outlet valves

Answer 23

Atrioventricular - pulmonary/aortic

Question 24

Venous drainage

Answer 24

Process which deoxygenated blood is carried away from an organ and returned to the heart (first delivered to the liver via the heptic portal vein)

Question 25

Diastole

Answer 25

Phase of the cardiac cycle when the heart relaxes after contraction

Question 26

Mid-systole

Answer 26

When the heart contracts

Question 27

What are the free edges of each flap tethered by?

Answer 27

Tendinous cords - which help prevent it from bursting upwards into the atrium during systole (contraction of heart)

Question 28

Is the valve opened or closed?

Answer 28

Opened

Question 29

Is the valve opened or closed?

Answer 29

Closed

Question 30

Wall thickness

Answer 30

Left Ventricle: Thick Right Ventricle: Medium Left Atrium: Thin Right Atrium: Thin

Question 31

Ox/Deox blood?

Answer 31

Left Ventricle: Ox Right Ventricle: Deox Left Atrium: Ox Right Atrium: Deox

Question 32

What happens to the outlet (pulmonary/aortic) valves during ventricular filling?

Answer 32

The outlet valves are closed as the pressure in the arteries is higher than that of the ventricles. Once the pressure in the ventricle chambers is greater than the pressure in the arteries, these valves are forced open, and ejection of blood occurs.

Question 33

Structure of the heart (use the diagram on medsci manual)

Answer 33