cardiac output and lung disease

Question 1

What is the definition of cardiac output?

Answer 1

the volume of blood pumped by one ventricle of the heart in one minute

Question 2

What are the two factors of cardiac output?

Answer 2

• the heart rate (the rate at which the heart beats)
• the stroke volume (volume of blood pumped out at each beat)

Question 3

What is the equation for the cardiac output?

Answer 3

heart rate x stroke volume

Question 4

How do valves prevent the backflow of blood?

Answer 4

• they only open one way
• if there is higher pressure behind a valve, its forced open
• if there is higher pressure in front of the valve its forced shut

Question 5

What is the role of atria- ventricular valves and when do they open and close?

Answer 5

stops blood flowing back into the atria when the ventricles contract

Open = pressure in atria greater then pressure in ventricles

Closed = pressure in ventricles greater then pressure in atria

Question 6

What is the role of semi-lunar valves and when do they open and close?

Answer 6

stops blood in the arteries flowing back into the ventricles when the ventricles contract

Open = pressure in ventricles greater then pressure in arteries,

Closed = pressure in arteries greater then pressure in ventricles

Question 7

What are pocket valves?

Answer 7

valves in the veins

Question 8

What is the blood supply for the liver called? What is the blood supply for the kidneys called?

Answer 8

liver = hepatic

kidneys =renal

Question 9

What are bundle of His?

Answer 9

the fibres in the muscle separating the right and left ventricle

Question 10

label where the atriaventrical node and the sino atrial node are on the heart

Answer 10

Question 11

Explain this graph for A:

Answer 11

ventricles are contracting (and AV valves are shut because there is a lower pressure in the atrium than the ventricles) forcing blood into the aorta

Question 12

Explain the graph for C (this includes everything from the huge peak to the end of graph):

Answer 12

pressure rises dramatically as the thick muscular walls of the ventricule contract.

Pressure falls as the ventricles empty and the walls relax

As diastole occurs, blood starts filling the atria, some passively enters the ventricle. The AV valve closes when the light blue line falls below the green (pressure in atria > ventricle)

Question 13

Why is the pressure for the atrium always low?

Answer 13

Because they have thin walls

Question 14

Which feature of the aorta allows it to maintain a high pressure?

Answer 14

elasticity of its walls = this creates a recoil action which keeps pressure high

Question 15

Name the 3 stages of a cardiovascular disease

Answer 15

1. Atheroma Formation
2. Atheroma = Aneurysm and Thrombosis
3. Interrupted Blood Flow to Heart = Myocardial Infarction

Question 16

Describe how atheroma forms

Answer 16

1. Damage to endothelium of artery (e.g. by high blood pressure) = WBCs (mostly macrophages) and lipids from blood clump together under lining = form fatty streaks
2. Overtime, WBCs, lipids and connective tissue build up & harden to form fibrous plaque called atheroma

Question 17

What can the plaque (atheroma) do and cause?

Answer 17

Plaque blocks lumen of artery & restricts blood flow → causes blood pressure to increase

Question 18

Name the 2 types of disease that affects arteries

Answer 18

1. Aneurysm
2. Thrombosis

Question 19

What is aneurysm? Describe how it occurs

Answer 19

Balloon-like swelling of artery

1. Atheroma plaques damage and weakens arteries
   - Narrow arteries = ↑ blood pressure
2. ## When blood travels through weakened artery at high pressure = pushes inner layers of artery though outer elastic layer to form balloon-like swelling = aneurysm

Question 20

What may happen to an aneurysm?

Answer 20

burst and cause haemorrhage (bleeding)

Question 21

What is thrombosis? Describe how it occurs

Answer 21

Formation of blood clot

1. Atheroma plaque can burst through endothelium of artery
2. Damages artery wall & leaves rough surface
3. ## Platelets and fibrin accumulate at site of damage & form blood clot (thrombus)

Question 22

What can the blood clot do & what can this lead to?

(thrombosis)

Answer 22

• Blood clot can cause complete blockage of artery or can become dislodged & block blood vessel elsewhere
• Debris from rupture can cause another blood clot to form further down artery