Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardiology > Special circulations > Flashcards

Special circulations Flashcards

1
Q

Where do left and right coronary arteries arise from?

A

base of the aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do most coronary veins drain into the atrium?

A

via coronary sinus into the right atrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What special adaptations to the circulation are in the coronary arteries?

A
  • high capillary density
  • high basal blood flow
  • high oxygen extraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does high oxygen extraction refer to?

A

Even under resting conditions, the heart muscle will extract most of the oxygen presented to it (75% compared to 25% whole body average)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is coronary blood flow controlled by?

A

intrinsic and extrinsic mechanisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the intrinsic mechanisms for low O2 levels?

A
  • low O2 causes vasodilation of the coronary arteries

- metabolites are released which act as vasodilators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the main metabolite responsible for vasodilation in the intrinsic mechanism?

A

adenosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the extrinsic mechanisms for low O2 levels?

A

sympathetic stimulation causing vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the body override the sympathetic stimulation?

A
  • sympathetic stimulation causes increased HR and SV.
  • This causes the heart to work harder
  • This leads to decreased O2
  • metabolites cause vasodilation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What part does adrenaline play in the extrinsic mechanism?

A

Sympathetic stimulation causes release of adrenaline which causes vasodilation. This helps to override the vasoconstriction further

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens to the blood flow in the left coronary artery during systole?

A

The blood flow becomes almost 0 due to the increased pressure caused by the contraction of the left ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens to the blood flow in the left coronary artery during diastole?

A

The blood flow is normal as there is less pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What affect would an increased HR have on oxygenation of the myocardium?

A

Increased HR leads to shortened diastole. Since most of the blood flow occurs in diastole this causes decreased coronary blood flow, therefore less oxygenation and therefore increased chest pain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to the blood flow in the right coronary artery during systole and diastole?

A

Right ventricular pressure is not as high as the left ventricular pressure. Therefore the constriction of the right coronary artery does not occur and the blood flow remains similar in both systole ad diastole.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What part of the brain is very sensitive to hypoxia?

A

grey matter- consciousness lost after few seconds of ischaemia, irreversible cell damage within ~ 3 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What two arteries form the circle of willis?

A

basilar and carotid arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is the circle of willis act as protection for the brain?

A

Major cerebral arteries arise from Circle of Willis

Cerebral perfusion should be maintained even if one carotid artery gets obstructed.

Nevertheless, obstruction of a smaller branch of a main artery would deprive a region of the brain of its blood supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What classifies as an ischemic stroke?

A

Atheroma or blood clot (embolus)

19
Q

What classifies as a Haemorrhage stroke?

A

damaged vessel wall

20
Q

What is the most common type of stroke?

A

ischemic

21
Q

What does a drop in MAP do to the arterioles in the brain?

A

causes vasodilation of the arterioles

22
Q

What does a rise in MAP do to the arterioles in the brain?

A

causes vasoconstriction of the arterioles

23
Q

What is autoregulation?

A

AUTOREGULATION of cerebral blood flow guards against changes in cerebral blood flow

24
Q

What effect does sympathetic stimulation have on cerebral blood flow?

A

very little

25
Q

Is there baroreceptor reflex in the brain

A

no

26
Q

What are the limits for autoregualtion?

A

Autoregulation fails if MABP falls below ~ 60mmHg

or rise above ~ 160mmHg

27
Q

What occurs in a MABP below 50mmHg?

A

confusion, fainting, and brain damage if not quickly corrected

28
Q

What dies increased partial pressure of CO2 cause?

A

vasodilation

29
Q

What does decreased partial pressure of carbon dioxide cause?

A

vasoconstriction

30
Q

What does hyperventilating do?

A

By hyperventilating, remove a lot of CO2 causing vasoconstriction thereby reducing blood flow to brain which can lead to fainting

31
Q

Where does blood flow to in the brain?

A

Active parts of the brain

32
Q

What are the components of the skull?

A

brain (80%)
blood (12%)
cerebrospinal fluid (8%)

33
Q

What is the normal intracranial pressure in the skull?

A

8-13 mm Hg

34
Q

What is the equation for Cerebral perfusion pressure?

A

Cerebral Perfusion Pressure (CPP) = Mean Arterial Pressure (MAP) - ICP

35
Q

What will increasing the intracranial pressure do?

A

will decrease blood flow ie cerebral perfusion pressure

36
Q

What is the blood brain barrier?

A

cerebral capillaries with very tight intracellular junctions. These capillaries are very permeable to O2 and CO2 but not to ions

37
Q

How does glucose pass the blood brain barrier?

A

By facilitated diffusion using specific carrier molecules

38
Q

What is the nature of the pulmonary artery BP?

A

low, typically (20-25)/(6-12) mmHg

39
Q

What affect does hypoxia have on pulmonary arteries?

A

Hypoxia causes vasoconstriction in pulmonary arteries so that blood gets diverted from poorly ventilated areas into the non-damaged areas.

40
Q

Why do absorptive forces exceed filtration forces in pulmonary circulation?

A

protects against pulmonary oedema

41
Q

Why does skeletal muscle blood flow increase during exercise?

A
  • metabolites cause vasodilation
  • adrenaline causes vasodilation
  • increased CO
42
Q

How does the skeletal muscle pump work?

A

contraction of muscles causes blood in veins to be pumped up which aids in venous return

The pump reduces the chance of postural hypotension and fainting

43
Q

What are varicose veins?

A

Blood pools in lower limb veins if venous valves become incompetent

44
Q

Why does varicose veins not lead to reduction of CO?

A

because of chronic compensatory increase in blood volume

Cardiology (32 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions