Brainscape's Knowledge GenomeTM

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


See full index

BRS - Cardio > Control of Heart Function > Flashcards

Control of Heart Function Flashcards

1
Q

What 3 sources control function of the heart?

A
  • CNS
  • kidneys
  • blood vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What parts of the ANS control the heart?

A

cardio-regulatory centre + vasomotor centres in medulla + Vagus nerve

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

How does the parasympathetic NS control heart rate?

A
  • rest + digest

* vagus nerve decreases HR by decreasing slope of phase 4

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

How does the sympathetic NS control heart rate?

A
  • fight or flight
  • cardiac nerves from lower cervical + upper thoracic ganglia increase HR by increasing slope of phase 4 + increasing force of contraction (which increases Ca2+ dynamics)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is chronotropy?

A

increase of heart rate

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

What is inotropy?

A

increase of force of contraction

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

How does the renal system control heart rate?

A
  • decreased glomerular filtration = increased Na+ excretion = increase in blood volume
  • increased renin secretion = increase in angiotensin-II production = vasoconstriction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are changes in blood volume detected by the blood vessels?

A

increase in blood volume is detected by venous volume receptors

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

How are changes in blood pressure detected by the blood vessels?

A

increase blood pressure is detected by arterial baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do large pulmonary vessels detect + communicate changes in volume?

A

volume sensors (also in atria + right ventricle) send signals through glossopharyngeal + vagus nerves

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

What do volume sensors do when there is a decrease in filling?

A

reduced baroreceptors firing + increased SNS activity

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

What do volume sensors do when there is distention?

A

increases baroreceptors firing + decreased SNS activity

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

What vessels are part of the arterial circuit?

A

aortic arch + carotid sinus + afferent arterioles of the kidneys

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

How are changes in pressure detected in the arterial circuit?

A

pressure sensors send signals through glossopharyngeal + vagus nerves

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

What do pressure sensors do when there is a decrease in pressure?

A

decreased baroreceptors firing + increased SNS activity

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

What do pressure sensors do when there is a increase in pressure?

A

increased baroreceptors firing + decreased SNS activity

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

What does the sympathetic nervous system do?

A

• Pre-ganglionic fibres use acetylcholine as their
neurotransmitter
• Post ganglionic neurotransmitter is noradrenaline
• SNS is important for controlling the circulation

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

What does the parasympathetic nervous system do?

A

• Pre- and post-ganglionic fibres use
acetylcholine as neurotransmitter
• Muscarinic (M2) and Nicotinic receptors
• PNS is important for controlling the heart rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is the vasomotor centre?

A

located bilaterally in reticular substance of medulla + lower 1/3 of pons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What effects do higher centres of the brain (e.g. hypothalamus) have on the vasomotor centre?

A

can exert powerful excitatory + inhibitory effects

21
Q

How are impulses transmitted to the blood vessels?

A

distally through the spinal chord (to almost all the blood vessels)

22
Q

What does the lateral portion of the vasomotor centre do?

A

controls heart activity by influencing heart rate + contractility

23
Q

What does the medial portion of the vasomotor centre do?

A

transmits signals via vagus nerve to heart - tends to decrease heart rate

24
Q

What 3 zones is the vasomotor centre split into?

A
  • Vasoconstrictor (pressor) area
  • Vasodilator (depressor) area
  • Cardio-regulatory inhibitory area
25
Q

What is the name of the network of nerves that supplies the heart?

A

cardiac plexus - receives contributions from right + left vagus nerve + sympathetic trunk

26
Q

What does the right vagus nerve primarily innervate?

A

SA node

27
Q

What does the left vagus nerve primarily innervate?

A

AV node

28
Q

What receptors does the heart have? What binds to them?

A

adrenoceptors or adrenergic receptors - binds to adrenergic agonists such as noradrenaline + epinephrine

29
Q

What receptors does the parasympathetic nervous system act on? How?

A

M2-receptors, causes inhibition of

ATP ➜ cAMP ➜ PKA

30
Q

What receptors does the sympathetic nervous system act on?

A

β1-receptors + β2-receptors, causes more

ATP ➜ cAMP ➜ PKA

31
Q

What happens when a β1-receptor is bound by a β1-agonist?

A
  • heart rate increases (positive chronotropy)
  • conduction velocity increases (positive dromotropy)
  • contractility increases (positive inotropy)
  • rate of myocyte relaxation increases (positive lusitropy)
32
Q

When do β2-receptors become functionally more important than β1-receptors? Why?

A

heart failure - β1-receptors become down-regulated

33
Q

What else can noradrenaline bind to? What is the effect?

A

α1-adrenoceptors found on myocytes to produce small

increases in inotropy

34
Q

What else can bind to the α + β receptors in the heart?

A

Circulating catecholamines (epinephrine) released by the adrenal medulla

35
Q

What happens when acetylcholine binds to M2 muscarinic receptors?

A
  • negative chronotropy and dromotropy in the heart

* negative inotropy and lusitropy in the atria

36
Q

How do the sympathetic nerve fibres affect the glomerulus + nephron tubule cells?

A

innervate the afferent + efferent arterioles

37
Q

What is the primary site of sympathetic activity in the renal system?

A

afferent arterioles

38
Q

What is the significance of α1-adrenoceptors in the renal system?

A

causes vasoconstriction = decreased glomerular filtration rate = decreased Na+ filtered

39
Q

What is the significance of β1-adrenoceptors in the renal system?

A

causes renin secretion = conversion of angiotensin I to angiotensin II = vasoconstriction

40
Q

What 4 factors is venous volume distribution affected by?

A
  • peripheral venous tone
  • gravity
  • skeletal muscle pump
  • breathing
41
Q

What does central venous pressure determine?

A

amount of blood flowing back to heart

42
Q

How does constriction affect veins?

A

reduces compliance + venous return

43
Q

What does constriction in arterioles determine?

A
  • Blood flow to downstream organs
  • Mean arterial blood pressure
  • Pattern of blood flow to organs
44
Q

What is meant by local mechanisms for blood flow regulation?

A

mechanisms from endothelial or muscle cells

45
Q

Why are local mechanisms for regulating blood flow important?

A

important for reflex local blood flow regulation within an organ

46
Q

What are 4 endothelium derived mediators?

A
  • Nitric oxide (NO): potent vasodilator, diffuses into vascular smooth muscle cells
  • Prostacylin: vasodilator that also has antiplatelet & anticoagulant effects
  • Thromboxane A2 (TXA2): vasoconstrictor that is also heavily synthesised in platelets
  • Endothelins (ET): vasoconstrictors generated from nucleus of endothelial cells
47
Q

What is meant by systemic mechanisms for blood flow regulation?

A

extrinsic to the smooth muscle, include the ANS & circulating hormones

48
Q

What are 5 non-endothelium derived mediators?

A

• Kinins: bind to receptors on endothelial cells & stimulate NO synthesis – vasodilator effects
• Atrial natriuretic peptide (ANP): secreted from the atria in response to stretch – vasodilator effects to
reduce BP
• Vasopressin (ADH): secreted from pituitary gland. Binds to V1 receptors on smooth muscle to cause
vasoconstriction
• Noradrenaline/Adrenaline: secreted from adrenal gland (& SNS); causes vasoconstriction
• Angiotensin II: potent vasoconstrictor from the renin-angiotensin-aldosterone axis. Also stimulates ADH
secretion

BRS - Cardio (15 decks)

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