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Block 3 > HRR: Receptors Of The Cardiovascular System > Flashcards

HRR: Receptors Of The Cardiovascular System Flashcards

1
Q

What are ionotropic agents?

A

Compounds that change intracellular calcium

Ionotropic agents influence the strength of heart muscle contractions.

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2
Q

What is the difference between positive and negative inotropes?

A

Positive inotropes increase contraction, while negative inotropes decrease contraction

This classification is based on their effect on the force of cardiac muscle contractions.

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3
Q

What are chronotropic agents?

A

Compounds with a direct influence on heart rate

Chronotropic agents can either increase or decrease heart rate.

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4
Q

What is the most numerous cell type in the heart?

A

Fibroblasts

Fibroblasts are crucial for the structural integrity of the heart.

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5
Q

What are the most voluminous cells in the heart?

A

Myocytes

Myocytes are responsible for the contractile function of the heart.

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6
Q

What is the function of endothelial cells in the heart?

A

They line blood vessels and the endocardium

Endothelial cells play a key role in vascular health and function.

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7
Q

What are pacemaker cells?

A

They allow for automaticity; they’re found in the SA and AV nodes

Pacemaker cells regulate the heart’s rhythm.

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8
Q

What are Purkinje fibers?

A

They’re part of the conduction system and utilize connexin 40 to communicate with each other and surrounding myocytes

Purkinje fibers facilitate rapid conduction of electrical impulses.

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9
Q

What kind of junction connects cardiomyocytes?

A

Gap junctions; this allows for coordinated contraction

Gap junctions enable electrical coupling between heart muscle cells.

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10
Q

Can cardiac muscle be tetanized?

A

No

Cardiac muscle’s inability to tetanize is crucial for its function and prevents prolonged contraction.

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11
Q

Where in the vasculature do we find adrenergic receptors?

A

Tunica media

Adrenergic receptors are involved in the regulation of vascular tone and blood pressure.

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12
Q

What is the relevant ion channel type in the heart?

A

Voltage-gated

Voltage-gated ion channels are crucial for generating action potentials in cardiac tissue.

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13
Q

What is an electrical sensor in an ion channel?

A

A transmembrane helix that responds to changes in charge of the membrane and changes the shape of the pore in the ion channel

These sensors enable the channel to open or close in response to voltage changes.

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14
Q

Where do we find baroreceptors, and what do they do?

A

The aortic arch and carotid bifurcation; they sense stretch

Baroreceptors play a key role in regulating blood pressure by detecting changes in vessel wall stretch.

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15
Q

Where do we find chemoreceptors, and what do they do?

A

In the carotid/aortic bodies; they monitor pH, CO2, O2 levels

Chemoreceptors are essential for respiratory and cardiovascular regulation.

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16
Q

What nerves are associated with baroreceptors and chemoreceptors?

A

Vagal and glossopharyngeal

These nerves transmit sensory information from baroreceptors and chemoreceptors to the central nervous system.

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17
Q

What areas of the heart are most innervated by the autonomic nervous system?

A

SA and AV nodes; innervation of the ventricles is sparse

The SA and AV nodes are crucial for regulating heart rate and rhythm.

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18
Q

What is the major adrenergic receptor in the heart?

A

B1

B1 receptors are primarily responsible for increasing heart rate and contractility.

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19
Q

What is the major adrenergic receptor in the vasculature?

A

Alpha (α)

Alpha receptors primarily mediate vasoconstriction in blood vessels.

20
Q

Describe the effects of epinephrine at low doses.

A

Prefers beta receptors; increases systolic BP, drops peripheral resistance, increases heart rate, overall increased cardiac output

Epinephrine’s action at low doses results in enhanced cardiac performance.

21
Q

Describe the effects of norepinephrine.

A

Prefers alpha receptors; increases SBP, peripheral resistance; initial heart rate bump followed by reflex bradycardia

Norepinephrine primarily causes vasoconstriction and a complex response in heart rate.

22
Q

Describe the effects of isoproterenol.

A

Impacts beta receptors; slightly increases SBP, large drop in peripheral resistance, increases heart rate, increases cardiac output

Isoproterenol is often used in clinical settings to manage bradycardia and heart block.

23
Q

What role does the sodium-potassium pump play in the heart?

A

It helps restore/determine resting membrane potential

The sodium-potassium pump is crucial for maintaining the electrochemical gradient across cardiac cell membranes.

24
Q

Describe digitalis toxicity.

A

Digitalis binds to the sodium-potassium pump, preventing sodium from leaving the cell, which increases contractility.

This condition also results in a negative chronotropic effect.

25
Q

What is the first step in the Renin-Angiotensin-Aldosterone System (RAAS)?

A

Renin from the kidney cleaves angiotensinogen to angiotensin I

This process initiates the RAAS cascade, which regulates blood pressure and fluid balance.

26
Q

What happens to angiotensin I in the lungs?

A

Angiotensin I is cleaved by ACE to produce angiotensin II

ACE stands for Angiotensin-Converting Enzyme, which plays a critical role in this conversion.

27
Q

What effect does angiotensin II have?

A

It exerts vasoactive effect through AT receptors coupled to Gq

Angiotensin II is a potent vasoconstrictor and plays a significant role in increasing blood pressure.

28
Q

What stimulates aldosterone release?

A

Angiotensin II stimulates aldosterone release

Aldosterone is crucial for sodium retention and potassium excretion in the kidneys.

29
Q

What do ACE inhibitors do?

A

They block the AT receptors that bind angiotensin II, allowing them to act as antihypertensives. This is because they’ll prevent the vasoconstriction action of angiotensin II and the release of aldosterone

ACE inhibitors are commonly used to treat high blood pressure and heart failure.

30
Q

What do aldosterone blockers do?

A

They act as diuretics

Aldosterone blockers help reduce fluid retention and lower blood pressure.

31
Q

What is endothelin-1?

A

It is a potent vasoconstrictor produced by the endothelium

Endothelin-1 plays a key role in regulating vascular tone and blood pressure.

32
Q

What is an Eta receptor?

A

Endothelin receptor that functions through Gq signaling

Eta receptors mediate the vasoconstrictive effects of endothelin-1.

33
Q

What is an Eith receptor?

A

Endothelin receptor involved in clearance

Eith receptors help regulate the levels of endothelin-1 in circulation.

34
Q

What are common effects of the muscarinic system in terms of the heart?

A

Vasodilation, decreased HR, decreased conduction, and decreased contractility

The muscarinic system is primarily mediated by acetylcholine.

35
Q

Describe the role of acetylcholine in the heart.

A

acetylcholine works with the parasympathetic nervous system and acts on/opens potassium channels via the Gi pathway, allowing potassium to leave the cell. This results in hyperpolarization and slows HR

36
Q

What neurotransmitter works with the parasympathetic nervous system and opens potassium channels?

A

Acetylcholine

Acetylcholine acts via the Gi pathway, allowing potassium to leave the cell, resulting in hyperpolarization and slowing heart rate.

37
Q

What is the primary function of the cGMP system in the heart?

A

Blocks the effects of Gq, associated with vasodilation, NO, and inactivating L-type Ca channels.

The cGMP system plays a significant role in cardiovascular regulation.

38
Q

What are natriuretic peptides?

A

Increase excretion of sodium and, as a result, water.

They play a crucial role in regulating blood volume and pressure.

39
Q

List some of the main natriuretic peptides.

A
  • ANP
  • BNP
  • CNP
  • DNP

These peptides are involved in the regulation of blood pressure and fluid balance.

40
Q

When are natriuretic peptides activated?

A

When the atrium senses stretch, releasing atrial natriuretic peptide.

This process helps to increase sodium and water excretion to reduce blood volume.

41
Q

Which natriuretic peptide is used as a marker for heart failure?

A

BNP

Brain Natriuretic Peptide (BNP) levels are often elevated in heart failure.

42
Q

What do VEGF receptors do when activated?

A

Increase vascularization.

Vascular Endothelial Growth Factor (VEGF) receptors are crucial for blood vessel formation.

43
Q

What is the role of vasopressin receptors?

A

They are anti-diuretic.

Vasopressin receptors help regulate water retention in the body.

44
Q

What is the function of thyroid receptor A?

A

Impacts heart rate and arrhythmia.

Thyroid hormones play a significant role in cardiac function.

45
Q

What is the function of thyroid receptor B?

A

Lipid modification.

Thyroid receptor B is involved in metabolic processes related to lipids.

46
Q

What does thyrotoxicosis lead to?

A
  • Increase in heart rate
  • Hypertension
  • Cardiac output
  • Oxygen demand
  • Can lead to high output heart failure

Thyrotoxicosis can have significant cardiovascular effects.

Block 3 (52 decks)

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