Cardiovascular Physiology and Pharmacology Quiz

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Questions and Answers

What is the primary mechanism through which MLCK contributes to smooth muscle contraction?

It inhibits myosin phosphorylation.

It phosphorylates myosin light chains. (correct)

It generates cAMP.

It activates phospholipase C.

Which adrenergic receptor type is associated with vasodilation when adrenaline binds to it?

α1 adrenergic receptor

β2 adrenergic receptor (correct)

α2 adrenergic receptor

β1 adrenergic receptor

What is the primary condition caused by a plaque projecting into the lumen of an artery?

Decreased blood flow (correct)

Increased blood flow

Enhanced vessel elasticity

Increased oxygen supply

What effect does noradrenaline have on the heart when it binds to β1 receptors?

It increases the Phase 4 slope. Signup and view all the answers

What type of event might occur as a result of plaque rupture?

Embolism Signup and view all the answers

Which of the following statements about adrenaline is incorrect?

It promotes contraction in smooth muscle cells. Signup and view all the answers

Katherine experiences angina during mild exertion. This happens because:

Blood supply is less than demand Signup and view all the answers

What does angioplasty involve?

Opening a narrowed vessel Signup and view all the answers

What is the role of cAMP in the mechanism of vasodilation induced by adrenaline?

It leads to the inhibition of MLCK. Signup and view all the answers

Which of the following does not typically contribute to vasodilation?

Increased intracellular calcium concentration. Signup and view all the answers

What is a common symptom experienced by individuals with narrowed coronary arteries, particularly during stress?

Chest pain Signup and view all the answers

Which protein is activated by phospholipase C in the context of arteriolar control?

Protein Kinase C Signup and view all the answers

In terms of procedural outcomes, which of the following is a difference between PCI and CABG?

CABG typically requires longer recovery time Signup and view all the answers

What effect does acetylcholine have on the phase 4 slope of nodal cells?

It decreases the slope leading to lower heart rates. Signup and view all the answers

What is the primary physiological mechanism affecting Katherine when her coronary artery blood supply is insufficient?

Ischemia Signup and view all the answers

What happens to the rates of PCI and CABG from 1994 to 2005 in British Columbia?

PCI increased while CABG decreased Signup and view all the answers

What is the main result of insufficient blood supply to the cardiac muscle?

Chest pain known as Angina Signup and view all the answers

Which peptide hormone is primarily produced by the heart?

Atrial Natriuretic Peptide (ANP) Signup and view all the answers

Which metabolic factors are known to cause local vasodilation?

Increased adenosine and increased K+ Signup and view all the answers

What triggers the regional cerebral blood flow linked to?

Brain activity Signup and view all the answers

What physiological change occurs during systole in relation to coronary blood flow?

Coronary blood flow diminishes Signup and view all the answers

What might cause an older woman, like Katherine, to experience symptoms of chest pain upon exertion?

Coronary artery narrowing Signup and view all the answers

What happens to coronary blood flow during exertion?

It equals heart muscle demand Signup and view all the answers

Which mechanism is responsible for metabolic regulation of blood flow?

Tissue metabolites released by active cells Signup and view all the answers

What are the three layers of blood vessels consistent with arteries and arterioles?

Intima, media, adventitia Signup and view all the answers

Which of the following factors can affect arteriolar diameter?

Neural input, humoral factors, and tissue metabolites Signup and view all the answers

What is the primary role of arterioles in the cardiovascular system?

Regulating systemic vascular resistance (SVR) Signup and view all the answers

How do noradrenaline and adrenaline primarily affect vascular smooth muscle?

Promote vasoconstriction, thereby increasing blood pressure Signup and view all the answers

What distinguishes the regulation of coronary and cerebral blood flow from that of peripheral arterial blood flow?

Coronary and cerebral blood flow are always prioritized over other areas. Signup and view all the answers

What causes chest pain during angina?

Decreased oxygen supply to the heart muscle Signup and view all the answers

What does systemic vascular resistance (SVR) primarily depend on?

Volume of blood and arteriolar diameter Signup and view all the answers

At rest, how are arterioles generally characterized?

Partially constricted, maintaining some tone Signup and view all the answers

Study Notes

Blood Vessels - Topic 3

Objectives: This topic covers the three layers of arteries/arterioles, factors affecting arteriolar diameter (neural, hormonal, tissue metabolites), the actions of noradrenaline and adrenaline on smooth muscle, the differences in coronary/cerebral vs peripheral blood flow regulation, and the cause of chest pain (angina).

Mimi Case (Katherine)

Symptoms: While waiting for a bus, an older woman suddenly clutches her chest, sinks to her knees, appears terrified, is sweating (diaphoretic), short of breath (dyspneic), and has a fast heartbeat (tachycardic).

Basic Vessel Architecture

Lumen: The central space within a blood vessel where blood/fluid flows.
Intima: Primarily the endothelium.
Media: Smooth muscle and elastic tissue.
Adventitia: Connective tissue and fat.

Arterioles

Vasoconstriction and Vasodilation: Arterioles, also known as resistance vessels, use smooth muscle to regulate blood flow.
Blood Pressure Control: They play a crucial role in regulating blood pressure.

Maintaining Blood Pressure

Blood Flow Regulation: Blood pressure is controlled by both the volume of blood in arterioles and the state of contraction/relaxation (constriction/dilation) of the arterioles.
Systemic Vascular Resistance (SVR): The term used for the combined effect of arteriolar constriction/dilation on blood pressure.

Arterioles (Continued)

At Rest: Arterioles are partially constricted.
Blood Flow Determinants: Nerve impulses and hormones determine blood flow regulation.
Blood Pressure Control: These vessels demonstrate flexibility in blood pressure control.

What Determines Vasoconstriction and Vasodilation?

SNS (Sympathetic Nervous System): Releases noradrenaline and adrenaline.
PSNS (Parasympathetic Nervous System): Has insignificant role in vasoconstriction/dilation.

Noradrenaline and Smooth Muscle

Mechanism of Contraction: Noradrenaline causes vasoconstriction by activating alpha receptors. The process involves DAG, IP3, PK-C, calcium release and activation of the MLC kinase enzyme.

Adrenaline and Smooth Muscle

Mechanism of Vasodilation: Adrenaline causes vasodilation by acting on beta-2 receptors and activating cyclic AMP (cAMP), the protein kinase A (PKA) signaling pathway, leading to inhibition of MLC kinase.

Other Molecules Involved

Gs and Gq: GTP-binding proteins involved in the stimulation of smooth muscle.
PIP2: Phosphatidylinositol 4,5-bisphosphate.
B2 receptors: Adrenaline receptors involved in stimulating vasodilation.
AC: Adenylyl Cyclase.
Epinephrine vs. Adrenaline: These are the same hormone, just different names.

Vasoactive Hormones

Constrictors: Angiotensin II (kidneys), Arginine Vasopressin (brain).
Dilator: Atrial Natriuretic Peptide (ANP) (heart).

Tissue Metabolites

Regulation of Blood Flow: Active cells release tissue metabolites (e.g., oxygen, carbon dioxide, adenosine, potassium) causing local vasodilation.
Metabolic Regulation: This influences blood flow.

Coronary Circulation

Metabolic Regulation: Coronary blood flow regulation involves metabolic factors.
Coronary Blood Flow (BF): Reduced in systole (contraction phase).
Left Ventricle vs. Right Ventricle: More significant coronary flow in the left ventricle.

Ensuring Oxygen Supply

Heart Function: A continuous supply of oxygen to cardiac muscles is essential for proper function.

Insufficient Blood Supply

Causes of Chest Pain: Coronary artery spasm, narrowing due to plaque formation.
Angina: Chest pain due to insufficient blood supply to the heart.
Ischemia: Reduced blood flow resulting in oxygen deficiency in a tissue.

Cerebral Circulation

Metabolic Regulation: Cerebral blood flow is highly responsive to low oxygen tension.
Regional BF: The regional flow of blood related to brain activity.

Case of Katherine (continued) and Implications for Blood Vessels

Problem Correlation: Katherine's condition is related to insufficient coronary blood flow during exertion.
Balance of Supply and Demand: At rest, blood supply equals demand (no pain), but during mild exertion, supply falls short of demand (angina = chest pain).
Plaque Genesis: Plaque is formed in the artery intima with cholesterol and related fibrous materials.

Diagnostic Procedures

Stress Test: A test to evaluate heart function during exertion.
Angioplasty (PCI): To open narrow blood vessels.
CABG: To re-route the flow around blockages.

Case Study Conclusion

Summary: The case correlates blood vessel health, physiological mechanisms, and symptoms. Relevant diagnostic procedures and potential treatments are explained.

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Description

Test your knowledge on cardiovascular physiology, specifically focusing on smooth muscle contraction, adrenergic receptors, and the effects of adrenaline. This quiz will cover mechanisms of vasodilation, angina, and procedural interventions like angioplasty. Perfect for anyone studying cardiovascular system functions and pharmacological treatments.