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Questions and Answers
What is the primary effect of pulmonary hypoxia on the pulmonary blood vessels?
What is the primary effect of pulmonary hypoxia on the pulmonary blood vessels?
How does the sympathetic nervous system primarily cause vasoconstriction?
How does the sympathetic nervous system primarily cause vasoconstriction?
What is the role of the baroreceptor reflex in maintaining blood pressure?
What is the role of the baroreceptor reflex in maintaining blood pressure?
Where are arterial chemoreceptors primarily located?
Where are arterial chemoreceptors primarily located?
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What type of capillaries allows for the passage of blood cells due to large gaps?
What type of capillaries allows for the passage of blood cells due to large gaps?
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Which mechanism involves sensors detecting changes to maintain homeostasis?
Which mechanism involves sensors detecting changes to maintain homeostasis?
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What role do veno-atrial receptors play in the cardiovascular system?
What role do veno-atrial receptors play in the cardiovascular system?
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What is the mechanism through which water passes across the capillary wall?
What is the mechanism through which water passes across the capillary wall?
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What response occurs due to low oxygen levels in the environment at high altitudes?
What response occurs due to low oxygen levels in the environment at high altitudes?
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What is the primary effect of adrenaline binding to beta-adrenoreceptors in the vascular system?
What is the primary effect of adrenaline binding to beta-adrenoreceptors in the vascular system?
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What physiological changes occur in anticipation of exercise?
What physiological changes occur in anticipation of exercise?
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What is the role of arterio-venous anastomoses in acral skin?
What is the role of arterio-venous anastomoses in acral skin?
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Which area of the body contains acral skin?
Which area of the body contains acral skin?
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How does the cerebral cortex influence autonomic responses during exercise?
How does the cerebral cortex influence autonomic responses during exercise?
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What mechanism contributes to heat loss in acral areas of the body?
What mechanism contributes to heat loss in acral areas of the body?
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What causes edema in the interstitium?
What causes edema in the interstitium?
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Which forces contribute to the movement of water across capillary walls?
Which forces contribute to the movement of water across capillary walls?
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What relationship does Fick's Law of Diffusion describe?
What relationship does Fick's Law of Diffusion describe?
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During dynamic exercise, what happens to systolic blood pressure?
During dynamic exercise, what happens to systolic blood pressure?
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What happens to venous blood distribution when standing up from a supine position?
What happens to venous blood distribution when standing up from a supine position?
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Which factor affects arterial pressure throughout the day?
Which factor affects arterial pressure throughout the day?
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What occurs to blood flow during static exercise, such as a prolonged handgrip?
What occurs to blood flow during static exercise, such as a prolonged handgrip?
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What is the primary function of the lymphatic system in relation to fluid balance?
What is the primary function of the lymphatic system in relation to fluid balance?
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Which factor directly increases the flow rate in a blood vessel according to Darcy's Law?
Which factor directly increases the flow rate in a blood vessel according to Darcy's Law?
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What is the primary effect of vasodilation on a blood vessel?
What is the primary effect of vasodilation on a blood vessel?
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What happens during the myogenic response when arterial pressure initially increases?
What happens during the myogenic response when arterial pressure initially increases?
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What primarily characterizes the compliance of blood vessels?
What primarily characterizes the compliance of blood vessels?
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What mechanism is primarily involved in the active hyperemia response?
What mechanism is primarily involved in the active hyperemia response?
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Which statement accurately describes post-exercise hyperemia?
Which statement accurately describes post-exercise hyperemia?
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What is the role of calcium ions ($Ca^{2+}$) in the myogenic response?
What is the role of calcium ions ($Ca^{2+}$) in the myogenic response?
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What primarily differentiates intrinsic and extrinsic blood flow control mechanisms?
What primarily differentiates intrinsic and extrinsic blood flow control mechanisms?
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What triggers the contraction of heart muscle cells during the plateau phase of the ventricular action potential?
What triggers the contraction of heart muscle cells during the plateau phase of the ventricular action potential?
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Which phase of the cardiac cycle corresponds to the isovolumetric contraction of the ventricles?
Which phase of the cardiac cycle corresponds to the isovolumetric contraction of the ventricles?
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What is represented by the QRS interval in an ECG?
What is represented by the QRS interval in an ECG?
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Which of the following best describes the function of the SA node in the cardiac conduction system?
Which of the following best describes the function of the SA node in the cardiac conduction system?
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What occurs during Phase 4 of the ventricular action potential?
What occurs during Phase 4 of the ventricular action potential?
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During which phase of the cardiac cycle does the aortic valve close?
During which phase of the cardiac cycle does the aortic valve close?
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What is the significance of the refractory period established during the plateau phase?
What is the significance of the refractory period established during the plateau phase?
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What does the PR interval in an ECG represent?
What does the PR interval in an ECG represent?
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During which phase of the cardiac cycle does the mitral valve open, leading to passive filling of the ventricles?
During which phase of the cardiac cycle does the mitral valve open, leading to passive filling of the ventricles?
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What characterizes the compliance of large elastic arteries such as the aorta?
What characterizes the compliance of large elastic arteries such as the aorta?
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How does an increase in right atrial pressure affect the energy of cardiac muscle contraction following Starling's law?
How does an increase in right atrial pressure affect the energy of cardiac muscle contraction following Starling's law?
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Which type of blood vessel acts as the primary site for gas exchange due to its structure?
Which type of blood vessel acts as the primary site for gas exchange due to its structure?
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What occurs during the ejection phase of the cardiac cycle?
What occurs during the ejection phase of the cardiac cycle?
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What is the primary function of the sinoatrial node in the human heart?
What is the primary function of the sinoatrial node in the human heart?
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Which of the following describes the correct relationship of cardiac output?
Which of the following describes the correct relationship of cardiac output?
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What occurs during diastole in the cardiac cycle?
What occurs during diastole in the cardiac cycle?
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Which of the following best defines end diastolic volume (EDV)?
Which of the following best defines end diastolic volume (EDV)?
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What effect does an increase in sympathetic activity have on heart rate?
What effect does an increase in sympathetic activity have on heart rate?
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Study Notes
Pulmonary Hypoxia (Low O₂)
- Causes vasoconstriction of pulmonary blood vessels
- Matching of air and blood flow is coordinated
- High altitudes lead to low oxygen in the air, causing short-term pulmonary vasoconstriction, directing blood to areas with higher oxygen levels and resulting in pulmonary hypertension.
- Process of coordinating the flow of air into the lungs with the flow of blood into the lungs.
Autonomic Regulation of Cardiovascular System
-
Sympathetic Nervous System (L-Sympathetic): Causes vasoconstriction by norepinephrine
- Norepinephrine binds to alpha-1 and alpha-2 adrenergic receptors on smooth muscle cells in blood vessels, increasing intracellular calcium which contracts smooth muscle.
- The short term response to a change in blood flow is vasoconstriction.
-
Parasympathetic Nervous System (Vasodilation): Mediated by Beta-adrenergic receptors.
- Adrenaline binds to beta-adrenergic receptors causing relaxation of vascular smooth muscles leading to vasodilation.
Negative Feedback Control
- Sensors detect changes
- Signal is propagated to the processor unit
- Effector mechanisms respond accordingly
- Maintaining homeostasis
Baroreceptor Reflex
- Mechanoreceptors that detect changes in blood pressure
- Located in the walls of the aortic arch and carotid arteries
- Increase in pressure stretches the vessel wall, detected by baroreceptors, sending signals to the medulla; reduces heart rate for lower blood pressure to set point.
- The signal is relayed to adjust/maintain blood pressure.
Veno-Atrial Receptors
- Detect changes in blood volume (low pressure)
- Located at the junction between veins and atria (in pulmonary artery)
- Helpful in cardiac-pulmonary responses
- Monitor blood volume and respond to low pressure conditions in veins
Arterial Chemoreceptors
- Detect oxygen, carbon dioxide, and pH levels.
- Responds to hypoxia (low oxygen) and hypercapnia (high carbon dioxide)
- Sending signals to the brainstem to increase sympathetic activity
- Detect changes in O2, CO2 and pH to the brainstem which relay into a sympathetic response
Capillaries
- Site for gas and metabolic exchange.
- Made of small arterioles and capillaries where metabolites and respiratory gases pass across the capillary wall via diffusion.
Continuous Capillary
- Most common type
- The entire capillary wall is composed of endothelial cells with no gaps.
Fenestrated Capillary
- Contains small gaps between endothelial cells.
- Found in places requiring rapid filtration, absorption, or secretion. (e.g. small intestine, endocrine glands, and glomerulus of the kidneys)
- Rapid filtration, absorption, or secretion
Discontinuous Capillary
- Have large gaps between endothelial cells.
- Blood cells can pass through the wall. (e.g. liver, spleen, and bone marrow)
- Blood cells and large proteins can pass through
- Water passes through capillaries by aquaporins (water channels) or endothelial gaps.
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Description
This quiz covers key concepts in pulmonary hypoxia and the autonomic regulation of the cardiovascular system. It examines the physiological responses to low oxygen levels and the roles of the sympathetic and parasympathetic nervous systems in regulating blood flow. Test your understanding of these critical processes and their implications on human health.
