L7 physiology
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Questions and Answers

What primarily contributes to an increase in blood pressure?

  • Decreased peripheral vascular resistance
  • Lowered cardiac output
  • Decreased elasticity of vessel walls (correct)
  • Reduced volume of blood

Which mechanism is involved in the short-term regulation of blood pressure?

  • Natriuretic peptides
  • Baroreceptor reflex (correct)
  • Vascular remodeling
  • Renin-angiotensin-aldosterone system

Which factor is not considered a determinant of blood pressure?

  • Volume of blood
  • Viscosity of blood
  • Dietary habits (correct)
  • Rigidity of vessel walls

Long-term regulation of blood pressure primarily involves which system?

<p>Hormonal control via the renal system (D)</p> Signup and view all the answers

Which of the following is a common risk factor for developing high blood pressure?

<p>Age (C)</p> Signup and view all the answers

In the context of blood pressure, what is peripheral vascular resistance mainly affected by?

<p>Viscosity of blood (D)</p> Signup and view all the answers

What does the cardio-inhibitory center primarily regulate?

<p>Heart rate (C)</p> Signup and view all the answers

What physiological effect does increased blood pressure generally have on vessel walls?

<p>Causes vessel wall damage over time (A)</p> Signup and view all the answers

What is the role of renin in the Renin-Angiotensin System?

<p>It triggers sodium reabsorption in the kidneys. (A)</p> Signup and view all the answers

How does the Renin-Angiotensin System affect renal arterioles?

<p>It constricts renal arterioles, diminishing blood flow to the kidneys. (B)</p> Signup and view all the answers

What triggers the release of renin in the kidneys?

<p>Low arterial pressure sensed by JG cells. (C)</p> Signup and view all the answers

What is the effect of aldosterone in the context of the Renin-Angiotensin System?

<p>It leads to an increase in sodium reabsorption capacity. (A)</p> Signup and view all the answers

What happens to pro-renin molecules when arterial pressure falls too low?

<p>They are split to release renin. (D)</p> Signup and view all the answers

How does the Renin-Angiotensin System influence salt and water retention?

<p>Through the promotion of osmotic reabsorption. (D)</p> Signup and view all the answers

What cells in the kidneys synthesize and store pro-renin?

<p>Juxtaglomerular cells. (A)</p> Signup and view all the answers

What is the impact on blood pressure when salt intake is decreased?

<p>Blood pressure decreases significantly. (C)</p> Signup and view all the answers

What defines blood pressure?

<p>The force exerted by circulating blood against blood vessel walls (B)</p> Signup and view all the answers

Which of the following is a key determinant of blood pressure?

<p>Cardiac output (C)</p> Signup and view all the answers

Which factor is least likely to affect blood pressure in the short term?

<p>Long-term dietary habits (D)</p> Signup and view all the answers

What is a primary mechanism for long-term regulation of blood pressure?

<p>Fluid balance maintained by the kidneys (D)</p> Signup and view all the answers

Normal blood pressure values for adults are generally considered to be:

<p>120/80 mmHg (B)</p> Signup and view all the answers

Flashcards

Blood Pressure

The pressure of blood against artery walls.

Determinants of Blood Pressure

Factors influencing blood pressure; include cardiac output, peripheral resistance, blood volume, blood viscosity, and vessel elasticity.

Cardiac Output (CO)

The amount of blood pumped by the heart per minute.

Peripheral Resistance (PR)

Opposition to blood flow in the arteries.

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Baroreceptor Reflex

Short-term blood pressure regulation mechanism involving sensors (baroreceptors) that detect pressure changes.

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Baroreceptors Location

Located in the carotid sinus and aortic arch, these receptors sense changes in blood pressure.

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Short-Term BP Regulation

BP regulation involving the nervous system, quick response to changes in pressure.

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Long-Term BP Regulation

BP regulation primarily influenced by the kidneys' control system and adjustments in blood volume.

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Renin-Angiotensin System

A system that regulates blood pressure by controlling sodium and water reabsorption in the kidneys.

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Pro-renin

An inactive form of renin, stored in the Juxtaglomerular cells of the kidneys.

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Juxtaglomerular cells (JG cells)

Specialized cells in the kidney that produce and release renin.

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Renin

An enzyme released by JG cells that starts the renin-angiotensin cascade.

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Low blood pressure

A condition where blood pressure is below the normal range.

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Angiotensinogen

A protein produced by the liver that renin converts into angiotensin I.

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Sodium reabsorption

The process of absorbing sodium from the kidney tubules back into the bloodstream .

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Aldosterone

A hormone from the adrenal glands that promotes sodium reabsorption.

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Blood Pressure (BP)

The force of blood pushing against the walls of your arteries as your heart pumps.

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Systolic BP

The maximum pressure in your arteries when your heart beats and pumps out blood.

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Diastolic BP

The minimum pressure in your arteries when your heart rests between beats.

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Factors Affecting BP

Anything that impacts the volume of blood being pumped (cardiac output) or the resistance to blood flow (peripheral resistance).

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Study Notes

Blood Pressure and Its Regulation

  • Blood pressure is the pressure of blood pushing against artery walls.
  • Normal blood pressure ranges vary.
  • Normal: Systolic <120 and Diastolic <80
  • Elevated: Systolic 120-129 and Diastolic <80
  • High Blood Pressure (Hypertension) Stage 1: Systolic 130-139 or Diastolic 80-89
  • High Blood Pressure (Hypertension) Stage 2: Systolic ≥ 140 or Diastolic ≥ 90
  • Hypertensive Crisis: Systolic ≥ 180 and/or Diastolic ≥ 120 (consult a doctor immediately).

Determinants of Blood Pressure

  • Blood pressure increases with:
    • Increased cardiac output
    • Peripheral vascular resistance
    • Volume of blood
    • Blood viscosity
    • Vessel wall rigidity
  • Blood pressure decreases with:
    • Decreased cardiac output
    • Decreased peripheral vascular resistance
    • Decreased blood volume
    • Decreased blood viscosity
    • Increased vessel wall elasticity

High Blood Pressure Causes and Risk Factors

  • Age (blood pressure usually increases with age)
  • Family history/genetics (high blood pressure often runs in families)
  • Lifestyle habits (diet, exercise, smoking, etc.)
  • Medications
  • Other medical conditions
  • Race/ethnicity
  • Sex
  • Social and economic factors

Regulation of Blood Pressure

  • Blood pressure (BP) regulation is done in two phases: acute/short-term and chronic/long-term.
  • Acute/short-term regulation is primarily controlled by reflexes, neural mechanisms, and controlled by the vasomotor center in the cardiovascular system. Specific centers like the cardiovascular inhibitory center and cardiovascular accelerator center are involved.
  • Chronic/long-term regulation depends mainly on the renal mechanism of the renin-angiotensin-aldosterone system.

Acute or Short-Term Regulation of Blood Pressure

  • Baroreceptor reflex (responds to changes in blood pressure)
    • Receptors located in carotid sinus and aortic arch
    • Afferent nerves transmit signals to the medulla oblongata
    • Medullary centers adjust cardio-inhibitory or cardio-acceleratory centers (controlling heart rate) and vasomotor center (influencing vessel diameter)
    • Efferent nerves regulate heart rate and vasodilation/vasoconstriction

Long-Term Regulation of Blood Pressure: Renin-Angiotensin System

  • Kidneys synthesize and store pro-renin, converted to renin when arterial pressure falls too low
  • Renin triggers the production of angiotensin II (leading to vasoconstriction) in the lungs.
  • Angiotensin II causes:
    • Renal retention of salt and water
    • Increased blood volume
    • Increased blood pressure
  • Renin-angiotensin system also affects aldosterone secretion, which further regulates salt and water balance affecting blood pressure long term.
  • Opposite changes occur when salt intake is decreased.

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Test your knowledge on blood pressure, its regulation, and the determinants that affect it. Understand normal ranges, stages of hypertension, and the causes and risk factors associated with high blood pressure. This quiz will help reinforce your understanding of cardiovascular health.

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