Week 2 Flashcards
What is the innermost layer of blood vessels called?
Tunica Intima
Composed of simple squamous epithelium, termed endothelium.
What type of epithelium composes the Tunica Intima?
Simple squamous epithelium
Also known as endothelium.
What is the function of the Tunica Intima?
Regulates vascular tone via release of nitric oxide (NO) and endothelin
Controls inflammation, leukocyte adhesion, and vascular permeability.
What layer is primarily composed of smooth muscle cells?
Tunica Media
Arranged circularly around the vessel lumen.
What does the Tunica Media regulate?
Vasoconstriction and vasodilation
Influences blood pressure and flow.
What type of fibers does the Tunica Media contain?
Elastic fibers, collagen, and proteoglycans
Larger arteries have a well-defined external elastic lamina.
What is the outermost layer of blood vessels called?
Tunica Externa
Also known as Adventitia.
What is the primary composition of the Tunica Externa?
Type I collagen fibers
Contains some elastic fibers and fibroblasts.
What is the function of the Tunica Externa?
Provides structural support and anchors vessels
Supports neurovascular signaling to the vessel wall.
What are vasa vasorum?
A microvascular network
Nourishes the outer layers of large arteries and veins.
What is the clinical relevance of vasa vasorum?
Inflammation or proliferation is implicated in plaque rupture in atherosclerosis
Important for understanding vascular health.
What is the tunica media like in arteries?
Thick, muscular, elastic
The tunica media is responsible for the strength and elasticity of arteries, allowing them to handle high pressure.
What is the tunica media like in veins?
Thin
Veins have a thinner tunica media, which is suitable for lower pressure environments.
How does the tunica externa differ between arteries and veins?
Arteries have a relatively thinner tunica externa, while veins have a thicker tunica externa.
The tunica externa provides structural support and protection to both blood vessels.
What is the lumen size and shape in arteries?
Smaller, rounder
The smaller lumen helps maintain high pressure in arteries.
What is the lumen size and shape in veins?
Larger, irregular shape
The larger lumen allows veins to accommodate more blood at lower pressure.
Are valves present in arteries?
Absent
Valves are not needed in arteries because blood is pumped directly from the heart under high pressure.
Are valves present in veins?
Present in medium and large veins (especially lower limbs)
Valves in veins help prevent backflow of blood and assist in venous return to the heart.
What is the pressure like in arteries?
High
High pressure is necessary to distribute blood effectively throughout the body.
What is the pressure like in veins?
Low
Low pressure reflects the return of blood to the heart after it has circulated through the body.
What is the primary function of arteries?
Distribute blood under pressure
Arteries carry oxygenated blood away from the heart to various tissues.
What is the primary function of veins?
Return blood to the heart
Veins carry deoxygenated blood back to the heart for reoxygenation.
What clinical implications can arise from venous stasis and valve incompetence?
Contribute to varicose veins and chronic venous insufficiency
These conditions can lead to pain, swelling, and other complications in the lower limbs.
What is the formula for flow in the context of hemodynamics?
Q = ΔP / R
In the formula Q = ΔP / R, what does Q represent?
Flow (L/min)
In the formula Q = ΔP / R, what does ΔP represent?
Pressure gradient between two points
In the formula Q = ΔP / R, what does R represent?
Resistance (primarily in arterioles)
What happens to flow when resistance increases, such as in vasoconstriction?
Flow decreases unless pressure compensates
What condition can reduce flow despite high pressure?
Aortic stenosis
According to Poiseuille’s Law, how is resistance related to the radius?
R ∝ 1 / r^4
What effect does vasoconstriction have on resistance and flow?
Increases resistance and decreases flow
What effect does vasodilation have on resistance and flow?
Decreases resistance and increases flow
What other factors besides radius affect resistance?
Viscosity and length
Where is the highest pressure found in the circulatory system?
Aorta (~120 mmHg systolic)
Where is the steepest drop in pressure observed in the circulatory system?
Arterioles
Where is the lowest pressure found in the circulatory system?
Right atrium (~0–5 mmHg)
What do shock states involve regarding perfusion?
Decreased perfusion due to inadequate ΔP or increased resistance
Fill in the blank: Small changes in radius produce ______ changes in resistance.
exponential
True or False: Increased resistance always leads to increased flow.
False
What is the clinical approximation formula for Mean Arterial Pressure (MAP)?
MAP = DBP + 1/3(SBP - DBP)
What is the physiological formula for Mean Arterial Pressure (MAP)?
MAP = CO × TPR
What does CO stand for in the context of MAP?
Cardiac Output
How is Cardiac Output (CO) calculated?
CO = HR × SV
What does HR and SV stand for in the Cardiac Output formula?
- HR: Heart Rate
- SV: Stroke Volume
What does TPR represent in the MAP formula?
Total Peripheral Resistance
What is the minimum MAP value needed for adequate organ perfusion?
≥ 65 mmHg
What conditions can reduce MAP and lead to organ dysfunction?
- Sepsis
- Hypovolemia
- Heart failure
In ICU settings, what is used to maintain target MAP?
Vasopressors
Which vasopressor is commonly used to maintain target MAP?
Norepinephrine
What type of receptors are α1-adrenergic receptors?
Vascular smooth muscle
These receptors mediate vasoconstriction.
What is the effect of α1-adrenergic receptors on blood vessels?
Vasoconstriction
This effect is significant in regulating blood pressure.
What clinical application targets α1-adrenergic receptors?
α-blockers (e.g., prazosin)
These medications are used to treat hypertension.
Where are β2-adrenergic receptors located?
Skeletal muscle, coronary, hepatic vasculature
These locations are crucial for vasodilation effects.
What is the effect of β2-adrenergic receptors when activated by epinephrine?
Vasodilation
This occurs during stress responses, such as ‘fight or flight’.
What are the dose-dependent effects of epinephrine?
β2-mediated vasodilation at low doses; α1-mediated vasoconstriction at high doses
This highlights the importance of dosage in therapeutic contexts.
What is the role of Angiotensin II in the cardiovascular system?
Potent vasoconstrictor, stimulates aldosterone release
It is significant in the context of hypertension and fluid balance.
What effect does Angiotensin II have in chronic hypertension?
Stimulates vascular remodeling
This remodeling contributes to the pathophysiology of hypertension.
What is the function of Vasopressin (ADH) at the V1 receptor?
Vasoconstriction
This action aids in regulating blood pressure.
What does the V2 receptor of Vasopressin promote?
Water reabsorption in the kidney
This helps to maintain fluid balance in the body.
What is the purpose of the Baroreceptor Reflex?
Maintains short-term blood pressure stability
It is essential for rapid adjustments in blood pressure.
What is the Baroreceptor Reflex’s role during postural changes?
Rapid adjustment (orthostatic reflex)
This reflex helps prevent dizziness when standing up.
What is the myogenic mechanism of autoregulation?
↑ Pressure → stretch → reflex contraction → stabilizes flow.
Important in renal, cerebral, and coronary circulations.
What factors lead to metabolic regulation and vasodilation?
↓ O₂, ↑ CO₂, ↑ H⁺, ↑ K⁺, adenosine.
Matches blood flow to metabolic demand (e.g., during exercise).
What is Nitric Oxide (NO) synthesized from?
L-arginine.
Synthesized by eNOS.
What is the effect of Nitric Oxide on smooth muscle?
Activates guanylate cyclase → ↑ cGMP → smooth muscle relaxation.
What occurs in endothelial dysfunction regarding Nitric Oxide?
Inhibited, promoting vasoconstriction.
What is endothelin and its role?
Potent vasoconstrictor; upregulated in heart failure and pulmonary HTN.
What is the function of prostacyclin (PGI₂)?
Inhibits platelet aggregation and causes vasodilation.
True or False: Endothelial dysfunction is a hallmark of atherosclerosis, diabetes, and HTN.
True.
Fill in the blank: Endothelial dysfunction promotes _______.
vasoconstriction.
What are the high-pressure receptors involved in the baroreceptor reflex?
Carotid sinus (CN IX) and aortic arch (CN X)
These receptors are crucial for detecting changes in blood pressure.
What happens to baroreceptor firing when blood pressure increases?
Increased BP → ↑ baroreceptor firing → ↑ parasympathetic (vagal) tone, ↓ sympathetic tone → ↓ HR and vasodilation
This mechanism helps reduce blood pressure.
What is the response of the baroreceptor reflex to decreased blood pressure?
Decreased BP → ↓ firing → ↑ sympathetic tone → ↑ HR, contractility, vasoconstriction
This response aims to increase blood pressure.
What do the chemoreceptors in the carotid and aortic bodies respond to?
Sensitive to ↓ pO₂, ↑ pCO₂, ↓ pH
These changes trigger an increase in ventilation and sympathetic tone.
What is the effect of the chemoreceptor reflex on ventilation?
Increases ventilation and sympathetic tone
This response is vital for addressing changes in blood gas levels.
What are cardiopulmonary reflexes associated with?
Low-pressure baroreceptors in atria and pulmonary vessels
These reflexes help regulate volume status and ADH release.
Fill in the blank: Increased blood pressure leads to _______ tone and decreased heart rate.
parasympathetic (vagal)
This is part of the baroreceptor reflex mechanism.
True or False: The chemoreceptor reflex decreases sympathetic tone.
False
The chemoreceptor reflex actually increases sympathetic tone.
What is the Renin-Angiotensin-Aldosterone System (RAAS)?
A hormone system that regulates blood pressure and fluid balance.
What triggers the release of Renin?
↓ perfusion, ↓ Na⁺, or sympathetic activation.
What does Renin convert Angiotensinogen into?
Angiotensin I.
What enzyme converts Angiotensin I to Angiotensin II?
ACE (Angiotensin-Converting Enzyme).
List the effects of Angiotensin II.
- Vasoconstriction
- Aldosterone release → Na⁺ retention
- ADH release
- ↑ Thirst via hypothalamus
What is the role of Aldosterone?
Increases Na⁺ and water reabsorption, K⁺ excretion.
Where does Aldosterone act in the nephron?
On distal nephron (principal cells).
What is the overall contribution of Aldosterone?
Contributes to volume expansion.
What is ADH also known as?
Vasopressin.
Where is ADH released from?
Posterior pituitary.
How does ADH promote water reabsorption?
Inserts aquaporin-2 channels in the collecting duct.
What is Atrial Natriuretic Peptide (ANP)?
A hormone secreted by atria in response to stretch.
What are the effects of Atrial Natriuretic Peptide (ANP)?
- Promotes natriuresis
- Vasodilation
- Inhibits RAAS
What happens during chronic baroreceptor resetting?
Baroreceptors become less sensitive in sustained hypertension.
True or False: Chronic baroreceptor resetting leads to a failure to suppress high BP.
True.
What is the definition of Normal blood pressure according to the 2023 ACC/AHA Guidelines?
SBP <120 and DBP <80
What is the blood pressure range for Elevated blood pressure?
SBP 120–129 and DBP <80
What are the blood pressure values for Stage 1 Hypertension?
SBP 130–139 and DBP 80–89
What defines Stage 2 Hypertension?
SBP ≥140 and DBP ≥90
What percentage of hypertension cases are classified as Primary (Essential) Hypertension?
~90–95%
What are some multifactorial causes of Primary Hypertension?
- Genetic
- Dietary sodium
- Sympathetic overactivity
- Endothelial dysfunction
Name two causes of Secondary Hypertension.
- Renal artery stenosis
- CKD
List three other conditions that can cause Secondary Hypertension.
- Pheochromocytoma
- Cushing’s
- Hyperaldosteronism
- OSA
What are the non-modifiable risk factors for hypertension?
- Age
- Race (↑ in African Americans)
- Genetics
Identify three modifiable risk factors for hypertension.
- Obesity
- High salt intake
- Inactivity
- Alcohol
- Stress
True or False: Obesity is a non-modifiable risk factor for hypertension.
False
Fill in the blank: Primary Hypertension accounts for approximately _______ of cases.
[90–95%]
What is the minimum number of readings required to diagnose hypertension?
≥2 readings on ≥2 separate visits
What are the recommended methods for confirming a diagnosis of hypertension?
Ambulatory BP monitoring (ABPM) or Home BP Monitoring (HBPM)
What are the target organ damages associated with hypertension?
- Cardiac: LVH (ECG, echo), CHF
- Renal: Elevated creatinine, proteinuria
- CNS: Stroke, cognitive decline
- Ophthalmic: Hypertensive retinopathy
What laboratory tests are used to identify secondary causes of hypertension?
- TSH
- Aldosterone/renin ratio
- Catecholamines
What imaging is recommended for evaluating secondary causes of hypertension?
What is the first-line treatment approach for elevated or stage 1 hypertension without ASCVD risk?
Non-pharmacologic
When is pharmacologic treatment indicated for hypertension?
- Stage 2 HTN
- Stage 1 with ASCVD or 10-year risk ≥10%
What is the primary effect of thiazide diuretics?
↓ volume and TPR
Example: hydrochlorothiazide
What do ACE inhibitors inhibit?
Ang II synthesis
Example: lisinopril
What are some cautions associated with ACE inhibitors?
- Cough
- Angioedema
- Hyperkalemia
- Contraindicated in pregnancy
What do ARBs stand for?
Ang II receptor blockers
Example: losartan
What is the effect of dihydropyridines?
Vasodilation
Example: amlodipine
What is the effect of non-DHP calcium channel blockers?
↓ HR and contractility
Example: verapamil
What is the primary effect of beta-blockers?
Decrease CO
Used in CAD, HF; Example: metoprolol
What is the effect of alpha-blockers?
↓ TPR
Not first-line; Example: doxazosin
What are direct vasodilators known to cause?
Reflex tachycardia
Examples: hydralazine, minoxidil
What is the primary effect of central alpha-agonists?
↓ sympathetic outflow
Risk of rebound HTN; Example: clonidine
What is a complication of chronic hypertension related to the cardiovascular system?
LV hypertrophy → HFpEF
HFpEF stands for Heart Failure with Preserved Ejection Fraction.
What cardiovascular event can result from coronary artery disease due to chronic hypertension?
MI
MI stands for Myocardial Infarction.
What are two potential complications of chronic hypertension related to the aorta?
Aortic dissection, aneurysms
Aortic dissection and aneurysms can lead to life-threatening conditions.
What renal complication can arise from chronic hypertension?
Glomerulosclerosis → CKD → ESRD
CKD stands for Chronic Kidney Disease and ESRD stands for End-Stage Renal Disease.
What cerebrovascular complications are associated with chronic hypertension?
Stroke (ischemic and hemorrhagic), vascular dementia
Both types of strokes can have significant and lasting impacts on health.
What ocular complication can result from chronic hypertension?
Hypertensive retinopathy (AV nicking, cotton wool spots)
AV nicking refers to the alteration of the retinal blood vessels.
What dietary approach is recommended as a first-line lifestyle modification for hypertension?
DASH diet: ↑ fruits, vegetables, low-fat dairy; ↓ sodium, saturated fat
DASH stands for Dietary Approaches to Stop Hypertension.
What is the recommended sodium intake for individuals managing chronic hypertension?
<1.5–2.3g/day
Reducing sodium intake is crucial for blood pressure management.
How much can weight loss impact blood pressure?
1 mmHg per 1 kg lost; 5–20 mmHg for 10 kg
Weight loss can significantly reduce blood pressure levels.
What is the recommended amount of physical activity per week for hypertension management?
30 min/day, ≥5 days/week
Regular physical activity is essential for overall cardiovascular health.
What is the recommended limit for alcohol consumption for individuals with chronic hypertension?
Limit to 1–2 drinks/day
Moderation in alcohol consumption can help manage blood pressure.
What lifestyle modification can reduce cardiovascular risk independent of blood pressure?
Tobacco cessation
Quitting smoking greatly benefits cardiovascular health.
What methods may help with stress reduction and compliance in managing hypertension?
CBT, mindfulness
Cognitive Behavioral Therapy (CBT) and mindfulness practices can enhance overall well-being.
