Cardiovascular Conditions Section 2 Flashcards
(92 cards)
Which wave on an EKG represents depolarization of the atria and the firing of the SA node?
P wave
On an EKG, what represents depolarization of the ventricles? (AV node to ventricles)
The QRS complex
On an EKG, what may represent repolarization of the Perkinje fibers or a hypokalemia?
U wave
On an EKG, what represents repolarization of the ventricles?
T wave
What is cardiac output?
The amount of blood pumped by each ventricle in 1 minute
How do you calculate CO?
Stroke volume x HR per minute
What is the range of cardiac output for a normal adult at rest?
4-8L/min
What are the main factors influencing BP?
Cardiac Output x SVR (systemic vascular resistance) = BP
What is SVR?
Systemic Vascular Resistance; force opposing movement of blood in within vessels
What is the principal factor that determines SVR?
Radius of small arteries and arterioles
What happens when a-adrenergic receptors are stimulated by noepinephrine?
Vasoconstriction
What kind of receptors do blood vessels have?
a-adrenergic and b2-adrenergic
Where are b1-adrenergic receptors found?
In the heart
What neurotransmitter stimulates the b2-adrengergic receptors? What happens?
Epinephrine; vasodilation
Name where each adrenergic receptor is found and what happens when activated
a1:
- vascular smooth muscle; vasoconstriction
- heart; more contractility
a2:
- vascular smooth muscle; vasoconstriction
-presynaptic nerve terminals; inhibition of norepinephrine release
b1:
- Heart; Increased contractility and heart rate and conduction
- Kidney; Renin secretion
b2:
- Smooth muscle in blood vessels in heart; vasodilation
How does sodium contribute to blood pressure?
- Sodium attracts water
- Increases ECF volume
- This increases venous return to the heart and stroke volume
- Cardiac Output and Blood Pressure increase
What hormones secreted by the renal medulla have vasodilator effects?
Prostaglandins
What does Aldosterone do?
Stimulates kidneys to retain sodium and water
What is primary hypertension?
Elevated blood pressure without a known cause
What is secondary hypertension?
Elevated blood pressure with a cause that can be identified and corrected
What are 8 common causes of secondary hypertension?
1) Cirrhosis
2) Genetic defect of narrow artery
3) Drugs
4) Endocrine problems
5) Neurological problems
6) Pregnancy
7) Renal disease
8) Sleep apnea
What is the hemodynamic hallmark of hypertension?
Persistently increased systemic vascular resistance
Describe the different risk factors for hypertension?
Age
Alcohol: 2 drinks per day for males and 1 for females
Diabetes
Ethnicity: Higher in blacks
Sodium Intake
Family history
Gender: More common in men in young adulthood and middle age. More common in women after 64 years
Serum lipids: More common in pts with high cholesterol, triglycerides, and hyperlipidemia
Obesity
Sedentary Lifestyle
Socioeconomic Status: More common in poor and low educated populations
Stress
Tobacco
What does angiotensin do to the body?
Narrows blood vessels