Exam 3 (Heart) Flashcards
What are the MAP values for hypertension and hypotension?
hypertension: MAP > 105
hypotension: MAP < 70
What is the valve between the left ventricle and the aorta?
aortic semilunar valve
What is stenosis?
heart valve doesn’t open properly; could be narrowed
happens before/during LUB
Describe the process of electrical conduction in the heart.
- electrical signal begins at SA node
- signal is conducted through internodal pathway (fast)
- conduction stops at fibrous wall between atria and ventricles
- depolarization through AV bundle and Purkinje fibers (fast)
- depolarization spreads upward from apex to fibrous wall
What is the equation for pulse pressure?
PP = systolic P - diastolic P
What effect does norepinephrine have on MAP?
arteriolar smooth muscle → vasoconstriction → increased peripheral resistance → increased MAP
ventricular contractile muscle → increased stroke volume → increased CO → increased MAP
SA node → increased HR → increased CP → increased MAP
What are the four components of blood vessels?
- endothelium (secretion + absorption)
- elastic tissue (energy storage)
- smooth muscle (change vessel diameter)
- fibrous tissue (stiffness; stretch resistance)
What is the equation for mean arterial pressure (MAP)?
MAP = DP + 1/3(SP - DP)
What is the condition of the heart during the PQ segment?
completion of ventricular filling
atria contract → last 20% of ventricular filling + some backflow to veins (jugular pulse)
What are the properties of capillaries?
endothelium
site of exchange
What are the valves between the atria and the ventricles?
AV valves
What are the properties of venules?
endothelium + fibrous tissue
collecting vessels
What effect does ACh have on MAP?
ACh → SA node → increased heart rate → increased cardiac output → increased MAP
What are the factors that affect MAP?
- peripheral resistance
- cardiac output (CO = HR x stroke volume)
- blood volume (regulated by kidneys)
- distribution of blood in circuitry
What is the P wave in an ECG?
arterial depolarization
What is the ST segment in an ECG?
ventricular contraction
What is the PQ/PR segment in an ECG?
atrial contraction
What happens during the ST segment?
ventricular ejection → semilunar valves open
What are the types of cardiac muscle?
contractile: like skeletal; longer contraction duration excitatory: autorhythmic cells conductive: conduct electrical signals faster than contractile muscle
What is the equation for flow rate (Q)?
Q = ΔP/R
Which capillary/interstitial pressures affect absorption?
Πp
What is the driving pressure?
fluid pressure created by the ventricles
Which capillary/interstitial pressures affect filtration?
Pc, Pif, Πif
What happens during the T wave?
isovolumic ventricular relaxation
ventricular repolarization; retrograde flow → semilunar valves close (DUP)
Name the parts of an ECG.
What are the causes of edema?
capF >> capA
- increase in Pc
- increase in Πif
- increase in Πp (caused by albumin breakdown)
- inadequate drainage of lymph
What is the condition of the heart before the P wave?
heart at rest
atrial and ventricular diastole; atria fill from veins; ventricles fill from gravity
What are the two types of pressure in capillaries and interstitial fluid?
- hydrostatic: based on fluid pressure
- osmotic: based on solutes
What are the properties of arterioles?
endothelium + smooth muscle
vasoconstrict or vasodilate
site of variable resistance
What is cardiac regurgitation?
leaking valve; blood can flow backwards or through closed valve
happens after LUB
Where is the cardiovascular center and what does it do?
medulla oblongata; coordinates BP through autonomic nervous system
What is the T wave in an ECG?
ventricular repolarization
What is the QRS complex in an ECG?
progressive ventricular depolarization
What is the equation for resistance (R)?
R = 1/r4
What is fibrillation?
arrhythmia of rapid, irregular, and unsynchronized contraction
What is elastance, and which blood vessel type has more?
ΔP/ΔV (ability to return to unstretched state)
arteries have more elastance
What is compliance, and which blood vessel type has more?
ΔV/ΔP (ability to stretch)
veins are more compliant
What are the right and left heart circuits?
right: pulmonary circuit left: systemic circuit
What is artherosclerosis?
plaques in arteries harden them → lower elastance + movement energy → higher BP + lower blood flow
What is the equation for flow velocity?
v = Q/A
A = cross-sectional area
Where are baroreceptors and what do they do?
carotid arteries + aorta; stretch sensitive mechanoreceptors
What are systole and diastole?
systole: cardiac muscle contracting
diastole: cardiac muscle relaxing
What happens during the QRS complex?
isovolumic ventricular contraction
Q (depolarization of AV bundle) → S (ventricular depolarization) → AV valves forced closed (LUB)
What are the properties of veins?
endothelium + elastic tissue + smooth muscle + fibrous tissue
hold 60% of blood; can change diameter
What is the pericardium?
fluid filled sack around heart; lubricates and prevents rubbing
What is the valve between the right ventricle and the pulmonary artery?
pulmonary semilunar valve
What are the properties of arteries?
endothelium + elastic tissue + smooth muscle + fibrous tissue
energy required to stretch → stored energy
What are the types of pacemaker cells?
sinoatrial node: 70 bpm atrioventricular node: 50 bpm ventricular cells: 35 bpm
