Term
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Definition
1. heart (pump)
2. blood vessels (tubes)
3. blood (transporter)
Function: long distance transport |
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Term
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Definition
1. Pulmonary: replenishes O2 in blood cells
2. Systemic: pumps blood throughout the body |
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Term
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Definition
1. Less on side that pumps through pulmonary
2. More on side that pumps throughout the body |
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Term
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Definition
1. Highest BP at arteries
2. Pressure builds as tubes become narrower
a. Large arteries → small arteries → arterioles
3. Lowest at capillaries
4. Begin to rise going back to heart, but lower than at the beginning of the circuit
a. Venules → veins |
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Term
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Definition
1. Located between lungs on top of diaphragm
2. Cells: branched, striated and multinucleated
3. 4 basic chambers:
a. Right and left atria
b. Right and left ventricles |
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Term
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Definition
a. Right AV/tricuspid valve
b. Left AV/bicuspid/mitral valve
c. Pulmonary semi-lunar valve
d. Aortic semi-lunar valve
1. 99% of cells: contractile cells
2. Bundle of His, Purkinje fibers: used for conduction |
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Term
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Definition
a. Attach to papillary muscles
b. Prevents valves from blowing out/back into atria |
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Term
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Definition
a. Pulmonary artery
b. Systemic artery/aorta |
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Term
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Definition
1. Passive filling during ventricular and atrial diastole (relaxed state of heart)
a. Low pressure, valve is open
b. Flows into atria and down concentration gradient into ventricle
c. 80% of filling is passive
2. Atrial contraction
a. Accounts for last 20% of filling
3. Isovolumetric contraction
a. No change in volume in lower parts of heart (ventricles)
b. Pressure builds up
4. Blood pushed into arteries due to pressure
a. Ventricle ejection
5. Isovolumetric ventricular contraction
a. Pressure still present
b. Valves are closed |
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Term
| Pressure Generated by the Heart |
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Definition
1. Hydrostatic Pressure (P): force exerted on the container by fluid
a. Moves from high to low pressure
b. Opposed by resistance (R):
i. Length of tube, radius of tube, viscosity of fluid
ii. Main influence: radius
c. Arterioules absorb pulsations of pumps
1. EDV: end diastolic volume: max amount of blood at then end of relaxation
2. ESV: end systolic volume: max amount of blood at end of contraction
3. Stroke Volume = EDV – ESV = 1 stroke |
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Term
| Autorhythmic (Pacemaker Cells) |
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Definition
1. Na+/ K+ leak channels open
a. Net movement of Na+
b. Slow depolarization
2. Threshold at -40 mV, Ca2+ (voltage gated) channels open at threshold
a. Fast depolarization
b. Ca+ moves into cell, cell reaches ~ +10 mV then Ca+ channels close
3. K+ channels open, K+ moves out of cell, fast repolarization, K+ channels close at ~-60mV
4. No resting membrane potential, always changing
a. Pacemaker potential |
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Term
| Ways to Change Rate of APs (of Pacemaker Cells) |
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Definition
1. ↑ K+ permeability: causes hyperpolarization which ↑ time it takes to reach threshold; slows rate
2. ↑ Na+ permeability: reaches threshold faster, ↓ time to reach threshold; rate becomes faster
3. ↑ Ca2+ permeability: takes less time to repolarize/go through AP; HR becomes faster
4. ↓ Ca2+permeability: takes longer to go through cycle: HR slows |
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Term
| Excitation-Contraction Coupling |
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Definition
1. AP depolarizes plasma membrane
2. Ca++ channels open along plasma membrane, Ca++ moves into cell
3. ↑ Ca++ in cell causes SR to release even more Ca++
4. Ca++ binds to troponin
5. Tropomyosin moves out of the way
6. Myosin and actin bind |
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Term
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Definition
1. Sympathetic innervation: stimulates an ↑ in HR
a. Done by keeping Na+/K+ channels open longer and stimulates more Ca2+ channels to open
b. ↑ rate of depolarization
2. Parasympathetic innervation: stimulates a ↓ in HR
a. ↑ K+ permeability (hyperpolarizes cell)
b. ↓ Ca2+ permeability—takes longer to move through AP event |
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Term
| Measuring the Electrical Activity of the Heart |
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Definition
P wave: depolarization of atria
QRS complex: depolarization of ventricles
T wave: repolarization of ventricles
P-R segment: time delay between atrial depolarization vs. ventricular depolarization |
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Term
| Complications of cardio vascular |
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Definition
1. 1st degree heart block: P-R segment unusually long; long delay between atrial and ventricular depolarization
2. 2nd degree heart block: delay is so long that the atria repolarize before ventricles do
3. 3rd degree heart block: fatal; no communication between atria and ventricles
4. Atrial fibrillation: unsynchronized; some areas of muscles relaxed, other contracted
5. Ventricular fibrillation: covers up atrial waves
6. Bradycardia: slower than normal HR
a. Normal HR: 60-100 bpm
7. Tachycardia: faster than normal HR
8. Arrhymia: irregular heart beats (pace or rate) |
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Term
| Heart generates and maintains the pressure in the CV system |
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Definition
1. Tracked by Wiggers’ Diagram
a. “a”: contraction of atria, pressure ↑
b. When aortic pressure is the same as left ventricle (LV) pressure, AV valve opens
c. “c”: bump caused by contractions of ventricles and places pressure on LV
d. “v”: valve opens when ventricular pressure drops below atrial pressure, valve opens
e. T-wave: refractory period |
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Term
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Definition
| volume before contraction; when it’s relaxed |
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Term
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Definition
a. 1st sound: closing of AV valve
b. 2nd sound: closing of semilunar valve |
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Term
| Amount of Blood Pumped By The Heart |
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Definition
1. CO = HR · SV
a. CO: cardiac output = vol/min
b. HR: heart rate = bpm
c. SV: stroke volume = volume per beat |
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Term
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Definition
a. Frank-Starling (Law of the Heart)
i. Length-Tension Relationship
ii. Force: indicated by SV
iii. Stretch: indicated by EDV
iv. the more it stretches, the more it recoils.
b. Resistance Downstream |
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Term
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Definition
i. Minimal parasympathetic innervation of ventricles
ii. Decreases parasympathetic output, which dominates at rest
iii. Contractility: strength of contraction (per given volume) |
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Term
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Definition
1. Defined: push of molecules against each other and against the walls of the container they’re in
2. Hydrostatic: pressure against walls (no movement)
3. Dynamic: pressure against walls while sliding downstream (with movement) |
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Term
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Definition
1. Fluids and gasses move from high to low
2. Movement expressed in two ways
a. Velocity: distance per unit time
b. Flow: volume per unit time
i. Flow = change in pressure/resistance |
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Term
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Definition
1. Viscosity: thickness of fluid
a. Lessened by smooth endothelial lining of wall
b. Minimal change
2. Length of tube
a. ↑ length = ↑ resistance
b. Length does not change much
3. Radius of tube
a. Radius change: R α 1/r4
i. Ex. R = 4 → R = 2; R = 1/44 → R = 1/24 |
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Term
| Pulses: Arteries “Absorb” Pulses of Blood |
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Definition
1. Ventricular Contraction
a. Ventricles contracts
b. Semilunar valve opens
c. Aorta and arteries expand and store pressure in elastic walls |
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Term
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Definition
a. Isovolumic ventricular relaxation
b. Semilunar valve shuts
c. Elastic recoil of arteries sends blood forward into rest of circulatory system |
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Term
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Definition
1. Arterial Pressure: systolic/diastolic = 120/80 (normal)
a. Inflate up to 150 or 160 mmHg
b. ↑ pressure, artery closes, silence
c. Low murmur in pulses, 1st is systolic (systolic BP)
d. Silence resumes (diastolic BP)
2. Pulse Pressure: difference between high number and low number
a. Ex. Systolic = 120, diastolic = 80 → 120 -80 = 40
b. Diastolic: ⅔ time of cardiac cycle
c. Systole: ½ time of cardiac cycle
3. Mean Arterial Pressure = MAP
a. MAP = low/diastolic + 1/3(pulse pressure) |
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Term
| Blood Vessels/Control of Blood Flow |
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Definition
A. Types
1. Arteries
a. Diameter: 4 mm, Wall Thickness: 1.0 mm
b. Consists of endothelium, elastic tissue, smooth muscle, fibrous tissue
2. Arterioles
a. Diameter: 30.0 μm, Wall Thickness: 6.0 μm
b. Consists of endothelium and smooth muscle
3. Capillaries
a. Diameter: 8.0 μm, Wall Thickness: 0.5 μm
b. Consists of endothelium
4. Venules
a. Diameter: 20.0 μm, Wall Thickness: 1.0 μm
b. Consists of endothelium and fibrous tissue
5. Veins
a. Diameter: 5.0 mm, Wall Thickness: 0.5 mm
b. Consists of endothelium, elastic tissue, smooth muscle, fibrous tissue |
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Term
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Definition
1. Smaller arteries and the arterioles act as valves to control flow route
a. Arterioles control downstream flow
b. Vasoconstrict: ↓ radius of blood vessel
c. Vasodilate: ↑ radius of blood vessel
i. Both occur to redirect blood flow
d. Small arterioles have sphincters
2. Capillaries missing 2-3 vessel layers
3. Venous Return
a. Skeletal Muscle Pumps
i. Help blood return to the heart
ii. Valves prevent backflow
iii. When the skeletal muscle compress the veins, they force blood toward the heart
b. Respiratory Cycle Pressure Changes
i. Helps return blood to the heart
ii. Contraction of diaphragm causes pressure ↑ which causes ↓ in area of thoracic cavity
iii. Blood flows from viscera to thoracic cavity |
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Term
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Definition
A. 20% of fluid pushed out at capillaries is not absorbed back into blood vessels
B. Drains blood filtrate left behind in the tissues (ECF)
C. Houses cells of the immune system
D. Transports fats from GI to blood
E. Complimentary to entire body
F. Not a closed loop—contents dumped back into blood stream in the vena cava |
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Term
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Definition
A. Filtration: fluids leaving
B. Absorption: fluids entering |
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Term
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Definition
| fluids reentering after they left |
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Term
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Definition
A. 2 driving forces
1. Hydrostatic Pressure: inside high, outside low
2. Osmotic Pressure: oncotic pressure—solutes inside vs. solutes outside
a. Difference of concentration of solutes vs. where the water is. |
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Term
| Distribution of flow depends on relative resistance of different arterioles |
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Definition
| 1. Flow: flow in one tissue is relative to the flow in other tissues |
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Term
| Intrinsic Control of Blood Flow |
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Definition
1. Response to injury
2. If change in blood flow → autoregulation (flow α ΔP/R)
3. If change in metabolic needs → active hyperemia
a. ↑ tissue metabolism → ↑ release of metabolic vasodilators into ECF → dilation of arterioles → ↓ resistance = ↑ blood flow → O2 and nutrient supply to tissue ↑ as long as metabolism is ↑
4. If blood flow temporarily stops → reactive hyperemia
a. ↓ blood flow due to occlusion → metabolic vasodilators accumulate in ECF → vasodilation of arterioles but occlusion prevents blood flow → remove occlusion → ↓ resistance = ↓ blood flow as vasodilators wash away, arterioles constrict and blood flow returns to normal
5. Vasodilation: ↓ O2, ↑ CO2, ↑ H+ |
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Term
| Extrinsic Control of Flow |
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Definition
1. Sympathetic innervation (tonic release)
2. Other autonomic neurons
3. Hormones
4. Extrinsic factors can act on smooth muscle (direct) or endothelial cells (indirect) |
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Term
| Influence on Blood Velocity |
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Definition
1. Velocity of blood on velocity
a. High in arteries and arterioles
b. Low in capillaries
c. Moderate-High in veins |
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Term
| Influences on Blood Pressure |
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Definition
1. In CV system, homeostasis revolves around maintaining pressure
2. MAP = CO ∙ TPR
a. MAP: mean arterial pressure
b. CO: rate in
c. TPR: total peripheral resistance, rate out |
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Term
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Definition
1. Baroreceptors (mechanoreceptors)
a. Carotid arteries in neck and aortic arch
i. Tonic-type receptors
ii. Sensitive to stretch—the more the stretch, the more APs are fired |
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