CV Phy And Path 1 Flashcards by Jewel Brown

What is the effect of giant cell arteritis?

Inflammed vessel
Size of lumen is reduced
Can cause bitemporal vision loss

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Describe the contents and purpose of plasma.

55% of blood fluid in humans

92% water
8% glucose, hormone, proteins, mineral salts, fats, vitamins

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Describe RBC (erythrocytes). How does the shape aid in function?

Transport oxygen to and from lungs
Hemoglobin binds to oxygen

Shape increases surface area and allows them to fold to squeeze through small spaces

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Describe WBC (leukocytes)

Vital defenses against disease and infection

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What is the total volume of the blood?

4-5L

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Describe platelets.

Interact with clotting proteins to prevent or stop bleeding

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Describe the 3 methods by which CO2 is transported in the blood through capillaries.

CO2 carried in RBC
HCO3- (CO2 and H2O) dissolved in plasma as carbonic acid CO2 from tissues dissolved in plasma

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Describe the function of the lymphatic system in the cardiovascular system.

Lymphatic system collects excess fluid that drains from cells and tissue throughout the body and returns it to the bloodstream

Recirculated though the body

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Describe the overall arrangement of the cardiovascular system.

Heart is 2 pumps for 2 systems arranged in series

Systemic circulation and pulmonary circulation are arranged in series
Flow in all portions ranged in series must be the same

Subdivisions in each system arranged in parallel
Flow of portion in parallel must sum to equal flow in the system

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What must be true regarding the flow in portions that are parallel in the cardiovascular system?

Incoming must equal outgoing (equal flow)

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Define pressure.

Generated from myocardial contractions and stenosis of ventricles

Contract increases pressure

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What is vascular resistance determined by?

Vessel diameter
Blood viscosity (high cholesterol, polycythemia increased RBC, anemia)

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What effect does high cholesterol have on resistance? Polycythemia? Anemia?

Increases resistance , Decreases blood flow (clotting)

Increase resistance

Decrease resistance, decrease viscosity, decrease blood flow

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What is the equation for determining blood flow rate? What are the determinants for blood flow?

P1-P2 (pressure gradient)/ Resistance

Pressure and resistance

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Are pressure gradients necessary?

Yes needed for blood to flow

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What are the layers of lumen in the heart?

Innermost- tunica intima
Tunic media (muscular)
Outermost- tunica adventitia

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Describe the layers of histology in the heart. What are the coronary arteries?

Endocardium
Homologous with tunica intima
Dense fibroelastic CT, Continuous with valves

Myocardium
Homologous with tunica media

Epicardium
Homologous with adventitia

Pericardium

Coronary arteries
Homologous with vasa vasorum
(a network of small blood vessels that supply the walls of large blood vessels)

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What are pace maker cells?

Non-contractile cardiac muscle

Rhythmic electric signals create action potential so heart can function on its own

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Describe a cardiac myocyte.

Composed of bundles of myofibrils that contain myofilaments

Myofibrils have repeating microanatomical units

Mono or bi nucleated, frequent cell bifurcations

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Describe sacromeres.

Basic contractile units of myocyte
Composed of thick and thin filaments, myosin and actin

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Describe the cell junctions that exist between cardiac myocyte cells.

Intercalated discs: cell junctions
Mechanical coupling- desmosomes
Electrical coupling- gap junctions

Frequent cell bifurcations

These connections allow for the rapid travel of signals within the heart

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What are transverse tubules (T-tubule) in the cardiac myocyte?

Invaginations of the cell membrane
Permit rapid transmission of the action potential into the cell
Regulate cellular calcium concentration

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Describe the function of the sarcoplasmic reticulum (SR) and the SR Dyads.

SR: Stores calcium

SR dyads: functional junction formed by t-tubules and SR, within each dyad calcium entry through T-tubules elicits calcium release from SR

What organelles play an important role in the cardiac muscle?

Mitochondria

What is the basic sequence of the cardiac cycle? What does it result in?

Atrial systole and diastole Ventricular systole and diastole Results in pulsation blood flow in the arteries

What is a sphygmomanometry?

Measures arterial pressure changes (bp pump, gage, cuff) measure bp Systolic pressure/diastolic pressure

What is pulse pressure equal to for a Sphygmomanometry? Is it a reliable measurement?

Pulse pressure= systolic pressure - diastolic pressure Not reliable, someone in hyp crisis could have the same different as someone with normal BP

How is mean arterial pressure calculated for Sphygmomanometry? Is it reliable?

Mean arterial pressure = 1/3(pulse pressure) + diastolic pressure Reliable, shows average BP overtime

Where is pulsatile flow the greatest?

In the aorta

What occurs during systole?

Inflow is greater than outflow Increase in arterial volume Increase in arterial pressure

What occurs during diastole?

Outflow is greater than inflow Arterial volume decreases Arterial pressure decreases

Describe the autorhymicity of the heart?

Controlled by pace marker cells (under autonomic control) Cardiac muscle acts as 2 separate single unit muscles: atrial and ventricular Electrical and mechanical coupling in intercalated discs

What is the basal electrical rhythm (BER)?

Present in all cardiac muscle fibers Cyclical BER activity of the pacemaker cells in SA node regulates rate of myocardial muscle contractions

Describe the order of the cardiac conduction system.

Sinoatrial node Atrioventricular node Atrioventricular bundle (Bundle of HIS) Bundle branches Purkinje fibers

What is the function of the internodal pathway?

Connects SA node to AV node Signals between pacemaker cells

What is the function of bauchmann’s bundle?

Conducts impulses from R to L atrium Simultaneous contraction

What is the function of the SA node? Where is it located?

Pacemaker (ANS can act on this) Generate impulses Border of superior VC and RA

What is the function of the AV node? Where is it located? Describe AV delay.

After SA node at the base of RA Delays signals we don’t want A and V to contract at same time (A must contract first) Also contains pacemaker cells

Describe the bundle of His.

Connects the atria to the ventricles

Describe the bundle branches.

Conduct the impulses through the interventricular septum

Describe the purkinje fibers.

Depolarize the contractile cells of both ventricles to cause ventricular contraction

What is the difference between effect of depolarization vs hyperpolarization?

Depolarize = contract Hyperpolarize = relax

Describe the function of diastolic depolarization.

Occurs spontaneously Slow influx of Na from leaky channels to return pacemaker cell to threshold Determines heart rate

Deceive the order of pacemaker potentials.

Begins at -40mV (threshold) Phase 4: slow influx of Na+ (prepotential) to reach threshold) Phase 0: Rapid influx of Ca2+ (depolarization, cell becomes positive) Phase 3: outflux of K+ (repolarization, cell becomes more negative/less positive) Leaky channels allow for diastolic depolarization back to threshold

Which phase describes the change in depolarization that is associated with sympathetic and parasympathetic stimulation?

Phase 4

Describe the effects of sympathetic stimulation on the action potential of pacemaker cells.

Sympathetic stimulation and epinephrine depolarize the pacemaker cell and speed up the depolarization rate (spontaneous diastolic depolarization) Increases heart rate

Describe the effects of parasympathetic stimulation on the action potential of pacemaker cells.

Parasympathetic stimulation hyperpolarize the pacemaker cell and slows depolarization Decreases heart rate Starts at a more negative membrane potential

What is the average BPM of the heart produced by BER?

100 Bpm

What controls firing of the SA?

ANS

What is the effects to heart rate with cardiac accelerator nerve (sympathetic) and vagus nerve (parasympathetic)?

Sym: tachycardia > 100BPM Para: Bradycardia: <60BPM

What is the difference between stimuli for cardiac muscle vs pacemaker cells?

Muscles receive external stimuli while pacemakers receive internal signals

What is the order of phases for muscle cells vs pacemaker cells?

Muscle: 4, 0, 1, 2, 3, 4, repeat Pacemakers: 4, 0, 3, 4 repeat

Describe the process of the ventricular cardiac muscle action potentials.

Phase 0 - fast depolarization (+) Influx gNa+, outflux gK+ Phase 1 - slight repolarization – decreased influx gNa+ Phase 2 - plateau – Balanced increased influx gCa2+ (contraction) and increased outflux gK+ Phase 3 - repolarization – decreased influx gCa2+ and increased outflux gK+ Phase 4 - Resting – Approx. 300 mSec

Describe the refractory period of the muscle cell action potential.

Absolute: no summation of excitatory cell (myocyte will not contract) Relative: supranormal excitability (premature ventricular contraction before it is totally filled)

What is the longest phase of muscle cell action potentials?

Phase 2