Download 6 Heart Physiology Homework

Cardiovascular System: Intrinsic Conduction System
1.
The intrinsic conduction system consists of _______________ ____________ cells that initiate and
distribute _______________ throughout the heart.
2.
The intrinsic conduction system coordinates heart activity by determining the direction and speed of
________________. This leads to a coordinated heart contraction.
3.
List the functions for the following parts of the intrinsic conduction system:
a. SA node ____________________________
b. Internodal pathway __________________________
c. SKIP
d. AV bundle (bundle of His) ____________________________
e. Bundle branches __________________________
f.
4.
Purkinje fibers ____________________________
The action potentials spread from the autorhythmic cells of the intrinsic conduction system (electrical
event) to the ______________ cells. The resulting mechanical events cause a heartbeat.
5.
A tracing of the electrical activity of the heart is called a/an ________________.
6.
What do the following wave forms reflect?
a. P wave ____________________________
b. QRS complex ____________________________
c. T wave ____________________________
7.
In a normal ECG wave tracing, atrial repolarization is hidden by the ___________________.
8.
Electrical events lead to mechanical events. For example, the P wave represents ____________
depolarization, which leads to atrial _____________.
9.
10.
A left bundle branch block would have a wider than normal wave for the ____________.
An abnormally fast heart rate (over 100 beats per minute) is called ______________.
1
Answers
1.
autorhythmic cardiac, impulses (action potentials)
2.
heart depolarization
3.
a.
initiates the depolarizing impulse and sets the pace for the entire heart
b.
link between the SA node and the AV node
c.
SKIP
d.
delay occurs allowing atria to contract
e.
convey impulses down the interventricular septum
f.
convey the depolarizations throughout the ventricular walls
4.
contractile
5.
ECG—electrocardiogram (or EKG)
6.
a.
atrial depolarization
b.
ventricular depolarization
c.
ventricular repolarization
7.
QRS complex
8.
atrial, contraction
9.
QRS complex
10.
tachycardia
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Cardiovascular System: Cardiac Action Potential
1.
How do the waves of depolarization, generated by the autorhythmic cells spread to the muscle cells?
_____________________
2.
Name the two major channels essential for generating an action potential and indicate which way the ions
move (circle the correct one):
1. ______________ channels
into
or
out of
2. ______________ channels
into
or
out of
3.
If the sodium channel is open, the inside of the cell would be relatively more ______________.
4.
The pacemaker potential is due to a/an (decreased or increased) efflux of ____ ions compared to a normal
influx of ____ ions.
5.
Threshold for the action potential in the SA node is at ____ mV. What channels open, causing
depolarization? ______________
6.
The reversal of membrane potential causes the _____ channels to open, causing the ______________ of
the membrane.
7.
The ______________ pumps sodium out and potassium into the cell, restoring ion concentrations to their
resting levels.
8.
Where is calcium stored in the contractile cells? ______________
9.
Gap junctions allow what cations to pass into the cardiac contractile cells, causing the opening of voltagegated sodium channels? _________________________
10.
What channels in the autorhythmic cells allow ions to leak in, producing a pacemaker potential?
______________
11.
What channels in the autorhythmic cells bring about depolarization? _____________
3
Answers
1.Through gap junctions
2. 1. sodium, into
2. potassium, out of
3. positive
4. decreased, potassium, sodium
5. –40, calcium channels
6. potassium, repolarization
7. Na+-K+ ATPase
8. Sarcoplasmic reticulum
9. Sodium, calcium, and potassium
10. Sodium channels
11. Calcium channels
4
Cardiovascular System: Cardiac Cycle
1.
Valves open in response to __________________________ on their two sides.
2.
List the chambers/vessels that the four valves connect:
Chamber
Valve
Chamber/Vessel
Pulmonary semilunar
Aortic semilunar
Mitral
Tricuspid
3.
a. Ventricular filling occurs during ______________ ventricular ____________.
b. Blood flows through the __________, or __________, valves into the ventricles.
4.
During ventricular systole, what closes the AV valves?
5.
During ventricular systole, what opens the semilunar valves?
6.
Why is hypertension hard on the heart?
7.
Average stroke volume is approximately how many ml? ________
8.
During the two phases listed below, state whether the AV and semilunar valves are open or closed:
Phase
Ventricular filling
Ventricular ejection
AV Valves
Semilunar Valves
5
Answers
1. differences in blood pressure
2.
Chamber
Valve
Chamber/Vessel
Right ventricle Pulmonary semilunar Pulmonary trunk
Left ventricle
Aortic semilunar
Semilunar aorta
Left atrium
Mitral
Left ventricle
Right atrium
Tricuspid
Right ventricle
3. a. mid to late, diastole
b. atrioventricular, AV
4. Intraventricular pressure being greater than atrial pressure.
5. Intraventricular pressure being greater than pressure in the pulmonary trunk and aorta.
6. With hypertension, the ventricular pressure must rise higher to open the semilunar valves. For the same
increase in pressure in a normotensive person, less blood is ejected in a hypertensive person. Thus, the
heart of someone with hypertension must work harder to eject the same stroke volume.
7. 70
8.
Phase
AV Valves
Semilunar Valves
Ventricular filling
Open
Closed
Ventricular ejection Closed
Open
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Cardiovascular System: Cardiac Output
1.
Define cardiac output (CO).
2.
Write the equation for CO.
3.
Define stroke volume (SV).
4.
Write the equation for SV.
5.
Write the normal values (include correct units) for the following:
a. HR (heart rate) = ___________________________
b. SV (stroke volume) = ___________________________
c. EDV (end diastolic volume) = ___________________________
d. ESV (end systolic volume) = ___________________________
6.
Given the above normal values for HR and SV, calculate cardiac output:
CO =
7.
Explain how the following factors affect HR, SV, and CO by placing arrows (, , or  for no change)
under them.
HR
SV
CO
a.  Venous return
____
____
____
b. Exercise
____
____
____
c.  Calcium
____
____
____
d.  HR
____
____
____
8.
Why would stroke volume increase with an increase in the sympathetic nervous system or an increase in calcium?
9.
Why would stroke volume increase when heart rate slows down?
10.
If stroke volume is 75 ml/beat and heart rate is 80 beats/min, how many 2-liter soda bottles would equal the
correct volume? ______________
7
Answers
1.
The amount of blood pumped out by each ventricle in one minute
2.
CO = HR  SV
3.
The amount of blood ejected from each ventricle in one heartbeat
4.
SV = EDV – ESV
5.
a. 75 beats/minute (bpm)
b. 70 ml/beat
c. 120 ml
d. 50 ml
6.
CO = HR  SV
= 75 beats/minute x 70 ml/beat
= 5250 ml/minute or 5.25 L/minute
7.
HR
SV
CO
a.
 Venous return



b.
Exercise



c.
 Calcium



d.
 HR



8.
An increase in contractility leads to an increase in the force of contraction.
9.
An increase in filling time leads to an increase in end diastolic volume.
10.
3 bottles
8
Cardiovascular System: Anatomy Review: Blood Vessel Structure and Function
1.
Name the three layers or tunics of the blood vessel wall and what they are composed of.
Location
Tunic Name
Composed of
Innermost
Middle
Outer
2.
3.
In the following list of characteristics, put “A” for artery, “C” for capillary, and “V” for vein:
____ contain the lowest pressure
____ contain the highest pressure
____ has thick tunica media
____ thin tunica media
____ smallest of the blood vessels
____ carries blood away from heart
____ largest lumen—blood reservoir
____ has only one tunic (intima)
____ carries blood toward the heart
____ site of exchange of nutrients
Name the three groups of arteries:
1. _________________________
2. _________________________
3. _________________________
4.
______________ arteries have a thick tunica media with the greatest amount of elastin. They also
experience the greatest pressure and the widest variation in pressure. The best example is the
______________.
5.
Compared to the arteries above, the muscular arteries have more smooth muscle but less ______________.
They deliver blood to specific organs. The ______________ artery delivers blood to the kidney and would
be an example of this type of artery.
Small changes in the diameter of these blood vessels greatly influence blood flow and blood
______________. Stimulation of vasomotor fibers would cause (vasoconstriction or vasodilation) of the
blood vessels.
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6.
The smallest arteries are called ______________. The steepest drop in blood pressure occurs in these
vessels, thus they offer the greatest ______________ to flow.
An increase in blood flow through a feeder arteriole will (increase or decrease) blood flow through the
capillary.
7.
Capillaries:
The ______________ is a short vessel that directly connects the arteriole and venule. When blood flows
through this vessel, there is no exchange of materials.
The _________________________ controls blood flow into the true capillaries. Exchange of materials
takes place from these capillaries.
Compared with blood pressure in the arteries, blood pressure is _______ (high or low) in the capillaries.
8.
Venules:
The smallest venules are formed when capillaries unite. They consist mainly of ______________ around
which a few fibroblasts congregate. Blood flow continues to (increase or decrease) in the venules.
9.
Veins:
Veins have three distinct tunics, with the tunica ______________ being the heaviest. Veins have
______________ walls and ______________ lumens than arteries.
10.
Because pressure is lower in the veins, special adaptations are necessary to return blood to the heart. These
three structural adaptations are:
1. ______________. Here, ______________ prevent backflow as blood travels toward the heart.
2. ______________. Here, contracting ______________ muscles press against veins, forcing blood
through #1 above.
3. ______________. During inspiration, pressure (increases or decreases) in the thoracic cavity and
(increases or decreases) in the abdominal cavity. This results in an upward “sucking” effect that pulls
blood toward the heart.
10
Answers
1.
2.
Location
Tunic Name
Composed of
Innermost
Tunica intima
Endothelium
Middle
Tunica media
Smooth muscle + elastin
Outer
Tunica adventitia
Collagen fibers
V
A
A
V
C
A
V
C
V
C
contain the lowest pressure
contain the highest pressure
has thick tunica media
thin tunica media
smallest of the blood vessels
carries blood away from heart
largest lumen—blood reservoir
has only one tunic (intima)
carries blood toward the heart
site of exchange of nutrients
3. 1. elastic arteries
2. muscular arteries
3. arterioles
4.
5.
6.
7.
8.
9.
10.
Elastic, aorta
elastin, renal, pressure, vasoconstriction
arterioles, resistance, increase
shunt, precapillary sphincter, low
endothelium, decrease
adventitia, thinner, larger
1. Venous valves, one-way valves
2. Skeletal muscle pump, skeletal
3. Respiratory pump, decreases; increases
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Cardiovascular System: Measuring Blood Pressure
1.
Blood flow is generated by the _________________________________. Blood pressure results when that
flow encounters ______________ from the vessel walls.
2.
Blood pressure is expressed in ______________ of mercury and is written as ______________.
3.
Blood flows in layers within the lumen of blood vessels, with the layers in the middle of the lumen flowing
fastest. This is known as ______________ flow.
4.
The maximum pressure exerted by blood against the artery wall is known as ______________ pressure
(SP) and is the result of ventricular ______________. Normal SP is about ______ mmHg.
5.
What does the dicrotic notch represent?
Answer: ____________________________________________________________________________
6. ______________ pressure (DP) is the lowest pressure in the artery and is a result of ventricular
______________. Normal DP is about _______ mmHg.
7.
Pulse pressure (PP) is the difference between ______________ pressure and ______________ pressure.
Write the equation for pulse pressure: PP = ______________
8.
Mean arterial pressure (MAP) is the calculated average pressure in the arteries. It is closer to the diastolic
pressure because the heart spends more time in ______________.
Write the equation for mean arterial pressure: MAP = ______________
9.
When taking blood pressure, inflate the cuff so that blood flow is ______________in the blood vessel.
Open the valve slowly, releasing the pressure. The first sound you hear through the stethoscope is recorded
as the ______________ pressure. The sounds you hear are due to the _________________________ of the
blood. When you don’t hear any sounds, this is recorded as the ______________ pressure.
For questions 11 and 12, calculate PP and MAP, given SP = 130 mmHg and DP = 70 mmHg.
10. PP = ___________
11. MAP = ___________
12
Answers
1.
pumping action of the heart, resistance
2.
millimeters, mmHg
3.
laminar
4.
systolic, contraction, 120
5. The dicrotic notch represents the brief backflow of blood that closes the aortic semilunar valve when the
ventricles relax.
6.
Diastolic, relaxation, 70–80
7.
systolic, diastolic, systolic pressure – diastolic pressure (SP – DP)
8.
diastole, DP + 1/3 PP
9.
occluded (stopped), systolic, turbulent flow, diastolic
10.
60 mmHg
11.
90 mmHg
13
Cardiovascular System: Factors That Affect Blood Pressure
1.
What are the three main factors that influence total peripheral resistance (TPR)?
1. _________________________
2. _________________________
3. _________________________
2.
Name three hormones that act as vasoconstrictors.
1. _________________________
2. _________________________
3. _________________________
3.
Name two hormones that directly increase blood volume.
1.
2.
4.
Track the effect on blood pressure of reducing venous return. Go through all the steps.
 VR 
5.
Categorize the following into:
A. Factors that increase blood pressure
B. Factors that decrease blood pressure
____  arterial diameter
____  total vessel length
____  vessel elasticity
____  plasma epinephrine
____  blood volume
____  plasma angiotensin
____  stroke volume
____  plasma ADH
____  blood viscosity
____  parasympathetic stimulation
____  blood volume
____  sympathetic stimulation
Use arrows in the spaces for questions 6 through 10.
6.
A  in hematocrit will result in ____ blood viscosity and ____ blood pressure.
7.
Body growth will result in ____ total vessel length and a/an ____ in blood pressure.
8.
Arteriosclerosis will result in ____ vessel elasticity and a/an ____ in blood pressure.
9.
Excessive sweating will result in a short-term ____ in blood volume and a/an ____ in blood pressure.
10.
An  in epinephrine will result in ____ vessel diameter and a/an ____ in blood pressure.
14
Answers
1. 1.
2.
3.
Vessel diameter
Blood viscosity
Total vessel length
2. 1.
2.
3.
Epinephrine
Angiotensin II
Vasopressin (ADH)
3. 1.
2.
Aldosterone
Vasopressin (ADH)
4.  VR   SV   CO   BP
5.
6.
7.
8.
9.
10.
A
A
B
B
A
B
A
A
B
B
A
A
 arterial diameter
 total vessel length
 vessel elasticity
 plasma epinephrine
 blood volume
 plasma angiotensin
 stroke volume
 plasma ADH
 blood viscosity
 parasympathetic stimulation
 blood volume
 sympathetic stimulation
, 
, 
,
, 
, 
15
Cardiovascular System: Blood Pressure Regulation
1.
a. Short-term mechanisms for regulating blood pressure include regulating what three things?
1.
2.
3.
b. Long-term mechanisms will regulate ________________________________.
2.
Two major arterial baroreceptors are located where?
__________________________________ and __________________________________
3.

Using up and down arrows, show the effect of increased blood pressure (BP) on the impulses sent to the
brain, the effect on the parasympathetic (PNS) and sympathetic (SNS) nervous systems, and the resulting
change in blood pressure.
  BP  ____ impulses  ____ PNS and ____ SNS  ____ BP
4.
As a result of these changes in the PNS and SNS, list two effects on the heart and one on blood vessels.
Heart Rate: ______________________ Cardiac Output: _____________________
Blood vessels: ____________________________
5.
As in question 3, use up and down arrows to show the effect of decreasing blood pressure.
 BP  ____ impulses  ____ PNS and ____ SNS  ____ BP
6.
In addition to effects on the heart and blood vessels, what hormones were released from the adrenal
gland? _________________________________ and _________________________________
7.
a. What cells in the kidney monitor low blood pressure? _________________
b. What enzyme is released as a result of low blood pressure? _________________
c. What does this enzyme act on in the blood? _________________
8.
Name two effects of angiotensin II.
1. _________________________
2. _________________________
9.
a. The main effect of aldosterone is: ________________________________
b. How does this increase blood volume? ________________________________
10.
a. What other hormone will increase water reabsorption from the kidney? _________________
b. What is the major stimulus for this hormone? ___________________________
16
Answers
1.
a. Short-term mechanisms:
1. Vessel diameter
2. Heart rate
3. Contractility
b. blood volume
2.
Aortic arch, carotid sinus
3.
 BP   impulses   PNS and  SNS   BP
4.
Heart
  heart rate
  cardiac output
Blood vessels  vasodilation (increased arterial diameter due to relaxation of smooth muscle)
5.
 BP   impulses   PNS and  SNS  BP
6.
Epinephrine, norepinephrine
7.
a. Juxtaglomerular
b. Renin
c. Angiotensinogen
8.
1.  Aldosterone
2. Vasoconstriction
9.
a.  Na+ reabsorption in kidney
b. Water follows Na+
10.
a. ADH
b.  in plasma osmolarity
17
Cardiovascular System: Autoregulation and Capillary Dynamics
1.
What regulates the flow of blood into true capillaries? ____________________
2.
Use arrows to show whether high or low levels of the following would cause the arterioles to dilate and the
sphincters to relax:
3.
a. O2 ________
c. pH ________
b. CO2 ________
d. nutrients ________
Physical factors also act as regulatory stimuli. How would the following affect perfusion (blood flow) of
arterioles?
a. Decreased blood pressure ____________________
b. Increased blood pressure ____________________
4.
Name two structural characteristics of capillaries that allow for passage of materials out of the capillaries.
1. _________________________
2. _________________________
5.
6.
7.
8.
9.
10.
a. Diffusion accounts for the passage of what two gases? _________________________
b. Non-lipid-soluble molecules move by _________________________.
c. Water-soluble solutes, such as amino acids and sugars, move through _________________.
Bulk fluid flows cause _____________ at the arterial end and ________________ at the venous end of the
capillary.
a. In a capillary, what is equivalent to hydrostatic pressure?
b. Why is hydrostatic pressure low in the interstitial fluid?
c. Net hydrostatic pressure tends to move fluid ______ the capillary.
a. Osmotic (or colloid osmotic) pressure in the capillaries is _____________ compared with that in the
interstitial fluid.
b. Net osmotic pressure tends to move fluid _________ the capillaries.
Given a net hydrostatic pressure of 34 mmHg and a net osmotic pressure of 22 mmHg, the force favoring
filtration would equal _____ mmHg.
Indicate which of the following move through the capillary walls by diffusion and which move through
fenestrations and/or clefts:
a. Butter:
b. Fish:
c. Cola:
d. Potatoes:
18
Answers
1. Precapillary sphincters
2. a. 
b. 
c. 
d. 
3. a. more perfusion
b. less perfusion
4. 1. fenestrations
2. clefts
5. a. O2 and CO2
b. exocytosis
c. clefts or fenestrations
6. filtration, reabsorption
7. a. Blood pressure
b. Excess fluid is picked up by lymphatics
c. out of
8. a. high
b. into
9. 12 mmHg (34 – 22)
10. a. diffusion
b. fenestrations or clefts
c. fenestrations or clefts
d. fenestrations or clefts
19