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PATH 3000 Lecture Notes - Lecture 12: Stroke, Adrenal Medulla, Hypertension

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peardeer633
22 Feb 2020
School
Dalhousie University
Department
Pathology
Course
PATH 3000
Professor
Jennifer Duncan

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Document Summary

Path 3000 lecture 12 february 3, 2020 cardiovascular diseases iii. Hypertensive heart disease: arterial blood pressure, two components, systolic normally 120 mmhg, diastolic normally 80 mmhg, determined by: Blood pressure being too high is usually referred to arterial blood pressure. The heart, the brain, the kidney, the adrenal medulla, and adrenal cortex controls blood pressure. The adrenal medulla is responsible for making the sympathetic system active. Contractility of the heart or how forceful the heart is contracting will impact the stroke volume. Increased contractility increases cardiac output to increase stroke volume. One can alter the bp physiologically for a number of reasons. Exercise leads to a greater metabolic demand and the heart will accommodate for that by beating faster and the lungs will breathe faster. Increased contractility is mediated by the sympathetic nervous system with vasoactive substances like epp and nepp to increase stoke volume. Stroke volume can also be increased through the hemorrhagic or exercise track as well.

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Related Questions

Potentially useful information: one mL = one cm3 = 10-6 m3, one mmHg = 133.3 Pa (N/m2). SV = EDV – ESV. CO = HR X SV. Ejection Fraction = SV/EDV


Hints: calculate heart rate for each condition. Remember to calculate work for the entire volume of blood that is pressurized i.e., end diastolic volume (EDV). Therefore you will need to use the data provided to calculate the EDV to answer this question.

The work done by the heart is Pressure-Volume work. While both ventricles are doing work, in this problem you will just calculate the work done by the left (high pressure) ventricle. In lecture you saw that if both pressure and volume are expressed in SI units, their product is N·m (work!) In this assignment you will calculate the work done by the left ventricle of the heart each minute to support a cardiac output of 5L/min.

1.)In a healthy person make the following assumptions: Stroke volume is 70mL and the Ejection Fraction is 58% (these are normal values). If systolic pressure is 120 mmHg, what is the work that the heart must perform each minute to produce a cardiac output of 5 L/min?

2.) Individuals with hypertension (high blood pressure) have a much greater resistance in their blood vessels and thus their heart not only has to produce greater pressure, it will have a much greater volume left following contractions (end systolic volume, ESV) Calculate the work the heart (for the identical cardiac output of 5L/min) in an individual with stage one hypertension for which these values apply: systolic blood pressure of 150 mmHg, an ejection fraction of 40% and a stroke volume of 60mL.

3.) 150mmHg is 25% greater than 120 mmHg. In this individual, how much greater is their cardiac work?

Potentially useful information: one mL = one cm3 = 10-6 m3, one mmHg = 133.3 Pa (N/m2). SV = EDV – ESV. CO = HR X SV. Ejection Fraction = SV/EDV

Hints: calculate heart rate for each condition. Remember to calculate work for the entire volume of blood that is pressurized i.e., end diastolic volume (EDV). Therefore you will need to use the data provided to calculate the EDV to answer this question.

The work done by the heart is Pressure-Volume work. While both ventricles are doing work, in this problem you will just calculate the work done by the left (high pressure) ventricle. If both pressure and volume are expressed in SI units, their product is N·m (work!) In this assignment you will calculate the work done by the left ventricle of the heart each minute to support a cardiac output of 5L/min.

B) Individuals with hypertension (high blood pressure) have a much greater resistance in their blood vessels and thus their heart not only has to produce greater pressure, it will have a much greater volume left following contractions (end systolic volume, ESV) Calculate the work the heart (for the identical cardiac output of 5L/min) in an individual with stage one hypertension for which these values apply: systolic blood pressure of 150 mmHg, an ejection fraction of 40% and a stroke volume of 60mL.

C) In this individual, how much greater is their cardiac work (@ blood pressure 150 mmHg) than a normal individual with normal blood pressure (120 mmHg)?

Please answer these questions COMPLETELY and I'll be sure to leave a "thumbs up"! Thank you!

1. Reflexes associated with Golgitendon organs prevent skeletal muscles from

a. stretching toofar

b. contracting with too muchforce

c. accumulating too much lacticacid

d. exercising toolong

2. Why do plasma glucoseconcentrations start to decline after prolonged enduranceexercise?

a. Glucagon releasedecreases.

b. Insulin releaseincreases.

c. Cortisol releasedecreases.

d. Glycogen stores aredepleted.

3. During a graded aerobic exercise,

a. SBP gradually increases while DBP remains same or slightlydecreases.

b. SBP remains same or slightly decreases while DBP graduallyincreases.

4. Factor(s) affecting blood pressure is(are)

a. HR.

b. SV.

c. Q.

d. TPR.

e. All of above.

5. Where does waterportion of sweat come from?

a. Inside of muscle cells.

b. Urine.

c. Plasma.

6. End-diastolic volume (EDV) -end-systolic volume (ESV) =

a. cardiac output(CO).

b. mean arterial pressure(MAP).

c. stroke volume(SV).

d. ejection fraction(EF).

7. The major factor affecting blood flow is

a. viscosity ofblood.

b. length of vessel.

c. radius of vessel.

d. shear stress ofvessel.

8. Accumulation of metabolicby-products in muscle (H+,CO2, heat) leads to

a. vasoconstriction.

b. vasodilation.

c. sympatheticactivation.

d. reduced muscle bloodflow.


9. During a grated exercise until the point ofventilator threshold (VT) occurring,

a. pulmonary ventilation (VE) increases proportionally to exerciseintensity increase.

b. pulmonary ventilation (VE) increases disproportionally toexercise intensity increase.

10. Immediately stopping a steady-statesubmaximal exercise, VE steeply decreases. This decrease is dueto

a. decrease in PCO2, H+, and the coretemperature (metabolic effect).

b. decrease in neural input from CNS and feedback from activemuscle.

11. During the recovery period after asteady-state submaximal exercise, VE gradually decrease because

a. decrease in PCO2, H+, and the coretemperature (metabolic effect).

b. decrease in neural input from CNS and feedback from activemuscle.

12. Valsalvamaneuver is dangerous because

a. sore abdominal muscles.

b. a drop in blood pressure if Valsalva maneuver iscontinued.

c. a dangerous rise in blood pressure immediately afterstarting Valsalva maneuver.

d. b and c are correct.

e. All of above are correct.

13. The point atwhich pulmonary ventilation (VE) increases disproportionately withoxygen consumption (VO2) during graded exercise iscalled

a. ventilatory threshold (VT).

b. lactate threshold (LT).

c. anaerobic threshold (AT).

14. Which condition duringexercise induces the right shift of hemoglobin's oxygen-binding affinity curve(Bohr effect)?

a. ADP accumulation

b. lower pH

c. mechanical compression ofmuscle capillaries

d. local hypoxia(low O2)

15. How is bloodpressure response during submaximal exercise different between armsand legs?

a. Arms have a higher.

b. Legs have a higher.

c. They are the same

d. They can't be compared

16. Which of thefollowing does not increase the heart'sstroke volume?

a. Enhanced cardiac filling and ejection

b. Neurohormonal influence

c. Training adaptations that expand blood volume

d. Training adaptations that increase resistance to bloodflow

17. Which of the following willdecrease stroke volume (SV)?

a. increased preload

b. increasedcontractility

c. increased Calcium(Ca2+) concentrations

d. increasedafterload

18. For two athletes with sameVO2max, An athlete who has _____ lactate thresholdpredicts better performance.

a. higher

b. lower

c. It doesn