1. REVIEW SLIDES

2. NOTE:
Disclaimer: students may find typos/mistakes in these reviews. If you spot them, please feel free to make a change and then the instructor the corrected Power Point.
Disclaimer: these slides are not intended to substitute for exam preparation. Finding a mistake does not exempt students from knowing the material.

3. Cardiac Output, Blood Flow and Blood Pressure
Chapter 14
Cardiac Output, Blood Flow and Blood Pressure

4. How does the proximity of Ca2+ channels affect the rates of contraction of skeletal muscle versus cardiac muscle?

5. How does the proximity of Ca2+ channels affect the rates of contraction of skeletal muscle versus cardiac muscle?
The close proximity of calcium channels in the plasma membrane and SR membrane in skeletal muscle ensures a faster contraction than in cardiac muscle where the channels are not directly coupled.

6. Describe the Frank-Starling Law of the heart

7. Frank-Starling Law of the Heart
OTTO FRANK
ERNEST STARLING
Increased EDV results in increased contractility and thus increased stroke volume.

8. Describe ANP

9. Describe ANP
A hormone released by the left atrium in response to increased blood pressure
Lowers bp
Lowers blood volume  how?
Secreted by atrium

10. The stroke volume is regulated by three variables
The stroke volume is regulated by three variables. See if you can name them!

11. Regulation of Stroke Volume
Regulated by three variables:
End diastolic volume (EDV): volume of blood in the ventricles at the end of diastole
Sometimes called preload
Stroke volume increases with increased EDV.
Total peripheral resistance: Frictional resistance in the arteries
Inversely related to stroke volume
Called afterload
Contractility: strength of ventricular contraction
Stroke volume increases with contractility

12. What factors affect the total peripheral (vascular) resistance?

13. What factors affect the total peripheral (vascular) resistance?
Arterioles have high vascular resistance at rest due to alpha-adrenergic sympathetic stimulation
However, even at rest, skeletal muscles still receive 20−25% of the body’s blood supply.
Blood flow decreases to skeletal muscle during contraction and can stop completely beyond 70% of maximum contraction.
Vasodilation is stimulated by both adrenal epinephrine and sympathetic acetylcholine.
Intrinsic metabolic controls enhance vasodilation during exercise

14. Net Filtration Pressure
Describe net filtration pressure and how to calculate it.

15. Net Filtration Pressure
Net filtration pressure is the hydrostatic pressure of the blood in the capillaries minus the hydrostatic pressure of the fluid outside the capillaries
Hydrostatic pressure at arteriole end is 37 mmHg and at the venule end is 17 mmHg
Hydrostatic pressure of interstitial fluid is 1 mmHg
Net filtration pressure is 36 mmHg at arteriole end and 16 mmHg at venule end

16. What is an inotrope?

17. What is an inotrope?
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term inotropic state is most commonly used in reference to various drugs that affect the strength of contraction of heart muscle. However, it can also refer to pathological conditions.

18. Name five factors affecting venous return.

19. Factors in Venous Return
Pressure difference b/w vena cava (0 mmHg) and venules (10 mmHg)
Sympathetic nerve activity to stimulate smooth muscle contraction in venous walls
Skeletal muscle pumps
Pressure difference between abdominal and thoracic cavities (respiration)
Blood volume

20. Describe cardiac output

21. cardiac output = stroke volume X heart rate
Cardiac output – the volume of blood pumped each minute by each ventricle:
cardiac output = stroke volume X heart rate
(ml/minute) (ml/beat) (beats/min)
Average heart rate = 70 bpm
Average stroke volume = 70−80 ml/beat
Average cardiac output = 5,500 ml/minute

22. What is the pulse pressure?

23. What is the pulse pressure?
The pulse pressure is the pressure of the pulse.
It is the difference between the diastolic and systolic levels of the heart. It is the force of the difference through the artery
To calculate it, subtract the diastolic from the systolic pressure

24. Frank-Starling Law of the Heart
How does this compare with contractility of skeletal muscle?

25. Frank-Starling Law of the Heart
How does this compare with contractility of skeletal muscle?
This shows that the more the heart
is stretched, the greater it’s contractility
but the more that skeletal muscle is stretched, the less contractile
strength it will have.

26. How does the hormone aldosterone affect blood volume?

27. How does the hormone aldosterone affect blood volume
How does the hormone aldosterone affect blood volume? Aldosterone raises blood volume and raises blood pressure.

28. Aldosterone is secreted from

29. Aldosterone is secreted from adrenal cortex

30. How does atrial natriuretic peptide affect blood volume?

31. How does atrial natriuretic peptide affect blood volume?
Reduces blood volume (lowers blood pressure by signaling kidneys to expel Na+).

32. Does this picture represent intrinsic or extrinsic control of the heart?

33. Does this picture represent intrinsic or extrinsic control of the heart? INTRINSIC

34. Describe the Frank-Starling Law of the Heart
(Fig. 14.2, 14.3 and 14.4 and associated text).
OTTO FRANK
ERNEST STARLING

35. Frank-Starling Law of the Heart
Frank-Starling Law of the heart says:
“Increased End Diastolic Volume (EDV) results in increased contractility and thus increased stroke volume.”
This is a built-in or “intrinsic” property of the heart.

36. What is ANP? What is the effect of ANP and describe its negative feedback loop.
Also – what is the relationship between ANP and ADH?

37. Fig. 14.13 Atrial natriuretic peptide: Natrium = sodium
Uresis = making water natriuresis = excreting water with salt
Fig

38. Describe calcium-induced calcium release and its purpose.
AKA: calcium-stimulated calcium release.

39. Describe calcium-induced calcium release and its purpose.
AKA: calcium-stimulated calcium release.
Membrane depolarization causes Ca2+ channels in the sarcolemma to open;
The influx of Ca2+ into the cell causes Ca2+ to be released from the sarcoplasmic reticulum into the sarcoplasm.
Ca2+ then binds to troponin and stimulate muscle contraction.
This happens in both heart muscle and skeletal muscle

40. DESCRIBE the baroreceptor reflex.

41. DESCRIBE the baroreceptor reflex
Baroreceptors are located in the aortic arch and carotid sinuses
They detect blood pressure by stretching of their walls, increasing action potentials sent through sensory nerve fibers to the medulla oblongata (vasomotor control center and cardiac control center)
Vasomotor control center – alters vasoconstriction
Cardiac control center – alters heart rate

42. A sphygmomanometer measures

43. A sphygmomanometer measures blood pressure

44. Explain how lowered blood pressure affects renin, angiotensin and aldosterone

45. Fig