Overview of 3 main Chapter 19 themes A

Overview of 3 main Chapter 19 themes: (A) bulk flow in vessels, (B) filtration, (C) diffusion 4 th theme (less related to this figure): blood pressure and its regulation https: //oli. cmu. edu/jcourse/workbook/activity/page? context=b 880 f 0 e 680020 ca 600 d 4 ead 572 bb 0410 1

Ch. 19: Test Question Templates • Q 1. Given an anatomical change/different relating to a variable in the Fick or Poiseuille equations, explain how this change/difference changes the diffusive flow or bulk flow. • Example. Which is greater, diffusion of O 2 out of the brachial artery into surrounding muscles, or diffusion of O 2 out of the capillaries that serve these muscles? Explain in terms of the Fick equation. • Q 2. Given a change in a variable that affects HPc, OPc, HPif, or OPif, say whether this change increases the risk of edema. • Example. Heart rate increases. (Everything else stays the same. ) • Q 3. Given a figure such as Marieb & Hoehn Figure 19. 15, answer a question about the control of blood flow. • Example. Based on Figure 19. 15, do you think cutaneous arterioles have alpha-adrenergic receptors or beta-adrenergic receptors or neither? Explain. 2

Flow Down Gradients: Diffusion and Bulk Flow rate? Gradient that drives the flow? Poiseuille’s law Fick’s law Figure: J. Michael et al. (2017), The Core Concepts of Physiology 3

Bulk flow in blood vessels: Poiseuille’s Law http: //www. physics. usyd. edu. au/teaching/Ag/Transfer/TPpoiseuille. html 4

How the various factors in the Poiseuille equation affect flow Impact on flow if this factor ↑ Factor Example of this factor ↑ P 1 (pressure) ↑ cardiac output η (viscosity) ↑ hematocrit r (radius) Vasodilation L (vessel length) Surgical change to vessel π (pi) God destroys the universe and starts over? Never mind… 5

Filtration through capillary walls: hydrostatic & osmotic pressures Q 1. What is hydrostatic pressure (HP)? Q 2. What is osmotic pressure (OP)? Q 3. Will the capillaries have both HP (HPc) and OP (OPc)? Q 4. Will the interstitial fluid have both HP (HPif) and OP (OPif)? https: //oli. cmu. edu/jcourse/workbook/activity/page? context=b 880 f 0 e 680020 ca 600 d 4 ead 572 bb 0410 6

Marieb & Hoehn (2019), Focus Figure 19. 1 7

Marieb & Hoehn (2019), Focus Figure 19. 1 8

Q 1. Overall, from the beginning of the capillary to the end, is there a net filtration of fluid into the interstitial fluid, or a net reabsorption into the capillary, or a net change of 0? Q 2. If/when there is net movement of fluid, where does that fluid go? Q 3. What is edema? Now consider possible causes of edema, based on the various pressures involved. Q 4. Would a liver disease that impairs production of plasma proteins increase the risk of edema? Why or why not? 9

Diffusion across cell membranes: Fick’s Law of Diffusion C 1 C 2 A= e c a f r u s area k = a “constant” (depends on solute, solvent, etc. ) d = thickness of diffusion barrier

Q 1. Which way will these molecules diffuse at the “tissues” (e. g. , skeletal muscles)? Will each use simple diffusion, facilitated diffusion, or active transport? Diffusion at skeletal muscles a. O 2 b. CO 2 c. glucose Q 2. Does much diffusion occur through arterial walls? Why or why not? Martini et al. (2015), Figure 23 -18 11

Blood pressure (BP) and its regulation Q 1. Fill in the labels: • Systolic pressure • Diastolic pressure • Mean pressure Q 2. Where are the main baroreceptors for monitoring BP? Q 3. Which pressure(s) must be regulated homeostatically? • Arterial? • Capillary? • Venous? Marieb & Hoehn (2019), Figure 19. 7 12

How is (arterial) BP regulated? Basically, you can change 3 things: Q 1. Which of these can be adjusted QUICKLY (within seconds)? Q 2. Which of these must be adjusted SLOWLY (over hours/days)? Clip art from livestrong. com and clipartbarn. com 13

Maintaining BP during exercise Muscle vessels are dilated to increase O 2 delivery and CO 2 removal. Q 1. Why do we need to vasoconstrict other vessels? Q 2. How does the sympathetic nervous system coordinate these vasodilations and vasoconstrictions? (Hint: think about adrenergic receptor subtypes!) Marieb & Hoehn (2019), Figure 19. 15 14

This diagram illustrates the regulation of blood pressure. As usual, the teetertotter represents homeostatic control (BP shouldn’t be too high OR too low). Q 1. What is the little yellow thing? Q 2. Which parts of the brain serve as the control center? Q 3. What are the effects on the heart and arterioles in each case? Q 4. What specific branch of the nervous system makes these adjustments? Marieb & Hoehn (2019), Figure 19. 11 15

BP regulation: SLOWER adjustment: • Antidiuretic hormone (ADH) from _______ • Erythropoietin (epo) from _______ • Aldosterone from ________ • Angiotensinogen from ________ Q 1. Are these nervous system or endocrine system adjustments? Q 2. How does each affect blood volume? 16

Q 3. Why is hemorrhage a challenge to BP regulation? Q 4. How will the body respond (short-term)? Q 5. How will the medical staff respond (short-term)? Q 6. Why might fainting help? wisegeekhealth. com/what-is-fainting. htm 17

Ch. 19: Additional resources • Pearson Mastering has a good Interactive Physiology segment on this. • IP 2: Factors Affecting Blood Pressure • Other suggestions? Let me know! 18

Answer key for Suggested Lecture Outline file • You should already have access to answers to some of the questions (Check Your Understanding, online Practice Quiz, online Practice Test) • Answers to pre-lecture questions and end-of-chapter Review Questions will be in the Presenter Notes that accompany this slide. 19