Frog Lab Slide 1 Bioengineering 6000- Systems Physiology

Leftovers

Bioengineering/Physiology 6000

Frog Lab Slide 2 Bioengineering 6000- Systems Physiology

Altitude and Pulmonary Edema

• At sea level, reduced oxygen concentration comes from restricted air flow and capillaries constrict to increase flow in unrestricted airways

• At altitude, reduced oxygen concentration is widespread but the resulting capillary constriction is uneven

• Result is increase pressure in some alveolae and edema

• Edema is patchy but still very dangerous

Frog Lab Slide 3 Bioengineering 6000- Systems Physiology

Comments on Anatomy Lab

Bioengineering/Physiology 6000

Frog Lab Slide 4 Bioengineering 6000- Systems Physiology

Comments• Structure;

– Intro/overview– Methods– Results and observations– Discussion

• Writing– Clear, concise, factual– Careful wording for accuracy– Facts over opinion

• Preparation– Figures and captions– Incorporate figures and tables in the text– All measurements in SI system

Frog Lab Slide 5 Bioengineering 6000- Systems Physiology

Frog Lab: Control of the Heart

Bioengineering/Physiology 6000

Frog Lab Slide 6 Bioengineering 6000- Systems Physiology

Regulation of Heart Rate

SA Node

ACh

ACh: • increases pK

• reduces If

(muscarinic receptor)

Epi,NE

Epi/NE; • increases If

(1-adrenergic receptor)

Frog Lab Slide 7 Bioengineering 6000- Systems Physiology

Regulation of Cardiac Contractility• Increase in amplitude or rate of

rise of isometric tension at fixed length,

• Free [Ca+2]i is key component• Positive inotropic agents:

– epinephrine: stimulate receptors and increase Ca+2 influx and uptake (load SR)

– Caffeine: increases sensitivity of myofilaments and causes release of SR Ca+2

• Negative inotropic agents:– ACh: acts mostly on atria to

shorten AP and reduce [Ca+2]i – Cadmium: resembles Ca+2

enough to block channel

Mus

cle

tens

ion

Passive (rest) tension

Total tension

Twitch tension

Muscle length

Effect of NE/E

Frog Lab Slide 8 Bioengineering 6000- Systems Physiology

Effect of E/NE on Contraction

• constant pretension• reduced shortening

(limited by max tension curve)

• reduced stroke volume

1

2

3

4

tens

ion

[g]

muscle length

maximum isotonic tension

Pre

ssur

e

Volume

Left Ventricle

strokevolume

Frog Lab Slide 9 Bioengineering 6000- Systems Physiology

Amphibians (e.g., Frog)

• Shared ventricle but blood separated

– Spiral fold

– Initial flow through pulmonary because of reduced pressure

– Resistance to flow varies with breathing (inhale reduces resistance)

Frog Lab Slide 10 Bioengineering 6000- Systems Physiology

Lab Interventions

• Cold Ringer’s solution• ACh• Epinephrine• Isoproterenol • Ca2+-free solution• Caffeine• Cadmium chloride• Potassium chloride

Frog Lab Slide 11 Bioengineering 6000- Systems Physiology

Midterm

Bioengineering/Physiology 6000

Frog Lab Slide 12 Bioengineering 6000- Systems Physiology

Midterm Information

• See web site for study topics• Format:

– True/false– Short essay– Closed book

• Try and start on time