Frog Lab: Anatomy and Contraction Bioengineering/Physiology 3202 - - PDF document

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Frog Lab: Anatomy and Contraction Bioengineering/Physiology 3202 - - PDF document

Jan 20, 2024 678 likes •746 views

Frog Lab: Anatomy and Contraction Bioengineering/Physiology 3202 Frog Lab I Slide 1 Bioengineering 3202- Human Physiology Frog Heart Anatomy/Function Shared ventricle but blood separated Spiral fold Initial flow through

slide-1
SLIDE 1

1

Frog Lab I Slide 1

Bioengineering 3202- Human Physiology

Frog Lab: Anatomy and Contraction

Bioengineering/Physiology 3202

Frog Lab I Slide 2

Bioengineering 3202- Human Physiology

Frog Heart Anatomy/Function

  • Shared ventricle but blood

separated – Spiral fold – Initial flow through pulmonary because of reduced pressure – Resistance to flow varies with breathing (inhale reduces resistance)

slide-2
SLIDE 2

2

Frog Lab I Slide 3

Bioengineering 3202- Human Physiology

EC Coupling

  • Action potential causes influx
  • f Ca2+
  • In mammals and birds, this

causes release of more Ca2+

  • Ca2+ interacts with

actin/myosin to cause contraction

  • Pumps gather up Ca2+ or

remove it from cell

Frog Lab I Slide 4

Bioengineering 3202- Human Physiology

Regulation of Cellular Contraction

  • Adjust pretension to improve

spacing in contractile elements – Optimal spacing

  • Works at tissue and whole

heart levels

mV t Action Potential Twitch (tension) Cai transient [Ca++] gram Cai from ICa 20 40 60 80 100 120 1 1.5 2 2.5 3 3.5 4 Tension [% of maximum] Striation Spacing [µm]

Total tension Passive (rest) tension Twitch tension

slide-3
SLIDE 3

3

Frog Lab I Slide 5

Bioengineering 3202- Human Physiology

Effect of Pretension

time tension active tension isometric contraction resting tension

Frog Lab I Slide 6

Bioengineering 3202- Human Physiology

Total tension Passive (rest) tension Twitch tension

Frank Starling Mechanism

  • Increased filling

produces increased

  • utput
  • Extension of cellular

mechanism

  • Does not require

neural input

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SLIDE 4

4

Frog Lab I Slide 7

Bioengineering 3202- Human Physiology

Lab Goals/Tasks

  • Dissection of heart

– Prepare according to web site – Bring digital camera to make photos

  • Measure contraction

– Attach force transducer – Calibrate transducer – Measure contraction as function of pre-tension

Frog Lab I Slide 8

Bioengineering 3202- Human Physiology

In Situ Views

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SLIDE 5

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Frog Lab I Slide 9

Bioengineering 3202- Human Physiology

Lab Preparation