Biology 272a: Comparative Animal Physiology - PowerPoint PPT Presentation

About This Presentation
Title:

Biology 272a: Comparative Animal Physiology

Description:

... an extreme diving response. The seal didn't know how long it ... Harbor seal breathing air. 0.5 s. 2 s. 6 s. Fully perfused kidney and other viceral organs ... – PowerPoint PPT presentation

Number of Views:224
Avg rating:3.0/5.0
Slides: 25
Provided by: brentsi
Category:

less

Transcript and Presenter's Notes

Title: Biology 272a: Comparative Animal Physiology


1
Biology 272a Comparative Animal Physiology
  • Diving mammals

2
Dive record of a male northern elephant seal
Fig. 25.4
3
Dive durations of Weddell seals
Fig. 25.1a
4
Problems with diving
  • Oxygen
  • Nitrogen
  • Waste products
  • CO2
  • Lactate

5
Forced diving
  • Led to an extreme diving response
  • The seal didnt know how long it would be
    underwater!

6
Natural Diving
7
Natural diving
8
The classical diving response
  • Apnoea
  • Bradycardia
  • Vasoconstriction and reduced blood flow

9
Oxygen
  • or lack thereof

Blood lactate
Aerobic dive limit
Fig 25.12
10
Oxygen stores
Fig. 25.6
11
Conserving oxygen
  • Peripheral vasoconstriction
  • Hypoperfusion of viceral organs
  • Brain retina remain normoxic

12
Body and heart-lung-brain become separate
compartments
Blood O2 remains high
Muscle O2 depleted
Fig. 25.10a
13
Harbor seal breathing air
2 s
6 s
0.5 s
Fully perfused kidney and other viceral organs
Fig. 25.7 a-c
14
Harbor seal in forced dive
2 s
6 s
0.5 s
Breathing Air
No perfusion of kidney and other viceral organs
Fig. 25.7 d-e
15
Waste products CO2
  • High blood buffering capacity
  • Reduced changes in blood pH
  • Reduced ventilatory response to CO2
  • Or increased threshold
  • Post-dive hyperventilation

16
Waste products - lactate
Anaerobic metabolism is compartmentalised
Fig. 25.10b
17
Waste products - lactate
Fig. 25.11
18
The Bends
  • Workers in pressurised mine shafts and tunneling
    projects in 19th C
  • Caisson disease
  • PN2 (lungs) gt PN2 (blood tissue)
  • results in increased N2 in tissues and fluids
  • Rapid decompression results in N2 coming out of
    solution
  • Bubbles of N2 gas in joints cause the bends
  • Other symptoms also due to bubbles and/or high
    N2

19
Why dont seals get the bends?
Air is compressed out of gas exchange surfaces,
so N2 cant diffuse into bloodstream but nor can
O2
Fig. 25.5
Compressible thorax
Fig. 24.14
20
Compressed alveoli an oxygen supply for
resurfacing?
Decreasing depth and pressure
More O2 becomes available during ascent
21
Gradations of the diving response
Fig. 25.1
Fig. 25.2
22
Gradations of the diving response
Fig. 25. 9
23
The classical diving response
  • Apnoea
  • Bradycardia
  • Vasoconstriction and reduced blood flow

24
Thats it!
  • See you Thursday for the review session
  • Fun (ie non-examinable) lecture about my
    research next Tuesday.
Write a Comment
User Comments (0)
About PowerShow.com