lec 9 lab 8 - diving Flashcards
what are the adaptations of marine animals when diving (eg. oxygen stores, circulatory adjustments)
large oxygen stores
- large blood oxygen - high o2 carrying capacity, high hematocrit and blood volumes compared to non divers
- muscle oxygen stores - high myoglobin concentrations (used as muscle oxygen store) → humans (4-9 mg myo/g) vs diving animals (55-70 mg myo/g) they are also tolerant to lactate buildup from anaerobic metabolism
avoiding decompression sickness
circulatory adjustments
- reserve oxygen supply to tissues that need it most (brain and heart)
- higher affinity hemoglobin
reduce metabolic costs during diving
Compare and contrast the oxygen stores between diving and non-diving mammals.
diving has greater o2 carrying capacity, blood volume per kg and max blood store (the two previous multiplied)
marine mammals can deplete oxygen stores to almost 0
lung volume decreases as ambient pressure increases
- thorax and lungs become tiny the deeper they are
they have small lungs because:
otherwise they’d float (buoyant), the alveoli would collapse under high pressure so bye bye gas exchange and have a large store of N2 leading to decompression sickness
Describe how changes in blood flow allow diving mammals to perform long dive.
heart rate decreases to maintain arterial blood pressure
- arterial blood pressure depends on cardiac output and vascular resistance (during vasoconstriction, SNS cutting off blood flow to abdominal organs)
vasoconstriction divides body into…
- tissues with no blood flow (o2 myoglobin → anaerobic glycolysis → lactate accumulation)
- tissues with blood flow (remain aerobic)
what are the reducing metabolic costs
tissue cooling, delay in food processing, reducing cost of swimming (gliding)
bradycardia
significant reduction in heart rate
depolarization = _________, repolarization = __________
contract, relax
