Fluid and caval rupture solve 3 ways 1 empty lungs

fluid, and caval rupture
- Solve 3 ways:
1. Empty lungs before diving
2. Cut off blood entirely to lungs (No circulation)
3. Lungs collapse
- Dolphins have hinged ribs and lungs not firmly attached so they can “squish”
- Turtles don’t have a collapsible chest, so they swim shallow, but leatherbacks may have a flexible
shell
- Sinuses lined with bone (vascular rete): nothing to collapse with a bony covering, but can fill with
blood supply, vessels swell with H2O and equalize the pressure, so the bones don’t crush
- Air must go somewhere: it is stored in airways (bronchioles and trachea), air under pressure
wont go into the bloodstream, cant be crushed under pressure because they have flexible
cartilage rings in airways  reinforced airways increase tidal flow without collapse
High Pressure Nervous Syndrome
- Pressure affects neural transmission, leading to transmission errors and misfunctioning of brain
stem

EXAM 3 REVIEW
Metabolism
- The sum of all chemical reactions in all cells
- Anabolism + Catabolism
Metabolic Rate
- Energy expenditure/time (kcal/hr)
- MR = aW
b
a = MR/unit mass, W = body mass, b = slope
- Measured in 3 ways:
1. Calculate change in energy in vs out
2. Determine total heat output of animal (calories in vs out)
3. Measure O2 consumption (because O2 is final electron acceptor)
- Basal Metabolic Rate (endotherms): MR at physical rest, several hours after eating, in the
thermoneutral zone (TNZ = room temp)
- Standard Metabolic Rate (ectotherms): MR adjusted by environmental temps, varies
- BMR and SMR increase when thyroid hormones increase
Specific Dynamic Action (SDA)
- Diet-induced thermogenesis (DIT)
- An increase in MR above BMR/SMR levels after food intake
- Lasts days for ectotherms and hours for endotherms
Temperature Largely Effects Metabolism
- Increased temps denature enzymes
- Homeotherms: have one usual set internal temperature (stable)
- Endotherms: produce their own heat
- Vasoconstrict @ skin temp=environmental temp
- Vasodilate @ skin temp between core-environment temps
- Poikilotherms: alternate internal temps, compensate by changing enzyme [ ] , homeo-viscous
membrane, and pH regulation
- Ectotherms: get heat from environment
- Membranes
o @ low temps = high viscosity and rigid (low saturation)
o @ high temps = low viscosity and fluid (high saturation)
SA:V Ratios
- SA related to squared, volume related to cubed
- Small animals have a greater SA:V ratio
- Heat is produces as a function of Volume
- Heat is lost as a function of SA (by skin)
- Increased MR = decreased mass/body size = decreased muscular activity (small size = high MR)

EXAM 3 REVIEW
Specific O2 Consumption: MR/gram tissue
Heat Production
1. Basal MR (endotherms)
o thyroid regulates # of Na/K pumps
2. Sympathetic Nervous stimulation
o Non-shivering thermogenesis of Brown Adipose Tissue (BAT): Cold temp or diet
stimulate a nerve to release Norepinephrine, thermogenin opens and allows H+ to
pass through inner mitochondrial membrane = dissipates H+ gradient as heat
without making ATP
o Ghrelin may suppress BAT
3. Thyroxine (Hormones)
o Increased when cold (hypothyroid), lowers MR
4. Shivering (Muscular activity)
5. SDA/DIT (Digestion)
6.