Respiratory and circulatory Flashcards
(29 cards)
problems of aquatic environment with gas exchange
- O2 low solubility in water
- (Blood has hemoglobin to help)
- increase temperature, decrease amount of O2
- saltwater holds less O2
- partial pressure– O2can have higher partial pressure in water than in air, so leaves
- more photosynthesizers–more o2
- currents mix oxegen
- depth–shallow have more 02 b.c high sa/v ratio
- rapids–splashing oxegenates water
Diffusion is insufficient for
supplying large active animals with O2 and nutrients.
- Fick’s law
- high rates of diffusion when
- A is large
- D is small
- P2-P1 is large
gills
- present a large surface area for diffusing
- countercurrent
- most of the oxygen in the incoming water has diffused into the blood
- makes fish gills efficient at extracting oxygen because it ensures a difference in partial pressure of oxygen and co2
how do vertebrates ventilate
- actively ventilate by pumpaing air via muscular contractions
- negative pressure ventilation
- diaphram creates a lower pressure within the chest cavity and causes air to flow in
cooperative binding
- binding of each successive O molecule to a subnit of hemoglobin causes conformational change in the protein that makes the remaining subunits more likely to bind to oxygen
- makes hemoglobin sensitive to changes of the PO2 in tissues
bohr shift
- decreases in pH alter hemoglobins conformation, making hemoglobin more likely to unload O2
- makes hemoglobin more likely to release oxygen during exercise where ph is high
maternal vs fetal hemoglobin
- fetal hemoglobin binds to O2 more tightly
- maternal hemoglobin facilitates transfer from mother to fetus
CO2 transfer
co2 produced by cellular respiration enters blood and reacts w/ water to form carbonic acid, dissociates into bicarbonate and H+
carbonic anhydrase
- catalyzes formation of co2 in water
- Important b/c
- protons produced by the reaction induce the bohr shift
- partial pressure of co2 drops when converted to bicarbionate ions, making a pressure gradient favoring the entryof co2 into blood
- makes CO2 uptake from tissues more efficient
most co2 is transfered in the blood as
bicarbonate
how is hemoglobin a buffer
when carbonic acid dissociates and the pH lowers, hemoglobin releases its O2 and has an affinity for protons
systematic gas exchange
- tissue fluid contains CO2
- CO2 diffuses into bloodstream
- forms into H+ and HCO3- from carbonic anhydrase
- blood ph falls, hemoglobin releases O2, H+ stick to hemoglobin and carbon dissolves to plasma as HCO3-
open circulatory system
hemolymph comes in direct contact with tissues, so molecules don’t have to diffuse across a wall of a vessel
closed circulatory system
blood flows in continuous circuit through body under pressure generated by the heart
arteries
thick walled vessels that take blood away from the heart
capillaries
thin, one cell thick, allow exchange of gases and other molecules between blood and tissues
veins
thin-walled vessels that return blood to the heart
aorta
large artery that heart ejects blood into
aquatic engironment circulation
buoyancy–gravity has less impact on blood flow
terrestrial circulation
- fight gravity to transport in elevtated portions of the body–high pressure pumping
- capillaries and alveoli to thin to withstand pressure
- separate pulmonary (low pressure) and systemic (high pressure) circulation
form=function
veins and capillaries thin-walled and arteries thick-walled
pulmonary circulation
- blood enters right atrium from body
- blood enters right ventricle (smaller muscle)
- blood pumped to lungs from right ventricle
systemic circulation
- blood returns to left atrium from lungs (through pulmonary veins)
- blood enters left ventricle
- blood pumped to body from left ventricle (big strong muscle) through aorta
