Ch. 13 Regulation of Gas Transfer Flashcards
the rate of blood perfusion of the respiratory surface is related to ….
the requirements of the tissues for gas transfer
the amount of O2 delivered to the respiratory surface must equal …
the amount taken away from the blood
the ventilation to perfusion ratio in humans is
1 b/c the O2 contnet of blood is approximately that of air
the ventilation to perfusion ratio in fish is
10:1 to 20:1
water over gills:blood over gills
to compensate for a decrease in PO2 in air or water…
ventilation increases
and vice versa
why can the pattern of capillary blood flow change in gills and lungs
maintain equal blood and inhalent flow over the respiratory surface
how does hypoxic vasoconstriction of blood vessels in the lung help to maintain an ideal ventilation to perfusion ratio?
low alveolar O2 level causes vasoconstriction so blood doesnt flow to this area of the respiratory surface
neuronal regulatuion of breathing 2 types
pattern generator
rhythm generator
pattern generator
sets depth and amplitude of each breath
rhythm generator
controls breathing frequency
pre-Botzinger complex in brain stem
medullary respiratory center
sends signals to spinal motor neurons that control the diaphragm and intercostal muscles
Hering-Breuer reflex
reflex to prevent overinflation of the lungs
pulmonary stretch receptors sense over-stretching during large breaths and inhibit the vagus nerve
phrenic nerve
affects diaphragm via inspiratory neuronal activity
inspiratory neuronal activity
controls muscles of inspiration
amphibian and reptile episodic breathing
intrinsic property of brainstem
fluxes in O2 and CO2 levels in animals lead to ______ changes in ventilation
reflex
two types of receptors that affect rate and depth of breathing
carotid bodies
aortic bodies
carotid bodies and aortic bodies are ____________ that measure changes in __ and ____
chemoreceptors, O2, CO2, and pH
“central” chemoreceptors CSF
in medulla
respond to decreases in pH of CSF (high CO2) detect H+
accurate b/c no buffer system in CSF
peipheral chemoreceptors monitor
arterial blood
do peripheral chemoreceptors react to high CO2 or low pH
they think low pH, not the actual CO2 level
carotid body chemoreceptors respond greater to…
pH/CO2 changes
leads to inc ventilation via medullary resp center
increases in _____________ and _______ can also stimulate carotid chemoreceptors, and stimulation of the carotid nerve causes release of _____
temperature, osmolarity, ADH
in mammals does CO2 or O2 dominate breathing rate
CO2
in aquatic vertebrates does CO2 or O2 dominate breathing rate and why
O2
O2 is limiting in water b/c less soluble and concentration fluctuates a lot more
fish exposed to high O2…
reduce breathing until there is a high PCO2 in blood
CO2 effect on mammal pulmonary stretch receptors
reduces their inhibitory effect to increase depth of breathing and lung ventilation
lung irritant receptors
stimulation by mucous or dust causes bronchioconstriction and coughing