Challenge To Extreme Environment Flashcards
Which of the following is an adaptive response to prolonged exposure to microgravity during extended space travel? (select any/all that apply)
A Depression of imflammatory mediators
B Improved efficacy of gas exchange across the lung
C Increased bone mineralisation
D Increased renal salt and fluid excretion
JUST OPTION B AND D
B - V:Q is close to 1 as its no longer under the Effect of gravity
D. There is increased diuresis and naturesis because of the fluid volume imbalance, increasing pressure in brain
C - there is reduced bone mineralisation as we aren’t exercising and lack of load on bones
A Inflammatory response
what is the relationship between altitude and v02 max
and altitude and temp
for every increase in km, the v02 max drops by 10% as ppo2 drops
for every km increase after 3000m 30°C cooler
after 3000m distinct drop in Hb saturation
how can hypoxeamia be detected? how will they respond?
detected by peripheral chemoreceptors in the carotid and aortic BODIES or central chemoreceptors near the ventrolateral surface of the medulla oblongata
they will alter minute ventilation by altering the tidal Volume and frequency
also HIF to boost oxygen carrying capacity of heart
aortic arch and carotid sinus is where baroreceptors are
what is haematocrit?
it is the volume of blood cells to volume of blood
> kidney can alter fluid volume to boost the haematocrit in hypoxic environments which boost oxygen carrying capacity of blood
how does hypoxia affect the CSF in altitdue?
at altitude in hypoxia we will hyperventilate and decrease the ppC02
> no ph buffers in the CSF so it be alkaline
the chroroid plexus cells will then pump more h+ (use proton pumps) and less bicarb across BBB to restore pH in CSF
choroid plexus cells produce CSF
how is ventilation (hyper or hypo) controlled?
chemoreceptors will depolarize and release a neurotransmitter and synapse with neurons
> relay info back to central chemoreceptors by CN9 and CN10 and to the respitary centre of the medullary oblongata
nerves relay info through CNS and to the respiratory muscles to inspire/expire as respiratory muscles have no INTRINSIC RHYTHM
How are the blood gases of a free-diver likely to be altered by hyperventilating just prior to the dive? A high pp02, high ppc02 B high pp02, low ppc02 C low pp02, high ppc02 D low pp02, low ppc02
OPTION B - high oxygen, low c02
this would prevent the accumulation of Co2 in lungs and delay the next breath
what do chemoecepotrs measure?
they measure the blood gas and pH composition (pp02, ppC02, alkamlemia, acidemia)
how does altitude and hypertension relate?
altitude/ hypoxia can lead to pulmonary hypertension as there is contrcition of blood vessels away from periphery tissues to retain PPo2
also more viscous blood as there is polycythemia/ increased haematocrit
how would ethryocytosis affect physiolgixal gunctins
Polycythaemia/ erythrocytosis having a high concentration of red blood cells in your blood/ high hameotcrite
but this can make blood more viscous and more likrly to form emboli and cause stroke
heart has to pump harder to pump blood
what are HIF?
they are hypoxia inducible factors which are produced and released in the kidenys to stimulate EPPO [rodcition and boost haemtocrit/ increase oxygen carrying capactiy of the blood
they can target transcription of many genes including EPO and NO and adrenergic receptors
how does an ACE insertion allelle affect those at altidude
insertion will redcue the activity of ACE so there is less ANG11
so there will be NO dominatn activity and vasodilate = increased oxygen delivery to tissues so people are at LOW RISK OF HYPOXIA
WHAT IS THE OPTIMUM TEMP
27-42 degress
37 is best for optimum enzyme activity and best metabolic efficiency
why does a tempeature change not alter our metabolic rate>
as the heat loss by evaporation (sweat) and heat loss ffrom cinduction,convesction and radiation is matched
