Physiology wk8

Question 1

what is a homeotherm

Answer 1

refers to humans, as we keep our body temp at around 36-37

Question 2

what are the max and min values humans can change their temp to

Answer 2

lowest = 35
highest = 40

Question 3

what is the core temp measured by

Answer 3

thsi is the temp of the hypothalamus measured by
* Oesophageal temperature
* Rectal temperature
* Stomach temperature
* Oral temperature
* Tympanic temperature

Question 4

how does shell (skin) temp vary

Answer 4

cool, warm, hot
30
30-34.9
35+

Question 5

how does temp regulation work

Answer 5

peripheral/central thermoreceptors -> hypothalamus -> messages to:
adrenal medulla
sweat glands
skin arterioles
skeletal muscles
to reduce temp

Question 6

what is the formula for heat storage

Answer 6

metabolic heat prod + convective heat loss + conductive heat loss +- radiant heat loss - evaporative heat loss

S= m ± Cv ± Cd ± r – e

Question 7

what is diff between core and skin temp regulation

Answer 7

different areas in core always gona be the same, skin varies in different areas upon the external environment

Question 8

what are the different thermoregulatory responses, cooling down and heating up

Answer 8

• Skin blood flow increased
• More sweating
• More shivering

Question 9

why is aerobic performance impaired in hot and humid environments

Answer 9

• Increased demand on heat loss mechanisms
• Reduced gradient between core and skin

less blood flow to active muscles more to skin, loss of ability to produce muscular force

Question 10

what is dehydration

Answer 10

loss of fluid from the body beyond regular levels

Question 11

what does dehydration casue

Answer 11

• Exacerbates heat stress impacts
• Decreases sweat rate and plasma volume
• Further reduces cardiac output, maximal oxygen uptake, muscle strength and work capacity

Question 12

what is hypothermia

Answer 12

when core body temps drop 2-6c, heat loss > heat production
2c – maximal shivering
4c – ataxia and apathy
6c – unconsciousness

Question 13

what are the adaptions made to the cold

Answer 13

• lower skin temp that shivering begins
• improved peripheral blood flow
• improved ability to sleep in the cold

Question 14

how does low air density effect anaerobic performance

Answer 14

offers less resistance to high-speed movement, and sprint performances are either not affected or are improved

Question 15

how does low density effect jumping

Answer 15

• Short-term anaerobic performance effects:
  lower air resistance may improve performance
• Lower PO2 at altitude should have no effect on performance (O2 transport to muscle doesn’t limit performance)

Question 16

how does low air density effect aerobic performance

Answer 16

makes it harder, less pO2

Question 17

what is boyles law

Answer 17

gas volume inversely proportional to its pressure

Question 18

what occurs to air at high altitude

Answer 18

there is the same % of gas within the air but less partial pressure. Additionally atmospheric pressure is lower at higher altitudes

same split of n/o2 but lower partial pressure

Question 19

what is hypoxia

Answer 19

low po2

Question 20

what us normoxia

Answer 20

normal po2

Question 21

what is hypoxaemia

Answer 21

low levels of o2 in blood

Question 22

what happens during hypoxia

Answer 22

reduction in arterial oxygen pressure (PaO2), this triggers neuroendocrine responses to help regulate adjustments in the physiological system.

Question 23

what are the adjustments to altitude

Answer 23

Ventilation changes:
* hyperventilation
* Raises alveolar O2
* Lowes alveolar CO2
* Causes alkalosis and diuresis (HCO-3)
Cardiovascular changes
* Increased resting HR and Q

Question 24

what happens to ventilation at higher altitude

Answer 24

increased ventilation for same wr

Question 25

what is the lactate paradox

Answer 25

Lactate production isn’t higher at altitude at maximal effort

Question 26

what is max hr like at altitude

Answer 26

Maximal hr response to exercise is attenuated at altitude, evidence that parasympathetic nervous system limits maximal hr response to exercise at altitude

Question 27

what is glycopyrrolate

Answer 27

it is a Parasympathetic blockade that restores maximal HR response to exercise at altitude

Question 28

what is ficks equation

Answer 28

vo2 = q x a-vo2 difference

Question 29

what changes occur after trainign at high altitude

Answer 29

Blood changes
* Polycythemia due to increased erythropoietin (EPO)
* O2 carrying capacity of blood normally 200 mL/litre
* Peruvians at altitude 260 mL/litre
* Extreme acclimatization 310 mL/litre
* Decreased plasma volume (helps [Hb])
* Hyperventilation causes alkalosis which shifts ODC to left,
but…..
* Increase in 2,3 DPG in RBC’s shifts ODC to right and
causes increased Bohr Shift

Question 30

what vascular changes occur after altitude training

Answer 30

• Increased capillarisation
  – in large part from reduction of muscle mass
• Increased myoglobin in muscles
• Increased aerobic enzymes (citrate synthase)
• However, muscle mitochondrial density
  probably does not increase
• a-vO2 difference during exercise, falls with
  short-term exposure, but widens following
  acclimatisation
• Increased lactate consumption and oxidation
  by active muscle