Physiology: Feedback Control - Temperature and Other Vital Signs Flashcards
normal pulse
60-100 bpm
normal blood pressure
120/80 mmHg
normal respiratory rate
12-20 breaths per min
normal temperature
36.7*C
normal cap refill time
<2 secs
normal O2 sat
> 95%
what is the core body temperature maintained at
37.8*C
normothermia
normal body temp
what does increased/decreased body temp do to cellular metabolism
increased - increases metabolism
decreased - decreases metabolism
overheating may cause
- protein denaturing
- nerve malfunction
- convulsions
- death
what are the sites for monitoring body temp
- tympanic
- rectal
- oral
what is the normal tympanic temp
35.5-37.5
what is the normal rectal temp
35.5-36.7
what affects oral temperature
food and drink
what can cause variability in body temp in general
- diurnal
- activity
- emotions
- exercise
- exposure to extreme temps
- menstration
what provides a basic level of metabolic heat and how
basal metabolic rate
oxidation of metabolic fuel from food
what can increase BMR
hormones
how does shivering affect temperature
increases heat production by increasing muscle activity
what type of fat does non-shivering themogenesis affect
brown fat
describe conduction heat exchange
heat moves between objects in contact - hot to cold
describe convection heat exchange
heat transfer by air/water currents away from the body to help carry heat away, air next to skin is warmed and rises, cooler air moves towards skin
what effect does forced air movement across skin have (i.e. wind)
increases convection/conduction, increased heat carried away
air trapping clothing increases or decreases conduction/convection
decreases
describe radiation heat exchange
electromagnetic waves strike heat into another surface , the human body both absorbs and emits this
describe evaporation heat transfer
energy converted into water i.e. vapur on skin/resp airway lining
leads to evaporative heat loss and cooling
evaporative heat loss is active/passive and is controlled by what
- active
- sympathetic nervous system
how is temperature kept constant
negative feedback
what are the effectors associated with temperature feedback loops
skeletal muscles, sweat glands, skin arterioles, behavioural adaptions
what part of the hypothalmic centre is activated by cold
posterior
what part of the hypothalmic centre is activated by heat
anterior
where does the hypothalmic centre have connections to
neural connections with imbic neurons contorlling skeletal muscles and sympathetic nervous system
what are the sympathetic responses to cold
vasoconstriction
what are the motor responses to cold
increased muscle tone, shivering and voluntary movement
what are the behavioural changes to cold
postural changes and warm clothing
what are the sympathetic changes to heat
vasodilation and sweating
what are the motor changes to heat
decreased muscle tone and voluntary movement
what are the behavioural changes to heat
cool clothing
what happens to the hypothalmic set point during fever
its raised
how do macrophages effect body temperature
they release chemicals in response to infection/inflammation and act as endogenouspyrogens
what is the role of prostaglandins in fever
they act in the thermoregulatory centre to reset the set point
draw the flow chart about fever
**
what happens to the fever flow chart if pyrogen release is reduced/stopped
prostaglandin synthesis is decreased/ceased and the hypothalmic set point is restored to normal
when the hypothalmic set point is restored to normal what is initiated
the cold response
what temperature is defined as hyperthermia and why does it happen
> 40*C
failure of heat regulating mechanisms
what temperature is defined at hypothermia and why is it bad
<35*C
below temp needed for cellular metabolism and function
