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thermoregulation in humans - Coggle Diagram
thermoregulation in humans
new borns
while in uterus, many of the physiological processes of a fetus are supported by the mother.
once delivered the new born must function independently
several physical and physiological features of new born babies prevent them from fully regulating their body temperature until 6 months of age
they require a number of significant physiological changes, including those associated thermoregultion.
new borns can not shiver to produce heat and have limited capacity to generate heat from lager body movements( as they have limmited movement)
the head is very large compared to the rest of the body therefore the loss of heat comes from the head
skin
The skin is made of two layers.the outer layer is made up of layers of simple cells that protect the deeper cell layers from wear and tear
The skin plays an important part in regulating body temp due to its large surface area from which heat from the environment is gained or lost
The lower dermis contains the skins sensory receptors and hairs.
thermoreceptors
(free nerve ending) in the dermis detect changes in skin temperature and send verve impulses to the hypothalamus, which mediates an appropriate
the skin provides a large surface area for heat loss or gain
hypothermia
moderate hypothermia
muscle coordination becomes difficult. movements slow or laboured. blood vessels in ears, nose fingers and toes constrict further resulting in these turning a blue colour. mental confusion sets in
severe hypothermia
speech fails. mental processes become irrational, victim may enter a stupor. organs and heart eventually fail resulting death
mild hypothermia
shivering. Vasoconstrtiction reduces blood flow to the extremities. hypertension (high blood pressure) and cold diuresis (increased urine production due to the cold)
hyperthermia
phase 2
heat exhaustion
is a more serious problem. it is indicated by profuse sweating ,dry mouth ,cramp and nausea. the skin will appear red as blood is directed to the skin to reduce core temp. physical activity should be stopped immediately and shade should be sought. cool drinks and ice pack on skin may be needed
phase 3
heat stroke
is the final and most serious stage. the bodys core temp may have risen to 41 degrees. thermoregulatory mechanisms fail. sweat is no longer produced and the skin becomes hot and dry, disorientation is followed by collapse and unconsciousness. metabolic processes become uncoupled and enzymes denature. death follows
phase 1
overexertion
is usually accompanied with a flushed red face and rapid short breaths.
in humans, the temperature regulation centre is in the hypothalamus. thermoregulation relies on negative feedback mechanisms and involves several body systems
the hypothalamus responds directly to changes in the core temperature and to nerve impulses from receptors in the skin
body temp
42 degrees is hyperthermia
35 degrees is hypothermia
36.7 -37 is average body temp (healthy)
fever
fever is an important defence against infection, but if the body temp rises over 42 degrees
a dangerous postive feedback loop can begin, making the body produce heat faster than it can get rid of
the blood vessels beneath the surface constrict to reduce blood flow or dilate to increase the blood flow
hypothermia (low body temp)occurs when the body cannot thermoregulate effctively, and core body temp drops below 35 degrees
hypothermia is casued by exposure to low temperatures and results from the bodys inability to replace the heat being lost to the environment
hyperthermia (high body temp) occurs when the body cannot thermoregulate properly and the core body temp rises over 38.5 degees