Chapter 5 Flashcards
What is thermoregulation
The regulation of body temperature
What is body’s constant temperature
36.8
What temperature is optimal for cellular respiration
37 degree Celsius
What does the core of the human body include
Organs of the thorax and the abdomen and the head.
Vital organs
Heat gain
Absorbing heat from external environment and cellular metabolism
What maintains out higher internal body temperature compared to the environment
Heat from cellular metabolism helps to maintain
What temperature should the body not exceed even whilst during excessive or sports
36.8 degree Celsius
What are the heat gained from environment
Conduction and radiation
How do we lose heat
Radiation-radiant heat emitted from body
conduction - loss of heat from. 2 surface
and evaporation of water, moisture from lungs, warm urine and feaces
Convection- gas current or liquid current
What are thernoreceptor
Detect temperature of internal envirmonent,
Peripheral thermoreceptor are located in skin and mucous membrane
Central thermoreceptor are located in the hypothalamus
Types of thermoreceptor
Cold thermoreceptor- stimulated by temperature lower than normal
Heat thermoreceptor - stimulated by temperature higher than normal.
Blood vessel and heat loss
Blood vessels close to the dermis of the skin carry heat from the core to the skin.
The diameter of blood vessels are controlled by autonomic nerves
What causes and happens in vasodilation
In hot temperatures, vasodilation occurs which increases the diameter, causing more blood to the skin and therefore more heat is lost.
What causes and happens during vasoconstriction.
When cold temperatures, the diameter of blood vessels decreases, causing less blood to the skin leading to less loss of heat.
When does sweating occur and what is Sweating
When large amount of heat must be lost and blood vessels are fully dialated sweating must occur.
Sweating is a process of the active secretion of fluid by the sweat gland and the periodic contraction of cells surrounding the ducts to pump sweat to the skin surface.
It is stimulated by sympathetic nerves
What happens to the sweat evaporated
Heat is taken away when liquid turns to vapour and has a cooling effeccf
What is shivering
An increase in skeletal muscle tone, producing rhythmic muscle tremors that occurs at a rate of 10-20per sec.
What are 5 mechanism for Preventing body temperature from falling
If outside environment falls in temperature, the cold receptors in our skin sends message to the hypothalamus.
The hypothalamus then triggers,
1- vasoconstriction of arterioles in skin leads to decrease blood flow of warm blood to skin which leads to reduce in transfer of heat from internal body to organs to skin which leads to skin becoming more cooler and therefore less heat is lost through radiation,
2- stimulation of adrenal medulla- they secrete noradrenaline and adrenaline which increases cellular metabolism leading no increased heat production
3- shivering- increases heat production
4- increased secretion of throxine via the anterior pituitary gland which increases metabolic rate, which increases heat production leading to increased body temperature.
5- behavioural response - having conscious awareness of cold condition, we behave in a way to reduce heat loss. Eg- putting clothes on
What are the mechanisms of preventing body temperature from rising
Hypothalamus triggers
1- vasodilation of skin arterioles- increases blood flow to skin which increases the surface temperature and therefore more heat is lost through radiation and convection
2- sympathetic nervous stimulation -causes sweating which leads to the evaporation of heat.
Sweating occurs from. 28 degree Celsius.( radiation, conduction,convection, evaporation.)
One environmental temperature exceeds 37 degree Celsius, only heat loss through evaporation such as sweating is effective.
3- reduction of metabolic rate- hypothalamus triggers the tshif, which inhibits the secretion of tsh in the anterior pituitary galnd which leads to the decrease in the secretion of thyroxine which decreases the rate of cellular metabolism which leads to decreased heat production. “Slow process “
4) behavioural response- turning on fan or air conditioner, removal of external clothing and reducing physical activity.
Percentage of extra cellular and intracellular fluid.
Intracellular-(66%)
Extra cellular-(33%)
Osmotic concentration
The concentration of solutes
