Homeostasis Flashcards
What are the two responsibilities of homeostasis?
- Maintain constant + normal internal environment
- Coordinate response between systems to compensate for environmental changes
What is a homeotherm?
Animal that is able to generate + dissipate their own heat
What is the difference between the core body + outer shell?
Core Body - protects vital organs + important for survival
Outer Shell - buffer zone between outside + core
What does the thermoneutral zone represent?
Environmental temperature where the core temperature is maintained
What happens to the cardiovascular + respiratory system in hypothermia?
Blood circulation + respiration fail
Blood thickens + oxygen delivery decreases
What happens in hyperthermia to cell function? Why does this happen?
Cells stop functioning as enzymes + protein denature at high temperatures
What three processes/activities help animals produce their own heat? Is it an endothermic or exothermic process?
- Metabolism
- Growth + Production
- Exercise
Endothermic + Inefficient
What 4 methods release heat into the environment. Describe each.
- Radiation - object with lower radiation absorbs radiation from greater source
- Conduction - heat transported through contact
- Convection - heat transported using water/air
- Evaporation - breakdown of water molecules using energy to transport heat
When exposed to cold, what is the body’s automatic response to generate heat?
Shivering
What two systems are involved in non-shivering thermogenesis? What biological process increases?
Sympathetic NS + Endocrine (Thyroid hormones)
Metabolism increases
How does the sympathetic NS increase heat production in non-shivering thermogenesis?
releases adrenalin + calorigenic effect from brown fat produces heat
How does the endocrine system produce heat in non-shivering thermogenesis?
Thyroid hormones are released in order to increase the BMR response
What is the difference between vasodilation + vasoconstriction in the process of heat transport?
Vasodilation - promotes heat loss
Vasoconstriction - prevents heat loss
What are 4 methods of evaporation?
- Passive evaporation
- Sweating
- Panting
- Bathing
What system is involved in sweating? What is the consequence of sweating?
- Sympathetic NS
- Lose ions
The reflex response follows what path to produce a response?
Sensor –> Integration Center –> Effectors
Describe the reflex response.
- thermoreceptors sense change in temperature
- hypothalamus compares sensory information to internal references
- activated effectors return temperature to normal range using sympathetic NS, shivering, and hormones
Explain the voluntary component of thermoregulation?
- hypothalamus exchanges information with the cerebral cortex
- the cerebral cortex causes a behavioural response (ex. put on a coat when cold)
Where are heat receptors located?
- Skin below epidermis
- Body core
- Blood vessels
- Viscera
What is the difference between peripheral + central thermoreceptors?
Peripheral - located under the skin
Central - located in the brain
Explain process of heat loss when skin temperature increases.
- Increase skin + core temperature
- Peripheral + central thermoreceptors detect heat increase
- Sensory information sent to hypothalamus
Effects to increase heat loss:
- Respiratory rate increases
- Sweat glands increase sweat production
- vasodilation increases (vasoconstriction decreases) to increase skin blood flow
Where is the heat-loss center in the hypothalamus located in response to heat?
Anterior hypothalamus
What are other effectors to heat loss besides vasodilation + increased respiratory rate?
- behavioural responses (seek shade)
-decreased physical activity
Explain process of heat production when skin temperature decreases.
- Decrease skin + core temperature
- Peripheral + central thermoreceptors detect heat increase
- Sensory information sent to hypothalamus
Effects to increase heat loss:
- Shivering
- hormones released to increase metabolism
- vasoconstriction increases to decrease blood flow
