Thermoregulation Flashcards
Cutaneous Thermoreceptors
Often bimodal
-10x as many cold sensitive
—Tell us about ENVIRONMENTAL conditions
Thermoreceptors in Gut
Not just core temp, but tell about food ingested that may change body temp
Thermoreceptors in Brain
Located in pre-optic and super optic region of hypothalamus
-neuron cell bodies sensitive to change in temp
Are thermoreceptors in brain more sensitive to warm or cold?
Warm!
What part of the body detects core temp?
PreOptic and Superoptic regions of hypothalamus and viscera thermoreceptors
How is the hypothalamus the controller for body temp?
- Determines “set point” of body thermostat
- Receives info about current temp
- Decides on what to do
What is the function of the anterior hypothalamus?
Heat loss behaviors
What is the function for the posterior hypothalamus?
Heat production behaviors
Mechanisms for heat production:
ANS (sympathetic and brown adipose tissue)
Endocrine-thyroxin and EpI
Muscular activity-shivering
Non-shivering thermogenesis
-increase food intake, thyroxin for metabolic rate
How does brown adipose tissue increase heat?
Low efficiency in hydrolysis of ATP, so leads to more heat produced
Types of Heat Loss
Insensible (respiratory)
Sweating (controlled)
How does the process of sweating happen?
Sym cholinergic releases ACh which binds to muscarinic receptor
Serum is filtered into sweat gland through BV, including ions
As fluid travels up the skin surface, water and sodium are reabsorbed
Low vs High Flow Rate of Sweating
Low flow rate:
- little water (lots reabsorbed)
- high sodium (couldn’t follow water)
High flow rates
-lots of water and low sodium
What is the basis of a fever?
A fever is a controlled increase in the set point of the body by the hypothalamus
What causes the set point to increase in a fever?
Bug releases endotoxins and immune cells release cytokines
This increases prostaglandin E2, which binds to EP3 receptor and increases hypothalamic set point
