Week 12 Thermoregulation Flashcards
Negative feedback system
Negative feedback - means that the stimulas (rising heat) has been negated.
Oscillation
In a system controlled by negative feedback the variable is never maintained perfectly but
-Constantly oscillates about the set point
Definition: movement back and forth in a regular rhythm
What does CNS mean
Central integrating centre
physiological feedback systems
- Signals are sent to effectors
- outgoing signals are chemical/endocrine or neural
- effectors are muscles and glands
what are chell or peripheral receptors and deep body receptors
Shell or peripheral receptors: Numerous epidermal receptors, usually nerve endings which send signals to the CNS
Deep body receptors: Most importantly are cells located in hypothalamus; thse respoind to changes in core body temp by stimulating the hypothalamus to instigate appropriate and widespread responses.
Notes - body temp
Body temperature - balance between heat production and heat loss
At rest, the liver, heart, brain and endocrine organs account for most heat production
During vigorous exercise, heat production from skeletal muscles can increase 30-40 times
Heat loss mechanisms
Vasodilation of cutaneous arterioles > increased heat loss
enhanced sweating > evaporative cooling
> Decreased muscle tone, reduces heat load
heat promoting mechanisms
Vasoconstriction of cutaneous blood vessels > decreased heat loss
Increased metabolic rate due to increased secretion of thyroxine and adrenaline
shivering and increased muscle tone: skeletal muscles generate heat, with piloerection (evolutionary hangover)
Behavioural changes: warm clothing, turn on heater, look for a cuddle.
Core vs Shell (peripheral temperature
Core:
- Organs within skull, thoracic cavity and abdominal cavity
- Constant
Shell:
- The skin
- Variable
BAT (Brown adipose tissue)
Produces more heat, uses more energy, turned on when cold
increases metabolism
Beige (white fat that is activated at lower temp
