Neurophysiology Flashcards
What is neurophysiology?
studying the functioning of the nervous system
In which area of the brain does thermoregulation happen?
Hypothalamus (Preoptic area POA)
WHat are endotherms?
regulate body temp with internal mechanisms (warm-blooded)
What are ectotherms?
no internal mechanisms, regulate body temp with external means (cold-blooded)
How does thermoregulation work?
through negative feedback mechanisms: a stimulus causes a system to react by causing the opposite output
What are cold and heat defense? What is the goal of this?
systems activated when the hypothalamus feels a drop/increase in temp via thermoreceptors
• Cold defense: decrease heat loss (constriction of blood vessels, shivering)
• Heat defense: increase heat loss (vasodilation, sweating)
Name the 2 pathways of thermal infromation to the brain, their destination and their function
• Spinothalamocortical pathway (STC): destination is the somatosensory cortex via the thalamus
○ Info leading to perception of temperature
• Lateral parabrachial nucleus (LPB): destination is POA (also called LPB-POA pathway)
○ Info leading to thermoregulation
Is the Spinothalamocortical pathway (STC) necessary to produce temperature-regulation behaviours?
No
WHat is energy homeostasis?
Process that maintains cellular metabolism (depends on a supply of calories and oxygen)
Energy demands of the body are met by: (3)
• The release of glycogen by the liver (transformed back into glucose)
• Release of triglycerides from fat cells, which are transformed into fatty acids and ketones
OR by food (macronutrients such as carbs, proteins and fats)
What is the prandial state?
immediately after eating, when your energy stores are replenished (being “fed”) and nutrients flow into the bloodstream
What is the postabsorptive state?
nutrients no longer enter the bloodstream, and body relies on energy stores in the liver as glucose and from fat cells (a while after eating)
What are hormones?
chemical messengers that can have effects on cells distant from the cells that released them
What is hunger?
drive generated when energy stores are not sufficient to sustain energy balance
What is satiety?
state of being fed to the feeling of satisfaction that follows a meal
Define ghrelin and its main role in the body
Ghrelin: hormone found mainly in the stomach
• It’s orexigenic: it promotes eating
• High levels 20-30 mins before a meal, when there is no food in stomach
Define leptin and its main role in the body
Leptin: hormone produced/released from stomach, and suppresses hunger (anorexigenic)
• Secreted in response to high levels of insulin and glucose (will be more secreted after a large meal for a few days)
What is insuline? (role, effect)
- Also anorexigenic
- Relesaed by cells of pancreas
- Related to glucose levels
- Inhibits AgRP and NPY in the arcuate nucleus and has excitatory effect on POMC and CART neurons
What is cholecytokinin (CKK)? (role, effect)
- Released from small intestine when stomach is full
- Binds on receptors of vagus nerve and carries inhibitory messages to hypothalamus
- Suppresses appetite
What is peptide tyrosine tyrosine (PYY)? (role, effect)
- Released from large intestine after meals
- Suppresses appetite by inhibiting ArGP and NPY
- Has no effect on POMC and CART neurons