Principles of Neuroscience Lecture 16 Homeostasis Flashcards
What factors affect blood pressure?
Salt intake
Water intake
How is blood pressure maintained at a near constant rate?
Changing the heart rate
Why is regulation of blood pressure important? (2)
We need to keep a constant blood flow to the brain
High blood pressure damages blood vessels
How is blood glucose level regulated?
Insulin and glucagon
What is cellular homeostasis in a neuron?
What must be maintained?
Regulation of synthesis of ion channels & GPCR etc. -> controlling the excitability.
Volume maintenance
Stretch of a cell can damage it
Too many ion channels changes the excitability of a cell
How do some organisms maintain cell volume? How does this relate to maintenance of neuron volume?
Osmoconformers change their internal concentration so they are in equilibrium with the environment. In this way there is no movement of water in or out of the cell. This is done by taking in or excreting electrolytes Making osmolytes (longer term)
This is not a option for neurons, because changing the concentration of electrolytes changes the excitability of the cell
What is osmolality?
This is the electrolyte-water balance in the body
Describe the differences in osmolality among different species. What dictates plasma osmolality in these organisms?
Sharks have high osmolality
Fresh water animals have low osmolality
Terrestrial animals are somewhere in the middle
Exercise affects … ?
Osmolality
Failure to … Causes … In osmolality when exercising
Rehydrate during exercise
Increase
Increased osmolality when exercising leads to …
Reduced mental and physical performance
Differentiate between hypertonicity and hypotonicity
Hypertonicity: too much solute / salt
Hypotonicity: too much water
What does the body do to reduce hypertonicity?
What shouldn’t be done, why?
Excrete salts
(Reduce appetite for salt)
Increased water retention
(Increased thirst)
Drinking more water doesn’t really do much good becaus it increases your volume and thus blood pressure
What does the body do to reduce hypotonicity?
Increase salt retention
Increased salt appetite
Reduced thirst
Increase urine production
Give a rough outline of neural control of osmolality
Gut -> (vagus) -> CNS -> Kidneys