homeostasis Flashcards
what is negative feedback?
its a one-step change like the thermostat
Aka dynamic equilibrium,
How is negative feedback started?
This occurs by a receptor which is something that has the ability to make changes in the body
Then to an integrating/control centre that processes and “makes a decision”
Effector which is the cell/organ that makes the corrective action to restore homeostasis.
what is positive feedback
its leaning into the problem more to create a larger change (its a loop)
Biggest one is either a heart attack or giving birth
what kind of transmission is the nervous system?
sends electrical and chemical messages
It can be excitable and respond to stimulus
Conductive producing electrical signals that are quickly conducted to other cells.
Secretion of neurotransmitters.
what are astrocytes?
Abundant glial cells
Connect to blood capillaries
Convert glucose to lactate
Secrete nerve growth
Communicate electrically
Absorb excess neurotransmitters and ions.
what is the electrical potential?
Charged particles between two points
What is an EPSP
this is an excitatory post synaptic potential. (Na, and K)
what is an ipsp
this is an inhibitory post synaptic potential. (Cl, and K)
what is the CNS
the central nervous system includes the brain and spinal cord
what is the PNS
the peripheral nervous system which controls all other nerves except the brain and spinal cord.
what is a leak channel?
constant permeability allowing free flowing of ions
what is a voltage gated channel?
channels activated by changes in the charge on either side of the membrane.
what is a ligand gated channel?
these open in response to an enzyme bonding to a spot on the channel causing it to open.
what is a mechanically gated channel?
opens in response to pressure on the membrane.
what is the role of ATPase pump?
this maintains the gradient on either side of the membrane keeping high concentration of sodium out and high conc of K inside.
what is temporal summation?
this is when EPSPs cause an action potential to be pushed through the neuron.
what is spatial summation?
this is where there is multiple depolarizations at the same time but in different spaces.
what are oligodendrocytes
form myelin sheath
what are ependymal cells
line internal cavities and secrete and circulate cerebral spinal fluid
what are microglia
wander through CNS looking for damage and debris.
what are the properties of local potentials
graded (vary with stimulus strength)
reversible
decremental (weaken as spread from point of stimulation)
excitatory or inhibitory
action potential properties?
all or none (if threshold reached the neuron fires at maximum voltage)
non-graded
non-decremental
irreversible
