Unit 1 Flashcards
what causes a fever
increase in thermoregulatory set point
what increases the regulatory set point of the body
prostaglandin
response to cold
decrease blood flow to the skin
response to heat
increase blood flow to skin
what is there an increase in during sweating
ACh, Bradykinin
is the symp NS increased or decreased when responding to heat
decreased (Ep)
what hormone/NT is increased when responding to cold
NE
properties of carrier mediated transport
- saturation - transport maximum (only so many carriers)
- chemical specificity - the binding site for specific solutes
- competition
depolarizaton (more or less -)
less -
hyperpolarization (more or less -)
more -
why is membrane potential negative?
- the Na+, K+ pump (3 Na out, 2 K in)
- the membrane is more permeable to K+ than Na+
- A- (organic anions) are impermeable and are therefore trapped inside along the membrane
what is membrane potential usualy?
-70 mV
ENa+
+61 mV
EK+
-90 mV
ECl-
-61 mV
absolute refractory period
when voltage-gated Na+ channels are already opening or inactivated
* cannot get another AP
Relative refractory period
occurs when the me,brane is in the after-hyperpolarization phage
* AP can occur, more difficult because Vm is further away from threshold
myelinated axons
AP jumps from node to node, only form AP at each node
non-myelinated axons
AP can’t go backward
EPSP (exitatory postsynaptic potential)
increase probability of AP
* NT bind to a receptor that causes depolarization
* open Na+ or Ca++ channel
* close K+ channel
can EPSP reach threshold?
only if there is summation, alone one EPSP cannot reach threshold
IPSP (inhibitory postsynaptic potential)
decreases the probability of an AP
* NT bind to a receptor and causes hyperpolarization
* close Na+ or Ca++ channel
* open K+ channel
what happens if a Cl- channel opens?
Vm goes twoard -61 mV
* always inhibitory because it acts to clamp Vm at a potential hyperpolarized from threshold potential
spatial summation
APs are arriving at many synapses on one neuron with postsynaptic potentials summating
temporal summation
APs coming down one axon rapid enough for postsynaptic potentials to summate at that synapse
anterograde
from soma
retrograde
toward soma
substance P
pain transmission
what blocks substance P release
opioids
glutamate
main excitatory NT in the brain and spinal cord
AMPA receptor
open Na+ channels
NMDA receptor
open Ca++ channels
what does Ca++ do
changes spine shape (makes synapses stronger)
only happens when strong activation of synapse -AMPA receptor
what happens if there is too much Ca++ influx
neuronal death
GABA
main inhibitory NT in the brain
GABAa
open Cl- channel (post synaptic)
GABAb
open K+ channel (presynaptic)
glycine
main inhibitory NT in spinal cord
NE acts on
alpha and beta receptors
nictotinic receptors (nACh)
ionotropic (alter ion channels)
muscarinic receptors (mACh)
metabotropic (alter 2nd messangers)
cessation of transmitter action
- enzymatic destruction
- reuptake
- diffusion
- receptor desensitation
transduction
sensory information is converted into an electrical signal
receptor/generator potentials
graded potential that is generated at the sensory receptor
*it must cause an AP to sense the stimulus
adaptation
decrease in generator during a consant stimulus
accomodation
increase in threshold needed to produce an AP
* caused by inactivation of voltage gated Na+ channels
* shifts threshold to a more depolarized point (harder to reach threshold)
lateral inhibition
inhibition of information from neighboring receptors - the strong signal
does the parasymp division of ANS have a long or short preganglionic axon
long
does the symp division of the ANS have a long or short preganglionic axon
short
which division acts through the adrenal medualla
symp division
function of basal ganglia
involuntary adjustment to voluntary movement
function of cerebellum
receives input form cortez + sensory
* compares postural reflexes
* learned movement (stored)
function of cerebral motor cortex
voluntary control
synapse
- neuron to neuron
- many different NTs possible
- summation required to initiate an action potential
- may be excitatory (EPSP) or inhibitory (IPSP)
neuromuscular junction
- neuron to skeletal muscle fiber
- NT is always ACh
- no summation - AP in axon causes an EPP which causes an AP in the skeletal muscle fiber
- always excitatory - EPP is always a depolarization
role of gamma-mn
when gamma-mn is firing when the muscle is shortened, the stretch receptor continues firing
