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Flashcards in neurons Deck (54)
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1
Q

nerves

A

Cells called neurons bundled together in a sheath of connective tissue

2
Q

neurons

A

fits form to function

cells that transmit impulses

3
Q

neuron structure

A

Dendrites : fine branches that receive signals
Cell body : nucleus & organelles
Axon : transmits signal
Synaptic terminal : passes signal to next cell

4
Q

Synapse / synaptic cleft

A

Interstitial space between synaptic terminal and next cell

5
Q

Signaling neuron

A

is the presynaptic cell

6
Q

receiving cell is the

A

Postsynaptic cell

7
Q

neurotransmitters

A
signaling molecules (chemical messengers)
Carry signal from synaptic terminal to receptors on postsynaptic cell
8
Q

Glia

A

cells that support neurons
nourish
regulate surrounding interstitial fluid

9
Q

schwann cells

A

make myelin in PNS
(peripheral nervous system)
glia cells

10
Q

information processing three stages

A

sensory input
integration
motor output

11
Q

external Sensory neurons

A

detect things from outside a. mechanoreceptors (tough and pressure)

b. chemoreceptors (chemicals, smell, taste)
c. photoreceptors (light, picture)

12
Q

internal sensory neurons

A

detect things from Inside

a. baroreceptors (blood pressure)
b. pain receptors

13
Q

CNS

A

central nervous system…spinal cord and brain

somatic- controls voluntary movement of skeletal muscle

14
Q

PNS

A

PNS = peripheral nervous system.. All other nerves

AUTONOMIC- CONTROLS SELF REGULATED ORGANS AND GLANDS

15
Q

integrators

A

Found in CNS : central nervous system
called interneurons-connect neurons in brain & longitudinal nerve cord (spinal cord)
process info sent in by
sensory neurons

16
Q

motor neurons

A

transmit signal from CNS to effector cells
muscle cells
endocrine cells

17
Q

simple diffusion

A

very small, not charged

ex water

18
Q

facilitated diffusion

A

protein channel

19
Q

active transport

A

against conc. Grad

protein pump or co-transporter (pump two things one in one out)

20
Q

Resting potential

A
Sodium potassium pump (co transporter)
active transport. 3Na put, 2K into cell
creates concentrated gradient 
K channels leak ions back out 
more positive out than in cell 
-70 mV potential energy…voltage in cell
21
Q

how much potassium and sodium go in and out of the cell

A

2 K+ in for every 3 Na+ out

more K+ leaks out than Na+ leaks in

22
Q

Equilibrium Potential

A

magnitude of voltage across membrane

23
Q

Hyper polarization

A

resetting cell
inside even
more negative…increase K diffusing out

24
Q

Depolarization

A

sends signal

inside becomes less negative…open Na channels

25
Q

graded potentials

A

different levels of depolarization

a. different neuron responses
b. no response or action potential
c. depolarization signals are summative

26
Q

low grade potential

A

Low grade: small stimulus, depolarization does not reach trigger zone with high enough energy = no action potential sent down axon

27
Q

high grade potential

A

High grade: intense or long lasting
Signal reaches trigger zone at or above threshold level
Action potential send down axon

28
Q

Action Potential: massive depolarization process

A

A. Sum of depolarization (from dendrites)signals causes depolarization level to reach threshold
B. voltage-gated Na channels open (floods Na)
C. positive feed back opens more
D. Na flow brings voltage closer to 0mV then above 0mV to be positive
E. voltage gated K channels open (because overshoot)
F. restore negative cytoplasm
G. undershoot = too much negative charge inside (close all gates, restraining period)
H. resting potential
restored by NaK pumps (resets back to -70)

29
Q

Action potential:quick reversal of polarity

A

A. Action potential is all or nothing
B. Na+ flow in as fast as possible for .5ms
C. Then Na+ gates shut and K+ gates open

30
Q

passing action potential on

A

. One patch of membrane activates the Na+ gates next to it by becoming positive inside…..causes more Na+ gates to open
Propagation is 1 way due to gate inactivation. refractory period

31
Q

refractory period =

A

Na gated channels are inactivated

32
Q

Saltatory conduction (leap)

A

Nerve impulse
jumps between
Nodes=faster
transmission

33
Q

myelin

A

insulator

34
Q

nodes of ranvier

A

space between schwann cells

35
Q

Electrical synapse

A

direct transmission
of electric charge via gap junctions
=rapid unvarying response (brain)
cant be modified or stopped

36
Q

Chemical Synapse

A

Depolarization opens Ca+ channels
Ca+ causes synaptic vesicles to release neurotransmitters by exocytosis
Neurotransmitters diffuse to postsynaptic cell & bind to receptors

37
Q

two types of neurotransmitters

A

excitatory and inhibitory

38
Q

excitatory neurotransmitters

A

causes depolarization (encourages signal transmission)

39
Q

inhibitory neurotransmitters

A

causes hyperpolarization (discourages signal transmission)

40
Q

Ach neurotransmitter

A

acetylcholine (muscle) both excitatory and inhibitory

41
Q

serotonin

A

mood/ memory/sleep

42
Q

epinephrine/norepinephrine

A

(called adrenalin & noradrenalin in endocrine function)

43
Q

transduction

A

passing action potential to next cell

44
Q

ligand

A

any molecule that binds to a receptor

45
Q

receptors

A

Most = ligand-gated ion channels

a. neurotransmitter = the ligand
b. binding of ligand opens the gate

46
Q

excitatory receptors

A

some let K+ & Na+ pass to depolarize

excitatory

47
Q

inhibitory receptors

A

some let in Cl- to hyperpolarize (inhibitory)

48
Q

receptors activating second messenger

A

slower longer lastingresponse

b) binding n.t. activates G protein
c) G protein activates enzyme to make ATP into cAMP
d) cAMPs activate protein kinase As
e) Kinase As phosphorolate many channels = open them
f) many kinase As = amplified signal

49
Q

EPSP

A

excitatory postsynaptic potential encourages ps cell response

50
Q

IPSP

A

inhibitory pulls the cell back from threshold (restores resting polarization)

51
Q

Integration

A

summation of EPSP & IPSP determines response of cell

52
Q

Spatial summation

A

multiple synapses of same cell receive signal

53
Q

Temporal summation

A

rapidly repeated signal

54
Q

Clearing synaptic clefts: Neurotransmitters cleared by…

A
  1. diffusion
  2. re-uptake into pre-synaptic cell
  3. enzyme mediated breakdown