NS cells & NTs

Question 1

Nervous system & endocrine system

Answer 1

both make use of extracellular messages & receptors on target cells

Question 2

NS characteristics

Answer 2

rapid, voluntary & involuntary control, NTs are close in distance, exocytosis of all NTs, hydrophilic. 2 types - excitatory (stimulate neuron to fire AP, increase signal passage) and inhibitory (decrease chance of firing, brake)

Question 3

ES characteristics

Answer 3

slow, long-lasting effects, involuntary control, hormones (cells far apart, transported in BVs & lymph vessels

Question 4

some neurons are hormones

Answer 4

when a cell releases a chemical to a cell right next to it = NT
If a neuron releases the same chemical message into the blood = hormone

Question 5

receptors signal location

Answer 5

on PM (extracellular)
in cytoplasm (intracellular)

Question 6

autocrine

Answer 6

chemicals that are exerted & received by the same cell

Question 7

paracrine (neurons)

Answer 7

chemicals receivied by cells that affect other nearby cells

Question 8

endocrine (hormones/neurohormones)

Answer 8

secretion into blood for signaling with far away cells

Question 9

exocrine (digestive enzymes, stomach acids, sweat)

Answer 9

secretion into the external environment through a duct, usually an epithelium

Question 10

functional division of the NS

Answer 10

1. Sensory Input (PNS) - sensory receptors detect changes inside & outside of body (stimuli)
2. Integration (CNS) - processing & interpretation of input (assessment)
3. Motor Output (PNS) - response caused by activation of effector organs (m.s/glands, response)

Question 11

org of NS

Answer 11

CNS - brain/spinal cord (integration & command center)
PNS - links all the body of the CNS via spinal/cranial n.s (sensory input & motor output)

Question 12

Neural signaling path

Answer 12

sensory cell -> sensory neuron -> CNS -> motor neuron -> muscle/gland
(no stimuli) CNS -> motor neuron -> muscle/gland

Question 13

PNS organization

Answer 13

Sensory (input) and motor (output)
Motor - somatic (voluntary) and autonomic (involuntary)
Autonomic - parasympathetic (rest/digest) and sympathetic (fight/flight)

Question 14

PNS organization: Acetylcholine and NE/EP

Answer 14

Acetylcholine acts on somatic and parasympathetic
NE/EP acts on sympathetics

Question 15

sensory input

Answer 15

collect & relay sensory neurons, receive information from sensory cells
receptors are commonly proteins that are ion channels or G-protein coupled receptors
sense stimuli through sensory receptors & communicate to sensory neurons through NTs

Question 16

mechanoreceptors

Answer 16

mechanical perturbation activates the channel, depolarizes the cell, NT released, feeling sensed
proprioceptors - knowing your body is there even though there is no stimulus

Question 17

chemoreceptors

Answer 17

molecules binds to protein - feel/bind

Question 18

photoreceptors

Answer 18

senses light

Question 19

thermoreceptors

Answer 19

sense temp changes

Question 20

nociceptors

Answer 20

pain, overactivated other receptors

Question 21

what happens when sensory ability is damaged?

Answer 21

mutation in voltage-gated Na+ channel - feel no pain
Leprosy - mycobacterium infection often leads to numbness of peripheral n.s so patients can’t feel

Question 22

glia characteristics

Answer 22

supporting cells
1-5 glia : 1 neuron
mitotic

Question 23

neurons characteristics

Answer 23

receive/send info
100 years
G0 phase - not replaced
high metabolic rate - require continuous supply of O2 & glucose

Question 24

astrocytes

Answer 24

must abundant
neurons generate Na+ influx & K+ efflux, causing K+ to accumulate outside the neuron so astrocytes clean it up along with NTs
regulate ECF composition
provide nutrients
help form blood brain barrier

Question 25

microglia

Answer 25

phagocytose dying or dead cell debris & remodel synapses protect neurons help form blood brain barrier

Question 26

oligodendrocytes

Answer 26

electrical insulation - speeds electrical singaling of APs wrap around axons of myelin sheaths (processes)

Question 27

ependymal cells

Answer 27

line cavities where cilia circulate CSF to cushion/nourish CSF

Question 28

schwann cells

Answer 28

surround & form myelin sheaths around axons = insulation

Question 29

satellite cells

Answer 29

surround neuron cell body maintain chemical environments

Question 30

myelination

Answer 30

schwann cells/oligodendrocytes wrap around axon multiple times Neurons have a 3-4 nm PM thickness. As electricity goes through, the signal dissipates, myelin insulates to prevent dissipation.

Question 31

myelin sheath

Answer 31

protects/insulates axons, increases AP conduction speed

Question 32

myelinated fibers

Answer 32

axons w/myelin sheath

Question 33

nodes of ranvier (neurofibral nodes)

Answer 33

gaps on axon btw myelin sheath

Question 34

soma (cell body) components

Answer 34

biosynthetic center - PM, nucleus, organelles RER (nissl bodies) are most active in soma neurofilaments - maintain cell shape so neurons can last longer though they are only 1 um in diameter

Question 35

input (dendrites)

Answer 35

increase SA of PM so another neuron can synapse close convey short distance incoming messages to soma (GP) excitatory signals - depolarization inhibitory signals - hyperpolarize No myelin sheaths because NT would not get to surface of dendrite to fire a signal.

Question 36

output (axon)

Answer 36

vary in size (up to 1m) only 1 per neuron w/ or w/out myelin axon hillock - cone shaped area where axon arises - receive excitatory info - depolarizes - fires AP down axon