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Flashcards in Brains Divisions Deck (144)
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1

two divisions of the nervous system

1. central nervous system (brain and spinal cord)

2. periperhsal nervous system (nerves)

2

change of brain ontogentically

at birth= 4/5 pounds

adulthood= 3 pounds + 100 billion neurons

3

further divisions of peripheral nervous system

somatic nervous system (SNS)

autonomic nervous system (ANS)

4

further divisons of SNS

afference nerves
efferent nerves

5

further divisions of ANS

sympathethic nerves
parasympathethic nerves

6

how many cranial nerves (leading to brain)

12

7

what does the SNS do

interacts with external environment (skin, motor system)

8

what does the ANS do

regulates internal environment (sensory signals, hormones, etc)

the afferent/efferent nerves carry signals to internal organs

9

what are affterent nerves

carry sensory signals

10

what do efferent nerves do

carry motor signals from CNS to sekeltal muscles

11

what are sympathethic nerves

AROUSING (fight/flight)

autonomic motor nerves in the lumbar and thoracic regions of the spinal cord

they project from the CNS onto 2nd-stage neurons FAR from the target organ

12

what are parasympathethic nerves

CALMING (rest/digest)
project from brain/sacral

project from CNS synapse NEAR the target organ on the second stage nerves

13

differences between parasympathethic and sympathethic nerves

parasympethic= conserve energy/calming + project near target organ

sympathethic= far from target organs + arousing/threatining situations

14

what is the brain protected by

bone
3 meninges
cerebrospinal fluid
3 protective membranes

15

what does cerebrospinal fuid do

supports/cushions the brain
fills the subarachoid space, ventricles and spinal cord
produced by the choroid plexuses in pia matter
can be blocked by tumors in channels linking ventricles

16

what is the blood brain barrier

a mechanism that impeded passages of toxic substances from blood into brain cells of blood vessels that are tight packed but some large molecules are actively transported

17

what are the principles of the sympatethic/parasympethihic nerves

2 stage neural pathways; project from CNS toowards organs and synapse with other neurons

target neurons revieve inputs from both PN and SN and are controlled by relative levels of their activiity

18

what are cranial nerves

12 nerves projecting from brain that are purely sensory and used for diagnosis basis:
i.e. olfatory, optic, etc.

19

composition of the brain

60% fat
needs 20% of al loxygen
2% of all bodyweight
86billoin neruons
weights 3lb at adulthood

20

what are meninges

3 protective membrances encasing the CNS

21

what do meningnes consists of

1. dura matter
2. arachonid membrane + sub-arachanoid space
3. pia matter

22

what is dura mater

thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord

23

what is the arachonoid membrane

spiderlike web menginge layer

consits of sub-arachoid space where blood vessels/cerebospinal fluid is found

24

what is pia mater

the delicate, inner-most part that supports CNS and produced cerebrospinal fuid

25

what are neurons

cells sepcialized for reception, conduction and transmission of electrical signals

26

types of cells in nervous system

neurons
glial cells

27

structural elements of a neuron

cell body
axon
dendrites
cell membrane
soma
axon hillock
nodes of Ranvier
myselin
buttons/axon terminals
synapses

28

nodes of ranvier

gaps between myelin where saltatory conduction occurs

29

axon

long narrow process projecting from cell body where action potentials travel down

30

myelin

fatty insulating layer to allow for saltatory conduction