Brains Divisions Flashcards
1
Q
two divisions of the nervous system
A
- central nervous system (brain and spinal cord)
2. periperhsal nervous system (nerves)
2
Q
change of brain ontogentically
A
at birth= 4/5 pounds
adulthood= 3 pounds + 100 billion neurons
3
Q
further divisions of peripheral nervous system
A
somatic nervous system (SNS)
autonomic nervous system (ANS)
4
Q
further divisons of SNS
A
afference nerves
efferent nerves
5
Q
further divisions of ANS
A
sympathethic nerves
parasympathethic nerves
6
Q
how many cranial nerves (leading to brain)
A
12
7
Q
what does the SNS do
A
interacts with external environment (skin, motor system)
8
Q
what does the ANS do
A
regulates internal environment (sensory signals, hormones, etc)
the afferent/efferent nerves carry signals to internal organs
9
Q
what are affterent nerves
A
carry sensory signals
10
Q
what do efferent nerves do
A
carry motor signals from CNS to sekeltal muscles
11
Q
what are sympathethic nerves
A
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
Q
what are parasympathethic nerves
A
CALMING (rest/digest)
project from brain/sacral
project from CNS synapse NEAR the target organ on the second stage nerves
13
Q
differences between parasympathethic and sympathethic nerves
A
parasympethic= conserve energy/calming + project near target organ
sympathethic= far from target organs + arousing/threatining situations
14
Q
what is the brain protected by
A
bone
3 meninges
cerebrospinal fluid
3 protective membranes
15
Q
what does cerebrospinal fuid do
A
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
Q
what is the blood brain barrier
A
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
Q
what are the principles of the sympatethic/parasympethihic nerves
A
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
Q
what are cranial nerves
A
12 nerves projecting from brain that are purely sensory and used for diagnosis basis:
i.e. olfatory, optic, etc.
19
Q
composition of the brain
A
60% fat needs 20% of al loxygen 2% of all bodyweight 86billoin neruons weights 3lb at adulthood
20
Q
what are meninges
A
3 protective membrances encasing the CNS
21
Q
what do meningnes consists of
A
- dura matter
- arachonid membrane + sub-arachanoid space
- pia matter
22
Q
what is dura mater
A
thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord
23
Q
what is the arachonoid membrane
A
spiderlike web menginge layer
consits of sub-arachoid space where blood vessels/cerebospinal fluid is found
24
Q
what is pia mater
A
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
31
axon hillock
cone shaped region at the junction between the axon and cell body
32
dendrites
short procesesses from soma that revieve electircl signals from other neurons
33
soma
cell body of the neuron= metabolic center
34
axon terminals/buttons
release chemicals into synaps
35
synapse
gaps between neurons through which chemical signals are transmitted
36
schwann cells
a glial cell in PNS= myenliate the PNS nerves and can create axonal regrowth post-damage
37
endoplasimic reticulum
folded membranes in the cell for fat/protein synthesis
38
synaptic vesicles
membrane pacakges storing neurostransmitter molecules to release them into synapses
39
neurotransmitters
molecules relesaed from active neurons infleucning the activity of other cells
40
what is the neuron cell membrane compsoed of
a lipid bilayer with protein molecules for functional properites of the cell
41
types of neurosn
unipolar
bipolar
multipolar
multipolar interneruon
42
unipolar neurons
1 axon
43
bipolar neurons
2 axons
44
multipolar neurons
2+ axons
45
multipolar interneruons
have no axons/super short axons
integrate the neural activit within a single brain structure as opposed to conducting signals from one strucutre to anoher
46
what are neurons specialized for
1. recpetion
2. conduction
3. transmission
47
distribution of neurons
- compsoed of cell bodies/axons
- IN CNS; found in clusters
- in PNS; found in ganglion/ganglia
48
what are bundles of axons called?
in cns= tracts
| in pns= nerves
49
what do glial cells do (4)
1. control blood brain barrier
2. support neurons (nutrition, waste, etc)
3. exchange chmicals with neurons and maintain synapses
4. modulate neural activity
50
types of glial cells (4)
1. oligodendrocytes
2. schwann cells
3. microglia
4. astrocytes
51
what are oligodendrocytes
extensions that wrap aroudn axons of some neurons in the CNS
they myenliate the CNS axons
increased speed/effiency of axonal conduction in several segments
52
what are microglia
respond to injury by multiplying/engulfing cellular debris + triggering inflammatory responses
53
what are schwann cells
perform simlar function in peripheral nervous system;
each constitute 1 myselin segment as opposed to many
54
what are astrocytes
cover brain besswels
allow passage of chemicasl from blood into CNS neurons
provide nutrition/clear waste
send and recieve signals form neurons/other glial cells to control, establish and maintain synapses between neurons
55
what can only schwann cells do
guide axonal regrowth after damage is
56
challenge of studyign neurons
axons/dendrites are intricately intertwined
57
what are some neuroanatomical techniques to study neurons
1. golgi stains
2. nissl stain
3. electron microscopy
58
golgi stain
ability to see individual neurons using Golgi (silver cromate staining them black)
59
nissl stain
allows for innter strucutre/number of neurons in an area using cresyl violet dye binding to singular neuran cell bodies
60
electron microscopy
provides details of neuronal structure using electron-subtances that magnify light using photographic film
61
what are some neuroanatomic tracing techniues
anterograde
| retrograde
62
anterograde
used to trace paths of axons projecting away from a cell body in a particular area
63
retrogade
axons projecting into a particular area
64
what 3 axes does the nervous system of a vertebrate have
1. anterior posterior
2. dorsal ventral
4. medial lateral
65
anterior-posterior
raustral caudal (back of head and forehad)
66
dorsal ventral
top/bottom of head (think dolphin)
67
medial lateral
towards/away form midline of body's lateral surfaces (facing towards you)
68
anterior
nose end (rostral)
69
posterior
tail end (caudal)
70
medial
midline of body
71
laeral
away from body
72
proximal
close
73
distal
far
74
what 3 planes are there of the vertebrate NS
1. saiggital plane (midline)
2. horizontal plane
3. frontal plane (vertical; center)
and a cross section!
75
2 areas of the spinal cord
gray matter
| white matter
76
what is gray matter
cell bodies and unmyelinated interneurons with 2 dorsal arms (dorsal/ventral horns)
77
what is white matter
myenliated axons
78
what does the dorsal root ganglia consist of
sensory unipolar neurons with grouped cell bodies
79
ventral root ganglia consits of
multipolar neurons grouped together
80
label the spinal cord
x
81
label the 3 axes of the brain
x
82
label the 3 planes of the brain
x
83
label a neuron cell
x
84
what are the 3 first brain divisions that develop during embryological development
1. forebrain
2. mind brain
3. hind brain
85
what are the final brain divisions you end up with as an adult
forebrain: telencephalon + diecnephalon
midbrain= mesencephalon
hindbrain= metencephalon + myencephalon
86
forebrain substructures
telencephalon + diecnephalon
87
mid brain sub structures
mesencephalon
88
hind brain sub structures
metencephalon
| myencephalon
89
order form anterior to posterior of brain divisions
```
telencephalon
diencephalon
mesencephalon
metencephalon
myelencephalon
```
90
telencephalon vs rest of structures
telencehalon= greatest growth (cerebral hemispheres)
other 4 divisions are the brain stem
91
difference between human and chimps
larger forebrain in humans as hindbrain/midbrain develop first as they are more primitive (for mechanical functions) as opposed to cognitive functions of the forebrain
92
what is the myenencephalon
the medulla! (hindbrain; posterior division)
for 1. reticular formation (network of nuclei in brian core for consciousness/alertness)
2. tracts that carry signas from brain to body
93
what is the metencephalon
hind brain
trackts/reticular formation
consits of :
1. pons
2. cerelbellum
94
what is the pons
found in metencephalon; a bulge of tracts on brain strems ventral surface that controls bladder, respiration, etc
95
what is the cerebellum
found in the metencephalon; th 'little brain' for motor coordination/cogntiive functions
its a large/convulated structure on DORSAL part of metenchealon for sensoir-motor, decision making, language, movement
96
what is the mesencephalon
aka the MIDBRAIN
| consits of the tectum and the tegmentum
97
tectum
dorsal surface of the mesencephalon (Roof)
| has collicoli pumps
inferior collicllu for auditory function and superior collicoli for visio-motor function
98
tegmentum
```
ventral to tectum
3 colourful structures:
consits of:
1. periadquductal gray + cerebral aqueduct
3. substancia nigra
4. red nucelaus
```
99
periaqueductal gray + cerebral aqueduct
part of tegmentum: gray matter which mediates analgesic/pain-reducing effects of opiate drugs
100
substancia nigra/red nucleus
part of the sensorimotor system
101
what is the diencephalon
part of the forebrain; consists of 2 structures (thalamus + hypothalamus)
102
thalamus
2 lobed stucutre joined by mass indermedia with many nuclei
contains: sensory relay nuclei, laternal geniculauate + medial + ventral posterior nuclei
the 'switchboard between subocrotical strucutures and the cortex'
103
hypothalamus
regulates unmotivated bheaviours (hormones; sleep, temperature, sex, thirst)
affects pituitary gland (hormon release, optic chiasm and mamilary body)
104
telencephalon structures
1. cerebral cortex
2. major fissures
3. major gyri
4. four lobes
5. libmic system
6. basal ganglia
7. cerelbral commisures
105
what is the telencephalon responsible for
the limbic system that mediates compex functions:
1. intiates involuntary movement
2. interprets sensory input
3. mediates complex cognitive proceseses (learning, speaking, problem solving)
106
amygdala
for emotional learning
107
hippocampus
consolidation of memory
108
how do the cerebral hemispheres communicate
via the corpus callosum
109
cerebral cortex
outer layer of grey matter of cerebrum
composed of unmyenliated neurons, fissures and sulci
deeploy conulated to increase brain volume
110
grey matter
soma + unmyenliated axons
111
white matter
myenliated axons
112
fissures
large furrow on wrinkled skin surface of cerebral cortex
are:
1. longitutidinal
2. lateral
3. central
113
sulci
small fissures
114
what are the gyri
ridges between fissures and sulci
115
types of sulci
precentral, postcentrla, suprior in respect to frontal, parietal and temporal lobes
116
what 4 lobes are there
1. frontal
2. pareital
3. temporal
4. occipital
(not functional untis but with SETS of functions)
117
occipital lobe
visual input
118
pareital lobe
tactile sentation analysis and locations of objects
directs attention
(where post-central gyrus cuts through)
119
temporal lobe
1. superior temporal gyrus= hearing and language
2. inferior temporal gyrus= comple visual patterns
3. medial position= memory
120
frontal lobe
precentral gyrus/adjacent frontal cortex= motor function
frontal cortex= complex cognitive functions (planning, evaluating outcomes)
121
what is the neocortex
6 layeres differ vy size/density in proporistion to the 2 types of cells
long axons and dendrites
columanr organization
90% of human cerebral cotex; higher cognitive function
122
what does the neocortex consists of
pyramidal cells (multipolar and large)
stellalte cells (small, interneurons)
123
limbinc system
part of forebrain; circuit of midline srcuturs circiling the thamalus involved in '4 fs' of motivation
124
4 Fs of motivation
fleeing
feeding
fighting
sexual behaviour (fucking)
125
limbic ciruirt
starts at amydalda--> posterior to it is the hippocampus which runs beneath hipocampus in medial temporal lobe
then the cignualte corte + fornix
then the septemb
126
basal ganglia motor system
plays a role in VOLONUTARY motor responses
projects form striatum (from substancia nigra)
127
what is associated with the basal anglia motor system
parkinsons disease= deterioirtaion of this pathway
128
nucleus accumens
medial porition of central striatum; plays a role in reward systems
129
major fissures 3
central fissure
laternal fissure
longitutundal fissure
130
major gyri 4
precentral gyrus
postecenral gurys
superior temporal cyrus
cingulate curus
131
limbic system 6
```
amygalda
hippocampus
fornix
cingulate cortex
septum
mammilary bodies
```
132
basal ganglia 4
amydala
caudate and putamen (striatum)
globus pallidis
133
cerebra commisures
corpus callosem
134
crebral cortex
neocortex and hippocampus
135
what does the diencephalon consits of
thamalus
hypothalamus
optic chiasm
pituitary gland
136
where is the motor cortex
between frontoal/occopital lobes
137
where is the somatosensory cortex
next to motor cortex
138
where are association ares
distributed; inteprret/inlink info form neurons
139
glial cells function
provide spiderlink suppor tto insulate and nourish cerebral hemispheres
140
label all the gyrus and fissures
x
141
types of NT
endorphins dopamine and seratonin
can be exictatory= increase AP (glutamate)
or inhibitory= prevent PA (gaba, seratonin)
142
label the functional localization of brain
x
143
plasticity of brain
brain is malleable and changes always
fire together + wire together
144
what is ynaptic prunign
less synapses than when born as we lose the synapses we dont' use for effiency
