Nervous System Flashcards
1
Q
nervous system consist of…
A
- central nervous system CNS
- peripheral nervous system PNS
2
Q
what causes impulses?
A
nervous system stimulation causes electrical signals
3
Q
stimulus
A
causes change in internal + external environment
4
Q
receptors
A
converts energy from stimulus into electrical impulses (functional cell of nervous system)
5
Q
PNS portion of body
A
nerves
6
Q
CNS portion of body
A
brain + spinal cord
7
Q
effectors consist of…
A
muscles + glands
8
Q
cells of nervous system
A
- glial cells
- neurons
9
Q
glial cells (neuroglia) characteristics
A
- function to support neurons
- capable of mitosis
- more of these (85% of brain cells)
- 6 types: 4 in CNS & 2 in PNS
10
Q
types of glial cells in CNS
A
- astrocytes
- microglia
- ependymal cells
- oligodendrocytes
11
Q
astrocytes
A
form portion of the blood brain barrier
- surround blood capillaries
12
Q
microglia
A
function in protection against infection - becomes phagocyte
13
Q
ependymal cells
A
lines cavities in CNS, ventricles + spinal canal
- secrete + circulate cerebrospinal fluid
14
Q
oligodendrocytes
A
function to produce myelin
15
Q
what is myelin?
A
fatty insulating substance that surrounds the axons of neurons
16
Q
types of glial cells in PNS
A
- schwann cells
2. satellite cells
17
Q
schwann cells
A
produce myelin sheath of neuronal axons located in PNS
18
Q
satellite cells
A
found around neuronal cell bodied in ganglia
19
Q
neuron characteristics
A
- function to integrate + store info
- conduct electrical impulses
- ~15% of brain cells
- cannot reproduce
20
Q
neuronal structure consist of…
A
- cell body
- dendrites
- axons
21
Q
cell body characteristics
A
- contain typical cellular organelles w/ exception of centrioles
- rough ER is called Nissl bodies
22
Q
why are centrioles not in the cell body of neurons?
A
centrioles cannot complete mitosis
23
Q
dendrites characteristics
A
- short, branching projections from cell body
- receive incoming messages + send to cell body
24
Q
axons characteristics
A
- extends from cell body
- myelinated / unmyelinated
- generates + transmits nerve impulses
25
what joins the cell body + axon?
axon hillock
26
what's at the end of the axons?
axon terminal that contains synaptic end bodies
27
what is a myelinated axon sheath?
wrap around axon that has many layers of cell membrane
28
what produces myelin?
schwann cells in PNS and oligodendrocytes in CNS
| - lipoprotein
29
nodes of ranvier
gaps in myelin along axon
30
where are the myelinated neurons?
CNS: tracts
PNS: nerves
31
neurons can be classified based on...
structural / functional classification
32
structural classification is + has...
- according to number of processes extending from cell body
| multipolar, bipolar, unipolar
33
multipolar
many processes ext. from cell body
- 1 axon many dendrites
- interneurons + motor neurons
34
bipolar
2 processes ext. from cell body
- 1 axon 1 dendrite
- sensory neurons (sight+olfaction)
35
unipolar
one process ext. from cell body
- divides into peripheral + central processes
- always sensory neurons
36
functional classification is + has...
- according to direction of impulse propagation
| afferent/sensory, efferent/motor, interneurons
37
afferent/sensory neurons
- collected by sensory receptors toward CNS
| - unipolar
38
efferent/ motor neurons
- move from CNS to effector cells
| - multipolar neurons
39
interneurons
- b/w sensory + motor neurons-
- transmit in CNS
- 99% of neurons
- most are multipolar
40
synapse types
1. neuronal synapses
2. neuromuscular junction
3. neuroglandular junction
41
neuronal synapses
- occurs b/w 2 neurons
| - can be chemical / electric
42
neuromuscular junction
- b/w motor neuron + sarcolemma of skeletal muscle
43
neuroglandular junction
- b/w motor neuron + gland
44
chemical synapses consist of...
pre-synaptic + post-synaptic
45
pre- synaptic neuron
- brings in the signal
- axon terminal w/ synaptic end bulbs
- bulbs have neurotransmitters
46
what are neurotransmitters?
chemical messengers released upon stimulus
47
post-synaptic neuron
- dendrites receives signal
| - membrane of dendrites have specific receptors for neurotransmitter
48
nervous tissues composed of...
gray matter + white matter
49
gray matter
- from aggregation of neuronal cell bodies + dendrites
| - has nuclei + ganglia
50
what are nuclei?
clusters of neuronal cell bodies in CNS
51
what are ganglia?
clusters of neuronal cell bodied in PNS
52
white matter
- composed of myelinated axons
| - has tracts + nerves
53
what are tracts?
bundles of myelinated axons in CNS
54
what are nerves?
bundles of myelinated axons in PNS
55
what protects the CNS?
1. bone
2. meninges
3. cerebrospinal fluid?
56
meninges are...
CT membranes that surround the brain + spinal cord
57
meninges consist of...
dura mater
arachnoid mater
pia mater
58
dura mater around the brain
- 2 layers (fused)
- some areas are filled w/ venous fluid
- areas are separated by dural sinuses
59
dura mater around spinal cord
- single layer
- epidural space separates dura mater + vertebral canal (filled w/ CT, fat + vasculature)
- subdural space separates dura mater + arachnoid mater (filled with interstitial fluid)
60
arachnoid mater
- beneath subdural space
- avascular
- brain has arachnoid villi into dural sinuses (deliver CSF into blood)
- subarachnoid space is filled with cerebrospinal fluid (CSF)
61
pia mater
vascular layer located on top of the brain + spinal cord
62
what causes meningitis?
inflammation of meninges
63
cerebrospinal fluid characteristics
- located around CNS
- produced by blood vessels of ventricles (choroid plexuses)
- function: insulate brain + allows brain to float in cavity
64
ventricles of the brain
- 2 lateral in cerebrum
- 1 in diencephalon
- 1 in hindbrain
- central canal of spinal cord included
65
circulation of CSF
CSF (interventricular foramen) > 3rd ventricle (cerebral aqueduct) > 4th ventricle > subarachnoid space (arachnoid villi) > dural sinus > cerebral sinus > heart
66
hydrocephalus
- results from accumulation of fluid in ventricles
- occurs b/c cerebral aqueduct becomes blocked
- causes damage to brain tissue
67
blood brain barrier
- from by capillaries w/ tight junctions b/w endothelial cells
- astrocytes are closely associated w/ endothelial cells
- allows for certain materials (fat soluble substances) to pass thru
68
circle of willis
- cerebral arteries at base of forebrain
| - blood pressure is constant
69
what causes a constant flow of blood to the brain and why? what prevents the flow from stopping?
circle of willis
- so oxygen + nutrients can be adequately delivered
- if there were a blockage, circle shape creates an alternate path
70
artery flow in circle of wilis
2 vertebral arteries > basilar artery > posterior cerebral arteries
71
function of posterior cerebral arteries
carry blood from occipital lobe to temporal lobe
72
internal carotid arteries in circle of willis
two arteries deliver blood to either
1. middle cerebral artery
2. anterior cerebral arteries (joined by anterior communicating artery)
3. posterior communicating arteries
