Module 4 - Nervous System Flashcards
1
Q
central nervous system
A
- brain & spinal cord
- processing and control center of nervous system
2
Q
brain
A
- found in cranial cavity
- four parts: brainstem, cerebellum, cerebrum, diencephalon
3
Q
spinal cord
A
- continuous with medulla oblongata and descends into vertebral canal
- consists of 31 segments with 31 pairs of spinal nerves
4
Q
peripheral nervous system
A
- cranial & spinal nerves, special sense organs
- somatic, autonomic, and enteric nervous systems
5
Q
somatic nervous system
A
- voluntary nervous system
- somatic afferent (sensory) nerve fibers transmit sensory info from body surface receptors to CNS
- somatic efferent (motor) nerve fibers relay impulses from CNS to skeletal muscles
6
Q
autonomic nervous system
A
- involuntary nervous system
- autonomic afferent (sensory) nerve fibers transmit sensory info from receptors in visceral organs to CNS
- autonomic efferent (motor) nerve fibers relay impulses from CNS to smooth muscle, cardiac muscle, and glands
7
Q
enteric nervous system
A
- nerves extending throughout GI tract
- enteric afferent (sensory) nerves transmit info such as chemical change from GI tract to CNS
- enteric efferent (motor) nerve fibers relay impulses to smooth muscle and GI tract glands
8
Q
peristalsis
A
waves of smooth muscle contraction, propelling food through GI tract
9
Q
sympathetic division
A
stimulatory role
10
Q
parasympathetic division
A
inhibitory role
11
Q
enteric nervous system
A
- involuntary
- enteric plexus of nerves extending throughout GI tract
- enteric afferent (sensory) nerve fibers transmit sensory info from GI to CNS
- enteric efferent (motor) nerve fibers relay impulses to smooth muscle and glands of GI tract; responsible for glandular secretions
12
Q
peristalsis
A
waves of smooth muscle contraction, propelling food through GI tract
13
Q
neurons
A
basic components of nervous system
14
Q
sensory neurons
A
transmit stimuli from body to CNS
15
Q
interneurons
A
remain within CNS, process and store information
16
Q
motor neurons
A
transmit stimuli from CNS to the body
17
Q
unipolar neuron
A
only has one nerve process extending from the cell body (found in ganglia)
18
Q
bipolar neuron
A
has two nerve processes extending from the cell body (found in retina, inner ear)
19
Q
multipolar neuron
A
has multiple nerve processes and dendrites extending from a singular cell body (majority of CNS)
20
Q
what are the CNS neuroglia?
A
astrocytes, oligodendrocytes, microglial cells, & ependymal cells
21
Q
astrocytes
A
- largest & most abundant
- connections with capillaries, neurons, synaptic endings, pia matter
- function: anchor to neuron, blood-brain barrier, recycle excess ions, secrete chemicals for neuron growth & migration, repair damaged tissue
22
Q
protoplasmic astrocytes
A
short, branching cytoplasmic processes in grey matter
23
Q
fibrous astrocytes
A
longer, unbranched cytoplasmic processes in white matter
24
Q
oligodendrocyte
A
- smaller with fewer cytoplasmic processes
- wrap tightly around axons, covering with layers of myelin sheath for insulation
- form segments of sheath around several axons at once, thought to contribute to axonal regrowth
25
microglial cells
- smallest of CNS neuroglia
- thorn-like processes extending from ovoid bodies
- remove cellular debris, invading microorganisms, and nervous tissue damaged by phagocytosis
26
ependymal cells
- single rows of cuboidal to columnar epithelial cells
- line ventricles of brain and central canal of spinal cord
- secrete and monitor cerebrospinal fluid
- form semipermeable membrane between CSF and interstitial fluid of CNS
- microvilli & cilia help circulate CSF
27
what are the PNS neuroglia?
schwann cells & satellite cells
28
schwann cells
- similar to oligodendrocytes, form myelin sheath around axons
- play role in regeneration of PNS neurons by guiding & stimulating regrowth
- many myelinate a single axon, gaps called Nodes of Ranvier
29
satellite cells
- flat cells surrounding neuronal bodies residing within ganglia
- provide structural support & form barrier, regulating exchange of substances
30
myelin
covering of lipid and protein that surrounds axons & increases with age
31
nerves
cord-like structure composed of bundles of neuronal axons that transfer sensory information to the CNS and motor information from CNS
32
anatomy of a nerve
axon --> myelin sheath --> endoneurium --> bundles of nerve fibers --> perineurium --> epineurium
33
membrane potential
build up of negatively charged ions in membrane, and positively charged outside membrane
34
ion channels
allow for flow down electrochemical gradient, creating a current
35
voltage gated ion channel
- open in response to changes in membrane potential
- activation gate closed at rest
36
ligand gated ion channel
open in response to binding of neurotransmitter/hormone latching to receptor
37
mechanically gated ion channel
open in response to mechanical forces: stretching, vibration, pressure, etc.
38
sodium / potassium pump
- Na+ higher outside, K+ higher inside
- pumps 3 Na+ out and 2 K+ in
39
leakage channel
- open and close randomly
- more K+ than Na+ channels
40
depolarizaton
- plasma membrane becomes less negatively charged
- reaching threshold of -55mv causes voltage gated channels to open
- sodium rushing in, pushing membrane potential to the positives, action potential then passing through
41
repolarization
voltage gated potassium channels open, Na+ flows out
42
hyperpolarization
- no possibility of another stimulus, inactivated Na+ channels
- sodium channels open but only strong stimulus can trigger action potential
- K+ still open, making depolarization harder
43
saltatory conduction
- occurs in myelinated axons
- myelin sheaths lack voltage gated channels, action potential jumps from node to node
44
continuous conduction
- occurs in unmyelinated axons
- sodium influx creates local positive charge, depolarizing region of cell
- depolarization of one region triggers depolarization of adjacent region
45
why does the action potential only propagates towards terminal?
despite current flowing in both directions, voltage gated channels become inactive, pushing current in other direction
46
what is the speed of propagation determined by?
myelination, axon diameter, temperature
47
mechanoreceptor
sense mechanical force like touch, vibration, pressure, and stretch
48
thermoreceptor
sense change in temperature
49
photoreceptor
sense light
50
chemoreceptor
chemicals
51
nociceptor
sensory receptor of painful stimuli
52
osmoreceptor
sense osmotic pressure
53
what are the three parts of the brainstem?
medulla oblongata, pons, midbrain
54
parts of the diencephalon?
thalamus, hypothalamus, epithalamus
55
thalamus
mood, emotions, movement, visual & auditory info
56
hypothalamus
sleep/wake cycle, thirst, endocrine system
57
epithalamus
emotional response to olfaction (smell)
58
frontal lobe
cognitive thought and memory
59
temporal lobe
auditory area, Wernicke's area (speech comprehension), learning and memory, emotions
60
parietal lobe
body orientation, primary and gustatory cortex (taste)
61
occipital lobe
visual cortex & interpretation
62
gyri
folds and bumps of brain
63
sulci
grooves and indentations of brain
64
meninges
layers between brain and skull: pia mater, arachnoid mater, dura mater
65
subarachnoid space
space between pia mater and arachnoid mater, CSF fluid circulated here
66
sinuses
peristeal and meningeal layers separate to create dural sinuses
67
why is the blood brain barrier important?
breakdown of the barrier by toxins, inflammation, or trauma is life threatening
68
