Chapter 9 Flashcards
1
Q
what are the three basic functions of the nervous system
A
sensory function
integrative function
motor function
2
Q
what is sensory function
A
senses certain changes (stimuli) both inside and outside the body
3
Q
what is integrative function
A
analyzes the sensory information, stores some aspects, and makes decisions regarding appropriate behaviors
4
Q
what is motor function
A
respond to stimuli by initatiatin gmuscular contractions or glandular secretions
5
Q
what are the two main nervous system divisions
A
central nervous system (CNS)
peripheral nervous system (PNS)
6
Q
what is the CNS
A
brain and spinal cord
contains interneurons
7
Q
what is the pns
A
all other nerves in body
contains sensory and motor neurons
8
Q
what are the divisions of pns
A
somatic nervous system (SNS) - voluntary
autonomic nervous system (ANS) - involuntary
9
Q
what are the two types of nerve cells in the nervous system
A
neurons and neuroglia
10
Q
what are neurons
A
cells responsible for most speical functions of the nervous system: sensing, thinking, remembering, controlling muscular activity, and regulating glandular activity
11
Q
what are nueroglia
A
cells that support, nurture, and protect the neurons and maintain homeostasis of the fluid that bathes neurons
12
Q
are neurons always the same sizew
A
no they vary considerable in size and shape
13
Q
all neurons have _____ and _____ nerve fibers, which _____ to or from the cell body
A
cell body
tubular, cytoplasm-filled
conduct nerve impulses
14
Q
do neurons have organelles in the body just as normal body cells
A
yes
15
Q
what is the function of dendrites
A
receive signals from other cells
16
Q
what is the function of axon
A
transfers signals to other cells and organs
17
Q
what is the function of cell body
A
orgnaizes and keeps the cell functional
18
Q
what is the function of nucleus
A
controls the entire neuron
19
Q
what is the function of myelin
A
increases the speed of the signal
20
Q
what is the function of nodes of ranvier
A
allow diffusion of ions
21
Q
what is the function of terminal branches
A
22
Q
what is the function of synaptic knobs
A
forms junctions with other cells
23
Q
what is the function of Schwann cell
A
produces the myelin sheath
24
Q
what is the function of axonal hillock
A
generates impulse in the the neuron
25
what are the parts of a neuron
dendrites
cell body
cell membrane
axonal hillock
nodes of ranvier
schwann cell
axon terminal/synaptic knob
myelin sheath
axon
nucleus
26
what are the three types of neurons and which divisions are they in
sensory neurons PNS
interneurons CNS
motor neurons PNS
27
what are sensory neurons also called
afferent neurons
28
what are interneurons also called
association neurons
29
what are motor neurons also called
efferent neurons
30
what are sensory neurons
pick up internal and external stimuli and carry those impulses from PNS to CNS
31
what are interneurons
lie within the brain or spinal cord and link other neurons. transmit impulses from one part of the brain or spinal cord to another. they direct incoming sensory impulses to appropriate parts for processing and interpreting
32
what are motor neurons
carry nerve impulses out of the brain or spinal cord. stimulate muscles to contact or glands to release secretions
33
nueroglia fill about __ of the CNS
50%
34
what is the difference in size and number of neuroglia vs neurons
neuroglia re smaller but more numerous and neurons
35
can neurons multiply and divide
yes
36
what commonly derives from neuroglia
brain tumors (gliomas)
37
what do neuroglia do in injury
they fill the spaces formerly occupied by neurons
38
how many kinds of glial cells are there
6
39
what are two of the classifications of neuroglial cells
oligodendrocytes
neurolemmocyctes
40
what is another name for neurolemmocytes
schwann cells
41
what do oligodendrocytes do
form myelin within the CNS, brain and spinal cord
42
what do neurolemmocytes do
product myelin sheaths around PNS system
43
what is myelin
coating that goes around nerves and aids in nerve impulse conduction
44
what is the difference between white and gray matter in the brain
white - has myelin matter
gray - doesnt have myelin matter
45
action potentials/nerve impulses are all about ...
the movement of ions(charges) between the inside and outside of a neuron's membrane
46
what are important ions needed for nerve impulses
calcium (Ca 2+)
sodium (Na+)
potassium (K+)
phosphate (PO4 3-)
sulphate (SO4 2-)
47
what is potential difference
the difference in the electrical charge between two areas
48
describe when a action potential happens
inside neuron (-) outside neuron (+)
great enough potential difference must be made before an action potential can start (All or none)
the diff is created by a stimulus that the body picks up and a build-up of certain ions on either side of the nerve cell membran
49
when a neuron is undisturbed or at rest (_____) the neuron has a ___ charge inside and the membrane and outside of the neuron has a ___ charge. This is called the neurons _____ and it is called _____
no action potential happening
negative
positive
resting potential
polarized
50
why is a neuron at rest negative inside
because of sulfate ions (SO4) and phosphate ions (PO4)
These ions carry a larger negative charge
51
why is the membrane and outside of neuron positive
all the sodium ions (Na+) are outside the neuron
52
what can be found on both inside and outside of neuron
potassium ions (K+)
53
what tia resting potential
the difference in electrical charge between the inside and outside of an undisturbed or restin neuron membrane
54
in order for an action potential to be achieved, the membrane of a nerve cell must reach what is called the _____
threshold potential
55
what is threshold potential
the positive charge on teh ourside must build up large enough to start an action potential
56
what is action potential
the rapid depolarization and repolarization in one area of a neurons axon
57
what is polar
areas with unequal charges
(inside - outside +)
58
what is depolarization
change in the charge bw the membrane of the cell and the inside of the cell away from resting charge
(Action potential will be taking place at this time)
59
what is repolarization
the return of the charge bw cell membrane and the inside of cell to its resting charge
(action potential finished)
60
a nerve impulse is a ___ or a ___ as it travels throughout the neuron
chain reaction
wave of action potentials
61
nerve impulse:
the depolarization and repolarization along an entire axon
62
what are the two factors that affect the speed of nerve impulse conduction
if nerve fibers are amyelinated
of diameter of the nerve fiber is larger
63
structures that neurons form synapses/junctions with:
other neurons
muscles
glands
64
are nerve impulses all or none like muscle contractions?
yes
65
in muscles, a greater intensity of stimulation produces a stronger contraction, what happens in nerve impulses
more impulses per second
66
what is synapse
the functional connection between the axon of a neuron and the dendrite of another neuron or the membrane of another cell
67
why is the synapse called the functional connection
there is no direct connection
68
_____ cross the synapse in order to _____
neurotransmitters
relay messages from a neuron to another structure
69
how does a nerve impulse conduct from neuron to neuron
impulse travels through neuron to its end (synaptic knob)
vesicles release neurotransmitter
neurotransmitter crosses synapse and bind to receptor on next cell
70
what are neurotransmitters
chemicals within vesciles of the synaptic knob of a neuron that are secreted across a synapse to relay an impulse (message) from a neuron to whatever structure the neuron is forming a junction with
71
list the neurotransmitters
acetylcholine
(monoamines):
noreoinephrine
dopamine
seratonin
histamine
(amino acids):
GABA
glutamic acid
(neuropeptides):
Substance P
endorphins, enkephalins
(gases):
nitric oxide
72
what is the function of acetylcholine
CNS
controls skeletal muscle actions
73
what is the function of norepinephrine
CNS
creates a sense of feeling good; low levels may lead to depression
74
what is the function of dopamine
CNS
creates a sense of feeling good; deficiency in some brain areas is associated with Parkinson disease
75
what is the function of seratonin
primary inhibitory; leads to sleepiness; action is flooded by LSD, enhanced by selective serotonin reuptake inhibitor drugs (SSRIs)
76
what is the function of histamine
release in hypthalamus promotes alertness
77
what is the function of GABA
generally inhibitory
78
what is the function of Glutamic acid
generally excitatory
79
what is the function of endorphins, enkephalins
generally inhibitory; reduces pain by inhibiting substance P release
80
what is the function of nitric oxide
CNS
may play a role in memory
81
what are neurotransmitters that increase nerve impulses called
excitatory
82
what are neurotransmitters that decrease nerve impulses called
inhibitory
83
steps of skeletal muscle contractions and relaxation
- NI sent from brain toward skeletal muscle by way of motor neuron
- NI reaches SK and Ca 2+ enter through voltage gated channels
- Synaptic vesicles triggered to release the neurotransmitter ach
- Ach cross synaptic cleft and binds to receptor protein on the motor end plate of muscle fiber
- muscle impulse is created
- MI enters muscle fiber through an opening to the T-tubule and the MI reaches the terminal cisternae of the sarcoplasmic reticulum
- Ca 2+ released from terminal cisternae of the sarcoplasmic reticulum
- Ca 2+ bind to troponin
- Troponin moves tropomyosin off the actin binding sites
- myosin cross bridges raise and attach to actin binding sites
- Powerstroke, this happens many times in order for a muscle fiber to fully contract. ATP attaches to myosin cross-bridge head and then releases from actin
- nerve impulse from brain stops being sent along motor neuron. AchE decomposes Ach from the receptor protein
84
What are the events leading to the conduction of a nerve impulse
- neuron membrane maintains resting potential
- threshold stimulus received by an outside stimulus
- sodium channels in area open
- sodium ions diffuse inward, depolarizing the membrane
- potassium channels in the membrane open
- potassium ions diffuse outward, repolarizing the membrane
- an action potential has occurred and will stimulate the next area to do the same
- a wave of action potentials travel the length of the axon as a nerve impulse
