4th exam-Nervous and Endocrine system Flashcards
1
Q
nervous system functions to
A
- communicate with and regulate other body systems
- maintain homeostasis
- works in conjunction with endocrine system
2
Q
rapid, brief responses (action potentials and neurotransmitters)
A
Nervous system
3
Q
slow, prolonged response (hormones)
A
Endocrine system
4
Q
functions of the nervous system
A
perception memory emotion voluntary movements behavior
5
Q
three basic components of nervous system function
A
sensory function
integrative function
motor function
6
Q
sensory function
A
- detect internal and external stimuli
- sensory information carried to spinal cord and brain via sensory neurons
7
Q
integrative function
A
- process sensory info (analysis, integration, and storage [memory])
- association neurons (inter-neurons)
8
Q
motor function
A
- respond appropriately to sensory info
- response info carried to effectors (muscles and glands) via motor neurons
9
Q
nervous system structures
A
brain cranial nerves 12 spinal cord spinal nerves 31 ganglia enteric plexuses sensory receptors
10
Q
the two divisions of the nervous system
A
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
11
Q
components of central nervous system - cns
A
brain
spinal cord
12
Q
components of peripheral nervous system - pns
A
cranial nerves (& their branches)
spinal nerves (& their branches)
ganglia
sensory receptors
13
Q
the 3 subdivisions of the Peripheral nervous system PNS
A
-somatic nervous system SNS
-Autonomic nervous system ANS
-Enteric nervous system ENS
….each has a sensory and motor component
14
Q
Somatic nervous system SNS
A
- sensory neurons from “organs, body wall, limbs, etc
- motor neurons leading to skeletal muscle (voluntary control)
- soma = body
15
Q
Autonomic nervous system ANS
A
- sensory neurons from “visceral organs”
- motor neurons leading to smooth muscle and cardiac muscle and glands (involuntary control)
- auto = self; nomic = law
16
Q
Enteric nervous system ENS
A
- enteric plexuses of gastrointestinal tract (involuntary)
- sensory neurons from GI tract
- motor neurons leading to smooth muscle and glands of GI tract
- enter = intestines
17
Q
Nervous tissue consist of
A
- neurons, that “generate action potentials”, “electrically excitable”
- neuroglia, support, nourish, and protect neurons
18
Q
neurons and excitable cells respond to stimuli by
A
generating a nerve impulse (action potential)
19
Q
an electrical signal that propagates (travels) along neuron in one direction (dentrite –> axon)
A
action potential
20
Q
typical neuron consists of these 4 parts
A
- cell body
- dendrites
- axon
- telodendria
21
Q
cell body includes
A
- nucleus
- cytoplasm
- typical organelles
22
Q
Dendrites have
A
- multiple nerve fibers (often short and branched)
- input portion of the neuron (receives signals from environment or from another cell)
23
Q
Axons include
A
- single nerve fiber
- output portion of the neuron (delivers signal to other cell)
- often long and branched only at end “telodendria”
24
Q
Telodendria
A
- end in synaptic terminals
- neurotransmitters stored in synaptic vesicles within synaptic terminals
25
consists of: one axon
| & several dendrites
multi-polar neurons
26
consists of : one axon and one main dendrite
bi-polar neuron
27
consists of: -sensory neruons,
| -axon and dendrite fuse before meeting cell body
uni-polar neruon
28
consists of: -more than 2 process
| -axons cannot be distinguished from dendrites
anaxonic neuron
29
relay sensory information from sensory recepters or sensory cells to CNS
sensory (afferent) neurons
30
relay motor information from CNS to effectors (muscles or glands)
Motor (efferent) neurons
31
- link sensory and motor neurons witin the CNS
| - integrate (process) incoming sensory information and elicit appropriate motor response
interneurons (assonciation neurons)
32
-support, nourish and protect neurons
neuroglia
33
CNS includes ____ diff types of neuroglial cells
4 types
- astrocyte
- oligodendrocytes
- microglia
- ependymal cell
34
- support neurons
- maintain blood-brain barrier
- maintain appropriate chemical environment around neurons
Astrocyte
35
produces and maintains myelin sheath around CNS axons
oligodendrocytes
36
phagocytize microbes and damaged nervous tissue
microglia
37
- lines ventricles of the brain and spinal cord
| - produce cerebrospinal fluid
ependymal cell
38
PNS includes ___ diff types of neuroglial cells
2 types
- satellite cells
- schwann cells
39
surround cell bodies of neurons in PNS ganglia
| -support and exchange of materials
satellite cells
40
encircle axons of neurons in PNS producing a myelin sheath
Schwann cell
41
- axons of some neurons are myelinated
| - covered by a myelin sheath
myelination
42
- composed of lipids and proteins
| - electrically insulates the axon (prevents generation of action potentioal)
myelin sheath
43
myelination of PNS axons
- myelin sheath produced and maintained by Schwann cell
1. as it develops, schwann cells wrap around axon
2. portion of plasma membrane of schwann cell that wraps around the axon is the myelin sheath
44
Gaps in the myelin sheath are called
Nodes of Ranvier
45
the two types of tissue in the CNS
- white matter
| - grey matter
46
composed of mainly myelinated axons
white matter
47
composed mainly of neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia
Grey matter
48
axons of neurons are often bundled together forming
- nerves
| - tracts
49
bundles of axons located in the PNS
nerves
50
bundles of axons located in the CNS
tracts
51
resting membrane potentials exist because
there is a high concentration of Na+ outside of a cell
- Na+/K+ pumps in plasma membrane actively transport out of cell
- there are few Na+ leakage channels in plasma membrane
52
production of electrical signals depend on
- existence of a resting membrane potential
| - presence of specific ion channel
53
electrical signals are due to
flow of ions across the plasma membrane via ion channels
54
___ allow specific ions to cross the plasma membrane
ions channels
55
movement of ions creates flow of
electrical current that changes resting membrane potential
56
leakage channels
- randomly open and close
- more K+ leakage channels than Na+ channels
- plasma membrane is more permeable to K+ than Na+
57
open in response to specific chemical stimulus including: vibration, pressure, tissue stretching
-found in sensory receptors
mechanically gated channels
58
- open in response to change in membrane potential (voltage)
| - participate in generation and propagation of action potentials
voltage gated channels
59
neurons produce what two types of electrical signals
- grated potentials
- action potentials
* graded potential triggered 1st may be followed by action potential
60
- small deviation from the resting potential due to movement of ions
- vary in amplitude depending on strength of stimuli
- are local, mainly dendrites and cell body of neuron
Graded potentials
61
a series or rapid events that take place in two phases
action potential
62
what are the 2 action potential phases
- depolarization phase
| - repolarization phase
63
action potential triggered when
depolarization reaches a certain threshold (*-55mV) due to a depolarizing graded potential
-amplitude of action potential is always the same
64
generation of action potentials defined by what 5 steps
1. depolarization to threshold
2. activation of sodium channels and rapid depolarization
3. inactivation of sodium channels and activation of potassium channesl
4. closing of potassium channels
5. after hyperpolarizing phase
65
Summary of repolarizing phase
Inside of cell becomes negatively charged again (repolarized) (-70mV)
Fast-acting Na+ channels become inactivated
Slow-activating K+ channels open
66
Summary of depolarizing phase
Inside of cell becomes positively (+30 mV)
| Fast-acting Na+ channels open
67
Period during which excitable cell cannot generate another action potential
Refractory period
68
Type of refractory period where:
Na+ channels require time to return to resting state before they can open again
No amount of stimulus can generate a second action potential
Ensures that action potential moves in a single direction
Absolute refractory period
69
Type of refractory period where:
K+ channels are open
Second action potential can be generated if stimulus is larger than normal
Relative refractory period
70
When and where is the action potential generated?
at a specific point on the plasma membrane, not across entire plasma membrane at once
71
Movement of cation potential long neuron:
- From trigger zone
- Typically at junction of cell body and axon
- To axon terminals
Propagation
72
Type of propagation that has step-by-step polarization and repolarization of each region of the axon:
- Action potential at one point stimulates generation of action potential at next point
- Slow rate of propagation
- Occurs in unmyelinated axons
Continuous propagation
73
Type of propagation in which:
Few Na+ and K+ channels under the myelin sheath
Action potential cannot be generated there
Action potentials "jump" from one node of Ranvier to the next
Much more rapid propagation than continuous conduction
Saltatory propagation
74
A neuron that sends signal (synapses)
Pre synaptic neuron
75
A neuron that receives signal
Post synaptic neuron
76
Two types of synapses
Electrical synapse
| Chemical synapse
77
Type of synapse where action potential conducted directly from cell to cell via gap junctions and allows for faster communication and greater synchronization among cells
Electrical synapse
78
Type of synapse where:
- Pre- and post- synaptic cells are separated by a synaptic cleft (Filled with interstitial fluid)
- Action potential conducted across synaptic M indirectly via neurotransmitters
Chemical synapse
