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A&P Lecture Exam 2 > CH 11 > Flashcards

CH 11 Flashcards

1
Q

5 functions of the nervous system:

A 
Sensory input
Integration
Control of muscles/glands
Homeostasis
Center for mental activities
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2
Q

Sensory Input

A

Sensory receptors monitor external and internal stimuli

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3
Q

Integration

A

the brain and spinal cord process and respond to sensory input

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4
Q

Homeostasis regulates…

A

other systems to maintain a constant internal environment

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5
Q

Control of muscles and glands

A
  • Skeletal m. contract when stimulated by NS

- Smooth m., cardiac m., and glands are also under nervous control

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6
Q

center for mental activities

A

the brain is the center of mental activities including memory, emotions, thinking, and consciousness

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7
Q

Central nervous system (CNS)

A
  • composed of the brain and spinal cord

- processes, integrates, stores, and responds to information from the PNS

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8
Q

Peripheral Nervous System (PNS)

A
  • Nervous tissue external to the CNS
  • Composed of sensory receptors and nerves
  • detects stimuli and transmits information to the CNS and receives information from the CNS
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9
Q

PNS: Sensory Receptors

A

Ends of neurons or separate, specialized cells that detect: temperature, pain, touch, pressure, light, sound, odors

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10
Q

PNS: Nerve

A

-Bundle of axons and sheaths that connect CNS to sensory receptors, muscles, and glands

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11
Q

PNS: How many cranial nerves and where do they originate?

A

12; the brain

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12
Q

PNS: How many spinal nerves and where do they originate?

A

31; the spinal cord

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13
Q

PNS: Ganglion (singular)

A

collection neuron cell body located external to the CNS

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14
Q

PNS: Plexus

A

Extensive network of axons, and sometimes neuron cell bodies, located outside of the CNS

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15
Q

PNS: Sensory Division

A
  • Afferent

- Transmits action potentials from receptors to CNS

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16
Q

PNS: Motor Division

A
  • Efferent

- Transmits action potentials from CNS to effectors

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17
Q

PNS: motor division

A
  • transmits APs from the CNS to effector organs

- composed of 2 subdivisions: somatic nervous system and autonomic nervous system (ANS)

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18
Q

Somatic nervous system

A

innervates skeletal m.

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19
Q

Autonomic nervous system (ANS)

A

Innervates cardiac m.

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20
Q

Subdivisions of the ANS:

A

Sympathetic, parasympathetic, enteric

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21
Q

what does to innervate mean?

A

to form a synapse with and transmit a AP

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22
Q

PNS: Autonomic Division

A
  • Unconscious control
  • Two neuron system
  • sympathetic division
  • parasympathetic division
  • enteric division
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23
Q

PNS: Autonomic Division: Two Neuron System

A
  1. ) From CNS to ganglion

2. ) From ganglion to effector

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24
Q

PNS: Autonomic Division: Sympathetic Division

A
  • Always active at basal levels but is most active during states of heightened stress
  • Responsible for the fight or flight response
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25
PNS: Autonomic Division: Parasympathetic Division
- bring internal variables down - regulates resting functions - slows the body down
26
PNS: Autonomic Division: Enteric Division
- controls digestive activities | - housed within the digestive tract
27
Will the sympathetic and parasympathetic divisions be activated at the same time?
no, they have a push/pull type of relationship
28
CNS consists of...and corresponds with...
brain and spinal cord...PNS
29
PNS consists of...and corresponds with...
-Nervous tissue outside the CNS -Sensory receptors and nerves ... 2 way comms with CNs, talks to motor division, receives input from sensory division
30
Motor Division consists of...and corresponds with...
-carries APs away from CNS in cranial nerves or spinal nerves..... talks to ANS and somatic nervous system
31
the sensory division consists of...and corresponds with...
-transmits APs away from sensory receptors to the CNs.... | only talks to PNS
32
Somatic Nervous system consists of...and corresponds with...
-innervates skeletal m.
33
ANS consists of...and corresponds with...
innervates cardiac m., smooth m, and glands... talks to sympathetic div., parasympathetic div, and enteric nervous system
34
the sympathetic division consists of...and corresponds with...
- most active during physical activity | - fight or flight
35
the parasympathetic division consists of...and corresponds with...
- regulates resting functions | - calm/at rest
36
the enteric nervous system consists of...and corresponds with...
controls the digestive system
37
Neurons
excitable cells that receive stimuli and transmit APs to other neurons or effector organs
38
What are neurons composed of?
- cell body (soma) - dendrites - axons
39
Dendrites
receive incoming information
40
axons
send outgoing information
41
Neuroglia (glial cells)
- non-neural cells - cells that surround and support the functions of neurons - account for over half of the brain's weight
42
Neuron: Cell body (soma)
- contains the nucleus, nucleolus, and nissl substance | - mitochondria, golgi apparatus and other organelles are present
43
Neuron: Dendrites
Short, branched cytoplasmic extensions of the cell body | -conduct electric signals toward the cell body
44
Neuron: Axon
- cytoplasmic extension of the cell body | - transmit APs to other cells
45
Nissl substance
- an aggregate of rough ER and free ribosome | - primary site of protein synthesis in the neutron
46
what are clusters of cell bodies in the CNS called?
nuclei
47
what are clusters of cell bodies in the PNS called?
ganglia
48
Neuron Structure: Axon
- Trigger zone - Most neurons have one un-branched axon (most branches, if present, are called collateral axons) - presynaptic terminal
49
Trigger Zone
- Part of the neuron where the axon originates | - APs are generated here
50
Presynaptic Terminal
- branched terminus of an axon (10,000 or more) - form synapses - contain vesicles with neurotransmitters
51
What are the 3 categories that neurons are classified into according to the direction in which APs are conducted:
- sensory (afferent) neurons - motor (efferent) neurons - interneurons (association)
52
sensory (afferent) neurons
conduct APs towards the CNS
53
motor (efferent) neurons
conduct APs away from CNS, towards muscles or glands
54
interneurons (association)
conduct APs from one neuron to another neuron within the CNS
55
What are the 3 categories that neurons are classified into according to the number of processes that extend from the neuron cell body
- multipolar - bipolar - unipolar
56
multipolar
- have several dendrites and a single axon | - interneurons and motor neurons
57
Bipolar
- Have a single axon and dendrite | - components of sensory organs
58
Unipolar
- Have a single axon | - most sensory neurons
59
Neuroglia
- provide a supportive scaffolding for neurons - segregate and insulate neurons - guide young neurons to the proper connections - promote health and growth
60
Neuroglia of the CNS
- astrocytes - microglia - ependymal cells - oligodendrocytes
61
Neuroglia of the PNS
- satellite cells | - schwann cells
62
Neuroglia of the CNS: Astrocytes
- cling to neurons and cover capillaries - support and brace neurons and blood vessels - influence the functioning of the blood-brain barrier - regulate what substances reach the CNS from the blood
63
Neuroglia of the CNS: Astrocytes: Blood Brain Barrier
- protects neurons from toxic substances - allows the exchange of nutrients and waste products between neurons and blood - prevents fluctuations in the composition of the blood from affecting the functions of the brain - lipid soluble can get through; imperfect
64
Neuroglia of the CNS: Ependymal Cells
- line the ventricles of the brain and the central canal of the spinal cord - some are specialized to form choroid plexuses
65
Neuroglia of the CNS: Ependymal Cells: Choroid plexuses
- found within certain regions of ventricles - secrete cerebrospinal fluid - cilia help move fluid through the cavities of the brain
66
Neuroglia of the CNS: Microglia
- specialized macrophages - become mobile and phagocytic in response to inflammation - phagocytes monitor the health of neurons
67
Phagocytize
- necrotic tissue (dead and damaged neurons) - microorganisms - foreign substances that invade the CNS
68
Neuroglia of the CNS: Oligodendrocytes
- form myelin sheaths around the axons of CNS neurons | - a single Oligodendrocyte can form myelin sheaths around portions of several axons
69
Neuroglia of the PNS: Schwann Cells (nuerolemmocytes)
- form myelin sheath around part of the axon of a PNS neuron | - unlike Oligodendrocytes, schwann cells form a myelin sheath around a portion of only one axon
70
Neuroglia of the PNS: Satellite Cells
- support and nourish neuron cell bodies within ganglia | - protect neurons from heavy metal poisons by absorbing them and reducing their access to neuron cell bodies
71
Axon: Myelinated
- The PM of a schwann cells or Oligodendrocyte repeatedly wraps around a segment of an axon to form the myelin sheath - conducts APs rapidly - Node of ranvier
72
Myelin and its functions
- whitish, fatty, segmented sheath around most long axons - protection - electrically insulates - increases the speed of nerve - impulse transmission
73
Node of Ranvier
Gap in the myelin sheath
74
Axons: Un-myelinated
- rest in invaginations of Schwann cells or oligodendrocytes - surround each axon, but don't wrap around it many times - conduct APs slowly
75
Nervous tissue is organized into what 2 categories...
white matter and gray matter
76
White matter
- myelinated axons - propagates APs - forms nerve tracts in the CNS and nerves in the PNS
77
Gray Matter
- collections of neuron cell bodies, un-myelinated axons, dendrites, neuroglia - forms cortex and nuclei in the CNS and ganglia in the PNS - integrative functions
78
Action potentials are...
electrical signals produced by cells
79
When APs are received from sensory cells...
it can result in sensations of sight, hearing and touch
80
Electrical properties of cells result from:
- ionic concentration difference across the PM | - permeability characteristics of the PM
81
What is in greater concentration outside of the cell?
Na+ (sodium) Ca2+ (calcium) Cl- (chloride)
82
what is in greater concentration inside of the cell?
K+ (potassium) | negatively charged molecules, such as proteins
83
Negatively charged proteins are synthesized....
inside of the cell and cannot diffuse out of it
84
Concentration gradients result from:
1. ) Na/K pump | 2. ) Permeability characteristics of the PM
85
Na/K Pump:
- moves ions by active transport | - K+ are moved int he cell while Na+ are moved out of the cell
86
Leak channels
- always open - K+ leak channels are more numerous than Na leak channels - PM is more permeable to K+ than to Na+ when at rest
87
Gated ion channels
include ligand gated ion channels, voltage gated ion channels and other gated ion channels
88
Electrical Signals: Gated ion Channels
- Open and close in response to stimuli | - change permeability of the cell membrane when opened
89
Ligand-gated ion channels
- open or close with the biding of a specific ligand (neurotransmitters) - common in glands and nervous and muscles tissue
90
Ligand
a molecule that binds to a receptor
91
Receptor
a protein or glycoprotein that has a receptor site to which a ligand can bind
92
voltage gated ion channels
- open and close in response to small voltage changes across the PM - abundant in nervous and muscle tissue
93
Other gated ion channels open and close in response to...
physical deformation of receptors | touch receptors, temperature receptors
94
Touch Receptors
respond to mechanical simulation
95
temperature receptors
respond to temperature changes
96
At RMP, the inside of the cell is negatively charges compared to the outside of the cell..how?
due mainly to the tendency of positively charged K+ to diffuse out of the cell, opposed to the negative charge that develops inside the PM
97
T/F: Na+, Cl- and Ca2+ do not have a great impact on the RMP
True, there are few leakage channels for these ions | -if leakage channels alone were responsible for RMP, Na and K concentrations would eventually equalize.
98
RMP is maintained by the...
Na/K Pump
99
When is the RMP established?
when the movement of K+ out of the cell is equal to their movement into the cell
100
Depolarization
- a decrease in the RMP (less polar) | - movement of RMP toward zero, becomes less negative
101
What causes depolarization?
- Decrease in the K+ concentration gradient - decrease in membrane permeability to K+ - increase in membrane permeability to Na+ or Ca2+ - decrease in extracellular Ca2+ concentrations
102
What is the opposite of depolarization?
Hyper-polarization... NOT re-polarization
103
Hyperpolarization
- increase in the RMP (more polar) | - movement of RMP further away from zero
104
What causes hyper-polarization?
- increase in the K+ concentration gradient - increase in membrane permeability to K+, Cl- - decrease in membrane permeability to Na+ - increase in extracellular Ca2+ concentrations
105
Electrical signals: graded potentials
- do not reach threshold - smaller changes in the RMP - confined to a small area of the PM
106
An increase in the membrane permeability to Na+ can cause...
a graded depolarization
107
An increase in the membrane permeability to K+ or Cl- can result in...
graded hyperpolarization
108
Action potential
- larger change in RMP that can spread over the entire surface of the cell - starts with a graded depolarization to a level called threshold
109
APs occur in what 3 phases:
Depolarization Re-polarization Afterpotential
110
APs occur in...
all or none fashion and are of the same magnitude, no matter how strong the stimulus
111
AP Phases: Depolarization
Na diffused into the cell through voltage-gated ion channels
112
AP Phases: Repolarization
- voltage-gated Na channels close | - Voltage-gated K channels open and K diffuses out of the cell
113
AP Phases: Afterpotential
a brief period of hyperpolarization following repolarization
114
Absolute refractory period
- the time during an AP when a second stimulus (no matter how strong) cannot initiate another AP - completely insensitive to another stimulus
115
relative refractory period
the time during which a stronger-than-threshold stimulus can evoke another AP
116
AP: Frequency
number of APs produced per unit of time in response to stimuli
117
4 types of stimulus:
subthreshold threshold submaximal maximal or supramaximal
118
subthreshold stimulus
produces a graded depolarization
119
threshold stimulus
produces a single AP
120
submaximal stimulus
produces an increasing frequency of APs as the strength of the stimulus increases
121
maximal or supramaximal stimulus
produces a maximum frequency of APs
122
Can we produce a "greater" AP?
No, but we can produce a higher frequency; all APs have the same magnitude
123
what does RMP sit at?
-70
124
APs generate ionic currents that stimulate..
voltage-gated Na channels in adjacent regions of the PM to open---> leads to the production of new APs
125
Propagation occurs most rapidly in...
myelinated, large-diameter axons
126
reversal of the direction of AP propagation is prevented by...
- the absolute refractory period | - prevents the ionic current from stimulating the production of an AP in the reverse direction
127
APs: Propagation: Saltatory Conduction
- in myelinated axons, APs from one node of ranvier generate ionic currents that flow toward the next node of ranvier - currents appear to jump from one node of ranvier to the next; allows us to send APs rapidly
128
in a myelinated axon, APs are generated at...
successive nodes of ranvier
129
what moves faster, unmyelinated or myelinated?
myelinated; unmyelinated takes baby steps, not jumps
130
in unmyelinated axons...
APs are generated immediately adjacent to previous APs

A&P Lecture Exam 2 (8 decks)

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