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163 Cards in this Set

  • Front
  • Back
2 Types of Neural Tissue Cells
Neurons
Neuroglia
Cells that can send and receive signals
Neurons
Cells that support and protect neurons
Neuroglia
Neuroglia AKA
glial cells
2 Anatomical Divisions of the Nervous System
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
System that consists of the spinal cord and brain
Central Nervous System
System that contains Neural Tissue, Connective Tissues & Blood Vessels
Central Nervous System
Functions of this system
processes and coordinates:
a) sensory data: from inside & outside body
b) Motor commands
c) higher functions of the brain
Central Nervous System
System which includes all neural tissue outside the CNS
Peripheral Nervous System
Functions of this System:
1) Deliver sensory info to CNS
2) Carry motor commands to peripheral tissues & systems
Peripheral Nervous System
Bundles of axons with connective tissues and blood vessels
Nerves (peripheral nerves)
These carry sensory information and motor commands in PNS
Nerves
Nerves which connect to brain
cranial nerves
Nerves which attach to spinal cord
spinal nerves
2 Functional Divisions of the PNS
Afferent Division
Efferent Division
Function of this division of the PNS:
carries sensory info from PNS receptors TO CNS
Afferent Division
Function of this division of the PNS:
Carries motor commands FROM CNS to PNS muscles and glands
Efferent Division
Afferent Division: These
a) detect changes or respond to stimuli
b) neurons and specialized cells
c)complex sensory organs (eg. eyes, ears)
Receptors
Afferent Division: These
a) respond to efferent signals
b) cells and organs
Effectors
2 Systems in the efferent division of the PNS
1) Somatic Nervous System (SNS)
2) Autonomic Nervous System (ANS)
This PNS system controls skeletal muscle contractions: voluntary and involuntary (reflexes)
Somatic Nervous Stystem
This PNS system:
controls subconscious actions: contractions of smooth/ cardiac muscle and glandular secretions
Autonomic Nervous System
2 Divisions of the Autonomic Nervous System
1) Sympathetic division
2) Parasympathetic Division
This division of the Autonomic Nervous System has a stimulating effect.
sympathetic division
This division of the Autonomic Nervous System has a relaxing effect.
parasympathetic division
This type of neuron is common in the CNS
multipolar neuron
Name this Neuron
Name this Neuron
Multipolar Neuron
Type of neuron with:
a) cell body (soma)
b) short, branched dendrites
c) long, single axon
multipolar neuron
Location of these in neuron
a) large nucleus and nucleolus
b) perikaryon (cytoplasm)
c) mitochondria (produce ATP)
d) RER and ribosomes (produce neurotransmitters)
e) Cytoskeleton
Cell body
This part of the neuron cell body is made of neurofilaments, neurotubules and neurofibrils.
The cytoskeleton
Bundles of neurofilaments that provide support for dendrites and axon
Neurofibrils
Provide support for dendrites and axon
Neurofibrils
Dense areas of RER & ribosomes that make neural tissue appear gray (gray matter)
Nissl bodies
This part of the neuron receives info from other neurons and is 80-90% of the neurons surface
Dendritic spines
Long part of neuron that carries electrical signal (action potential) to target

**critical to function
Axon
Structures of _________
a) axoplasm
b) axolemma
c) axon hillock
d) initial segment
axon structures
cytoplasm of the axon
axoplasm
These are located in which part of the neuron?
a) neurotubules
b) neurofibrils
c) enzymes
d) organelles
axoplasm
Specialized cell membrane which covers axoplasm
axolemma
Thick section of axon cell body which attaches initial segment
axon hillock
structure of axon which attaches to axon hillock
initial segment
A) Dendritic Branches
B) Bissl Bodies (RER & free ribosomes)
C) Mitochondrion
D) Axon Hillock
E) Initial Segment of Axon
F) Golgi Apparatus
G) Neurofilament
H) Nucleus
I) Nucleolus
J) Dendrite
Area where a neuron communicates w/ another cell
synapse
neuron that sends message
presynaptic cell
neuron that receives message
postsynaptic cell
the small gap that seperates the presynaptic membrane and the postsynaptic membrane
synaptic cleft
expanded area of axon of the presynaptic neuron
synaptic knob
Contains synaptic vesicles of neurotransmitters
synaptic knob
chemical messengers which
a) are released at presynaptic cleft
b) affect receptors of postsynaptic membrane
c) are broken down by enzymes
d) are reassembled at synaptic knob
neurotransmitters
2 Types of synapses
1) neuromuscular junction
2) neuroglandular junction
synapse between neuron and muscle
neuromuscular junction
synapse between neuron and gland
neuroglandular junction
Structures of a typical synapse
Structures of a typical synapse
A) Telodendrion
B) Synaptic Bulb
C) Mitochondrion
D) Synaptic Vesicles
E) Precynaptic membrane
F) Postsynaptic membrane
G) Synaptic Cleft
H) Endoplasmic Reticulum
Four Structural Classifications of Neurons
Anaxonic neurons
Bipolar neurons
Unipolar neurons
Multipolar neurons
Type of neuron found in brain and sense organs
Anaxonic neurons
Type of neuron found in special sensory organs (sight, smell, hearing)
Bipolar neurons
Type of neuron found in sensory neurons of PNS
Unipolar neurons
Neurons common in the CNS and
Include all skeletal muscle motor neurons
Multipolar neurons
Name the neuron
Small
All cell processes look alike
Anaxonic Neurons
Name the Neuron
Are small
One dendrite, one axon
Bipolar Neurons
Name the Neuron
Have very long axons
Fused dendrites and axon
Cell body to one side
Unipolar Neurons
Name the Neuron
Have very long axons
Multiple dendrites, one axon
Multipolar Neurons
Name the Neuron
Name the Neuron
Anaxonic
Bipolar
Unipolar
Multipolar
3 Functional Classifications of Neurons
Sensory neurons
Motor neurons
Interneurons
Functions of which type of Neuron
1) Monitor internal environment (visceral sensory neurons)
2) Monitor effects of external environment (somatic sensory neurons)
Sensory Neuron Functions
Structures of which type of neuron

1) Unipolar
2) Cell bodies grouped in sensory ganglia
3) Processes (afferent fibers) extend from sensory receptors to CNS
Sensory Neuron Structures
Neuron that carries instructions from CNS to peripheral effectors Via efferent fibers (axons)
Motor Neurons
Two major efferent systems
Somatic nervous system (SNS
Autonomic (visceral) nervous system (ANS)
This efferent system includes all somatic motor neurons that innervate skeletal muscles
Somatic nervous system
This efferent system:
visceral motor neurons innervate all other peripheral effectors (e.g., smooth muscle, cardiac muscle, glands, adipose tissue)
Autonomic (visceral) nervous system
Most of these neurons are located in brain, spinal cord, and autonomic ganglia between sensory and motor neurons
Interneurons
These neurons are responsible for:
1) distribution of sensory information
2) coordination of motor activity
Interneurons
These neurons are involved in higher functions
Memory, planning, learning
Interneurons
Half the volume of the nervous system is made of?
Neuroglia
Four Types of Neuroglia in the CNS
Ependymal cells
Astrocytes
Oligodendrocytes
Microglia
cells with highly branched processes; contact neuroglia directly
Ependymal cells
large cell bodies with many processes
Astrocytes
smaller cell bodies with fewer processes
Oligodendrocytes
smallest and least numerous neuroglia with many fine-branched processes
Microglia
These neuroglia cells form epithelium called ependyma
Ependymal cells
These neuroglia cells Line central canal of spinal cord and ventricles of brain
Ependymal cells
These neuroglia cells secrete cerebrospinal fluid (CSF)
Ependymal cells
These neuroglia cells have cilia or microvilli that circulate CSF
Ependymal cells
These neuroglia cells monitor CSF
Ependymal cells
These neuroglia cells contain stem cells for repair
Ependymal cells
These neuroglia cells Maintain blood–brain barrier (isolates CNS)
Astrocytes
These neuroglia cells Create three-dimensional framework for CNS
Astrocytes
These neuroglia cells Repair damaged neural tissue
Astrocytes
These neuroglia cells Guide neuron development
Astrocytes
These neuroglia cells Control interstitial environment
Astrocytes
Processes contact other neuron cell bodies
Oligodendrocytes
These neuroglia cells Wrap around axons to form myelin she
Oligodendrocytes
A) satellite cells
B) Schwann cells
C) Oligodendrocytes
D) Astrocytes
E) Microglia
F) Ependymal Cells
Neuroglia in the CNS
Neuroglia in the CNS
A) Central Canal
B) Ependymal Cells
C) Gray Matter
Neuroglia in the CNS
Neuroglia in the CNS
A) Gray Matter
B) Neurons
C) Microglial Cell
D) Central Canal
E) Ependymal Cells
Oligodendrocyte feature which:
1) increases speed of action potentials
2) insulates "_____" axons
3) makes nerves appear white
myelination
myelinated segments of axon in Oligodendrocytes
internodes
Oligodendrocytes
gaps between internodes where axons may branch
nodes (also called nodes of Ranvier)
Schwann Cells and Peripheral Axons
Schwann Cells and Peripheral Axons
A) nucleus
B) axon hilock
C) Axon
D) myelynated internode
E) Axon
F) Axolemma
G) Myelin covering internode
H) nodes
I) initial segment (unmyelinated)
J) Schwann cell of nucleus
K) axon
L) neurilemma
M) dendrite
N) neurilemma
O) axon
P) myelin
Type of Neuroglia in the CNS
Myelination
White matter
Gray matter
Oligodendrocytes
regions of CNS with many myelinated nerves
White matter
unmyelinated areas of CNS
Gray matter
Types of Neuroglia in the CNS
Migrate through neural tissue

Clean up cellular debris, waste products, and pathogens
Microglia
Masses of neuron cell bodies surrounded by neuroglia
found in the PNS
Ganglia
Also called amphicytes
Satellite cells
Surround ganglia and regulate environment around neuron
Satellite cells
Also called neurilemmocytes
Schwann cells
Form myelin sheath (neurilemma) around peripheral axons
Schwann cells
____#____ Schwann cell sheaths ___#____ segment of axon and _________Schwann cells sheath entire axon
1
1
many
These cells perform all communication, information processing, and control functions of the nervous system
neurons
These cells preserve physical and biochemical structure of neural tissue and are essential to survival and function of neurons
Neuroglia
All plasma (cell) membranes produce electrical signals by what?
ion movements
The transmembrane potential of resting cell
Resting potential
an electrical impulse
Action potential
Produced by graded potential
Action potential
Propagates along surface of axon to synapse
Action potential
Releases neurotransmitters at presynaptic membrane
Produces graded potentials in postsynaptic membrane
Synaptic activity
Response (integration of stimuli) of postsynaptic cell
Information processing
Overview of Neural Activities
Overview of Neural Activities
A) Resting potential
B) graded potential
C) action potential
D) synaptic activity
E) information processing
Three Requirements for Transmembrane Potential
1) Concentration gradient of ions (Na+, K+)
2) Selectively permeable through channels
3) Maintains charge difference across membrane (resting potential –70 mV)
2 types of Passive Forces Acting Across the Membrane
Chemical gradients
Electrical gradients
Name the gradient type
Concentration gradients of ions (Na+, K+)
Chemical gradients
Name the gradient type
Separate charges of positive and negative ions
Result in potential difference
Electrical gradients
Check summary table 12-1 slide 50 Ch. 12
Check summary table 12-1 slide 50 Ch. 12
What happens in response to temporary changes in membrane permeability resulting from opening or closing specific membrane channels
Changes in Transmembrane Potential; Transmembrane potential rises or falls
Channels that are always open permeability changes with conditions
Passive channels (also called leak channels)
Channels that open and close in response to stimuli
at resting potential, most of these channels are closed
Active channels (also called gated channels)
Three Classes of Gated Channels
Chemically gated channels
Voltage-gated channels
Mechanically gated channels
Channels that open in presence of specific chemicals (e.g., ACh) at a binding site found on neuron cell body and dendrites
Chemically gated channels
These channels:
1) respond to changes in transmembrane potential
2) Have activation gates (opens) and inactivation gates (closes)
3) Characteristic of excitable membrane
4) Found in neural axons, skeletal muscle sarcolemma, cardiac muscle
Voltage-gated channels
These channels:
Respond to membrane distortion
Found in sensory receptors (touch, pressure, vibration)
Mechanically gated channels
Where are Chemically gated channels found?
on neuron cell body and dendrites
Where are Voltage-gated channels found?
in neural axons, skeletal muscle sarcolemma, cardiac muscle
Where are Mechanically gated channels found?
in sensory receptors (touch, pressure, vibration)
Also called local potentials
Graded Potentials
Name the type of potential
Changes in transmembrane potential that cannot spread far from site of stimulation
Graded Potentials
Any stimulus that opens a gated channel produces what type of potential?
graded potential
Opening sodium channel produces graded potential:
resting membrane exposed to chemical
sodium channel opens
sodium ions enter the cell
transmembrane potential rises
What occurs?
depolarization
A shift in transmembrane potential toward
0 mV
Depolarization
Depolarization occurs when
movement of ______ through channel
produces _________
depolarizes nearby ___________ (graded potential)
change in potential is __________to stimulus
Na+
local current
plasma membrane
proportional
check slide 59 table 12-2
check slide 59 table 12-2
When the stimulus is removed, transmembrane potential returns to normal
Repolarization
Increasing the negativity of the resting potential
Result of opening a potassium channel
Opposite effect of opening a sodium channel
Positive ions move out, not into cell
Hyperpolarization
A) depolarization
B) repolarization
C) hyperpolarization
Effects of graded potentials
1) At cell dendrites or cell bodies
2) At motor end plate
1) trigger specific cell functions
2) releases ACh into synaptic cleft
What is the All-or-none principle in Initiating Action Potential?
1) Action potential is either triggered, or not
2) If a stimulus exceeds threshold amount:
the action potential is the same no matter how large the stimulus
Four Steps in the Generation of Action Potentials
Step 1: Depolarization to threshold
Step 2: Activation of Na+ channels
Step 3: Inactivation of Na+ channels, activation of K+ channels
Step 4: Return to normal permeability
During Step 2 (Activation of Na+ channels) of generation of action potentials, what happens?
Rapid depolarization
Na+ ions rush into cytoplasm
Inner membrane changes from negative to positive
How does Step 3 (Inactivation of Na+ channels, activation of K+ channels) of generation of action potentials happen?
At +30 mV
Inactivation gates close (Na+ channel inactivation)
K+ channels open
Repolarization begins
In the Generation of Action Potentials, how does
Step 4: "Return to normal permeability" happen?
K+ channels begin to close:
when membrane reaches normal resting potential (–70 mV)
K+ channels finish closing:
membrane is hyperpolarized to -90 mV
transmembrane potential returns to resting level:
action potential is over
the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following excitation
refractory period
Name the time period:
Sodium channels open or inactivated
No action potential possible
Absolute refractory period
Name this time period:
Membrane potential almost normal
Very large stimulus can initiate action potential
Relative refractory period
_____________ of Action Potentials
Moves action potentials generated in axon hillock
Along entire length of axon
A series of repeated actions, not passive flow
Propagation of Action potentials
Two methods of propagating action potentials
1) Continuous propagation: unmyelinated axons
2) Saltatory propagation: myelinated axons
Name the type of propagation

1) Action potential along myelinated axon
2) faster and uses less energy than continuous propagation
3) Myelin insulates axon, prevents continuous propagation
4) Local current “jumps” from node to node
5) Depolarization occurs only at nodes
Saltatory Propagation
Figure 12–16 Saltatory Propagation along a Myelinated Axon (Steps 1 and 2).
Figure 12–16 Saltatory Propagation along a Myelinated Axon (Steps 1 and 2).
What can effect action potential speed?

Larger equals what?
Axon diameter

Larger diameter= lower resistance
Any synapse that releases ACh is what type?
Cholinergic Synapses
4 Locations of Cholinergic Synapses
1) All neuromuscular junctions with skeletal muscle fibers
2) Many synapses in CNS
3) All neuron-to-neuron synapses in PNS
4) All neuromuscular and neuroglandular junctions of ANS parasympathetic division
Events at a Cholinergic Synapse
1) ______ arrives, depolarizes __________
2) ______ enter ________, trigger _________ of Ach
3) ACh binds to _____, depolarizes __________ membrane
4) AChE breaks ACh into _______and _________
1) Action potential, synaptic knob
2) Calcium ions, synaptic knob, exocytosis
3) receptors, postsynaptic membrane
4) acetate, choline
Figure 12–17 slides 80-83
Figure 12–17 slides 80-83
Other than acetylcholine, name 4 important Neurotransmitters
Norepinephrine (NE)
Dopamine
Serotonin
Gamma aminobutyric acid (GABA)