Chapter 3 Flashcards
What 2 things compose the central nervous system?
- Brain
- Spinal cord
What is the term referred to as neurons responding to stimuli and converting those messages to an electrical signal?
Nerve impulse
What is the basic structural unit of the nervous system?
Neuron
The neuron has ______ major regions.
3
What are the 3 major
What are the roles of the cell body?
- Contains nucleus
- Cell processes radiate out
What are the roles of dendrites?
- Recever cell processes
- Carry impulse toward cell body
What are the jobs of the axon?
- Sender cell process
- Starts at axon hillock
- End branches
- Axon terminals
Sensory is referred to as _________ signals.
Incoming
Motor is referred to as ______ signals.
Outgoing
Somatic is referred to as ______ to skeletal muscles
Voluntary
Autonomic is referred to as _______ to viscera.
Involuntary
What are the 3 MUST’s for the electrical signal between periphery and brain?
- Must be generated by a stimulus
- Must be propagated down an axon
- Must be transmitted to next cell in line
T/F: Difference in electrical charges between outside and inside of the cell.
True
T/F: The inside of the resting membrane potential is more negative relative to the outside.
True
What is the negative charge on the inside of the cell?
-70mV
What are the two causes for the inside of the cell being more negative than the outside?
- High Na outside cell
- Medium K+ Inside cell
When charges across the membrane differ, the membrane is ______.
Polarized
RMP is maintained in what 2 ways?
- Membrane more permeable to K+ due to open K+ channels
- Na+ - K+ pump (primary mechanism)
What occurs when inside of cell becomes less negative?
Depolarization
What is the term when more Na+ channels open, and Na+ enters the cell?
Influx
What is required for nerve impulse to arise and travel?
Depolarization
What occurs when the inside of the cell becomes more negative?
Hyperpolarization
What is the term used when more K+ channels open and K+ leaves the cell?
Efflux
What makes it more difficult for nerve impulse to arise?
Hyperpolarization
What is Repolarization?
The return to RMP (Resting Membrane Potential) (-70mV)
In what 2 ways does depolarization and Hyperpolarization contribute to the nervous system function? (G, C)
- Graded Potentials
- Can excite or inhibit a neuron
What are localized changes in membrane potential?
Graded potentials (GPs)
How are Graded Potentials (GPs) generated?
Incoming signals from dendrites
How do GPs help the cell body?
Help by decking whether to pass a signal on
What happens during Excitatory postsynaptic potential (EPSP)?
- Na+ channels open = Na+ influx
- Depolarization
What happens during the inhibitory postsynaptic potential (IPSP)?
- K+ channels open = K+ efflux
- Hyperpolarization
Strong ________ will lead to an ____________.
EPSP ; Action potential
What are 4 facts along with a strong EPSP leading to an AP? (R,L,A,M)
-Rapid depolarization of neurons membrane
- Last - 1 ms
- AP will be propagated down axon & transmitted to next cell
- Must reach a threshold mV
If GP reaches _____ mV to _____ mV, ______ will occur
-55, -50, AP
What is the principle that refers to this statement:
“Threshold mV not reached, then no AP”
All-or-none principle
What keeps total of EPSPs & IPSPs?
Axon hillock
State the process/stage when given the mV:
-70 to -55mV: ____________, ________
-55 to +30mV: ____________, ________
+30 to -70mV: ____________, ________
Depolarizing GP, Na+ influx
Depolarizing AP, Na+ influx
Repolarizing AP, K+ efflux
What 2 characteristics determine propagation speed down an axon?
- Axon diameter
- Myelin
A ______ axon = a _________ propagation speed
Larger ; faster
The myelin’s fatty sheath around an axon is formed by what?
Schwann cells
Within the myelin, what are the non-continous spaces?
Nodes of ranvier
What speeds up propagation?
Saltatory conduction
What is the degeneration of myelin; loss of coordination?
Multiple sclerosis
For neurons to communicate, APs transfer form a _________ to _______ neuron.
Presynaptic ; postsynaptic
What is the site of neuron-to-neuron communication?
Synapse
T/F: AP must travel across synapse.
True
Give the pathway of transmitting AP’s.
Presynaptic axon terminal ——> synapse——> postsynaptic dendrites
T/F: signal changes form across synapse
True
T/F: the correct sequence for neuron-to-neuron communication is:
Electrical ——> chemical ——> electrical
True
AP can only move in _______ direction(s).
One
Axon terminals contain _________.
Neurotransmitters
What are neurotransmitters?
Chemical messengers
________ bind to receptor on postsynaptic surface.
Neurotransmitters
Neurotransmitters stimulate _______ in postsynaptic neuron.
GP’s
T/F: If depolarization reaches threshold, AP occurs, and the process does not continue.
False; it does continue
What is the site of neuron-to-muscle communication?
Neuromuscular junction
The neuromuscular junction uses _________ as its neurotransmitter.
Acetylcholine (ACh)
Postsynaptic cell in the neuromuscular junction is a what?
Muscle fiber
ACh binds to receptor at special site also known as the ________?
Motor end plate
There are _______ known or suspected neurotransmitters.
50+
Neurotransmitters fall into what 2 categories?
Small-molecule, rapid acting
Large-molecule (neuropeptides), slow-acting
ACh and norepinephrine govern ______.
Exercise
ACh stimulates ________, and mediates ___________ nervous system effects.
Skeletal muscle contraction ; parasympathetic
NE mediates ______ nervous system effects.
Sympathetic
The brain is divided into what 4 segments?
- Cerebrum
- Diencephalon
- Cerebellum
- Brain Stem
What lobe is the primary motor cortex of the brain?
Frontal love
The frontal lobe provides conscious control of __________ movement.
Skeletal muscle
Neurons in the frontal lobe are called ________.
Pyramidal cells
What part of the brain is where decisions are made about movement?
Frontal lobe
The Diencephalon contains what 2 segments of the brain?
- Thalamus
- Hypothalamus
What is the sensory relay center of the brain?
Thalamus
All sensory input enters the thalamus besides ______.
Smell
The thalamus regulates what sensory ______ reaches the conscious brain.
Input
________ determines what we are consciously aware of.
Thalamus
What portion of the brain maintains homeostasis?
Hypothalamus
The cerebellum is located where?
Behind the brain stem
Which portion of the brain controls rapid, complex movements?
Cerebellum
T/F: The thalamus coordinates timing, sequence of movements.
False; its the cerebellum
T/F: The cerebellum compares actual to intended movements and initiates correction.
True
The ________ relays information (both ways) between brain and spinal cord.
Brain stem
The brainstem is composed of what 3 things?
-midbrain
-pons
-medulla oblongata
_______ is the most common form of dementia?
Alzheimer’s
T/F: Tau and beta amyloid are contributions to Alzheimer’s.
True
Astrocyte and microglia
What portion of the brain is first affected by Alzheimer’s?
Hippocampus
_______ is continuous with medulla oblongata.
Spinal Cord
The spinal cord is composed of tracts of nerve fibers that permit _____________ of nerve impulses.
Two-way conduction
What connects the CNS to PNS?
Spinal Cord
The _______ connects to brain and spinal cord via ____ pairs of nerves.
43
Both cranial and spinal nerves directly supply _____________.
Skeletal muscle s
__________ transmits information from periphery to brain
Sensory division
What receptors are located in join capsules?
Joint kinesthetic receptors
Joint kinesthetic receptors are sensitive to ________ & _________.
Joint angles & rate of angle change
T/F: Joint Kinesthetic receptors can sense joint position and movement
True
Muscle spindles are sensitve to _________ & ______.
Muscle length / rate of length change
Golgi tendon organs are sensitive to _________ applied by muscle to its tendon.
Tension
T/F: Golgi tendon organs provide information about strength of contraction
True
The Motor division transmits information from ____ to ___.
brain ; periphery
Autonomic controls _____ internal functions.
Involuntary
What are 3 examples of exercise related autonomic regulation? (HrBpLf)
Heart rate
Blood pressure
Lung function
What are the 2 complementary divisions of the autonomic nervous system?
Sympathetic & parasympathetic nervous system
Sympathetic is also referred to as ________.
Fight or flight
Parasympathetic is also referred to as ______.
Rest and digest
Which complementary autonomic division prepares the body for exercise?
Fight or flight
Which complementary autonomic division is active at rest?
Rest and digest
_________ is the process of communication and interaction between sensory and motor systems.
Sensory-Motor Integration
There are ____ sequential steps in sensory motor integration.
5
There are ____ sequential steps in sensory motor integration.
5
_________ can be integrated at many points in CNS
Sensory input
T/F: Sensory input complexity of integration increases with ascent through CNS.
True
________ is the fastest mode of response.
Motor reflex
T/F: Motor reflex impulse travels up to the brain.
False; it ends in spinal cord
Reflexes are ____,______ responses to a given stimulus.
Instant
Preprogrammed
T/F: motor reflex occurs before conscious awareness.
True
Muscle Spindles are a group of ____ - ____ small, specialized ___________.
4-20; intrafusal muscle fibers
Muscle Spindles are innervated by _________.
Y-motor neurons
The _________ of the muscle spindles contains no or few actin and myosin.
Central region
GTO is a sensory receptor embedded in a _______.
Tendon
There are ___ to ____ muscle fibers attached to each GTO
5-25
GTO are sensitive to ________.
Tension
________ are important in resistance exercise.
GTO
When stimulated by excessive tension, GTO’s:
- I
- S
-R
Inhibit agonists
Safety mechanism that prevents excessive tension
Reduce potential for injury in resistance exercise
_________ neuron carries AP to muscle.
a-motor
T/F: During a motor response, AP spreads to muscle fibers of motor unit
True
What are the two types of motor control?
Fine & Gross
Extra-ocular muscles have a innervation ration of __:__.
1:15
Gastrocnemius has a innervation ratio of __:__.
1:2000
Gastrocnemius has a innervation ratio of __:__.
1:2000
Motor response is a _______ of motor units.
Homogeneity