Ch.5? Flashcards
Neurons respond to … and convert those messages to an ….
called a nerve impulse
Stimuli, electrical signals
What makes up the CNS?
Brain
Spinal cord
Afferent and Efferent nerves in PNS
Sensory: incoming
Motor: outgoing
PNS: Somatic is … to skeletal muscles
Voluntary
PNS: Autonomic is … to viscera
Involuntary
Basic structural unit of nervous system
Neuron
3 major regions of Neuron
Cell body
Dendrites
Axon
Neuron: Cell body contains …. And cell processes radiate …
Nucleus
Out
Neuron: Dendrites are … cell process and carry impulse … body
Receiver
Toward
Neuron: Axon is a … cell process and starts at…
Acceptor
Axon hillock
TF: Axons are the end branches
True
TF: Electrical signal for communication between the periphery and brain must be generated by axon
False
Stimulus
TF: Electrical signal for communication between the periphery and brain must be propagated down an axon
True
TF: Electrical signal for communication between the periphery and brain must be transmitted to every other cell
False
Next cell in line
Difference in electrical charges between outside
and inside of cell
Resting Membrane Potential
What is the mV inside cell?
-70mV
Cause of negative mV within cell
Uneven separation of charged ions
TF: There is High Na+ outside cell and High K+ inside cell
False
Medium K+
TF: When charges across membrane differ,
membrane is polarized
True
Two ways RMP is maintained
1.Membrane more permeable to K+ due to open K+ channels
2. Na+-K+ pump (primary mechanism)
Na+-K+ pump actively transports … Na+ out of cell and … K+ into cell
3
2
TF: Na+-K+ pump needs ATP to transport molecules
True
Results of maintaining RMP
Occurs when inside of cell (-70mV) becomes less negative & More Na+ channels open, Na+ enters cell (influx)
Depolarization
Occurs when inside of cell becomes MORE negative,
even below -70 mV & More K+ channels open, K+ leaves cell (efflux)
Hyperpolarization
TF: Depolarization is required for nerve impulse to arise and travel
False
Hyper polarization
TF: Hyperpolarization makes it more difficult for nerve impulse to arise
Review: What cause rise in Na+
Depolarization
Review: Closes Na+ channels and returns to RMP
Repolarization
Review: Opens K+ channels
Hyper polarization
Depolarization and hyperpolarization
contribute to nervous system function via…
Graded potentials
Localized(stays within 1 neutron) changes in membrane potential
Graded potentials
Helps cell body decide whether to pass incoming dendrite signals
Graded potentials
TF: GP can depress and exhibit a neuron
False
Excite
Inhibit
In Excitatory postsynaptic potential (EPSP), Na channels open =
Na influx & Depolarization
In Inhibitory postsynaptic potential (IPSP)
• K+ channels open
K+ efflux & Hyperpolarization
What will lead to an action potential
A strong EPSP
Rapid depolarization
Reach threshold mV
If GP reaches … … (threshold mV), AP will occur
-55mV to -50mV
Keeps total of EPSP and IPSP
Axon hillock
2 characteristics to determine AP propagation speed
Axon diameter: larger=faster
Myelin
Site of neuron to neuron communication in AP transfer
Synapse
Explain how an action potential is transmitted from a presynaptic neuron
to a postsynaptic neuron
Presynaptic axon terminal -> SYNAPSE -> postsynaptic dendrites
What are the signal changes across synapse
Electrical - chemical - Electrical
– Chemical messengers
– Carry electrical AP signal across synaptic clef
Neurotransmitters
Site of neuron-to-muscle communication using ACh as a neurotransmitter
Neuromuscular junction
NJ: ACh binds to receptor at what site
Motor end plate
NJ: Postsynaptic cell=
Muscle fiber
4 regions of the Brain
– Cerebrum
– Diencephalon
– Cerebellum
– Brain stem
Region of the brain where decisions are made about controlling movement
Frontal lobe
Lobes of the brain
Frontal
Temporal
Parietal
Occipital
What does thalamus in cerebrum/temporal lobe do?
– Regulates what sensory input reaches conscious brain
– Determines what we are consciously aware of.
What does hypothalamus in cerebrum/temporal lobe do?
Maintains homeostasis
What does cerebellum do?
Controls rapid, complex movements
• Coordinates timing, sequence of movements
• Compares actual to intended movements and initiates correction
• Accounts for body position, muscle status.
• Receives input from primary motor cortex; helps
execute and refine movements
What does brain stem do?
Relays information (both ways) between brain and
spinal cord
– Coordinates skeletal muscle function and tone
– Controls cardiovascular and respiratory function
Reticular formation
Composed of tracts of
nerve fibers that permit two-way conduction of nerve impulses
Connects CNS to PNS
Spinal cord
PNS: Connects to brain from what 43 pairs of nerves
– 12 pairs of cranial nerves (originate from brain)
– 31 pairs of spinal nerves (originate from spinal cord)
– Both types directly supply skeletal muscles
PNS:Transmits information from periphery to brain
Sensory (Afferent) Division
Transmits information
from brain to periphery
Motor (Efferent) division
ANS Division with Fight or flight: Prepares body for exercise
Sympathetic nervous system
ANS division with Rest and Digest
Parasympathetic nervous system
Fastest mode of response
Motor reflex
How does reflex movement occur when touching hot object
Motor reflex being preprogrammed response before conscious awareness
Muscle spindles role in controlling muscle contractions
When stretched, it triggers reflex muscle contraction
Golgi tendon role in muscle contraction
Reduces injury in resistance exercise
Inhibits agonist muscle
Sensitive to tendon tension
Major Sensory receptors functions (Mechanoreceptor, Thermo, Noci, Photo, Chemo)
• M: pressure, touch,
vibrations, stretch
• T: temperature
• N: pain
• P: light (allows for vision)
• C: odors, O2, CO2, glucose, electrolytes
3 special nerve endings
-Joint kinesthetic receptors
-Muscle spindles
-Golgi tendon organs
Special nerve ending sensitive to
-joint angles and rate of change
-muscle length, rate of length
-tension applied by tendon
Joint kinesthetic receptors
Muscle spindles
Gogi tendon organs
Two divisions of Motor efferent division
– Autonomic: regulates
visceral activity
– Somatic: stimulates
skeletal muscle activity
Sensory reception imbedded in tendon
Golgi tendon organs
