week 4 and 5 review Flashcards
Neuron
generates electric signal and delivers it to other cells
Neuroglia
support cells
Neurofibrils
bundles of neurofilaments that provide support for dendrites and axon
Neural Tissue
Connective tissue and it’s avascular
Neurons in the CNS
anaxonic neurons, multipolar neurons (common)
Neurons in the PNS
Bipolar and Unipolar neurons (uncommon)
Typical Neurons
have cell body, contains 2 or more long fibers, impulses are carried along one or more of these fibers, called dendrites, to the cell body.
Sensory Neurons
Afferent neurons of PNS: taking the signal to the brain
Ganglion
a cluster of cell bodies
Myelination
the process of coating the axon of each neuron with myelin, which protects the neuron and helps it conduct signals in the nervous system without its axons becoming less efficient
Demyelination
reduces the rate at which axons transmit signal, resulting in a comprised immune system
Where is K+ greater in a neuron?
inside the cell
Where is Na+ greater in?
Outside the cell
Which components of the cell membrane control permeability
sodium potassium exchange pumpe
Passive channels
leak channels
Active channels
open and close response to stimuli
What would happen if a cell was completely permeable?
There would be an overflow of sodium causing an imbalance within the cell
T/F the electrical gradient can oppose the chemical gradient
True, ex: the net electrochemical gradient tends to force potassium ions out of the cell
What is the electrochemical gradient
The gradient of the electrochemical potential, the electrical potential and a difference in the chemical concentration across a membrane
What is a resting membrane potential
-70Mv, more sodium outside the neuron than potassium inside the neuron, present in neurons
What maintains the resting membrane potential
ATP
What is the value for a typical neuron?
-70Mv
What is the function of the Na+/K+ pump
balances passive forces of diffusion, ATP required.
Chemically gated
open or close when specific chemicals, found on neuron cell body and dendrites
Voltage gated
respond to changes in membrane potential, activation gates (open), inactivation gates (close), found in neurons (axons), skeletal and cardiac muscle
Depolarization
membrane potential rises due to opening of sodium channel making an increase in sodium (moving from negative to less negative value)
Repolarization
back to normal, when the stimulus is removed, membrane potential returns to normal
Hyperpolarization
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 (negative to more negative)
What is meant by graded potential?
change in membrane potential at site of stimulation; effect decreases with distance.
An Action potential?
Propagated changes in membrane potential, affect an entire excitable membrane
All or Nothing
meaning action potential is either triggered by the given stimulus (threshold reached) or not (threshold not reached)
Pre synaptic cell
Arch stored in vesicles at axon terminal
Neurotransmitter
A chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse, and by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve structure
Where are neurotransmitters synthesized
cholinergic sysnapses
What triggers release of neurotransmitters such as ACh
voltage gated arrival of action potential
T/F The anterior median fissure and Posterior mediam sulcus divide across section of the spinal cord into dorsal and ventral halves
True
Afferent Neurons
receive sensory and sends a signal to body for a response
Efferent Neurons
Receives motor signal to send to body
Where are the enlargements of the spinal cord located
Cervical and Lumbar, increased by grey matter
Two structures combined to form the coccygeal ligament… what are they
conus medullaris filum terminale
Dorsal roots
contains axons of sensory neurons to the spinal cord
Ventral roots
contains axons of motor neurons to somatic and visceral effectors
Dorsal Root Ganglion
contain cell bodies of sensory neurons
What is the cauda equine
last nerves coming out of spinal cord
Spinal Meninges
Dura Mater (outer layer), Arachnoid Mater (mid layer), Pia Mater (Inner layer) of neurons
Meningeal spaces
Epidural space (between dura mater and vertebral canal subdural space, Potential Space filled with CSF
Difference between epidural block and spinal tap?
Epidural is a catheter left in your back, the spinal tap is a onetime shot
Where is CSF
passageway of spinal cord and brain
How is the spinal cord stabilized longitudinally? Laterally?
Foramen Magnum.
Laterally: denticulate ligaments
Difference between grey and white matter
grey surrounds central canal, white matter is superficial
How do sensory nuclei differ from motor nuclei
Sensory: posterior, receive and relay info from peripheral receptors
Motor: anterior, send motor commands to peripheral effectors
T/F a frontal section through the central canal of the spinal cord divides across section of the spinal cord into doral and ventral halves
Tru
Gray and white commisssures
axons cross from one side of spinal cord to toher
Differences between funiculi and fasciculi
Funiculi: columns
Fasciculi: Tracts
What is the difference between a nerve and a tract
A tract is a collection nerve fibers in the CNS, a nerve is a collection of nerve fibers in the PNS.
Epineurium layer (peripheral nerves)
outer layer, dense network of collagen fibers
Perineurium layer (peripheral nerves)
middle layer, divides nerve into fascicles (axon bundles)
Endoneurium layer (peripheral nerves)
inner layer, surrounds individual axon
Spinal nerve
Distribution of motor commands
Peripheral nerve
Delivery of sensory information
Nerve Plexus
Spinal nerves controlling skeletal muscle in neck
Major nerve in cervical plexus and its function
Phrenic Nerve, controls diaphragm
Interneurons
a neuron that transmits impulses between other neurons
Two divisions of the Autonomic Nervous system (ANS)
Sympathetic (fight or flight) and Parasympathetic
Somatic Nervous system vs ANS
SNS is voluntary and ANS is involuntary
White ramus
Myelianted preganglionic fibers to sympathetic hain ganglion
Gray Ramus
to spinal cord.
Terminal Ganglion
near organ
Intramural Ganglion
embedded in Organ
Splanchnic nerves
consists of axons that synapse in collateral ganglia
