Ch. 11 and 12 quiz

first event occurring at chemical synapse

Action potentials arriving at the presynaptic terminal cause voltage-gated Ca²⁺ channels to open.

second event occurring at chemical synapse

Ca²⁺ diffuses into the cell and causes synaptic vesicles to undergo exocytosis, releasing neurotransmitter molecules.

fourth event occurring at chemical synapse

Neurotransmitter molecules bind their receptor sites, causing ligand-gated Na+ channels to open. Na+ diffuses into the cell or out of the cell, causing a change in membrane potential.

third event occurring at chemical synapse

Neurotransmitter molecules diffuse from the presynaptic terminal across the synaptic cleft.

form myelin sheath in PNS

Schwann cells

multi-functioning cells involved with neurogenesis, scar formation, BBB maintenance

astrocytes

The motor division is divided further into a somatic motor division _______ motor division

autonomic

brachial plexus nerves

axillary, musculocutaneous, median, ulnar, radial

When a doctor gives a patient epidural anesthesia, they are inserting a needle between which two structures?

body of vertebra (bone) and dura mater

central nervous system includes

brain and spinal cord

The nervous system is divided into the_______ nervous system, which includes the brain and spinal cord, and the ________ nervous system, which includes cranial nerves, spinal nerves, and ganglia

central, brain , peripheral

higher concentration outside the cell

chloride ions and sodium

coccygeal plexus nerves

coccygeal nerve

peripheral nervous system includes

cranial nerves, spinal nerves, ganglia

Endoneurium

delicate layer of connective tissue surrounding a single axon and its schwann cell sheath

As these ions enter the cell, the cell membrane undergoes ________________, with the membrane potential increasing to a peak of approximately +30mV.

depolarization

sensory neurons conduct action potentials through the _______ _____ of spinal cord

dorsal root

what structure makes dorsal root different from the ventral root

dorsal root has ganglion

function in the production and circulation of CSF

ependymal cells

During the absolute refractory period, a stimulus of high intensity may trigger a nerve impulse. true or false

false

cervical nerves control

head movement, diaphragm movement, neck and shoulder movement, upper limb movement

sacral and coccygeal nerves are located

hip bone (sacral) and at end of spinal cord

The membrane potential actually dips lower than -70mV because the potassium channels do not close quickly enough. This phase is called

hyperpolarization.

Golgi tendon reflexes provide

involve interneuron, prevent excessive damage to tendon, promote muscle relaxation

Perineurium

layer of connective tissue surrounding a nerve fascicles

Epineurium

layer of dense connective tissue surrounding a nerve

lumbar nerves control

lower limb movement and hip

Macrophages of the CNS

microglia

The peripheral nervous system is further subdivided into an afferent (sensory) division and an efferent (.___________ ) division.

motor

ventral roots contain

motor axons

___________ conduct action potentials from the spinal cord to an effector organ

motor neuron

Lumbosacral plexus nerves

obturator nerve, femoral nerve, sciatic nerve

form myelin sheaths in the CNS

oligodendrocytes

The afferent or sensory division transmits impulses from __________________

peripheral organs to the CNS.

cervical plexus nerves

phrenic nerve

interneurons are used in ____________ reflex arcs

polysynaptic

higher concentration inside the cell

potassium and negatively charged proteins

For a typical neuron, what limits the maximal frequency attainable of action potentials moving down an axon?

refractory period

As cations leave the cell, the membrane potential at that part of the membrane once again becomes negative. This phase of the action potential is called__________because the resting membrane potential is being reestablished.

repolarization,

thoracic nerves control

rib movement in breathing, vertebral column movement, hip mpvement

support cells in PNS that surround neuronal cell bodies

satellite cells

doral roots contain

sensory axons

__________ conduct action potentials from the stimulus site to spinal cord

sensory neurons

a stimulus is detected by

sensory receptor

reflex arc pathway

sensory receptor, sensory neuron, interneuron, motor neuron, effector

somatic motor division serves

skeletal muscle

autonomic motor division serves

smooth muscle, cardiac muscle, glands

__________ summation occurs when multiple action potentials arrive simultaneously at two different presynaptic terminals that synapse with the same postsynaptic neuron cell body.

spatial

The efferent or motor division transmits impulses from _____________________

the CNS out to the peripheral organs

An action potential will not occur unless the membrane potential at the __________ (the initial segment of the axon) reaches a level called _________

trigger zone, threshold.

motor neurons conduct action potentials through the _____ _____ of spinal cord

ventral root

As the peak of the action potential is reached, the sodium channels close and the ____________open, allowing these ions to diffuse out of the cell.

voltage-gated potassium channels

When threshold is reached, _________of the initial segment open briefly, allowing ________to diffuse into the cell.

voltage-gated sodium channels, sodium