Lab Exercise 16 Flashcards
What do neurons do?
conduct action potentials, electrical signals, that are generated in response to a strong stimulus
What do neuroglial cells do?
support, protect, furnish nutrients to neurons, augment the speed of action potentials
What four neuroglial cells are in the CNS?
astrocytes, oligodendrocytes, microglia, ependymal cells
What do astrocytes do?
guide neurons during development and control the composition of the chemical environment of the neurons by forming a blood-brain barrier that only allows certain substances to enter the nervous tissue at the blood vessel sites
What do oligodendrocytes do?
support the CNS and have processes that form the myelin sheaths around axons to increase the speed of nerve impulses
What do microglia do?
the phagocytes of the CNS that engulf debris, necrotic tissue, and invading bacteria or viruses
What do ependymal cells do?
line all 4 ventricles of the brain, as well as the central canal of the spinal cord, form cerebrospinal fluid and their cilia move the CSF through the ventricles
What do neuroglial cells are in the PNS?
Schwann cells and satellite cells
What do Schwann cells do?
wrap around the axons in the PNS, form myelin sheaths around one axon
What do myelin sheaths do?
increase nerve impulse speed and aid in the regeneration of PNS axons
What do satellite cells do?
surround sensory neuron cell bodies located in ganglia in the PNS and give support to these neurons and regulate their chemical environment
What do dendrites do?
receive information and convert it to a change in membrane potential called a graded potential that travels to the neuron cell body/soma
What is an axon hillock?
a triangular or cone-shaped area of the cell body
What is the trigger area?
the first part of the axon where the action potential begins
What are axon collaterals?
side branches off of an axon
What are axon terminals?
axons and axon collaterals conduct action potentials along their full lengths to end in many fine branches called axon terminals, many axon terminals end in synaptic end bulbs which contain neurotransmitter molecules that transmit signals across a synapse
What are multipolar neurons?
neurons that have several dendrites and one axon
What are bipolar neurons?
have one dendrite and one axon on either side of the cell body
What are unipolar neurons?
have only one process leading to and from the neuron cell body formed by the fusion of the dendrites and the axon
What are the functional classifications of neurons?
sensory (afferent), interneuron (association), motor (efferent)
What are sensory neurons?
if there is strong enough stimuli to the receptors associated with the dendrites of sensory neurons, it will generate an action potential or nervous impulse that travels along the axon to the spinal cord; most sensory neurons are unipolar; in the spinal cord, the axon of the sensory neuron synapses with either a motor neuron or an interneuron
What are interneurons?
multipolar neurons that make up 90% of the neurons in the CNS; in the spinal cord, the interneuron can synapse with a chain of interneurons that sends the signal to the brain, and/or it can synapse with a motor neuron
What do motor neurons do?
takes the impulse out of the CNS via a spinal or cranial nerve to an effector (muscle or gland); multipolar neurons
How does the neurolemma form?
multiple layers of the plasma membrane surround the axon, and the cytoplasm and nucleus are pushed to the periphery
What do myelin sheath gaps do?
allow the nerve impulse to jump from node to node
What is white matter?
groups of myelinated axons in the CNS, inner area of white matter in the brain, outer layer of white matter in the spinal cord
What is gray matter?
unmyelinated areas comprised of neuron cell bodies, dendrites, axon terminals, and neuroglia; outer area or cortex in brain, inner H shaped shaped in spinal cord
What do presynaptic neurons do?
action potentials in the presynaptic neuron causes the release of neurotransmitter into the synaptic cleft
What do postsynaptic neurons do/
has receptors that bind the neurotransmitter and in response generates a graded potential called a postsynaptic potential
What is an axo-axonic synapse?
axon to axon
What is an axodendritic synapse?
axon to dendrite
What is an axosomatic synapse?
axon to the cell body
