Neural tissue WS- Ch. 13

Ependymal cells

-Neuroglia in CNS -Line ventricles (brain) and central canal (spinal cord) -Assist in producing, circulating, and monitoring CSF (LIKE A PEN LINES INK CARTRIDGE+ PRODUCES INK)

Astrocytes

-Neuroglia in CNS -Maintain blood-brain barrier (avoid ASTROIDS hitting it) -Provide structural support -Regulate ion, nutrient, and dissolved-gas concentrations -Absorb and recycle neurotransmitters -form scar tissue after injury

Microglia

-Neuroglia in CNS -Remove cell debris, wastes, and pathogens by phagocytosis

Schwann cells

-Neuroglia in PNS -Surround all axons in PNS -Myelinate peripheral axons -participate in repair process after injury

Satellite cells

-Neuroglia in PNS -Surround neuron cell bodies in ganglia -regulate O2, CO2, nutrient, and neurotransmitter levels around neurons in ganglia

What are the types of synapses?

-axodendritic (dendrite is postsynaptic) -axosomatic (cell body is postsynaptic) -axoaxonic (axon is postsynaptic) -neuroeffector junctions ( b/w neuron and other cell type, ex: neuromuscular synapse)

Bipolar neurons

-have a number of fine dendrites that fuse to form a single dendrite -cell body lies b/w this dendrite and a single axon -are relatively rare but play important role in relaying sensory information concerning sight, smell, and hearing -unmyelinated axons

Pseudounipolar neurons

-have continuous dendritic and axonal processes, and cell body lies off to one side -initial segment lies at base of dendritic branches, and rest of process is structurally and functionally considered an axon -sensory neurons of the PNS are usually pseudo unipolar -axons may be myelinated

Multipolar neurons

-have several dendrites and a single axon that may have one or more branches -most common type of neuron in CNS -all motor neurons that control skeletal muscles are multipolar neurons with myelinated axons

Gray matter organization of CNS

-neural cortex -nuclei (collections of neuron cell bodies in the interior of the CNS) -centers (collections of neuron cell bodies in the CNS; each center has specific processing functions; higher centers are most complex centers in brain)

Functions of the peripheral nervous system include ______ -providing sensory information to the CNS only -making higher order decisions to interpret sensory inputs -carrying motor commands to the peripheral tissues and systems only -carrying information up and down the spinal cord -providing sensory information to the CNS and carrying motor commands to the peripheral tissues and systems

-providing sensory information to the CNS and carrying motor commands to the peripheral tissues and systems

Anaxonic neurons

-small, no anatomical clues to distinguish dendrites from axons -found only in the CNS and special sense organs -functions are poorly understood

White matter organization of CNS

-tracts (bundles of CNS axons that share a common origin and destination) -columns (several tracts that form an anatomically distinct mass)

What are the three functional groups of neurons

1. sensory neurons 2. motor neurons 3. interneurons

Over 50 different neurotransmitters have been identified, but the best known is _____

acetylcholine

The neuromuscular synapse is a vesicular synapse that releases the neurotransmitter ____

acetylcholine

Neuroglia in the nervous system function to ____ -carry nerve impulses -act as phagocytes -process information in the nervous system -transfer nerve impulses from the brain to the spinal cord -all of the above

act as phagocytes

The portion of a neuron that carries information in the form of a nerve impulse (action potential) is called the _____

axon

The area in a multipolar neuron that connects the cell body to the initial segment of the axon is called the ______

axon hillock

Movement of nutrients, waste products, and organelles between the cell body and the synaptic terminals is a process called ____

axoplasmic transport

The structural classification of a neuron is based upon ____

the number of processes that project from the cell body

Which of the following are examples of neuroeffector synapses? -neuromuscular synapse -neuroglandular synapse -neuroneural synapse -neuroaxonic synapses -both neuromuscular synapse and neuroglandular synapse

both neuromuscular synapse and neuroglandular synapse

The central nervous system (CNS) includes the ____

brain and spinal cord

The cell body usually has several branching ________, which are specialized to respond to specific stimuli in the extracellular environment.

dendrites

When sensory neurons bring information into the CNS that is subsequently distributed to neuronal pools throughout the spinal cord and brain, the type of processing is known as __

divergence

Which of the neuroglia produce cerebrospinal fluid?

ependymal cells (PEN)

Neuronal pools are defined on the basis of ___

function rather than on anatomical grounds

Satellite cells surround the cell bodies of peripheral neurons, which can be found in (the) _____

ganglia GANGS keep satellite of other gangs

In the PNS, the neuron cell bodies are found in clusters called _____

ganglia (gray matter)

If an axon ________, the impulse will be conducted ________.

has a larger diameter; more rapidly

Because a neuron loses its centrioles during differentiation, it ________. -is rendered incapable of dividing -cannot grow as quickly as neurons -loses its normal ability to produce a myelin sheath -is probably located in the PNS -all of the above

is rendered incapable of dividing

Pathways that connect the CNS with effectors include ______

motor pathways, descending pathways, efferent pathways

If the point of an extremely small probe were passed into a satellite cell, it would be located in which region of the nervous system?

near a cell body in a ganglion of the PNS

The nervous system includes all of the ________ tissue in the body.

neural

The surface of the brain is called the ______

neural cortex

Bundles of neurofilaments, called ________, are cytoskeletal elements that extend into the dendrites and the axon.

neurofibrils

The cells responsible for information processing and transfer are the ____

neurons

At a vesicular synapse, the neurons communicate via _____

neurotransmitters

Areas of a myelinated axon that are not covered by myelin are called _______

nodes of Ranvier

The type of synapse that allows the most direct communication between cells, and therefore the fastest communication, is the ________ synapse.

nonvesicular

Collections of neuron cell bodies in the interior of the CNS form larger groups called ____

nuclei

When a stimulus is applied to the axon, it produces a temporary change in the ________ of the axolemma in a localized area of the axon.

permeability

Axons connecting the ganglion cells with the peripheral effectors are called ________ fibers

postganglionic

The rate of conduction of a nerve impulse depends upon _____

properties of the axon. Wider, myelinated axons conduct impulses fastest

________ monitor the position and movement of skeletal muscles and joints.

proprioceptors

A type of information processing wherein information is relayed in a stepwise sequence, from one neuron to another or from one neuronal pool to the next, is called ______

serial processing

Microglia are (the) ____ -most numerous neuroglial cell -smallest neuroglial cell -not a neuroglial cell -least numerous neuroglial cell -none of the above

smallest neuroglial cell (MICRO)

Which of the following structures do NOT contribute to the coarse grainy appearance of the perikaryon of a neuron? -mitochondria -free and fixed ribosomes -rough endoplasmic reticulum -smooth endoplasmic reticulum -all of the above

smooth ER

Receptors may be classified as ____ -effectors and muscles -somatic and visceral -glands and muscles -voluntary and involuntary -subconscious and conscious

somatic and vsiceral

The efferent division of the PNS includes the ___

somatic nervous system, autonomic nervous system (visceral motor system)

Neurotransmitters are ________. -produced on command -stored in synaptic vesicles in the presynaptic membrane -never recycled -released only at electrical synapses -produced by astrocytes

stored in synaptic vesicles in the presynaptic membrane

To transmit a nerve impulse in vesicular synapses, the neurotransmitter diffuses across the ________ and binds to receptors on the postsynaptic membrane.

synaptic cleft

Injured neurons can fully recover their functional capabilities if _____

the oxygen and nutrient supplies are restored within a period of a few minutes

Involuntary cardiac muscle fibers of the heart are innervated by ________ fibers.

visceral motor

Areas of the nervous system that are dominated by myelinated axons are referred to as _____

white matter

Which of the following is the correct sequence of events at a synapse? 1. neurotransmitter release/diffusion 2. generation of action potential in the postsynaptic cell membrane 3. arrival of nerve impulse at terminal bouton in the presynaptic cell 4 removal of neurotransmitter molecules from receptors 5. binding of neurotransmitter to receptors

3,1,5,2,4

Glial cells are roughly ________ times the number of neurons.

5

Chromatophilic substance

AKA Nissl bodies -Groups of fixed and free ribosomes present in large numbers -Accounts for gray color of areas that contain neuron cell bodies, like the gray matter seen in gross dissection of the brain or spinal cord.

______ is the ability of a plasmalemma to respond to an adequate stimulus.

Excitability

All somatic neuromuscular synapses utilize ____

acetylcholine

white matter of PNS

Nerves (bundles of axons in the PNS)

During neural regeneration in the PNS as the neuron continues to recover, its axon grows into the injury site and the ________ wrap around it along its original path.

Schwann cells

Action potentials result from ____

a change in membrane potential of the axon

Nonvesicular synapses are unique because they have _____

a communicating junction

A neuronal pool is _____

a group of interconnected neurons with specific functions -defined on the basis of FUNCTION rather than anatomical grounds

Functions of the nervous system include which of the following? -seat of higher functions, such as intelligence, memory, learning, and emotions -receives sensory input; coordinates sensory input and motor output -regulates smooth muscle, cardiac muscle, and glandular activities -integrating and processing data -all of the above

all of the above

Interneurons ________. -are responsible for the analysis of sensory inputs and the coordination of motor outputs -are located entirely within the brain and spinal cord -can be classified as excitatory or inhibitory on the basis of their effects on the postsynaptic membranes of other neurons -outnumber all other neurons combined -all of the above

all of the above

To contact a Schwann cell, where would a microprobe have to be inserted in the nervous system?

along any axon in the PNS, myelinated or not

If the CNS were susceptible to a drug that should not affect it, this might indicate damage to which of the cells?

astrocytes

Cardiac muscle, smooth muscle, and glands are regulated by the _____ nervous system

autonomic

Cerebrospinal fluid is produced by ______

ependymal cells

The anatomical subdivisions of the nervous system are (the) ___

central and peripheral nervous systems

In electrical synapses, nerve impulse transmission occurs between cells of the CNS and PNS without any delay due to ____

communicating junctions that permit the passage of ions between the cells

Muscle cells, gland cells, and specialized cells that respond to neural stimuli are called _____

effectors

The ________ division of the PNS sends motor information to muscles and glands

efferent

Nonvesicular synapses, also termed ________, are found between neurons in both the CNS and the PNS.

electrical synapses

The nervous system and the ________ system share important structural and functional characteristics, such as relying upon some form of chemical communication with targeted tissues and organs.

endocrine

The effects of a neurotransmitter on the postsynaptic membrane include which of the following? -Excitatory or inhibitory responses result. -Neurotransmitter molecules are absorbed by the postsynaptic cell. -The neurotransmitter floats around in the synaptic cleft. -Upon stimulation, the membrane releases more neurotransmitter molecules. -none of the above

excitatory or inhibitory responses result.

The process of reverberation involves ________. -a negative feedback loop through nerve circuits -a single repeat of a stimulus prior to extinction -extension of collateral axons back toward the source of an impulse and further stimulation of the presynaptic neurons -several neuronal pools processing information at one time -all of the above

extension of collateral axons back toward the source of an impulse and further stimulation of the presynaptic neurons REVERANDS are POSITIVE (positive feedback)

Which of the following are most closely involved with somatic sensory neurons? -visceral sensory neurons -bipolar neurons -interoceptors -proprioceptors -exteroceptors

exteroceptors

When an action potential develops in one location of an axon, ________. -it will stimulate astrocytes to release chemicals -it will regenerate the threshold stimulus at the originating location on the same axon -Schwann cells in the area begin to divide and form a solid cellular cord -it will propagate along the length of the axon toward the terminal bouton -it will propagate faster along the smaller unmyelinated fibers

it will propagate along the length of the axon toward the terminal bouton

A neuron might be temporarily unable to transmit an impulse to another neuron or effector if ________. -its supply of neurotransmitters is exhausted -the neurons are of different types -the levels of microglia are too low -there are too many astrocytes present -the neurotransmitter is inhibitory

its supply of neurotransmitters is exhausted

An inhibitory response makes an action potential more or less likely?

less

In the process known as Wallerian degeneration ____

macrophages phagocytize the debris of damaged axons

A biopsy of infected or injured tissue from the CNS will most likely show an elevated number of _____

microglia

Which of the following selections lists only types of glial cells? -astrocytes and parenchymal cells -apocrine and exocrine cells -merocrine, platelet, and ependymal cells -microglia, oligodendrocytes, and Schwann cells -none of the above

microglia, oligodendrocytes, and Schwann cells

Myelin is (a) _____ -cell body in the peripheral nervous system -mostly lipid -special cell that forms scar tissue after injury -special area of the brain -none of the above

mostly lipid

Oligodendrocytes ________. -remove cell debris, wastes, and pathogens by phagocytosis -regulate oxygen, carbon dioxide, nutrient and neurotransmitter levels around neurons in ganglia -maintain the blood-brain barrier and provide structural support -provide structural framework and myelinate the central nervous system (CNS) axons -line the ventricles of the brain and the central canal of the spinal cord

provide structural framework and myelinate the central nervous system (CNS) axons

The functional classifications of neurons include ________, which carry information toward the CNS.

sensory neurons

A communicating junction acts to facilitate _______

the passage of ions between cells

In the case of somatic neuromuscular neurons, the arrival of a nerve impulse at the terminal bouton immediately triggers _____

the release of ACh at the presynaptic membrane

neurolemma

the superficial cytoplasmic covering of an axon provided by the Schwann cells

Collections of axons in the CNS that have a common origin and destination are called _____

tracts