Chapter 12. Nervous Tissue

the visceral motor division of the PNS is also called the autonomic division. which of the following are functions of this division? select all that apply

- Controlling gland secretion - Accelerating or decreasing heartbeat - Stimulating or inhibiting digestion.

which term refers to the voltage difference (electrical potential) across the plasma membrane of a neuron when it is at rest and not engaged in electrical signaling?

resting membrane potential

the motor division of the PNS is further subdivided into the ________ motor division that carries signals to the skeletal muscles and the _______ motor division (also known as the autonomic nervous system), which carries signals to glands, cardiac muscle, and smooth muscle

somatic visceral

the sensory and motor divisions of the peripheral nervous system are further split into which two subdivisions?

somatic and visceral

there are two ways in which EPSPs can add up to produce enough activity to make a postsynaptic cell fire: temporal and spatial _________________.

summation

which best describes an electrical current?

the movement of charged particles like ions

Some neurotransmitters can be either excitatory or inhibitory effects depending on which of the following?

the type of receptors on the postsynaptic cell

an axon lacking a myelin sheath is said to be...

unmyelinated

which type of memory allows us to hold a thought long enough to take action on it?

working

categorize the six kinds of neuroglia according to whether they are found in the CNS or in the PNS

• CNS = ependymal cells, microglia, astrocytes, oligodendrocytes • PNS = Schwann cells, satellite cells

neurons are classified structurally according to the number of processes extending from the soma. match each classification to its description.

• multipolar neurons = one axon; multiple dendrites • bipolar neurons = one axon; one dendrite • unipolar neurons = a single process • anaxonic neurons = no axon; multiple dendrites

place these events into the order in which they occur during a single action potential

Local potential depolarizes membrane Threshold is reached Depolarization spike Repolarization Hyperpolarization

this is the most common structural type of neuron. it contains one axon and multiple dendrites, and it is classified as a(n) ______ neuron

Multipolar

which best describes an electrical potential?

a form of potential energy that can produce current

which statements are true regarding postsynaptic potentials? select all that apply.

a) they are changes in the membrane potential of the postsynaptic terminal of a chemical synapse b) they are caused by neurotransmitters c) they include EPSPs and IPSPs

match each point in the action potential to the corresponding description of voltage-gated sodium and potassium channel activity

resting membrane potential = both types of voltage-gated channels are closed depolarization begins = voltage-gated Na+ channels open; voltage-gated K+ channels open more slowly repolarization begins = voltage-gated Na+ channels inactivate; voltage-gated K+ channels remain open longer

motor, or ______________, neurons carry signals away from the CNS and they lead to effectors (muscle and gland cells).

efferent

which two organ systems are primarily responsible for coordinating the other bodily systems so as to maintain homeostasis? select two answers from the list below.

endocrine system nervous system

the Schwann cell coils around the nerve fiber, finally ending with a thick outermost coil called neurilemma. external to the neurilemma there is a thin sleeve of fibrous connective tissue called the _______

endoneurium

which term is used to describe signal conduction along a myelinated axon?

saltatory

A shift in membrane voltage to a value that is more negative than the resting membrane potential is called

hyperpolarization

the opposite of facilitation is presynaptic _______. this is mechanism in which one presynaptic neuron suppresses another one

inhibition

Which types of glial cells are found in the central nervous system?

oligodendrocytes, astrocytes, ependymal cells, and microglia

the brain and spinal cord are components of the ________ nervous system, while the nerves and ganglia are components of the ________ nervous system

peripheral central

which ion has the greatest influence on the resting membrane potential of most neurons?

potassium

at a synapse, the neuron that releases neurotransmitter is the _________________ neuron.

presynaptic

which correctly describe axonal transport? select all that apply

- It is bidirectional (retrograde and anterograde transport) - It involves transport of proteins within the axon (i.e. synaptic know enzymes or proteins that maintain the axolemma).

this picture illustrates signal conduction along unmyelinated fibers. indicate which of the following statements are true about this type of conduction. select all that apply

- a zone of depolarization excites voltage-gated channels immediately distal to the action potential - unmyelinated fibers have voltage-gated channels along their entire length

which are characteristics of local potentials? select all that apply

- decremental - graded

list the three functional classes of neurons. select all that apply

- sensory neurons - interneurons - motor neurons

list characteristics of neuroglia

- they Protect the Neurons and help them function - They bind neurons together and provide a supportive scaffold.

which statements are true about Schwann cells? select all that apply

- they form the myelin sheath in the PNS - they assist in the regeneration of damaged nerve fibers - they form the neurilemma

which numerical value is most likely to be the resting membrane potential of a neuron

-70 mV

which numerical value is most likely to be the resting membrane potential of a neuron?

-70mV

which are the characteristics of neural pools? select all that apply

-They consist of complex patterns of intraneurons -They may be concerned with a particular body function

the nervous system plays an important role in maintaining homeostasis. list, in order, the basic steps that describe how the nervous system carries out this task

1. Info received by sensory receptors is transmitted to the CNS 2. Info is processed and an appropriate response is determined 3. A command is issued to effectors such as muscles or glands

list in chronological order the stages of regeneration of a nerve fiber

1. degeneration of axon and myelin distal to injury 2. swelling of soma; dispersal of Nissl bodies 3. sprouting of axon growth processes 4. growth process enters regeneration tube 5. reestablishment of synaptic contact

starting with a signal reaching the distal end of the presynaptic axon, indicate the correct order of events that occur during transmission at a cholinergic excitatory synapse

1. opening of calcium gates in synaptic knob as nerve signal arrives 2. exocytosis of ACh; diffusion across synaptic cleft 3. binding of ACh to receptors on postsynaptic neuron 4. opening of sodium gates on post-synaptic membrane allowing influx of sodium 5. depolarization of postsynaptic plasma membrane

match each glial cell type with its location and function

Satellite cells = in the PNS; surround somas of neurons in ganglia, provide electrical insulation, and regulate the chemical environment of neurons Schwann cells = in the PNS; form neurilemma around all PNS fibers and myelin around most of them; aid in the regeneration of damaged nerve fibers Ependymal cells = in the CNS; line cavities of the brain and spinal cord; secrete and circulate CSF Microglia = in the CNS; phagocytize microorganisms, foreign matter, and dead nervous tissue

match the neuropeptide with its corresponding location and action

Substance P = Brain, small intestine, and pain-receptor neurons; Mediates pain transmission Enkephalins = Various areas of the brain, spinal cord; Act as analgesics by inhibiting Substance P, secretion increases during labor B-endorphin = Digestive tract, spinal cord, and many parts of the brain; Secreted as a hormone by the pituitary; suppresses pain, reduces fatigue, may produce "runner's high." Cholecystokinin (CCK) = Cerebral cortex, small intestine; Suppresses appetite.

the autonomic nervous system is subdivided into the ________ division which tends to arouse the body for action and the _______ division which tends to have a calming effect

Sympathetic Parasympathetic

Name the long neuronal process that generally conducts impulses away from the soma of the nerve cell.

axon

match the following terms with their description

axon hillock = a mound located on one side of the soma from which the axon originates axoplasm = cytoplasm of the axon axolemma = plasma membrane of the axon axon collateral = branch that originates from an axon

Since neurons generally do not undergo mitosis after reaching maturity, which organelle do they lack?

centrioles

what creates electrical currents in neurons?

movement of ions through channels

this picture illustrates that when a stimulus strength (weight) and stretch increase at a sensory fiber, the firing frequency of the neurons increase. which term refers to the conversion of stimulus information into a meaning pattern of action potentials?

neural coding