unit 2 chapters 12,13,14 book anatomy

endocrine system

communicates by means of chemical messengers (hormones)secreted in the blood

nervous system

employs chemical (neurotransmitters) and electrical means to send messages from cell to cell.

sensory input

monitor internal and external stimuli.

integration

brain and spinal cord process sensory input and initiate responses

homeostasis

regulate and coordinate physiology

mental activity

conciousness, thinking, memory emotion

functions of nervous system

sensory input, integration, controls muscles and glands, homeostasis, mental activity.

name the outer covering indicated by the arrow labeled A

myelin sheath

All characteristics of neuroglia

They protect the neurons and help them function, They bind neurons together and provide supportive scaffold

maintaining internal coordination

function of both endocrine and nervous system

excitability, conductivity, secretion

fundamental physiological properties of neurons

Astrocytes, microglia, ependymal cells, oligodendrocytes

Types of glial cells are found in the central nervous sytem

neurons classes

Sensory, inter, and motor, are the three classes of

Dendrites

The soma of a neuron gives rise to branch-like processes called what? They are the primary sites for receiving signals from other neurons.

Neuroglia

Which cells protect the neurons and help them function?

endocrine, nervous

Two organ systems are dedicated to internal coordination, communication between the other systems, and maintaining the overall homeostasis of the body. They are the ___system, which communicates by means of hormones, and the___system which sends quick electrical and chemical messages from cell to cell.

insulation

The myelin sheath is a spiral layer of___around a nerve fiber

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 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

interneurons, sensory neurons, motor neurons

three functional classes of neurons

1:1

approximate ratio of glial cells to neurons

unmyelinated

An axon lacking a myelin sheath is said to be

Signal conduction will be faster

Which is true about a neuron with a large diameter, myelinated axon as compared to a neuron with a small diameter, unmyelinated axon?

lipids and protein

The myelin sheath is composed mostly of which of the folowing

in both the central and peripheral nervous systems

Where are unmyelinated axons found?

Large unmyelinated axon

Which of the following would have the fastest conduction speed?

Potential Energy

An electrical potential is a form of what type of energy?

True

Unmyelinated nerve fibers (axons) in the PNS are enveloped in Schwann cells.

True false question.

Potassium

The plasma membranes is most permeable to which of the following ions?

Endoneurium

Which of the following is required for nerve fiber regeneration?

Local potentials

Which term refers to decremental changes in electrical potential along a dendrite or the soma?

A form of potential energy that can produce current

Which best describes an electrical potential?

K⁺ is more concentrated in the ICF than in the ECF.

Which of the following contributes to the development of the resting membrane potential in neurons?

Presence of myelin, diameter of axon

All the factors that influence the speed of nerve signal conduction

grade, decremental

characterstics of local potentials

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

absolute

The refractory period in which no stimulus of any strength will trigger a new action potential is the______ refractory period.

Threshold

The minimum amount of voltage needed to open voltage-gated channels on an axon is called what?

refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus?

refractory period

presynaptic

At a synapse, the neuron that releases neurotransmitter is the ______ neuron.

• Unmyelinated fibers have voltage-gated channels along their entire length.

• A zone of depolarization excites voltage-gated channels immediately distal to the action potential.

Choose all of the following statements that are true about signal conduction along unmyelinated fibers.

A wave of depolarization opens more voltage-gated channels immediately distal to the action potential.

Which best describes signal conduction in unmyelinated axons?

Gap junctions

In electrical synapses, electrical signals move quickly from cell to cell through which of the following?

relative

The refractory period in which it is possible to trigger a new action potential, but only with an unusually strong stimulus is the ______ refractory period.

postsynaptic

The neuron that responds to the presynaptc neuron is called the

Postsynaptic neuron

In a chemical synapse, synaptic vesicles full of neurotransmitter are docked at release sites on the membrane of the presynaptic neuron, while neurotransmitter receptors are found on the membrane of the____ _____

Neurotransmitter is removed from synaptic receptors

Stimulation of the postsynaptic neuron will end when nerve signals stop arriving at the presynaptic axon terminal or when which of the following occurs?

synaptic cleft

Which term refers to the microscopic physical gap between the presynaptic and postsynaptic neurons at a chemical synapse?

Postsynaptic potentials

ESPSs and IPSPs are examples of

The type of receptors on the postsynaptic cell

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

Choose all that would cause postsynaptic stimulation to end.

• Reuptake of neurotransmitter into the presynaptic knob

• Diffusion of neurotransmitter from the synaptic cleft into extracellular fluid

• Cessation of signals in the presynaptic nerve fiber

• Enzymatic degradation of neurotransmitter in the synaptic cleft

In the axon terminal

In a synapse, where are synaptic vesicles located?

Chemical synapses

Which are the sites of learning and memory?

-70 mV

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

All statements that are true regarding postsynaptic potentials?

• They include EPSPs and IPSPs.

• They are changes in the membrane potential of the postsynaptic terminal of a chemical synapse.

• They are caused by neurotransmitters

• They are inhibitory.

• Their actions depend on their receptors.

• They are excitatory.

All that are true of neurotransmitters

EPSPs

Sodium ions flowing into a neuron cell membrane are most likely to produce what?

-55

Which is most likely to be the threshold potential for neuron

Postsynaptic potentials

Neural integration is based on the combining together of which of the following?

All of the following that may be the result from inhibitory postsynaptic potentials

• Opening Cl^- channels

• Opening K⁺ channels

Sodium

Excitatory postsynaptic potentials (EPSPs) are usually due to the entry of which type of ion?

Chloride or potassium

Inhibitory postsynaptic potentials is usually is usually due to to the opening of which type of ion channels?

When sodium channels open

When do EPSPs usually occur?

Which neurotransmitters are excitatory to some cells and inhibitory to others, depending on the type of receptors on the target cells?

• Acetylcholine

• Norepinephrine

oligodendrocytes

myelin sheaths are created by___in the central nervous system

axon

___is the cellular process that carries the impulse away from the neuron cell body

neurons, glial

Two cell types of nervous tissue are the__,and___

schwann cells

myelin sheaths are created by___in the peripheral nervous system

dendrites

___are the cellular processes of the neuron that receive the input

axon to dendrite

In which direction does the neurotransmitter cross a synapse?

On the axon

Where is the synaptic knob located?

multiple dendrites and one axon

multipolar neurons have

sensory or afferent neurons

Unipolar neurons generally function as

soma

The cell body is also known as the

axon neuron

Which part of a neuron carries the impulse away from the cell body?

microglia

Derived from white blood cells, these cells in the central nervous system are often found at the site of injury of brain tissue.

ependymal cells

Which type of neuroglial cells produces cerebrospinal fluid?

Schwann cells form a myelin sheath around a portion of only one axon, while oligodendrocytes can surround portions of several axons.

Schwann cells differ from oligodendrocytes in which of the following ways?

sodium ion

What ion is found on the outside of the neuron membrane that is a major contributor to the resting membrane potential?

after repolarization

potassium ion channels close

repolarization of the neuron

Opening of potassium ion channels typically leads to

sodium-potassium pump and leaky potassium ion channels

What maintains the resting membrane potential of a neuron?

resting membrane potential

The sodium/potassium pump is primarily responsible for the

All that are functions of spinal cord

Locomotion, conduction, reflexes

foramen magnum

What structure marks the superior end of the spinal cord?

Anterior median fissure

A longitudinal groove on the ventral surface of the spinal cord is which fissure

cervical, thoracic, lumbar, sacral

all regions of the spinal cord

For the level of vertebral column from which its spinal nerves emerge.

How are the spinal cord regions named?

medullary cone

The foramen magnum

Where does the spinal cord arise from the medulla oblongata?

The longitudinal groove on the dorsal surface of the spinal cord

What is the posterior median sulcus of the spinal cord?

cauda equina nerve bundles

The bundle of nerves inferior to the medullary cone of the spinal cord is called the ____ ____

meninges

Which are a series of fibrous connective tissue membranes covering the central nervous system?

posterior

The____ median sulcus is a longitudinal groove on the dorsal surface of the spinal cord.

Dura

The dural sheath around the spinal cord is formed from the____mater

A bundle of nerve roots occupying the vertebral canal from L2 to S5

What is the cauda equina?

epidural

the____space is located between the vertebrae and the dural sheath around the spinal cord.