Nervous Tissue Test and Flashcards

Describe the two ways the nervous system can be divided.

structurally, functionally

Describe the structural divisions of the nervous system.

Central nervous system (CNS): Brain, spinal cord Peripheral nervous system (PNS): cranial nerves, spinal nerves

Describe the functional division of the nervous system.

Automical nervous system (ANS): controlling centers within CNS Sympathetic: fight or flight parasympathetic: rest and digest

Sympathetic:

fight or flight

parasympathetic:

rest and digest

Neurology:

The study of the nervous system

What are the functions of the nervous system? (5)

-Orient the body to the internal and external environments -Coordinate body activities -Store experiences (memory) -Generate patterns of response based on experiences (learning) -Instinctual behavior (More important in vertebrates other than humans_

When does the neural plate form?

at 17 days

The neural plate gives rise to...

all neurons, most neuroglia

Plate invaginates forming neural ______ and neural folds

groove

nNeural crest forms from neural folds: (3)

qOriginates much of the PNSqForms sympathetic nervous systemqForms Schwann cells

What are the three distinct swellings after the fourth week of human development?

• Prosencephalon- • Mesencephalon-(remains unchanged to week 5) • Rhombencephalon-

What is the neuron responsible for?

Responsible for integrating information received from the internal and external environment

What is the neuron specialized for?

excitability and conductivity

Describe the 3 components of a neuron.

cell body, dendrites and axon

Describe the cell body of a neuron (3)

• Contains nucleus • Chromatophilic substance in Rough endoplasmic reticulum • Neurofilaments and microtubules

Describe axon of neuron

• Conducts impulses away from cell body • Neurofilaments and microtubules • Collateral branches

Describe the dendrite(s) of neurons

Branched processes; receive stimuli

The motor ( nervous system is responsible for transmitting motor impulses from the CNS TO effectors (muscles or glands). Is this efferent or afferent?

efferent (conducting outward)

The motor nervous system is responsible for input or output?

output

Motor neurons are typically what type of polar?

multipolar

Motor neurons are typically efferent meaning they carry impules ____ from CNS to target tissues.

AWAY

Most sensory neurons are...

unipolar

What sensory neurons are not unipolar?

Retina, olfactory epithelium (these are bipolar)

Interneurons are only found where and are what type of polar?

in the CNS, multipolar

What do interneurons do?

facilitate communication between motor and sensory neurons.

Describe sensory neurons

-afferent TOWARDS CNS (from body) -most unipolar

What are the two types of motor neurons?

somatic (non-visceral) autonomic (visceral)

Describe the function of somatic motor neurons.

Motor out that is consciously or voluntarily controlled; effector is skeletal muscle

Whats the effector in somatic motor function?

skeletal muscle

Describe autonomic motor function.

Motor output that is not consciously or is involuntarily controlled; effectors are cardiac muscle, smooth muscle, and glands

Effectors of autonomic motor neurons:

effectors are cardiac muscle, smooth muscle, and glands

Interneurons most notably dont have...

axons (anaxonic)

Cell body

Nucleus and surrounding cytoplasm of a neuron (excluding its dendrites and axon)

perikaryon

Most often refers to the cytoplasm within the cell body. Sometimes used to describe the entire cell body

Neurotubules

Microtubules that form the cytoskeleton

Neurofilaments

Intermediate filaments that aggregate to form bundles called neurofibrils

Dendrites

Neuron processes that conduct information to the cell body ("input")

Axon:

nerve fiber Neuron process that conducts nerve impulses away from the cell body ("output")

Axon hillock:

Triangular region connecting cell body to axon

Axon collaterals:

Side branches of an axon

Terminal arborizations:

Fine terminal branches of an axon or axon collateral

Synaptic knobs:

Slightly expanded regions at the tips of terminal arborizations

SAME DAVE:

(Sensory-Afferent, Motor-Efferent; Dorsal-Afferent, Ventral-Efferent).

Somatic motor reflex arc

• A receptor that senses the stimulus. • An afferent neuron that carries the signal to the CNS. • A center that decides how to respond. • An effector that performs the response.

What are the three structural classes of neurons?

-bipolar -pseudounipolar -multipolar

Describe the bipolar structural class of neurons.

• Spindle shaped • Process at both ends • Specialized sensory

Describe the pseudounipolar structural class of neurons.

• Single process that divides in two • Most sensory neurons • Cell body in ganglia

Describe the multipolar class of neurons.

• One axon, several dendrites • Motor neurons

What structural classification of neurons is most common?

multipolar

List the neuroglia that is part of the CNS. (4)

Astrocvtes Oligodendrocytes Microglia Ependymal cell

Function of astrocytes

Support, ionic buffering, blood-brain-barrier

Function of oligodendrocytes

Form myelin

Function of microglia

Phagocyte cellular debris

Function of Ependymal cell

Line ventricles, ciliated

List the neuroglia of PNS (peripheral nervous system).

Satellite cells (Ganglionic gliocyte) Schwann cell (Neurolemmocyte)

Which neuroglia contributes to the blood-brain barrier?

astrocyte

What is a glial cell?

Glial cells are small, mitotic cells that support and protect neurons in the nervous system and help them with their functions and development.

Is there more glial cells or neurons?

glial cells

Function of satellite cells (ganglionic gliocyte)

support (Protects and regulates nutrients for cell bodies in ganglia)

Function of schwann cells (neurolemmocyte)

Form myelin

One ______________ myelinates many neurons.

oligodendrocyte

What is myelin?

• Composed of lipid and protein Provides support Aids in conduction->FASTER

What the gap in the myelin sheath called?

Neurofibril node - gap in sheath

• Oligodendrocytes (CNS) form myelin sheath around _____ axons

many

Schwann cells (PNS) form sheath around ____ axon

ONE

Describe the myelination process in the PNS.

Schwann cell (PNS) wraps around axon Multiple layer (sheaths) are formed around ONE axon

Describe CNS myelination.

An oligodendrocyte in the CNS can myelinate a 1 millimeter length portion of MANY axons, not just one.

True or False: Myelin is fatty

True.

In the PNS, unmyelinated axons are still associated with...

neurolemmocyte

In the CNS, unmyelinated axons are or are not associated with oligodendrocytes.

are not

___________is an autoimmune disorder of the central nervous system, where there is progressive demyelination of neurons accompanied by the destruction of oligodendrocytes. This disrupts the conduction of nerve impulses, leading to impaired sensory perception and motor coordination

Multiple sclerosis (MS)

neurofibril nodes, or....

nodes of Ranvier.

Neurofibril nodes allow for a process called _______ conduction.

saltatory

What is the benefit of neurofibril node?

faster conduction

Unmyelinated axons have ________ conduction

continuous

Capillaries in brain___ ___ have pores between adjacent endothelial cells

DO NOT

Astrocytes have ______ processes

vascular

In the blood-brain barrier, Molecules must pass through both _________ cells and astrocytes This is known as: selectivity.

endothelial

Describe the structure of a nerve.(4)

• Collection of nerve fibers (axons) outside CNS •Each nerve fiber enclosed in connective tissue sheath - endoneurium •Group of fibers (fasciculus) surrounded by perineurium • Entire nerve surrounded by epineurium (•also encloses blood vessels)

Most nerves are composed of motor and sensory – _____ _____

mixed nerves

Some cranial nerves ____ motor or sensory

ONLY

Somatic skeletal:

Somatic skeletal

Describe the two functional properties of nerve impulses.

• Irritability: • Conductivity:

Irritability:

Dendrites and cell body responds to stimulus: Converts to an impulse

• Conductivity:

Transmission of impulse along axon or dendrite

Describe nerve impulses. (3)

• Exchange of sodium (Na+) and potassium (K+) ions across membrane along length of nerve fiber • Travels in one direction • All-or-none response

List the three components of synaptic transmission.

-synapse -presynaptic neuron -postsynaptic neuron

What is a synapse?

Functional connection between two neurons

What is a presynaptic neuron?

• Axon terminal contains synaptic vesicles

Postsynaptic neuron:

dendrite

In synaptic transmission, neurotransmitters are within ______.

vesicles

Neutrotransmitters are released into...

synaptic clef

Why is there a lot of mitochondria in the axon terminal?

A lot of mitochondria because of transport of ions

What are the ways a synapse can communicate?

-electrical synapse -chemical synapse

Chemical synapse use ____________.

neurotransmitters

In an ________ synapse, the plasma membranes of the presynaptic and postsynaptic cells are bound tightly together. Electrical synapses are fast and secure, and they permit two-way signaling. At this synapse, gap junctions formed by connexons between both plasma membranes ) facilitate the flow of ions, such as sodium ions (Na*), between the cells

electrical

_______ cells line CNS cavities and produce cerebrospinal fluid;

ependymal

• A nerve is a bundle of many parallel axons organized in three layers: an ________ around a single axon, a _______ around a fascicle, and an ______ around all of the fascicles.

endoneurium, perineurium, epineurium

• A mature neuron typically cannot undergo mitosis because it does not have which structure (s)? a. a nucleus b. ribosomes c. centrioles d. mitochondria

c. centrioles

Which nervous system function and term are correctly paired? a. respond to information-receptor b. respond to information-effector c. collect information-effector d. collect information-stimuli

b. respond to information-effector

Which neurons are located only within the CNS? a. motor neurons b. unipolar neurons c. sensory neurons d. interneurons

d. interneurons

Which structure or cell is responsible for increasing the propagation rate of a nerve impulse? a. motor neuron b. receptor c. neurolemmocyte d. ganglion

c. neurolemmocyte

Which glial cells help produce CSF in the CNS? a. satellite cells b. microglial cells c. ependymal cells d. astrocytes

c. ependymal cells

Which of the following is not a part of the CNS? a. microglial cell b. spinal cord c. neurolemmocyte d. brain

c. neurolemmocyte

Which of these cells transmits, transfers, and processes a nerve impulse? a. neurolemmocte b. astrocyte c. neuron d. oligodendrocyte

c. neuron

Which structures facilitate interactions between presynaptic and postsynaptic membranes in an electrical synapse? a. neurofibril nodes b. gap junctions c. terminal arborizations d. neurotransmitters

b. gap junctions

. Which of the following best describes an epineurium? a. a thick, dense irregular connective tissue layer enclosing the nerve b. a group of axons c. a delicate laver of areolar connective tissue d. a cellular layer of dense regular connective tissue

a. a thick, dense irregular connective tissue layer enclosing the nerve

Dendrites Conducts information to the

cell body

A soma is another name for the of a neuron. • axon • myelin sheath O axon hillock • dendrites • cell body

Correct Answer cell body

Dendrites transfer information the cell body. • toward • from

Correct Answer toward

If a sensory neuron detects a painful stimulus, it will send a signal to an interneuron in the CNS for processing. This may result in a motor neuron stimulating muscle contraction, moving the body away from the painful stimulus. What are the structural classifications of the three neurons in this example? (listed in the order they appear) • Unipolar, bipolar, multipolar • Unipolar, multipolar, multipolar • All are unipolar • Multipolar, bipolar, unipolar • Multipolar, multipolar, unipolar • All are bipolar • All are multipolar.

Correct Answer Unipolar, multipolar, multipolar

The neuron needs a high amount of energy or ATP. The ATP is created by the • chromatophilic substance O nucleus O mitochondria O nucleolus

Correct Answer mitochondria

Dendrites branch off of the axon hillock • cell body • synaptic knobs • axon

Correct Answer cell body

The cell bodies of neurons are found in the dorsal root ganglia. • bipolar • multipolar • unipolar

Correct Answer unipolar

Bipolar neurons have one axon and dendrite. • one • two • three

Correct Answer one

Sensory neurons carry information the central nervous system. efferent, away from efferent, toward afferent, toward afferent, away from

Correct Answer afferent, toward

The cell bodies of most motor neurons lie in the O spinal cord O cranial nerves • dorsal root ganglia O spinal nerves

Correct Answer spinal cord

T/F: astrocytes also replace damaged neurons.

true

A damaged axon within the PNS can regenerate if • some dendrocytes remain • some oligodendrocytes remain O none of the cell body remains O some neurilemma remains

Correct Answer some neurilemma remains

Synapses occur where axons contact which of the following? blood vessels • gland cells other neurons _muscle cells

Correct Answer gland cells other neurons muscle cells

Neuronal pools are made of • interneurons • motor neurons • sensory neurons

• interneurons

The neuroectoderm is the name for the cells that make up the neural O folds • groove • crest cell • plate

Correct Answer plate

Flashcards: Nervous Tissue