Nervous System

Question 1

Afferent

Answer 1

Carry or move inward or toward a central structure

Question 2

Blood-brain barrier

Answer 2

Protective mechanism that blocks specific substances found in the bloodstream from entering delicate brain tissue

Question 3

Efferent

Answer 3

Carry or move away from a central structure

Question 4

Limbic system

Answer 4

Complex neural system located beneath the cerebrum that’s controls basic emotion s and drives and plays an important role in memory

Question 5

Neurilemma

Answer 5

Additional external myelin sheath that is formed by schwann cells and found only on axons in the peripheral nervous system.

Question 6

Ventricle

Answer 6

Organ chamber or cavity that receives or holds fluids

Question 7

Neurons

Answer 7

One of the two principal cell types that composed the nervous system

Along with neuroglia constitute the tissue of the body

Transmit impulses

Identified by the direction impulses travel, afferent— toward and efferent— away from the brain or spinal cord

3 major structures of the neuron are
1. Cell body, 2. Axon, 3. Dendrites

Question 8

Cell body

Answer 8

Is the enlarged structure of the neuron that contains the nucleus of the cell and various organelles

Question 9

Dendrites

Answer 9

Branching cytoplasm projection

Carry impulses to the cell body

Resemble tiny branches on a tree, providing additional surface area for receiving impulses from other neurons

Question 10

Axons

Answer 10

Carry impulses from the cell body

Are threadlike extensions of nerve cells that transmit impulses to dendrites or other neurons as well as muscles and glands

Posses a white, lipoid covering myelin sheath

Question 11

Myelin sheath

Answer 11

A white lipoid covering in the axons of the neuron.

Covering acts as an electrical insulator that reduces the possibility of an impulse stimulating adjacent nerves

Also accelerates impulse transmission through the axon

Question 12

Schwann cell

Answer 12

A Neuroglial cell that forms the myelin sheath in the peripheral nervous system that wraps tightly around the axon.

Question 13

Neurilemma

Neurolemma

Answer 13

The exterior surface of the Schwann cell forms a thin tube called neurilemma

Does not disintegrate after an axon has been crushed or severed (remains intact)

Intact sheath provides a pathway for possible neuron regeneration after injury

Question 14

Nodes of ranvier

Answer 14

Short, unmyelinated spaces between adjacent segments of the myelin sheath

Help speed the transmission of impulses down the axon because an impulse jumps across the nodes at a faster rate than it’s able to travel through the myelinated axon.

Question 15

Synapse

Answer 15

Functional connection between two neurons or between a neuron and it’s effector organ (muscle or gland) is a gap space called a synapse l

Question 16

Neuroglia

Answer 16

One of the two principal cell types that composed the nervous system

Along with neurons constitute the tissue of the body

Cells that support neurons and bind them to other neurons or other tissues of the body

Don’t transmit impulses but provide a variety of activities essential to the proper functioning of neurons

Neuroglia means nerve glue

They supply nutrients and oxygen to neurons and assist in other metabolic activities

Four major types of neuroglia are
1.astrocytes, 2. Oligodendrocytes, 3. Microglia, 4. Ependyma

Question 17

Astrocytes

Answer 17

Are star-shaped neuroglia

Provide three-dimensional mechanical support for neurons and form right sheaths around a the capillaries of the brain

Perform mildly phagocytic functions in the brain and spinal cord

Question 18

Oligodendrocytes

Answer 18

Also called oligodendroglia

Responsible for developing myelin on axons of neurons in the central nervous system

Question 19

Microglia

Answer 19

Smallest of the neuroglia

Possess phagocytic properties and may become very active during times of infection

Question 20

Ependyma

Answer 20

Ciliates cells that line fluid-filled cavities of the central nervous system especially the ventricles of the brain

Assist in the circulation of cerebrospinal fluid (CSF)

Question 21

Central nervous system (CNS)

Answer 21

Major division part of the nervous system

Consists of the brain and spinal cord

It’s nervous tissue is classified as white matter or gray matter

Bundles of axons with their white lipoid myelin sheath constitute white matter

Unmyelinated fibers, dendrites, and nerve cell bodies make up the gray matter of the brain and spinal cord

Question 22

Peripheral nervous system (PNS)

Answer 22

Major division part of the nervous system

Consists of 12 pairs of cranial nerves and. 31 pairs of spinal Nerves

Composed of all nervous tissue located outside the spinal column and skull

Question 23

Cerebrum

Answer 23

The largest uppermost portion of the brain

Consists of two hemispheres divided by a deep longitudinal fissure, or grove

Question 24

Corpus callosum

Answer 24

Joins the hemispheres of the cerebrum permitting communication between the right and left sides of the brain

Major functions include: sensory perception and interpretation, language, voluntary movement, and memory

Question 25

Limbic system

Answer 25

Located beneath the cerebrum also known as an emotional brain

Is essential for survival and works in conjunction with the thinking brains

Controls such behaviors as rage, fear, and anger and the emotional aspects such as food enjoyment and sexual behavior

Question 26

Cerebellum

Answer 26

The second largest structure of the brain

Occupies the posterior portion of the skull

Most functions involve movement, posture, or balance

Cerebrum initiates muscular movement while the cerebellum coordinates and refined it

Question 27

Diencephalon

Answer 27

Also called interbrain

Composed of many smaller structures including the thalamus and hypothalamus

Thalamus receives all sensory stimuli except olfactory and processes and transmits them to the appropriate centers in the cerebral cortex

Hypothalamus regulates involuntary activities such as heart rate, body temperature, and fluid balance. Also controls many endocrine functions

Question 28

Brainstem

Answer 28

Completes the last major section of the brain

Composed of three structures:
1.midbrain: called mesencephalon which separated the cerebrum from the brainstem

2. medulla: attaches to the spinal cord
3. Pons: “bridge”; connects the midbrain to the medulla

Brainstem is a pathway for impulse conduction between the brain and spinal cord. Also is the Origin of 10 of the 12 pairs of cranial nerves and control respiration, blood pressure, and heart rate

Is the site that controls the beginning and end of life.

Question 29

Spinal cord

Answer 29

Transmits sensory impulses from the body to the brain and motor impulses from the brain to muscles and organs of the body.

Question 30

Meninges

Answer 30

The brain and spinal cord receive limited protection from three coverings called meninges which are dura mater, arachnoid, and pia mater

Beneath the dura mater is a cavity called the subdural space which is filled with serous fluid

Question 31

Dura mater

Answer 31

The outermost covering of the brain and spinal cord.

It’s rough, fibrous, and dense and composed primarily of connective tissue

Because of its thickness this membrane is also called pachymeninges

Question 32

Arachnoid

Answer 32

The middle covering and has a spider-web appearance

Fits loosely over the underlying structures

Called the leptomeninges

Question 33

Cerebrospinal fluid

Answer 33

A colorless fluid that contains proteins, glucose, urea, salts, and some white blood cells

Circulated around the spinal cord and brain and through ventricles located within the inner portion of the brain

Question 34

Hydrocephalus

Answer 34

A collection of cerebrospinal fluid in the brain caused by an interference in the absorption of the fluid

Question 35

Pia mater

Answer 35

The innermost meninges

Directly attached to the brain and spinal cord

Contains numerous blood vessels and lymphatics that nourish the underlying tissues

Called the leptomeninges

Question 36

Cranial nerves

Answer 36

Originate in the base of the brain and emerge through openings in the base of the skull

May be sensory, motor, or a mixture of both

Question 37

Sensory nerves

Answer 37

Are afferent

Receive impulses from the sense organs, including eyes, ears, nose, tongue, and skin and transmit them to the CN

Question 38

Motor Nerves

Answer 38

Are efferent

Conduct impulses to muscles and glands

Question 39

Mixed nerves

Answer 39

Composed of sensory and motor fibers

Example: facial nerve
Acts in a motor capacity by transmitting impulses for smiling or frowning.
Acts in a sensory capacity by transmitting taste impulses from the tongue to the brain

Question 40

Spinal nerves

Answer 40

Emerge from the intervertebral spaces in the spinal column and extend to various locations of the body

All 31 pairs of spinal nerves are mixed nerves

Anterior root contains motor fibers
Posterior root contains sensory fibers

Both roots untied to form the spinal nerve that has afferent and efferent qualities

Question 41

Somatic & autonomic nervous systems

Answer 41

Somatic- motor impulses transmitted to muscles under conscious control (walking and talking)

Autonomic- motor impulses transmitted to glands and muscles not under conscious control (heart rate, respiration, digestion, pupil diameter, and so forth)