Chapter 16 nervous tissue

Question 1

The definition of the nerve, ganglion, enteric plexuses, and receptor.

Answer 1

A nerve - bundle of axons

ganglia (swelling/knot) - small masses of nervous tissue (neural cell bodies) outside the brain and spinal cord

enteric plexuses - network on neurons located in walls of gi tract organs, help regulate digestive system activites

sensory receptors - specialized nerve endings

Question 2

The organization of the nervous system on the basis of structural and functional aspects

Answer 2

CNS
brain, spinal cord

PNS
cranial nerves - from brain

spinal nerves - from spinal cord

sensory/afferent neurons - transmit nerve impulses from sensory receptors to CNS

motor/efferent - transmit nerve impulses from CNS to muscles and glands

Question 3

Functional organization of NS

Answer 3

Sensory components of PNS

SNS (somatic and special sensory receptors and somatic neurons) -> CNS brain and spinal cord

ANS (autonoimic sensory receptors and autonomic sensory neurons) -> CNS

ENS (enteric sensory receptors and eteric sensory nerons in enteric plexuses of gi tract) -> CNS

Motory components of PNS
CNS -> somatic motar neurons (voluntary) -> skeletal muscles (effector)

CNS -> autonomic motor neurons (involuntary) sympathetic and parasympathetic divisions -> smooth muscle, cardiac muscle, and glands (effector) ALSO DOWN BELOW

Enteric motor neurons (involuntary) in enteric plexuses of GI tract -> smooth muscle, glands, and endocrine cells of Gi tract (effector)

Question 4

Function of NS

Answer 4

sensory function (sensory receptors)

• detect stimuli in internal and external environments
• resulting in sensory info being transmitted by sensory or afferent neurons to brain or spinal cord

integrative function (interneuron)

• analyzes sensory info to provide perception
• storing some
• making decisions regarding behaviours

motor function (motor/efferent neurons)

• respond to integration decisions by initiating actions in effectors
• including muscle fibers and glandular cells

Question 5

Somatic nervous system

Answer 5

SNS in PNS

Somatic sensory neurons

• somatic sensory neurons - convey info from sensory receptors in skin, skeletal muscles, joints,
• for special senses (vision, hearing, taste, smell) to CNS

somatic motor neurons

• convey info from CNS to skeletal muscles only
• output of info from CNS that results in muscular contration

Question 6

Autonomic nervous system

Answer 6

autonomic of PNS both sensory and motor

sensory

• autonomic (visceral) sensory neurons
• info mainly from visceral organs (smooth muscle organs in thorax, abdomen, and pelvis) to CNS

autonomic motor neurons

• convey info from CNS to smooth muscle, cardiac, and glands
• cause muscles to contract and glands to secrete

Question 7

The differences between neurons and neuroglia

Answer 7

Neurons
Highly specialized cells. They do not have the ability to undergo mitotic divisions.

Neuroglia

• similar but outnumber neurons
• support, nourish, protect neurons, maintain interstitial fluid that bathes them
• continue to divide throughout individuals’ lifetime

Question 8

Structure and function of typical neurons- a function of the dendrites, cell body, axons, and axon terminal

Answer 8

Cell body - protein synthesis, contains the nucleus

Dendrite - recieve/input zone

axon hillock - trigger zone

axon - output zone, carries nerve impulses toward another neuron, muscle fiber, or gland

Question 9

Structures belong to the input zone, trigger zone, output zone

Answer 9

Dendrite - input zone
axon hillock - trigger zone
axon - output zone

Question 10

Name of the neuroglia whether they belong to the central nervous system (CNS) or PNS and their brief functions

Answer 10

CNS

astrocytes
-microfilaments provide strength
unique permebility chracteristics of endothelial cells (BBB)
-maintain appropriate chemical environment for generation of nerve impulses
-learning and memory

oligodendrocytes -

• forms and maintains protective covering
• myelin sheath insulates axon and increases speed of nerve impulses

microglia

• originate in red bone marrow
• migrate in CNS
• phagocytes, remove cellular debris, microbes, damaged nervous tissue

ependymal cells

• produce, monitor, assist in circulation of CSF
• form blood cerbrospinal fluid barrier

PNS
schwann cells
-encircle PNS axons and form myelin sheath around axon
-axon regeneration easily accomplished in PNS

(neurolemmocytes)

satellite cells
exchange of materials between neuronal cell bodies and interstitial fluid