General Properties Of Nerve Tissues

Question 1

nervous sysytem is divided into

Answer 1

CNS (brain and spinal cord) and PNS (other nerves outside the CNS and associated ganglia)

Question 2

Functionally NS is divided into

Answer 2

sensory which transmits electrical impulses to CNS

motor which transmits impulses from CNS to other parts of the body

Question 3

cells of NS

Answer 3

nerve cells (neurons) excitable cells which conduct electrical impulses

glial cells (neuroglia) nonexcitable which support, nurture and protect neurons

Question 4

neurons and neuroglial cells derive from the embryonic tissue :

Answer 4

neural tube and neural crest

Question 5

how the nervous system communicates

Answer 5

1) receives inputs from the external and internal environment
2) analyses and integrates the inputs
3) an output is produced

Question 6

properties of neurons

Answer 6

excitability; ability to respond to stimuli

conductivity; ability to produce electrical signals to different parts of body

functional polarity; travels to different directions

Question 7

name given to a collection of nerve cell bodies in CNS and in PNS

Answer 7

in CNS is called nucleus

in PNS is called ganglia

Question 8

name given to bundle of nerve fibers in CNS and PNS

Answer 8

in CNS is called tract

in PNS is called nerve

Question 9

somatic NS

Answer 9

• conscious voluntary control

- provides sensory and motor innervations to all parts of the body except viscera, smooth, cardiac muscle and glands

Question 10

autonomous NS

Answer 10

• involuntary control
• provides efferent involuntary motor innervations to smooth, cardiac muscle and glands
• provide afferent sensory innervation from viscera
• subdivided into sympathetic and parasympathetic

Question 11

morphologic classification of neurons

Answer 11

unipolar
bipolar
multipolar
pseudounipolar

Question 12

functional classification of neurons

Answer 12

sensory (afferent) neurons; take responses from PNS to CNS

motor (efferent) neurons; take responses from CNS to PNS

interneurons; connect motor neurons to sensory neurons

Question 13

axon length in neurons

Answer 13

long; Golgi type I mostly motor neurons

short; Golgi type II mostly interneurons

Question 14

basic staining used to see nissl bodies

Answer 14

toluidin blue because basic nissl bodies are highly basophilic

Question 15

difference between dendrites and axons

Answer 15

• dendrites have abundant ribosomes and in ER while axon have no organelles involved in protein synthesis
• dendrites have irregular surface and many spines while axon has many mitochondria
• dendrites have no uniform diameter while axons have uniform diameter

Question 16

components of cytoskeleton of neuron

Answer 16

neurofibrils, microtubules, microfilaments

Question 17

function of cytoskeleton

Answer 17

• structural support
• axonal flux regulation
• release of neurotransmitters at the synapse and axonal support

Question 18

two types of axonal flux

Answer 18

FAST;

• anterograde: enzymes, neurotransmitters, structural proteins
• retrograde: molecules for recycling or degradation.

SLOW;
-cytoskeleton subunits, cytoplasmic proteins

Question 19

function of neuroglial cells

Answer 19

-surround neurons
-provide mechanical and chemical support
regulating the delivery nutrients
-synapse stabilisation
can proliferate

Question 20

types if neuroglial cells in CNS

Answer 20

astrocytes
oligodendrocytes
ependymal cells
microglia

Question 21

types of neuroglial cells in PNS

Answer 21

schwann cells

satellite cells

Question 22

characteristics and function of astrocytes

Answer 22

• largest neuroglial cells
• star shaped with thin and rich prolongements

functions;

• structural support
• regulation of metabolic exchanges
• repair by forming scar tissue after injury to the CNS
• form Blood Brain Barrier

Question 23

types of astrocytes

Answer 23

fibrous astrocytes; found in white matter , smooth elongation and build the BB

protoplasmic astrocytes; found in gray matter, rough elongation and control vessel trafficking

Question 24

characteristics and function of oligodendrocytes

Answer 24

• most common
• located in both grey and white matter
• produce myelin that surrounds and protects the axon
• analogous to schwann cells in PNS

Question 25

characteristics and function of ependymal cells

Answer 25

• form epithelial membrane lining the cerebral cavities and central canal of spinal cord
• produce CSF
• may function as stem cells (because of proliferation and differentiation)

Question 26

characteristics and function of microglia

Answer 26

• mesenchymal origin
• macrophage alike and perform phagocytic functions
• cytoplasm contains many lysosomes
• function in phagocytosis, removal of pathogens and cell debris from the brain