Nervous tissue

Question 1

Central Nervous System

Answer 1

• this consists of the brain and the spinal cord
• this processes and coordinates sensory input and motor output
• the area of higher intelligence, memory, learning and emotion

Question 2

Peripheral Nervous System

Answer 2

• this is divided into afferent and efferent systems

- this is anything outside of the CNS

Question 3

Afferent Nervous system

Answer 3

• carries sensory information to CNS

- receptors monitor the environment which then sends information to the CNS

Question 4

Efferent Nervous system

Answer 4

• this is then divided into the somatic and the autonomic nervous systems
• the efferent pathway is the pathway that is leaving the CNS and an effect will be coming within the body

Question 5

somatic motor system

Answer 5

this controls the skeletal muscles

• this can be voluntary and involuntary
  ex. moving your arm to drink water is done consciously but moving you hand off a hot stove is a reactionary response

Question 6

visceral nervous system

Answer 6

• this is the unconscious actions that the body recognizes in the afferent and efferent
• afferent would be using receptors to see what is happening internally
• efferent would be actions that are taken in response to what the afferent system said was happening
• this regulates smooth muscle, cardiac muscle, and glandular activity.
• this is always involuntary
  ex. heartbeat, digestion

Question 7

sensory nervous system

Answer 7

this is the afferent nervous system

- can be visceral or somatic

Question 8

motor nervous system

Answer 8

this is the efferent nervous system

-this can be visceral or somatic

Question 9

visceral motor system

Answer 9

• would be secretions from glands or contractions of smooth muscle in response to sensory input
• this is unconscious

Question 10

Somatic motor system

Answer 10

this would be a voluntary movement and involves the innervation of skeletal muscle
-this is concious

Question 11

visceral sensory system

Answer 11

• the body is watching for internal environmental changes with receptors
• the body looks how much is being secreted from glands or how the blood vessels are dilated and this then goes to the CNS which will make a decision on what the approbate visceral motor response will be
• this is unconscious

Question 12

somatic sensory system

Answer 12

• as external changes such as touch, pain occur, this sends that information to the CNS to allow it to react
• this is concious

Question 13

dendrite

Answer 13

sensory processes that are stimulated by changes of activities by other cells

Question 14

axon

Answer 14

conducts a nerve impulse toward the axon terminal

Question 15

neuroglia

Answer 15

these are glial cells

• they have the ability to divide
• different types in the CNS and PNS

Question 16

soma

Answer 16

• another name for cell body

- contains the nucleus,mitochondria, ribosomes, and other organelles and inclusions

Question 17

5 characteristics of Neurons

Answer 17

1. send electrical signals to glands, other neurons or muscles
2. live for a lifetime
3. cannot divide
4. high metabolic rate (they need a good blood supply
5. most cell bodies in the CNS

Question 18

why are most of the cell bodies in the CNS

Answer 18

this is because when there is damage to the cell body the neuron will die
-the CNS is surrounded by bone so it is really important for them to be in there or near it for protection

Question 19

collection of cell bodies in the CNS

Answer 19

nucleus

Question 20

collection of cell bodies in the PNS

Answer 20

ganglian

Question 21

collection of axons traveling to a common destination in the PNS

Answer 21

nerve

Question 22

collection of axons traveling to a common destination in the CNS

Answer 22

tract or column

Question 23

endoneurium

Answer 23

this is the connective tissue that is around each axon

Question 24

perineurium

Answer 24

this in the connective tissue around individual fascicles

Question 25

Fascicle in regards to the nervous system

Answer 25

this is a group of axons

Question 26

epineurium

Answer 26

connective tissue around the entire nerve

Question 27

synapse

Answer 27

this is the place of neuronal communication | -this is at the end on one axon and at the cell body or another neuron

Question 28

astrocytes

Answer 28

-a glial cell in the CNS -this is star shaped and has long processes that reach out through the CNS -these are the largest and the most numerous of all the glial cells Functions: -maintain blood/brain barrier -provide structural support -regulate ion, nutrient, and dissolved gas concentration -absorb and recycle neurotransmitters -form scar tissue after injury

Question 29

oligodendrocytes

Answer 29

-a glial cell in the CNS -small cell bodies and shorter processes than astrocytes Functions: -mylinate the CNS axons -provide structural framework

Question 30

what is the main difference between oligodendrocytes and Schwann cells

Answer 30

- the Schwann cells can only myelinate on axon and only one part of one axon where as oligodendrocytes can myelinate multiple axons and multiple parts of an axon

Question 31

microglia

Answer 31

-a glial cell in the CNS - these are the smallest of the glial cells Fuctions: remove cell debris, waste and pathogens using phagocytosis -sometimes called the "immune system of the brain"

Question 32

ependymal cells

Answer 32

-a glial cell in the CNS -cubodial or columnar in shape and have cilia Functions: -lines the ventricles (brain) and central canal (spinal cord) -assist in producing, circulating and monitoring how cerebral spinal fluid

Question 33

Satellite cells

Answer 33

-a glial cell in the PNS Functions: -surround neuron cell bodies in peripheral ganglia -regulate the echange of nutrients and waste products between the ECF and the cell body -isolates neuron from stimuli not intended to pass from neuron to neuron

Question 34

Schwann cells

Answer 34

``` -a glial cell in the PNS Functions: - surround the axons in the PNS -myelinate peripheral axons -participate in the repair process after an injury ```

Question 35

glial cells

Answer 35

- these can divide - provide protection, insulation and nourishment for neurons - provide scaffolding for neurons - much more abundant than neurons * not excitable so cannot send signals

Question 36

bipolar neuron

Answer 36

this has dendrites that merge together to form a single dendrite which then travels to the cell body which is in the middle and then goes to the axon -very rare and is used in special senses (sight and smell)

Question 37

pseudounipolar neuron

Answer 37

- dendrites converge and meet the axon early in the pathway - looks like the cell body is hanging off - used to sense touch in the periphery to the CNS

Question 38

multipolar neuron

Answer 38

- this is the most common | - dendrites surround the cell body and a signal is sent out through one axon

Question 39

convergence

Answer 39

this is when many neurons synapse at a single post synaptic neuron - this allows for amplification of a signal in some cases - may also allow for an increased strength of signal which may be required for the post synaptic neuron to fire

Question 40

divergence

Answer 40

this is when on neuron synapses onto many post synaptic neurons -this allows for a message to be widespread and alert many places of what is going on

Question 41

node of ranvier

Answer 41

this is the space between two schwann cells in the myelin sheath

Question 42

myelin

Answer 42

- a lipid rich substance with a whiteish appearance (makes up the white matter of the brain and spinal cord) - in the CNS this will be done by the ogliodendrocytes and in the PNS this will be done by the schwann cells

Question 43

myelination

Answer 43

this is the process of wrapping an axon in a myelin sheath -a Schwann cell wraps itself around the axon and keeps wrapping over and over, all the while forcing the cytoplasm into the superficial layers

Question 44

myelin sheath

Answer 44

this insulates, improves conductance and protects the axon | -made of many schwann cells on one axon or many ogliodendcytes

Question 45

gliomas

Answer 45

this is a tumor of the glial cells ex. astrocytoma = tumor of the astrocytes - oligodendroglioma=tumor of the oligiodendrocytes - mixed glioma = many cell types within

Question 46

what are more difficult to resect or remove? Astocytomas or olgodendrogliomas?

Answer 46

Astrocytomas because they have less defined boarders because these cells stretch throughout the CNS which makes it difficult to know if you actually got the whole thing

Question 47

axon regneration

Answer 47

- this can only occur in the PNS - the axon is broken and then the schwann cells are able to create a regeneration tube and secrete chemicals to promote axonal regeneration but the oligodendrocytes do not do either of these things so not possible in CNS

Question 48

what other than the oligodendrocytes in the CNS prevents axon regeneration?

Answer 48

the astrocytes wall off areas in the brain that are damaged to isolate the area and protect surrounding areas and that makes it hard for axons to regenerate and break through the barrier (oligodendrocytes can not make the regeneration tube and secrete chemicals that inhibit regeneration)

Question 49

Wallerian Degeneration

Answer 49

An injury to an axon occurs which causes anything after the injury to break down or "degenerate" -anything before the injury is fine but anything after fragments off