Biology 242 Part 1

Front 1

Central Nervous System

Back 1

Brain & Spinal cord
Neuroglial : astrocytes, oligodendrocytes, microglia, & ependymal
Functions : Sensory, Motor, Integrative

Front 2

Peripheral Nervous System

Back 2

All nervous tissue outside the CNS
Cranial Nerves (12), Spinal Nerves (31 pairs), Ganglia, & Enteric Plexuses
Divisions : Somatic, Autonomic, & Enteric
Neuroglia : neurolemmocytes (Schwann) & satellite cells

Front 3

Sensory function

Back 3

detect internal/external stimuli and carry information into the brain and spinal cord
incoming

Front 4

Motor function

Back 4

elicit appropriate motor response by activating effectors
outgoing

Front 5

Integrative function

Back 5

process sensory information by analyzing it and making appropriate responses
integrating the information

Front 6

Somatic Nervous System

Back 6

Voluntary
Contracts skeletal muscles
Neurons :
(1)sensory - convey info from somatic receptors in the head, body wall, limbs, and receptors for special senses (vision, hearing, taste, smell) to the CNS
(2)motor - conduct impulses from the CNS to skeletal muscles

Front 7

Autonomic Nervous System

Back 7

Involuntary
Smooth & Cardiac muscles and glands
Parasympathetic/sympathetic system
Neurons:
(1)sensory - convey info from autonomic sensory receptors in visceral organs (stomach and lungs) to the CNS
(2)motor - conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands

Front 8

Enteric Nervous System

Back 8

Involuntary
Smooth muscle, glands, endocrine cells of GI tract ("brain of the gut")
Neurons in enteric plexuses that extend over most of the GI tract and function independently; communicate with the CNS via sympathetic and parasympathetic neurons
Neurons:
(1)sensory - monitor chemical changes within the GI tract and the stretching of its walls
(2)motor - govern contraction, secretion, and activity of endocrine cells in the GI tract

Front 9

2 main nerve cells

Back 9

Neurons : action potential producing cells
Neuroglial : structural cells, support neurons, more common than neurons [wrap around capillaries in the brain to make the blood brain barrier]

Front 10

Parts of a Neuron

Back 10

i) cell body : where the cytoplasm & the organelles are stored
ii) dendrites : incoming to the cell body (usually 1+)
iii) axon : outgoing from the cell body to another neuron, muscle fibre, or gland cell
iv) cytoplasm : fluid in the body

Front 11

Nissl bodies

Back 11

rough endoplasmic reticulum in a neural cytoplasm
protein synthesis

Front 12

Axon Hillock

Back 12

where the axon joins the cell body

Front 13

Initial segment

Back 13

where the action potential starts

Front 14

Axolemma

Back 14

membrane around the axon, phospholipid bilayer

Front 15

Axoplasm

Back 15

the cytoplasm of an axon

Front 16

Axon Terminal

Back 16

(telodendria)
last portion of the axon

Front 17

Synaptic Bulb

Back 17

stores synaptic vesicles

Front 18

Trophic Factors

Back 18

anything that increases growth and repair

Front 19

Slow axonal transport

Back 19

moves materials about 1-5 mm/day
supplies new axoplasm to developing or regenerating axons and replenishes axoplasm in growing and mature axons
Direction : out from the cell body

Front 20

Fast axonal trasport

Back 20

moves materials 200-400 mm/day
uses proteins that function as motors to move materials along the surfaces of microtubules
Direction : both - out from the cell body (anterograde) and into the cell body (retrograde)

Front 21

Structural classification of neurons

Back 21

i) multipolar : multiple dendrites, one main axon, common in CNS
ii) bipolar : one main dendrite, one main axon, involved in special senses (sight, smell, balance)
iii) unipolar : (pseudounipolar), fusion of dendrite and axon into one long process, involved in general senses (touch, pressure, vibration)

Front 22

Purkinje cells

Back 22

in the cerebellum
control heart muscles

Front 23

Pyramidal cells

Back 23

in the cerebral cortex
pyramid shaped bodies
descending motor tracts in voluntary motor system

Front 24

Astrocytes

Back 24

star-shaped
fibrous or protoplasmic
form part of the blood brain barrier
Functions: (1)strengthen the nerve they are adjacent to
(2)control chemical environment
(3)help with the formation of synapsis

Front 25

Oligodendrocytes

Back 25

cells in the CNS that produce the myelination around nerves (several axons at a time)

Front 26

Microglia

Back 26

phagocytes of the brain
fight infections

Front 27

Ependymal

Back 27

cuboidal or columnar simple epithelium
part of producing cerebral spinal fluid
line the ventricles

Front 28

Neurolemmocytes

Back 28

(Schwann cells)
myelinating cells of the PNS
only myelinate on axon at a time

Front 29

Satellite Cells

Back 29

surround cell bodies in peripheral nerves
key supportive cells
Functions: (1)regulate movement of fluid
(2)exchange nutrients across membranes

Front 30

What cells control myelination of the PNS neurons?

Back 30

Schwann cells (Neurolemmocytes)

Front 31

What cells control myelination of the CNS neurons?

Back 31

Oligodendrocytes

Front 32

What is myelin?

Back 32

lipid and protein
several layers of wrapping

Front 33

Neurolemma

Back 33

only in the PNS
part of the neurolemmocyte
results in better regeneration of nerves

Front 34

Nodes of Ranvier

Back 34

(neurofibril node)
no myelination
potassium and sodium pumps are found here

Front 35

Ganglion

Back 35

collection of cell bodies in the PNS

Front 36

Nucleos

Back 36

collection of cell bodies in the CNS

Front 37

Nerves

Back 37

collection of axons in the PNS

Front 38

Tract

Back 38

bundle of axons in the CNS

Front 39

Gray Matter

Back 39

collection of cell bodies, dendrites, neuroglial cells, unmyelinated axons, and axon terminals

Front 40

White matter

Back 40

made up of myelinated axons

Front 41

Two ways that neurons communicate

Back 41

Action potentials & graded potentials

Front 42

Action potential

Back 42

electrical producing structures
long-distance electrical communication

Front 43

Graded potential

Back 43

short-distance electrical communication
varying strength
can join other GPs and make an AP

Front 44

Upper motor neuron

Back 44

inside the CNS
leaves the CNS

Front 45

Lower motor neuron

Back 45

carries information out to the skeletal muscle/effector

Front 46

Membrane Potential

Back 46

difference in electrical charge from the outside to the inside of an axon

Front 47

RMP

Back 47

the voltage difference across the membrane of a neuron at rest (70mV)
when the inside is more negative than the outside of the cell
resting state of the membrane potential
the separation of positive and negative charges creates potential energy

Front 48

Ion channels

Back 48

i) Leak channels
ii) ligand-gated channels
iii) mechanically gated channels
iv) voltage-gated channels
ions move from an area of high concentration to an area of low concentration (or - to + areas)
channels open and close due to the presence of gates

Front 49

Production of AP and GP depends on...

Back 49

i) the RMP/ membrane potential
ii) the gates of the ion channels
iii) electrochemical gradient
AP and GP are produced when ion channels open and close to let -/+ charged ions flow back and forth like electrical current down their electrochemical gradient

Front 50

Electrochemical gradient

Back 50

the different concentration of charged elements between the inside and the outside of the cell

Front 51

Leakage channels

Back 51

randomly open and close
random amounts of electrolytes leak through the channels (usually potassium)
found in nearly all cells (dendrites, cell bodies, and axons of all types of neurons)

Front 52

Voltage-gated channels

Back 52

open and close in response to an electrical gradient (a change in membrane potential)
on the axons of all types of neurons

Front 53

Ligand-gated channels

Back 53

opens and closes in response to the binding of a ligand stimulus (neurotransmitters/ hormones)
in the dendrites of some sensory neurons, and in the dendrites and cell bodies of interneurons and motor neurons

Front 54

Mechanically-gated channels

Back 54

opens and closes in response to mechanical stimulation in the form of vibration, touch, pressure, or tissue stretching
(the mechanical stimulus distorts the channel and opens the gate)
in the dendrites of neurons that control the general senses, and receptors that monitor the stretching of internal organs

Front 55

3 major factors that create a RMP

Back 55

i) unequal distribution of ions between the inside and outside of the cell (creates an electrical potential)
ii) inability of most anions (-) to leave the cell (don't leave as quickly as + ones do)
iii) electrogenic nature of the Na+/K+ ATPase (enzyme), which is needed to operate the pumps

Front 56

Generator potential

Back 56

general senses (touch, pressure, vibration, heat/cold)

Front 57

Receptor potential

Back 57

special senses (smell, taste, hearing)

Front 58

Summation

Back 58

adding a number of generator/action potentials together to hopefully produce a stronger stimulus

Front 59

Hyperpolarizing GP

Back 59

made the inside more negative than the RMP

Front 60

Depolarizing gp

Back 60

made the incise more positive and produced an electrical current