nervous system

Question 1

the central nervous system

Answer 1

nervous tissue that largely consists of the brain and spinal cord

Question 2

the peripheral nervous system

Answer 2

can be categorized further but is made up of every neuron outside the central NS

Question 3

function of the nervous system

Answer 3

• sensation
• integration
• motor
  allowing the body to do many tasks

Question 4

the nervous tissue is made of two types of cells

Answer 4

• neurons
• glial cells

Question 5

how do neurons send messages

Answer 5

via electrical activity called action potentials

Question 6

glial cells

Answer 6

are supporting cells for the neurons they help nourish and protect the neurons as well as physically supporting them, they also support them by being more efficient and effective.

Question 7

the types of glial cells

Answer 7

• Schwann cells
• oligodendrocytes
• astrocytes
• ependymal cells

Question 8

neuron as a cell

Answer 8

it has a plasma membrane, a nucleus, and a cytoplasm.

Question 9

parts of a neurons

Answer 9

cell body - (soma) where the nucleus and most organelles are located
dendrites - part that receives signals from other neurons or sensory receptors
axon - part that carries the impulse towards another structure

Question 10

neuron classification

Answer 10

structural - what they look like
- functional - which direction they travel in

Question 11

structural classifications

Answer 11

how many processes extend from the soma
- multipolar - more than two processes
- bipolar - two processes extending from the soma
- pseudo unipolar - looks like one processes extending from the soma however there is actually two

Question 12

functional classifications

Answer 12

sensory (afferent) - impulses that travel from the periphery NS to the CNS bipolar and pseudo
motor (efferent) - impulses that travel from the CNS to the PNS all multipolar
interneurons - found in the CNS all multipolar

Question 13

myelin sheaths

Answer 13

layer of fat that encircles the axon to insulate it helping speed up the transmission

Question 14

associated structures

Answer 14

glial cells
oligodendrocytes (CNS)
and Schwann cells (PNS)
make the myelin sheath

Question 15

sensory receptors

Answer 15

stimulus are detected by sensory neurons and receptors they can be apart of together

Question 16

types of sensory receptors

Answer 16

• encapsulated endings
• free ‘nerve’ endings
• specialised receptor cells

Question 17

nerves

Answer 17

are cells that make up nervous tissue.

Question 18

where are nerves

Answer 18

largely a PSN structure with essentially no nerves in the CNS

Question 19

structures that make up a nerve

Answer 19

the axons of many neurons, often myelin sheaths, connective tissue sheaths that bind the axons together, blood vessels
considered an organ

Question 20

electrical signals

Answer 20

specialis channels help establish a difference in electrical and ionic balance inside and outside the cell. this allows it to become electrically excitable.

Question 21

electrical charge measured in

Answer 21

millivolts (+/-)

Question 22

resting membrane potential

Answer 22

the imbalance of ions across their membranes at rest - more sodium outside and more potassium inside the cell

Question 23

factors influencing RMP

Answer 23

ion permeability - how easily an ion can pass across the membrane
ion concentration - how much an ion is present
ion equilibrium potential - balance

Question 24

graded potentials

Answer 24

variable in size occurring in the neuronal cell body. these potentials require the channels in the membrane to open/close from the resting state

Question 25

gated channels

Answer 25

control ion permeability into and out of the neuron

Question 26

important types of gated channels opened by neurotransmitters

Answer 26

chemically gated and voltage gated

Question 27

action potentials (AP)

Answer 27

a graded potential thats reached the threshold fires an action potential at the axon hillock

Question 28

phases of an action potential

Answer 28

1

Question 29

propagation of AP's

Answer 29

AP means that the AP is traveling along the axon due to the positive charge spreading along adjacent sections of an axon by local current flow

Question 30

local current flow

Answer 30

Couse new sections of the membrane to depolarise as the AP starts in one area the depolarizing spreads out and triggers an action potential in the next area

Question 31

factors that effect how quickly the AP travels

Answer 31

- how big the axon is and the resistance of the axon membrane to ion leakage

Question 32

axons

Answer 32

axons can have sections of myelination with small gaps called nodes of ranvier that are unmyelinated

Question 33

movement down an axon

Answer 33

myelinated axons potentials occur by hopping from one node to another called saltatory conduction as it increases the AP speed.

Question 34

synapses

Answer 34

site where two neurons communicate with each other using neurotransmitters as chemical messengers. presynaptic to postsynaptic

Question 35

space or gap between neurons

Answer 35

synaptic cleft chemical signal chemical synapse

Question 36

parts of a synapse

Answer 36

the presynaptic axon terminal, the synaptic vesicles, voltage gated Ca2+ channels, synaptic cleft, neurotransmitter receptors

Question 37

events at the synapse

Answer 37

1. the action potential arrives at the axon terminal and depolarizes 2. this opens the Ca2+ channels Ca2+ enters the presynaptic terminal 3. synaptic vesicles dock and fuse with the presynaptic membrane and releases neurotransmitters 4. neurotransmitters crosses the synaptic cleft and actives receptors on the post S membrane 5. this generates a EPSP if big enough at trigger zone