nervous system/reflexes

Question 1

cell body

Answer 1

contains the nucleus and organelles of the cell to control the normal function

Question 2

dendrites

Answer 2

short and branched extension of the neuron that receives impulses and directs them towards the cell body

Question 3

axon

Answer 3

thin extension of the neuron that usually conducts impulses away from cell body, can be covered by myelin sheath

Question 4

myelin sheath

Answer 4

fatty insulate layer, formed by Schwann cells, which can surround a dendrite or axon and functions to increase speed of a nerve impulse

Question 5

nodes of ranvier

Answer 5

gaps between the myelin sheath that forces impulses to travel from node to node

Question 6

axon terminal

Answer 6

small knobs on the ends of anions that contain neurotransmitter chemicals that are released when nerve impulses arrive there

Question 7

multi-polar neuron

Answer 7

one axon
multiple dendrites
most likely to be interneuron

Question 8

bi-polar neuron

Answer 8

one axon
one dendrite
eyes/ear/nose

Question 9

uni-polar neuron

Answer 9

one extension
cell. body is to the side
usually sensory

Question 10

reflexes

Answer 10

a rapid and involuntary response to a stimulus

Question 11

three features of reflexes

Answer 11

rapid, involuntary, stereotyped (same neutrons every time, reflex arc)

Question 12

innate/learned reflexes

Answer 12

innate; born knowing how to do

learned; become involuntary after lots of practise

Question 13

5 steps for reflex arc

Answer 13

1. receptor
2. sensory neuron
3. interneuron in spinal cord
4. motor neuron
5. Effector

Question 14

nerve impulses

Answer 14

electrochemical change that travels along nerve fibre
-change in electrical voltage caused by change in concentrations of ions inside and outside of cell membrane of neuron
speed is determined by diameter and myelination