15.1 neurones and nervous coordination

Question 1

what are the 2 main forms of coordination in animal

Answer 1

• the nervous system
• the hormonal system

Question 2

what does the nervous system do

Answer 2

• uses nerve cells to pass electrical impulses along their length
• stimulate their target cells by secreting neurotransmitters
• responses are short lived, rapid and localised to a specific area

Question 3

what is an example of the nervous coordination

Answer 3

• the reflex arch
• short lived, rapid and restricted to one region if the body

Question 4

how does the hormonal system work

Answer 4

• produces hormones that are transported in the blood plasma to their target cell
• target cells have specific receptors on their cell surface membrane which is stimulated by changes to hormone concentration
• slower, less specific, long lasting and widespread

Question 5

what is an example of hormonal coordiantion

Answer 5

• control of blood glucose concentration
• slower long term widespread effect

Question 6

what is a neuron

Answer 6

• specialised cells adapted to rapidly carrying nerve impulses form one part of the body to another

Question 7

what is motor neuron made up of

Answer 7

• cell body
• dendrons
• axons
• schwann cells
• myelin sheath
• nodes of ranvier

Question 8

what is a motor neurons cell body

Answer 8

• has a nucleus and large amounts rough endoplasmic reticulum
• produces proteins and neurotransmitters

Question 9

what are dendrons

Answer 9

• extensions of the cell body
• subdivides into dendrites
• carry nerve impulses towards the cell body

Question 10

what are axons

Answer 10

• single long fibre
• carries nerve impulses away from the cell body

Question 11

what are schwann cells

Answer 11

• surround the axon, protecting it and providing electrical insulation
• carry out phagocytosis
• play a part in nerve regeneration

Question 12

what are mylin sheath

Answer 12

• made up of schwann cells so covers the axon

Question 13

what are nodes of ranvier

Answer 13

• constrictions between adjacent schwann cells where there is no mylin sheaths
• constrictions are 2-3 um long and occur every 1-3 mm

Question 14

what are sensory nuerones

Answer 14

• transmit nerve impulses form a receptor to a motor neurone
• long dendron and short axon

Question 15

what are motor neurons

Answer 15

• transmit nerve impulses form a relay neuron to an effector (glands and muscle)
• long axon and short dendrites

Question 16

what are relay nueron

Answer 16

• transmit impulses between nuerones
• short dendrites short axons