Neurones

Question 1

what is a stimulus?

Answer 1

changes in the internal or external environments.

Question 2

what is a response?

Answer 2

when information is processed and movement occurs in response to a stimulus.

Question 3

what is the difference between hormone response and neuronal response?

Answer 3

neuronal response is quicker and more targetted.

Question 4

what is the role of neurones?

Answer 4

transmit electrical impulses rapidly around the body.

Question 5

what are the features of neurone structure?

Answer 5

• cell body
• axon
• dendrons

Question 6

what is the cell body?

Answer 6

contains the nucleus surrounded by cytoplasm. within cytoplasm there are large amounts of endoplasmic reticulum and mitochondria which are involved in the production of neurotransmitters.

Question 7

what are neurotransmitters?

Answer 7

chemicals which are used to pass signals from one neurone to the next.

Question 8

what are dendrons?

Answer 8

short extensions which come from cell body. These extensions divide into smaller and smaller branches called dendrites. They are responsible for transmitting electrical impulses towards the cell body.

Question 9

what are axons?

Answer 9

• singular elongated nerves.
• transmit impulses away from the cell body.
• fibre is cylindrical in shape consisting of a narrow region of cytoplasm surrounded by a plasma membrane.

Question 10

what are the different types of neurones?

Answer 10

• sensory neurone
• relay neurone
• motor neurone

Question 11

what is the role of sensory neurones?

Answer 11

transmit impulses from a sensory receptor to a relay neurone, motor neurone, or the brain.

Question 12

what is the structure of a sensory neurone?

Answer 12

• one dendron.
• one axon.

Question 13

what is the role of relay neurones?

Answer 13

transmit impulses between neurones.

Question 14

what is the structure of a relay neurone?

Answer 14

many short axons and dendrons.

Question 15

what is the role of motor neurones?

Answer 15

transmit impulses from relay neurones of sensory neurones to an effector.

Question 16

what is the structure of a mator neurone?

Answer 16

one long axon and many short dendrites.

Question 17

what are the two effectors?

Answer 17

• muscle
• gland.

Question 17

what are the two effectors?

Answer 17

• muscle
• gland.

Question 18

what are myelin sheath made up of?

Answer 18

many layers of plasma membranes.

Question 19

what produces the layers of plasma membranes in myelin sheath?

Answer 19

Schwann cells - by growing aroud the axon many times. Each time they grow around the axon, they lay down a double layer of phospholipid bilayer.

Question 20

what is the role of the myelin sheath?

Answer 20

acts as an insulating layer and allows mylinated neurones to conduct the electrical impulse at a much faster speed.

Question 21

what is the rate of transmission in myelinated neurones vs unmyelinated neurones?

Answer 21

myleniated neurones trasmit impulses at 100 metres per second. Unmylenatied neurones tranmist at 1 metre per second.

Question 22

where are nodes of ranvier found?

Answer 22

between each adjacent schwann cell.

Question 23

what does ms affect?

Answer 23

nerves in brain and spinal cord.

Question 24

what are the symptoms of ms?

Answer 24

problems with muscle movement, balance, and vision.