Neuronal Communication

Question 1

Define the nervous system

Answer 1

Electrical impulses which move through the CNS

Question 2

Define the endocrine system

Answer 2

Release of hormones into blood

Question 3

What are the 3 types of neurone?

Answer 3

Sensory
Motor
Relay

Question 4

What is the role of aa Sensory receptor?

Answer 4

To detect stimuli and convert it into an electrical impulse

Question 5

Why can receptors also be called a transducer?

Answer 5

Creates electrical signals

Question 6

Name some features of Sensory neurones

Answer 6

Short axons
Long dendrites

Question 7

What is the role of a motor neurone?

Answer 7

Create an electrical impulse from CNS to effectors in the muscles

Question 8

Define homeostasis

Answer 8

Co ordination of organs to maintain optimum conditions needed to function

Question 9

What is cell to cell signalling?

Answer 9

When a cell releases a chemical causing a change to another target cell

Question 10

Name an example of co ordination I plants

Answer 10

Growing towards the light to maximise photosynthesis

Question 11

Define a Sensory receptor

Answer 11

Cell which detects stimuli at receptors and turn into electrical impulse

Question 12

Define a transducer

Answer 12

Changes a signal into another form

Question 13

Name some properties of a pacinian corpuscles

Answer 13

Respond to pressure changes
Deep in skin
Wrapped in layers of tissue sperated by gel
Have channel proteins in membrane

Question 14

Define a nerve impulse

Answer 14

Transmitted as an electrical impulse caused by movement of Na+ and K+ ions

Question 15

Outline how ione move across the membrane

Answer 15

Ions move through gated channel proteins which cause a change in potential difference

Question 16

What are the 2 pumps used in neurone membranes?

Answer 16

Na+ and K+ pump using ATP moves 3 Na+ ions out and 2 K+ ions in membrane

Voltage sensitive Channels open and close depending on voltage. Cytoplasm contains negatively charged ions

Question 17

What does polarised mean?

Answer 17

Inside I cell is more negative than outside

Question 18

What does depolarised mean?

Answer 18

Negative to positive

Question 19

What does repolarised mean?

Answer 19

Positive to negative

Question 20

What is propagation?

Answer 20

Current that reaches threshold potential

Question 21

Outline an action potential

Answer 21

Neuron is polarised
Na ions move out
Action potential is reached
K ions move in
Hyperpolarisation occurs

Question 22

How is a strong or weak stimulus identified?

Answer 22

Frequency of action potentials

Question 23

What is the equation and unit for frequenc?

Answer 23

1 ÷ time (Hz)

Question 24

How many milli seconds in one second?

Answer 24

1000

Question 25

Where does diffusion of ions occur in a myelinated neurone?

Answer 25

Knodes of ranvier

Question 26

What stops an action potential from going backwards?

Answer 26

Voltage gated calcium ions

Question 27

What is the role of excitatory neurotransmitters?

Answer 27

Depolarise post synaptic neurone and creates an action potential if the threshold is met

Question 28

What is the role of inhibitory neurotransmitters?

Answer 28

Hyperpolarisation to prevent action potential

Question 29

Outline acetylcholine synaptic transmission

Answer 29

1. Action potential causes calcium channels to open
2. Vesicle binds to membrane to release acetylcholine in the synapse
3. Acetylcholine docks and sodium channels to open. Sodium moves down steep concentration gradient
4. New action potential
5. Acetylcholine diffuses back preventing continuous action potential
6. Ethanoic acid and choline form acetylcholine

Question 30

Define temporal summation

Answer 30

Impulses arrive in quick succession causing action potential

Question 31

Define spatial summation

Answer 31

Impulses arrive at many Synapses generating an action potential

Question 32

What is grey matter?

Answer 32

Unmyelinated neurones