Nervous system, neurons, synapses

Question 1

2 Main functions of nervous system

Answer 1

To collect, process and respond to info in the environment.

To coordinate the working of different organs and cells in the body.

Question 2

Define Nervous system

Answer 2

A specialised network of cells in the human body. it is our primary internal communications system based on electrical and chemical signal

Question 3

Structure of the nervous system

Answer 3

Central nervous system - brain and spinal chord (a bundle of nerves which connects nearly all parts of the body to the brain)

Peripheral - All other nerves

Question 4

1. Divisions of peripheral

Answer 4

Peripheral - Transmits messages via neurons to and from the CNS

Question 5

2. Somatic

Answer 5

Controls muscle movements and recieves information from the sensory receptor.
Voluntary control over skeleton and muscles.
Carries commands from motor cortex (controlled from) and has sensory and motor pathways

Question 6

2. Autonomic

Answer 6

Vital functions like breathing, stress and heart rate.
automatic/involuntary control.
controlled by brain stem and only has motor neuron pathways.

Question 7

3. Sympathetic

Answer 7

Stimulates functions like digestion, gets ready for action

Question 8

3. Parasympathetic

Answer 8

Slows functions like digestion involved in ‘rest and digest’ calms down.

Question 9

Homeostasis

Answer 9

The two systems SYMP and PARA interact to create homeostasis. their actions are mostly antagonostic, work in opposition to eachother. a normal balance of both is called maintaining homeostasis.

Question 10

Definition of neuron

Answer 10

Cells that make up nervous system. Conduct electrical impulses which transmit messages around the body

Question 11

Dendrites

Answer 11

Recieve signals from other neurons or from sensory receptor cells. Dendrites connected to cell body which contains the nucleus.

Question 12

Axon

Answer 12

The axon is a long slender fibre tht carries nerve impulses in the form of an electrical signal (action potential). Most are sourrounded by a myelin sheath (except for relay) insulating neuron for a faster impulse.

Question 13

Node of ranvier

Answer 13

A node of ranvier is a periodic gap in sheath that make the electrical impulses jump quicker as the consistency of them increases conduction velocity

Question 14

Schwann cell

Answer 14

Schwann cells wrap its plasma membrane concentrically around the axon and form the myelin to form the myelin sheath

Question 15

Axon terminal

Answer 15

Make synaptic connections with another neuron. Triggers movement of vesicles towards membrane.

Question 16

Action potential

Answer 16

How information is transmitted within the neuron.
The dendrites of the neuron recieve information from sensory receptors or other neurons. This excites the neurons causing sodium ions to enter the membrane. This information is carried in vesicles and passed down to the cell body and onto the axon. Once info arrives at axon, it travles down its length in electrical signal known as action potential.

Question 17

Types of neuron - Relay

Answer 17

Between sensory and motor. located in brain and spinal chord. (interneuron) allows sensory and motor to communicate. Short dendrite short axon

Question 18

Types of neuron - Sensory

Answer 18

From sensory register to CNS. In Peripheral NS. Goes towards brain. Sends signal from senses to CNS. Dendrite long axon short

Question 19

Types of neuron - Motor

Answer 19

From CNS to effector to promote movement. Located in cell body of motor neuron and part of the peripheral. Denderite short. Axon Long.

Question 20

Types of neuron - Motor

Answer 20

From CNS to effector to promote movement. Located in cell body of motor neuron and part of the peripheral. Denderite short. Axon Long.

Question 21

Transmission of neuron

Answer 21

1. receptors in the skin detect a stimulus
2. sensor neuron sends electrical impulses to a relay neuron which is located in the spinal chord of the CNS
3. motor neuron sends electrical impulses to effector
4. effector produces a response

Question 22

Synaptic Transmission

Answer 22

neurons communicate with each other within groups known as neural networks. Each neuron is seperated from the next by a tiny gap called the synapse.
Signals within neurons are transmitted electrically. Signals between neuron are transmitted chemically across the synapse. These chemical messengers are known as neurotransmitters.

Question 23

Synaptic Transmission

Answer 23

neurons communicate with each other within groups known as neural networks. Each neuron is seperated from the next by a tiny gap called the synapse.
Signals within neurons are transmitted electrically. Signals between neuron are transmitted chemically across the synapse. These chemical messengers are known as neurotransmitters.

Question 24

Ex of neurotransmitters

Answer 24

Serotonin - mood, sleep, eating
Dopamine - motivation, movement, attention, learning
GABA - little linked to anxiety disorders
Noradrenaline - associated with fight or flight, Sz

Question 25

Process of synaptic transmission

Answer 25

1. an electrical impulse travels along the axon of the pre synaptic neuron
2. triggers nerve endings of pre synaptic neuron to release chemical messengers ‘neuro transmitters’ from vesicle
3. these diffuse across synapse and bind with receptor molecules on the membrane of the post synaptic neuron
4. the receptor molecules on the post bind only to the specific chemicals released from the first neuron. This stimulates second neuron to transmit electrical impulse
5. Reuptake. neurotransmitters re absorbed in vesicles of pre synaptic neuron after performing function of transmitting a neural impulse

Question 26

Why neurons only travel in one direction

Answer 26

The direction of transmission can only be one way because the neurotransmitter released from synaptic terminal are recieved by post synaptic neuron

Question 27

Process of EPSP and IPSP

Answer 27

A receptor neuron can recieve both EPSP and IPSP at the same time. The likleyhood of the cell firing is therefore determined by adding up all of the excitatory and inhibitory synaptic input. The result of this calculation is known as summation. Determines whether a cell fires.

Question 28

EPSP

Answer 28

Excitatory post synaptic potential. Neurotransmitter is adrenaline. Positive charge produced. Increases likleyhood neuron firing.

Question 29

IPSP

Answer 29

Inhibitory post synaptic potential. Neurotransmitter is Serotonin. Negative charge produced. Decrease likleyhood of neuron firing. Calming effect.

Question 30

Neurotransmitter

Answer 30

CHemical that diffuses across synapse to next neuron.