The Nervous system

Question 1

What is the nervous system?

Answer 1

Consists of the central nervous system and the peripheral nervous system.

Question 2

What is the central nervous system?

Answer 2

Consists of the brain and spinal cord and is the origin of all complex commands and decisions

Question 3

Whats the Peripheral nervous system?

Answer 3

Sends information to the central nervous system (CNS) from the
outside world, and transmits messages from the CNS to muscles and glands in the body.

Question 4

Whats the Somatic nervous system?

Answer 4

• Transmits information from receptor cells in the sense organs to the central nervous system (CNS).
• It also receives information from the CNS that directs muscles to act.

Question 5

Whats the Autonomic nervous system?

Answer 5

Transmits information to and from internal bodily organs. It is
‘autonomic’ as the system operates involuntarily (i.e. it is automatic). It has two main divisions: the
sympathetic and parasympathetic nervous systems.

Question 6

What are the differences between the somatic and autominic nervous system?

Answer 6

Sensory:
-Has sensory and motor pathways
- Controls skeletal and muscle movement
-Mostly concious

Automnic:
-Just sensory pathways
- Controls internal organs and glands
-Unconcious

Question 7

Whats a neuron?

Answer 7

The basic building blocks of the nervous system, neurons are nerve cells that process and
transmit messages through electrical and chemical signals.

Question 8

Do all sensory neurons reach the brain?

Answer 8

Not all sensory neurons reach the brain, as some neurons stop at the spinal cord, allowing for quick
reflex actions.

Question 9

Describe sensory neurons

Answer 9

From receptors (e.g. eyes, ears, tongue and skin) to the CNS (brain or spinal cord)

Question 10

Describe motor neurons

Answer 10

From CNS to effectors (muscles and glands)

Question 11

Describe relay neurons

Answer 11

Found in the central nervous system (brain and spinal cord)

Question 12

What are dendrites?

Answer 12

Receive signals from other neurons or sensory receptor cells

Question 13

Whats the cell body?

Answer 13

‘Control centre’ which contains the nucleus

Question 14

Whats the axon?

Answer 14

Long slender fibre that carries electrical impulses (also known as action potentials)

Question 15

Whats the myelin sheath?

Answer 15

Insulates the neuron so that electrical impulses travel faster (but not in relay neurons)

Question 16

Whats the axon terminal?

Answer 16

The end of the neuron that connects to other neurons or organs

Question 17

What does synaptic transmission mean?

Answer 17

The process by which neighbouring neurons communicate with each other by sending chemical messages across the gap (the synaptic cleft) that separates them

Question 18

Whats a neurotransmitter?

Answer 18

Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another. Neurotransmitters can be broadly divided into excitatory and inhibitory

Question 19

Whats exictation?

Answer 19

When a neurotransmitter (e.g. adrenaline) makes the postsynaptic neuron more likely to fire by increasing the positive charge of the neuron.

Question 20

Whats inhibtion?

Answer 20

When a neurotransmitter (e.g. serotonin) makes the postsynaptic neuron less likely to fire by decreasing the charge of the neuron.

Question 21

Whats summation?

Answer 21

-The combined effect of the excitation and inhibition. -If the net total on the postsynaptic neuron passes the threshold (-55mV) then the postsynaptic neuron will fire.

Question 22

Describe the process of synaptic transmission

Answer 22

1. Electrical impulses (action potentials) reach the presynaptic terminal
2. Electrical impulses (action potentials) trigger release of neurotransmitters, such as serotonin
3. Neurotransmitters diffuse across the synaptic cleft
4. Neurotransmitters combine with receptors on the postsynaptic membrane
5. Stimulation of postsynaptic receptors by neurotransmitters result in either excitation
   (depolarisation) or inhibition (hyperpolarisation) of the postsynaptic membrane.

Question 23

Why can neurons only transmit information in one direction at a synapse?

Answer 23

-The synaptic vesicles containing the neurotransmitter are only present on / released from the presynaptic membrane

-The receptors for the neurotransmitters are only present on the postsynaptic membrane

-Diffusion of the neurotransmitters means they can only go from high to low concentration so can only travel from the presynaptic to the postsynaptic membrane.

Question 24

Describe Seretonin

Answer 24

• It is believed to help regulate mood and social behaviour, appetite and digestion, sleep, memory, and sexual desire and function. Low levels of serotonin are linked to depression

Question 25

Describe Dopamine

Answer 25

-Affects your emotions, movements and your sensations of pleasure and pain. -Depleted levels are linked to Parkinson’s disease. An excess of DA receptors is linked to schizophrenia.

Question 26

Describe Neuropinephrine

Answer 26

-Important for attentiveness, emotions, sleeping, dreaming, and learning. -Norepinephrine is also released as a hormone into the blood, where it causes blood vessels to contract and heart rate to increase. Norepinephrine plays a role in mood disorders such as manic depression.