The nervous system functioning Chapter 2

Question 1

The central NS consists of:

Answer 1

Brain and spinal cord

Question 2

The Peripheral NS consists of:

Answer 2

Autonomic and somatic NS

Question 3

The autonomic NS consists of:

Answer 3

Sympathetic and parasympathetic

Question 4

Function of the CNS

Answer 4

-CNS receives and interprets sensory information sent from the PNS
-Transmits motor messages to the PNS

Question 5

Function of the PNS

Answer 5

-The PNS transmits sensory information to the CNS
-Transmits motor messages from the spinal cord to appropriate body parts.

Question 6

Brain

Answer 6

Coordinates all the nervous system activities

Question 7

Spinal cord

Answer 7

-Receives sensory information from the PNS and transmits motor messages from the brain to the PNS.
-Responsible for the spinal Reflex.

Question 8

Somatic NS

Answer 8

• Transmits sensory information inwards towards the spinal cord.
• Transmits motor messages outwards from the spinal cord to the appropriate body parts
• Controls voluntary movements via its control of the skeletal muscles.

Question 9

Autonomic NS

Answer 9

• Regulates internal bodily functions.
• Controls involuntary activity of internal muscles and glands.
  -BRANCHES: sympathetic and para sympathetic

Question 10

Sympathetic NS

Answer 10

• Automatically energises and arouses the body during times of stress or need for increased physical activity.
• Activation triggers the fight-or-flight response.

Question 11

Parasympathetic NS

Answer 11

Calms the body and returns internal system to normal levels of activity when the stressor or need for increased physical activity disappears.

Question 12

neuron

Answer 12

A neuron is an individual nerve cell. The entire nervous system is comprised of neurons, organised into complex chains and networks that form neural pathways.

Question 13

structure and function of a neuron

Answer 13

-dendrites
-soma
-axon
-myelin sheath
-Nodes of Ranvier
-axon terminals
-Neurotransmitters

Question 14

Dendrites

Answer 14

Branch-like extensions of the neuron that receives (chemical) information from the other neurons and transmits it to the soma

Question 15

Soma

Answer 15

The cell body that transfers information from the Dendrites to the Axon. The Soma also contains the nucleus, which keeps the neuron functioning.

Question 16

axon

Answer 16

A long tube-like structure that transmits (electrical) information away from the Soma and to the next neuron in the neural pathway.

Question 17

myelin sheath

Answer 17

A white, fatty substance that coats the Axon. insulating it and preventing the information from leaving the neuron too early. It also speeds up the neural transmission.

Question 18

Nodes of Ranvier

Answer 18

the gaps formed between the myelin sheath where the axons are left uncovered. Because the myelin sheath is largely composed of an insulating fatty substance, the nodes of Ranvier allow the generation of a fast electrical impulse along the axon

Question 19

Axon terminals

Answer 19

Branches extend out from the axon and end in knob-like structures called terminal buttons. Each terminal button contains chemicals called neurotransmitters that transmit the information from the Axon to the next neuron in the neural pathway

Question 20

Neurotransmitters

Answer 20

The chemical form of a neural message is known as a neurotransmitter.
-a signalling molecule secreted by a neuron to affect another cell across a synapse.

Question 21

Efferent

Answer 21

motor neurons: the nerve fibres responsible for carrying signals from the brain to the peripheral nervous system in order to initiate an action.

Question 22

afferent

Answer 22

sensory neurons: the nerve fibres responsible for bringing sensory information from the outside world into the brain

Question 23

Motor neurons

Answer 23

• Sends information AWAY from the CNS to muscles, organs and glands.
• Enable movements in the body via muscles, organs and glands.

Question 24

sensory neurons

Answer 24

Sends information from sensory receptors (e.g. in skin, eyes, nose, tongue, ears) TOWARDS the CNS

Question 25

Interneurons (relay)

Answer 25

- Sends information **BETWEEN** sensory neurons and motor neurons - Transmits sensory information to the brain and motor messages from the brain to the body - Act as a link between CNS and PNS - Located in the spinal cord

Question 26

Synaptic transmission

Answer 26

-process by which one neuron communicates with another -Information is passed down the axon as an electrical impulse (action potential) - crosses over the synaptic gap between the presynaptic neuron and post-synaptic neuron - At the end of the neuron (in the axon terminal) are the synaptic vesicles, which contain chemical messengers (neurotransmitters) -When the electrical impulse (action potential) reaches these synaptic vesicles, they release their contents of neurotransmitters. -Neurotransmitters then carry the signal across the synaptic gap. - They bind to receptor sites on the post-synaptic cell

Question 27

Spinal reflex

Answer 27

1. Sensory neurons detect the stimuli and send the information to the spinal cord. 2. The interneurons in the spinal cord receive the sensory information and connect with the motor neurons to initiate a response. 3. The motor neurons carry the response back to the appropriate body part 4. The reflex action occurs 5. While the reflex is occurring the sensory information has travelled from the spinal cord to the brain for processing and the sensation is then “felt.”

Question 28

excitatory effect

Answer 28

consequently stimulate or activate postsynaptic neurons to perform their functions -Glutamate

Question 29

inhibitory effect

Answer 29

block and prevent postsynaptic neurons from firing -GABA

Question 30

Glutamate (Glu)

Answer 30

-Excitatory neurotransmitter -Increases the likelihood of the postsynaptic neuron firing an action potential -strongly associated with enhanced learning and memory -too little or too less can result in damage due to overstimulation

Question 31

GABA (gamma-aminobutyric acid)

Answer 31

-Inhibitory neurotransmitter -Decreases the likelihood of the postsynaptic neuron firing an action potential -maintains neurotransmission at an optimal level -low levels cause seizures and anxiety

Question 32

neuromodulators

Answer 32

a chemical molecule that has an effect on multiple postsynaptic neurons -involved in enhancing signal transmission -chemical and released in the same way as neurotransmitters -Dopamine, serotonin

Question 33

Dopamine

Answer 33

-drive, motivation, motor movement -neuromodulator -addictive behaviours -reward base learning -substantia nigra, ventral tegmental area -excitatory and inhibitory effects on the postsynaptic neuron -coordinating voluntary motor movements

Question 34

serotonin

Answer 34

-mood stabiliser -digestion and metabolism -lack of serotonin: mental health issues -raphe nuclei -inhibitory effect on post synaptic neuron -sleep-wake cycle

Question 35

neural plasticity

Answer 35

the ability of the brains neural structure or functions to be changed by experience throughout the life span

Question 36

Sprouting

Answer 36

-ability of dendrites or axons to develop new extensions -increases formation of synaptic connections

Question 37

rerouting

Answer 37

the ability of a neuron that is connected to a damaged neuron to create an alternative synaptic connection with an undamaged neuron

Question 38

coactivated

Answer 38

the activation of the same response at the same time by two different stimuli.

Question 39

synaptic plasticity

Answer 39

the ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity.

Question 40

long term potentiation

Answer 40

long lasting and experience dependent strengthening of synaptic connections in response to frequent and repeated use during learning and memory

Question 41

increased synaptic connections involves:

Answer 41

increased number of receptor sights on dendrites, bushier dendrites

Question 42

Long term depression

Answer 42

the long-lasting and experience-dependent weakening of synaptic connections between neurons that are not regularly coactivated

Question 43

decreased synaptic connections is a result of:

Answer 43

neural pathways that have been previously established during learning and memory are no longer regularly activated