CH2

Question 1

What is the central nervous system?
What does the CNS include?
Define those parts/state their function.

Answer 1

Central Nervous System – A divison of the nervous system that is made up of the spinal cord and the brain. It recieves sensory information from the peripheral nervous system. It sends motor information to the peripheral nervous system.
- Brain – Complex organ that coordinates mental processes and behaviour and regulates bodily activity.
- Spinal Cord – Cable of nerve tissue that extends from the brain, connecting it to the peripheral nervous system. It is composed of afferent tracts which transmit sensory messages from the PNS to the brain and efferent tracts which transmit motor messages from the brain to the PNS.

Question 2

Define the Peripheral Nervous System.

Answer 2

Peripheral Nervous System:
a major division of the nervous system comprising every neuron in the body outside the central nervous system. It controls the muscles, organs, and glands. (MOG (acronym))

Question 3

List the sub-sections of the PNS

Answer 3

Automatic and Somatic Nervous System

Question 4

What is the difference between Sensory and Motor Neural Pathways?

Answer 4

Sensory Neural Pathways – Pathways made up of sensory neurons.
Motor Neural Pathways – Pathways made up of motor neurons.

Question 5

What are skeletal Muscles?
What are Visceral Muscles, Organs and Glands?

Answer 5

Skeletal Muscles - muscles connected to the skeleton that carry out voluntary motor movements.
Visceral Muscles, Organs and Glands – muscles, organs, and glands not connected to the skeleton that are predominantly self-regulating and do not require conscious control.

Question 6

What is the somatic nervous system?

Answer 6

Somatic Nervous System – a division of the peripheral nervous system that transmits neural messages related to voluntary motor movement.

Question 7

What is the autonomic nervous system?

Answer 7

Automatic Nervous System – a division of the peripheral nervous system that regulates visceral muscles, organs, and glands, and transmits neural messages to the central nervous system about their activity.

Question 8

Identify and Define the parts of the ANS

Answer 8

Sympathetic Nervous System - a division of the autonomic nervous system that increases activity of the visceral muscles, organs, and glands, to prepare the body to respond to a threat or stressor.
Parasympathetic Nervous System - a division of the autonomic nervous system that maintains optimal and balanced functioning by decreasing the activity of visceral muscles, organs, and glands.
Enteric Nervous System - a division of the autonomic nervous system that is dedicated to the functioning of the digestive tract. This network of nerves enables bidirectional communication between the brain and the gut.

Question 9

Define a neuron.
List and describe the three types of neurons.

Answer 9

Neuron – a nerve cell that receives and transmits neural information.
Motor/Efferent Neurons – neurons that transmit neural messages about motor movement from the central nervous system to the peripheral nervous system.
Sensory/Afferent Neurons – neurons that transmit neural messages about bodily sensations from the peripheral nervous system to the central nervous system.
Interneurons – neurons that transfer neural messages between sensory neurons and motor neurons.

Question 10

What is a conscious response?

Answer 10

Conscious response - a deliberate and voluntary action that is initiated by the brain and performed intentionally by the body.

Question 11

Describe all the steps in a conscious response

Answer 11

Steps:
1. Sensory stimuli come in contact to sensory receptors.
2. The sensory neural message is transmitted to the brain via afferent pathways in the somatic nervous system and then the spinal cord.
3. The brain processes the information and initiates a conscious motor response.
4. The motor neural message is transmitted to skeletal muscles via efferent pathways in the spinal cord, and then the somatic nervous system.
5. Skeletal Muscles carry out the conscious motor response to the sensory stimuli.

Question 12

What is a sensory receptor?

Answer 12

Sensory receptor - a nerve ending that detects internal sensations in the body and external sensations from the environment.

Question 13

What is an unconscious response?

Answer 13

Unconscious response - an automatic and involuntary action that is performed by the body independently of the brain.

Question 14

What is a spinal reflex?
What is a reflex arc?

Answer 14

Spinal Reflex - an unconscious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain.
Reflex arc - the path along which the neural signal is transmitted as part of the spinal reflex.

Question 15

Describe all the steps of a spinal reflex.

Answer 15

Steps:
1. Dangerous or harmful sensory stimuli is detected by sensory receptors. This is then transmitted via sensory neurons in the somatic nervous system to the spinal cord.
2. Interneuron in spinal cord relays the neural signal to a motor neuron initiating an automatic and unconscious response.
3. The motor message is transmitted via motor neurons to the skeletal muscles to carry out action.
4. The sensory message travels via afferent tracts to the brain. The brain the independently processes the sensation.

Question 16

List at least 3 responses of the sympathetic nervous system.

Answer 16

Sympathetic nervous system:
- Heart rate increases to increase blood flow, enabling high levels of physical activity.
- Breathing rate increases and lung airways expand to increase oxygenation, enabling high levels of physical activity.
- Pupils dilate to allow more light to enter the eyes, improving vision.
- Adrenal glands secrete stress hormones, such as adrenaline, to energise the body.
- Sweat glands are activated, increasing perspiration.
- Digestion is inhibited to conserve energy required for high levels of physical activity.
- The bladder relaxes to conserve energy, enabling this energy to be directed to other bodily processes that need it more during high levels of physical activity.
- The body releases more glucose to energise the body.

Question 17

List at least 3 responses of the parasympathetic nervous system.

Answer 17

Parasympathetic nervous system:
- The heart beats at a steady and regular rate that supports optimal and balanced functioning.
- Lung airways constrict, enabling a steady and regular breathing rate.
- Pupils constrict according to external light levels, allowing an appropriate amount of light to enter the eyes for adequate vision.
- Adrenal glands do not secrete stress hormones, such as adrenaline, to allow the body to rest.
- Sweat glands are regulated, controlling perspiration.
- Digestion occurs normally, enabling food to be metabolised by the body.
- The bladder constricts and urination is controlled.
- The body releases less glucose to allow the body to rest and prevent the depletion of energy stores.

Question 18

What is a receptor site?

Answer 18

Receptor site - a protein molecule on the dendrites of a neuron that receives neurochemicals.

Question 19

What is a neural synapse?

Answer 19

Neural synapse - the region that includes the axon terminals of the presynaptic neuron, the synaptic gap, and the dendrites of the postsynaptic neuron.

Question 20

What is a neurochemical?

Answer 20

Neurochemical - a chemical substance that transmits neural information within the nervous system.

Question 21

What is a presynaptic neuron and what is a postsynaptic neuron?

Answer 21

Presynaptic neuron - the neuron that releases neurochemicals into the neural synapse Axon terminal (also known as a terminal button) the end of a neuron that releases neurochemicals into the neural synapse.
Postsynaptic neuron - the neuron that receives neurochemicals from the neural synapse.

Question 22

What is a dendrite? what is a synaptic gap?

Answer 22

Synaptic gap - the space between the presynaptic neuron and the postsynaptic neuron.
Dendrite - branched extensions of a neuron on which receptor sites are located.

Question 23

List the key parts of a neuron and their functions.

Answer 23

Dendrite: Receives incoming neural messages.
Soma: The body of the neuron, containing the nucleus.
Axon: The pathway which the messages travel on.
Myelin Sheath: Fatty tissue that encase the axon to aid in speed of transmission by providing insulation. (Gaps are called nodes of Ranvier.)
Axon Terminals: Exit pathways to the next neuron.
Terminal Buttons/Synaptic Knobs: Releases a chemical substance (neurotransmitter) to receiving neuron for communication.

Question 24

What is synaptic transmission?

Answer 24

Synaptic transmission - the chemical conveyance of neural information between two neurons across a neural synapse.

Question 25

Describe all the steps in the synaptic transmission.

Answer 25

Synaptic Transmission Process:
1. Neurochemicals are produced in the axon terminals of the presynaptic neuron.
2. Neurochemicals are released from the axon terminals of the presynaptic neuron into the synaptic gap.
3. Neurochemicals bind to receptor sites on the dendrites of the postsynaptic neuron.
4. Neurochemicals affect the postsynaptic neuron, either triggering or inhibiting a response.

Question 26

What is Neurotransmission?

Answer 26

Neurotransmission – Process of communication between neurons using electrochemical energy.

Question 27

What is action potential and what charge/potential do certain neurons have?

Answer 27

Action potential - an electrical impulse that travels down the axon of a neuron.
Neurons that are not activated have a resting potential and are negatively charged.
Neurons that are initiated have an action potential and is positively charged.

Question 28

what is a neurotransmitter, what are the two main types and where is it stored?

Answer 28

• Neurotransmitter - a chemical molecule that has an effect on one or two postsynaptic neurons.
• Excitatory and Inhibitory Neurotransmitters
• Stored in synaptic vesicles.

Question 29

Define Excitatory Effect.

Answer 29

Excitatory Effect - when the neurotransmitter increases the likelihood of the postsynaptic neuron firing an action potential.

Question 30

Define a type of excitatory neurotransmitter and its role in functioning.

Answer 30

Glutamate - the main excitatory neurotransmitter in the nervous system.
Role in Functioning:
* Enables synaptic plasticity.
* Strengthens synaptic connections.
* Important role in learning and memory.

Question 31

Define Inhibitory Effect.

Answer 31

Inhibitory Effect - when the neurotransmitter decreases the likelihood of the postsynaptic neuron firing an action potential.

Question 32

Define a type of Inhibitory neurotransmitter and its role in functioning.

Answer 32

Gamma-Aminobutyric Acid (GABA) - the main inhibitory neurotransmitter in the nervous system
Role in Functioning:
* Prevents overexcitation of neurons.
* Reduces anxiety.
* Important role in preventing seizures.

Question 33

What is a neuromodulator and what is it involved in

Answer 33

• Neuromodulator - a chemical molecule that has an effect on multiple postsynaptic neurons.
• Their effects are relatively long lasting compared to neurotransmitters.
• Involved in enhancing responsiveness of receptor sites and the excitatory and inhibitory effects of neurotransmitters.
• Involved in changing the neurotransmitter release pattern of the presynaptic neuron.

Question 34

List two types of neuromodulators. (No definition)

Answer 34

Dopamine and Serotonin

Question 35

Define Dopamine

Answer 35

Dopamine - a neuromodulator primarily responsible for voluntary motor movement, the experience of pleasure, and reward-based learning.

Question 36

What is the effect of dopamine?

Answer 36

Either excitatory or inhibitory depending on the receptor sites present at the brain region.

Question 37

What are the two important roles that dopamine is involved in? What experience is dopamine associated with? What does dopamine influence?

Answer 37

• An important role in coordinating voluntary motor movement.
• An important role in reward-based learning.
• It is associated with the experience of pleasure.
• Influences motivation as behaviours with more dopamine released is more likely to be repeated.

Question 38

What regions in the brain produce dopamine?

Answer 38

The midbrain:
Substantia Nigra
Ventral Tegmental Area

Question 39

Define Serotonin

Answer 39

Serotonin - a neuromodulator primarily responsible for the regulation of mood and sleep.

Question 40

What is the effect of Serotonin?

Answer 40

Inhibitory Effects on postsynaptic neurons.

Question 41

What are the two important roles that Serotonin is involved in? What other roles can serotonin have? What factors this?

Answer 41

• An Important role in mood regulation and stabilisation.
• An Important role in regulating the sleep-wake cycle.
• Serotonin has various other roles depending on the receptor types it binds to and the brain area it acts upon, including appetite, digestion, and arousal.

Question 42

What region in the brain produces Serotonin?

Answer 42

Raphe Nuclei – masses of neurons in the brainstem.

Question 43

Neuroplasticity vs Synaptic Plasticity

Answer 43

Neuroplasticity – The ability of the brain to physically change in response to experience.
Synaptic Plasticity – the ability of synaptic connections to change over time in response to activity or experience.

Question 44

List the Mechanisms of Synaptic Plasticity. (No define)

Question 45

Define sprouting and describe its use.

Answer 45

Sprouting – the ability of dendrites or axons to develop new extensions or branches.
-This increases the reach of the neuron and enables the formation of new synaptic connections.

Question 46

Define pruning and describe its use.

Answer 46

Pruning – the elimination of synaptic connections that are not adequately activated.
- Necessary to accommodate stronger and more essential synaptic connections and to enhance the efficiency of brain functions.

Question 47

Define rerouting and describe how it happens.

Answer 47

Rerouting – the ability of a neuron that is connected to a damaged neuron to create an alternative synaptic connection with an undamaged neuron.
- The neuron abandons its synaptic connection with the damaged neuron and forms a new synaptic connection with an undamaged neuron.
- The synaptic connection is reestablished in a different route, restoring brain functioning.

Question 48

What are two ways that cause connections to change and what are they called?

Answer 48

Developmental Plasticity:
- Change in response to ageing and maturation.
Adaptive Plasticity:
- Change in response to brain trauma or injury.

Question 49

Learning vs Memory?

Answer 49

Learning – the process of acquiring knowledge, skills, or behaviours through experience.
Memory – the process of encoding, storing, and retrieving information that has been previously encountered.

Question 50

What is it called when synaptic connections are strengthened? Define that term and list three structural changes that occur.

Answer 50

Long-Term Potentiation – the long-lasting and experience-dependent strengthening of synaptic connections that are regularly coactivated.

Structural Changes:
- Increased number of receptor sites on postsynaptic neuron.
- Increased number of dendrites on postsynaptic neuron.
- Increased number of synaptic connections.

Question 51

What is it called when synaptic connections are weakened? Define that term and list three structural changes that occur.

Answer 51

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

Structural Changes:
- Decreased number of receptor sites on postsynaptic neuron.
- Decreased number of dendrites on postsynaptic neuron.
- Decreased number of synaptic connections.

Question 52

List the 5 stages of neural processes and give a general description - (May not need to know)

Answer 52

-Proliferation – Creating and enhancing neurons.
-Migration – The neurons move to certain areas.
-Circuit Formation – Synaptic connections are created.
-Circuit Pruning – Unnecessary connections are removed.
-Myelination – Strengthening the axon/connection (With myelin sheaths etc.)