Nervous system

Question 1

1. Complete the following:

The nervous system is a ________________ of fibres which span the body co-ordinating a diverse range and voluntary and ________________ actions. It transmits ________________ between parts of the body. It responds rapidly to changes within the internal and external ________________ It works alongside the ________________ system to maintain ________________.

Answer 1

• A network of fibres which span the body, co-ordinating a diverse range of voluntary and involuntary actions.
• Transmits signals between parts of the body.
• Rapidly responds to changes within the internal and external environment.
• Works alongside the endocrine system to maintain homeostasis.

Question 2

1. Describe the difference between the central nervous system and the peripheral nervous system.

Answer 2

1. CNS: brain and spinal cord / PNS: Peripheral nerves (nerves not in the CNS)

Question 3

1. With regards to neuron function, complete the following table:

Processes sensory information, analyses, stores and makes decisions:

Detects internal and external environmental changes:

Produces a response to sensory information to effect change:

Answer 3

Function:

Processes sensory information….: INTEGRATION

Detects internal and external environmental changes: SENSORY

Produces a response to sensory information to effect change: MOTOR

Question 4

1. Complete the following diagram

Answer 4

Question 5

With regards to the effects of the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS), complete the following table:

Answer 5

Question 6

Explain how the enteric nervous system is linked to the CNS.

Answer 6

it’s linked by the sympathetic and parasympathetic nerve fibres :vagus nerve

Question 7

Describe the role of the following in the enteric nervous system:

a. Sensory neurons
b. Motor neurons
c. Interneurons

Answer 7

a. Sensory neurons monitor chemical changes (via chemo -receptors) in the GI tract and stretching (stretch receptors) of its walls.
b. Motor neurons govern motility and secretions of the GIT and associated glands.
c. Interneurons connect the two plexus

Question 8

1. Draw and label a neuron:
   a. Axon
   b. Dendrites
   c. Cell body
   d. Nodes of Ranvier
   e. Myelin sheath
   f. Terminal endings

Answer 8

Question 9

Define the following terms:

1. Action potential
2. Nerve stimulus
3. Nuclei
4. Ganglia
5. Tracts

Answer 9

1. Action potential: ability to create a nerve impulse
2. Nerve stimulus: anything able to generate an action potential (ext/internal)
3. Nuclei: collection of cells bodies forming structural & functional groups in CNS
4. Ganglia: same as Nuclei but in PNS
5. Tracts: axon bundles in CNS

Question 10

State which vitamin is required as a co-factor in myelin production?

Answer 10

vitamin B12

Question 11

Describe THREE key differences between ‘neurons’ and ‘neuroglial cells/ glial cells’

Answer 11

1. Glial cells are smaller
2. Glial cells 50x more prevalent
3. glial cells can multiply & divide

Question 12

Name the neuroglial cell that:

1. Contributes to the blood brain barrier
2. Is phagocytic and is mobile in the brain
3. Provides structural support in PNS ganglia

Answer 12

1. Astrocytes
2. Microglia
3. Satellite cells

Question 13

Name the neuroglial cell that:

1. Myelinates axons in the CNS
2. Produces cerebrospinal fluid
3. Produce myelin in the PNS

Answer 13

1. Oligodendrocytes
2. Ependymal cells
3. Schwann cells

Question 14

Complete the following:

Neurons at rest process an _____________ gradient across the cell membrane. This is created by the build-up of ________________ ions on the inside of the cell membrane relative to the extracellular fluid which contains more ___________ ions The separation of charges create ________________ energy. The resting potential is approximately_________ mV. Cells exhibiting a membrane potential are said to be ________________ or charged.

Answer 14

Neurons at rest possess an electrochemical gradient across the cell membrane. The resting potential is created by a build up of negative ions on the inside of the cell membrane, relative to the extracellular fluid which contains more positive ions.
The separation of charges across a cell membrane creates potential energy.
This resting potential is approximately -70mV. Cells exhibiting a membrane potential are said to be polarised or ‘charged’

Question 15

Describe in detail the resting potential (think sodium, chloride, potassium, proteins and the sodium-potassium pump).

Answer 15

Resting potential is created by the build up of negative ions inside cell membrane and positive ions outside: to ensure we have more sodium outside of the axion and potassium inside we use a sodium-potassium pump = the pump move 3 sodium molecules out for 2 potassium into. It requires energy ATP as it is an active process

Question 16

Describe in detail all steps in the following processes:

1. Depolarisation
2. Repolarisation

Answer 16

1. Depolarisation: going from -70mV to +30mV: sodium go into the axion
2. Repolarisation: +30mM to -70mV - Potassium moves out of axion

Question 17

Explain what is meant by the:

1. Refractory period
2. Absolute refractory period
3. Relative refractory period

Answer 17

1. Refractory period: period after repolarisation where sodium & potassium are on the wrong side of membrane= nerve can’t generate any action potential.
2. Absolute refractory period: even a strong impulse can’t generate any action
3. Relative refractory period: need a bigger stimulus than normal to generate action

Question 18

Describe in detail how the ‘synapse’ transmits a signal

Answer 18

synapse connects neurons: connects action potential of the axion to neurons terminal endings (synaptic end bulb) that communicate with another neuron. the neurotransmitters diffuse across the synapse and bind to receptors = open the ion channels: generating action potential

Question 19

Explain TWO differences between ‘excitatory’ and ‘inhibitory’ transmitters

Answer 19

1. Excitatory: depolarisation / inhibitory: hyperpolarisation
2. Excitatory: become more positive / inhibitory: more negative

Question 20

1. Name the amino acid precursor of glutamate
2. what are glutamate & GABA compared to glutamine

Answer 20

1. Glutamine
2. neurotransmitters

Question 21

Name ONE vitamin needed for conversion of glutamate to GABA

Answer 21

B6

Question 22

1. State the location in the brain where most dopamine is stored
2. where is most serotonin found

Answer 22

1. Substantia negra
2. gastrointestinal tract

Question 23

In a synapse, name the ion that directly causes the exocytosis of synaptic vesicles

Answer 23

calcium

Question 24

1. List TWO functions of dopamine
2. List 2 functions of serotonin

Answer 24

1. Movement, reward mechanism
2. GIT peristalsis, sleep, mood, pain regulation

Question 25

List ONE neuropeptide that enhances pain

Answer 25

Substance P

Question 26

What is the charge present in a resting membrane?

Answer 26

-70mV

Question 27

what is meant by the action potential “Threshold”?

Answer 27

it is - 55mV: it is the minimum the stimulus need to reach to generate action potential

Question 28

Explain what is meant by synapse

Answer 28

junction between 2 neurons/ neuron & muscle

Question 29

1. State TWO ways in which the following central nervous system components are protected: a. Spinal cord b. Brain

Answer 29

a. Spinal cord: vertebral column & meninges b. Brain: craniumcranial meninges, cerebrospinal fluid (CSF) and the blood brain barrier (BBB).

Question 30

1. With regards to the layers of the meninges, compare functions of the: a. Dura mater b. Arachnoid mater c. Pia mater

Answer 30

a. Dura mater: strong layer, tough. Venous sinuses= blood drain into jugular veins b. Arachnoid mater: collagen & elastic fibre c. Pia mater: delicate layer, blood vessels supply spinal cord

Question 31

Name the spaces between: a. Dura mater and arachnoid mater b. Arachnoid mater and pia mater

Answer 31

a. subdural space b. subarachnoid space

Question 32

Describe TWO key differences between ‘subdural hematoma’ and ‘subarachnoid hemorrhage’

Answer 32

1. subdural haematoma slowly develop because venous and subarachnoid is rapid as it's arterial bleed 2. subdural haematoma must like develop in elderly people with condition like Alzheimer whereas subarachnoid: aneurysm/ berry aneurysm

Question 33

List FOUR functions of CSF.

Answer 33

1. protection of brain & spinal cord , shock absorber 2. Maintain uniform pressure around the brain 3. Moist of brain & spinal cord 4. Circulation of nutrients & waste 5. Optimal chemical environment (ion) for nerve signaling

Question 34

Describe the main role of the blood brain barrier (BBB).

Answer 34

Protects the brain from toxins, bacteria's & harmful substances that enter the bloodstream

Question 35

Name the 2 arterial systems to supply blood to brain

Answer 35

Vertebral & Carotid

Question 36

Name the neuroglial cell that maintains the BBB.

Answer 36

Astrocytes

Question 37

List FOUR major parts of the brain

Answer 37

1. Brain stem 2. Diencephalon 3. Cerebrum 4. Cerebellum (little brain)

Question 38

Name the main functions of Brainstem: 1. Medulla oblongata 2. Pons 3. Midbrain

Answer 38

1. Medulla oblongata: regulate **heartbeat & breathing,** reflexes (snoozing, vomiting &hiccupping 2. Pons: help control **breathing** and relay **motor** tracts 3. Midbrain: Dopamine function : movement + eye reflex and tracking, mvt head & neck

Question 39

Name the area of the brain that contains the ‘pineal gland’ and what it secretes?

Answer 39

Epithalamus and the pineal gland secretes melatonin

Question 40

List TWO functions of the cerebellum

Answer 40

* Maintenance of **posture and balance**. * **Smoothing complex mvts/** **Coordination of movements**. * **Correction of errors** during on going movement: • E .g. learning to walk, learning an instrument. * Cognition, thought and **language processing**. * **Motor behavior** by altering circuits that influence motor pathways (corticospinal tracts).

Question 41

List THREE factors that can damage the cerebellum.

Answer 41

1. **Chronic alcohol abuse** 2. **Coeliac** disease or a **thiamine** (**vitamin B1**) 3. Cerebellar disease ‘**Ataxia**’: lack of muscle co ordination. Commonly results in **stumbling, unsteadiness, slurred speech and an intention tremor** (e.g. hand tremor when putting key in door).

Question 42

Name ONE function of the Cerebrum

Answer 42

* Sensory perception. * Motor control of skeletal muscles (movement).

Question 43

Name the area that connects the two cerebral hemispheres

Answer 43

Corpus callosum

Question 44

Name which cerebral lobe plays a role in: 1. Hearing 2. Vision 3. Motor skills 4. Sensory input

Answer 44

1. Hearing: **Temporal** lobe 2. Vision: **Occipital** lobe 3. Motor skills: **Frontal** lobe 4. Sensory input: **Parietal** lobe

Question 45

Name THREE main structures within the limbic system.

Answer 45

1. Hypothalamus 2. Hippocampus 3. Amygdala

Question 46

Name the area that plays a key role in emotions within the limbic system.

Answer 46

Amygdala

Question 47

Explain what could happen if there is damage to any of the spinal cords

Answer 47

neurological symptoms

Question 48

Name the main functions of Brainstem: 1. Thalamus 2. Hypothalamus 3. Epithalamus

Answer 48

1. Thalamus: core of the brain as 80% of diencephalon. **Major relay centre** for sensory info (receive & distribute info) 2. Hypothalamus: **regulation & homeostasis of hormones** + control **ANS /** body **temperature + appetite/satiety** 3. Epithalamus: connect limbic system to others**+ circadian** rhythm: **melatonin** production

Question 49

Name the 3 layers of Meninges

Answer 49

Dura mater/ Arachnoid mater/ Pia mater

Question 50

State what is found in the subarachnoid space

Answer 50

Cerebrospinal fluid (CSF)