Nervous System Part 1

Question 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

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

Question 2

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

Answer 2

• CNS refers to the nervous tissue in brain and spinal chord
• PNS refers to any nervous tissue not in the CNS

Question 3

Describe the role of the somatic nervous system.

Answer 3

The Somatic Nervous system is the voluntary system of the PNS.

• It transmits sensory information from the head/limbs etc to the CNS
• it transmits motor signals to skeletal muscles only

Question 4

With regards to neuron function, complete the following table:

Function&raquo_space;»> Neuron:

Processes sensory information, analyses, stores and makes decisions:

Detects internal and external environmental changes:

Produces a response to sensory information to effect change:

Answer 4

Function&raquo_space;»> Neuron:

Processes sensory information, analyses, stores and makes decisions&raquo_space;»> Integration

Detects internal and external environmental changes&raquo_space;»> Sensory

Produces a response to sensory information to effect change&raquo_space;»> Motor

Question 5

State which nervous system controls:

a. Voluntary movements
b. Involuntary movements

Answer 5

a. Voluntary movements – Somatic Nervous System

b. Involuntary movements – Autonomic Nervous system

Question 6

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

Location &raquo_space;»> Sympathetic effect &raquo_space;»> Parasympathetic effect:
Pupil:

Liver:

Heart:

Lungs:

Gastrointestinal tract:

Adrenal Glands:

Answer 6

Sympathetic effect VS Parasympathetic effect:

Pupil:
Dilation VS Contraction

Liver:
Conversion of glycogen to glucose VS Glycogen synthesis

Heart:
Heart rate and blood pressure increased VS. Heart rate and blood pressure decreased

Lungs: Bronchodilation. VS Bronchoconstriction

Gastrointestinal tract:
Reduced motility and secretions VS Increased motility and secretions

Adrenal glands:
Release adrenaline Vs No involvement

Question 7

Name the specific body location of the following:

a. Sympathetic nervous system

b. Parasympathetic nervous system

Answer 7

a. Sympathetic nervous system – Thoraco-lumbar

b. Parasympathetic nervous system – Cranio-sacral

Question 8

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

Answer 8

The enteric nervous system is the nervous system of the gut. It is linked with the CNS via the sympathetic and parasympathetic nerve fibres

Question 9

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

a. Sensory neurons
b. Motor neurons
c. Interneurons

Answer 9

a. Sensory neurons – Monitor chemical changes (via chemo receptors) in the GI tracts and stretching (via stretch receptors) of its walls.

b. Motor neurons – govern motility and secretions of the GIT and associated glands

c. Interneurons – Connect the two plexus – myenteric and submucosal

Question 10

Draw and label a neuron:

a. Axon

b. Dendrites

c. Cell body

d. Nodes of Ranvier

e. Myelin sheath

f. Terminal endings

Answer 10

Question 11

Define the following terms:

a. Action potential

b. Nerve stimulus

c. Nuclei

d. Ganglia

e. Tracts vs Nerves

Answer 11

a. Action potential – The electrical current that runs along the axon

b. Nerve stimulus – anything able to generate an action potential

c. Nuclei – cell bodies that cluster together in the CNS

d. Ganglia - cell bodies that cluster together in the PNS

e. Tracts Vs Nerves
Axon bundles are called tracts in the CNS and nerves in the PNS

Question 12

Describe the main role of dendrites.

Answer 12

Branches coming off the neuron. They are the receiving portion of the cell and they communicate with other neurons and dendrites.

Question 13

Can axons regenerate? Explain.

Answer 13

Axons can repair but only at the rate of 1-2 mm per day and it does depend on the health of the overall tissue and surrounding cells as to whether they can facilitate healing

Question 14

Describe TWO roles of the myelin sheath.

Answer 14

Electrically insulates the axon

Increases speed of signal transmission

Question 15

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

Answer 15

B12

Question 16

Describe ONE key difference between ‘grey matter’ and ‘white matter’.

Answer 16

In the CNS …

Grey:
* The appearance of tissue in certain areas of the CNS.
* It is composed of lots of cell bodies and also contains dendrites and unmyelinated axons.

White:
* It appears that way because of the myelin sheath.
* When we talk about white matter we are talking about myelinated axons.

Question 17

Fill in the diagram

Answer 17

Question 18

Describe THREE key differences between ‘neurons’ and ‘neuroglial cells’.

Answer 18

Neuron Vs Glial

Can relay an electrical signal Vs Cannot relay an electrical signal

Cannot divide. Set at birth. V Can divide and multiply

Bigger Vs Smaller

A lot less of them Vs 50 x more prevalent

Question 19

List TWO key functions of neuroglial cells.

Answer 19

• The glue that surrounds neurons and keep them in place
• Supply nutrients and oxygen to neurons
• Destroy pathogens and remove dead neurons
• Fill in the gaps left by damaged neurons

To answer this question fully, think about the functions of all 6 glial cells

Question 20

Match the nervous system CNS or PNS to the neuroglial cell:

a. Schwann cell

b. Astrocytes

c. Microglia

d. Ependymal cells

e. Satellite cells

f. Oligodendrocytes

Answer 20

a. Schwann cell - PNS

b. Astrocytes - CNS

c. Microglia - CNS

d. Ependymal cells -CNS

e. Satellite cells - PNS

f. Oligodendrocytes - CNS

Question 21

What do each of these glial cells do and where are they located?

a. Astrocytes

b. Microglia

c. Satellite Cells

d. Oligodendrocytes

e. Epindymal cells

f. Schwann Cells

Answer 21

a. Astrocytes
Contributes to the blood brain barrier and physically support neurons by wrapping around them holding them to their blood supply

b. Microglia
Is phagocytic mopping up damage in the brain and is mobile in the brain -

c. Satellite Cells
Provides structural support in PNS ganglia and exchange substances in the nervous system

d. Oligodendrocytes
Myelinates axons in the CNS

e. Epindymal cells
Produces cerebrospinal fluid

f. Schwann Cells
Myelinates axons in the PNS

Question 22

Name the neuroglial cell that:

a. Contributes to the blood brain barrier and physically support neurons by wrapping around them holding them to their blood supply -

b. Is phagocytic mopping up damage in the brain and is mobile in the brain

c. Provides structural support in PNS ganglia and exchange substances in the nervous system

d. Myelinates axons in the CNS

e. Produces cerebrospinal fluid

f. Myelinates axons in the PNS

Answer 22

a. Contributes to the blood brain barrier and physically support neurons by wrapping around them holding them to their blood supply - Astrocytes

b. Is phagocytic mopping up damage in the brain and is mobile in the brain - Microglia

c. Provides structural support in PNS ganglia and exchange substances in the nervous system – Satellite Cells

d. Myelinates axons in the CNS - Oligodendrocytes

e. Produces cerebrospinal fluid – Epindymal cells

f. Myelinates axons in the PNS – Schwann Cells

Question 23

Describe the function of these neuroglial cells in the PNS:

Satellite Cells

Schwann Cells

Answer 23

Satellite Cells
* Provides structural support in PNS ganglia
* Exchange substances in the nervous system

Schwann Cells
* Myelinates axons in the PNS

Question 24

Describe the function of these neuroglial cells in the CNS:

Astrocytes

Microglia

Oligodendrocytes

Ependymal cells

Answer 24

Astrocytes
* Contributes to the blood brain barrier
* physically support neurons by wrapping around them holding them to their blood supply -

Microglia
* Phagocytic mopping up damage in the brain
* Mobile in the brain

Oligodendrocytes
* Myelinates axons in the CNS

Ependymal cells
* Produces cerebrospinal fluid

Question 25

What is a ‘graded potential’ and ‘action potential’.

Answer 25

They are both types of electrical signal in a neuron

A graded potential is any electrical impulse that travels around the cell body and dendrites of a neuron.

An action potential is any electrical impulse that travels down the axon.

Question 26

Name TWO characteristics that facilitate graded and action potentials.

Answer 26

Specific ion channels can open and close when stimulated.

Electrical differences across the cell membrane (resting potential),

Question 27

Name TWO stimuli that trigger ion channels.

Answer 27

Ion channels are transmembrane proteins.

Na+ and K+ channels are the really important ones.

Stimuli that trigger ion channels:
- changes in voltage
- chemicals (hormones)
- mechanical pressure

Question 28

Complete the following:

Neurons at rest possess 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 -70mV. Cells exhibiting a membrane potential are said to be —– or charged.

Answer 28

Neurons at rest possess an ELECTROCHEMICAL gradient across the cell membrane. This is created by the 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 create POTENTIAL energy. The resting potential is approximately -70mV. Cells exhibiting a membrane potential are said to be POLARISED or charged.

Question 29

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

Answer 29

Inside the neuron in the intracellular fluid we will find an accumulation of
- potassium ions (K+) and also,
- large negatively charged protein molecules that cannot leave the cell.
Overall it carries a negative charge

Outside and around the neuron in the extracellular fluid we find an accumulation of sodium ions (Na +) and Chloride ions (Cl-). Overall it carries a positive charge.

Therefore we have more positivity outside than we do inside. The inside is negatively charged compared to the outside. This creates a very specific charge in our neurons. In an axon that is at rest and not carrying an electrical signal, the charge in that Neuron will be - 70mV. That is the separation of charge between the inside and the outside.

We call this disparity between the inside and the outside, this build up of negative ions on the inside of the cell membrane, relative to the extracellular fluid which contains more positive ions, the resting potential.
Why don’t things even up in the concentration gradient through passive transport? Normally it would but in this case as the NA+ as CL- try to move back to equalise the charge, the separation of charges is maintained by the sodium-potassium pump which pumps 3 Na+ out for every 2 K+ it pumps back in (using ATP).

Question 30

What are the two phases of the action potential?

Answer 30

• Depolarisation
• Repolarisation

Question 31

Describe in detail all steps in the following processes:

a. Depolarisation

b. Repolarisation

Answer 31

a. Depolarisation

Depolarisation is when a positive charge builds up inside the cell - the negative membrane potential (-70mV) becomes positive and reaches +30mV.

Step 1: Depolarisation is triggered by stimulation of a nerve ending.
Step 2: That stimulation must reach a threshold value -55mV in order to generate an action potential.
Step 3: Na+ channels open allowing Na+ to flood into the cell up to about +30mV
Step 4: A positive charge builds up inside the cell

b. Repolarisation

Repolarisation is where we get the restoration of the membrane potential to -70mV.

To do this potassium channels now open but much more slowly than Na+ channels. The result is that Na+ channels just start to close as K+ channels open.
K+ can flood out of the cell restoring the membrane potential to -70mV

Question 32

11. Explain what is meant by the:

a. Refractory period

b. Absolute refractory period

c. Relative refractory period

Answer 32

a. Refractory period
The time after depolarization and repolarization where we can’t generate another action potential.

The reason we can’t generate another action potential is because ions (Na+ and K+) are on the wrong side of the membrane and the charge is all over the place.

b. Absolute refractory period
Even a really strong stimulus would not be able to generate an action potential because the ions are in the wrong place.

c. Relative refractory period
The time when you could generate another action potential but the stimulus would have to be bigger than the original stimulus.

Question 33

Describe the difference between continuous conduction and saltatory conduction under the following headings:

Myelination
Depolarisation
Speed
Energy efficiency

Answer 33

ContinuousVS Saltatory

Myelination: Unmyelinated VS myelinated

Depolarisation: Step-by-step VS Leaps

Speed: Slower VS Faster

Energy efficiency: Less VS more

Question 34

Describe the role of the Nodes of Ranvier.

Answer 34

At the nodes of Ranvier, there are high concentrations of Na+ gates. This causes the current to appear to jump from node to node (saltatory conduction).

Question 35

Explain why ‘ice’ is applied to an injury.

Answer 35

Cold slows down action potentials. Ice pain signal’s are relayed more slowly.

Question 36

Describe in detail how the ‘synapse’ transmits a signal.

Answer 36

Synapse receives the depolarising wave and we get sodium channels opening and sodium entering the axon again and again.

This causes calcium channels to open and we get the influx of calcium into the synaptic bulb.

Sodium in in droves…then calcium …

When calcium ions are in large quantities in that synaptic end bulb, they cause the synaptic vessels which store the neurotransmitter to break down and that process of break down is known as exocytosis.

Neurotransmitters are released into the synaptic cleft.

The released neurotransmitters diffuse across this gap (the synaptic cleft) and bind to receptors on the post synaptic neuron.

This causes something to happen in the next neuron depending on whether it is excitatory (continues) or inhibitory (stops) .

Question 37

Which category do the following neurotransmitters belong to?

a. GABA

b. Dopamine

c. Acetylcholine

d. Serotonin

Answer 37

a. GABA – Amino Acid

b. Dopamine - Monoamine

c. Acetylcholine – Unique molecule

d. Serotonin - Monoamine

Question 38

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

Answer 38

Question 39

Name TWO ways in which neurotransmitters are inactivated following a nerve impulse.

Answer 39

Between impulses the transmitter molecules are rapidly removed from the synaptic cleft to prevent continuous stimulation of postsynaptic neurons.

There are two types of removal:

Re-uptake – the neurotransmitter is reabsorbed back into the presynaptic neuron and restored inside a vesicle ready to be used again.

Enzyme degradation – neurotransmitter is broken down by an enzyme (such as MAO) into smaller inactive product which are then reabsorbed by the presynaptic neuron and resynthesised into active neurotransmitter.

Question 40

Name the amino acid precursor of glutamate.

Answer 40

Glutamine

Question 41

Indicate if GABA is a major inhibitory or excitatory neurotransmitter.

Answer 41

Inhibitory

GABA is an inhibitory neurotransmitter. It lessens a nerve cell’s ability to receive, create or send chemical messages to other nerve cells.

GABA is known for producing a calming effect.

Question 42

Name ONE vitamin needed for conversion of glutamate to GABA.

Answer 42

B6

Question 43

Name the amino acid precursor of:

a. Serotonin

b. Dopamine

Answer 43

a. Serotonin - Tryptophan

b. Dopamine - Tyrosine

Question 44

Describe serotonin’s role in the gastrointestinal tract.

Answer 44

It is needed to encourage intestinal motility (peristalsis) and epithelial cell secretion.

Question 45

Name TWO functions (not GI tract) of serotonin.

Answer 45

Sleep regulation

Pain

Attention

Learning and memory

Thermoregulation

GIT intestinal motility

Question 46

State the location in the brain where most dopamine is stored.

Answer 46

It is particularly abundant in the substantia nigra.

Question 47

List TWO functions of dopamine.

Answer 47

Movement - Patients with Parkinson have a lack of dopamine in the substantia nigra

Reward mechanisms – Dopamine released with sugar, alcohol, cocaine

Regulating muscle tone

Cognition and emotion

Question 48

List ONE function of acetylcholine.

Answer 48

Muscle contractions

Cognition – Embedding and recalling memory. 90% of Alzheimer’s patients are deficient in ACH

Question 49

Name TWO natural body analgesics

Answer 49

Endorphins are hormones that are released when your body feels pain or stress.

They are produced in your brain and act as messengers in your body.

Help to
* improve mood.
* relieve pain
* reduce stress

Endorphins can be boosted by exercising, eating, having sex, getting a massage and many other ways.

Endorphins

Dynorphins

Enkephalins

Question 50

List ONE neuropeptide that enhances pain.

Answer 50

Substance P

Question 51

List TWO neurotransmitters broken down by MAO.

Answer 51

Serotonin.
Adrenaline.
Noradrenaline.
Dopamine.

Question 52

List TWO neurotransmitters broken down by COMT.

Answer 52

Adrenaline.
Noradrenaline.
Dopamine.

Question 54

Explain what is meant by a synapse

Answer 54

A junction between two neurons or a neuron and a muscle

Question 55

Where is most serotonin found

Answer 55

In the GIT - 95% of it

Question 56

Describe TWO signs / symptoms of an injured spinal nerve.

Answer 56

Tingling; Numbness; pain&raquo_space;> in the associated distribution

Question 57

Describe the main role of spinal nerves.

Answer 57

They carry impulses to and from the spinal cord

Question 58

Why is the power of a neuron to regenerate based on its location

Answer 58

PNS fibres can regenerate but only if
1. the cell body is intact because that is where the nucleus would be. The nucleus is needed to code for the newly produced axon.
2. Schwann Cells are present

CNS nerve fibres do not retain the capacity to undergo division/regenerate

However….If a patient was to damage an area of tissue within the CNS we can sometimes get neuroplasticity. We adapt and create new pathways

Question 59

Describe how the signs / symptoms develop in carpal tunnel syndrome (CTS).

Answer 59

The carpal tunnel is a narrow passageway in the anterior wrist that contains tendons and the median nerve.

This median nerve provides sensory information to the hand and controls movements in the hand and fingers

The median nerve becomes compressed in the wrist and hand carpal tunnel syndrome.

Question 60

List TWO pathologies that can cause Carpal tunnel syndrome (CTS)

Answer 60

Pathologies - RA, Hypothyroidism, acromegaly

Also – fluid retention due to pregnancy, overuse, posture, using vibrating tools

Question 61

State TWO signs / symptoms of carpal Tunnel Syndtome - CTS.

Answer 61

• Tingling, numbness or pain in the median nerve distribution.
• Symptoms are often worse at night
• Weakness of grip and weak thumb opposition

Question 62

List ONE test used to diagnose CTS.

Answer 62

Two tests that will reproduce carpal tunnel syndromes if the median nerve is at play:

Tinel’s test (tapping on the median nerve) depolarises the median nerve. If there is damage, by tapping this it will create symptoms very quickly

Phalen’s test - also reproduces symptoms

Question 63

Define Bell’s palsy.

Answer 63

The nerve that controls the facial muscles (facial nerve) becomes inflamed or compressed.

Question 64

List ONE viral cause of Bell’s palsy.

Answer 64

Herpes simplex

Question 65

Name TWO characteristic signs / symptoms of Bell’s palsy.

Answer 65

• Sudden unilateral weakness or paralysis of the facial muscles.
• Sometimes cannot close eye on affected side
• Loss of taste and intolerance to loud noise if severe

Question 66

Name the pathological feature common to Guillain Barre Syndrome (GBS) and multiple sclerosis.

Answer 66

Both autoimmune and both interfere with laying down of myelin on axons

Question 66

Using definitions compare Guillain barre syndrome and multiple sclerosis.

Answer 66

Guillain-Barre is a form of post-infectious de- myelinating disease with neuritis. It is associated with acute, ascending, progressive inflammation and demyelination of peripheral nerves.

MS is autoimmune inflammatory disease causing demyelination of axons in CNS neurons with damage. T-Lymphocytes attack myelin antigens. Multiple areas of sclerosis (scar tissue) along axons disrupt conduction.

MS and GBS are both auto immune and both inflammatory and both demyelinating. MS is in the CNS and GBS in the PNS.

Question 67

List ONE viral cause of Guillain barre syndrome (GBS)

Answer 67

Epstein-Barr
in 75% of cases it is autoimmune after an infection like Epstein-Barr

Question 68

Describe what is meant by ‘molecular mimicry’ in GBS.

Answer 68

In 75% of cases GBS is triggered by a recent infection (one–three weeks after respiratory / GIT infection or post-vaccination e.g., flu / EBV).

Molecular Mimicry is where antibodies formed against virus cross react with lipids in myelin.

Question 69

Name TWO signs / symptoms of GBS.

Answer 69

Guillain–Barré syndrome ( GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system.

• Sudden, progressive, bilateral ascending paralysis.
• Paraesthesia (pins and needles)and sensory changes.
• Neuropathic pain into legs.

Question 70

Describe the pathophysiology of multiple sclerosis.

Answer 70

It is an autoimmune, inflammatory and demyelinating disease in the CNS

T lymphocytes attack myelin antigens on the CNS,
* leading to multiple areas of sclerosis (hardening/scar tissue) along axons,
* leading to disruptions in conduction
* leading to multiple systems including vision issues, deafness and loss of balance, burning and pulling sensations, tingling and loss of sensation, cognitive changes and depression, weakness, bladder urgency and incontinence

Question 71

Describe the main pattern of multiple sclerosis.

Answer 71

Relapsing – Remitting: Most MS follows a relapsing-remitting pattern (85%) where the disease goes from relapse to remission to relapse etc

Primary – Progressive: Serious from the start and progress from the start. Poor prognosis

Secondary – Progressive: When it starts as relapsing-remitting and as the disease progresses it becomes progressive

Question 72

Explain how the following vitamins can contribute to multiple sclerosis

Vitamin D
Vitamin B12

Answer 72

Vitamin D
Low Vit D is one of the biggest risk factors for MS. Oligodendrocytes need it to produce myelin.
* Correlation between Vit D deficiency/proximity to the equator and MS
* Correlation with other countries that also are known to have Vit D deficiency, for example because they apply a lot of sunscreen or cover skin for religious reasons Eg: Australia and Saudi Arabia

Vitamin B12
B12 normally acts as a co-factor in myelin formation and also has immunomodulatory effects.

Question 73

List ONE viral trigger of multiple sclerosis.

Answer 73

Epstein-Barr

Question 74

Name the diagnostic tool which can be used to view optic nerve demyelination in multiple sclerosis.

Answer 74

MRI Opthalmoscopy

Question 75

List FOUR signs / symptoms of multiple sclerosis.

Answer 75

Working down the body …

1. Cognitive changes and depression.
2. Visual symptoms are common: Blindness, loss of vision of one eye and occasional pain (neuritis). Double vision and nystagmus (jerking of eyeball).
3. Deafness and loss of balance.
4. Bladder urgency and incontinence.

More general symptoms
1. Paraesthesia
- Burning, pulling sensations.
- Tingling and loss of sensation.

2. Weakness

Question 76

Define motor neurone disease (MND).

Answer 76

The progressive degeneration of motor neurons in the spinal cord, motor cortex and brain stem.

MOTOR not sensory therefore no sensory symptoms like tingling/numbness but motor symptoms like paralysis and weakness.

Question 77

Discuss ONE suggested pathophysiology for MND.

Answer 77

The current hypotheses focus on abnormal mitochondrial function causing oxidative stress in motor neurons.

Genetics is also implicated

Question 78

List TWO characteristic signs / symptoms of MND.

Answer 78

1. Typically presents as weakness in upper limbs - dropping objects or difficulty manipulating objects.
2. Wasting of hand muscles and tremor of limbs at rest.
3. Later stages can affect the legs (tripping), cause slurred speech, dyspnoea and dysphagia.
4. Death by respiratory failure — typically within 3–5 yrs

Question 79

Describe the difference between dementia due to:

a. Alzheimer’s disease (AZ)

b. Vascular dementia

Answer 79

a. Alzheimer’s disease (AZ)
50% of dementia diagnosis. Associated with
* Degeneration of the cerebral cortex
* Reduced acetylcholine production
* Deposition of Protein Plaques called beta amyloid plaques

b. Vascular dementia
25% of dementia diagnosis
* Associated with cardio vascular disease and poor oxygen delivery
* Often associated with stroke or multiple strokes cutting off circulation in aregion of the brain
* Parkinson’s disease.

Question 80

Describe in detail the pathophysiology of Alzheimers

Answer 80

Alzheimer’s is a neurodegenerative disease of the cerebral cortex.

The hippocampus is among the areas first affected. It is where we store memories. As the hippocampus degenerates we lose the ability to recall these memories. Typically, more short term memories.

Later as the disease progresses it spreads to the amygdala which is the area of the brain that is active when we are dealing with emotions and longer term memories.

Whilst progressing, additional regions of brain become affected.

Associated with Beta Amyloid plaques, atrophy of neurons and less acetycholine.

Beta amyloid plaques are the key diagnostic feature of alzheimers.

Question 81

Name the areas of the brain affected by:

a. Earlier stages of AZ

b. Later stages of AZ

Answer 81

a. Earlier stages of AZ
Hippocampus

b. Later stages of AZ
Amygdala

Question 82

Explain how the following factors could contribute to AZ:

a. Homocysteine

b. Stress

c. Hormones defieicieny

d. Heavy metals

e. Chronic inflammation

Answer 82

a. Homocysteine
* The Amino acid homocysteine needs to be converted to methionine. This conversion needs B6/9/12 vitamins and thus we accumulate more homocysteine because it isn’t converted
* High increases risk.
* Facilitate a build-up of toxic β-amyloid and tau in the brain

b. Stress
* Higher cortisol levels linked to memory issues

c. Hormones defiicieny increases risk of cognitive impairment

• Oestrogen deficiency can make post menopausal women more prone to learning and memory problems.
• Testosterone deficiency in men as it has a neuroprotective effect.
• Thyroid hormone deficiency linked to an increased risk of cognitive impairment.

d. Heavy metals

Thought to degenerate the blood brain barrier and allow some of the other substances to enter through.
* Excessive levels of copper (sml qty is beneficial)
* Mercury.
* Aluminium toxicity (e.g. from vaccines, cans, foil, antiperspirants etc.).

e. Chronic inflammation

• Such as sugar (and insulin resistance), dairy, gluten.
• Leaky gut (promoting inflammation).Gluten is implicated here.

Question 83

Identify which gene is associated with AZ.

Answer 83

ApoE4 gene

Question 84

Name TWO nutritional deficiencies associated with AZ.

Answer 84

B1, B3, B6, B12, folate, omega-3 fatty acids.

Question 85

Name ONE micro-organism that may contribute to AZ.

Answer 85

a. Oral bacteria such as P. gingivalis have been identified in tissue biopsies.
b. Herpes simplex virus.

Question 86

List TWO signs / symptoms associated with:

a. Early stages of AZ

b. Later stages of AZ

Answer 86

a. Early stages of AZ
Hippocamous Stage
* Slight memory loss (especially short-term) i.e., forgetting recent conversations.
* Repeated questions and confusion.
* Decreased initiative (↓hobbies, ↓hygiene)

b. Later stages of AZ
Amygdala Stage
* Significant memory loss (incl. long-term memory).
* Subtle changes in higher order functions i.e. understand jokes.
* Mood disturbances: agitation and aggression.
* ‘Loss of sense of self’ — autobiography (left hippocampus).
* Difficulty with language, unsteady, depression.

Question 87

Using pathophysiology, compare Parkinson’s disease with Alzheimer’s disease.

Answer 87

Parkinsons is a progressive neurological movement disorder affecting movement caused by degeneration of dopamine producing neurons in the area of the brain called the substantia nigra located in the mid brain. It leads to an accumulation of abnormal protein plaques (Lewy bodies) within neurons.

Alzheimers is also a neurodegenerative disease but it is of the cerebral cortex staring at the hippocampus and moving to the amygdla. It affects memory and emotion. It only affects movement in later stages but this is due to loss of memory. It leads to a build of beta amylin plaque.

Question 88

List TWO causes of Parkinson’s disease.

Answer 88

• Mitochondrial dysfunction (oxidative stress).
  *Genetics.
• Constipation and diet low in polyunsaturated fats.
• Toxic environmental factors:
  i.e.carbon monoxide, manganese poisoning, exposure to pesticides and herbicides.

Question 89

List THREE characteristic signs / symptoms of Parkinson’s disease.

Answer 89

• Bradykinesia: Short, shuffling steps (difficulty stopping / starting)
• Resting tremor (‘pill rolling’).
• Stooped / flexed posture/ arms at side
• Lack of normal subconscious movements (swinging arms).
• Muscle rigidity, mask-like face
• Low/deep voice.

Question 90

What is Huntington’s Disease?

Answer 90

• Genetic disease with a defect on chromosome 4
• An inherited neurodegenerative disorder affecting the basal ganglia
• Results in loss of muscle coordination (chorea), cognitive impairment and poor regulation of mood and emotions.

Note: The basal ganglia are located in the brain stem, thalamus, and cerebral cortex areas of the brain. This group of structures is important in regulating voluntary movements.

Question 91

What is the nerve involved in carpal tunnel syndrome

Answer 91

Median Nerve

Question 92

What is the nerve implicated in Bell’s palsy

Answer 92

Facial nerve

Question 93

At what age are individuals typically affected by
A. Multiple Sclerosis
B. Motor neuron disease

Answer 93

A. Multiple sclerosis – 20 to 50

B. Motor neuron disease – 50 - 70

Question 94

State three suspected causes/risk factors of Alzheimer’s

Answer 94

Heavy metals

Chronic inflammation – gluten, dairy, sugar

Bacteria like gingivitis

High homocysteine levels

High cortisol levels

lots of free radicals

lots of atherosclerosis/cardiovascular disease

Genetics

Question 95

Name the part of the brain affected by Parkinson’s disease

Answer 95

Substantia Nigra

Question 96

Name 8 neurotransmitters of the nervous system

Answer 96

Glutamate

GABA

Seratonin

Dopamine

Adrenaline and noradrenaline

Acetylcholine

Nitric Oxide

Question 97

For the neurotransmitter glutamate… answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 97

Glutamate is the most abundant excitatory neurotransmitter released by nerve cells in your brain. It plays a major role in learning and memory. For your brain to function properly, glutamate needs to be present in the right concentration in the right places at the right time. Too much glutamate is associated with such diseases as Parkinson’s disease, Alzheimer’s disease and Huntington’s disease.

Primary mode of action: Excitatory
Location it works in - CNS
Derived from what amino acid - Glutamine
Role - Memory, learning

Question 98

For the neurotransmitter GABA… answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 98

Primary mode of action - Inhibitory
Location it works in - Brain
Derived from what amino acid - Glutamate together is vitamin B6 dependent
Role - Prevents neural overactivity

Question 99

For the neurotransmitter serotonin… answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 99

Primary mode of action - Inhibitory
Location it works in - 95% enteric nervous system and 5% CNS
Derived from what amino acid - Tryptophan
Role -
Sleep
Attention
Intestinal mobility and secretions
Pain regulation

Question 100

For the neurotransmitter dopamine … answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 100

Primary mode of action: inhibitory

Location it works in: Brain - Substantia Nigra

Derived from what amino acid: Tyrosine

Role:
Reward
Cognition
Movement
Muscle tone

Question 101

For the neurotransmitters Adrenaline and Noradrenaline… answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 101

Primary mode of action: Excitatory

Location it works in:
Sympathetic nervous system; Brain - motor Neurons

Derived from what amino acid: Tyrosine

Role: mobilise body and brain to take action when danger

Question 102

For the neurotransmitter acetylcholine… answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 102

Primary mode of action: Excitatory

Location it works in:
Parasympathetic nervous system
CNS
motor neuron junction

Derived from what amino acid - N/A

Role:
Muscle contraction
cognition

Question 103

For the neurotransmitter Nitric Oxide… answer the following:

Primary mode of action
Location it works in
Derived from what amino acid
Role

Answer 103

Primary mode of action:
Excitatory

Location it works in:
Smooth muscle

Derived from what amino acid:
Arginine

Role: vasodilation

Question 104

What are the causes of Multiple Sclerosis

Answer 104

Autoimmune

Genetics

Vitamin D and vitamin B 12 deficiency

Question 105

Name the key differences between a graded potential and an action potential

Answer 105

Graded potentials are changes in membrane potential that vary according to the size of the stimulus, as opposed to being all-or-none

Graded Potential:
* for short distance, communication
* occurs in dendrites and cell body
* No threshold
* Longer duration

Action potential:
* for long-distance communication
* Occurs along the axon
* All or nothing – has a threshold
* Shorter duration