Test 3 Flashcards by Sophie Wilson

Name the four parts of the neurone and their function?

Dendrites – processes on the cell that receive connections from other neurons.
Cell body (soma) – where the nucleus and most organelles of the cell are located
Axon – a specialised structure to conduct the nerve signal to its target
Synapse – the end of the axon that passes the signal to another cell

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Describe the phases of the action potential and what occurs in each phase?

Membrane potential hits -55 mv
Voltage gated Na+ channels open
o Na+ rushes into the cell
o Membrane is depolarised
o Membrane potential reaches +40mV
o Voltage gated Na+ channels close
At +30mV voltage gated K+ channels open,
o K+ rush in to restore the membrane charge
o Repolarisation
Pushes into hyperpolarisation
o K+ equilibrium is closer to -90mV
Neurone can’t be fired during this “refractory period”

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How long does the process of the action potential take

Whole process takes about 2 milliseconds

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What are channels in the cell membranes?

Neurons have cell membranes which contain ion channels. Ions can pass through these channels if they are open to change the charge on the membrane and help create electrical signals such as action potentials.

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What are energy dependent channels

Energy dependent channels:
* Require energy (usually from ATP) to move ions, often against their concentration gradient.
* Sodium/potassium pumps moves 3 Na+ ions out of the cell and 2 K+ ions in.
* Results in higher Na+ outside the cell and higher K+ inside.

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what are charge dependent channels

Charge dependent channels:
* Allow ions to pass based on charge.
* The sides of the channel may have a positive charge
* This will repel positive ions but attract negative ions and vice versa.
* This is called electrochemical exclusion and isn’t dependent on ion size.

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what are size dependent channels

Size dependent channels:
* Only allow ions of a certain size to pass.
* The channel’s diameter may match the ion’s diameter.

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what are ligand gated channels

Ligand gated channels:
* Open when a specific molecule (ligand) binds to a part of the channel.
* These are known as ionotropic receptors.

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what are mechanically gated channels

Mechanically gated channels:
* Open due to physical changes like membrane distortion, common in touch receptors.
* Temperature changes may also affect these channels.

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what are voltage gated channels

Voltage gated channels:
* Open in response to changes in membrane electrical charge.
* Example: Na+ channels may open at -55mV and close at +40mV.

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what are leakage channels

Leakage channels:
* Randomly open and close due to intrinsic switching, allowing ions to “leak” through.

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name the amino acid neurotransmitters and their roles

Glutamate – most common excitatory neurotransmitter in the body
GABA - most common inhibitory neurotransmitter in the brain
Glycine – most common inhibitory neurotransmitter in the spinal cord

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name the peptide neurotransmitters and their roles

Endorphins - pain modulation

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name the monoamine neurotransmitters

Serotonin
Histamine
The catecholamines
Dopamine
Adrenaline
Nor adrenaline

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name the “others” neurotransmitters and their roles

Acetylcholine – memory and brain activation

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Can I describe the basic roles of the neurotransmitter groups?

Amino Acids: Key for fast synaptic transmission; glutamate is excitatory, while GABA is inhibitory.
Peptides: Chemical chains or polymers of amino acids. Modulate pain
Monoamines: Organic molecules with an amino group bound to an organic acid. Involved with things like activation of the brain, emotion, consciousness and attention
Others: Memory and brain activation

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describe the function of the frontal lobe and its borders

Motor – movements, thoughts, speech
Decision making, planning
Motivation
Social decisions
Border
Divided from the temporal lobe by the large sylvian fissure
divided from parietal lobe by centrsl sulcus

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describe the function of the occipital lobe and its borders

Vision
Border
Divided from the temporal & parietal lobes by arbitrary boundaries

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describe the function of the temporal lobe and its borders

Hearing
Speech comprehension
Emotion
Memory
Border
Divided from the frontal lobe by central sulcus.
parietal & occipital lobes by the large Sylvian Fissure and arbitrary boundaries

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describe the function of the parietal lobe and its borders

Somatosensory (body sensation)
Integration of sensation
Spatial awareness
Reading, speech comprehension
Borders
Divided from the frontal lobe by the central sulcus.
Divided from the temporal & occipital lobes by the large Sylvian Fissure and arbitrary boundaries

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what are the 4 lobes of the brain

FOPT

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Can I describe the differences between Grey and White matter?

Grey matter
* Grey matter contains more neuronal cell bodies
* Cell bodies are grey in colour

White matter
* White matter contains more axons
* Fibres (axons) connecting areas of the nervous system
* White colour comes from the myelin surrounding the axons

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How many spinal nerves are where do they emerge from?

There are 31 spinal nerves emerging from:
* Cervical: 8 (C1-C8)
* Thoracic: 12 (T1-T12)
* Lumbar: 5 (L1-L5)
* Sacral: 5 (S1-S5)
* Coccygeal: 1

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What are the 2 roots that connect the spinal nerve to the spinal cord and their function?

Ventral root (front): Carries motor fibres (axons) from the spinal cord to the muscles, allowing movement.

Dorsal root (back): Carries sensory fibres from the body to the spinal cord (touch, pain, temperature, etc.).

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what are the contents of the dorsal root ganglion

The dorsal root ganglion contains mostly neuron cell bodies of sensory nerve fibres.

what are the levels that the spinal nerves exit from

* The C1-7 cervical nerves exit above their respective vertebrae * C8 nerve exits below C7 vertebrae * T1 and below exit below their respective vertebrae * The lower the nerve root, the more it descends before exiting

what are long tracts

Long tracts are the axons passing from the brain to the spinal cord, and vice versa

what are the long tracts

Corticobulbar Corticospinal Medial Lemniscus Anterolateral System

what is the function of the Corticobulbar long tract

Motor innervation to cranial nerves in brainstem

what is the function of the corticospinal long tract

Voluntary motor function

what is the function of the medial lemniscus long tract

transports messages for light touch and vibration from body

what is the function of the anterolateral system long tract

carries messages of pain and temperature from body

Can I name and locate the position of the sections of the brainstem?

Medulla oblongata – most caudal (bottom) * Contains cranial nerves parts of 8, 9-12 Pons – middle section * Contains cranial nerves 5-8 Mesencephalon/Midbrain – most rostral (top) * Contains cranial nerves 3 & 4

Can I name the two structures making up the Diencephalon and its location?

Located at the top of the brainstem Thalamus Hypothalamus and pituitary

function of the brainstem

* Controls vital functions (breathing, HR) * Origin of most cranial nerves * Eye movements * Passage for long tracts

function of the thalamus

Relay centre of the brain

function of the hypothalamus

Contains the anterior hypothalamus (parasympathetic) and the posterior hypothalamus (sympathetic). Anterior hypothalamus: * Rest and digest (relax) (parachute down) * Slowing of heart * Constriction of pupil Posterior hypothalamus: * Fight or flight response * Increased heart rate and bp * Pupillary dilation

function of the cerebellum

Attaches to the back of the brainstem * Motor functions * Coordination of movements * Rhythm * Timing * Error correction

function of the basal ganglia

Inhibit and coordinates motor movement Modulates activity of the cerebral cortex by regulating the thalamus * Allows excitation, and/or * Inhibits Has involvement in: * Motor function * Learning * Emotional processing

Can I briefly describe the arterial supply of the brain?

Supplied by the internal carotid and vertebral arteries Vertebral arteries supply the brainstem, underside of the cerebrum, occipital cortex Internal carotid supplies the remainder of the cerebrum and retinas

What is the circle of Willis

Formed by the joining of the anterior and posterior cerebral arteries Arteries arising from here supply most of the brain

what are the 3 plexuses

cervical plexus brachial plexus lumbosacral plexus

what spinal levels does the cervical plexus originate from

Forms from the nerve roots of C1 to C5

function of cervical plexus

Function: Supplies many of the neck muscles, giving sensation over the back of the head, neck and supraclavicular. Gives rise to the phrenic nerve innervating the diaphragm.

what spinal levels does the brachial plexus originate from

Arises from C5 to T1

function of the brachial plexus

Function: Gives rise to the nerves (median, ulnar, radial) supplying the upper limb. Often involved in thoracic outlet syndromes and injury/trauma

what spinal levels does the lumbosacral plexus originate from

Arises from L1 to S5

function of the lumbosacral plexus

Function: Gives rise to the nerves supplying the lower limb. Often involved in clinical presentations in chiropractic practice

Describe the CNS

* The brain and the spinal cord

Describe the PNS

* Those parts of the nervous system outside of the brain and the spinal cord

Where does the spinal cord begin?

foramen magnum

What are the meninges function?

Their function is to: * Protects the brain * Structural support * Helps with circulation of ventricle and cerebrospinal fluid (CSF)

Describe the layers of the meninges surrounding the spinal cord and brain

Dura mater - outer Arachnoid mater - middle Pia mater – inner The dura mater continues as the Epineurium

Regarding the anterior and posterior hypothalamus, what would occur in healthy function?

In healthy function the anterior should regulate/inhibit the posterior

What are the components of the axon?

* Axon hillock (beginning) * Axon proper (middle) * Axon terminal (end)

Describe the inside of the cell and outside of the cell contents

* The inside of the cell contains more potassium (K+) * The outside fluid contains more sodium (Na+) and chloride (Cl-) * More Na+ is pumped out than K+ pumped in * Results in a negative charge inside the cell

What is an action potential and how is it produced

* The action potential is the signal that travels down the axon causing the release of the neurotransmitters * Produced by allowing Na+ ions to rush into the neuron, and K+ ions to rush out

What mV is an action potential triggered

-55mV

Describe the myelin sheath

* “Insulating layer” around an axon * Increases speed of the wave of depolarisation down the axon membrane towards the axon terminal

Describe the nodes of Ranvier

* Gaps between myelin wrapped around the axon * Allows an electrical impulse to “skip” from node to node down the full length of an axon. Thus, speeds the arrival of the impulse at the nerve terminal

What part of a neuron receives signals

Dendrites

Where are neurotransmitters released

Synaptic cleft

Myelin increases conduction speed (T or F)

True

What is the resting membrane potential

-70mV

What is the role of the anterolateral system

Carries messages of pain and temperature

Which ion is more concentrated outside the cell

Sodium na+

What happens at +30mv in an action potential

K+ channels open

Which is the most common excitatory neurotransmitter

Glutamate

Which neurotransmitter is important for memory

Acetylcholine

Which neurotransmitter is a peptide

Endorphins

Which ion is more concentrated inside the cell

Potassium

Which neurotransmitter is inhibitory in the brain

GABA

Ligand gated channels open with binding molecules (T or F)

True

What happens to the cell during depolarisation

Na+ rushes in

Which neurotransmitter is used by 75% of autonomic neurones

Acetylcholine

Which lobe of the brain is involved in decision making

Frontal

The spinal cord ends where

L1/2

What does the internal capsule contain

Axons

Which plexus supplies the upper limb

Brachial plexus

What does the dorsal root contain

Sensory fibres

The anterior hypothalamus is associated with....

Parasympathetics

Test 3 Flashcards

(81 cards)