WEEK 2 LECTURE + TUTORIAL Flashcards

MECHANICS OF THE NS (43 cards)

1
Q

Lobes of the Brain

A

*Divided into four main lobes, which are apart of the cerebral cortex

  1. Frontal Lobe
    2.Parietal Lobe
    3.Temporal Lobe
    4.Occipital Lobe
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2
Q

Frontal Lobe
Location, functions, damage

A

Location: Front of the brain, behind the forehead
Functions: Higher cognitive functions (problem-solving), motor control (voluntary movement), speech production (Broca’s area) , personality and emotions (regulates behaviour and impulses)
Damage: can lead to personality changes, poor judgement and motor deficits

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3
Q

Parietal Lobe
Location, Functions, Damage

A

Location: Behind the frontal lobe, at the top- middle of the brain
Functions: Sensory processing (contains the somatosensory cortex which interprets pain), spatial awareness (depth perception), mathematical reasoning (problem-solving skills)
Damage: problems with reading and writing, agnosia issue recognising objects by touch

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4
Q

Temporal Lobe
Location, function, damage

A

Location: Both sides of the brain, near the ears
Functions: Hearing and language comprehension (contains hippocampus and Wernicke’s area), emotional regulation (processing emotions and social interactions)
Damage: memory loss, difficulty understanding speech (Wernicke’s aphasia) and emotional instability

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5
Q

Occipital Lobe
Location, Function, Damage

A

Location: At the back of the brain, behind the eyes
Functions: Visual processing (contains the primary visual cortex), object and facial recognition (helps in identifying people and objects
Damage: Vision problems, hallucinations or difficulty recognising faces (prosopagnosia)

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6
Q

Summary

A

Frontal: Forehead, Thinking
Parietal: Top, Perception
Temporal: Ears, hearing, comprehension
Occipital: Eyes, visual interpretations

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7
Q

CNS: Spinal Cord

A
  • Continuous with brainstem
    -Long, conical structure
    -Thickness of adults middle finger
    -Mediates transmission of info from the brain and the body
    -Protected by vertebrae
    -Core of grey matter
    -Grey Matter: Processing and Cognition
    -White Matter: Communication between brain regions
    -Discs between vertebra to buffer them from shock
    -Dorsal: Towards the back
    -Ventral: Towards the front
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8
Q

Main Functions

A
  • Coordinating certain reflexes
    -Conduit ( a channel for something to flow) for sensory and motor information
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9
Q

Afferent VS Efferent Neurons

A
  • Afferent Neurons (Sensory): These carry signals from the body to the spinal cord (like touch, pain, or temperature). Their axons enter through the dorsal root and connect to the dorsal horn of the spinal cord. Think of “afferent” as “arriving” at the spinal cord.
  • Efferent Neurons (Motor): These send signals from the spinal cord to muscles and organs to produce movement or responses. Their cell bodies are located in the ventral horn, and their axons exit through the ventral root. Think of “efferent” as “exiting” the spinal cord to cause an effect.
  • Afferent = sensory, arrives at the spinal cord through the back (dorsal)
  • Efferent = motor, exits from the front (ventral) to control movement
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10
Q

PNS: Main Functions

A
  • Connects the CNS to limbs and organs via cranial and spinal nerves
    -Carries info from the environment to CNS
    -Carries messages from the CNS to muscles and glands (efferent neurons)
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11
Q

Cranial Nerves Facts

A

-12 pairs
-10 Brainstem, 1/11 in Forebrain
-Exception: Vagus Nerve

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12
Q

Vagus Nerve / Wandering Nerve

A
  • Transmits information to your gut and enteric system
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13
Q

12 Cranial Nerves

A
  • Olfactory (smell)
    -Optic (vision)
    -Oculomotor (eye movement)
    -Trochlear (eye movement)
    -Trigeminal (face sensation)
    -Abducens (eye movement)
    -Facial (facial movement)
    -Vestibulocochlear (hearing)
    -Glossopharyngeal (taste)
    -Vagus (movement)
    -Accessory (neck movement)
    -Hypoglossal (tongue movement)
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14
Q

Spinal Nerves PNS

A
  • 31 Pairs
    -Each pair associated with a particular segment of the spinal cord
    -Named dependent on vertebral level they attach
    -Spinal nerves can contain sensory and motor fibres
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15
Q

Somatic NS

A

-Voluntary control of body movement
-Recieves sensory info and controls spinal nerves that innervate skin, joints and muscles
- Afferent neurons carry sensory info from the skin (sensory neuron)
-Efferent neurons control skeletal muscles (motor neuron)
-Neurons are excitatory

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16
Q

Autonomic NS

A

-Controls involuntary functions and internal environment
-Afferent neurons carry sensory info from internal organs to CNS
Has three further subdivisions
1. Sympathetic Nervous system
2. Parasympathetic Nervous System
3. Enteric Nervous System

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17
Q

ANS Functions

A

-Any response for activities which expend energy
-Coordinates fight or flight
- Activities involves with the increase in the body’s supply of stored energy
-Rest and relax response

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18
Q

ENS Functions

A

-The ‘second brain’
-Lines your gastrointestinal tract from oesophagus to rectum
-Main role in controlling digestion
-Activity dependent on local factors

19
Q

Gut-Brain Axis:

A

-Complex interplay between gut microbiota, the immune system and the CNS
-Gut microbiota regulates brain function by preserving the CNS immune homeostasis
-Direct action Vagus Nerve
-Indirect immune

20
Q

Sensory Neurons

A

-Part of the PNS
-Contain sensory receptors for detecting sensory changes
-Sends info about these changes to the CNS
-Cell body in PNS, axons enter CNS
-Axon terminals located in CNS

21
Q

Motor Neurons

A

-Part of the PNS
-Synapses to skeletal muscle to command movement or onto glands to release hormones
-Relays signal from CNS to PNS
-Dendrites and cell body in CNS, axon enters PNS

22
Q

Relay Neurons

A

-Part of the PNS
-Synapses to skeletal muscle to command movement or onto glands to release hormones
-Relays signal from CNS to PNS
-Dendrites and cell body in CNS, axon enters PNS

22
Q

Neuronal Membrane

A

-Made up of two layers of lipid molecules
-Hydrophilic: water attracting
-Hydrophobic: water repelling
-Barrier: water soluble molecules cannot pass through

23
Q

Cations +VE

A

-Sodium (extracellular)
-Potassium (intracellular)

24
Anions -VE
-Chloride (extracellular) -Organic Ions (intracellular)
25
Why do Ions move
1. Concentration gradients via diffusion 2. Electrical Force via electrostatic pressure
26
1. Diffusion
- Ions are subject to the force of diffusion -Move from an area of high concentration to an area of low concentration, down the concentration gradient
27
1. Electrostatic Pressure
- Charges of opposite sign attract -Charges of the same sign repel -Electrostatic pressure
28
Potassium Ions (K+)
Diffusion: -Is highly concentrated in cell -Wants to move out of cell down the concentration gradient, inside the cell becomes more -ve -Electrostatic pressure -Not alot of potassium moves out -Ions will stop moving when opposing forces are at equilibrium
29
Chloride Ions (Cl-)
Diffusion: -Highly concentrated outside cell -wants to move into cell down the concentration gradient Electrostatic pressure: -Inside cell is -ve charged -Wants to move out of cell
30
Sodium Ions
Diffusion - Highly concentrated outside cell -Wants to move into cell down the conc gradient Electrostatic pressure: -Inside of cell is - charged -Wants to move into cell
31
Phases of Action Potential
1. Depolarisation: Inside becomes more +ve 2. Repolarisation: Inside becomes more -ve 3. Hyperpolarisation: more -ve than the rest *Only occurs if threshold is reached (-55mV)
32
Neurotransmitters
-Acetylcholine -Serotonin/ Dopamine -Epinephrine / Adrenaline -Endorphins -GABA -Glutamate
33
Acetylcholine
-Excitatory neurotransmitter -CNS and PNS -Released by neurons in ANS regulating heart rate, blood pressure, gut motility -Plays a role in muscle contractions, memory, motivation -Imbalances linked with Alzheimer's
34
Serotonin / Dopamine
-Monoamines -Inhibitory -Regulates mood, sleep patterns , libido, anxiety -heightened arousal, learning focus, memory -Imbalances include SAD, anxiety, medications
35
Epinephrine / Adrenaline
- Responsible for fight or flight -Stimulates body's response by increasing heart rate, breathing, blood pressure, attention and focus -Excess epinephrine can lead to high blood pressure, diabetes, heart disease -Used to treat anaphylaxis, asthma attacks and severe infections
36
Endorphins
-Peptides, pain relievers -Low levels of endorphins may play a role in fibromyalgia and some types of headaches
37
GABA
-The most common inhibitory neurotransmitter of the nervous system, particularly in the brain -Regulates brain activity to prevent problems in the areas of anxiety, irritability, concentration and sleep
38
Glutamate
-Most common excitatory neurotransmitter -Most abundant neurotransmitter in the brain -Key role in cognitive functions like thinking and learning -Imbalances associated with Alzheimer's disease, dementia and Parkinson's
39
Myelination
-Performed by two types of glial cells: 1. Schwann cells (PNS) 2. Oligodendrocytes (CNS) -Contain fatty tissue called myelin that wraps around neuron axons -Forms insulating coating: Myelin sheath -Oligodendrocyte wraps several axons -Myelinated axons
40
Unmyelinated VS Myelinated
Un: -AP causes passive spread of current -Depolarises adjacent membrane My: - Myelin stops the leakage of ions across membrane -AP only triggered at each node -Saltatory conduction
41
Advantages of Myelination
-Speed, more myelination = faster - Less sodium enters during AP's
42
Reasons for Demyelination
-Stroke -Infections -Immune disorder -Nutritional deficiency -Excessive use of alcohol -Drugs