NEURO MID-SEM EXAM

Neuroscience Mid-sem exam weeks 1-5

what are the two main divisions of the nervous system?

Central nervous system (CNS) and peripheral nervous system (PNS)

what structures make up the CNS

brain (cerebrum, cerebellum, brainstem) + spinal cord

main function of PNS

transmits sensory information to the CNS and controls motor functions.

what are the two divisions of the PNS

somatic nervous system and autonomic nervous system

what does the somatic nervous system control

voluntary movements of skeletal muscles and reflex actions.

what does the autonomic nervous system control

involuntary bodily functions such as heart rate, digestion, and respiratory rate.

what are the two divisions of the autonomic system

sympathetic and parasympathetic nervous systems.

what is the function of the sympathetic system

fight or flight repsonses

what is the function of the parasympathetic sysetm

rest and digest

what does rostral mean

anterior (front)

what does caudal mean

inferior/posterior (back/bottom)

what does dorsal mean

superior (top)

what is the cerebral cortex

outer layer of the cerebrum made of grey matter (cell bodies)

what is grey matter

a collection of neuron cell bodies

What is white matter?

A collection of axons

What are gyri?

Raised folds of the cortex

What are sulci?

Grooves between gyri

Why are gyri and sulci important?

Increase surface area → more neurons → greater processing

What does the longitudinal fissure separate?

Left and right hemispheres

What does the central sulcus separate?

Frontal and parietal lobes

What does the lateral sulcus separate?

Temporal lobe from frontal/parietal lobes

What are the functions of the frontal lobe?

Motor function, speech production, executive function, behaviour

What are the functions of the parietal lobe?

Sensory processing and spatial awareness

What are the functions of the temporal lobe?

hearing + memory

What are the functions of the occipital lobe?

vision

Where is the primary motor cortex located?

precentral gyrus (frontal lobe)

What is the function of the primary motor cortex?

voluntary movement

Where is the primary somatosensory cortex located? function?

Postcentral gyrus (parietal lobe). Processes touch, pain, temperature

Where is the primary visual cortex?

occipital lobe

Where is the primary auditory cortex?

temporal lobe

Where is Broca’s area located? function?

frontal lobe. Speech production

Where is Wernicke’s area located? Function?

Temporal/parietal region. Language comprehension

What is Brodmann area 4?

primary motor cortex

What are areas 1,2,3?

somatosensory cortex

What is area 6?

premotor cortex

What are areas 44 & 45?

Broca’s area

What is area 22?

Wernicke’s area

What are projection fibres? Example?

Connect brain to spinal cord (ascending & descending). Internal Capsule

What are commissural fibres? Example

Connect left and right hemispheres. Corpus Callosum

What are association fibres?

Connect regions within the same hemisphere.

What connects Broca’s and Wernicke’s areas?

Arcuate fasciculus

What does “diencephalon” mean?

Through brain”

Where is the diencephalon located?

Between hemispheres, above brainstem, around 3rd ventricle

What are the four parts of the diencephalon?

Thalamus, epithalamus, hypothalamus, subthalamus

What is the main function of the thalamus?

Relay station for sensory and motor information

What relays hearing?

Medial geniculate nucleus

What relays vision?

Lateral geniculate nucleus

What is the main structure of the epithalamus? Function?

pineal gland. regulates circadian rhythm (melatonin)

What is the main role of the hypothalamus?

homeostasis: Temperature, hunger, thirst, BP, emotions, hormones

Which gland does the hypothalamus control?

pituitary gland

What is the function of the subthalamus?

Movement regulation (part of basal ganglia)

What is the function of the hippocampus?

Memory formation and spatial navigation

What happens if the hippocampus is damaged?

Cannot form new memories (anterograde amnesia)

What is the function of the amygdala?

Emotion (fear, anxiety, rage)

Which brain areas could explain motor + speech + emotional changes?

Frontal lobe, Broca’s area, limbic system, thalamus

What are common causes of these symptoms?

Stroke, tumour, neurodegenerative disease

What are the 12 cranial nerves in order?

CN I – Olfactory
CN II – Optic
CN III – Oculomotor
CN IV – Trochlear
CN V – Trigeminal
CN VI – Abducens
CN VII – Facial
CN VIII – Vestibulocochlear
CN IX – Glossopharyngeal
CN X – Vagus
CN XI – Accessory
CN XII – Hypoglossal

What does sensory (afferent) mean?

Information traveling to the brain from skin, muscles, and joints

What does motor (efferent) mean?

Information traveling from the brain to muscles

What is the function of CN I?

smell

Is CN I sensory or motor?

purely sensory

CN I ?

Olfactory nerve - smell

CN II

Optic - Vision

CN III

Oculomotor - eye movements: raises eyelids, pupil constriction

CN IV

Trochlear - moves eyes inward + downward

CN V

Trigeminal - facial sensations + mastication

CN VI

Abducens - moves eye outward (abduction)

CN VII

Facial - facial expressions taste

CN VIII

Vestibulocochlear - hearing (cochlear) + balance (vestibular)

CN XI

Glossopharyngeal - taste (posterior 1/3 of tongue), swallowing, saliva production

CN X

Vagus - swallowing + speech: controls heart, lungs + digestion. parasympathetic regulation of organs

CN XI

Accessory - shoulder + neck movement

Hemorrhagic Stroke

Occurs when a weakened blood vessel in the brain ruptures, causing bleeding into or around the brain tissue

Ischemic Stroke

Blood clot blocks an artery supplying blood to the brain, causing rapid brain cell damage due to lack of oxygen to the brain

Transient Ischemic Attack (TIA)

A temporary blockage of blood flow to the brain that lasts a few minutes to hours

Intercerebral hemorrhage (ICH)

type of hemorrhage stroke. blood vessel ruptures inside brain

Subarachnoid Stroke (SAH)

Between brain and skull, vessel ruptures on brain surface

Thrombotic Stroke

Type of ischemic stroke. A blood clot (THROMBUS) forms directly inside an artery applying the brain

Embolic Stroke

A clot or debris forms elsewhere (usually heart) + travels to the brain and gets stuck in a smaller artery

Stroke Risk Factors

• High blood pressure

• High cholesterol levels

• Obesity

• Diabetes

• Smoking

Relapse-Remission MS

Characterised by:

• Relapses (flare-ups) → new or worsening symptoms

• Remissions → partial or complete recovery

Secondary Progressive MS

Characterised by:

• Gradual worsening of disability

• Fewer or no clear relapses

• Starts as RRMS → becomes steadily progressive

Primary Progressive MS

Characterised by:

• Steady progression from the beginning

• No clear relapses or remissions

• symptoms slowly worsen over time

Progressive-relapsing MS

Characterised by:

• Progressive disease from onset

• Occasional relapses

• Always worsening + sudden flare-ups

Multipolar Neurons

• Many dendrites + one axon

• Most common type

Function:

• Mainly motor neurons

Unipolar Neurons - Pseudounipolar

• One process that splits into two

Function:

• Sensory neurons

Bipolar Neurons

• One dendrite + one axon

Found in:

• Special senses:

  • Retina (vision)

  • Olfactory system (smell)

x-ray

• Uses small amounts of ionising radiation that passes through the body

• Image is created by differential absorption of x-rays by tissues

  • Dense tissues (e.g. bone) appear white; air and soft tissues appear darker

Computer Tomography (CT)

• uses rotating x-ray beams to measure tissue density and reconstruct cross-sectional and 3D images

• Image contrast reflects density

  • Bone/metal = white

  • Air/CSF = black

  • Brain = light grey

Magnetic resonance Imaging (MRI)

• Uses a string magnetic field and radiofrequency pulses to align and excite hydrogen protons in tissue

• Image contrast is based on proton relaxation times which vary across tissues ( e.g. water vs grey matter)

• Provides superior soft tissue resolution → preferred for tumours, multiple sclerosis, inflammation, and pituitary lesions

 

Diffusion Tensor Imaging (DTI)

• An MRI-based technique that visualises white matter structure

• Measures directional diffusion of water around bundles of axons

• Water diffuses along axons but is restricted across axons by membranes and myelin

• Diffusion patterns are reconstructed into #D maps of white matter tracts

• Used to study neurological conditions (e.g. multiple sclerosis, traumatic brain injury) and to assess neural pathway changes with surgery or rehabilitation (e.g. corticospinal tract changes after constraint, movement therapy)

Cerebral Angiography

• Three-dimensional reconstructions of the blood vessels using either MRI or CT

• Maps blood supply

• Screen for carotid stenosis, aneurysm (dilation of the wall of an artery or vein) and abnormal connections between arteries and veins

Types of Functional Imaging: Functional Magnetic resonance Imaging (fMRI)

Functional Magnetic Resonance Imaging (fMRI)

• Increase in neural activity while performing a task causes an increase in blood flow and oxygen metabolism

• fMRI measures neuronal activity by detecting changes in oxygenated blood flow (grey matter)

Types of Functional Imaging: Positron Emission Tomotgraphy (PET)

• PET involves the injection of radioactive isotopes

• Detectors measure the gamma rays as they travel through the cerebral vasculture

• PET is able to measure blood flow, glucose metabolism, and oxygen consumption

• Ability to measu

Cells in PNS

Schwann Cells

Cells in CNS

Oligodendrocytes

Neuroplasticity Principle: Use it or lose it

Long Term Depression: synapse weaken or are lsot when not used

Neuroplasticity Principle: use it + improve

Long term Potention. Repeated use strengthens specific neurons + brain circuits

Neurpolasticity Principle: Specificity

The brain changes in direct response to the type of training being performed

Neuroplasticity Principle: Salience

learning is stronger when the experience is meaningful or important: client centred practice + more likely for improvement