Gross Anatomy and Localisation of Function Flashcards
Cell body
Most prominent part of cell
Filled with cytoplasm and cytosol
Contains nucleus, RER, SER, golgi apparatus, mitochondria
Neuronal membrane
Barrier that encloses the cytoplasm
Studded with proteins; pump substances in/out of cell, regulates which substance gain entry to cell
Structure of discrete membrane influences neuronal function
Cytoskeleton
Not static
Internal scaffolding of neuronal membrane
Made of microtubules, microfilaments and neurofilaments
Cytoskeleton - microtubules
Protein transfer down the axon
Cytoskeleton - microfilaments
allows cell to change shape
Cytoskeleton - neurofilaments
Mechanically strong
Holds skeleton together
Alzheimers and the Cytoskeleton
Loss of brain function as a result of damage to the cytoskeleton
- Shinkage: atrophy occurs
- Tau proteins become defective (braids unwind); neurofibrillary tangles
Severity of alzheimers correlates with number, distribution of neurofibrillary
Axonal Structures
Axon hillock (beginning) Axon proper (middle) Axon terminal (end)
Axon vs Soma
ER doesn’t extend into axon
Unique protein composition
Dendrites
Number of dendrites determines number of synapses that can be formed
- collect info from many neurons
- more synapses = more info to process, integrate
Glia Cells
Astrocytes, oligodendrocytes, ependymal cells, microglia
Astrocytes
Fills space between neurons
Regulate chemical content if extracellular space (can interfere with function of the neuron)
Myelinating glia
Oligodendrocytes (CNS) and schwann cells (PNS)
Oligodendrocyte/Schwann cells
Provides layers of membrane insulating the axon
Multiple Sclerosis
Progressive neurological disease that destroys myelin
Impacts on conduction
Eventually causes the neurons to die
= muscular weakness, tremor, impaired coordination, visual problems
Ependymal Cells
Lines the fluid filled ventricles
Plays a role in cell birth and migration during brain development
Microglia
Function as phagocytes
Layers of the Spinal cord
Skull, dura mater, arachnoid layer, pia mater, subarachnoid space
Subarachnoid hemorrhage
Bleeding into subarachnoid space
Can either occur spotaneously or caused by trauma
Ventricles
Creates CSF Carries nutrients to the brain Removes debris Provides cushioning Provides buoyancy
Hydrocephalus
Obstruction within the ventricular system
Epidural Hematoma
bleeding between the dura mater and the skull
Subdural hematoma
Bleeding between the arachnoid mater and dura mater
Ventricle functioning impaired; not as buoyant, not as efficient in producing CSF/removing debris, affects surrounding tissue
Cerebrum
Major structure of the forebrain
Consists of two identical hemisphere
Cerebellum
Coordination of motor, other mental processes
Brain stem
Central structures of the brain
Hind brain, mid brain, thalamus, hypothalamus, pons, medulla
Responsible for unconscious behaviour
Pons
hearing, equilibrium, taste, facial sensation, sleep
Locked in syndrome - extremely paralysed, affects all aspects, cognition intact
Medulla
breathing, heart rate, blood pressure, swallowing
Brainstem stroke
affects motor pathways (dysarthria, swallowing)
Gyrus
Small bump; folding of cerebral cortex
Sulci
Groove; found in neocortex, cerebellum
Responsible for large surface area
Fissure
Very deep sulcus
Internal Brain Features
Grey matter (cell bodies, nuclei) White matter (myelinated axons) Ventricles
Corpus Callosum
Fibre system connecting the two cerebral hemispheres
Allows communication between the two hemispheres
Dense bands of fibres/white matter sheets
Bands of axons
200 million fibres
Four Ventricles
Two lateral ventricles
Third ventricle
Fourth ventricle
Occipital Lobe
Cortical processing of visual info
Pure alexia without agraphia
Occipital lobe affected
Total inability to read, writing isnt affected
Temporal lobe
Includes auditory cortex and wernicke’s area (important for language comprehension)
Medial temporal cortex
Hippocampus, memory, alzheimers/amnesias
Prefrontal cortex
Largest region of the brain
Supports cognitive functions (planning, inhibition, problem-solving, organisation, impulse control, adjust/regulate behaviour)
Issues = depression, schizophrenia
Primary Motor Cortex
Volitional non-reflexive mocememnt
Broca’s Area
Speech production
Comprehension-focussed
Frontotemporal dementia
Apathy, withdrawal, irritability, self-centredness, difficulty reasoning,lack of judgement, emotionally distant, criminal behaviour, obessions and compulsions, false thoughts and delusions, overeating and food fads, diminished social tact
Parietal Lobe
Temperature, touch, awareness of body in space, critical for swallowing
Parietal stroke - not integrating touch, visual neglect
Association cortex
Higher order functions
Integrating info
