Gross Neuroanatomy Flashcards
What is the role of astrocytes?
- Fill the space between neurons
- Regulate the chemical content of the extracellular space which could interfere with the function of the neurons.
- Migrate to sites of injury
Role of Myelinating Glia (Oligodendrocytes & Schwann cells)
What can happen if these cells are damaged?
- Provide layers of membrane that insulate the axons.
- Damage = multiple sclerosis
Axons become demyelinated and neurons begin to die. Dysarthria, swallowing difficulties and high level cognitive difficulties
Soma (cell body)
- Integrative decision-making
- Filled with cytosol
- Contains DNA
Cytoskeleton
and Disease of the Cytoskeleton
- Microtubules: transmitting messages from dendrite - axon
- Microfilaments:
- Neurofilaments: mechanically strong, hold axon together
Alzheimer’s disease - microtubules fall apart because Tau proteins (that hold microtubules together) detach and tangle.
Axon
Very important role in information exchange:
- Releases neurotransmitter to synaptic cleft
Dendrites
Receive message from synapse, transmit message to the cell body. Well connected neurons will have MANY dendritic spines
Outermost protective layer
Dura mater - tough layer of fibrous tissue
Middle protective layer
Arachnoid layer - thin sheet of connective tissue
Innermost protective layer
Pia mater - moderately tough membrane that clings to the surface of the brain
Differences between the CNS and the PNS
CNS is the brain and spinal cord. PNS is all other neural pathways in the body.
The PNS relays information to (sensory neurons) and from (motor neurons) the CNS.
Divisions of the PNS
Somatic Nervous System - controls all VOLUNTARY body functions
Autonomic Nervous System - controls INVOLUNTARY functions e.g. breathing, heart rate, digestion.
Divisions of the ANS
Sympathetic Division - “fight or flight” responses (increased heart rate, blood pressure etc)
Parasympathetic Division - “rest and digest” functions
Cerebellum
“Little brain” at the rear base of cerebrum.
Controls the coordination of motor processes
Brainstem
Controls important survival reflexes - heart rate, breathing, swallowing, sleep.
What is the role of the frontal lobe?
Performs “executive” functions, such as decision-making.
Contains primary motor cortex
Motivation
Personality
What is the role of the temporal lobe?
Interpreting sounds and language
Contains the primary auditory cortex
Memory (contains the hippocampus)
What is the role of the parietal lobe?
Processing tactile sensory information
Contains the somatosensory cortex
What is the role of the occipital lobe?
Interprets visual stimuli/information
Contains the primary visual cortex
What connects the left and right hemispheres?
Corpus collosum - allows communication between the two hemispheres
Structural changes characteristic of MS
Destroys myelin - therefore action potential slows/stops as it travels along the axon. Neuron eventually dies. Muscle weakness,
Visual Neglect
Damage to the parietal lobe in the right hemisphere. Disrupts ability to pay attention to things on the left side of their visual field
Frontotemporal Dementia
Overt change in the individual’s personality
Irritability, withdrawal, obsessions.
Often NO CHANGE TO MEMORY
Which lobe enables us to recognise objects/faces by sight?
Temporal lobe
Limitations of localisation theory
Too simplistic - many areas of the brain contribute to a single function (especially higher order cognitive functions).
- Localisation theory doesn’t fully explain the DIVERSITY of presentation of clients with damage to the same area
