Basis of Central Nervous System Flashcards
What is the neural tube and how does it form
- Neural tube is an embryonic structure that ultimately develops into the brain and nervous system
- Notochord in mesoderm induces changes to the ectoderm
- Secretes growth factor which causes ectoderm to invaginate
- Invagination breaks off from ectoderm and forms the neural tube
Explain the concept of emergence
- Complex behaviour emerges from the interactions of individual relatively simple units
- Eg. Interactions of water molecules can create a vortex
- Eg. Interactions of different lobes of the brain can create a human mind
Compare CNS and PNS in terms of regeneration, sophistication, myelination, tumours and immunity
- CNS no regeneration, PNS has regeneration
- CNS sophisticated, PNS not
- CNS myelination through oligodendorcytes, PNS through Schwaan cells
- CNS tumours benign and malignant, PSN benign
- CNS immunity through microglia, PNS has immune response
Explain immune privilege in CNS
- CNS also shielded from peripheral immune response by immune privilege
- Do not want inflammation within CNS
- CNS has immunity through microglia cells
Explain ventral/dorsal and rostral/caudal of the brain
- Rostral front of head, caudal back of head
- In the head, ventral is the inferior brain and dorsal is the superior brain
Point to the different parts of the brain
On onenote
State the actions of the midbrain
Eye movements and reflex responses to sound and vision
State the actions of pons
Feeding, sleep
State the role of medulla
- Cardiovascular and respiratory centres
- Contains major motor pathway - medullary pyramids
- Life-threatening if damaged
Explain the concept of decussation
- Fibres cross from 1 hemisphere to opposite side
- Occurs at the medullary pyramid
- Body is controlled by contralateral side of the brain
- Exception is cerebellum where left side controls ipsilateral side of body and vice versa
Define sulcus
A groove in the brain separating adjacent gyri
Define gyrus
- A ridge of fold in the brain
- Increases surface area that is able to fit into skull
Define fissure
Large crack or split between adjacent large areas of the brain
Describe the actions of each lobe of the brain
- Frontal lobe - higher cognition, motor function, speech
- Parietal lobe - sensation, spatial awareness
- (In CNS, motor function always anterior and sensory function always posterior)
- Temporal lobe - memory, smell, hearing
- Occipital lobe - vision
- Cerebellum - coordination and motor learning
What is the optic chiasm
Site where fibres in the visual system cross over
What is the uncus
- Part of the temporal lobe that can herniate and compress the midbrain when intracranial pressure increases
- Located on the inside of the temporal lobe
What are the medullary pyraminds
Location of descending motor fibres
What is the corpus callosum
Fibres connecting the two cerebral hemispheres
What is the thalamus
Sensory relay station projecting to sensory cortex
What is the hypothalamus
Essential center for homeostasis
State the actions of cerebellym and what happens if it becomes damaged
- Involved in coordination of motor function, posture and balance
- Damage leads to poor motor control of ipsilateral side
- No problem with strength of muscles, just fine-tuning movements
- Alcohol affects cerebellum
What does the forebrain consist of
Consists of cerebrum and diencephalon (hypothalamus, thymus)
What does the hindbrain consist of
Cerebellum, pons, medulla
What forms the brainstem
Midbrain, pons, medulla
