L.3 Flashcards
What is neurulation
neural plate folds to form the neural tube
When does neurulation happen
early embryonic development (first 3 weeks)
What is the neural tube
precursor of CNS
Outline how neurulation happens
- mesoderm cells form notochord
- notochord induces thickening of ectoderm cells
- forms neural plate
- neural plate folds inwards into neural tube
What are neural crest cells
they migrate into PNS to differentiate
Name 2 types of neural tube defects
- spina bifida
- anencephaly
What is the cause of anencephaly
improper closure of the anterior neural tube to close
What are the 2 types of spina bifida
- Spina bifida occulta
- Spina bifida cystica
What is the overall cause of Spina bifida
improper closure of posterior neural tube to close
Consequence of spina bifida occulta
no visible sac & less severe
Consequence of spina bifida cystica
visible sac (meninges out) & severe
What are the 3 primary brain vesicles
- prosencephalon
- mesencephalon
- rhombencephalon
What are the secondary brain vesicles
- prosencephalon: telencephalon & diecephalon
- mesencephalon stays the same
- rhombencephalon: metencephalon & myelencephalon
What does the telencephalon represent
cerebral hemisphere
What does the diencephalon represent
thalamus & hypothalamus
What does the mesencephalon represent
midbrain
What does the metencephalon represent
pons and cerebellum
What does the myelencephalon represent
medulla
What are flexure developments
when the primary vesicles bend to develop the secondary brain vesicles (the space is limited) – causes flexures
What are the 3 main flexures
- cephalic
- cervical
- pontine
What is the spinal cord made of
white and grey matter
What is white matter:
myelinated axons
What is grey matter
neural cell bodies
What are the main functions of the spinal cord
- carries sensory information to the brain and motor information from the brain
- autonomic functions (reflexes)
Where does the spinal cord end
conus medullaris (below L1)
What is the lumbar cistern
space below conus medullaris filled w/ CSF & where cauda equina is located
What is the conus equina
dorsal and ventral nerves exit below conus medullaris (supply the lower body)
What is the terminal filum
anchors the conus medullaris to coccyx
what is the cervical enlargement
provides nerves to upper limbs
what is the lumbosacral enlargement
provides nerves to lower limbs
why are the cervical and lumbosacral enlargement bigger
there are more nerves
How many pairs of nerves branch from spinal cord
31
how is blood supplied to spinal cord
- anterior and posterior spinal arteries
- segmentary spinal arteries
How is the spinal cord protected
- dura = outermost layer of spinal cord
- it runs via a vertebral canal
What is the function of the brainstem
- relay centre for sensory and motor information
- control ANS + vital involuntary functions (CVS, breathing, vomiting, digestion, blood pressure)
What are the 3 main regions of the brainstem
- medulla
- pons
- midbrain
What is the function of the medulla
controls vital autonomic functions
What are 2 important strictures of medulla
- pyramid and olive
What is the function of pyramid in medulla
controls all skeletal muscles
What is the function of olive in medulla
relay centre between medulla and cerebellum
What is the function of pons
relays information to brainstem and cerebellum
What are the 3 main structures of pons
- transverse fibres
- cerebellar peduncles
- reticular formation
What are transverse fibres
- they help send messages between the pons and cerebellum
- make up cerebellar peduncles
What are cerebellar peduncles
- made of transverse fibres that connect pons to cerebellum
What is the reticular formation
involved w/ sleep and motor function
What is the function of midbrain
act as a relay station for visual and auditory information
Where is the superior and inferior colliculus found
midbrain
What is the function of the superior colliculus
- processes visual information and eye movement
What is the function of inferior colliculus
- processes auditory information
Where is the main structures found in the midbrain
- superior & inferior colliculi
- substantia nigra
- red nucleus
- cerebral peduncles
What is the function of substantia nigra
produces dopamine & motor coordination
What is the function of red nucleus
motor coordination
What is the function of cerebral peduncles
carry motor signals
What is the function of the cerebellum
- posture
- coordinating & planning limb movements
- controls eye movement
Where are the cerebral hemispheres found
forebrain
what is the function of cerebral hemispheres
coordination and balance
How is the cerebellum organised
into lobes (3)
What are the 3 lobes of cerebellum
- anterior
- posterior
- flocculonodular
What is the function of anterior lobe
involves in posture control
What is the function of posterior lobe
coordination & planning of limb movements
What is the function of flocculonodular lobe
involved in eye movement control
What connects the the left and right hemispheres of cerebellum
vermis
What are features of cerebellum
- highly folded
What is the function of the thalamus
- relays sensory information to cortex (except olfactory)
- involved w/ sleep, memory & consciousness
What joins the 2 thalami together
thalamic adhesion
What is the function of the hypothalamus
- involved in homeostasis
- coordinates ANS and endocrine system
What 2 glands are near the hypothalamus
- pineal gland (produces melatonin)
- pituitary gland (endocrine gland)
