Lec 2 Flashcards
What is part of CNS and PNS
CNS = brain and brainstem + spinal cord
- nucleus is part of brainstem
PNS = nerves that extend from spinal CNS
- this includes MOST cranial nerves
what is the node of Ranvier
is the exposed nerve, or gap, between myelin sheaths on the axon
what is a dendrite
branch-like extension that receives input from other neurons
describe how signals transfer between the synaptic cleft
- action potential reach end bulb
- causes influx of Ca2+ ions into bulb
- Vesicles containing neurotransmitter go to end of bulb and release into synaptic cleft via exocytosis.
- Neurotransmitter defuse across cleft and bind to ligand gated channel.
- Cause ligand to open so Na+ influx (or other ions) occur changing membrane potential within the postsynaptic neuron
what is a commissure
A bundle of nerve fibers (axons) that connects corresponding regions on the left and right sides of the central nervous system (CNS).
allows communication between the sides.
Why are some parts of CNS white, and others grey?
Which parts of brain and spinal cord are white and grey matter?
Function of grey/white matter?
Differ in colour due to myelination. Myeline is a fatty substance that insulates nerves. Parts of CNS that are more myelinated appear more white.
- In brain: outside is grey matter ( cerebral cortex), inside is white matter (sub-cortex/subcortical structures)
- In spinal cord: inside is grey matter, outside is white matter.
In brain, grey matter processes information while white matter transmits it. In spinal cord, white matter is on outside while grey is on inside because its job is more to relay information. The grey matter in the spinal cord processes some reflexes that don’t need the brain.
True or false, cell bodies and dendrites connected together are just called nuclei
False - they have many names depending on function and place (nuclei, cortex, laminae etc.)
axons together also have many names (T/F)?
true (nerves, white matter, fibres, tracts, commissure etc.)
Projection fibres. What are they and what do they do? What looks like?
- Run from brain cortex to brainstem and spinal cord
- looks like a fan
Commissural fibres. What are they and what do they do?
- connect brain hemispheres together
Association fibres. What are they and what do they do?
- connect the cortical areas within a hemisphere
difference between gyrus, fissure, sulcus,
Gyrus = fold/ridge (outside)
Sulcus = inside of fold/groove
Fissure = deep sulcus (often divides regions of the brain)
what are all the lobes of the brain + 3 other key parts
- frontal
- temporal
- parietal
- occipital
- limbic lobe (runs deep to frontal, temporal parietal, and surrounds corpus callosum)
- cerebellum
- brainstem
- corpus callosum
what is the anatomical region where the medulla oblongata (the lowest part of the brainstem) transitions into the cervical spinal cord called.
cervical medullary junction
What is the thalamus (describe).
What do both thalami form?
What do?
- egg shaped structure at top of brainstem (but is not part of brainstem)
- form diencephalon
- relays almost all sensory info
- motor integration (tune movements)
- consciousness
- memory
What connects the sides of the thalamus?
Inter-thalamic adhesions
These are white matter connections between sides of thalamus (there is one thalamus per brain hem)
What are the key parts of the brainstem (name 3)
- midbrain
- lies between thalamus and pons.
- visual and auditory processing
- eye movement coordination and some reflexive responses - pons
- middle part of brainstem
- coordinate movement and balance
- regulate breathing
- process sensory info from the face. - medulla
- lowest part of brainstem
- autonomic functions like heart rate, blood pressure, breathing
- control cough, swallow, vomit reflexes.
what are the layers of protection for the brain (list 5)
- Skin
- Skull
- Dura mater
- arachnoid mater
- Pia mater
What does PAD mean when remembering brain structures.
Pia mater
Arachnoid mater
Dura mater
- Pia =innermost, Dura = outermost
What are the meninges
3 protective layers that encase the brain and spinal cord provide cushion and protection (Layer=PAD)
Describe dura mater and parts
- Outermost layer of meninges.
- consist of two layers, periosteal, and meningeal
- periosteal - adheres to inside of skull
- meningeal - fuse to periosteal layer except where extends inwards to separate hemispheres (falx cerebri), and cortex from cerebellum (tentorium cerebelli).
name the layers.
- separates brain hemispheres.
- separates occipital from cerebellum
- Falx cerebri
- tentorium cerebelli
