neuroanatomy Flashcards
What structures are in the PNS?
Cranial nerve (comes out of brain) Spinal nerves Ganglia (dorsal root ganglia)
What structures are in the CNS?
Brain and spinal cord
Describe nerve dendrites, cell body and axons
Dendrites = electrical stimulation
Cell body = integrates signals, generates AP
Axon = signals from body to axon terminals
What are the three areas of the brain based on development ?
Forebrain
Midbrain
Hindbrain
What sections are included in the forebrain?
- Prosencephalon (cerebellum)
2. Diencephalon (Thalamus and hypothalamus)
What sections are in the midbrain?
Mesencephalon
What sections are included in the hindbrain ?
Medulla
Pons and cerebellum
What are sulci and gyri ?
Sulci = infolding of cerebral hemisphere, form valleys between gyri Gyri= ridges of infolding cerebral cortex, the actual tissue
What are nerve nets ?
Simplest form of NS Nerve cells in net-like formation in layers of body wall no central control nerve signals travel in both directions in jellyfish and hydras
Describe the NS in starfish
Centralisation of the NS
Ring of neurones in the centre with bundles of neurones (radial nerves) extending to each arm
What is cephalisation ?
Formation of the primitive brain
Animals with bilateral symmetry ( 2 nerve cords run down body), ganglia, cluster of neurones near head for a more complex system
What are the 4 functional areas of the brain?
Frontal = motor Parietal = sensory Occipital = vision Temporal = auditory
What are the 7 parts of the CNS?
Cerebrum Diencephalon (Brainstem)= Midbrains, Pons, Medulla Cerebellum Spinal cord
What is grey matter?
Cell bodies, major component of CNS
Central in spine, out in brain
What is white matter?
Myelinated axons, connect to different parts of grey
How are the cerebral hemispheres connected?
Corpus callosum and axons travelling between hemi(commissural fibres )
Where do the afferent inputs to the cerebral cortex come from?
ASCENDING info from the thalamus, brainstem, forebrain , hypothalamus
Axons travelling between hemi (commissural fibres )
Info from ipsilateral cortex
What is the cerebral output?
Excitation from pyramidal cells (use excitatory NT eg Glutamate)
Describe the features and functions of the brainstem
- Ascending and descending tracts connect the SC to higher centres ( cerebrum, cerebellum)
- Important in reflex centres, associated with control of rest, heart rate, BP, consciousness
- contain cranial nerve nuclei
What are the functions of the cerebellum ?
Posture Tension of muscles Aids cerebral cortex in planning sequential movements (one movement to the next = smooth) Motor coordination Balance
What are the cerebellar inputs ?
Spinal cord, vestibular system, motor systems in neocortex
What are the cerebellar outputs ?
Vestibular system, brain stem, muscle spindles, motor and pre-motor cortices
How is the CNS protected ?
Bone ( skull and vertebral column)
Meninges
CSF ( cerebrospinal fluid)
What are meninges ?
Connective tissue which encloses the brain, spinal cord and there blood vessels
3 layers = dura, arachnoid, pia
What is the CSF?
Clear free fluid produced by th choroid plexus (ependymal cells )that circulates in the the subarachnoid space
Helps buoyancy
What is the blood brain barrier made of ?
Endothelial cells joined by tight junctions
What is the purpose of the blood brain barrier?
Form glial-limiting membrane around BV and CNS surface
Preventing the diffusion of solutes and fluid into brain and SC
What is the integrity of the blood brain barrier dependent on ?
Astrocyte end feet
What do microglia go ?
- phagocytose cell debris in response to injury
- have to be activated but CNS damage
- release cytokines (help or hinder recovery)
What are purkinje neurones ?
pear-shaped cell bodies
distinctive dendrite tree
receive afferent info
largest cel in cerebellum
What do olgiodendrocytes do?
form myelin sheath around CNS axons
I oligodendrocyte about to myelinate several axons
What do Schwann cells do?
Form myelin health around PNS axons
role in org of connective tissue sheaths around peripheral nerves during development and regeneration
