Scenario (1) structure and function of neurone Flashcards
cranial nerves
classified as peripheral nerves supply the face
Non-excitable cells
Glial cells- tumours in the brain due to damage
more numerous than neurones 10:1
- support
- protection
- nutrition
what do schwann and oligodendrocytes cells produce
Myeline
CNS glial cells PNS glial cells
X4 in the CNS
- Astrocytes
- Oligodendrocytes
- Microglial
- Ependyma
X2 PNS
- Schwann
- Satilite cells
CNS glial cells
Astrocytes: ⭐️shaped- control exchange chemicals circulatory+nervous system
transfer materials between vascular systems and nueral tissue form the blood brain barrier
Oligodedrocutes: 🟣cells with few processes
synthesise and selectively myelinateneural axons
Microglial: 🟠 few processes
migratory cells that mediate immune response in CNS + PNS (phaocytic role)
Ependyma cells: epithelial cells
Line ventricles (ciliates circulation CSF)
CSF cerebral spinal fluid- protection, nutrition
what is within the CNS
- Grey matter spread over surface= cortex
- cell bodies grouped together= nuclei
- a bundle of axons (whie) that travel along side eachother= tract, lemniscus,fasciculus, capsule
what is within the PNS
cell bodies grouped together= ganglion
bundles of axons= peripheral or cranial nerves
What is Guillain–Barré syndrome (GBS)
Rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. Attacks myelin
- some recover some don’t
- pain
- parasthesia- numbness
MS
Attacks myelin in CNS
Extrafusal muscle fibers
Skeletal standard muscle fibers that are innervated by alpha motor neurons and generate tension by contracting allowing for skeletal movement.
They make up large mass of skeletal (striated) muscle and are attached to bone by fibrous tissue extensions (tendons).
Intrafusal muscle fibers
Highly specialised sensory receptors
Skeletal muscle fibers that serve as specialized sensory organs (proprioceptors) that detect the amount and rate of change in length of a muscle
What is a motor unit
Combination of a single motor neurone and the muscle fibres that it innervates
The axon of an individual alpha motor neurone branches within the target muscle and innervates a number of muscle fibres
What does a motor neurone consist off
Small numbers of muscle fibres in delicate muscles eg hand for precise movements
Large numbers of muscle fibres in postural muscles eg quads
Nerve endings
Either afferent or efferent
Respond to mechanical thermo or chemical stimulation
What are nerve endings called that induce movements
Motor
Efferent nerve endings
Resemble the synapse that occur between neurones
Transmission Is chemical: depolarisation of endings causes a release of a neurotransmitter that acts on receptors in the target cell
In straited muscle both alpha motor neurones (innervate extrafusal muscle) and gamma motor neurones (innervate intrafusal muscle) end at NUROMUSCULAR JUNCTIONS or MOTOR END PLATES
