Muscles and Nerves Flashcards
What are the 3 phases of muscle contraction?
1) Latent Period (between action potential and contraction)
2) Contraction phase (Tension is increasing and cytosolic Ca2+ increasing)
3) Relaxation Period (Tension is decreasing and cytosolic Ca2+ decreasing)
What are the 5 types of muscle?
1) Pennant
2) Fusiform
3) Convergent
4) Parallel
5) Circular
Name the 4 glial cells in CNS and brief function:
1) Astrocytes: Exchange between the blood and the nerve cells
2) Oligodendocytes: Myelination, can myelinate more than one axon at once
3) Microglia: Macrophages
4) Ependyma cells: Dilated cells that secrete cerebro spinal fluid, lining cells
Name the 3 types of neurones:
1) Multipolar : dendritic tree (motor neurones)
2) Uni polar (pseudounipolar): Axon splits into 2, no clear dendrites (Sensory neurones)
3) Bi polar, 2 axons, in sensory structures
What factors affect speed of nerve conductance velocity (NCV)?
1) Extent of Myelination
2) Relative diameter of muscle fibre
What factors affect speed of nerve conductance?
1) Extent of Myelination
2) Relative diameter of muscle fibre
What factors affect strength of muscle contraction?
1) Length of sarcomere (optimum overlap of myosin and actin filaments)
2) Number of/size of motor units stimulated
3) Number of action potentials
Sarcomere H zone?
Only myosin filaments (shortens on contraction)
Sarcomere A band?
Complete length of myosin filaments (stays same on contraction)
Sarcomere I band?
Only actin filaments (shortens on contraction)
Sarcomere Z line? What attaches this to myosin filmanets?
Z line attaches actin filaments together, Giant protein titan (connectin) attaches the Z line to myosin filaments
Sarcomere M line?
Middle of H zone, M lines get closer together on contraction
What are the glial cells in the PNS?
1) Schwann cells: Myelination, can only myelinate one portion of an axon at once
2) Satellite cells: surround cell bodies in ganglia, similar to astrocytes
What are the glial cells in the PNS?
1) Schwann cells: Myelination, can only myelinate one portion of an axon at once
2) Satellite cells: surround cell bodies in ganglia, similar to astrocytes
How are unmyelinated axons supported?
Supported by neighbouring Schwann cells
What are the gaps in myelinated axons called?
Nodes of Ranvier
What are the 2 types of ganglia in the body?
Sensory ganglia (cell bodies of sensory neurones) Autonomic ganglia (cell bodies of efferent neurones: where sympathetic nerves can synapse)
What are ganglia?
Nodular masses of neuronal cell bodies and supporting neuroglia (satellite cells)
What is a bundle of nerve fibres (ie. axons) called?
Fascicle
What is endoneurium, perineurium and epineurium?
Endoneurium: covers indicidual nerve axons
Perineurium: covers a fascicle
Epineurium: covers the whole nerve (made up of lots of fascicles)
Where are the ganglia of parasympathetic fibres (and thus where do they synapse)?
Near or in target tissues
Where are the ganglia of sympathetic fibres (and thus where do they synapse)?
Sympathetic chain
What are the pre ganglionic and post ganglionic neurotransmitters for sympathetic and parasympathetic fibres?
Both preganglionic and parasympathetic post ganglionic = ACh
Post ganglionic sympathetic = NA
What are the types of sensory receptors as defined by location?
Exteroceptors, Interoceptors and Proprioceptors