Nerves Flashcards
Subdivision of nervous system
CNS and PNS
CNS
Brain and spinal cord
PNS
Somatic and Autonomic
Somatic
Voluntary control ( skeletal muscle)
Autonomic
Sympathetic and Parasympathetic
Brain
Meninges Gyrus and sulcus Cerebellum Cerebrum Diencephalon Brainstem
Meninges
Dura
Arachnoid
Pia
Gyrus
Folds
Sulcus
Grooves
Cerebrum
Frontal
Occipital
Parietal
Temporal
Diencephalon
Hypothalamus- homeostasis
Thalamus- sensory
Brainstem
Mid-brain
Pons
Medulla Oblongata
Spinal cord has ____ pairs of spinal nerves
31
\_\_\_ cervical \_\_\_\_ thoracic \_\_\_\_\_ lumbar \_\_\_\_ sacral \_\_\_\_\_ coccygeal
8 12 5 5 1
Grey Matter=
Dorsal horn
Ventral horn
Lateral horn
Neuron structure
Cell body (soma)
Dendrites (receive information)
Axons (sends action potential)/(release transmitter)
Types of neuron
Glia- astrocytes, oligodendrocytes
Microglia- phagocytic
Resting Membrane Potential
-70mV
What maintains the RMP
Leaky channels
Na+/K+ pump
Large intracellular -ve charged molecules
Equilibrium potential
The membrane potential at which the electrical gradient is exactly equal and opposite to concentration gradient
Hyperpolarisation
More negative
Depolarisation
More positive
Action Potentials
Transmit signals over long distances
Graded Potential
Decides when an action potential should be fired
Resting membrane potential
keeps cell ready to respond
Action potential process
- cell stimulated up to threshold (graded)
- depolarisation
- repolarisation
- hyperpolarisation
- back to resting potential
Graded Potential
Generated by ligand gated channels End plate potential at NMJ Can occur due to hyperpolarisation or depolarisation Decremental Non-propagated Amplitude determines stimulus
Fast EPSP (ionotropic)
Release of glutamate
Surge in Na+
Depolarisation
Fast IPSP (ionotropic)
Release of GABA
Cl- cells enter
Hyperpolarisation
Slow EPSP
Release of glutamate
Binds to G protein
Closes some leaky K+ channels
Prevents cell returning to RMP
Slow IPSP
Neurotransmitter binds to G protein
Activates G protein and causes K+ ions to flow out of cell
Which leads to hyperpolarisation
Action Potential
Have threshold They are all or none Voltage gates ion channels Cannot encode amplitude only frequency Cannot summate self-propagate Have refractory period
Compound Action Potential
Graded
Summation of many APs from different axons (myelinated and unmyelinated)
Fastest conducting axons
Ia Muscle spindle
Slowest conducting axons
IV pain and heat
tetrodotoxin
blocks Na+ channels and blocks AP
Joro spider toxin
blocks Ca+ channels and stops transmitter release
Botulinum toxin
disrupts the release of transmitter
Curare
blocks Ach receptors and prevents end-plate potential
anticholinesterase
blocks removal of acetylcholine
