Nervous System Flashcards
Structure and function of a neuron
Dendrites receive impulses, cell body integrates information and produce neuro transmitters axon transmits impulse away from the cell body, synapse is where a neuron meets another cell
Dendrites to cell body to axon to synapse with another cell
Neurons
Receive and transmit impulses, glial cells surround and support neurons,
What is the function of the myelin sheath?
Formed from a flat cytoplasmic extensions of glial cells wrapping around axon many times, these many layers of lipid pm insulate axon and prevent ion flow in these regions, gaps between areas of the sheath are nodes of ranvier and ion flow can only occur here.
Polarization
The plasma membrane of a neuron at rest in polarized positive outside and negative inside
Nerve impulses or action potentials
Neuron at rest pos outside neg inside receives stimulus, sodium gates open and sodium rushed into the cell inside becomes pos and out neg the reversal in charge is called DEPOLARIZATION this leads the generation of action potential down the axon
After depolarization….
Sodium gates shut, sodium can’t enter, potassium leaves, sodium potassium pump go to work leading to REPOLARIZATION pos outside neg inside.
What is Saltatory conduction?
Occurs on myelinated axons, ions can’t cross pm where myelin insulates so ap jumps from node of r to node of r.
Synaptic cleft
A very small space between the cells, where neuro transmitters cross.
Central nervous system
Include the brain and spinal chord
Peripheral nervous system
All of the outlying nerves
What are the two branches of the peripheral nervous system?
Somatic ns sends info from the skeletal muscles, autonomic ns send s info from organs and glands. Autonomic has two branches sympathetic and parasympathetic.
Sympathetic vs parasympathetic
Regulate the activity of glands heart and smooth muscle, have opposite effects in the body, sympathetic ns prepares body for flight or fight and para ns prepares body for rest and digest
Flight or fight reaction
Increases heart rate, shunts blood from skin, viscera to skeletal muscles and heart, dilates pupils, inhibits digestive and urinary systems, dilates bronchioles, inhibits salivary glands, stimulates sweet glands, stimulates muscles on hairs.
The brain
Midbrain reflexes to visual and audio input, pons bridges midbrain to other parts brain stem, medulla oblongata regulation of breathing heart rate and blood pressure, corpus collosoum connects right and left hemispheres,lambic system emotions and memories, cerebellum controls balance and movements, hypothalamus hunger sex drives body temp
Spinal chord
Enclosed and protected by the vertebral column, same three layers on meninges as brain, white matter encloses butterfly of gray matter, central canal with CSf in the middle
