Nervous System Flashcards
Nervous system division
Central and peripheral
Pressure receptors vary
in number around the body,
Less pressure receptors means
less messages
NS primary functions
sensory input, integration, motor output, controls all other body systems
CNS functions
the coordinator, it makes sense of the messages it receives from PNS,
CNS coordinates repsonses by
muscle and glands
Cns made up of
brain and spinal cord
PNS made up of
bundles of neves that branch off brain and spinal cord
PNS coordinates responses by
relaying meesages between sense organs and the CNS
Nervous tissue is
very concentrated in cells
Neurons are specalised cells that send and receive
electrical messages across the body
Neuron messages pass in the form of
one way nerve impulses
Neurons consist of:
cell body, dendrites, axon, myelin sheath,
Cell body
where the nucleus is located similar to a regular cell
Dendrites
branches off the nerve (receiver)
Axon
Thread like structure that carries impulses to other nuerons,
Myelin Sheath
fatty layer that insulates axon and dendrites to prevent signals from crossing, increases speed
Types of neurons
three (interneurons, motorneuron, sensory neurons)
motor neurons
transmit messages from CNS to effectors, connect directly to muscle tissue
sensory neurons
specialised receptors (to stimuli like heat or light) transmit messages from receptors to the CNS, connect directly to sensory receptors
Interneurons
transmit messages from sensory neurons to motor neurons and to brain, involved in reflex action
Synapses are:
the meeting point between two neurons
Synapses work:
action potential releases chemicals, vessicles transport to receptors, triggers new electrical signal
Presynpatic and postsynaptic cleft is
sender and receiver of chemical signals
