Anatomy (nervous system) Flashcards
two communication and control systems that keep things working properly
nervous system
endocrine system
how do they carry their messages
they use chemicals to carry their message but they do it by different means and one different timescale
nervous system’s chemical messengers are called
neurotransmitters and they are only produced by neurons (nerve cells)
neurotransmitters
produced by neurons, travels short distances across synapses, allows system to react quickly
synapses
gap/ junction between two neurons or between a neuron and its target cell
chemical messengers of the endocrine system called:
hormones
Hormones
secreted directly into bloodstream, where they travel a long distances to reach their targets, body reacts more slowly to changes
structurally the nervous system has two main divisions:
central nervous system (CNS)
peripheral nervous system (PNS)
CNS
central nervous system
composed of the brain and spinal cord
PNS
consists od cordlike nerves that link the central nervous system with the rest of the body
3 main activities
sensory functions
integrating functions
motor functions
‘neuro’
refers to the nervous system
‘logos’
means the study of
neurons
nerve cells
are the basic, functional unit of the nervous system, high requirement for oxygen, cannot reproduce but can regenerate cell processes (this can take years and can only happen if the nucleus is safe), have support and protection from neuroglia cells vary in appearance for different parts
glial
greek meaning glue
central cell body
soma or perikaryon
cell processes
dendrites and axons
dendrites
receive stimuli or impulses form other neurons and conduct this stimulation to the rest of the body
short, numerous, multi branched
referred to a afferent processe because they conduct impulses towards the cell body, may serve as sensory receptors that receive or sense stimuli such as heat, cold, touch, pressure, stretch, or other physical changes form the inside or the outside the body
axons
conduct nerve impulses away form the cell (efferent) body towards another neutron or effector cell,
short,long process,
maybe covered with myelin (white matter), nerve fibres: bundles of axons
myelinated axons
myelinated axons conduct impulses faster than those with no myelin,
central nervous system (CNS)
- composed of brain and spinal cord
* found along central axis of body
peripheral nervous system (PNS)
- components extend away from the central axis outward
- cranial nerves
- spinal nerve
afferent nerve fibers
- conduct impulses toward CNS
* also called sensory nerves