The Nervous system, tissue and transmission 10,11,12 Flashcards
What is the function of sensory receptors & afferent (sensory) nerves?
To carry information to brain and spinal cord.
What is the function of inter-neurones?
integration and information processing, carried by short interneurons.
What is the function of Motor activity /efferent (motor) nerves ?
Carry signals from brain and spinal cord to glands.
name the structures of the nervous system
spinal chord, sensory receptors, brain, enteric plexuses, ganglia, nerves.
What are the 2 nervous systems in order
1) central nervous system, (CNS)
2) peripheral nervous system (PNS)
What does the central nervous system include?
Brain and spinal chord.
what does the peripheral nervous system include?
all nervous tissue outside CNS. Includes somatic, autonomic and enteric nervous systems.
Explain somatic nervous system (SNS)
sensory neurons in somatic receptors and motor neurons to skeletal muscle.
explain autonomic nervous system (ANS)
sensory neurons from autonomic receptors and motor neorons to smooth muscle, cardiac muscle and glands.
Enteric nervous system (ENS)
sensory and motor neurons of the GI tract and enteric plexuses, motor neurons to smooth muscle, glands, endocrine cells of GI tract.
What is a neuron?
nerve cell, specialised for signal conduction and information processing.
Explain neuroglia cells.
support, nourish, and protect neurons.
neuralgia are critical for maintaining homeostasis of interstitial fluid around neurons.
what are dendrites?
branched structures emerging from cell body - recieve input.
what are axons?
Conducts impulse away from body toward another neuron or effector
where do axons emerge from?
Cone shaped axon hillock.
where are axon terminals found?
at the end of axon with synaptic bulbs.
what does the myelin sheath cover?
axons
what is a myelin sheath?
many layered lipid and protein creating insulations.
what does the myelin sheath do
increases speed of nerve conduction,
what are nodes of ranvier?
gaps in the myelin, they are important for signal conduction.
what can destroy myelin?
diseases such as multiple sclerosis.
where is white matter primarily found?
myelinated axons.
what 5 components is grey matter made of up.
cell bodies, dendrites, unmyelinated axons, axon terminals and neuroglia.
what is the brain cortex (outer layer) made up of?
grey and white matter
where are spinal chord white and grey matter located?
white matter is located externally, great matter is centrally located.
how many types of neuroglia are there?
6 types.
what does the neuroglia cell astrocyte do?
it is a blood brain barrier.
what do the neuroglia cells oligodendrocytes do?
they create myelin in CNS
what do the neuroglia cells microglia do?
act as a defence.
what do the neuroglia ependymal cells do?
produce cerebrospinal fluid.
what do the neuroglia Schwann cells do?
PNS cell support/myelin
what do neuroglia satellite cells do?
found in PNS ganglia.
what are nerve action potentials?
nerve impulses.
what do nerve action potentials require?
a membrane potential - electrical charge difference across cell membrane - like a battery.
what do ion channels do?
allow ions to move by diffusion.
if no action potential then resting cell has..
resting membrane potential - 70mv
talk about the resting membrane potential.
- contains leakage channels- cytosol high in K+ and interstitial fluid high in Na+
- leakage lets K+ through easily and Na+ poorly, inside is negative relative to outside.
*actual RMP depends on relative leakage channels numbers.
what is action potential
series of active events, channels actively open and close.
an initial event is required to reach a voltage threshold of what?
50millivolts.
