Nervous System Flashcards
Functions and part of motor neuron
dendrites-receive signals to deliver to cell body
cellbody- site of neuron metabolism
axon- carries signals away from dendrites
node of ranvier-allows impulse to jump from node to node
sensory neuron vs motor neuron
sensory sends signal from pns to cns, motor cns to pns
name all types of neurons
association (interneuron), motor, and sensory
Membrane potential
High Na low K on outside, High K low Na inside
how is membrane potential achieved
Active transport of sodium through NaK pump. For every 2 K pumped in, 3 Na is pumped out.
homeostasis
where constant internal environment is maintained despite changes in external environment
5 properties common to all control systems
limit, energy requirement, error, feedback, overshoots
factors that influence intensity of a sensation
amount of neurons stimulated, size of axons- diameter, if larger will travel faster, frequency of stimulus
refractory period
recovery time required before a neuron allows another action potential to occur (occurs during depolarization)
Glial cells
cells that support the neurons, outnumber neurons
types of neurons and functions
sensory- transmit impulses from sensory receptors to the interneurons.
interneurons- found in the brain and spinal cord. Act as link between sensory and motor neurons.
motor neurons- conduct impulses from interneurons to effectors(muscle)
difference between white and grey matter
myelinated neurons form white matter while unmyelinated form grey ‘H’
where does action potential occur
in node of ranvier of myelinated neurons
when does the sodium gate open
during depolarization (flows in)
when does the potassium gate open
during repolarization (flows out)
Saltatory conduction
conduction of a impulse along a myelinated neuron
neuromuscular junction
synapse between motor neuron and muscle cell
name a neurotransmitter that crosses a neuromuscular junction
acetylcholine
what breaks down acetylcholine
cholinesterase
meninges
prevent direct circulation of blood through the cells of the brain and spinal cord (blood brain barrier)- dura mater, arachnoid layer, pia mater.
the somatic system includes how many cranial nerves and spinal nerves
12 pairs of myelinated cranial and 31 pairs of spinal nerves.
4 types of receptors
photoreceptors- light
chemoreceptors- chemical, odour , taste
mechanoreceptor- pressure, hearing
thermoreceptor- heat and cold
what is accommodation
ability of lens to change shape
astigmatism
uneven curving of the cornea causing blurred vision
myopia
nearsightedness. Long eye ball causes image to fall in front of the retina. Need concave lens.
hyperopia
farsightedness. Short eye ball causes image to fall behind retina. Need convex lens
names of ossicles
malleus (hammer), incus (anvil), stapes (stirrup)
what structures involve balance
semicircular canals, utricle, saccule.
proprioceptors
from muscles, joints, and tendons inform the brain of the position of body parts