Please enable JavaScript.
Coggle requires JavaScript to display documents.
Nervous System (Senses (Types of Receptors (based on stimulus type)…
Nervous System
Senses
Types of Receptors (based on stimulus origin)
Exteroceptors
stimulus origin is our environment
where? skin and special senses (sight, hearing, taste, olfaction, equilibrium)
Interoceptors
stimulus origin is internal organs
Proprioceptors
stimulus origin are our muscles, tendons, ligaments, and joints
proprio meaning "own" or SELF
Types of Receptors (based on stimulus type)
Thermoreceptor: temperature - cold and warm receptors - skin and internal
Photoreceptor: light -eye
Chemoreceptor: chemical - nose (air molecules), tongue, blood
Nociceptor: PAIN. where? all over. skin, muscles, joints, bones, and internal organs!
Mechanoreceptor:
mechanoreceptors that detect stretch are located in the aorta and carotid arteries - also classify as proprioceptors
touch, pressure vibration, stretch
Baroreceptor: sensitive to blood PRESSURE
MEMORY TRICK: The Peacock Creates No More Biscuits
Eye Components and Visual Pathway
3 tunics
Fibrous layer
A. sclera
purpose: protective, gives shape
white, D.C.T., anchor for extrinsic muscles
B. cornea - TRANSPARENT, allows light in, focuses light
Vascular layer
choroid - continuous with ciliary body muscle (that changes the shape of the lens)
nourishes other layers
pigment absorbs light
prevents scattering
depicted as pink in image, however anatomically black
Inner layer - retina
very thin, but very important because it has photoreceptors
axons from photoreceptors coverge to form optic nerve
yellow layer in notes
Pathway:
light
cornea
lens
retina (photoreceptors)
optic nerve (cranial nerve II)
optic chiasma
1 more item...
Olfaction Components and Pathway
location: roof of nasal cavity
epithelium: pseudostratified columnar with what present? olfactory sensory neurons
Pathway:
olfactory sensory neurons
olfactory bulb
olfactory tract
limbic region (emotional part of the brain, memory as well)
primary olfactory cortex in temporal lobe
Gustation Components and Pathway
location: tongue, inner cheeks, pharynx (throat), palate, epiglottis
50-100 epithelial cells take in chemicals
<--- Pathway
taste buds w/ receptor cells
3 cranial nerves
medulla oblongata
thalamus
primary gustory cortex in the insula
THREE CRANIAL NERVES that transmit info f/ tongue to brain
Facial (C.N. VII)
Glossopharyngeal (C.N. IX)
Vagus (C.N. X)
Ear Components and Pathway
External (outer) ear
auricle (pinna) - gather and funnel sound waves, and amplify
Middle ear
tympanic membrane - ear drum - vibrates and transmits vibrations
auditory ossicles - transmits vibrations
<-- Pathway
sound - vibrations
auricle gathers sound waves
funneled into middle ear
tympanic membrane vibrates and transmits vibrations
middle ear
auditory ossicles
1 more item...
Nervous System Organization
Central Nervous System (CNS)
main structures
brain and spinal cord
functions
receive, process, and respond to sensory input
Peripheral Nervous System (PNS)
functions
gathers sensory info f/ receptors and passes it on to cranial and spinal nerves
main structures
cranial nerves, spinal nerves, ganglia - cluster/group of neuron cell bodies
somatic motor division
sending messages to mainly to skin, body wall (torso/trunk), skeletal muscles
autonomic motor division
sending messages to mainly ventral body cavity contents: smooth muscle, glands, arrector pili muscle, cardiac muscle, sweat glands, smooth muscle of blood vessels (aka things you don't have to think about
Anatomy of Nervous System
Nerve Components
nerve is like a bundle of wires
myelin sheath - axon insulation coating - only SOME axons
endoneurium - loose connective tissue
perineurium - fibrous connective tissue
epineurium - tough, fibrous C.T.; surrounds all fascicles
bundle of axons is called a fascicle
Glial Cells
CNS
Astrocytes
most abundant
-its processes contact axons and capillaries
supportive
helps maintain a proper chemical environment
Microglia
phagocyte - eats!!
destroys invading microbes and damaged/dying nervous tissue
Ependymal cells
simple cuboidal/columnar epithelium
apical and ciliated - why cilia? help circulate cerebrospinal fluid
location: ventricles (space in brain, filled with CSF)
microvilli
oligodendrocytes
see myelination below
PNS
Schwann cells
see myelination below
Satellite cells
surrounding ganglia
remind me of sting rays :smiley:
function: supportive, help regulate what goes in/out of neuron cell bodies
FYI ganglion = cluster of neural cell bodies
Myelination
covering of MOSTLY LIPID, and some protein, around some axons
Purpose? insulator! makes signals travel more quickly!
myelin sheath gaps called Nodes of Ranvier
CNS
oligodendrocytes
can wrap around multiple axons
function: creation of myelin sheath
PNS
Schwann cells
wraps one piece around one axon, but wraps "like 100 times"
Schwann cells considered nonmyelinated
can wrap around a bundle
think fruit roll-up
Neurons
Major Components of a Neuron
cell body
contains the nucleus
nucleus and nucleolus
nucleolus creates ribosomes
chromatophilic substance
dense region of rough E.R. and free ribosomes - creates plasma membrane & other proteins (taking place outside of the nucleus)
dendrites
input of the neuron
axon hillock
where axon leaves cell body
axon
output of the neuron
axon terminals
end of axons
axon collateral
branch of axon from main axon
Functional Types of Neurons
motor or efferent
sending AWAY, multipolar, most abundant
sensory or afferent
sending TO, unipolar
interneurons or association
CNS only - btwn neurons, multipolar
Structural Types of Neurons
multipolar
one long axon, lots of branching dendrites
bipolar
special sensory, examples: eye and nose
unipolar
single axon that heads in different directions