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Nervous system (senses (eye component and visual pathway (other components…
Nervous system
senses
types of receptors
based on origin
exteroceptors
origin is outer environment
skin special senses
interoceptors
internal organs
poprioceptors
origin is muscle and their tendons ligaments and joints
based on type
thermoreceptors
sensitive to temp / location=skin
photoreceptor
sensitive to light / location=eye
chemoreceptor
sensitive to chemicals / location=nose,tongue
nociceptor
sensitive to pain
mechanoreceptor
sensitive to touch, pressure, vibration, stretch
baroreceptor
sensitive to blood pressure / location= blood vessels, arteries
eye component and visual pathway
fibrous layer
sclera
white part of eye / Dense connective tissue
move eyeball around, gives shape, protective
cornea
transparent
allows light into eye, focuses light
vascular layer
choroid
nourishes other layers, pigment absorbs light and prevents scattering
continuous with ciliary body muscle
inner layer
retina
axons from photoreceptors- converge to form optic nerve
rods
most abundant - sensitive to light & dark
cones
give us color vision - work best in bright light
visual pathway=
cornea > lens > retina > optic nerve > optic chiasma > optic tract > midbrain > thalamus > primary visual cortex
other components
lens - focuses light on retina , Location= posterior to iris
iris - colored part of eye, for dilation or constriction of pupil
optic disc - blind spot
macula lutea - part of retina, clearest vision
fovea centrais -in ML, spot that gives clearest vision
olfaction component and pathway
roof of nasal cavity- cribriform foramina, olfactory bulb
pathway= nerves > bulbs > tract (primary olfaction cortex) > limbic region
gustation components and pathway
taste buds location - tongue, inner cheek, pharynx (throat), palate, epiglottis
pathway
taste buds w/ receptor cells > 3 cranial nerves** > medullary oblongata, thalamus, primary gustation cortex
**3 cranial nerves
facial nerve (VII) - Glossopharyngeal (IX) - vagus (X)
Ear components and pathway
outer ear
auricle-pinna : gather, funnel sound waves
middle ear
tympanic- vibrates, transmits vibrations
auditory ossicles- transmits vibrations to cochlea
pathway- Cochlear nerve > medulla oblongata > pons > midbrain > thalamus >primary aduitory cortex
nervous system organization
Central nervous system (CNS)
structures- brain and spinal cord
functions- receive, process, and responds to sensory input
Peripheral nervous system (PNS)
structures- cranial nerves, spinal nerves, ganglia
functions- gathers sensory info from all receptors and passes it on to CNS
somatic division
skin, body wall, skeletal muscles (everything except ventral body cavity content.
hearing equilibrium, vision
autonomic division
ventral body cavity content - smooth muscle, cardiac muscle, glands
taste, olfaction
neurons
major components
cell body, nucleus, nucleolus, chromatophilic substance, dendrites, axon hillock, axon, axon collaterals, terminal arborization, terminal boutons (terminals)
structural types
unipolar
1 process coming off of cell body
multipolar
see most often, many processes coming off of cell body
bipolar
two processes coming off of cell body
functional types
interneurons
CNS only, between neurons, shorter, multipolar
motor/efferent neurons
signals travel away from CNS, multipolar
sensory/afferent neurons
sends signals to CNS- unipolar
anatomy of nervous system
nerve components
axon, myelin sheath, endoneurium, fascicle, perineurium, epineurium
glial cells
astrocytes
support neurons, maintain proper chemical environment ,most abundant, Located in CNS
microglia
Phagocytes, destroys invading microbes, Located in CNS
ependymal cells
in ventricles(filled with cerebrospinal fluid), cells help create the fluid, travels back into body, located in CNS
PNS- satellite cells
surround cell body in ganglia, supportive to cell bodies& regulate what goes in and out of cell bodies
oligodendrocytes
Cretes myelin sheath
Schwann cells
creates myelin sheath in PNS