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Chapter 35
Nervous system
Unit 10:
Tissue Types:
Epithelial
Connective
Muscle
Nervous
Epithelial tissue = covers & protectsor secretes (glands)
Connective tissue = provides structure
Muscle tissue = creates movement
Nervous tissue = transmits impulses
Functioning Unit
• Neuron = nerve cell
• Star-shaped cell with numerous processes that conduct impulses
Divisions of Nervous system
• Central Nervous
System
• Includes brain
&
spinal cord
Divisions of Nervous system
• Peripheral = includes nerves leading to & from the central nervous system– Cranial nerves = brain (to or from) head &
face– Spinal nerves = spinal cord (to or from)
skin & muscles
• Autonomic nerves = spinal cord (to or from) internal organs under involuntary control
Interneuron
“wide with fright”
“heavy breathing”
heart beats faster
“butterflies” in stomach
“white as a ghost”
The Brain• Brain stem = includes medulla & pons
– Controls involuntary actions & internal organs
• Cerebellum– Controls balance & coordination (posture
& muscle tone)
• Cerebrum– Controls voluntary actions,
the senses, intelligence, emotion & memory
The Senses• Taste receptors in taste buds of tongue– Sweet, sour ,bitter,
salt
• Smell receptors in upper nasal cavity– Gaseous
stimulation
• Touch receptors in skin, etc– Touch, pressure ,
heat, cold
The Ear
• Auditory canal = vibrations pass through to…
• Tympanic membrane (eardrum)• 3 ossicles = hammer, anvil, stirrup• Cochlea = fluid-filled spiral with nerve
endings that are sensitive to vibrations• Auditory nerve = carries information to brain• Semicircular canals = for equilibrium• Eustachian tubes = (to mouth) balances
pressure
The Eye• Cornea = light containing images passes
through…
• Iris (with pupil) = colored muscle to regulate light
• Lens = behind pupil; to focus image on…
• Retina = receives image on fovea (focal point)
–Cones = sensitive to light
–Rods = functions without light
• Optic nerve = carries information to brain