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