Your Nervous System
Peripheral Nervous System
Explain
Section 35-3
The Nervous
System
is divided into
Central nervous
system
Peripheral
nervous system
Motor
nerves
which consists of
that make up
Somatic nervous
system
Autonomic
nervous system
which is divided into
Sympathetic
nervous system
Parasympathetic
nervous system
Sensory
nerves
PNS

1.
NERVES that connect the central
nervous system to the rest of the body
Motor Division – impulses from CNS to
muscles or glands

Two Parts:


2.
Somatic Nervous System
Autonomic Nervous System
Sensory Division – transmits impulses
from sense organs to CNS
Motor Division
PNS
Somatic Nervous System

Controls voluntary movement of the
skeletal muscles
Autonomic Nervous System

Controls involuntary actions

Subdivided into two system that have
opposite effects on the same organs:
1.
Parasympathetic – decreases heart rate

2.
Controls internal organs during normal activity
Sympathetic – increases heart rate

Controls internal organs during high stress activity
Sensory Division
PNS
1. Pain Receptors
Throughout body; except brain
 Respond to chemical released by
damaged cells
 Important to recognize

Danger
 Injury
 Disease

2. Thermoreceptors
In skin, body core, hypothalamus
 Detect variations in body temperature

3. Mechanoreceptors
Skin, skeletal muscle, and inner ears
 Sensitive to

Touch
 Pressure
 Stretching of muscles
 Sound
 motion

4. Chemoreceptors

Nose and Tongue

Chemical in external environment
Figure 35-14 The Eye
Section 35-4
Vitreous humor
Muscle
Lens
Fovea
Aqueous humor
Cornea
Pupil
Optic nerve
Iris
Blood vessels
Ligaments
Retina
Choroid
Sclera
5. Photoreceptors
Eyes
 Sensitive to Light


DO NOT WRITE NEXT INFO – IT IS ON
YOUR SHEET

Cornea





Tiny muscles regulate the size
Regulates amount of light
Lens



Back of cornea
Colored part of eye
Pupil


Helps focus light
Filled with aqueous humor
Iris


Vision
Small muscles change its shape to focus on object
near and far away
Behind lens eye filled with vitreous humor
Retina



Has photoreceptors
No photoreceptors where optic nerve passes
through the back of the eye; blind spot
Two types
1.
2.
Rods – black and white
Cones – color
Pathway for Vision Reception





Light
cornea
iris and pupil
lens
Retina to photoreceptors




Rods
Cones – Fovea
Optic Nerve
Brain
Figure 35-15 The Ear
Section 35-4
Anvil Stirrup
Hammer
Oval
window
Semicircular canals
Cochlear nerve
Cochlea
Bone
Auditory canal
Tympanum
Round window
Eustachian tube
Hearing and Balance
Ear
 Two Functions

Hearing
 Detecting Positional change to movement

Hearing






Sound – air vibrations
Auditory canal – funnels air to tympanum (ear drum)
Tymapnum – vibrates
Hammer, Anvil, Stirrup- vibrate and transmit vibrations
to oval window
Cochlea – filled with fluid and vibrations create pressure
waves in the inner ear
Tiny hairs respond to waves and send messages to
brain via the cochlear nerve
Balance

Semicircular Canals
3 canals that form half circles
 Filled with fluid and hairs that detect motion of
head in relation to gravity

Figure 35-15 The Ear
Section 35-4
Anvil Stirrup
Hammer
Oval
window
Semicircular canals
Cochlear nerve
Cochlea
Bone
Auditory canal
Tympanum
Round window
Eustachian tube
Smell and Taste
Chemoreceptors pick up chemical
reception in nose and mouth
 Smell – olfactory bulb
 Taste – taste buds

Salty
 Bitter
 Sour
 Sweet

The Senses of Smell and Taste
Section 35-4
Olfactory
(smell) bulb
Taste
sensory
area
Olfactory
nerve
Thalamus
Cerebral cortex
Smell
receptor
Nasal cavity
Smell
sensory area
Taste bud
Taste
pore
Taste
receptor
Sensory
nerve fibers
Touch and Related Senses

Largest sense organ?


Sensory Receptors




SKIN
Temperature
Touch
Pain
Greatest density of touch receptors



Fingers
Toes
Face
Concept Map
Section 35-3
The Nervous
System
is divided into
Central nervous
system
Peripheral
nervous system
Motor
nerves
which consists of
that make up
Somatic nervous
system
Autonomic
nervous system
which is divided into
Sympathetic
nervous system
Parasympathetic
nervous system
Sensory
nerves