Transcript Chapter 11 - Nervous System

Spinal cord and Peripheral
nervous system
Spinal cord - Functions
 Sensory
and motor pathway
Reflex arc (spinal cord)
 Reflex
center –
 Sensory
receptor
 Sensory neuron
 Interneuron (association neuron)
 Motor neuron (effector)
 An effector organ
Spinal Cord Anatomy
 Association
neuron
 Motor
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Matter – “butterfly” interneurons
 White Matter – myelinated
 Gray
Spinal cord Anatomy
Spinal Cord tracts
 Sensory
 1.
Dorsal column
2. Spinothalamic
 Ascending tracts
 temperature,
pressure, pain, light, touch
Spinal cord tracts continued
Motor tracts
1. Corticospinal
 Decending
 Skeletal
tone, voluntary muscle movement
Nerves attached to Sp. Cord

Dorsal Root Ganglia
– bundle of sensory
nerves
 Ventral Root
Ganglia – bundle of
motor fibers
Peripheral Nervous system
Peripheral Nervous System
PNS
Somatic
Autonomic Nervous
systyem
sympathtic Nervous
system
parasympathetic nervous
system
Somatic Nervous System
 Includes
all nerves in the
musculoskeletal system, sense organs
 Receptor (receives impulse) to Effector
(muscle fiber)
Autonomic Nervous System
 Motor
neurons that control internal
organs (involuntary)
 Innervate
all organs
 Two divisions of
Autonomic Nervous System

Sympathetic
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“Fight or flight
response”
Inhibits digestion
Pupils dilate
Accelerates heart
rate
Increase breathing
rate.

Parasympathetic

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Normal state
Promotes digestion
Pupils constrict
Normal heartbeat
“feed and breed”
The Eye: Photoreceptor
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Lens – refraction and
focusing
Iris – controls entrance
of light into eye
Pupil – window into the
eye
Choroid – blood
vessels, absorbs stray
light
Eye anatomy continued
Sclera – white
fiborous layer,
protection
 Humors –
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
Aqueous humor –
between the cornea
an lens
Viterous humor – fills
large cavity,
gelatinous material
Eye Anatomy continued
Ciliary body – holds
lens in place
 Retina – contains
receptors
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Cones – color vision
Rods – black and
white vision
Optic Nerve
Rods and Cones Illustration
Eye Anatomy Continued
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Optic Nerve – picks up
impulse
Ciliary muscles –
controls the shape of
the lens
Accommodation –


Additional focusing
power
Near object – ciliary
muscle contracts, lens
becomes round
Physiology of sight

Focusing – light rays
bent by cornea,
focus on the retina,
refraction and
inverted
Fields of Vision Illustration
Refer to Lab on eye dissection
Cross section of head
Normal Vision 20/20
 at
a distance of 20 feet, you can read a
certain line (labeled 20) on the chart
and that your vision is normal.
 20/40 -
Nearsightedness (myopic)
Farsightedness (hyperopia)
Disorders of the Eye:
Glaucoma – built up pressure in the eye due
to lack of aqueous humor drainage
Vision of a person with Glaucoma
Cataracts- clouding of the lens