The Nervous System

Organization of the Animal Nervous System (Fig. 34.1)

3 kinds of neurons (Fig. 34.2)

 

peripheral nervous system

sensory neurons

motor neurons

central nervous system (CNS)

association neurons (interneurons)

Invertebrate Nervous Systems (Fig. 34.3)

nerve net and no brain.

nerves and ganglia or brains.

vertebrates

more complex sensory mechanisms

differentiation into central and peripheral nervous systems (Fig. 34.16)

differentiation of sensory and motor neurons

elaboration of the brain. (Image)

Neurons (Fig. 34.4)

dendrites

cell body

axon

neuroglia

Schwann cell

 

myelin sheath.

 

multiple sclerosis

normal neuron, affected neuron, affected CNS,  muscle atrophy, diagnosis MRI and lumbar puncture

The Synapse (Fig. 34.7)

presynaptic neuron

 

postsynaptic neuron.

neurotransmitter

specific receptors

Kinds of Synapses

excitatory

action potential

inhibitory

inhibits the impulse

integration (
Fig. 34.8)

Neuromodulators and Drug Addiction

Neuromodulators

prolonging or inhibiting it

mood and emotion (Fig. 34.9)

Drug Addiction

physiological dependence (
Fig. 34.10)


Is Addiction to Smoking Cigarettes Drug Addiction?

nicotine

Divisions of the vertebrate nervous system (Fig. 34.20)

The Central Nervous System

     How the Brain Works (
Fig. 34.11 and 34.12)

cerebrum

cerebral hemispheres.

thin cerebral cortex

myelinated nerve fibers

tracts

stroke
(Movie)

    The Thalamus and Hypothalamus Process Information

thalamus: sensory information

hypothalamus: internal functions

limbic system (
Fig. 34.13)

    The Cerebellum Coordinates Muscle Movements

muscular coordination, balance, and posture

    The Brain Stem Controls Vital Body Processes

medulla oblongata controls breathing rate, heartbeat, and blood vessel diameter.

reticular formation: sleep and waking

Language and Other Higher Functions (Fig. 34.14)

The left hemisphere is the dominant one for language in 90% of right-handed people and two-thirds of left-handers.

The dominant hemisphere is adept at sequential reasoning while the nondominant hemisphere is adept at spatial reasoning.

Short-term memories are transient and are stored electrically.

Long-term memories involve structural changes within certain neural connections in the brain.

 

Alzheimer disease: aged brain

The Spinal Cord (Fig. 34.15)

Spinal cord regeneration

fibroblast growth factor

The Peripheral Nervous System

Voluntary nervous system and the autonomic nervous system.

Voluntary Nervous System

skeletal muscles.

reflexes. (
Fig. 34.18)

Autonomic Nervous System: smooth muscles and glands: no conscious control. (Fig. 34.19)

sympathetic nervous system

 

ganglia

parasympathetic nervous system

internal organs and smooth muscles

 

homeostasis

The Sensory Nervous System

Sensory Receptors (Fig. 34.20)

sensory organs.

Path of sensory information

Stimulation

Transduction

Transmission

Sensing the Internal Environment

changes in blood chemistry, pain and tissue damage, muscle contraction and posture (Fig. 34.21), blood pressure (Fig. 34.22), and touch below the skin's surface.

Sensing Gravity: Balance (Fig. 34.23)

Balance (Fig. 34.23b)

   Utricle: horizontal changes

   Saccule: vertical changes

   Otoliths

   Hair cells

   inner ear.

Motion

   semicircular canals (Fig. 34.23a)

   cilia

   cupula (Fig 34.23c)

   hair cells

Sensing Chemicals: Taste and Smell

Taste

   Tongue with papillae containing taste buds

   sour, sweet, bitter, salty, and umami (meaty) (Fig. 34.24)

Smell

   nasal passages (Fig. 34.25) Olfactory area, receptor cells

Sensing Sounds: Hearing (Fig. 34.26) (Movie)

air pressure waves

 

eardrum

 

middle ear

 

hammer, anvil, stirrup.

cochlea of the inner ear.

hair cells

membrane

different pitches

volume

 

Problems - earwax, earwax plug, Q tips, perforated eardrum, middle ear infection, head phones, permanent hearing loss.

 

Lateral line system (Fig. 34.27)

 

Sonar and echolocation (Fig. 34.28)

Sensing Light: Vision (the perception of light)

Eye structure in other animals (Fig. 34.30) and (Fig. 34.29)

 

Structure of the vertebrate eye (Fig. 34.31)

cornea

lens

 

ciliary muscles

pupil

 

iris

retina (Fig. 34.36)

 

rods and cones (Fig. 34.32)

 

color vision (Fig. 34.34)

fovea

 

special pigments

Binocular vision  (
Fig. 34.37)

 

Vision problems - Snellen chart - chart for children or non-readers
20/20
- normal - can read at 20 feet the letters which could be read by a person with "normal" vision.
20/10 - better than normal vision - can read letters at 20 feet that would be read by a person with "normal" vision at 10 feet
20/50 - worse than normal vision - can read letters at 20 feet that would be read by a person with "normal" vision at 50 feet

Nearsightedness or myopia

 

Farsightedness or hyperopia

 

Correction with glasses


Lasik surgery results

 

Presbyopia looks like this


Astigmatism

 

Cataracts   view    surgery

 

Color blindness