I control everything…

Functions of the Nervous System

1. Communication and coordination Adapt and respond to changes from both inside and

outside the body

2. Site of reasoning- your brain

3. Two main divisions Central nervous system (CNS): brain and spinal cord Peripheral nervous system- the nerves

Neuron- basic structural unit of the nervous system

Dendrites- carry impulses towards the cell

Axon-carry impulses away from the cell

Myelin sheath Synaptic terminal

Epinephrine Norepinephrine Acetylcholine

Nerves

Nerves are made of many nerve cells

Afferent-sensory nerves carry message to brain

Efferent-motor neurons carry message from brain to muscle

Associate- do both

Heads up

The Nervous System

Major division - Central vs. Peripheral

Central or CNS- brain and spinal cord

Peripheral- nerves connecting CNS to muscles and organs

Central Nervous System

Peripheral Nervous System

Central Nervous System

Brain and Spinal Cord

SpinalCord

Brain

Cerebrum Cerebrum-largest

part of brain. Responsible for reasoning, thought, memory, speech, sensation, etc.

Divided into two halves.

Further divided into lobes; occipital, parietal, temporal and frontal

Parts of the Brain

Cerebellum and Brain Stem Cerebellum-

responsible for muscle coordination

Brain stem- most basic functions; respiration, swallowing, blood pressure. Lower part (medulla oblongata) is continuous with spinal cord

Parts of the brain and their functions

Spinal cord

Spinal cord- begins at foramen magnum and ends at second lumbar vertebrae

Contains both afferent (to the brain) and efferent (motor neurons- away from the brain)

Both the brain and spinal cord are covered by a membrane system called the meninges

In addition, the brain has four hollow areas called ventricles. Cerebrospinal fluid is produced in the ventricles and bathes the brain and spinal column

Left & Right sides are separate

Corpus Callosum : major pathway between hemispheres

Some functions are ‘lateralized’ language on left math, music on right

Lateralization is never 100%

Brain has 2 Hemispheres

LeftHemisphere

Corpus CallosumRight

Hemisphere

Each hemisphere is divided into 4 lobes

Frontal

Parietal

Occipital

Temporal

Sensory Information sent to opposite hemisphere

Principle is Contralateral Organization

Sensory data crosses over in pathways leading to the cortex

Visual Crossover left visual field to right

hemisphere right field to left

Other senses similar

Left visualfield

Right visualfield

Opticnerves

CorpusCallosum

Left VisualCortex

Right VisualCortex

Contralateral Motor Control

Movements controled by motor area

Right hemisphere controls left side of body

Left hemisphere controls right side

Motor nerves cross sides in spinal cord

Somatosensory CortexMotor Cortex

Corpus Callosum

Major ( but not only) pathway between sides

Connects comparable structures on each side

Permits data received on one side to be processed in both hemispheres

Aids motor coordination of left and right side

Corpus Callosum

Medial surface of right hemisphere

Corpus Callosum

What happens when the corpus callosum is cut?

Sensory inputs are still crossedMotor outputs are still crossedHemispheres can’t exchange data

Nonverbalrighthemisphere

Verballefthemisphere

??

“What didyou see?”

Picture to left brain can name the object left hand cannot

identify by touch

Picture to right brain can’t name the object

left hand can identify by touch

“Using your left hand,Pick up what you saw.”

The ‘Split Brain’ studies

I saw anapple.

“What didyou see?”

Nonverbalrighthemisphere

Verballefthemisphere

Localization of function

Frontal

Parietal

Occipital

Temporal

Peripheral Nervous System

3 kinds of neurons connect CNS to the body sensory motor interneurons

Motor - CNS to muscles and organs

Sensory - sensory receptors to CNS

Interneurons: Connections Within CNS

SpinalCord

Brain

Nerves

Peripheral Nervous System

Skeletal(Somatic)

Sympathetic Parasympathetic

Autonomic

Peripheral Nervous System

Somatic System

Nerves to/from spinal cord control muscle

movements somatosensory

inputs Both Voluntary and

reflex movements Skeletal Reflexes

simplest is spinal reflex arc

Muscle

MotorNeuron

Interneuron

Skin receptors

SensoryNeuron

Brain

Autonomic System

Two divisions: sympathetic Parasympatheitic

Control involuntary functions heartbeat blood pressure respiration perspiration digestion

Can be influenced by thought and emotion

Sympathetic

“ Fight or flight” response Release adrenaline and

noradrenaline Increases heart rate and

blood pressure Increases blood flow to

skeletal muscles Inhibits digestive functions

CENTRAL NERVOUS SYSTEMBrain

Spinalcord

SYMPATHETIC

Dilates pupil

Stimulates salivation

Relaxes bronchi

Accelerates heartbeat

Inhibits activity

Stimulates glucose

Secretion of adrenaline,nonadrenaline

Relaxes bladder

Stimulates ejaculationin male

Sympatheticganglia

Salivaryglands

Lungs

Heart

Stomach

Pancreas

Liver

Adrenalgland

Kidney

Parasympathetic

“ Rest and digest ” system

Calms body to conserve and maintain energy

Lowers heartbeat, breathing rate, blood pressure

CENTRAL NERVOUS SYSTEMBrain

PARASYMPATHETIC

Spinalcord

Stimulates salivation

Constricts bronchi

Slows heartbeat

Stimulates activity

Contracts bladder

Stimulates erectionof sex organs

Stimulates gallbladder

Gallbladder

Contracts pupil

Summary of autonomic differences

Autonomic nervous system controls physiological arousal

Sympatheticdivision (arousing)

Parasympatheticdivision (calming)

Pupils dilate EYES Pupils contract

Decreases SALVATION Increases

Perspires SKIN Dries

Increases RESPERATION Decreases

Accelerates HEART Slows

Inhibits DIGESTION Activates

Secrete stresshormones

ADRENALGLANDS

Decrease secretionof stress hormones

Disorders of the nervous system

Meningitis- inflammation of the linings of the brain and spinal cord

Encephalitis- inflammation of the brain Epilepsy-seizure disorder. Excessive discharge

from neurons. 1 in 200 suffer. Grand mal or petit mal seizures

Cerebral palsy- disturbance in voluntary muscular action

Parkinson’s –decreased neurotransmitter MS multiple sclerosis- autoimmune

The Nervous System: Summary

Major structures of the nervous CNS, Somatic, Autonomic Two hemispheres & 4 lobes

Organization contralateral input & output primary sensory areas motor areas Commissure

Localization of functions

Central Nervous System

Peripheral Nervous System

Sense organs carry messages about the environment to the

central nervous system.

The eyes, ears, nose, tongue, and skin are examples of sense organs.

The sense organs gather information (light, sound, heat, and pressure) from the environment.

The environment is everything outside the body.

The sense organs gather information from outside the body, then send the messages to the brain.

Vision is your ability to see.

Vision involves the eye and the brain.

The eye is one of your sense organs.

The eye is made of the iris and the pupil.

The eye gathers pictures and sends them to the brain.

The colored part of the eye is the iris.

The black part of the eye is the pupil.

The pupil becomes larger and smaller as it controls the light

coming into the eye.

IrisPupil

When a sound is made, the air around the sound vibrates.

Hearing starts when some of the sound waves go into the ear.

There are nine main parts of the ear.

1. Pinna

2. Ear canal

3. Ear drum

5. Anvil

6. Stirrup

7. Cochlea

4. Hammer 8. Eustachian tube

9. Auditory nerve

The ear canal is the tube between the outside of the ear and the ear drum.

The ear drum is in the middle ear. It vibrates when sound waves hit it.

The pinna is the part of the ear that you can see.

The three smallest bones in the body, the hammer, the anvil, and the stirrup, are in the middle ear.

The hammer gets the vibrations from the eardrum, then sends them to the anvil.

The anvil passes the vibrations to the stirrup.

The stirrup passes the vibrations to the inner ear.

The inner ear is made of the cochlea and liquid.

The cochlea is in the inner ear. The cochlea looks like a shell.

The Eustachian tube controls the amount of pressure in the ear.

The auditory nerve carries the hearing information to the brain and the brain tells

us what we heard.

The ear works with the brain to control your balance.

All of your movements are controlled by balance and muscles.

The liquid in your inner ear is responsible for your balance.

The liquid in your ear moves when we move. The liquid movement sends information to the

brain to tell it how we are moving.

The sense of touch is located in the skin.

The nerves in the skin allow us to feel texture, pressure, heat, cold, and pain.

Texture is how something feels.

The nose controls your sense of smell.

The nose is able to smell 80 different kinds of smells.

Your sense of taste comes from the taste buds in the tongue.

Taste buds are the parts on the tongue that allow us to taste.

The four kinds of taste buds are sweet, sour, bitter, and salty.

Tastes and smells work together to make flavors.

Flavors are the tastes of food and drinks.