Control & Coordination

CONTROL AND COORDINATION

The Nervous SystemNeuronsCentral Nervous System

•Brain•Spinal Cord

Peripheral Nervous SystemThe Senses

Organization in the Body

Several organs working together; each system has one major role

A distinct body part that carries out one or more main functions

A group of similar cells that carry out a specialized job

The basic building block of all living things, plant or animal

Specialized structures inside a cell that have specific functions

A collection of systemsOO

ORGANELLE

CELL

TISSUE

SYSTEM

BODY

ORGAN

The Nervous

System

Helps the body adjust to changes in your environment

FUNCTIONSStimulus

Any change inside or outside your body that brings about a response

HomeostasisRegulation of steady conditions inside the body

Neurons

Building blocks of the nervous system 

100 billion neurons in your brain alone30,000 on a pinheadThey communicate with each other

thousands of times a second.Bundles of neurons make up nerves

The Nervous System

Central Nervous System =Brain + Spinal Cord

Peripheral Nervous System =Nerves to rest of body

3 Types of Nerve Cells

Sensory NeuronsReceive information form a sensory receptor and send impulses to the CNS

InterneuronsRelay impulses from sensory neurons to motor neurons

Motor NeuronsCarry impulse from the CNS to muscles and glands through out the body

Parts of a Neuron

 3 MAIN PARTSDendrites - receive

messages from other neurons

Cell Body – nucleus is found here

Axon - sends messages to other neurons

Parts of a Neuron

Dendrites

Cell Body

Axon

Synapse

Space between each neuronNeurotransmitters are the messengers that

travel across each synapseThey are chemical signals that neurons use to

talk to each other, which is what makes your brain work. They help determine how you feel, think and act.

NeurotransmittersSerotonin - involved in mood (such as helping you

to feel happy), sleep, mental health, blood pressure and heartbeat.

Dopamine - important in helping to regulate physical movement, pleasure, and thought.Missing in patients with Parkinson's Disease.

Neurotransmitters

• Acetylcholine - involved in regulating muscles, memory, mood, sleep, and organs (like the heart).– Lowered amounts associated with

Alzheimer’s Disease

Central Nervous System(C.N.S.)

BRAIN

SPINALCORD

Cerebrum Largest part of the brain Interprets impulses from

the senses

Responsible for: thinking and learningcreativity five sensesmemory and emotionproblem-solvingdecisions

Cerebellum

Coordinates voluntary muscle movement

Helps maintain balance

When a ball is thrown to you, the cerebellum coordinates the proper response to prevent injury

Brainstem Controls involuntary

actions Connects the brain to the

spinal cord Regulates heart rate,

breathing, swallowing, blinking, and more 

Made up of:the midbrainPonsmedulla

Spinal CordMade up of bundles of

neuronsCarries impulses to and

from the brainTogether, the brain and

spinal cord make up the Central Nervous System (C.N.S.)

Fun fact:The spinal cord is about

45 cm long in men and 43 cm long in women.

Peripheral Nervous System(P.N.S.)

Connects the C.N.S. with the rest of the body

• sensory nerves take impulse from stimulus (sensory receptors) to the CNS

• motor nerves take impulse from the CNS to the muscles and glands that take action.

ReflexREFLEX

An involuntary, automatic response to a stimulus controlled by the spinal cord

Like when the doctor uses the rubber mallet on your tendon below your knee

Movement when someone unexpectedly throws something at you

Reflex ArcWhen the body receives a painful stimulus (stepping

on a nail, touching a hot surface, etc), the body responds super-fast.

Path of reflex arc:

STIMULUS sensory receptor sensory nerve spinal cord (interneuron) motor nerve muscle RESPONSEAn impulse continues up to the brain to be interpreted by the cerebrum, BUT, meanwhile the affected area has already produced a response!

Senses

VisionSensory Receptors

Rods sense brightnessCones sense color

The retina, in the back of your eye, has cells that are sensitive to light. They connect directly to your

brain.

Senses

Hearing Sound waves make your

eardrum vibrate. Small bones in your ear

vibrate (hammer, anvil, stirrup)

Vibrations go through the snail-like cochlea, which turns them into nerve impulses to your brain.

SensesTaste10,000 taste buds in your

mouthYour tongue picks up four

types of taste:• sweet• sour• bitter• salty

Sweet and salty are least sensitive

Bitter ones are most sensitive

Senses

SmellOdor particles drift into your noseStimulate sensory receptors –

olfactory cells – in nasal passagesSensory receptors send impulses

to your brain to be interpreted.

Senses

There are at least six types of touch receptors

in your skin:• Hot• Cold• Pain

• Pressure• Touch

• Fine touch

TOUCH