Levels of Organization

A group of specialized cells build tissue

A group of  tissues build an organ

A group of organs build an organ system

A group of organ systems build an organism

*Least Complex → Most Complex

*Cells → Tissues → Organs → Organ System → Organism

Tissues

Tissue - group of similar cells that perform the same function

*example: nervous, epithelial, muscle, connective

N.E.M.C

Organs

Organ - structure that is made up of different kinds of tissue.

Examples: heart, brain, lungs, and skin

H.B.L.S

Organ Systems

Organ Systems - a group of organs that work together, carrying out major functions.

Example: Muscular System, Nervous Systems

Organism

Organism - a living thing

In multicellular organisms; all the organ systems working together.

How do you move?

*The nervous system tells your muscles when and how to act.

*When muscles are told to move they pull on the bones of the skeletal system to allow for the movement.

Transporting materials

*Circulatory system brings materials such as oxygen to all cells and takes away waste from those cells such as carbon dioxide.

(circulatory system - circulates materials)

Breathing in, Breathing out

*Respiratory system moves oxygen into the body and carbon dioxide out of the body.

(When thinking about the respiratory system think about when we breathe in and out)

*When oxygen moves into the bloodstream the circulatory system delivers it to all cells and carries back carbon dioxide to be expelled.

Getting Food

*The oxygen brought in by the respiratory and circulatory systems is used to release energy from sugar in your food.

*Digestive System breaks down food into nutrients.

Absorption - process by which nutrients move from the digestive system into the bloodstream, to be delivered to all cells by the circulatory system.

Moving Waste

*Excretory system eliminates wastes from your body.

Controlling Body Functions

Your nervous system reacts to what is going on in your environment through your senses and tells your body how to react.

Stimulus - a signal in the environment that makes you react.

Response - what your body does in reaction to a stimulus.

The Nervous System

Central Nervous System

Brain and spinal cord

Messages are received, processed, and a response is sent out

Peripheral Nervous System

Nerves

voluntary actions:

• walking

involuntary actions

• breathing

Using our Senses

Chemical Input - a chemical that enters the body

Ex: smelling or tasting something

Mechanical Input - signals that enter the body through physical touch or vibration

Ex: touching or hearing something

Electromagnetic Input - signals that enter the body in the form of electromagnetic stimuli

Ex: seeing something

Picking Up Signals

Nerve Cell - a specialized cell for transmitting fast electro-chemical signals. Also called a neuron.

Sensory Receptors - a nerve ending that sends signals to the central nervous system when it is stimulated.

Processing Signals

Brain - organ that serves as the primary control center of the nervous system

Stimulus - an action or condition that provokes a response

Behavior - what a plant or animal does