What is a cell?

Cells

-Definition of cell:a is the smallest part of any living thing.

-Parts of the cells:

Cell Membrane - forms the outer boundary of the cell and allows only certain materials to move into or out of the cell
Cytoplasm - a gel-like material inside the cell; it contains water and nutrients for the cell
Nucleus - directs the activity of a cell; it contains chromosomes with the DNA
Nuclear Membrane - separates the nucleus from the cytoplasm
Endoplasmic Reticulum - moves materials around in the cell
Ribosomes - make protein for the cell
Golgi Bodies - are used for packaging and secreting of energy
Mitochondria - break down food and release energy to the cell
Lysosomes - are chemicals used to digest waste
Vacuoles - are storage areas for the cell
Some organelles are found only in Plant cells. These organelles are
Cell Wall - provides structure to the plant cell
Chloroplasts - contain chlorophyll that is make food for the plant cell

Tissues

Tissue in animals

Epitherial tissue- Tissues composed of layers of cells that cover organ surfaces such as surface of the skin and inner lining of digestive tract: the tissues that serve for protection, secretion, and absorption

Connective tissue-As the name suggests, connective tissue holds everything together. Connective tissue is characterized by the separation of the cells by an inorganic material, which is called extracellular matrix. Bone and blood are connective tissues

Muscle tissue-Muscle cells contain contractile filaments that move past each other and change the size of the cell. Muscle tissue also is separated into three distinct categories: visceral or smooth muscle, which is found in the inner linings of organs; skeletal muscle, which is found attached to bone in order for mobility to take place; and cardiac muscle which is found in the heart

Nervous- Cells forming the brain, spinal cord and peripheral nervous system.

Circulatory System

The circulatory system is formed by:
-Heart
-Blod vessels (arteries,veins,capillaries)

This is a photo of a circulatory system.

What the human body is made of

Our body is made up of apparatus and systems.
Each apparatus or system is made up of several organs.

Each organ, in turn, is made up of tissues. And the tissues are formed by cells.This photo shows blood red cells in one of the veins of the liver.