The Digestive System
Digestion is the mechanical and chemical breakdown of food. The esophagus is a muscular tube through which food passes. The stomach is an organ which stores and breaks down food. The small intestine is where much of the digestion and absorption takes place. The large intestine (or colon) absorbs water. More.

The Circulatory System
The circulatory system is an organ system that permits blood and lymph circulation to transport nutrients, oxygen, carbon dioxide, hormones, blood cells, etc. to and from cells in the body to nourish it and help to fight diseases, stabilize body temperature and pH, and to maintain homeostasis. More.

The Endocrine System Organs
The endocrine system is the system of glands which secrete different types of hormones directly into the bloodstream to maintain homeostasis. The endocrine system organs: 1.Pineal gland 2.Pituitary gland 3.Thyroid gland 4.Thymus 5.Adrenal gland 6.Pancreas 7.Ovary 8.Testis More.

The Nervous System
The nervous includes the brain and the nerves as well as the senses. The nervous system can sense changes inside and outside the body through specialized cells called receptors. These responses are conveyed to the appropriate organs such as muscles or glands, at a great speed. . More Nervous Systems.

The Urinary System
The Urinary system eliminate wastes from the body. Urine is formed in the kidneys by filtration of blood. The urine is passed to the bladder where it is stored. During urination it is passed from the bladder through the urethra outside of the body. About 1-2 liters of urine are produced every day in a healthy human. More.

Integumentary System
The integumentary system protects the body from various kinds of damage such as loss of water or abrasion from the outside. It comprises the skin and its appendages including hair and nails. It serves to waterproof and cushion the deeper tissues, excrete wastes, regulate temperature and detect pain. More.

Muscular system
The muscular system of humans produces movement. There are three basic types of muscles in the body, smooth, cardiac, and skeletal. Most muscles contract as a result of conscious effort originating in the brain. Some muscles (autonomic, as in the heart) do not contract as a result of conscious effort. More

The Respiratory System
The organs of the respiratory system make oxygen enter our bodies and carbon dioxide leave. The respiratory tract has two sections: Upper Respiratory Tract and Lower. Upper tract includes Nostrils, Pharynx, Epiglottis, and the Larynx. Lower the Trachea, Bronchi, Bronchioles, and Lungs. More

Skeletal System
The skeleton provides the framework which supports the body and maintains its shape. The skeleton serves six major functions; support, movement, protection, production of blood cells, storage of ions and endocrine regulation. The human skeleton is composed of 270 bones at birth and by the time adulthood is reached some bones have fused together to give a total of 206 bones in the body. More

Female Reproductive System
The human female reproductive system (or female genital system) contains two main parts: the uterus, which hosts the developing fetus, produces vaginal and uterine secretions, and passes the male's sperm through to the fallopian tubes; and the ovaries, which produce the female's egg cells. More.

Male Reproductive System
The human male reproductive system is a series of organs located outside of the body and around the pelvic region that contribute towards the reproductive process. The primary direct function of the male reproductive system is to provide the male [gamete] or [spermatozoa] for fertilization of the ovum. More.