Human Anatomy: Human Body Systems
About The Human Body
The human body is defined as the entire structure of a human being
and comprises a head, neck, trunk (which includes the thorax and abdomen), arms
and hands, legs and feet. Every part of the body is composed of various types
of cells, the fundamental unit of life. The study of the human body involves
anatomy and physiology. Human anatomy is primarily the scientific study of the
morphology of the human body. Human physiology is the science of the
mechanical, physical, bio-electrical, and biochemical functions of humans in
good health, their organs, and the cells of which they are composed.
Systems of the Human Body
The human body consists of many interacting systems. Each system
contributes to the maintenance of homeostasis, of itself, other systems, and
the entire body. A system consists of two or more organs, which are functional
collections of tissue.
Systems
do not work in isolation, and the well-being of the person depends upon the
well-being of all the interacting body systems. Some combining systems are
referred to by their joint names such as the nervous system and the endocrine
system known together as the neuroendocrine system.
The Immune System
The immune system consists of the white blood cells, the thymus,
lymph nodes and lymph channels, which are also part of the lymphatic system.
The immune system provides a mechanism for the body to distinguish its own
cells and tissues from alien cells and substances and to neutralize or destroy the
latter by using specialized proteins such as antibodies, cytokines, and
toll-like receptors, among many others.
The Urinary System
The urinary system consists of the kidneys, ureters, bladder, and
urethra. The urinary system removes water from the blood to produce urine,
which carries a variety of waste molecules and excess ions and water out of the
body.
The Musculoskeletal System
The musculoskeletal system consists of the human skeleton (which
includes bones, ligaments, tendons, and cartilage) and attached muscles. It
gives the body basic structure and the ability for movement. In addition to
their structural role, the larger bones in the body contain bone marrow, the
site of production of blood cells. Also, all bones are major storage sites for
calcium and phosphate. This system can be split up into the muscular system and
the skeletal system.
The Circulatory System
The human circulatory system or cardiovascular system comprises
the heart and blood vessels (arteries, veins, and capillaries). The heart propels
the circulation of the blood, which serves as a “transportation system” to
transfer oxygen, fuel, nutrients, waste products, immune cells, and signaling
molecules (i.e., hormones) from one part of the body to another. The blood
consists of fluid that carries cells in the circulation, including some that
move from tissue to blood vessels and back, as well as the spleen and bone
marrow.
The Endocrine System
The endocrine system consists of the principal endocrine glands:
the pituitary, thyroid, adrenals, pancreas, parathyroids, and gonads, but
nearly all organs and tissues produce specific endocrine hormones as well. The
endocrine hormones serve as signals from one body system to another regarding
an enormous array of conditions, and resulting in variety of changes of
function. There is also the exocrine system.
The Respiratory System
The human respiratory system is a series of organs responsible for
taking in oxygen and expelling carbon dioxide. The respiratory system consists
of the nose, nasopharynx, trachea, and lungs. Red blood cells collect the
oxygen from the lungs and carry it to the parts of the body where it is needed.
During the process, the red blood cells collect the carbon dioxide and
transport it back to the lungs, where it leaves the body when we exhale. The
human body needs oxygen to sustain itself. A decrease in oxygen is known as
hypoxia and a complete lack of oxygen is known as anoxia.
The Nervous System
The nervous system consists of the central nervous system (the
brain and spinal cord) and the peripheral nervous system consists of the nerves
and ganglia outside of the brain and spinal cord. The brain is the organ of
thought, emotion, memory, and sensory processing, and serves many aspects of
communication and controls various systems and functions. The special senses
consist of vision, hearing, taste, and smell. The eyes, ears, tongue, and nose
gather information about the body’s environment.
The Digestive System
The digestive system consists of the mouth including the tongue
and teeth, esophagus, stomach, gut (gastrointestinal tract, small and large
intestines, and rectum), as well as the liver, pancreas, gallbladder, and
salivary glands. The digestive system converts food into small, nutritional,
non-toxic molecules for distribution by the circulation to all tissues of the
body, and excretes the unused residue.
The Integumentary System
The integumentary system consists of the covering of the body (the
skin), including hair and nails as well as other functionally important
structures such as the sweat glands and sebaceous glands. The skin provides
containment, structure, and protection for other organs, but it also serves as
a major sensory interface with the outside world.
The Reproductive System
The human reproductive system consists of the gonads and the
internal and external sex organs. The reproductive system produces gametes in
each sex, a mechanism for their combination, and a nurturing environment for
the first 9 months of development of the infant.
The Lymphatic System
The main function of the lymphatic system is to extract, transport
and metabolize lymph, the fluid found in between cells. The lymphatic system is
very similar to the circulatory system in terms of both its structure and its most
basic function (to carry a body fluid).
No comments:
Post a Comment