Human Organ Systems and Skin Function

Definition of Physiology

• Physiology is the science of the normal functions and phenomena of living things.

Levels of Organization

• The human body is organized at multiple levels:
• Organismal level: The entire human body.
• Organ system level: Organ systems consist of different organs that work together closely.
• Organ level: Organs are made up of different types of tissues.
• Tissue level: Tissues consist of similar types of cells.
• Cellular level: Cells are made up of molecules.
• Chemical level: Atoms combine to form molecules.

The Primary Tissues

• There are four major types of tissues in the human body:
• Epithelial tissue: Covers body surfaces and lines body cavities.
• Connective tissue: Binds and supports body parts.
• Muscle tissue: Causes body parts to move.
• Nervous tissue: Responds to stimuli and transmits impulses from one body part to another.

Epithelial Tissues

• Epithelial tissue covers entire body surface and most of the body's inner cavities.
• Functions of epithelial tissue include protection from injury and drying out, and secretion of mucus.

Connective Tissues

• Connective tissue connects organs and provides support and protection.
• Functions of connective tissue include binding structures together, filling up spaces, and storing fat.

Muscle Tissues

• There are three types of muscle tissue:
• Skeletal muscle: Striated, voluntary, and attached to bones.
• Smooth muscle: Non-striated, involuntary, and found in internal organs and blood vessels.
• Cardiac muscle: Striated, involuntary, and found only in the heart.

Nervous Tissues

• Nervous tissue is specialized to form nerves, brain, and spinal cord.
• Functions of nervous tissue include conducting electrical and chemical messages along special cells called neurons.

Glands

• Glands are cells or collections of cells that secrete chemicals.
• There are two types of glands:
• Exocrine glands: Secrete into ducts, e.g., the gall bladder and sweat glands.
• Endocrine glands: Secrete chemicals (especially hormones) into the bloodstream, e.g., the pituitary gland and pancreas.

Glial Cells

• Glial cells are cells that surround nerve cells.
• Functions of glial cells include supporting, protecting, and nourishing nerve cells.

Organs

• Organs are made up of one or more types of tissues.
• Examples of organs include the heart and skin.

Human Organ Systems

• Each organ system is located in a specific location and has specific functions.
• Organ systems contribute to maintaining a stable internal environment (homeostasis).
• Examples of organ systems include the digestive system and circulatory system.

Learn about the largest organ, skin, and its functions. This quiz also covers human organ systems, their locations, and roles in maintaining a stable internal environment.