Physiology

Template:StubPhysiology is the study of how organs function in anorganism.

Human physiology: Eleven systems

Human physiology and anatomy classifies organs into eleven systems. They are Circulatory, Immune/Lymphatic, Skeletal, Muscular, Digestive/Excretory, Endocrine, Respiratory, Reproductive, Nervous/Sensory, Integumentary, and Urinary. Some physicians consider the nervous and sensory to be two distinct systems, and consider the skeletal and muscular as one (the Skeletomuscular), thus retaining the number of eleven systems total.

Circulatory

The heart, arteries, veins, and capillaries.

Skeletal

Bones (206 in all); joints, tendons, and cartilage.

Digestive and Excretory

• Esophagus--carries food and fluids from mouth to stomach
• Stomach--digests food
• Pylorus--opens or closes the stomach
• Small intestine--allows fluids and nutrients to be absorbed into the system, by means of villi
• Cecum or caecum--absorbs more fluid into the system
• Colon or large intestine--concentrates waste for elimination
• Rectum--expels waste from the body

Endocrine

Glands including the thyroid, pituitary, pineal, gonads, thymus, pancreas, and adrenals. They produce hormones to facilitate metabolic, reproductive, and circadian cycles.

Reproductive

The reproductive system facilitates procreation, and is closely associated with the endocrine system.

• Female reproductive organs
• Uterus--Carries the fetus during gestation
• Ovaries--Produce ova; also produce hormones and are therefore sometimes classified as endocrine organs. Homologous to the testicles in the male.

• Male reproductive organs
• Testicles--Produce spermatozoa; also produce hormones and are therefore sometimes classified as endocrine organs. Homologous to the ovaries in the female.
• Prostate--Produces fluids to supply nutrients to the spermatozoa; also closes the bladder.

Each male reproductive organ is homologous, or directly corresponding, to a particular female reproductive organ.