Learning Objectives

By the end of this section, you will be able to:

  • Identify the 11 systems of the human body and their functions
  • Identify key organs and tissues of various body systems


In multicellular organisms, cells specialize to perform certain tasks.  A group of cells together form tissues, which in turn make up organs, and then systems.  For example, cardiac tissue is made up of cardiac muscle cells, and the tissue comes together to make an organ, the heart!  The heart is, in turn, part of the cardiovascular system.

Table 3.4 lists the eleven systems of the human body, with their function and a list of the main organs and tissues that make each one.  Although each system has specific functions or tasks, they all work together to maintain a stable environment in the body – homeostasis.  As an example of how closely linked the systems are, let’s consider the blood.  It is part of the cardiovascular system, however it also carries nutrients (digestive) and oxygen (respiratory) to the cells, carries hormones throughout the body (endocrine), and removes waste produced by the kidneys (urinary).
Table 3.4 Systems of the Human Body, their Main Organs and Tissues, and Function
System Organs/Tissues Function
Circulatory (Cardiovascular) heart, arteries, veins, capillaries, blood carries oxygen, carbon dioxide and nutrients
Digestive mouth, esophagus, liver, stomach, small intestine, large intestine, anus Ingests and digests food, to get nutrients, and eliminates waste
Endocrine thymus, adrenal gland, pancreas, hypothalamus, pituitary gland, thyroid gland maintains homeostasis
Integumentary hair, skin, nails protects body from injury, infections and other external factors
Lymphatic lymph nodes, thymus, spleen, appendix, bone marrow returns fluid to the body, and contributes to immunity
Muscular skeletal muscles movement and posture
Nervous brain, spinal cord, nerves detect stimuli and directs responses
Reproductive (male and female) females – ovaries, uterus, vagina 

males – prostate gland, seminal vesicles, vas deferens, penis, testis

produces sex hormones and gametes for reproduction
Respiratory lungs, trachea, larynx, pharynx, nasal cavity supplies blood with oxygen and eliminates carbon dioxide
Skeletal bones, cartilage movement, protecting organs, giving shape and size to the body
Urinary kidney, bladder, ureter, urethra removes waste from blood and excretes urine, regulates pH and chemicals of blood
File:Organ Systems I.jpg
Figure 3.15 Systems of the Human Body.


File:Organ Systems II.jpg
Figure 3.16 Systems of the Human Body.


The human body is comprised of a number of different systems, each responsible for specific tasks, but working together to maintain homeostasis.

Media Attribution

  • Figure 3.15 & 3:16 Betts, G. J., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., Korol, O., Johnson, J. E., Womble, M. & DeSaix, P. (2015). Anatomy and Physiology (section 1.2) . OpenStax. CC BY


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NSCC Concepts of Biology II BIOL 1047 Copyright © 2022 by Nova Scotia Community College is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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