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Natural Science - Year I

Unit 22: Leonoardo da Vinci and Anatomy

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Science Weblecture for Unit 22

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Science Lecture for Unit 22: Human Anatomy I

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The Study of Anatomy

Human Anatomy: Introduction to Skin, Bones, and Muscles

Anatomy looks at the organs and systems of the body in terms of structure. An anatomist tries to identify the different organs from their appearance and location. The ability to do this more accurately, thanks to the illustrations in texts like those of Leonardo and Vesalius (whom we study in the next unit), made it possible for scientists in different areas to compare and communicate their observations. As their observations became more detailed, they also became more interested in how the different organs and tissues of the body function. This study of function is physiology.

The modern approach to learning about the human body usually starts with cell theory, then goes on to discuss how cells come together to form tissues with specialized functions, which are then combined into organs and organ systems. The function of the systems is the study of physiology; the identification of the systems and their structure, especially in comparison to similar organisms in other animals, is anatomy. Since historically, the progression was from anatomy to physiology, tissue studies, and cell theory, we will be learning the subject "out of order", from the middle up, then top down, rather than the bottom up. Because of this, we need to keep in mind that ultimately, all the organs of the body do rely on the basic structures and functions of cells, but we will cover those details later.


Modern biologists identify four kinds of tissue that make up the organs of the different organ systems.

Study J. Kimball's diagram of the different types of Animal Tissue cells.

[1 page.]

  • How are the shapes of the cells different in different kinds of tissue?
  • Notice that the epithelial tissue is only one cell layer deep? Why is this necessary if the epithelial tissue is used in the surface lining of the stomach?

Organs and organ systems

Now we can take a closer look at anatomy, the identification of organ systems and organs within the human body. The early anatomists divided the human body into four regions: the head, the neck, the trunk, and the extremities. The head houses the brain and most of the sensory organs, the eyes, ears, nose, and tongue. The neck is a connector filled with tubes carrying air, blood, and messages. The trunk houses the organs which process food (the digestive system) and air (lungs and bronchial passages) and supply the body with nutrients (heart and circulatory systems). These vital organs are protected from injury by special bones (the rib cage and hip bones). The muscles and bones of the appendages--the arms and legs--are primarily for movement and support.

The major systems are:

Notice that these systems are not completely separate and distinct, but overlap. We find muscles with functions dedicated to a single system, and glands that produce hormones affecting multiple systems.

Study the skeletal, muscle, and nervous systems Think Quest's Tour of the Human Body. This is a student-developed website with basic information on each of the body's systems. For this week, concentrate on bones, muscles, and nerves.

[1 page.]

  • Study the main bones of the skull, shoulder, rib cage, arm, hip, leg, hand and foot and be able to identify the cranium, clavicle, scapula, sternum, ribs, humerus, vertebrae, radius, ulna, phalanges, pelvis, femur, tibia, and fibula.
  • What are the three layers of bone? What is the purpose of each?
  • What connects two bones together?
  • How does a ball and socket joint like the shoulder work?
  • What is a hinge joint like the elbow work?
  • Ligaments are tough connective tissue that join bones together: are they elastic?
  • Why does your body have immovable joints?
  • What is cartilage?
  • How is bone itself structured?
  • What are the three kinds of muscle tissue?
  • Where is each kind found?
  • What connects muscles to bones?
  • How does a muscle contract?
  • Why do muscles work in pairs to move your arms, legs, and fingers?
  • Where is the central nervous system? What does it do?
  • Where is the peripheral nervous system? What does it do?
  • What are the "five senses"?
  • How does the brain receive information through your senses?
  • How does the brain control different parts of your body?
  • What are the parts of a nerve cell?
  • How does the nervous system and the endocrine system work together to control your body?

Study/Discussion Questions:

Further Study/On Your Own