The Human Body in Health and Illness, 4th edition Barbara Herlihy Chapter 1: Introduction to the Human Body

Lesson 1-1 Objectives Define the terms anatomy and physiology. List the levels of organization of the human body. Describe the 12 major organ systems. Define homeostasis. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Anatomy and Physiology Anatomy: The branch of science that studies the structure of the body Physiology: The branch of science that describes how the body functions Structure and function are closely related. Use illustrations to discuss relationship between structure and function. For example, the hand’s structure allows the function of grasping. Ask students to give an example of the relationship between structure and function, using a pet or an inanimate object. Pathophysiology is the branch of science that describes the consequences of the improper functioning of the body parts. Fig. 1-1 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

The Body’s Levels of Organization Organization from simple to complex Atoms Molecules Cells Tissues Organs Organ systems Human organism The basic unit of life is the cell. More complex organisms have tissues, organs, and even organ systems. Fig. 1-2 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Major Organ Systems Integumentary Skeletal Muscular Nervous Endocrine Circulatory Lymphatic Immune Respiratory Digestive Urinary Reproductive Groups of organs create organ systems. Each of the 12 human organ systems has a specific function. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Major Organ Systems (cont’d.) The integumentary system forms a covering for the body, helps regulate body temperature, and contains some of the structures needed for sensation. The skeletal system forms the basic framework for the body and protects and supports body organs. The muscular system moves the skeleton and helps maintain body posture. Fig. 1-3 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Major Organ Systems (cont’d.) The afferent peripheral nervous system transmits information to the spinal cord and brain. The brain and spinal cord make and transmit decisions back to the body via efferent peripherals. The circulatory system pumps and transports blood throughout the body, carrying nutrients and oxygen to cells and waste away from them. The endocrine system secretes hormones that regulate body activities such as growth, reproduction, metabolism, and water balance. Fig. 1-3 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Major Organ Systems (cont’d.) The lymphatic system helps defend the body against pathogens and other foreign material. It also plays an important role in fluid balance. The digestive system breaks down the food we eat into substances that can be absorbed by the body. It also eliminates the waste products formed during this process. The respiratory system brings oxygen-rich air into the lungs and removes carbon dioxide–rich air from the lungs. Fig. 1-3 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Major Organ Systems (cont’d.) The urinary system excretes waste products from the body through the urine. It also helps control the amount of water and other substances in the body. The reproductive system enables humans to reproduce. The immune system (not shown) works with the lymphatic system to protect the body from pathogens and foreign substances. Fig. 1-3 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Homeostasis: Staying the Same Homeostasis: The body’s ability to maintain a stable internal environment in response to a changing environment Homeostatic mechanisms help maintain homeostasis. Homeostatic imbalance is associated with various disorders. The word “homeostasis” comes from Greek and Latin words meaning “staying the same”: homeo- is a prefix meaning “same,” and -stasis is a suffix meaning “staying.” Homeostatic functions allow conditions in the body to remain the same when homeostasis is achieved despite external challenges. Hundreds of homeostatic mechanisms help the body maintain homeostasis and help prevent disease or dysfunction caused by homeostatic imbalance. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Lesson 1-2 Objectives Describe the anatomical position. List common terms used for relative positions of the body. Describe the three major planes of the body. List anatomical terms for regions of the body. Describe the major cavities of the body. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Anatomical Position Standing erect Face forward Arms at sides Toes and palms directed forward Remembering that the palms face forward is especially helpful for identifying the bones and muscles of the arms. Anatomical position is the mirror image to the viewer’s position. Fig. 1-4 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Relative Positions Pairs of directional terms Superior and inferior: above/below Anterior and posterior: toward front/toward back Medial and lateral: toward/away midline Proximal and distal: near/far point of attachment Superficial and deep: near/away from surface Central and peripheral: near/away from center Superior means above and inferior below. Anterior means front and posterior back. Medial means toward the midline and lateral away from it. Proximal means near the point of attachment and distal means farther away from it. Superficial means near the surface and deep means below it. Central means center; peripheral means away from it. How is the elbow both distal to the shoulder and proximal to the wrist? The elbow is farther from the point of attachment than the shoulder, but it is nearer the point of attachment than the wrist. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Planes and Sections of the Body Sagittal plane divides the body lengthwise into right and left portions. Frontal plane divides the body into anterior and posterior portions. Transverse plane divides the body horizontally into upper and lower portions. Each plane divides the body with an imaginary line in one direction. If the cut is made exactly down the midline of the body and the right and left halves are equal, this is a midsagittal section. The frontal plane creates the front and back parts of the body. It is also known as the coronal plane. Horizontal and transverse “cuts” are called cross sections. Ask students to demonstrate these planes on a partner with a piece of paper. Fig. 1-5 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Regional Terms Regional terms refer to the different regions or areas of the body. Figure 1-6 illustrates the regional terms for both the anterior and posterior surfaces of the body. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Cavities of the Body Dorsal cavity Ventral cavity Cranial cavity Spinal (vertebral) cavity Ventral cavity Thoracic cavity Pleural cavities Mediastinum Abdominopelvic cavity The thoracic cavity is divided by the mediastinum, which contains the heart, part of the esophagus, trachea, thymus gland, and the blood vessels of the heart. The right and left lungs are located on either side of the mediastinum. They are located in the pleural cavities. The abdominopelvic cavity consists of an upper portion, called the abdominal cavity, and a lower portion, called the pelvic cavity. Thoracic and abdominopelvic cavities are separated by the diaphragm. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Cavities of the Body (cont’d.) Divisions of the abdominopelvic cavity Four quadrants Nine regions The abdominal cavity contains the stomach, most of the intestine, liver, gallbladder, pancreas, spleen, and kidneys. The pelvic cavity contains the remainder of the intestines, rectum, urinary bladder, and internal parts of the reproductive system. The abdominopelvic cavity is quite large. In the health care setting, the surface of the abdominopelvic cavity is often described in terms of quadrants and regions. Fig.1-8 Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.