Download chapter 4-body structure

CHAPTER 4-BODY STRUCTURE
I. In studying the human body, we will start with the simplest structure and move to the more
complex. Essentially, the body is organized from its smallest element, the CELL, to the largest
element, SYSTEMS.
II. Levels of Organization in the Human Body:
A. Cells-the smallest living form of matter. Cells make up the lowest level of organization
in the human body. They are basically the smallest living things that are alive.
1. There are numerous types of cells in the human body-all of which perform
specific functions for the body.
2. Cells contain three major parts:
a. An outer covering around the cell known as the Cell Membrane. This
structure gives a cell its shape and regulates the materials that enter or
exit the cell.
b. The Nucleus-regulates the daily activities of the cell and stores DNA for
the cell.
c. Organelles-small structures that perform specific functions for the cell.
Examples of organelles include the mitochondria which are involved in
producing energy for the cell and lysosomes which aid in digesting
certain molecules in the cell. The organelles are surrounded by a liquid
material known as cytoplasm.
3. CytologyB. Tissues-groups of cells that work together to perform similar functions. There are Four
Major Types of Tissues in the Human Body:
1. Epithelial Tissues-covers and lines internal and external surfaces of the body.
2. Connective Tissue-holds and connects body parts together. Examples include
ligaments, cartilage, bone and blood.
3. Muscle Tissue-can contract (shorten) to produce movements. There are three
types of muscle tissue: skeletal, cardiac and smooth.
4. Nervous Tissue-generates and carries electrical signals (impulses) throughout
the body.
C. Organs-groups of tissues that work together to perform similar functions. Examples of
organs include: the heart, the brain and the kidneys.
D. Systems-groups of organs that work together to perform similar functions. Systems
comprise the highest level of organization in the human body.
E. Organism-a living individual. This is the highest level or organization.
III. ANATOMICAL POSITION-standard reference position for people in the health care field.
A. In this position, a person stands erect, eyes facing forward, arms at the sides of the body,
palms facing forward and feet flat on the floor.
IV. BODY PLANES-imaginary lines that are used to divide the body (or an organ) into sections. The
major planes include:
A. Frontal Plane-divides the body into anterior and posterior positions.
B. Sagittal Plane-divides the body into left and right sections.
C. Transverse Plane-divides the body into superior and inferior portions.
D. Oblique Plane-divides the body at an angle.
V. BODY CAVITIES-confined spaces in the body that are covered by protective membranes and
that contain glands, organs and other necessary structures.
A. There are Two Major Body Cavities:
1. The Dorsal Body Cavity-along the back of the body. It is divided into two sections:
a. The Cranial Cavity-contains the brain.
b. The Spinal Cavity-contains the spinal cord.
2. The Ventral Body Cavity-along the front of the body. It is also divided into two
sections:
a. The Thoracic Cavity-contains the lungs and heart.
b. The Abdominal Cavity-contains the digestive, reproductive and urinary
structures.
VI. REGIONS and QUADRANTS
A. Often times, health professionals divide the body into Four Major Quadrants:
1. Right Upper Quadrant
2. Right Lower Quadrant
3. Left Upper Quadrant
4. Left Lower Quadrant
B. The Quadrants can be further subdivided into smaller Regions. Be able to identify the
Major Regions from page 46.
VII. DIRECTIONAL TERMS-know the terms from page 47.
VIII. COMBINING FORMS/SUFFIXES/PREFIXES-know from pages 50-56.
IX. PATHOLOGY-the general study of disease.
A. A disease occurs when part or all of the body is unable to function effectively.
B. Signs-indicators that can be observed by someone else. Examples of signs:
C. Symptoms-indicators that cannot be observed. Examples include:
D. Etiology-the study of the cause or origin of a disease.
1. Possible Causes of Disease:
a. Metabolic
b. Infectious
c. Congenital
d. Hereditary
e. Environmental
f. Neoplastic
E. Any disease of an unknown cause is said to be idiopathic.
F. Diagnosis-determining the cause of a disease.
G. Prognosis-predicting the course of a disease and it probable outcome.
X. MEDICAL IMAGING TECHNIQUES-used to look at internal structures and to identify damage
to the body or diseases associated with the body. Types of Imaging Techniques:
A. Radiography (X-Rays)
B. Computed tomography scan (CT)
C. Magnetic Resonance Imaging (MRI)
D. Positron Emission Tomography (PET)
E. Ultrasound
XI. DISEASES, CONDITIONS, PROCEDURES-pages 58-63.