Medical Terminology, Basic Human Structure, Diseases, and Disorders

Chapter 22


Medical Terminology, Basic Human Structure, Diseases, and Disorders




Unit Objectives


On completion of this unit, you will be able to:




Introduction to Medical Terms


Most medical terms are made up of Greek (e.g., nephrology) and Latin (e.g., maternal) words; however, some terms, such as triage and lavage, have been adapted from modern languages such as French. Two other sources of medical terms include acronyms and eponyms. An acronym is a word formed from the first letters of major terms in a descriptive phrase, such as laser (light amplification by stimulated emission of radiation). An eponym is a name given to something that was discovered by or is identified with an individual. The Pap smear (Dr. Papanicolaou) and Lou Gehrig disease (amyotrophic lateral sclerosis [ALS]) are two examples of eponyms.


Although a background in Greek or Latin is not necessary to learn the meaning of medical terms, it is necessary to learn the English translation of the Greek or Latin word parts. In this course of study, the parts of the word are memorized rather than the whole word. By learning word parts, one will be able to build words according to a given definition and break down words into word parts to determine their meaning. For example, in the medical term



nephr is the word part that means “kidney” and -ectomy is the word part meaning “surgical removal.” Thus, nephrectomy means “surgical removal of the kidney.” Once one has memorized the meanings of the word parts (nephr- and -ectomy), one will know their meanings when they appear in other medical terms.


In the preceding example, one can define the term by literally translating it. However, a few medical terms have implied meanings.


For example, the word



literally translated means “without” (an-) “blood condition” (-emia). However, the correct interpretation of anemia—an implied meaning—is a deficiency of red blood cells (RBCs). Knowledge of the meanings of the word parts for a medical term with an implied meaning takes one almost, but not quite, to the exact meaning of the term.


Medical terms are used instead of English words because one medical word says what it would take many English words to say. For example, nephrectomy means “surgical removal of the kidney.” Medical terms are efficient and factual, they save space, and they often describe a situation or procedure more exactly.


Pronunciation of medical terms varies. What is acceptable pronunciation in one part of the country may not be used in another part of the country; therefore flexibility is necessary in the pronunciation of medical terms.


Correct spelling is absolutely necessary to avoid the incorrect use of a term. Ileum (portion of small intestine) and ilium (one of the bones of the hip) are two examples of terms close in spelling, yet anatomically diverse in meaning.


As you begin working with medical terminology, you may feel overwhelmed at the task of learning this new language. However, repeated use of the word parts will assist you in building your vocabulary, and soon you will be using medical terms fluently in your everyday speech. Many students employ the use of mnemonics (memory-aiding devices) to remember the word parts. For example, entero is the word part for “intestine.” One might think of “digested food entering the intestine” and more easily recall the meaning of entero. Similarly, ileum of the small intestine is spelled with an e and one might associate “eating” with the intestine and not mistake this term with ilium, the bone in the hip.


This unit deals with word parts and how they are used together to form medical terms. Remember: It is important for you to master Unit 1 before proceeding to Unit 2, and so forth, because each unit is a continuation of the previously studied units.



Word Parts


In this course of study, the development of a medical vocabulary is based on memorizing parts of words rather than whole words. Word part is the term that will be used to describe the components of words. To build or analyze (divide into parts) medical terms, you first must learn the following four word parts:







Combining Vowel


The combining vowel, usually an o, is used between two word roots or between a word root and a suffix to ease pronunciation. Three guidelines are followed in using a combining vowel.



Note: A combining form, not a true word part, is simply the word root separated from its combining vowel with a slash mark. For example, gastr / o is a combining form. Although o is the most commonly used combining vowel, a, e, and i also may be used. Throughout this chapter, the word roots are listed in combining forms.






























































Word Root Meaning
cardi / o heart
cyt / o cell
electr / o electricity, electrical activity
enter / o intestine
gastr / o stomach
hepat / o liver
nephr / o kidney
Prefixes Meaning
intra- within
epi- upon
sub- under, below
trans- through, across, beyond
Suffixes Meaning
-ectomy excision, surgical removal
-gram record, x-ray image
-ic pertaining to
-itis inflammation
-logy study of


Analyzing Medical Terms


To analyze medical terms, divide the term into word parts with the use of vertical slashes and identify the word part by labeling it as follows:
















P prefix
WR word root
S suffix
CV combining vowel

After labeling and identifying, simply define the medical term according to the definitions of the word parts.



image EXERCISE 1


Analyzing medical terms: Analyze the following medical terms by dividing each into word parts and writing P, WR, S, or CV above the appropriate part, as in the following examples. Use the earlier list to help you identify word parts.


Example 1: gastroenteritis




















WR CV WR S
gastr / o / enter / itis
stomach   intestine inflammation of


image


Example 2: intragastric







Unit Objectives


On completion of this unit, you will be able to:



1. Describe the function and structure of body cells.


2. Identify and describe the function of four types of tissue


3. Explain the structure of an organ and the structure of a system.


4. List five body cavities, and name a body organ contained in each cavity.


5. List the four quadrants and nine regions of the abdominopelvic cavity.


6. Define the anatomical position and the directional terms outlined in this unit.


7. List four functions of skin.


8. List the seven signs of cancer, and describe first-, second-, and third-degree burns.


9. Define abscess, laceration, abrasion, gangrene, infection, and decubitus ulcer.


10. Read the objectives related to medical terminology, and demonstrate ability to meet the objectives by completing Exercises 1 through 6.


11. Define the unit abbreviations.



Body Structure (Anatomy) and Function (Physiology)


Body Cells


The cell is the basic unit of all living things (Fig. 22-1). The human body is made up of trillions of cells. Cells perform specific functions, and their size and shape vary according to function. Bones, muscles, skin, and blood are all made up of different types of cells. Body cells are microscopic; approximately 2000 are needed to make an inch (although a single nerve cell may be several feet long). Cells are constantly growing and reproducing. Such growth is responsible for the development of an embryo into a child and a child into an adult. This growth is also responsible for the replacement of cells that have a relatively short life span and cells that are injured, diseased, or worn out.


image
Figure 22-1 Parts of a body cell.

To visualize the structure of a cell, we can diagrammatically compare the three main parts of the cell with the three parts of an egg: the eggshell, the egg white, and the egg yolk.






Body Tissues


A tissue is made up of a group of similar cells that work together to perform particular functions (Fig. 22-2). Tissues may be categorized into the following types:


image
Figure 22-2 Types of tissues.




Body Systems


A body system is made up of a group of organs that work closely together in a common purpose to perform complex body functions (Fig. 22-3). For example, the urinary system is made up of the following organs: kidneys, ureters, urinary bladder, and urethra. Its main function is to remove wastes from the blood and eliminate them from the body. Other body systems include the digestive, musculoskeletal, nervous, reproductive, endocrine, circulatory, respiratory, sensory, and integumentary systems. Some organs are a part of more than one system. The pharynx, for example, is part of both the digestive and the respiratory systems. In the digestive system the pharynx allows for the passage of food; in the respiratory system it allows for the passage of air.


image
Figure 22-3 Organization of the body.

Homeostasis is the maintenance of a stable, relatively constant environment within body cells and tissues. Stability of the body’s normal volume, temperature, and chemicals is effected by the successful harmony of the organ systems and is regulated by the nervous and endocrine systems. Failure to keep the body systems in homeostasis results in disease.



Body Cavities


Large spaces within the body that contain internal organs, or viscera, are called body cavities (Fig. 22-4). The two major body cavities are the dorsal cavity (near the back) and the ventral cavity (near the front).


image
Figure 22-4 The body cavities.



Ventral Cavity


The ventral cavity is composed of the thoracic (or chest) cavity and the abdominopelvic cavity.



• Thoracic cavity: The chest cavity contains additional spaces, including right and left pleural cavities and the mediastinum. Organs within the thoracic cavity include the heart, lungs, trachea, esophagus, thymus gland, and major blood vessels.


• Right and left pleural cavities: Double-walled sacs that create spaces that surround the lungs.


• Mediastinum: Space that contains the heart, trachea, esophagus, thymus gland, and major blood vessels.


• Abdominopelvic cavity: This space is divided into the abdominal cavity and the pelvic cavity.


• Abdominal cavity: Upper portion of the abdominopelvic cavity. This space contains the stomach; most of the intestines; and the kidneys, ureters, liver, pancreas, gallbladder, and spleen. The abdominal cavity is separated from the thoracic cavity by a muscle called the diaphragm.


• Pelvic cavity: Lower portion of the abdominopelvic cavity. This space contains the bladder, urethra, reproductive organs, part of the large intestine (sigmoid colon), and the rectum. The abdominopelvic cavity is divided into four quadrants and nine regions (Fig. 22-5). You will frequently encounter these descriptive terms during your health care employment.


image
Figure 22-5 Division of the abdominopelvic cavity into four quadrants and nine regions.


Directional Terms Pertaining to the Body


Directional terms, which are used to describe a location on or within the body, refer to the patient in the anatomical position. Anatomical position is the point of reference that ensures proper description: body erect, face and feet forward, arms at side, and palms facing forward. In Figure 22-11 (in Unit 3 of this chapter), the skeletal orientation is in the anatomical position.



• Superior (cranial): Pertaining to above. (The eye is located superior to the mouth.)


• Inferior (caudal): Pertaining to below. (The mouth is located inferior to the nose.)


• Anterior (ventral): Pertaining to in front of. (The eyes are located on the anterior of the head.)


• Anteroposterior (AP): Pertaining to front to back. (Directionally moving from the front to the back.)


• Posterior (dorsal): Pertaining to in back of. (The gluteus maximus is posterior to the navel.)


• Posteroanterior (PA): Pertaining to back to front. (Directionally moving from the back to the front.)


• Lateral (lat): Pertaining to the side. (The little toe is lateral to the big toe.)


• Bilateral (bilat): Pertaining to two (both) sides. (Bilateral otitis media [ear infections].)


• Medial: Pertaining to the middle. (The nose is medial to the ears.)


• Abduction: Pertaining to away from. (Spreading the fingers wide apart is an example of abduction.)


• Adduction: Pertaining to toward. (Bringing the fingers together from being spread out shows adduction.)


• Proximal: Pertaining to closer than another structure to the point of attachment. (The elbow is proximal to the wrist.)


• Distal: Pertaining to farther than another structure from the point of attachment. (The fingers are distal to the elbow.)


• Superficial: Toward the surface. (Hair follicles are superficial structures.)


• Deep: Farther from the surface. (The femur is deep to the skin.)


• Prone: Lying with the face downward. (The patient is placed in a prone position for suturing of the back of her head.)


• Supine: Lying on the back. (Supine positioning was required for his sternal puncture.)



Integumentary System


The integumentary system consists of the skin (the largest organ of the body) and accessory structures (hair, nails, and sweat and oil glands) (Fig. 22-6). The skin of an adult may weigh 20 pounds or more. The skin has many functions. The main one is to protect underlying tissues from pathogenic (disease-causing) microorganisms and other environmental hazards. The skin also assists in the regulation of body temperature and the synthesis of vitamin D. As a sensory organ, the specialized receptors of the skin pass messages of pain, temperature, pressure, and touch to the brain.


image
Figure 22-6 The skin.

The thin outer layer of skin is called the epidermis and is composed of epithelial tissue. The cells of the innermost layer produce themselves. As they move toward the surface, the outermost cells are shed. Millions of cells are produced and shed each day. The epidermis contains no blood vessels.


The thick layer directly below the epidermis is called the dermis, or true skin. It is made up of connective tissue and contains blood vessels, nerve endings, hair follicles, and sweat and oil glands.


The subcutaneous tissue (or hypodermis), a thick, fat-containing tissue located below the dermis, serves to connect the skin to underlying muscles, bone, and organs.


Hair provides a protective function; for example, nasal hairs trap foreign particles to prevent them from being inhaled into the lungs. The hair follicle is a pouchlike depression in the skin from which the hair grows to extend above the skin surface. Oil glands (sebaceous glands) connect to the hair follicle through tiny ducts. Each sebaceous gland produces oil (sebum), which lubricates the hair and skin and inhibits bacterial growth.


The sweat glands (sudoriferous glands) are coiled, tubelike structures that are located mainly in the dermis. Each extends to the surface in the form of a tiny opening called a pore. Approximately 3000 pores can be found in the palm of a hand, and 2 million on the body surface. Sweat, a saline fluid, is produced by the sweat glands. As sweat evaporates on the body surface, it cools the body.


Skin color is determined by the amount of melanin in the epidermis of the skin. Skin color varies from pale yellow to black. A condition called albinism results when melanin cannot be formed by melanocytes. An albino can be recognized by the characteristic absence of pigment in the hair, eyes, and skin.



Diseases and Conditions of the Skin and Body Cells


Cancer


Cancer (often abbreviated as Ca) is a disease in which unregulated new growth of abnormal cells occurs. It is normal for worn-out body cells to be replaced by new cell growth and also for new cells to form to repair tissue damage. Normal cell growth is regulated; in cancer, cell division is unregulated, and cells continue to reproduce until a mass known as a tumor, or neoplasm, forms. Skin cancer arises from cell changes in the epidermis and is the most common form of human cancer. Exposure to broad-spectrum ultraviolet (UV) rays of the sun and artificial sources is thought to be an important factor in the development of skin cancer. Basal cell carcinoma and squamous cell carcinoma, two major types of skin cancers, both are very responsive to treatment and seldom metastasize (spread) to other body systems.


Cancerous tumors are malignant, which means they become progressively worse, whereas noncancerous tumors are benign or nonrecurrent. Malignant tumors grow in a disorganized fashion, interrupting body function and interfering with the food and blood supply to normal cells. Malignant cells may metastasize from one organ to another through the bloodstream or the lymphatic system. Malignant melanoma arises from the melanocytes (pigment-producing cells in the skin) and may metastasize to the brain, liver, lung, and other organs.


Cancer consists of many different diseases, and a single cause of abnormal cell division cannot be pinpointed. Genetic factors, steroidal estrogens, cigarette smoking, exposure to carcinogenic substances, and UV rays are believed to be among the causes of cancer.


Detection of cancer requires self-examination, x-ray imaging, blood tests, and microscopic tissue examination. Treatments for patients with cancer include surgery, chemotherapy, radiation, and gene therapy.




Burns


All burns are dangerous if they are not treated properly, because infection can occur and because shock is possible in more serious burns as a result of fluid loss from the skin. Burns are classified according to degree of severity, which reflects the depth of the burn (full or partial thickness) (Fig. 22-7) and the extent of surface area involvement (Fig. 22-8).


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Figure 22-7 First-degree burns damage the epidermis; second-degree burns damage the epidermis and the dermis; third-degree burns damage the epidermis, the dermis, and the subcutaneous tissue.

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Figure 22-8 Surface area involvement of burns. The rule of nines is one method used to estimate the total body surface area (TBSA) burned in an adult. This method divides the TBSA into multiples of 9% (1% for the groin). The Lund-Browder chart is used for infants and children because the surface area of the head and neck is greater than for adults, and the limbs are smaller.






Infection


Infection is the invasion of the body by pathogenic microorganisms that reproduce and multiply, causing disease. Infections may be caused by streptococcal, staphylococcal, or Pseudomonas bacteria; by viruses; or by other organisms. Bacterial infections are treated with antibiotic therapy. Methicillin-resistant Staphylococcus aureus (MRSA) is one of several nosocomial (hospital- or health care setting–acquired) pathogens (see Chapter 14). Often the main mode of transmission of nosocomial infections in the clinical setting is through the hands of health care workers. These pathogens can be found on the skin, in the nose, and in blood and urine. Proper hand cleansing techniques should be reviewed with new employees by the infection control department of the clinical setting to avoid transmission of MRSA.



Decubitus Ulcer


Decubitus ulcer, also known as bedsore or pressure sore, is a vascular condition that arises in patients who sit or lie in one position for long periods of time. The weight of the body, typically over bony projections such as the hips, heels, and ankles, slows blood flow, causing ulcers to form, and infection may develop when microorganisms enter the affected area. The decubitus ulcer, similar to the burn, is categorized according to severity in terms of stages (stage I to stage IV). Beginning as a reddened, sensitive, unbroken patch of skin categorized as stage I, the pressure sore may progress to an open sore (ulcer) for which strict attention to wound care is required. In stage IV the patient may experience full-thickness skin loss with damage to muscle, bone, or other body structures. Periodic body position changes and soft support cushions may help to prevent the onset of pressure sores.



image Review Questions








Medical Terminology Related to Body Structure, Integumentary System, and Oncology


Objectives


On mastery of medical terminology for this unit, you will be able to:




Word Parts


Listed in the following table are the word parts you will be working with in this unit. You will need to memorize each one because you will continue to use them in this chapter and in your work environment. The exercises that follow these lists will assist you in this task. Practice pronouncing each word part aloud.


To review, a word root is the basic part of the word; a combining form is the word root plus a combining vowel (generally an o); a prefix is the modifying word part added to the beginning of a word; and a suffix is the modifying word part added to the end of a word root.





















































Word Roots/Combining Forms Meaning
bi / o (bī′-yo) life
cancer / o, carcin / o (kăn-sĕr-ō) (kar′-sĭn-ō), cancer
cutane/ o (kyū-tā′-nē-ō), skin
cyt / o (sī′-to) cell
dermat / o (dĕr′-mě-tō) skin
derm / o (dĕr′-mō) skin
epitheli / o (ĕp-ī-thē′-lē-ō) epithelium
hist /o (hĭs′-to) tissue
lip / o (lĭp′-ō) fat
onc / o (ŏn′-kō) tumor
path / o (păth′-ō) disease
sarc / o (sar′-cō) connective tissue, flesh
trich / o (trĭk′-ō) hair
ungu / o (ŭng′-ŭ-ō) nail
viscer / o (vĭs′-ĕr-ō) internal organs

Many of the suffixes presented in this course of study are made up of word roots and suffixes. For example, the suffix -logy (or -ology) is built from log (word root for “study”) plus -y (suffix). For learning purposes, these will be studied as suffixes and analyzed as a single word part.









































Prefixes Meaning
sub- under, below
trans- (trăns) through, across, beyond
Suffixes Meaning
-al, -ous pertaining to
-genic (jĕn′-ĭk) producing, originating, causing
-itis (ī′-tĭs) inflammation
-oid (oyd) resembling
-logist (lŏ′-jĭst) one who specializes in the diagnosis and treatment of (doctor)
-logy (lŏ′ -jē) study of
-oma (ō′-mah) tumor
-opsy (ŏp′-sē) to view


image EXERCISE 1


Define each combining form listed.




image EXERCISE 2


Define each suffix and prefix listed.





image EXERCISE 3


Write the word parts for each definition. Indicate which word parts are suffixes by writing S in the space provided, indicate which word parts are word roots or combining forms by writing WR/CF in the space provided, and indicate which word parts are prefixes by writing P in the space provided.


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Apr 8, 2017 | Posted by in MEDICAL ASSISSTANT | Comments Off on Medical Terminology, Basic Human Structure, Diseases, and Disorders

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