Body Organization Terms

The body is composed of systems, a system is composed of organs, and organ is

composed of tissues, and tissues are composed of cells. The major body structure is

built from smallest to largest: cells → tissues → organs → systems → body.

Cells- fundamental unit of all living things. All the tissues and organs in the body are composed of cells. Cells(undifferentiated) perform functions for the body, such as reproduction, hormone secretion, energy production, and excretion. Special (differentiated) cells carry out very specific functions, such as contraction of the muscles (muscle cells), and electrical impulse transmissions (nerve cells).

The nucleus of the cell contains our DNA, which consists of 23 pairs of chromosomes from our mother and father. The cell membrane is the outer layer of the cell that holds it together. Cytoplasm is the gel-like substance inside of every cell.

All cells begin as stem cells, or undifferentiated cells. As they mature, they are assigned to a specific body system, and then become specialized, or differentiated cells. When a group of cells start working together, they are then known as tissue.

Tissues- Cells working together to perform a specific activity are known as tissues. The body has four types of tissue: muscular, epithelial, connective, and nervous.

Muscle tissue- produces movement in the body through contraction, or shortening in length, and is composed of individual muscle cells. Three types of muscle tissue are: skeletal- attached to bone; smooth- internal organs (intestine, uterus, and blood vessels); cardiac- heart.

Epithelial tissue- found throughout the body that covers and lines body structures. This type of tissue acts as a protective barrier, absorbs substances (nutrients from intestine), secretes substances (sweat, oil), and excretes waste (ureters, urethra). 

Connective tissue- supports and protects body structures. Examples include bone- provides structural support for the whole body; cartilage- shock absorber in joints; tendons- tightly connects muscles to bone; adipose (fat)- provides protective padding around body structures. 

Nervous tissue- made up cells that are called neurons. This tissue forms the brain, spinal cord, and a network of nerves throughout the entire body; allows for electrical impulses to send messages between the brain and the rest of the body.

Terms to Know

Cyt/o= cell

-logy= study of

-plasm= formation

-al= pertaining to

-ar=pertaining to

-ous= pertaining to 

-ac= pertaining to

epi- upper; above cardi/o-heart

Adip/o= fat

chondr/o= cartilage

crin/o= to secrete

Derm/o= skin

hist/o= tissue

neur/o= nerve

-ose= pertaining to

spin/o= spine

my/o= muscle

-lytic= destruction-

pathy= disease

Diseases 

Cancer- a disease caused by an uncontrolled division of abnormal cells in a part of the body.

Sickle cell anemia- inherited disease that affects the shape of red blood cells, which carry oxygen to all parts of the body.

Anemia- lack of iron in your blood.

Leukemia- blood cancer in which malignant white blood cells multiply inside your body’s bone marrow.

Diagnostic Procedures 

Complete Blood Count (CBC)- measures the number of red blood cells (RBC), white blood cells (WBC), and platelets (PLT). Each of these types of blood cells performs important functions, so determining their levels can provide important health information.

Prothrombin Time- blood test that indicates blood coagulation abilities by measuring how long it takes for a clot to form after prothrombin has been activated.

Blood Culture and Sensitivity- blood test that allows the sample to incubate in a laboratory to check for bacterial growth.

Pap Smear- a test carried out on a sample of cells from the cervix to check for abnormalities that may be indicative of cervical cancer.

Medical Specialties

Biologist- an expert in or student of the branch of science concerning living organisms.

Geneticist- an expert in or student of heredity and the variation of inherited characteristics.

Hematologist- healthcare providers who specialize in diagnosing, treating, and managing diseases that affect your blood, bone marrow and lymphatic system.