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Chapter 5 Academic Knowledge: Medical Terminology and Body Organization
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to build it. It also makes copies and produces its own new cells when
needed.
Factories often use a conveyer belt to sort and transport materials for
production. Endoplasmic reticulum (ehn-doh-PLAZ-mihk rih-TIHK-
yuh-luhm) [endo = within, plasm = structure, ic = pertaining to, reticulo =
network, um = structure], or ER, in the cell is like a conveyor belt on the
production fl oor, moving construction materials (ribosomes) in and out of
the nucleus as they are assembled. Rough ER is covered with ribosomes
from the nucleus for building proteins. Smooth ER builds and stores
fats and carbohydrates and detoxifi es harmful substances. The Golgi
apparatus (GOHL-jee ap-uh-RAT-uhs) is made up of layers of membranes
in the cytoplasm that function like a mailing room. This organelle inspects,
sorts, and packages proteins for use within or removal from the cell.
Cells and factories require energy to operate. Power stations provide
energy to factories. Mitochondria (mI-toh-KAHN-dree-a) are power
stations for cells. They produce adenosine triphosphate (ATP) from
carbohydrates, fats, and proteins. Breaking the bonds of ATP creates
energy for the cell. Muscle cells have more mitochondria than other cells
because their work requires a lot of energy. After cells have used the
available energy, digestive enzymes in the lysosomes (LI-suh-sohmz)
[lysis = destruction] destroy used, dead, and foreign materials that are left
behind, much like a factory janitor cleans up after workers.
Different types of cells have different functions, and each organelle
has a different task within the cell. A cell may have more or fewer
specifi c organelles, such as mitochondria, lysosomes, ribosomes, or cilia,
depending on its job. Which organelles would you expect to fi nd in a
muscle cell? Which organelles would a liver’s cells need to clean the
blood, break down fat, and detoxify alcohol?
Body Tissues and Membranes
Tissue samples and analysis provide important information to
healthcare professionals. If a doctor suspects a disease such as cancer,
she may do a biopsy, obtaining a tissue sample to examine under a
microscope. Histologists [hist = tissue, ologist = specialist in the study of]
work with pathologists, studying these tissues to determine the cause and
treatment of a disease.
There are four main types of tissues, and all four are found
throughout the body:
• Connective tissue includes cartilage, bones, body fat, and blood.
This tissue is important for providing support, absorbing shock,
and storing and transporting nutrients.
• Nervous tissue conducts impulses to and from body organs.
• Muscular tissue is important for movement.
• Epithelial tissue forms the skin that covers the outside of the
body, as well as the membranes that cover the organs and line
body cavities. This tissue forms a protective covering, allows the
absorption of nutrients, helps to fi lter harmful substances out of
the blood, and forms secretions.
tissue
a group of cells of the same
type working together for
the same purpose