Body Structure Key Terms Flashcards
chromatin
Structural component of the nucleus, composes of nucleic acids and proteins. Chromatin condenses to form chromosomes during cell division
chromosome
Threadlike structures within the nucleus composed of deoxyribonucleic acid (DNA) that carries hereditary information encoded in genes. Each sperm or egg has 23 unpaired chromosomes. After fertilization, each cell of the embryo has 46 chromosomes (23 pairs). In each pair oh chromosomes, one chromosome is provided by the father and the other by the mother.
deoxyribonucleic acid (DNA)
molecule that holds genetic information capable of replicating and producing an exact copy whenever the cell divides.
metabolism
sum of all physical and chemical changes that take place in a cell or organism; metabolism includes the building up (anabolism) and breaking down (catabolism) of body constituents.
5 levels of organization in the body
cells, tissue, organs, systems and organisms
3 main structures of cells
cell membrane, cytoplasm and nucleus
cell membrane
acts as a barrier that supports and protects intracellular contents
cytoplasm
jellylike matrix of proteins, salts, water, dissolved gases and nutrients
organelles
located inside cytoplasm; cellular structure that provides a specialized function such as nucleus (reproduction), ribosomes (protein synthesis), Golgi apparatus (removal of material from cell) and lysosomes (digestion). The membranes of many organelles act as sites of chemical reactions.
nucleus
responsible for metabolism, growth and reproduction; carries genetic blueprint of the organism
tissue
composed of similar cells that perform specialized or common functions; 4 types of tissue
histology
study of tissues
4 types of tissues
Epithelial, connective, muscle and nervous
epithelial tissue
covers organs, lines cavities and canals, forms tubes and ducts, provides the secreting portions of glands and makes up the outer layer(epidermis) of the skin. It is composed of cells arranged in a continuous sheet consisting of one or more layers.
connective tissue
supports and connects other body tissues; various types of connective tissue including cartilage, adipose, bone, elastic fiber and even blood