chapter 4 Flashcards
, A group of similar cells (and their intercellular substance) specialized to perform a specific function. Primary tissue types of the body are epithelial, connective, muscle, and nervous tissue
tissue
A part of the body formed of two or more tissues and adapted to carry out a specific function. The stomach and the heart are examples of organs.
organ
A group of organs that together serve a broad function important to the survival of an organism or species.
organ system
What are epithelial tissues? Where are they located?
epithelial tissues consist of sheets of cells that line or cover various surfaces and body cavities. Two epithelial tissues that you can easily see are your skin and the lining of your mouth. Other epithelial tissues line the inner surfaces of your digestive tract, lungs, bladder, blood vessels, and the tubules of your kidneys.
Differentiate between a simple and stratified epithelium (think stratum)
A simple epithelium is a single layer of cells, whereas a stratified epithelium consists of multiple layers (or strata). Simple epithelium is so thin that molecules can pass through it easily. Stratified epithelium is thicker and provides protection for underlying cells.
Differentiate between exocrine and endocrine glands
Exocrine glands (exo- means “outside” or “outward”) secrete their products into a hollow organ or duct. Examples of exocrine glands are the glands in your mouth that secrete saliva, glands in your skin that excrete sweat, and glands in your stomach that produce digestive acid
Endocrine glands (endo- means “within”) secrete substances called hormones into the bloodstream. One endocrine gland is the thyroid gland, which secretes several hormones that help regulate your body’s growth and metabolism.
Differentiate between the following cellular junctions:
● Tight junctions seal the plasma membranes of adjacent cells so tightly together that nothing can pass between the cells. Tight junctions are particularly important in epithelial layers that must control the movement of substances into or out of the body. Examples include the cells that line the digestive tract (which bring in nutrients) and the bladder (which stores urine), and the cells that form the tubules of the kidneys (which remove waste products from the body).
● Adhesion junctions, sometimes called “spot desmosomes,” are looser in structure. The protein filaments of adhesion junctions allow for some movement between cells so that the tissues can stretch and bend. Adhesion junctions in the epithelium of your skin, for instance, allow you to move freely.
● Gap junctions represent connecting channels made of proteins that permit the movement of ions or water between two adjacent cells. They are commonly found in the epithelial cells in the liver, heart, and some muscle tissues.
Describe the function of connective tissues.
Connective tissue supports the softer organs of the body against gravity and connects the parts of the body together. It also stores fat and produces the cells of blood
Differentiate between these protein fiber types in connective tissues:
- Collagen fibers, made of protein, confer strength and are slightly flexible. Most fibrous connective tissues also contain thinner coiled
- elastic fibers, made primarily of the protein elastin, which can stretch without breaking
- Some fibrous connective tissue also contains thinner fibers of collagen, called reticular fibers, that interconnect with each other. The reticular fibers often serve as an internal structural framework for some of the soft organs such as the liver, spleen, and lymph nodes
cells responsible for producing and secreting the proteins that compose the collagen, elastic, and reticular fibers
fibroblasts
Differentiate between loose and dense connective tissue.
Loose, Mostly collagen and elastin fibers in no particular pattern; more ground substance, Flexible but only moderately strong, Surrounds internal organs, muscles, blood vessels
Dense, Mostly collagen in a parallel arrangement of fibers; less ground substance, Strong, In tendons, ligaments, and the lower layers of skin
Primarily collagen fibers in a ground substance containing a lot of water
Maintains shape and resists compression Embryonic tissue that becomes bone. Also the nose, vertebral disks, and the lining of joint cavities
Cartilage
Primarily hard mineral deposits of calcium and phosphate Very strong Forms the skeleton
bone
Red blood cells, white blood cells, platelets, and plasma
Transports materials and assists in defense mechanisms
Within cardiovascular system
Blood
Primarily adipocytes cells filled with fat deposits Stores energy in the form of fat Under the skin, around some internal organs
Adipose
What is the main function of muscle tissue?
Muscle tissue consists of cells that are specialized to shorten, or contract, resulting in movement of some kind. Muscle tissue is composed of tightly packed cells called muscle fibers. The fibers are generally long and thin and aligned parallel to each other. The cytoplasm of a muscle fiber contains proteins, which interact to make the cell contract.
Skeletal muscle tissue connects to tendons, which attach to bones. When skeletal muscles contract, they cause body parts to move. The individual cells, also called fibers, are too small to be seen with the naked eye, but they may be as long as the entire muscle (Figure 4.6a). Each muscle cell has many nuclei, a phenomenon that happens because many young cells fuse end-to-end during development, producing one long cell.
Skeletal muscle
Cardiac muscle tissue (Greek kardia means “the heart”) is found only in the heart. The individual cells are much shorter than skeletal muscle fibers, and they have only one nucleus (Figure 4.6b). Like skeletal muscle, the cells are arranged parallel to each other. Cardiac muscle cells are short and blunt-ended, with gap junctions between the ends of adjoining cells. The gap junctions represent direct electrical connections between adjoining cells, so when one cell is activated it activates its neighbors down the line. Because of these gap junctions, the entire heart contracts in a coordinated fashion.
Cardiac muscle
Smooth muscle tissue surrounds hollow organs and tubes, including blood vessels, digestive tract, uterus, and bladder. These slim cells are much smaller than skeletal muscle cells and have only one nucleus, like cardiac muscle (Figure 4.6c). The cells are aligned roughly parallel to each other. In blood vessels, they are generally aligned in a circular fashion around the vessel. When smooth muscle cells shorten, the diameter of the blood vessel is reduced.
Smooth muscle
What is the main function of nervous tissue?
Nervous tissue consists primarily of cells that are specialized for generating and transmitting electrical impulses throughout the body. It forms a rapid communication network for the body. Nervous tissue is located in the brain, the spinal cord, and the nerves that transmit information to and from various organs. An entire chapter is devoted to the nervous system, so we describe nervous tissue only briefly here.
What are the function of the following parts of a neuron:
(1) the cell body, where the nucleus is located; (2) dendrites, numerous cytoplasmic extensions that extend from the cell body and receive signals from other neurons; and (3) a long extension called an axon that transmits electrical impulses over long distances.
What is the function of a glial cell?
glial cell that does not transmit electrical impulses. Glial cells play a supporting role by surrounding and protecting neurons and supplying them with nutrient
are structures composed of two or more tissue types joined together that perform a specific function or functions.
Organ
are groups of organs that together serve a broad function that is important to survival either of the individual organism or a species.
Organ System
