APII: Tissue types Flashcards
(27 cards)
What are the four main types of tissue in the human body?
- Epithelial Tissue
- Connective Tissue
- Muscle Tissue
- Nervous Tissue
What is the primary function of epithelial tissue?
Covers body surfaces, lines body cavities, and lines hollow & tubular organs
What is a characteristic of cells in epithelial tissue?
Cells are tightly packed with little intercellular matrix
What is unique about the surface of epithelial tissue?
Has one free surface not in contact with other cells (except glandular epithelium)
How is epithelial tissue attached to underlying connective tissue?
By a basement membrane, a mixture of proteins and carbohydrates
What is the typical vascularity of epithelial tissue?
Typically avascular; receives nutrients by diffusion
What happens if you scratch the skin and it doesn’t bleed?
You haven’t gone through the epidermis (epithelial tissue part of skin)
What is an exception regarding the vascularity of epithelial tissue?
Glandular epithelium is highly vascular
How quickly does epithelial tissue regenerate?
Regenerates/reproduces very quickly
What are the functions of epithelial tissue? List them.
- Protection
- Filtration
- Secretion
- Diffusion
- Absorption
- Sensory reception
- Excretion
How is epithelial tissue classified?
By the number of layers and shape of the cells at the free surface
What are the two classifications based on the number of layers in epithelial tissue?
- Simple - one layer of cells
- Stratified - more than one layer
What is pseudostratified epithelial tissue?
Looks like more than one layer but is really only one; all cells in contact with basement membrane, but not all reach the free surface
What are the shapes of cells at the free surface?
Cuboidal - cube shaped
Columnar - column shaped
What are the two major categories of glands?
Endocrine glands - secrete products (hormones) directly into the blood without a duct.
Exocrine glands - secrete products onto a body surface or into a body cavity through a duct.
What is the function of endocrine glands?
Endocrine glands make up the endocrine system and secrete hormones directly into the blood.
What is the function of exocrine glands?
Exocrine glands secrete products onto a body surface or into a body cavity through a duct.
How are exocrine glands categorized?
Exocrine glands are categorized by shape, number of ducts, and type of secretion.
What are the shapes of exocrine glands?
Tubular - gland & duct are the same diameter.
Acinar/Alveolar - distal part is sac shaped.
What are the types of ducts in exocrine glands?
Simple - duct has no branches.
Compound - duct has branches.
What are the classifications of exocrine glands by product?
Merocrine glands - product is released through the cell membrane without losing cytoplasm.
Apocrine glands - a portion of the cell is pinched off, losing some cytoplasm.
Holocrine glands - entire cell is discharged and ruptures, losing all cytoplasm.
What is loose connective tissue?
Loose connective tissue, also known as areolar tissue, has collagen and elastin fibers loosely arranged. It serves as packing material, fills spaces, and cushions.
It supports epithelial tissue, anchors blood vessels and nerves, stores lipids (adipose is a specialized type), provides routes for diffusion of materials and white blood cells.
What characterizes dense regular connective tissue?
Dense regular connective tissue is mostly collagen with very few elastin fibers that are tightly packed and parallel. It is very strong in one direction.
Examples include tendons, ligaments, fascia, and aponeuroses.
What is the difference between tendons and ligaments in terms of fiber composition?
Ligaments have a few more elastin fibers than tendons.
