Module 2: Histology: The Study of Tissues Flashcards
Epithelial tissue
Makes up the linings of organs, the outer layer of skin, the linings of the mouth and stomach, the thyroid gland, pancreas, liver, and forms glands.
Connective tissue
Supports, binds, and insulates. Examples include bone, cartilage, tendons, and fat.
Nervous tissue
Sends and receives signals. It makes up the brain, spinal cord, and nerves.
Muscle tissue
Allows for movement.
Free surface
The top surface of epithelial tissue.
Basal surface
The bottom surface of epithelial tissue.
Basement membrane
The glue secreted by epithelial cells that attach the basal surface to underlying tissue.
Avascular
Lacking blood vessels
Vascular
Refers to blood vessels
How do epithelial tissues receive nutrients?
The blood vessels in the underlying tissue release oxygen and nutrients which diffuse across the basement membrane into the cells.
What two characteristics classify epithelial linings?
The number of layers and the shape of the cells that make up those layers.
Simple epithelium
A one-layered epithelial lining.
Stratified epithelium
A multilayered epithelial lining.
Squamous epithelium
Flat epithelial cells.
Cuboidal epithelium
Epithelial cells shaped like a cube.
Columnar epithelium
Epithelial cells shaped like a column.
What is the function of simple squamous epithelium?
They offer a minimal barrier through which diffusion of oxygen and nutrients can occur. They are too simple for complex tasks and do not have many organelles.
What is the function of simple cuboidal epithelium?
Diffusion, absorption, and secretion. They have organelles such as rough ER and Golgi apparatuses.
What is the function of simple columnar epithelium?
Performs complex secretion and absorption tasks.
Goblet cells
Cells whose main job is to produce mucus.
Mucus
A complex mixture of fluids, proteins, and carbohydrates that covers, protects, and lubricates a free surface within the body.
Where is stratified squamous epithelium located?
The skin.
Epidermis
The top layer of skin made up of epithelial tissue that forms a barrier.
How is skin made?
The basal cells in skin divide by the process of mitosis, and they push up on the cells on top of them. When the cells reach the surface, they are dead and flake off.
Keratin
The water-proofing protein found in dead skin cells.
Moist stratified squamous epithelium
A type of epithelial tissue whose surface cells are covered with mucus and is nonkeratinized.
Where is stratified cuboidal epithelium found?
The parts of the salivary glands that secrete saliva into the mouth.
Where is stratified columnar epithelium found?
The larynx.
What are the characteristics of stratified transitional epithelium?
Multilayered, provides protection, and is able to stretch.
Where is stratified transitional epithelium found?
The bladder because it can stretch.
Pseudostratified epithelium
“Falsely layered” epithelial tissue. Some of the cells are shorter than the others and cannot reach the basement membrane. It has goblet cells and cilia.
Where is pseudostratified epithelium?
The nasal passages, the air sinuses of the skull, and the large airways of the lungs.
Exocrine glands
Glands that secrete substances outward through a duct.
Endocrine glands
Ductless glands that secrete hormones into the bloodstream.
Secretory portion (exocrine glands)
The part of an exocrine gland that contains the cells that do the secreting.
Duct (exocrine glands)
The part of exocrine glands through which the chemicals travel to reach the surface.
Merocrine glands
Exocrine glands that secrete without losing cellular material.
Example: Sweat glands
Apocrine glands
Exocrine glands that have cytoplasm in their secretions.
Example: Mammary glands.
Holocrine glands
Exocrine glands that have secretions made up of disintegrated cells.
Example: Sebaceous glands on the skin that secrete oil.