Chapter 4 - The Tissue Flashcards
Epithelia: Simple Squamous
- Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm
- Functions
- Diffusion and filtration
- Provide a slick, friction-reducing lining in lymphatic and cardiovascular systems
- Present in the kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae
Epithelia: Simple Cuboidal
Single layer of cube-like cells with large, spherical central nuclei
Function in secretion and absorption
Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface
Epithelia: Simple Columnar
- Single layer of tall cells with oval nuclei; many contain cilia
- Goblet cells are often found in this layer
- Function in absorption and secretion
- Non-ciliated type line digestive tract and gallbladder
- Ciliated type line small bronchi, uterine tubes, and some regions of the uterus
- Cilia help move substances through internal passageways
Pseudostratified Columnar
- Single layer of cells with different heights; some do not reach the free surface
- Nuclei are seen at different layers
- Function in secretion and propulsion of mucus
- Present in the: male sperm-carrying ducts (non-ciliated) and trachea (ciliated)
Epithelia: Stratified Squamous
- Thick membrane composed of several layers of cells
- Function in protection of underlying areas subjected to abrasion
- Forms the external part of the skin’s epidermis (keratinized cells), and linings of the esophagus, mouth, and vagina (non-keratinized cells)
Epithelia: Stratified Cuboidal and Columnar
- Stratified cuboidal
- Quite rare in the body
- Found in some sweat and mammary glands
- Typically two cell layers thick
- Stratified columnar
- Limited distribution in the body
- Found in the pharynx, male urethra, and lining some glandular ducts
- Also occurs at transition areas between two other types of epithelia
Epithelia: Transitional – one location
- Several cell layers, basal cells are cuboidal, surface cells are dome shaped
- Stretches to permit the distension of the urinary bladder
- Lines the urinary bladder, ureters, and part of the urethra
Epithelia: Glandular
- A gland is one or more cells that makes and secretes an aqueous fluid, ie, sweat glands
- Classified by:
- Site of product release – endocrine or exocrine
- Relative number of cells forming the gland – unicellular or multicellular
Endocrine Glands
- Ductless glands that produce hormones
- Secretions include amino acids, proteins, glyco-proteins, and steroids
- Secrete product outside the cells and let the blood, insterstitial fluid, etc. pick it up.
Exocrine Glands
- More numerous than endocrine glands
- Secrete their products onto body surfaces (skin) or into body cavities
- Examples include mucous, sweat, oil, and salivary glands
- The only important unicellular gland is the goblet cell
- Multicellular exocrine glands are composed of a duct and secretory unit
Merocrine
products are secreted by exocytosis (e.g., pancreas, sweat, and salivary glands)
Holocrine
products are secreted by the rupture of gland cells (e.g., sebaceous glands) (holocrine = the hole thing breaks)
Connective Tissue
- Found throughout the body; most abundant and widely distributed in primary tissues
- Connective tissue proper
- Cartilage
- Bone (osseous)
- Blood (yes, blood is a connective tissue and this makes a really cool test question ‘cause it’s not intuitive)
Functions of Connective Tissue
- Binding and support
- Protection
- Insulation
- Transportation (RBC’s)
Fibroblasts
connective tissue proper
