What are tissues?
groups of similar cells similar in structure and function
What are the four types of tissues?
- 1. Epithelial - covering
- 2. Connective - support & binding
- 3. Muscle - movement
- 4. Nerve - control
What are the characteristics of Epithelial Tissue?
- - supported by connective tissue (called basement membrane)
- - avascular (no blood supply) but innervated (has nerves)
- - regenerative
- - polarity (definite shape)
- - simple (single) & stratified (multiple) layers
- - cell shape
What are the 3 cell shapes?
squamous, cuboidal, and columnar
- diffusion and filtration, friction reducing lining
- - found in lining of heart and blood vessels
- - epithelial type of tissue
- secretion and absorption
- - found in kidney tubules and ovary surface
- absorption and secretion
- - ciliated cells found in ining of bronchi, uterine tubes
- - conciliated found in digestive tract, gallbladder
- single layer of cells with different heights; some do not reath the free surface
- - function in secretion and propulsion of mucus
- - present in the sale sperm-carrying ducts (conciliated) and trachea (ciliated)
- protection of underlying areas subjucted to abrasion
- - found in the external skin's epidermis and lining of the esophagus, mouth and vagina
- - quite rare in the body
- - found in some sweat and mammary glands
- - limited distribution in the body
- - found in the pharynx, male urethra, and lining some glandular ducts
- - several cell layers, basal cells are cuboidal, surface cells are dome shaped
- - stretches and changes shape
- - lines the urinary bladder, ureters, and part of the urethra
a gland is one or more cells that make and secrete an aqueous fluid
Epithelia: Glandular; how are they classified?
- - site of product release - endocrine or exocrine
- - relative number of cells forming the gland - unicellular or multicellular
What are the two types of glands?
endocrine & exocrine
What are endocrine glands?
- ductless glands that produce hormones
- - enter the blood and stay in the blood
What are 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
Modes of Secretion (Exocrine)
- - merocrine: products are secreted by exocytose (e.g. pancreas, sweat, and salivary glands)
- - holocrine: products are secreted by the rupture of gland cells (cells destroyed in process)
- found throughout the body; most abundant and widely distributed
- - fills the spaces in the body between the other major tissue types (connective tissue proper, cartilage, bone, blood)
Functions of Connective Tissue
- - binding and support
- - protection
- - insulation
- - transportation (blood deals mostly with transportation)
Structural Elements of Tissue
- - gound substance - unstructured material that fills the space between cells
- - fibers
- - cells
- - interstitial (tissue) fluid (mostly water)
- - adhesion proteins - fibernectin and laminin
- - proteoglycans - glycosaminoglycans (GAGs)
How do proteoglycans - glycosaminoglycans (GAGs) function?
function as a molecular sieve through which nutrients diffuse between blood capillaries and cells
What are the three types of functions? Describe each.
- - collagen: tough; provides high tensile strength
- - elastic: long, thin fibers that allow for stretch
- - reticular: branched collagenous fibers that form delicate networks
List the 4 different types of cells
- - fibroblasts: connective tissue proper
- - chondroblasts: cartilage
- - osteoblasts: bone
- - hematopoietic stem cells: blood (white blood cells, plasma cells, macrophages and mast cells)