Star points test #1 Flashcards
definition of tissues
group of cells of similar structure that perform a common function.
four basic types of tissues
epiethelium, connective, muscle, nervous
functions of epithelial tissue
lining of surfaces
functions of connective tissues
- connecting tissues and organs
- form the basis of the skeleton,
- store and carry nutrients,
- surround all the blood vessels and nerves,
- lead the immune system.
function of muscle tissue
movement
functions of nervous tissue
communication
tight junctions
-form the closest contact between adjacent cells known in nature.
-so tight that some proteins in the plasma membrane are fused.
-Found in the apical region around the cell’s circumference, like a belt.
-these prevent molecules from passing.
(plays a role in secondary immune response because antigens ‘tighten’ the cell junction.)
desmosomes
- localized adhesive function and connect the plasma membrane to intermediate filaments in the cytoplasm.
- the connections are especially important in stratified epithelium as it helps form an internal tension-reducing networks of fibers.
gap junction
- consist of intercellular channels in the plasma membrane of adjacent cells.
- Small molecules can diffuse across the channel and into the cytoplasm of the other cell.
- “communicating junction” allows passage.
cell size is what size and what determines it?
- normally 5-20 micrometers
* limited by reliance on diffusion
definition of epithelium
Tissue that covers or lines surfaces and cavities of the body
or
(2) forms glands/ secretory structures
general characteristics of epithelium (7)
- Cellularity:
- Make specialized contacts
- Display polarity - apical, basal (e.g. goblet cell - secretes mucus)
- Basement membrane (anchors epithelium to the underlying connective tissue)
- Ability to regenerate quickly
- Avascular = no blood vessels • Innervated
functions of epithelium
• Absorption and Secretion (active transport)
-microvilla and cilia
• Diffusion and Filtration (passive transport)
• Sliding
• Protection
• Sensory reception

how do we classify epithelium?
by layering: simple vs stratified
by shape: squamous, cuboidal, columnar.
definition of a gland
structure whose cells are specialized for secretion
exocrine
type of gland that secretes products onto body body surfaces or into body cavities,
- contains ducts that carry these protiens to the surface (except the single celled goblet cells)
endocrine
glands that secretes hormones into the blood.
properties of reticular fibers
1] composed of type III collagen secreted by reticular cells.
[2] Reticular fibers crosslink to form a fine meshwork (reticulin). This network acts as a supporting mesh in soft tissues such as
-liver,
-bone marrow,
-tissues and organs of the lymphatic system.
-used at boundaries of tissues.
[3] Forms delicate networks with lots of spaces • Allows smooth gliding / deformation
areolar connective tissue
most widespread, ‘generic’, gel like matrix, lots of fluid, ADJOINS ALL EPITHELIAL, is a loose connective tissue
goblet cell
unicellular exocrine gland that is shaped as a goblet, secrets mucin that dissolves when secreated to form mucus
basal lamina
thin noncellular sheet that consists of proteins secreted by epithelial cells.
basement membrane
consists of the basal lamina and reticular fibers of the underlying connective tissue.
microvilla
almost every moist epithelia. but most abundant in small intestine (absorbs nutrients) and transport ions (kidneys).
cillia
- whiplike centoles projection from the apical surface of certain epithelial cells
- wavelike movement moves mucous (or reproductive cells) over the area in one direction only.