Location: parietal layer of Bowman’s capsule, lining of blood vessels (called endothelial cells), lining of alveoli
Function: sites for fluid, metabolite or gas exchange.
Simple Cuboidal Epith are found where
Location: kidney tubules, covering of ovary, ducts of glands.
Function: protection, secretion and absorption
Simple Columnar Epith are found where
Location: stomach, small intestines, gall bladder Function: protection, secretion, absorption
Pseudostratified Columnar Epith characteristics and locations they are found
Not all cells reach the surface
Nuclei are stratified at 2 or more levels
Cells are crowded – varying shapes
All cells touch the basal lamina
Location : trachea, epididymis, bronchioles
Function : protective lining, secretion, absorption
Stratified Squamous Epith have what two subgroups and characteristics
Mucous (non- keratinized) – esophagus
Cutaneous (keratinized) - skin
Stratified Cuboidal Epith are found where
Ducts of sweat glands and large ducts of Exocrine glands
Stratified Columnar Epith
Ducts of large glands
Bladder, ureter, urethra (4-6 layers)
Transitional because it will go through changes.
Cytoplasmic extensions of cell
Microvilli are made up of what
They have a core of actin microfilaments, actin binding filaments are attached to the PM by myosin I.
The core is attached to the actin filaments of the terminal web which contains intermediate filaments and spectrin as well
What is spectrin
Spectrin anchors the terminal web to the apical plasma membrane.
What is contained in the terminal web
Very long microvilli
Microvilli and stereocilia are used for
How do cilia move
Subunit A contains a pair of dynein arms which has ATPase activity. Radial spokes project from subunit A to the central sheath.
Subunit B has Nexin, an elastic protein, connects adjacent doublets.
Immotile cilia syndrome, results from hereditary defects of dynein (absence of dynein arms). Mucociliary transport in the respiratory epithelium is not functional. In males, this syndrome results in sterility since sperms are immotile
Terminal bars have what 3 groups
1. Occluding (impermeable) junctions
2. Anchoring (adhering) junctions
3. Communicating junctions – gap junction
Tight Junction (Zonula Occludens) do what
Create an impermeable junction so much so that blood will go into the intercellular space and then through the cell, not between the junctions
Zonula occludens (tight junctions) use what proteins to bind to each other
The transmembrane proteins are called occludins & claudins
What type of pathogens can make it through the tight junctions
These act on the junctions resulting in a permeable junction
Form a continuous lateral adhesive band that encircle & hold cells together. It is located beneath zonula occludens
These are calcium dependent
Macula adherens or desmosome have what function
These help to resist shearing forces.
Caused by autoantibodies produced against desmosomal proteins (resulting in blistering of skin)
Gap Junction, nexus or communicating junctions are located in what type of cells
Epithelia, cardiac and smooth muscle cells, and neurons
Composed of connexins
Gap junctions open or close via what conditions
Low pH or increase Ca+ concentration closes the channels
The opposite opens channels.
Anchor intermediate filaments of the cytoskeleton to the basement membrane.
Anchor actin filaments of the cytoskeleton to the basement membrane.
Hemidesmosome are part of what family
Integrins found on the basal side
Endocrine glands differ from exocrine in that they
Secrete hormones directly into the vascular system, so they don’t have ducts
An example of a unicellular and multicellular exocrine systems are
Goblet cell (Uni)
Apocrine gland is
Bud their secretions off through the plasma membrane producing membrane bound vesicles in the lumen. One example is the arm pits.