Ch. 3 - microvilli, cilia & flagella

cilia

- 7-10 micrometers long

basal body

- anchors the cilium

microvilli

- best developed in cells specialized for absorption - gives 15 to 40 times more surface area

pseudopods

- cytoplasm filled extensions of the cell varying in shape - continually changing

ciliopathies

- defects in structure & function of cilia, especially nonmotile primary cilia

microvilli

- extensions of plasma membrane - serve primarily to increase cell's surface area

multiple nonmotile cilia

- found on sensory cells of nose

cilia

- hairlike processes

cilia

- helps w/ balance in inner ear, light detection in retina

cystic fibrosis

- hereditary disease when cells make chloride pumps, but fail to install them in the plasma membrane - thick mucus plugs pancreatic ducts and respiratory tract

motile cilia

- less widespread - occuring in respiratory tract, uterine tubes, internal cavities of the brain, short ducts - 50 to 200 on each cell - beat in waves - mucus & egg cell

cilia

- many are sensory, serve as the cell's antenna for monitoring nearby conditions

flagella

- movement is undulating, snake like corkscrew

flagella

- much longer than cilium & has identical axoneme

cilia

- nearly every human cell has a single nonmotile primary cilium

microvilli

- only 1-2 micrometers - can't be distinguished very well w/ light microscope

flagella

- only one functional in humans

microvilli

- show little internal structure, some have bundle of stiff filaments of protein called actin - actin filaments get tugged by another protein toward center if the cell to milk absorbed contents into cell

microvilli

- some are very dense & appear as a fringe called the brush border

flagella

- stiffened by coarse fibers that support the tail

axoneme

- structural basis for ciliary movement core, consists of microtubules

flagella

- whip like tail of a sperm