Papillary muscles:
a) prevent the av valve leaflets bulging too far into the aorta during ventricular systole.
b) are a type of smooth muscle.
c) are smooth muscle extensions of the walls of the ventricles.
d) assist the opening of closure of the semi-lunar valves.
e) upon contraction, pull on the chordae tendinae holding the av valve leaflets closed.

The arrows in the illustration point to

18. determine whether each stateme blank space given. ach statement is true (t) or false (f). place your answer in the 8. when a cell is put into an isotonic solution, individual wat put into an isotonic solution, individual water molecules cannot move back and forth across the cell membrane. d. when a cell is put into a hypertonic solution, there is a net movement of water molecules across the cell membrane into the cell. c. when a cell is put into a hypotonic solution, there is a net movement of water molecules across the cell membrane out of the cell. d. the movement of any solvent across a semi-permeable membrane is called osmosis. e. carrier proteins have the ability to change shape and physically move molecules across the cell membrane. f. in facilitated diffusion, the concentration of the molecules to be moved across the cell membrane is higher inside the cell.

What is the name of the protein found in erythrocytes that transports respiratory gases and provides the red color?