E109 Physiology

ephithielium

barrier between cellular lumen (environment) and cell interior

blood

least rigid connective tissue, composed of WBCs, RBCs, cell fragments (platelets), and liquid matrix (plasma)

adipose tissue

Cushions and insulates, stores energy. Two types: ground fat (plays a role in thermodynamic insulation) and white fat.

Loose connective tissue

surrounds blood vessels and internal organs

cartilage

elastic tissue, absorbs shock 

dense connective tissue

regular: tendons (connects muscle to bone) and ligaments (connects bone to bone)

irregular: muscle and nerve sheaths

bone

most rigid connective tissue, structural support, organ protection, force transmission (without it, the muscles in the arm wouldn’t be enough to bend the arm)

Exchange epithelia

Found in lungs, lining of blood vessels; helps with exchange of materials; also called leaky epithelia

Transport epithelia

found in intestine, kidney, some exocrine glands; specialized for absorption and controlled transport of substances; more selective than exchange epithelia

Ciliated epithelia

found in nose, trachea, upper airways and female reproductive tract

Protective epithelia

found in skin and lining of cavities open to environment. In skin, cells are anchored to basal lamina by hemidesmosomes. 

Secretory epithelia

found in cells that secrete chemicals such as mucus and hormones (think goblet cells) 

Na+ K+ ATPase

primary active transport: uses ATP to move Na+ and K+ against concentration gradients

Na+ glucose symporter

secondary active transport: uses Na+ gradient to transport glucose, carrier protein

GLUT transporter

facilitated diffusion: transports glucose via facilitated diffusion

Nernst equation

concentration difference and charge of ions determine equilibrium potential

Goldman-Hodgkin-Katz equation

Permeability dictates how close the membrane potential is to the equilibrium potential of an ion

polarization

resting potential of an excitable cell, where the inside of the cell is negative compared to the outside

depolarization

difference in membrane potential is reduced, so the inside of the cell becomes more positive than prior

myofibril

embedded in muscle fibers which are embedded in muscle fascicles, sarcomeres are in series along myofibrils