Chapter 3, Lesson 2: The Cell Surface

Flashcards from Chapter 3, Lesson 2 of McGraw Hill Anatomy and Physiology, Ninth Edition, by Kenneth S. Saladin.

Plasma membrane

The border of the cell; has intracellular and extracellular faces to define cell boundaries and interact with other cells and materials

Phospholipids

Makes up 75% of the membrane lipids; arranged in a bilayer of hydrophilic phosphates and hydrophobic tails

Cholesterol

Makes up 20% of the membrane lipids, holds phospholipids and can stiffen membrane

Glycolipids

Makes up 5% of the membrane lipids, are phospholipids with short carbohydrate chains on the extracellular face

Integral proteins

Proteins that penetrate the membrane; hydrophilic regions contact the cytoplasm, while hydrophilic regions contact the lipids

Peripheral proteins

Proteins that adhere to one face of the membrane and are tethered to the cytoskeleton

Receptors

Protein that binds to chemical messengers such as hormones sent by other cells

Enzyme

Protein that breaks down a chemical messenger and terminates its effect

Channel

Protein that is constantly open and allows solutes to pass in and out of the cell

Gated channel

Protein that opens and closes to allow solutes to pass through at certain times

Cell-identity marker

A glycoprotein distinguishing the body’s own cells from foreign cells

Cell-adhesion molecule

A molecule that binds one cell to another

Second messenger systems

Systems within a cell that communicate with receptors to send messages internally

Glycocalyx

A fuzzy coat external to the membrane made up of glycoproteins and glycolipids

Microvilli

Extensions of the membrane developed in cells specialized in absorption (stomach cells)

Cilia

Hair-like processes 7 to 10 um long, found on nearly every cell for monitoring nearby conditions

Nonmotile cilia

Found on sensory cells of the nose

Motile cilia

Found in the respiratory tract and ventricles of the brain, beats in waves sweeping materials in one direction

Chloride pumps

Pumps Cl^- into extracellular fluid alongside Na⁺ and H₂O so mucus can flow; these being broken result in cystic fibrosis (mucus buildups)

Flagella

Whip-like structure identical to cilium’s with undulating movement; sperm is the only functional one in humans

Pseudopods

Continually changing extensions of the cell that vary in shape and size; used for locomotion and foreign particle capture