Human Anatomy and Physiology: Chapter 3 - Cells: The Living Units

This flashcard set covers the fundamental concepts of cell biology from Chapter 3, including cell structure, the plasma membrane, cell junctions, transport mechanisms, and tonicity.

Cell

The structural and functional unit of life.

Plasma membrane

The flexible outer boundary of a cell that acts as an active barrier separating intracellular fluid (ICF) from extracellular fluid (ECF).

Cytoplasm

Intracellular fluid containing organelles.

Nucleus

The DNA-containing control center of a cell.

Interstitial fluid

Extracellular fluid in which cells are submersed or bathed.

Blood plasma

The fluid component of the blood.

Cerebrospinal fluid

The fluid surrounding the nervous system organs.

Extracellular matrix

Substance that acts as glue to hold cells together.

Fluid mosaic

A pattern of the plasma membrane where specialized proteins float through a flexible lipid bilayer, resulting in constantly changing patterns.

Glycocalyx

A "sugar coating" of carbohydrates sticking out of the cell surface that functions as biological markers for cell-to-cell recognition.

Tight junctions

Impermeable junctions that form continuous seals around the cell to prevent molecules from passing between cells.

Desmosomes

Cell junctions that counteract physical stress; they are prevalent in areas like cardiac muscle tissue.

Gap junctions

Communicating junctions that allow ions and small molecules to pass from cell to cell through channels formed by connexons.

Passive transport

Movement of substances across the plasma membrane where no energy (ATP) is required.

Active transport

Movement of substances across the plasma membrane that requires energy (ATP).

Tonicity

The ability of a solution to change the shape or tone of cells by altering the cells' internal water volume.

Isotonic solution

A solution with the same osmolarity as inside the cell, resulting in no change in cell volume.

Hypertonic solution

A solution with a higher osmolarity than inside the cell, causing water to flow out and the cell to shrink.

Crenation

The shrinking of a cell, which occurs when it is placed in a hypertonic solution.

Hypotonic solution

A solution with a lower osmolarity than inside the cell, causing water to flow in and the cell to swell.

Lysing

The bursting of a cell, which can occur in a hypotonic solution.

Sodium-potassium pump ($Na^+-K^+$ ATPase)

An enzyme that actively pumps $Na^+$ out of the cell and $K^+$ back into the cell.

Endocytosis

Vesicular transport of large particles, macromolecules, and fluids across the membrane into the cell.

Phagocytosis

A type of endocytosis referred to as "cell eating," involving the engulfing of solid material.

Pinocytosis

A type of endocytosis referred to as "cell drinking," involving the engulfing of fluid material.