Tissue Fluid (AQA A-Level Biology): Flashcards

Definition of tissue fluid

Watery solution that surrounds and bathes all cells in the body

What are the main components found in tissue fluid?

Glucose, amino acids, fatty acids, dissolved ions, oxygen

Process where hydrostatic pressure forces molecules out of blood

Ultrafiltration

Where is hydrostatic pressure highest in capillaries?

Arterial end (where blood first arrives from heart)

What can pass through capillary walls during ultrafiltration?

Small molecules: water, glucose, amino acids, ions

What cannot pass through capillary walls?

Blood cells and large proteins

Two forces opposing fluid movement out of capillaries

1. Hydrostatic pressure of tissue fluid outside 2) Osmotic pressure from plasma proteins (lower water potential in blood)

Pressure inside capillaries at venous end vs tissue fluid

Lower than tissue fluid pressure outside

System that collects excess tissue fluid

Lymphatic system

Three mechanisms that move lymph toward the heart

Hydrostatic pressure, muscle contractions, one-way valves