unit 2 Flashcards
(17 cards)
What is the biological importance of water as a lubricant and cushion?
Water acts as a lubricant in synovial and pleural fluids, protects organs from trauma, and cushions the brain and developing fetus.
Examples include lubrication of joints and cushioning of the brain within the skull.
What role does water play as a heat sink in the human body?
Water absorbs heat generated by chemical reactions without greatly increasing in temperature, helping to cool the body through evaporation.
Evaporation of sweat cools the blood near the skin’s surface.
How does water function as a component of liquid mixtures?
Water acts as a solvent in solutions, keeping cells moist and allowing for even distribution of solutes throughout the liquid.
An example is sugar dissolving in water.
What are the two types of chemical reactions involving water?
Dehydration synthesis and hydrolysis.
Dehydration synthesis releases water, while hydrolysis uses water to break bonds.
What percentage of body weight is composed of water in adults?
Approximately 50% in women and 60% in men.
Percentages vary with age and body composition.
What is intracellular fluid (ICF)?
Fluid enclosed within cells by their plasma membranes, making up about 55% of total body water.
ICF accounts for roughly 20 litres in an average adult.
What is extracellular fluid (ECF)?
Fluid that surrounds all cells in the body, including plasma and interstitial fluid.
ECF accounts for the remainder of the body’s water content.
What is the primary component of plasma?
The fluid component of blood that transports cells, proteins, electrolytes, nutrients, gases, and wastes.
Plasma makes up about 16% of the extracellular fluid.
What is interstitial fluid (IF)?
Fluid that surrounds living cells in tissues, accounting for nearly 80% of extracellular fluid.
It facilitates the exchange of materials between capillaries and cells.
Fill in the blank: The intracellular fluid makes up about _______ of the total water in the human body.
55%.
True or False: The water content of the body varies significantly among different organs and tissues.
True.
Water content ranges from 8% in teeth to 85% in the brain.
List some types of extracellular fluid.
- Cerebrospinal fluid
- Lymph
- Synovial fluid
- Pleural fluid
- Pericardial fluid
- Peritoneal fluid
- Aqueous humor of the eye.
What happens to cells if the amount of water inside them becomes too low?
The cytosol becomes too concentrated with solutes, impairing normal cellular activities.
What is a heat sink?
A substance that absorbs and dissipates heat without a corresponding increase in temperature.
What percentage of body weight can water comprise in infants?
About 75%.
What is dehydration synthesis?
A reaction where one reactant gives up an atom of hydrogen and another gives up a hydroxyl group, releasing water as a byproduct.
What is hydrolysis?
A reaction where a molecule of water disrupts a compound, breaking its bonds.
