Body Fluids & Homeostasis - ME

What is homeostasis?

Maintenance of a stable internal environment within the body, crucial for optimal cellular function.

What percentage of the human body is made up of fluids?

Approximately 70% of body weight.

What are the two main fluid compartments in the body?

Intracellular fluid (ICF) and extracellular fluid (ECF).

Where is intracellular fluid located?

Inside the cells, making up about 55% of total body water.

Where is extracellular fluid located?

Outside the cells, accounting for about 45% of total body water.

What are the components of extracellular fluid?

Interstitial fluid, plasma, and lymph.

What is interstitial fluid?

Fluid located between cells; about 80% of extracellular fluid.

What functions does interstitial fluid serve?

Delivers nutrients, facilitates communication, and removes waste.

What is plasma?

Fluid portion of blood that transports oxygen, carbon dioxide, and nutrients.

What is lymph?

A clear fluid (~96% water) containing proteins, lipids, carbohydrates, and electrolytes.

What other fluids are included in lymph?

Synovial fluid, cerebrospinal fluid, and pleural/pericardial/peritoneal fluids.

What is water balance?

When water intake equals water output.

Where does most daily water intake come from?

60% from drinking, 30% from moist food, 10% from metabolic water.

What regulates water intake?

The thirst mechanism, influenced by osmotic pressure and hypothalamus signals.

How is thirst inhibited?

By stomach distention after drinking.

How is water lost from the body?

Urine, feces, perspiration, insensible skin loss, and breathing.

What affects the rate of water loss?

Temperature, humidity, and physical activity.

What are electrolytes?

Charged ions found in all body fluids.

Why is electrolyte balance important?

To maintain fluid balance, acid-base regulation, enzyme reactions, and neuromuscular function.

How is electrolyte intake usually achieved?

Through food consumption.

What can salt cravings indicate?

Possible electrolyte deficiency.

How are electrolytes lost?

Sweat, urine, and feces.

What is the role of feedback mechanisms in homeostasis?

To maintain internal stability by responding to changes.

What is negative feedback?

A mechanism that counteracts changes to maintain stability.

What are the components of negative feedback?

Stimulus, sensor/receptor, control center, and effector.

What is positive feedback?

A mechanism that amplifies changes, useful in specific cases like childbirth.

What are the main components of the lymphatic system?

Lymph, lymphocytes, lymph vessels, lymph nodes, thymus, spleen, tonsils, adenoids, and bone marrow.

What are lymphocytes?

White blood cells essential for immune response (B and T cells).

What are lymph vessels?

Vessels that transport lymph throughout the body.

What are lymph capillaries?

Small vessels that absorb interstitial fluid.

What do lymphatic trunks do?

Drain lymph from different body regions.

What do lymphatic ducts do?

Drain lymph into subclavian veins to return to bloodstream.

What do lymph nodes do?

Filter lymph, remove pathogens and waste, and house immune cells.

What is the function of the thymus?

Promotes development of T-lymphocytes for cell-mediated immunity.

What hormones does the thymus produce?

Hormones that aid T-lymphocyte growth and maturation.

What is the spleen’s function?

Filters blood, removes pathogens and damaged cells, and transports lymph to nodes.

What do tonsils and adenoids do?

Protect against pathogens entering through mouth and nose.

What is the function of bone marrow?

Produces blood cells and lymphocytes.

What are the three major functions of the lymphatic system?

Immune defense, fluid homeostasis, and fat absorption.