unit 8

Question 1

three important conditions that must be met for chemical reactions in the body for homeostasis

Answer 1

1. proper concentration of gases, nutrients, water and salts.
2. optimal temp
3. optimal pressure

Question 2

intracellular fluid?

Answer 2

also called cytoplasm (cytosol and the fluid inside organelles). Intracellular fluid makes up approximately 2/3 of the total body fluids.

Question 3

extracellular fluid

Answer 3

The internal environment is thus equivalent to the extracellular fluid. Extracellular fluid is found in blood (i.e. plasma), in tissues (i.e. interstitial fluid), in the lymphatic system (i.e. lymph), in joints (i.e. synovial fluid), in the eyes (i.e. aqueous and vitreous humors) and in the central nervous system (i.e cerebrospinal fluid). Extracellular fluid amounts to about 1/3 of the fluids in the body as a whole.

Question 4

main fluid types of extracellular fluid

Answer 4

plasma. interstitial fluid, lymph

Question 5

what is plasma?

Answer 5

is the liquid portion of blood and functions to move red and white blood cells, platelets, nutrient molecules, gases, electrolytes and wastes throughout the circulatory system. Materials are exchanged at capillary beds where the blood vessel walls are thin enough to allow materials to move between the blood and the tissues.

Question 6

fluid surrounding cells in tissues is….

Answer 6

interstitial fluid
- components of plasma move into tissues, thus interstitial fluid is partly derived from plasma
-also in contact with cells and partly derived from intracellular fluid

Question 7

why is interstitial fluid returned to circulatory system?

Answer 7

• maintain appropriate pressure within cardiovascular system
• waste materials from cell to be removed

Question 8

interstitial fluid pressure

Answer 8

Interstitial fluid has lower pressure than plasma in capillaries, so 85% of it is returned directly to the circulatory system via osmotic gradient

Question 9

what returns to lymphatic system

Answer 9

The remaining 15% of interstitial fluid is returned indirectly through the lymphatic system.

Question 10

lymphatic drainage

Answer 10

Lymph is collected into larger lymphatic vessels and eventually drains into veins near the heart.

Question 11

what is a stressor?

Answer 11

• any stimulus that causes an imbalance in internal environment
• external: lack of O2, extreme temps
• internal: nutrients, glucose levels etc.

Question 12

negative feedback loop

Answer 12

stimulus > sensor> control > effector > back to stimulus

Question 13

example of negative feedback loop

Answer 13

• the way the body cools ***

Question 14

examples of positive feedback loops

Answer 14

childbirth **