Cerrar
CHAPTER 1
Feedback systems maintain homeostasis
Negative Feedback systems () effects of changes in homeostasis. Works like a household (). Reduces () or shuts off original stimulus. Negative Feedback ex: Body temp, () rate, () levels.
Positive Feedback systems. Less common than negative. They increase or () the original stimulus. Two examples are: Blood () and Baby passing through the cervix which causes contractions to ()
Homeostasis(to stay the same)- The ability to maintain a stable () despite changes in the () environment. It is critical for a normal body (). Homeostatic imbalance increase as you get older.
CHAPTER 3
Passive transport is when () ATP is required.
Diffusion(passive) (simple diffsion) Is the movements of molecules from high concentration to () concentration. (Down the concentration () ) Speed in influenced by temp and particle size. Higher temp = () diffusion. Smaller particles = () diffusion. Examples: Oxygen and CO ().
Facilitated Diffusion(passive) is the same thing but the molecules need carrier proteins or () proteins. Particles are either too large to pass through the ()- layer or they are charged and repelled. The rate of diffusion is limited by number of carries/(). () Channels are channels that are open all the time. Channels that are controlled by chemical signals are () channels.
Osmosis(passive)- Diffusion of water through a selectivly preamble membrane. Water moves very () through lipid bi-layers. The water concentration is determined by () concentration. Water () and () the cell during osmosis. Changes in volume disrupt cell ()
Tonicity is the ability of a solution to cause a cell to shrink or ().
Isotonic Solution: Solution with () solute concentration as cytoplasm. Cells in this concentration maintain the same (). Human extracellular fluid is isotonic.
Hypertonic Solution
- Solution with greater solute
concentration than cytoplasm
- Cells in these solutions lose
()& shrink ()
- Dehydration leads
()
- Solution with lower solute
concentration than cytoplasm
- Cells in these solutions gain
() & can burst (“)
Active transport is when ATP is required. They need special carrier ().
Vesicular transport
- Requires ATP
- Cell uses () (hollow capsules) to move large substances in/out
- Also called “()” transport
Endocytosis:
bulk transport of substances () the cell
2 Types:
1) ()
- Using pseudopods to engulf solids
- “Eating”
- Macrophages, white blood cells
2) Pinocytosis
- Membrane infolds, bringing in
extracellular fluid
- “drinking”
- () absorption in small intest.
Exocytosis:
bulk transport of substances OUT of the cell
Examples:
1) Hormone()
2) Neurotransmitter release
3) Mucus secretion
