human physiology 100 - cell biology

What is homeostasis?

all body systems working together to maintain a stable internal environment

What is autoregulation?

Automatic response in a cell, tissue, or organ to some environmental change

What is extrinsic regulation?

Responses controlled by nervous and endocrine systems

What are the three components required for homeostasis?

1. Receptor: receives the stimulus
2. Control centre: processes the signal and sends instructions to counteract stimulus
3. Effector: carries out instructions to get organism back to normal range

What are the functions of the plasma membrane?

Phospholipid bilayer that regulates exchange with environment. Cellular Communication and structural support

What are the three main filament types of the cytoskeleton?

1. Microtubules (tubulin) large
2. Intermediate (keratin)
3. Microfilaments (actin) small

What is a proteosome?

Proteosomes contain protein degrading enzymes called proteases which breakdown and recycle damaged or normal intracellular proteins. Proteins marked with ubiquitin are removed from the cell.

What is normal membrane potential?

- slight positive charge on outside of cell
- slight negative charge on inside of cell

What is the sodium-potassium pump?

The sodium-potassium pump moves sodium and potassium ions against large concentration gradients. It moves two potassium ions into the cell where potassium levels are high, and pumps three sodium ions out of the cell and into the intracellular fluid

~ maintains a ratio of 3 Na+/ 2 K+
- ions move down their gradients through meal channels
- for every 100K+ inside, 150Na+ outside
- Therefore, it is more positive outside and less positive (more negative) inside.

What is secondary active transport?

- important for the absorption of glucose and amino acids in digestion

- moves specific substrate down its gradient: 2 sodium ions bind, then glucose is transported into the cell followed by active transport of sodium ions out of the cell