Cell and Molecular Physiology Flashcards
maintenance of nearly constant conditions in the internal environment compatible with life
Homeostasis
Total Body Weight
60% of body weight
Intracellular Fluid (ICF)
40% of body weight
Extracellular Fluid (ECF)
20% of body weight
also called the internal environment of the body, or the milieu intérieur
Extracellular Fluid
- large amounts of sodium, chloride, and bicarbonate ions
* nutrients for the cells, such as oxygen, glucose, fatty acids, and amino acids
Extracellular Fluid
- large amounts of potassium, magnesium, and phosphate ions
- special mechanisms for transporting ions through the cell membranes maintain the ion concentration differences between ECF and ICF
Intracellular Fluid
considered to be a state of disrupted homeostasis
Disease
Fast; neurons; electrical impulse; external environment; for nervous coordination
Nervous Control
Slow; hormones; organic message; internal environment; for chemical coordination
Hormonal Control
Is separated from the cytoplasm by a nuclear membrane
Nucleus
separated from the surrounding fluids by a cell membrane or plasma membrane
Cytoplasm
collective term for different substances that make up the cell
Protoplasm
Five basic substances of Protoplasm
O Water O Electrolytes O Proteins O Lipids O Carbohydrates
25% of Extracellular Fluid (ECF)
Plasma
75% of Extracellular Fluid
Interstitial Fluid
- principal fluid medium of the cell
* present in most cells, except for fat cells, in a concentration of 70-85 percent
Water
- inorganic chemicals for cellular reactions
* necessary for operation of some of the cellular control mechanisms
Electrolytes / Ions
• constitute 10 to 20 percent of the cell mass
Protein
Proteins can be divided into
O Structural Proteins
O Functional Proteins
• long intracellular filaments that form microtubules and fibrillar proteins
EXAMPLES
- cytoskeleton of cellular organelles
- fibrillar proteins in collagen and elastin fibers
Structural Proteins
Composed of combinations of a few molecules in tubular-globular form
EXAMPLES:
- Enzymes
Functional Proteins
Substances that catalyze specific intracellular chemical reactions
Enzymes
How fast can enzyme speed up chemical reactions?
10^6
Soluble in fat solvents but insoluble in water; Eg. Phospholipids and Cholesterol, Triglycerides
Lipids
- 2% of total cell mass
- forms the cell membrane and membrane barriers
Phospholipids and Cholesterol
- in fat cells, constitutes 95% of the cell mass
- storehouse of energy-giving nutrients
- also called as neural fat
Triglycerides
- little structural function in the cell except as parts of glycoprotein molecule
- play a major role in cellular nutrition
Carbohydrates
- also called plasma membrane
- thin, pliable, elastic structure (7.5 to 10 nm)
- its basic structure is a lipid bilayer
Cell Membrane
Most abundant of the cell membrane lipids
Phospholipids