Chapter 1 and 2 (Physiology)
Termini in questo insieme (27)
Physiology is the study of the normal functions of organisms, including plant, cell, microbial, and human physiology.
Pathophysiology studies what happens when normal physiological functions go wrong.
Emergent properties arise from complex interactions of many components, such as cells and macromolecules, producing new functions.
Teleological approach explains the why or adaptive significance; mechanistic approach explains the how or processes behind physiological events.
Homeostasis is the maintenance of a stable internal environment by organ systems despite external changes.
Variables include temperature, pH, volume, pressure, and osmolarity.
Excitable cells are cells that can generate electrical signals, such as neurons and muscle cells.
The cell membrane separates the intracellular fluid inside cells from the extracellular fluid outside cells.
ICF: High K+, low Na+, low Cl-. ECF: High Na+, high Cl-, very low K+.
The body exchanges matter with the environment; maintaining homeostasis requires mass balance where intake equals output.
Mass balance = (Existing body load + Intake or metabolic production) - (Excretion or metabolic removal).
Intake: Food, drink, gases, lipids. Output: Urine, feces, lungs, skin.
Clearance is the rate at which a substance is removed from the blood, measured as volume of blood cleared per unit time.
Clearance occurs mainly in the skin, kidneys, and liver.
1. Input signal, 2. Integrating center, 3. Output signal that creates a response.
Negative feedback opposes the initial change to maintain homeostasis, e.g., lowering high blood pressure.
Positive feedback amplifies the initial change and requires an outside stop, e.g., childbirth contractions and blood clotting.
Feedforward control initiates a response in anticipation of a change before it occurs.
Biological rhythms are predictable changes in setpoints of regulated variables, such as circadian rhythms affecting body temperature and hormone levels.
Acclimatization is the adjustment of an organism's traits to match a new environment.
Specificity is a protein's ability to bind a particular ligand; affinity is the strength of this binding based on shape and conformation.
The reaction direction depends on relative concentrations of reactants and products; high equilibrium constant favors products, low favors reactants.
Isoforms are closely related proteins with similar functions but different ligand affinities, e.g., fetal hemoglobin has higher oxygen affinity.
Proteins are synthesized inactive and become active when peptide fragments are removed, e.g., trypsinogen to trypsin.
Modulators can change a protein's ability to bind ligands or create a response, acting as inhibitors or activators at main or allosteric sites.
Saturation occurs when all protein binding sites are occupied, limiting further response despite increased ligand concentration.
Up-regulation is increased protein production; down-regulation is programmed removal of proteins, affecting cell responsiveness.