BASIC HUMAN PHYS QUIZ 1

A comprehensive set of vocabulary-style flashcards covering homeostasis, cellular signaling, membrane transport, and tonicity based on KIN 232 lecture notes.

Physiology

The study of the biological mechanisms used to maintain the internal environment.

Homeostasis

The maintenance of a stable internal environment despite internal or external stress.

Negative Feedback

A process that opposes a change and returns a variable toward its set point.

Afferent signals

Signals that travel toward the control center.

Efferent signals

Signals that travel from the control center to the effector.

Feedback gain

A formula used to measure regulatory effectiveness, calculated as: $\text{Environmental change} \div \text{Change in the body variable}$.

Positive Feedback

A process that amplifies the original change, such as oxytocin release during labor.

Phospholipid bilayer

The primary component of the cell membrane, consisting of polar hydrophilic phosphate heads and nonpolar hydrophobic fatty-acid tails.

Saturated fatty acids

Straight fatty acids that pack closely together, making the cell membrane less fluid.

Unsaturated fatty acids

Fatty acids containing bends that make the cell membrane more fluid.

Cholesterol

A molecule that stabilizes cell membranes, is used to produce steroid hormones, and is transported via lipoproteins like LDL.

Statin side effect

Muscle soreness, weakness, or muscle damage, occurring because cholesterol is needed for muscle-cell membrane stability.

Lipophilic Hormones

Nonpolar, lipid-soluble hormones that can cross the phospholipid bilayer and bind to receptors inside the cell.

Hydrophilic Hormones

Polar, water-soluble hormones that cannot cross the bilayer and must bind to surface receptors using second-messenger systems.

cAMP Pathway

A signaling sequence where a hormone binds a receptor, activating a G protein, then adenylyl cyclase, which converts ATP to cAMP to activate protein kinase A.

Phospholipase C (PLC) Pathway

A pathway where a hormone leads to the splitting of PIP2 into IP3 (releasing intracellular calcium) and DAG (activating protein kinase C).

Electrochemical Gradient

The combined forces of a substance's concentration gradient and its electrical attraction or repulsion.

Simple Diffusion

The movement of substances (like $O_2$ or $CO_2$) from high to low concentration without requiring ATP or a transporter.

Facilitated Diffusion

The movement from high to low concentration requiring a channel or carrier protein, which has a maximum rate due to limited transporters.

Active Transport

The movement of a substance against its gradient which requires energy (ATP).

Sodium-potassium pump

A transporter that uses ATP to move $3\,Na^+$ out of the cell and $2\,K^+$ into the cell.

Secondary active transport

Transport that uses energy stored in an ion gradient rather than directly using ATP at the transporter.

Symporter

A transporter that moves two substances in the same direction, such as the sodium-glucose symporter.

Antiporter

A transporter that moves two substances in opposite directions.

Aquaporin

A specific transporter protein for water.

Osmosis

The movement of water across a selectively permeable membrane toward the side with the higher effective solute concentration.

Isotonic

A condition with equal effective solute concentration inside and outside the cell, resulting in no net water movement.

Hypertonic

An environment with a higher effective solute concentration outside the cell, causing water to leave and the cell to shrink.

Hypotonic

An environment with a lower effective solute concentration outside the cell, causing water to enter and the cell to swell.

Hyponatremia

A low concentration of sodium in the blood that creates a hypotonic extracellular environment, leading to dangerous cell swelling.

Edema

The accumulation of excess fluid in the space outside the cells.