Homeostasis and Feedback Concepts (Video Notes)

A set of practice flashcards covering homeostasis, negative and positive feedback, set points, feedback loop components, gradients, and terminology concepts discussed in the video notes.

What is homeostasis?

The body's ability to detect changes in the internal/external environment and activate mechanisms that oppose those changes to maintain a relatively stable internal state.

What is a set point in physiology?

The target value for a physiological variable (e.g., heart rate, blood pressure, core temperature) around which a normal range is maintained.

What is negative feedback?

A mechanism where a change is sensed and opposite actions are initiated to bring the variable back toward the set point, creating dynamic equilibrium within a range.

How does the body respond to heat via negative feedback?

Skin blood vessels vasodilate and sweating begins to cool the body.

How does the body respond to cold via negative feedback?

Skin blood vessels vasoconstrict and shivering occurs to generate heat.

Why is maintaining homeostasis important?

Losing homeostasis can lead to illness or death; extreme fever or prolonged hypothermia are dangerous.

What is positive feedback?

A self-amplifying cycle that drives a rapid change in the same direction, not a corrective action; examples include childbirth and blood clotting.

What are the three components of a feedback loop?

Receptor (sensor), integrating center (control center, e.g., brain), and effector (cell or organ that produces the response).

What is the role of baroreceptors in maintaining blood pressure?

Baroreceptors in the neck sense changes in blood pressure and relay information to the brain to adjust heart rate and maintain cerebral perfusion.

Describe the thermostat analogy for negative feedback.

If room temperature falls below the set point, the thermostat activates the furnace to raise the temperature to the set point, then turns off; the cycle maintains a stable temperature.

What is a gradient in physiology?

A difference in a property (pressure, temperature, chemical concentration, or electrical potential) between two points that drives movement from high to low.

What are common types of gradients mentioned?

Pressure gradient (high to low pressure), chemical concentration gradient (high to low concentration), electrical gradient (positive vs negative charges), combined chemical-electrical gradient, and thermal gradient (heat flow from hot to cold).

What does it mean to move down a gradient?

Movement from high to low, which is passive and requires no energy.

What does it mean to move up a gradient?

Movement from low to high, which requires energy input.

Why is Latin terminology and word formation discussed in these notes?

Many anatomical terms come from Latin; prefixes/suffixes modify base terms; understanding roots helps decipher meanings, and there are acronyms and plurals to learn (e.g., cortex -> cortices, foramina vs foramen).