1 Homeostasis and Principles of Human Physiology Free Online FlashCards

What is homeostasis?

Homeostasis is the regulation of internal conditions within ranges that support normal function, despite change.

What is the body’s internal environment?

It chiefly means extracellular fluid surrounding cells, including interstitial fluid and blood plasma.

What is a regulated variable?

A regulated variable is a condition the body monitors and adjusts, such as temperature or blood glucose.

What does a sensor do in a feedback system?

The sensor detects a change in a regulated variable and sends information onward.

How does negative feedback affect the initial change?

Negative feedback opposes the initial change, helping move a regulated variable toward its normal range.

How does insulin help regulate blood glucose after a meal?

After a meal, rising blood glucose stimulates insulin release; insulin promotes glucose uptake and storage, lowering blood glucose toward its normal range.

How does positive feedback differ from negative feedback?

Positive feedback reinforces the initial change, amplifying a process until an event is completed or another mechanism stops it.

How does positive feedback contribute to childbirth?

Cervical stretching promotes signals that strengthen uterine contractions; the stronger contractions increase stretching until delivery.

What is anticipatory (feedforward) regulation?

Anticipatory, or feedforward, regulation begins a response before a regulated variable changes substantially, preparing for expected demand.

What is one example of feedforward regulation at exercise onset?

As exercise begins, nervous system activity can increase heart rate and breathing before the body’s needs become fully apparent.

Which internal conditions do the kidneys help regulate over time?

The kidneys help regulate water, electrolytes, and acid–base balance over longer periods.

Why can homeostasis fail to fully compensate for a disturbance?

Homeostatic responses have limits: a disturbance that is too large, persistent, or damaging may exceed the body’s ability to compensate fully.