Homeostasis Flashcards – Cambridge IGCSE (9–1) Biology 0970 (Extended) (2026–2028)

What is a set point in homeostasis?

The normal target value of an internal condition.

How does negative feedback respond to a change away from a set point?

The change is detected and triggers responses that oppose the change.

What happens to the stimulus for negative-feedback responses as an internal condition returns towards its set point?

The stimulus diminishes.

How stable does negative feedback keep an internal condition?

Relatively stable near its set point, rather than fixed at exactly one value.

How does insulin counter a rise in blood glucose concentration?

It promotes glucose uptake by the liver and storage as glycogen, lowering blood glucose.

How does glucagon counter a fall in blood glucose concentration?

It stimulates the liver to break down stored glycogen and release glucose into the blood, raising blood glucose.

Why must insulin be supplied in Type 1 diabetes?

The body produces little or no insulin, so supplied insulin is needed to control blood glucose concentration.

What two methods are used to supply insulin in Type 1 diabetes?

• Regular insulin injections
• An insulin pump

How does blood glucose monitoring guide insulin dosing in Type 1 diabetes?

It helps adjust insulin doses in relation to food intake and physical activity.

What risk does blood glucose monitoring help reduce during insulin treatment?

The risk of blood glucose becoming too high or too low.

Does supplied insulin restore the body’s own insulin production in Type 1 diabetes?

No. It manages the condition rather than restoring the body’s own insulin production.

How are hairs positioned relative to the skin surface?

Hairs project through the skin surface.

Which structures do hair erector muscles attach to?

Hair follicles.

How are sweat glands connected to the skin surface?

Sweat glands lie within the skin, with ducts leading towards the surface.

Which cells carry impulses away from receptors in the skin?

Sensory neurones connected to the receptors.

Where are blood vessels located in the skin?

They run through the skin, including near its surface.

Where is fatty tissue located relative to the skin’s outer layers?

Beneath the skin’s outer layers.

Which organ coordinates responses that keep a mammal’s internal body temperature relatively constant?

The brain.

How does sweating cool a mammal when its body is too warm?

Sweat glands release sweat, whose evaporation removes heat.

How do arterioles supplying capillaries near the skin surface respond when a mammal is too warm?

They dilate, increasing blood flow near the surface and increasing heat loss.

How does shivering warm a mammal when its body is too cold?

Rapid muscle contractions produce heat.

How do skin-supplying arterioles respond when a mammal is too cold?

They constrict, reducing blood flow near the surface and limiting heat loss.

How do a mammal’s temperature-regulating responses affect departures from its normal internal temperature?

They oppose the departures, helping keep internal temperature relatively constant.