science homeostasis and stuff

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What is homeostasis?

Homeostasis is the process by which the body maintains a relatively stable internal environment despite changes in external conditions. This includes maintaining stable temperature, pH, glucose levels, water balance, and more.

Why is homeostasis important?

It ensures the body’s internal environment remains stable for cells to function properly. Enzymes work best at specific conditions; if these change too much, enzymes stop working, leading to cell damage and illness.

What are examples of homeostasis?

• Body temperature regulation

• Blood glucose level control

• Water balance via the kidneys

• pH balance in the blood

• Breathing rate adjusted to CO₂ levels

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What is a stimulus in homeostasis?

A stimulus is any change in the internal or external environment that triggers a response, such as a rise in body temperature or low blood sugar.

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What is a receptor

Receptors are sensory structures (cells or organs) that detect changes (stimuli) in the environment. E.g., thermoreceptors detect temperature changes.

What is an effector?

An effector is a muscle or gland that responds to signals from the control center to bring about a change to maintain homeostasis. E.g., sweat glands cool the body.

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What is the general homeostasis feedback pathway?

Stimulus → Receptor → Control Center (e.g., brain) → Effector → Response

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What is negative feedback?

A mechanism that reduces or reverses a change in internal conditions to return the body to normal. For example, if the body is too hot, it triggers sweating to cool down and return to the ideal temperature range.

What is positive feedback?

A mechanism that increases the original change instead of reversing it. For example, in blood clotting, once a vessel is damaged, chemicals are released to attract more platelets, which continue to build up and seal the wound.

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What two main systems maintain homeostasis?

The nervous system and the endocrine system.

How does the nervous system help maintain homeostasis

It uses fast electrical impulses sent through neurons to quickly respond to changes (e.g., moving your hand away from something hot).

How does the endocrine system help maintain homeostasis?

It uses hormones released into the bloodstream to regulate longer-term processes like metabolism, growth, and blood glucose levels.

What is a reflex arc?

It is the pathway an impulse travels during a reflex action — an automatic, rapid response that bypasses the brain.

Steps in a reflex arc?

Stimulus → Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector → Response

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What is the function of the cerebrum?

ontrols voluntary actions, thinking, memory, decision making, and senses.

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What is the function of the cerebellum

Controls coordination, precision, and balance.

What is the function of the medulla (brainstem)?

Controls automatic processes like breathing, heart rate, and digestion.

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What are the differences between the endocrine and nervous systems?

• Nervous: Fast, uses electrical signals, short-term response

• Endocrine: Slow, uses hormones, long-lasting effects

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