AQA Biology GCSE Topic 5 – Homeostasis and Response Flashcards – Key Terms, Diagrams & Exam
Practice – 100% Exam-Focused – LAST UPDATED 2025
What is homeostasis?
The maintenance of a constant internal environment, needed for enzyme action and cell functions.
Name three things homeostasis controls in the human body.
Blood glucose concentration, body temperature, and water levels.
What are the three components of all control systems?
Receptors, coordination centers, and effectors.
What do receptors do?
Detect stimuli (changes in the environment).
Give three examples of coordination centers.
Brain, spinal cord, and pancreas.
What do effectors do?
Bring about responses to bring the conditions in the body back to optimum levels (e.g., muscles or glands).
What type of cells convert a stimulus into an electrical impulse?
Receptor cells
What type of neuron carries electrical impulses to the central nervous system (CNS)?
Sensory neurons
What type of neuron carries electrical impulses from the CNS to effectors?
Motor neurons
What are reflexes?
Automatic responses that take place before you have time to think. They prevent the individual from getting hurt.
What is a reflex arc?
The pathway information travels down for vital responses to take place quickly, without going through the
conscious brain.
What happens at a synapse?
A chemical is released into the synapse that diffuses across to trigger an impulse in the next neuron.
What is the cerebral cortex responsible for?
Controls consciousness, intelligence, memory and language.
What is the cerebellum responsible for?
, Controls fine movement of muscles.
What is the medulla responsible for?
Controls unconscious actions such as breathing and heart rate.
Name three methods neuroscientists use to map brain regions.
Studying patients with brain damage, electrically stimulating parts of the brain, and using MRI scanning
techniques.
What is the function of the retina?
Layer of light sensitive cells that stimulate impulses to the brain to create an image.
What is the function of the optic nerve?
A nerve that carries impulses from the retina to the brain to create an image.
What is the function of the sclera?
White outer layer which supports the structures inside the eye.
What is the function of the cornea?
See through layer that allows light through and bends and focuses light onto the retina.
What is the function of the iris?
Muscles that surround the pupil and contract or relax to alter the size of the pupil.
What is the function of the ciliary muscles and suspensory ligaments?
Hold the lens in place and control its shape.
What happens to the ciliary muscles and suspensory ligaments when focusing on a near object?
Ciliary muscles contract and suspensory ligaments loosen.
What happens to the ciliary muscles and suspensory ligaments when focusing on a distant object?
Ciliary Muscles relax and suspensory ligaments tighten.
What is myopia?
Short sightedness, where the lens is too curved.
What is hyperopia?
Long sightedness, where the lens is too flat.
How can myopia and hyperopia be treated?
Spectacle lenses, contact lenses, laser eye surgery, and replacement lens.
Where is the thermoregulatory center found?
In the brain.
Practice – 100% Exam-Focused – LAST UPDATED 2025
What is homeostasis?
The maintenance of a constant internal environment, needed for enzyme action and cell functions.
Name three things homeostasis controls in the human body.
Blood glucose concentration, body temperature, and water levels.
What are the three components of all control systems?
Receptors, coordination centers, and effectors.
What do receptors do?
Detect stimuli (changes in the environment).
Give three examples of coordination centers.
Brain, spinal cord, and pancreas.
What do effectors do?
Bring about responses to bring the conditions in the body back to optimum levels (e.g., muscles or glands).
What type of cells convert a stimulus into an electrical impulse?
Receptor cells
What type of neuron carries electrical impulses to the central nervous system (CNS)?
Sensory neurons
What type of neuron carries electrical impulses from the CNS to effectors?
Motor neurons
What are reflexes?
Automatic responses that take place before you have time to think. They prevent the individual from getting hurt.
What is a reflex arc?
The pathway information travels down for vital responses to take place quickly, without going through the
conscious brain.
What happens at a synapse?
A chemical is released into the synapse that diffuses across to trigger an impulse in the next neuron.
What is the cerebral cortex responsible for?
Controls consciousness, intelligence, memory and language.
What is the cerebellum responsible for?
, Controls fine movement of muscles.
What is the medulla responsible for?
Controls unconscious actions such as breathing and heart rate.
Name three methods neuroscientists use to map brain regions.
Studying patients with brain damage, electrically stimulating parts of the brain, and using MRI scanning
techniques.
What is the function of the retina?
Layer of light sensitive cells that stimulate impulses to the brain to create an image.
What is the function of the optic nerve?
A nerve that carries impulses from the retina to the brain to create an image.
What is the function of the sclera?
White outer layer which supports the structures inside the eye.
What is the function of the cornea?
See through layer that allows light through and bends and focuses light onto the retina.
What is the function of the iris?
Muscles that surround the pupil and contract or relax to alter the size of the pupil.
What is the function of the ciliary muscles and suspensory ligaments?
Hold the lens in place and control its shape.
What happens to the ciliary muscles and suspensory ligaments when focusing on a near object?
Ciliary muscles contract and suspensory ligaments loosen.
What happens to the ciliary muscles and suspensory ligaments when focusing on a distant object?
Ciliary Muscles relax and suspensory ligaments tighten.
What is myopia?
Short sightedness, where the lens is too curved.
What is hyperopia?
Long sightedness, where the lens is too flat.
How can myopia and hyperopia be treated?
Spectacle lenses, contact lenses, laser eye surgery, and replacement lens.
Where is the thermoregulatory center found?
In the brain.
