Topic 5 Homeostasis and Response

    Cards (170)

    • What is homeostasis?
      The maintenance of a constant internal environment
    • Why is homeostasis necessary for the body?
      It is needed for enzyme action and all cell functions
    • What does homeostasis control in the human body?
      • Blood glucose concentration
      • Body temperature
      • Water levels
    • What role do nervous and hormonal communication play in homeostasis?
      They are involved in automatic control systems that detect changes and respond to them
    • What are the components of control systems in homeostasis?
      • Receptors: detect stimuli
      • Coordination centres: process information
      • Effectors: bring about responses
    • What are receptors in the context of homeostasis?
      Cells that detect stimuli (changes in the environment)
    • What is the function of coordination centres in homeostasis?
      They process the information received from the receptors
    • What are effectors in the homeostasis control system?
      Muscles or glands that bring about responses
    • What is the role of the nervous system?
      It allows us to react to our surroundings and coordinate actions in response to stimuli
    • What do receptor cells do?
      Convert a stimulus into an electrical impulse
    • How does an electrical impulse travel in the nervous system?
      It travels along sensory neurons to the central nervous system (CNS)
    • What happens in the CNS after receiving an electrical impulse?
      The information is processed and an appropriate response is coordinated
    • What are motor neurons responsible for?
      Sending electrical impulses to effectors
    • What are reflexes?
      Automatic responses that occur before you have time to think
    • What is a reflex arc?
      1. A stimulus is detected by receptors
      2. Impulses are sent along a sensory neuron
      3. The impulse passes to a relay neuron in the CNS
      4. Impulses are sent along a motor neuron
      5. The impulse reaches an effector resulting in a response
    • What is an example of a reflex arc?
      Pupils getting smaller to avoid damage from bright lights
    • What are synapses?
      Gaps between two neurons
    • What happens when an impulse reaches the end of the first neuron at a synapse?
      A chemical is released into the synapse
    • How does the chemical released at a synapse affect the second neuron?
      It triggers the impulse to begin again in the next neuron
    • What is reaction time?
      The time it takes to respond to a stimulus
    • How can reaction time be measured?
      With the ruler drop test
    • What is the brain made up of?
      Many connected neurons
    • What does the cerebral cortex control?
      Consciousness, intelligence, memory, and language
    • Where is the cerebellum located?
      Towards the bottom/back of the brain
    • What is the function of the medulla?
      Controls unconscious actions such as breathing and heart rate
    • Why is investigating brain function difficult?
      • The brain is complex and delicate
      • It is easily damaged
      • Drugs cannot always reach the brain
      • It is not fully understood which part does what
    • How do neuroscientists map out brain regions?
      By studying patients with brain damage, electrically stimulating parts of the brain, and using MRI scanning techniques
    • What can studying patients with brain damage reveal?
      Information on the role of specific brain areas
    • What does electrically stimulating different parts of the brain involve?
      Pushing an electrode into the brain to observe changes
    • What is the purpose of MRI scanning techniques?
      To create an image of the brain and show affected areas
    • What is the function of the retina?
      It contains light-sensitive cells that send impulses to the brain
    • What does the optic nerve do?
      It carries impulses from the retina to the brain
    • What is the sclera?
      The white outer layer of the eye that supports its structures
    • What is the function of the cornea?
      It allows light through and bends it to focus on the retina
    • How does the iris control pupil size?
      By contracting or relaxing muscles that surround the pupil
    • What happens to the pupil in bright light?
      The circular muscles contract and radial muscles relax
    • What happens to the pupil in dim light?
      The circular muscles relax and radial muscles contract
    • What is the process of accommodation in the eye?
      To focus on a near object:
      • Ciliary muscles contract
      • Suspensory ligaments loosen
      • Lens becomes thicker and more curved

      To focus on a distant object:
      • Ciliary muscles relax
      • Suspensory ligaments tighten
      • Lens becomes thinner
    • What is myopia?
      Short sightedness where distant objects appear blurry
    • What is hyperopia?
      Long sightedness where the lens is too flat
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