Topic 5 – Homeostasis and Response

    Cards (95)

    • What is homeostasis?
      Constant internal environment
    • Homeostasis is necessary for enzyme action and all cell functions
    • Blood glucose concentration is one factor controlled by homeostasis in the human body.
    • Steps in a control system for homeostasis
      1️⃣ Receptors detect stimuli
      2️⃣ Coordination centres process information
      3️⃣ Effectors bring about responses
    • Match the coordination centre with its example:
      Brain ↔️ Processes information
      Pancreas ↔️ Detects glucose levels
      Spinal cord ↔️ Coordinates reflexes
    • What is the role of effectors in homeostasis?
      Bring conditions to optimum
    • Receptor cells convert a stimulus into an electrical impulse
    • Sensory neurons carry electrical impulses to the central nervous system.
    • What do motor neurons carry electrical impulses to?
      Effectors
    • Steps in a reflex arc
      1️⃣ Stimulus detected by receptors
      2️⃣ Impulses sent along a sensory neuron
      3️⃣ Impulses pass to a relay neuron
      4️⃣ Impulses sent along a motor neuron
      5️⃣ Response by effector
    • Match the reflex arc example with its purpose:
      Pupils get smaller ↔️ Avoid damage from light
      Move hand from hot surface ↔️ Prevent injury
    • The gaps between two neurons are called synapses
    • When a chemical reaches the second neuron, it triggers a new impulse.
    • How is reaction time measured?
      Ruler drop test
    • What are the two parts of the central nervous system?
      Brain and spinal cord
    • Match the brain region with its function:
      Cerebral cortex ↔️ Consciousness and memory
      Cerebellum ↔️ Fine movement
      Medulla ↔️ Unconscious actions
    • Drugs can always reach the brain easily because of its surrounding membranes.
      False
    • Neuroscientists use MRI to create an image of the brain
    • How do neuroscientists study brain function using patients with brain damage?
      Observe changes after damage
    • Steps to focus on a near object
      1️⃣ Ciliary muscles contract
      2️⃣ Suspensory ligaments loosen
      3️⃣ Lens becomes thicker
    • Short sightedness occurs when the lens is too flat.
      False
    • What type of lens is used to treat myopia?
      Concave
    • Laser eye surgery reduces the thickness of the cornea
    • Where is the thermoregulatory centre located in the brain?
      Brain
    • The normal human body temperature is 37.5 degrees Celsius.
    • Match the response to high body temperature with its mechanism:
      Sweat production ↔️ Evaporation cools the body
      Vasodilation ↔️ More blood flows near skin
    • What is the purpose of vasoconstriction when body temperature decreases?
      Reduce heat loss
    • The endocrine system uses hormones
    • Match the gland with its hormone:
      Pancreas ↔️ Insulin
      Adrenal gland ↔️ Adrenaline
      Ovary ↔️ Oestrogen
    • What does thyroxine control in the body?
      Metabolic rate
    • Compared to the nervous system, the endocrine system is slower but acts for longer.
    • Blood glucose levels are controlled by the pancreas
    • Steps in the response to high blood glucose levels
      1️⃣ Pancreas produces insulin
      2️⃣ Insulin binds to target organs
      3️⃣ Glucose moves from blood
    • What develops during puberty to distinguish a female from a male?
      Secondary sexual characteristics
    • Testes secrete the hormone testosterone
    • The hormonal system acts faster than the nervous system.
      False
    • Why must blood glucose concentration be kept within a certain limit?
      For cell respiration
    • When blood glucose levels are too high, the pancreas produces the hormone insulin
    • Rigorous activity reduces blood glucose levels.
    • What hormone is produced when blood glucose levels decrease?
      Glucagon
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