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Biology 30 · Worksheets

The senses · Set B

Ten questions of mixed difficulty, covering The senses. Print it, or work through it on screen — the answer key starts on its own page.

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The senses · Set B

Biology 30 · maddyhelps.com

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Circle the best answer for each question. Show your work in the space provided.

  1. Which structure turns sound vibrations into nerve impulses?

    1. a) the eardrum
    2. b) the cochlea
    3. c) the stapes
    4. d) the pinna

  2. What happens in the eye when you focus on something close?

    1. a) The pupil gets larger
    2. b) The ciliary muscles contract and the lens becomes more rounded
    3. c) The ciliary muscles relax and the lens flattens
    4. d) The cornea changes shape

  3. Which photoreceptors in the retina detect colour?

    1. a) rods
    2. b) the iris
    3. c) cones
    4. d) the optic nerve

  4. Which statement about rods is correct?

    1. a) They detect colour in bright light
    2. b) They work in dim light but do not detect colour
    3. c) They are found only in the iris
    4. d) They are packed most tightly in the fovea

  5. Taste and smell are detected by which type of receptor?

    1. a) mechanoreceptors
    2. b) photoreceptors
    3. c) chemoreceptors
    4. d) thermoreceptors

  6. What does the Eustachian tube do?

    1. a) Detects rotation of the head
    2. b) Carries impulses to the brain
    3. c) Amplifies sound vibrations
    4. d) Equalizes air pressure on both sides of the eardrum

  7. What is the fovea centralis?

    1. a) The clear front surface of the eye
    2. b) The place where the optic nerve leaves the eye
    3. c) The spot on the retina with the sharpest vision, packed with cones
    4. d) The muscle that changes the shape of the lens

  8. At night, a faint star is easier to see if you look slightly to one side of it. Why?

    1. a) The blind spot sharpens faint light
    2. b) The image falls outside the fovea, where more sensitive rods are found
    3. c) Cones work better in dim light
    4. d) The fovea is full of rods

  9. With age, the lens loses its elasticity and near objects become blurry. What is this condition?

    1. a) astigmatism
    2. b) presbyopia
    3. c) cataracts
    4. d) myopia

  10. Which part of the eye controls how much light enters?

    1. a) the retina
    2. b) the cornea
    3. c) the lens
    4. d) the iris

Answer key · The senses · Set B

Biology 30 · maddyhelps.com

  1. b) the cochlea — Hair cells in the organ of Corti, inside the cochlea, bend as fluid vibrates and start impulses in the auditory nerve. Everything before it only passes the vibration along.
  2. b) The ciliary muscles contract and the lens becomes more rounded — Near objects need more bending of light. The ciliary muscles contract, the ligaments slacken, and the elastic lens rounds up. This is called accommodation.
  3. c) cones — Cones detect colour and work best in bright light. Rods work in dim light but only in shades of grey.
  4. b) They work in dim light but do not detect colour — Rods are very sensitive, which suits dim light, but there is only one kind, so they cannot distinguish colours. The fovea is packed with cones.
  5. c) chemoreceptors — Both senses respond to chemicals dissolved in saliva or in the mucus of the nose. Mechanoreceptors respond to touch and sound; photoreceptors to light.
  6. d) Equalizes air pressure on both sides of the eardrum — It connects the middle ear to the throat. Yawning or swallowing on a plane opens it, which is why your ears "pop".
  7. c) The spot on the retina with the sharpest vision, packed with cones — When you look straight at something, its image lands on the fovea. Its dense cones give the most detailed, colourful vision.
  8. b) The image falls outside the fovea, where more sensitive rods are found — The fovea has cones, which need bright light. Looking slightly away places the image on the rods around it, which respond to much fainter light.
  9. b) presbyopia — A stiff lens cannot round up enough for close work, so reading glasses (convex lenses) help. Cataracts are a clouding of the lens, which is a different problem.
  10. d) the iris — The iris is the coloured ring of muscle that widens or narrows the pupil. The cornea and lens focus light; the retina detects it.