Quick revision: every question with its correct answer. For the full explanation, open the relevant test and tap View Solution.
6.4 Sense Organs — Test 1
Q1. The light-sensitive (photoreceptor) layer of the eye is the:✓ Retina
Q2. The photoreceptors responsible for colour vision are the:✓ Cones
Q3. The photoreceptors that function in dim light (night vision) are the:✓ Rods
Q4. The absorption of light by retinal cells converts the visual pigment by changing:✓ Retinal (from cis to trans form) in rhodopsin
Q5. The transparent front part of the eye that does most of the light bending (refraction) is the:✓ Cornea
Q6. Accommodation (focusing on near objects) is achieved by changing the shape of the:✓ Lens
Q7. The amount of light entering the eye is controlled by the:✓ Iris (adjusting the pupil)
Q8. The Pacinian corpuscle is a sensory receptor that detects:✓ Pressure and vibration
Q9. The receptors for hearing (sound) are located in the:✓ Cochlea of the inner ear
Q10. The sense of balance and head position depends on the:✓ Vestibular apparatus (semicircular canals and otolith organs)
Q11. The taste sensation 'umami' is produced by the detection of:✓ Glutamate (amino acids)
Q12. The receptors for smell (olfaction) are located in the:✓ Olfactory epithelium of the nasal cavity
Q13. The blind spot of the eye corresponds to the point where:✓ The optic nerve leaves the retina (no photoreceptors)
Q14. The fovea centralis of the retina provides the sharpest vision because it contains:✓ A high density of cones
6.4 Sense Organs — Test 2
Q15. The middle ear transmits sound vibrations to the inner ear through three small bones called the:✓ Ossicles (malleus, incus, stapes)
Q16. The pigment in rod cells responsible for dim-light vision is:✓ Rhodopsin
Q17. Vitamin A deficiency impairs vision by reducing the formation of:✓ Rhodopsin (causing night blindness)
Q18. The structure that focuses an inverted image onto the retina is the:✓ Lens (with the cornea)
Q19. The sense organs convert (transduce) stimuli into:✓ Nerve impulses (electrical signals)
Q20. Sound localisation in the horizontal plane relies on the brain comparing:✓ The timing and intensity of sound at the two ears
Q21. The phototransduction in rods is triggered when light causes:✓ Closure of cation channels, hyperpolarising the rod
Q22. The transparent crystalline structure that fine-tunes focusing in the eye is the:✓ Lens
Q23. Detection of odours (smell) is mediated by receptor neurons using:✓ G-protein-coupled odorant receptors
Q24. Perception of taste depends mainly on:✓ A mix of ion channels and G-protein-coupled receptors
Q25. The excitation of auditory hair cells occurs when their stereocilia are:✓ Deflected, opening mechanically gated ion channels
Q26. The outer hair cells of the organ of Corti function mainly to:✓ Amplify and tune the response to sound
Q27. Rhodopsin, the visual pigment of rods, is best described as a:✓ Photosensitive G-protein-coupled receptor
6.4 Sense Organs — Test 3
Q28. The semicircular canals of the inner ear detect:✓ Rotational (angular) movements of the head
Q29. The otolith organs (utricle and saccule) detect:✓ Linear acceleration and the pull of gravity
Q30. Sound waves are converted to nerve impulses by hair cells located in the:✓ Organ of Corti within the cochlea
Q31. The mechanism that allows us to locate the source of a sound horizontally uses differences between the two ears in:✓ Timing and loudness of the sound
Q32. Different pitches of sound are distinguished because different regions of the basilar membrane:✓ Vibrate maximally to different frequencies
Q33. Refraction of light entering the eye is greatest at the:✓ Cornea (air–cornea interface)
Q34. Colour blindness most commonly results from a defect or absence of certain:✓ Cone photopigments
Q35. Adaptation of the eye to dim light (dark adaptation) depends largely on regeneration of:✓ Rhodopsin in the rods
Q36. The sensory receptors that detect pain are called:✓ Nociceptors
Q37. The receptors that detect temperature changes in the skin are the:✓ Thermoreceptors
Q38. The blind spot of the human eye is located where the:✓ Optic nerve leaves the retina
Q39. Light must pass through several retinal layers before reaching the photoreceptors because the vertebrate retina is:✓ Inverted (photoreceptors at the back)
Q40. The middle layer of the eyeball, rich in blood vessels and pigment, is the:✓ Choroid
6.4 Sense Organs — Test 4
Q41. The receptor type giving the sharpest, most detailed daytime vision is the:✓ Cone
Q42. The fluid filling the large rear chamber of the eye, helping maintain its shape, is the:✓ Vitreous humour
Q43. The structure that adjusts the curvature of the lens for accommodation is the:✓ Ciliary muscle
Q44. The eardrum (tympanic membrane) functions to:✓ Vibrate in response to sound and transmit it to the ossicles
Q45. The Eustachian (auditory) tube connects the middle ear to the:✓ Pharynx (throat), equalising pressure
Q46. Adaptation of a sensory receptor means that, with a constant stimulus, its response:✓ Decreases over time
Q47. The rapidly adapting skin receptor that detects vibration and rapid pressure changes is the:✓ Pacinian corpuscle
Q48. The image formed on the retina is:✓ Real and inverted
Q49. Loss of high-frequency hearing with age, due to hair-cell damage, is called:✓ Presbycusis
Q50. The part of the ear that contains both hearing and balance organs is the:✓ Inner ear
Q51. The five basic tastes detected by the human tongue are sweet, sour, salty, bitter and:✓ Umami
Q52. The receptors for touch and pressure, along with those for pain and temperature, are examples of:✓ Cutaneous (skin) receptors
Q53. The point of sharpest vision on the retina, packed with cones, is the:✓ Fovea centralis