The document discusses the 5 basic human senses and related sensory organs. It describes the sensory receptors for smell (olfactory cells), hearing and balance (hair cells in the inner ear), sight (rods and cones in the retina), taste (taste buds on the tongue and palate) and touch (mechanoreceptors in the skin). For each sense, it outlines the key structures involved and how sensory stimuli are transmitted to the brain for perception.

1. SENSE ORGANS
G O O D M A N S N KO S I

2. 5 SENSES

3. 1. SENSE OF SMELL
• Receptor cells of smell are OLFACTORY CELLS
• Olfactory cells are located within olfactory epithelium high in the roof of
the nasal cavity

4. SENSE OF SMELL

5. PERSEPTION OF SMELL
• The gas molecules in the air dissolves in the mucus of the
nasal cavity.
• It stimulates the microvilli of olfactory cells.
• This cause an impulse to be send from olfactory cell through
the sensory nerve fibres, to the olfactory bulb in the temporal
lobe of the cerebrum.
• Smell is integrated and perceived

6. SENSE OF HEARING AND BALANCE
• The ear has two sensory functions: Hearing and Balance.
• The sensory receptors for both of these is located in the inner ear, and each consist of
hair cells and cillia which are sensitive to mechanical stimulation. They are called
machanoreceptors.

7. STRUCTURE AND FUNCTION OF
HUMAN EAR
• Pinna – Concentrate sound waves in the direction of the external
auditory canal.
• External Auditory canal
• – Transport sound waves from the pinna to the tympanic membrane.
• - Contain fine hairs and cerumin glands that secrete cerumin (earwax) to
help guard the ear against foreign material and insects. (smell)
• Tympanic membrane
• – A thin membrane that covers the opening between the inner- and
middle ear.
• - Converts soundwaves into vibrations. (starts to vibrate)

8. HUMAN EAR
• 3 Bony ossicles e.g.: (start to vibrate):
• - Malleus – transmit vibration to incus
• - Incus – transmit vibrations to stapes
• - Stapes – transmit vibrations to window (fenestra ovalis)
• Oval window – start to vibrate and cause waves in liquid (perilymph) in cochlea.
• Eustachian tube – Equalize the pressure between the atmosphere and the inside of the
ear. (Connected with the pharynx)

9. INNER EARCochlea:
- Snail shaped canal.
- Divided in 3 canals
- separated by membranes
1. Vestibular canal (scale vestibuli) – top canal, filled with perilymph. Receives vibration from oval window,
form waves in perilymph, causes Reissner membrane to form waves.
• Cochlear canal (Scala media) – middle canal, filled with endolymph.
• Form waves in endolymph, that causes Basilar membrane to wave up and down.
• Contains the receptor cells for hearing: Organ of Corti - which pushes the stereocilia against the
tectorial membrane, causes an impulse which is send through the cochlear nerves to the
temporal lobe of the brain for integration
• Tympanic canal (Scala tympani)– bottom canal, filled with perilymph. Form waves which are
carried to the round window (fenestra rotunda).
• Round Window: absorb excess sound waves to prevent echoing in the ear

10. SENSE OF SIGHT
Three main parts of the eye
1. Outer layer (Cornea, Sclera)
2. Middle layer (Choroid, ciliary body, iris)
3. Inner layer (Retina – rods, cones, fovea)

11. THE HUMAN EYE
Most important part of the human eye
• Lens (Attach to suspensory ligaments)
• Humors (Aqueous humor and vitreous humor – Transmit light rays and
support eyeball)
• Optic nerves – Transmits impulses to the brain
The outer part and functions
• The sclera: white outer layer, protects and supports eyeball
• Cornea: Front transparent part of eye. Refracts light rays
• Conjunctiva: Transparent membrane (front). Moistens eye surface

12. THE MIDDLE PART OF HUMAN EYE
• Pupil: Hole in middle of eye. Black. Admits light into
eye.
• The choroid: Pigmented 2nd layer. Absorb stray light.
Contain blood vessels for nutrition and oxygen.
• The iris: Coloured part of the eye that regulates the
size of the pupil and therefore light entrance
• The lens: Transparent biconvex structure that refract
and focuses light on the retina

13. THE INNER PART OF HUMAN EYE
• The retina: contains photoreceptors (cones and rods)
- Rods: Make black and white vision possible/ overview
sight
- Cones: Make colour vision possible
- Fovea centralis: Best image possible
- Blind spot: place where nerves and blood vessels
enter and leave the eyeball. No image can be seen if
light is focused on this point.

14. HUMAN EYE
• The eye is divided into two cavities separated by the lens and cilliary body:
• The anterior cavity is filled with watery aqueous humor.
• The posterior cavity is filled with jellylike vitreous humor.
• The cilliary body produces the aqueous humor
• ACCOMODATION
• The ability of the lens to change shape to enable the eye to focus on near and far
objects.= accommodation

15. 3 TYPES OF PAPILLAE

16. FUNCTIONS OF TASTE BUDS
• Chemical molecules in food, dissolve in the saliva.
• The molecules bind to the receptor proteins in the
microvilli of the taste buds.
• This stimulates the taste cells to send an impulse through
the sensory nerve fibers.
• Impulse move to the parietal lobe of cerebrum.
• Taste is interpreted

17. 5 TYPES OF TASTE
1. Sweet
2. Sour
3. Bitter
4. Umami
5. Salty

18. SENSE OF TASTE
• Taste receptors = TASTE BUDS
• Taste buds are located on tongue(mainly), hard palate,
pharynx and epiglottis.
• The tongue very rough, due to numerous papillae.
• 3 Types of papillae:
- Fungiform- found on front and sides of tongue.
- Foliate found on front 2/3 of tongue
- Curcumvallate- found on the back of the tongue.
• The taste buds are located on the papillae.

19. SENSE ORGAN SKIN
• Mechanoreceptors sense physical deformation caused by stimuli such as pressure,
stretch, motion, and sound
• The sense of touch in mammals relies on mechanoreceptors
• Thermoreceptors, which respond to heat or cold, help regulate body temperature by
signalling both surface and body core temperature
• Pain receptors, or nociceptors, respond to excess heat, pressure, or chemicals released
from damaged or inflamed tissues.
• The sensory cutaneous mechanoreceptors in the skin are:
• Ruffini's end organ (sustained pressure and heat – all over body)
• Meissner's corpuscle (changes in texture, slow vibrations – light touch – lips, finger
tips)
• Pacinian corpuscle (deep pressure, fast vibrations – visceral organs)
• Merkel's disc (sustained touch and pressure)
• Free nerve endings (pain – all over body)
• End bulbs of Krause – cold – all over body

20. STRUCTURE OF HUMAN SKIN

21. THE SKINS SENSORY CUTANEOUS
MECHANORECEPTORS ARE

22. REFERENCES
Haq, N. (2017) human sense organ. Available from slideshare at:
https://www.slideshare.net/NOORULHAQ20/human-sense-organs-
78479516?qid=49705910-c7b8-44c3-b6fc-93807e174b63&v=&b=&from_search=1 [
Assessed 13 September 2017]
Yudianto, A. (2013) The human nervous system and sense organ. Available from
slideshare at: https://www.slideshare.net/anikyudianto/the-human-nervous-system-and-
sense-organ?qid=ca82cb87-a5af-4885-a9bb-9f3befa9f9f3&v=&b=&from_search=13 [
Assessed 13 September 2017]
Kennedy, S. (2007) Introduction to nervous system. Available from slideshare at:
https://www.slideshare.net/mrskennedy/introduction-to-nervous-system [ Assessed 14
September 2017]
Ternio, E. (2016) Sense organs of the human body. Available from slideshare at:
https://www.slideshare.net/katnisshetan/sense-organs-of-the-human-
body?qid=ca82cb87-a5af-4885-a9bb-9f3befa9f9f3&v=&b=&from_search=15 [ Assessed
13 September 2017]

23. REFERENCES
CASTEJON, T. (2015) My sense of taste mix. Available from slideshare at:
https://www.slideshare.net/Teachersteam/my-sense-of-taste-mix [ Assessed 14
September 2017]
Khan, B. (2013) 56514243 physiology-of-hearing-balance. Available from slideshare at:
https://www.slideshare.net/sweetburhan/56514243-
physiologyofhearingbalance?qid=9308c66d-96c5-4ae6-998a-
0d053ebd1d59&v=&b=&from_search=2 [Assessed15 September 2017]
Lizz, A. (2011) The ears, hearing, and balance presentation . Available from slideshare at:
https://www.slideshare.net/Angie_Lizz/the-ears-hearing-and-balance-presentation-
presentation?qid=a406d09d-e7b0-4519-a8bc-75c258e65544&v=&b=&from_search=4
[Assessed15 September 2017]