• Senses are the physiological capacities  within organisms that provide inputs for perception.• Human beings have a multi...
• General senses are those with receptors  distributed over a large part of the body.• The general senses are widely distr...
Somatic senses• Somatic senses provide sensory  information about the body and the  environment.
Visceral senses• Visceral senses provide information  about the various internal organs.• They consist primarily of pain a...
RECEPTORS
• These are sensory nerve  endings or specialized cells  that are capable of  responding to stimuli by  developing action ...
• Mechanoreceptors- respond to  mechanical stimuli such as bending or  stretching of the receptors.• Chemoreceptors- respo...
• Free nerve endings- relatively unspecialized  neuronal branches similar to dendrites. Free  nerve endings are distribute...
• Touch receptors- structurally more  complex then free nerve endings and  many of them are enclosed in capsules
• Merkel’s disks- superficial nerve  endings in detecting light touch  and superficial pressure.• Hair follicle receptors-...
• Meissner’s corpuscles- located deep in the    epidermis, they are very specific in localizing    tactile sensations.• Pa...
• Ruffini’s end organs-  deeper tactile receptors,  plays an important role in  detecting continuous  pressure in the skin
PAIN
• Pain is a sensation characterized by a  group of unpleasant perceptual and  emotional experiences.• The two type of pain...
• Superficial pain- are sensations in  the skin that are highly localized as  a result of simultaneous stimulation  of pai...
• Local anesthesia- suppressing pain by  injecting chemical anesthetics near a  sensory receptor or nerve. This results  i...
• Referred pain is a painful sensation perceived  to originate in a region of the body that is not  the source of the pain...
Referred pain diagram
Special senses
• The senses of smell, taste, sight,  hearing, and balance are associated  with very specialized local sensory  receptors•...
• Occurs in response to airborne  molecules called odorants that  enter the nasal cavity.• Olfactory neurons are bipolar  ...
• The cilia of the olfactory cells lie in a thin  mucus film on the epithelial surface. The  mucus plays an important role...
• Airborne odorants come in contact with the  mucus on the surface of the epithelium, dissolve  and bind to the receptor m...
• The threshold for detection  of odors is very low so very  few odorants bound to an  olfactory neuron can  initiate an a...
• Odorants come in contact  with the cilia and pass  through the olfactory  receptor cells through the  cribriform plate, ...
• It stated once a odorant molecule is  bound to a receptor cell, it does no  function so prolonged exposure to a  given o...
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human anatomy project on senses (1/2)

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  1. 1. • Senses are the physiological capacities within organisms that provide inputs for perception.• Human beings have a multitude of senses, the five major are the senses of sight (ophthalmoception), hearing (audioception), taste (gustaoception), smell (olfacoception or olfacception), and touch (tactioception)• other senses include temperature (thermoception), kinesthetic sense (proprioception), pain (nociception), balance (equilibrioception) and acceleration (kinesthesioception).
  2. 2. • General senses are those with receptors distributed over a large part of the body.• The general senses are widely distributed throughout the body and include the senses of touch, pressure, pain, temperature, vibration, itch, and kinesthetic sense (proprioception).• They are divided into 2 groups, the somatic senses and the visceral senses.• Many of the general senses are associated with the skin and others are associated with the deeper structures.
  3. 3. Somatic senses• Somatic senses provide sensory information about the body and the environment.
  4. 4. Visceral senses• Visceral senses provide information about the various internal organs.• They consist primarily of pain and pressure.
  5. 5. RECEPTORS
  6. 6. • These are sensory nerve endings or specialized cells that are capable of responding to stimuli by developing action potentials.• These are associated with both special and general senses.
  7. 7. • Mechanoreceptors- respond to mechanical stimuli such as bending or stretching of the receptors.• Chemoreceptors- respond to chemicals such as odor molecules.• Photoreceptors- respond to light.• Thermoreceptors- respond to changes in temperature.• Nociceptors- respond to stimuli that result in the sensation of pain.
  8. 8. • Free nerve endings- relatively unspecialized neuronal branches similar to dendrites. Free nerve endings are distributed throughout the body .• There are different type of free nerve endings and each responds to different stimuli such as painful stimuli, itch, temperature and movement.
  9. 9. • Touch receptors- structurally more complex then free nerve endings and many of them are enclosed in capsules
  10. 10. • Merkel’s disks- superficial nerve endings in detecting light touch and superficial pressure.• Hair follicle receptors- also involved detecting light touch.- Light touch receptors are very sensitive although they are not very discriminative making it difficult to locate the point of touch.
  11. 11. • Meissner’s corpuscles- located deep in the epidermis, they are very specific in localizing tactile sensations.• Pacinian corpuscles – the deepest receptors associated with tendons and joints, relays information concerning deep vibration, pressure, and position (proprioception).
  12. 12. • Ruffini’s end organs- deeper tactile receptors, plays an important role in detecting continuous pressure in the skin
  13. 13. PAIN
  14. 14. • Pain is a sensation characterized by a group of unpleasant perceptual and emotional experiences.• The two type of pain are: – Sharp, well localized, pricking or cutting pain resulting from rapidly conducted action potentials. – Diffused, burning, or aching pain resulting from action potentials that are propagated more slowly.
  15. 15. • Superficial pain- are sensations in the skin that are highly localized as a result of simultaneous stimulation of pain receptors and the tactile receptors.• Deep or visceral pain- sensations not highly localized because of the absence of tactile receptors in the deeper structures so it is normally perceived as diffused pain.- Tactile receptors- helps localize the source of pain stimuli.
  16. 16. • Local anesthesia- suppressing pain by injecting chemical anesthetics near a sensory receptor or nerve. This results in reduced pain sensation.• General anesthesia- suppressing pain by producing a loss of consciousness and can be accomplished by chemical anesthetics affecting the reticular formation.
  17. 17. • Referred pain is a painful sensation perceived to originate in a region of the body that is not the source of the pain.• Referred pain is sensed in the skin or other superficial structures when deeper structures such as internal organs are damaged or inflamed.• This occurs because sensory neurons from the superficial area to which pain is referred and the neurons from the deeper visceral area where the pain originates converge onto the same ascending neurons in the spinal chord.
  18. 18. Referred pain diagram
  19. 19. Special senses
  20. 20. • The senses of smell, taste, sight, hearing, and balance are associated with very specialized local sensory receptors• They are localized to specific parts of the body.
  21. 21. • Occurs in response to airborne molecules called odorants that enter the nasal cavity.• Olfactory neurons are bipolar neurons within the olfactory epithelium lining the superior part of the nasal cavity.• The dendrites of the olfactory neurons extend to the epithelial surface of the nasal cavity and their ends are modified to bulbous enlargements that posses long specialized cilia.
  22. 22. • The cilia of the olfactory cells lie in a thin mucus film on the epithelial surface. The mucus plays an important role in olfaction.• Mucus- keeps the nasal epithelium moist, traps and dissolves airborne molecules and facilitates removal of molecules and particles from the nasal epithelium.
  23. 23. • Airborne odorants come in contact with the mucus on the surface of the epithelium, dissolve and bind to the receptor molecules on the membranes of the specialized. Once the dissolved odorant comes in contact receptors, it causes olfactory neurons to depolarize.
  24. 24. • The threshold for detection of odors is very low so very few odorants bound to an olfactory neuron can initiate an action potential.• Once an odor molecule is bound to the receptor, the receptor does not respond to another odor molecule for some time.
  25. 25. • Odorants come in contact with the cilia and pass through the olfactory receptor cells through the cribriform plate, to olfactory bulbs, then the signal travels through olfactory tracts and finally, it terminates in the olfactory cortex.
  26. 26. • It stated once a odorant molecule is bound to a receptor cell, it does no function so prolonged exposure to a given odorant will disable the receptor cells receiving stimuli from the smell resulting in a person adapting to a specific odor.• Once a person adapts to an odor he or she no longer smells the odor or the effect of the odor is lessened
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