S1 Final

General vs Special senses

General Senses:

General senses are associated with touch and don’t require special sensory organs.

Special Senses:

Special senses are located in the head, these collect information and are sent to the brain to be processed. Some of these include vision, smell, hearing, equilibrium, and taste.

Auditory System

The Sound Pathway:

sound waves are collected in the auditory canal of the outer ear which reaches the tympanic membrane, this causes the ossicles to vibrate. These vibrations cause movement of the fluid in the cochlea, which moves the mechanoreceptors (hair) of the inner ear. This triggers nerve impulses which are sent to the brain to be processed as sound.

Function of the Ear Muscles:

The tiny skeletal muscles of the middle ear protect against loud noises by contracting and limiting the movement of the eardrum and the ossicles, thus preventing too much movement of the cochlea liquid and mechanoreceptors.

What would happen if we didn’t have the ear muscles?:

Without these muscles, our ears would be more prone to damage. Sounds may not be as clear, since low-frequency sounds aren’t blocked. Also, we wouldn’t be protected from self-generated noises (like chewing, talking, yawning, etc)

Equilibrium & Balance

Maintaining balance:

semicircular canals contain hair and liquid, which move according to the position and movement of the head. The three semicircular canals detect tilting upwards/downwards, tilting to the right/left, and turning to the side. This information is collected by the vestibular system, processed in the brain, and sent to other organs to allow the body to maintain its balance.

Visual System

What are Rods and Cones?:

Rods and cones are photoreceptors of the eyes located in the retina.

Rods:

Rods are sensitive to low levels of light and are responsible for depth perception.

Cones:

Cones are sensitive to high levels of light and are responsible for processing colors. Because low light is processed by rods, there is less color vision in low light.

Light Refraction and Accommodation

Process of light refraction in the eye:

Light passes through and refracts off the cornea. Then, light enters the eye through the pupil, whose size adjusts to the brightness because of the iris. The light then passes and refracts off the lens, which focuses the light onto the retina. The rods and cones of the retina then convert the light to nerve impulses, that travel through the optic disc to the optic nerve.

Gustation

Detecting taste:

Taste receptors are located in the taste buds of the mouth’s papillae. These receptors make contact with the chemicals of food through taste pores. Then, nerve impulses are generated and processed in the brain as one of the taste receptors: sweet, salty, sour, bitter, and umami.

Olfaction

Smelling odors:

Odor molecules are inhaled into the nasal cavity, where they make contact with olfactory receptors. A nerve impulse is then sent to the olfactory bulb in the temporal lobe to be processed as a certain smell, which depends on which of the hundreds of olfactory receptors were triggered.

Integration of senses

Perception of flavor:

Smell and taste are both processed by chemoreceptors. As food enters and is tasted by the mouth, odor molecules travel to the naval passages. The odor and taste are both processed to create flavor, which allows the brain to process more than what the mouth can taste (sweet, sour, salty, bitter, and umami)

Application of Sensory knowledge

If a patient has difficulty hearing high pitches, what’s wrong?:

If a patient has difficulty hearing high-pitched sounds, then the receptors (hairs) of the cochlea are damaged and no longer receptive. The beginning of the cochlea is particularly damaged, which is where high-pitched sounds are detected.

S1 Anatomy Sensory Final

  • ear anatomy

    • what part converts sound waves into vibrations?

    • what part sends electrical impulses to the brain?

    • what does each part of the ear do?

    • stereocilia are the hairs of the inner ear

    • etc

  • eye anatomy

    • in what order does light pass through the eye (cornea, pupil, lens….)

    • what does each part of the eye do?

    • etc

  • gustation = taste

  • olfaction = smell

  • general senses vs special senses (FRQ)

    • location(s)?

    • what are their stimuli?

    • how are they processed, give an example.

  • Explain the process of a sense, from stimuli triggering receptors to the electrical impulse being sent to the brain (FRQ, choose an option)

    • (option 1) Hearing in the ear

    • (option 2) Sight of the eye