7.3 – The Senses

7.3 – The Senses

Specialized neurons in your body called sensory receptors enable you to:

1.Taste, 

2.smell, 

3.hear, 

4.see, 

5.touch

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Sensory receptors are structures that receive and respond to stimuli by generating nerve impulses

Sense Organ Receptors

Taste and Smell 

• The senses of taste and smell are:

  1.Stimulated by chemicals

  2.Often function together. 

• Smell :Specialized receptors located high in the nose respond to chemicals in the air and send the information to the olfactory bulb in the brain.

• Taste : Taste buds are areas of specialized chemical receptors on the tongue that detect the tastes of sweet, sour, salty, and bitter. These receptors detect the different combinations of chemicals in food and send this information to another part of the brain. 

Multiple Choice

The senses of taste and smell are often function together

• True

• False

Taste and Smell 

Signals from these receptors work together to create a combined effect in the brain. 

Try eating while holding your nose. You will find that your food loses much of its flavor.

Sight

• Light first enters the eye through a transparent, yet durable, layer of cells called the cornea. 

• The cornea helps to focusthe light through an opening called the pupil. 

• The size of the pupil is regulated by muscles in the iris the colored part of the eye. 

Multiple Choice

Light enters the eye through a transparent, durable, layer of cells called the

• pupil

• iris

• cornea

• lens

Multiple Choice

The cornea helps to focusthe light through an opening called

• iris

• pupil

• lens

• retina

Multiple Choice

The colored part of the eye which regulate the size of the pupil is called

• cornea

• iris

• lens

• retina

Sight

• Behind the iris is the lens, which inverts the image and projects it on to the retina.

• The image travels through the vitreous humor, which is a colorless, gelatin-like liquid between the lens and the retina. 

• The retina contains numerous receptor cells called rods and cones. 

Sight

• Rods are light-sensitive cells that are excited by low levels of light. 

• Cones function in bright light and provide information about color to the brain. 

• These receptors send action potentials to the brain via the neurons in the optic nerve

• The brain then interprets the specific combination of signals received from the retina and forms a visual image. 

Multiple Choice

the part which inverts the image and projects it on to the retina is called

• vitreous humor

• lens

• pupil

• iris

Multiple Choice

The image travels through the _________ which is a colorless, gelatin-like liquid between the lens and the retina.

• optic nerve

• vitreous humor

• iris

• cornea

Multiple Choice

____________ contains numerous receptor cells called rods and cones .

• retina

• iris

• pupil

• vitreous humor

Hearing and Balance 

• Hearing and balance are the two major functions of the ear.

• specialized receptors in the ear can detect both the volume and the highness and lowness of sounds. 

• Canals in the inner ear are responsible for your sense of balance, or equilibrium

Hearing

• Sound waves cause particles in the air to vibrate .

• The vibration causes the eardrum - at the end of the ear canal - to vibrate

• These vibrations travel through three bones in the middle ear: the malleus, the incus and the stapes.

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Hearing

• As the stapes vibrates, it causes the oval window - a membrane that separates the middle ear from the inner ear - to move back and forth.

• In the inner ear, a snail-shaped structure called the cochlea is filled with fluid and lined with tiny hair cells. 

• Vibrations cause the fluid inside the cochlea to move like a wave against the hair cells.

Hearing

• The hairs cells respond by generating nerve impulses in the auditory nerve and transmitting them to the brain. 

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Multiple Choice

Hearing and balance are the two major functions of the ear

• True

• False

Multiple Choice

Three bones the malleus, the incus, and the stapes are located in :

• Outer ear

• Middle ear

• inner ear

Multiple Choice

The oval window is __________________________

• a membrane that separates the middle ear from the inner ear

• a membrane that separates the outer ear from the middle ear

Multiple Choice

In the inner ear, a snail-shaped structure called the ___________ is filled with fluid and lined with tiny hair cells.

• cochlea

• auditory nerve

• eardrum

• malleus

Balance

• The inner ear also contains organs for balance, including three semicircular canals.

• Semicircular canals Transmit information about body position and balance to the brain

• The three canals are positioned at right angles to one another, and they are fluid-filled and lined with hair cells. 

Balance

• When the position of your head changes, fluid within the semicircular canals moves.

• This causes the hair cells to bend, which in turn sends nerve impulses to the brain. 

• The brain then is able todetermine your position and whether your body is still or in motion. 

Multiple Choice

Some rides at amusement parks cause a person to become dizzy when the ride stops. Which structure in the diagram is most likely involved with the dizzy feeling?

• A

• B

• C

• D

Multiple Choice

Where are the sensory receptors that detect your body’s position and motion?

• rods, cones

• semicircular canals

• Taste buds

• cochlea

Types of sensory receptors in the skin (temperature, pressure, pain)

• Different sensory receptors in the body respond to touch, temperature, and pain.

  
  

• All of these receptors are found in your skin, but some are also found in other areas.

Types of sensory receptors in the skin (temperature, pressure, pain)

• Thermo-receptors: aresensory cells that respond to heat and cold

• Pressure receptors:  at least seven types of sensory receptors that respond to different levels of pressure

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Types of sensory receptors in the skin (temperature, pressure, pain)

• Pain receptors: are found throughout the body, respond to physical injuries like cutting or tearing, as well as to chemicals released during infection or inflammation. 

Multiple Choice

___________are sensory cells that respond to heat and cold

• Pressure receptors

• Thermo-receptors

• Pain receptors

Multiple Choice

___________ are found throughout the body, respond to physical injuries like cutting or tearing, as well as to chemicals released during infection or inflammation.

• Thermo-receptors

• Pressure receptors

• Pain receptors

Different taste receptors and their locations on the tongue

• There are five different types of taste these receptors can detect which are recognized: 

  1.salt, 

  2.sweet, 

  3.sour, 

  4.Bitter

  5.umami. 

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Different taste receptors and their locations on the tongue

• Eachtype of receptor has a different manner of sensory transduction: that is, of detecting the presence of a certain compound and starting an action potential which alerts the brain.