Sense of Smell By: Hrag Peltekian & Matthew Park Olfactory
System
Slide 2
Structure- Outer Part The olfactory system is the sense of
smell within eukaryotes. In humans, the outer skin part of the nose
is made of the external meatus. It is the triangular shaped bone in
between the eyes. This bone holds the shape of the nose. The
nostrils are separated into two sections by the septum. The septum
is made of cartilage, bone, and mucus membranes.
Slide 3
Structure- Inner Part Inside the two sections are nasal
passages. Within these passages are hairs that act like filters
called cilia. Also, the mucus membranes are lined up to assist the
cilia and clean unnecessary waste while breathing in oxygen. The
Olfactory Bulb is also located towards the inner part of the nose.
The Olfactory Bulb is the part of the nose that sends signals to
the brain to identify a certain smell.
Slide 4
Slide 5
Function Can be divided into two parts: - Peripheral: Olfactory
receptor sense external stimulus and encode it as electric signal
in neurons. Signal travels along olfactory nerve. - Central: Signal
terminates at olfactory bulb. Axons in the olfactory neurons tangle
to form glomeruli, in which they contact dendrites of mitral cells
that send the axons to the limbic system of the brain.
Slide 6
A person's sense of smell is driven by certain processes: 1. A
molecule released from a substance, like the fragrance of a flower,
must stimulate special nerve cells called olfactory cells (located
high up in the nose) 2. Olfactory cells send information to the
brain to identify the specific smell. 3. Interferences such as
nasal congestion, nasal blockage, or damage to the nerve cells
themselves can lead to loss of smell, even permanently. Olfactory
receptors can regenerate, however.
Slide 7
Diseases/Disorders One disease that is part of the olfactory
system is called Anosmia. Anosmia is a disorder in which you lose
the sense of smell. Hyposmia is also a disorder, but this has a
decreased ability to smell.
Slide 8
Dysomia, the disease in which one has a distorted smelling
ability. Divided into three categories. Parosmia- changed sense of
order. It is usually an unpleasant smell. Phantosmia- senses odor
when no odor present. Agnosia- able to sense odors but unable to
identify or differentiate smells.
Slide 9
Slide 10
Human receptors can detect up to 5,000 odors, rather than
having different receptors for specific odors. Women detect odors
more easily than men.
Slide 11
Quiz 1. Which nerve cells detect odors? A. Dendrite cells B.
Glomeruli cells C. Olfactory cells D. Brain cells
Slide 12
Quiz Answer: C. Olfactory Cells
Slide 13
Quiz 2._____ in the olfactory cells tangle to form glomeruli.
A. Dendrites B. Axons C. Bulbs D. Fragrances
Slide 14
Quiz Answer: B. Axons
Slide 15
Quiz 3. Olfactory receptors can regenerate. A. True B.
False
Slide 16
Quiz Answer: A. True
Slide 17
Quiz 4. Which of the following statements is not true? A.
Olfactory receptors detect odors to send to the brain B. The brain
identifies the specific odor C. The olfactory system consists of
two parts, peripheral and central D. Humans have different
receptors for different odors
Slide 18
Quiz Answer: D. Humans have different receptors for different
odors
Slide 19
Quiz 5. Which of the following is true? A. Women detect odors
more easily than men B. Men detect odors more easily than women C.
Men and women have an equal ability to detect odors D. A persons
sex does not affect his/her ability to detect odors
Slide 20
Quiz Answer: A. Women detect odors more easily than men
Slide 21
Quiz 6. The septum is made of which of the following: A. Bone
B. Cartilage C. Mucus Membrane D. All of the above
Slide 22
Quiz Answer: D. All of the above.
Slide 23
Quiz 7. Dysomia is the disorder in which: A. No smell is
detected B. Lessened sense of smell C. Distortion of smell D.
Olfactory Bulbs do not work
Slide 24
Quiz Answer: C. Disorder of smell.
Slide 25
Quiz 8. Humans can detect up to how many smells? A. 500 B. 50
C. 5 D. 5000
Slide 26
Quiz Answer: D. 5000
Slide 27
9. The outer part of human noses which hold the shape of the
nose are made up of: A. Mucus B. External Meatus C. Olfactory Cells
D. Olfactory Bulbs
Slide 28
Quiz Answer: B. External Meatus
Slide 29
Quiz 10. What is the function of the cilia? A. Identify the
smell of an odor. B. Send signals to the brain of a smell. C. Block
the nasal passage. D. Filter the debris about to enter the inner
part of the nose.
Slide 30
Quiz Answer: D. Filter the debris about to enter the inner part
of the nose.
Slide 31
Bibliography Anosmia: Symptoms, Causes, and Treatments. WebMD.
Web. 12 May 2013.. Olfactory System Quiz Preparation. Quizlet, n.d.
Web. 13 May 2013.. Disorders of Taste and Smell. WebMD. 12 August
2012. Nose Structure. Bayer HealthCare LLC.
