Chemical Senses Flashcards
How many transmembrane domains in odorant receptor genes?
7
Where are signals sent in the olfactory brain in mammals?
Primary olfactory - piriform cortex
Secondary - orbitofrontal cortex
Amygdala
Olfactory pathways project thought the ______________ to the olfactory cortex
Olfactory bulb
Sensory pathways project to ____________, which modifies and relays the information to cortical centers
Thalamus
Which pathways project to the cerebellum?
Equilibrium
Define macrosmatic
Smell necessary for survival
True or false: humans are macrosmatic
False, they are microsmatic (dont need smell to survive )
What is the difference in species that aid in odor detection?
Number of receptors they have
Describe receptor adaptation in olfactory perception
It usually fades rapidly
What structures are associated with sensing smells?
Olfactory cells
Odorant receptors (GPCR,cAMP)
VMO - sex pheromones
Which structure processes odors in the brain?
Olfactory bulb
What is the labyrinth of thin bones covered with epithelium that houses olfactory receptors?
Olfactory recess
The ________________ is the bone separating main airway
Lamina transversa
True or false: CN I has myelinated axons
False, it has unmyelinated axons
What is a unique feature of an olfactory receptor cell?
Dividing stem cell are present
List the order of signal transduction in the olfactory system
- Odor molecules enter nose
- Cilia bind to molecules
- Olfactory receptor cells in epithelium interpret molecules and relay info to brain
- Across bone, mitral cells receive and transmit odor info to brain
What proteins act as molecular switches involved in signal transmission within cells?
Guanine nucleotide-binding proteins
Can be ionotropic (fast) or metabotropic (slow)
What does the molecular mechanism of odor transduction rely on?
cAMP as 2nd messenger
From olfactory receptor cells, where does the signal go to?
CN 1
CN 1 relays info to the _________________
Olfactory bulb
Is a decline in ability to recognize odors with age normal?
Yes
What are some clinical aspects of loss of odorant recognition?
Conductive loss (polyp or inflammation) or sensorineural loss (head injury, neurodegenerative condition, upper respiratory tract infection)
What is the response to smelling pheromones called?
Flehmen response
Which organ detects pheromones?
VMO
VMO sends signals to where?
Accessory olfactory bulb
How is the Hypothalamus activation significant in humans?
- Pheromones from underarm secretions lead to menstrual synchrony
- Men can discriminate btw women high and low fertility scent samples
Define tastants
Water soluble chemicals known as adequate stimulus
What are the 5 taste primaries? Henning’s Taste tetrahedron
Sweet, sour, salty, bitter, umami
What are the 4 CN that innervate the tongue?
7, 9, 10, 5 (touch pain and temp for 5)
Fungiform, foliate, circumvallate are:
Taste papillae
Circumvate papillae are innervated by which CN?
9
Are taste cells neurons?
No, they are specialized sensory cells
responses to spicy food include:
Salivation, vasodilation, tearing, sweating, nasal secretion
CN ____ is associated with chemoreception to irritants
5
CN ____ is associated with chemoreception to irritants
5
Mentol and capsaicin activate what nociceptors
Temperature sensitive
Mentol and capsaicin activate what nociceptors
Temperature sensitive
