Physiology Flashcards
How is salty taste stimulated?
NaCl/chemical salts
How is sour taste stimulated?
H+ ions in acid
How is sweet taste stimulated?
Configuration of glucose is the reason we taste sweet
How is bitter taste stimulated?
Bitter taste is stimulated by lots of different tastants
e.g. alkaloids, poisonous substances and toxic plant derivatives
How is Umami (meaty or savoury) taste stimulated?
Triggered by amino acids especially glutamate
Aguesia
Loss of taste
What might cause loss of taste? (aguesia)
Nerve damage
Local inflammation
Some endocrine disorders
What is hypoguesia?
Reduced taste function
What might cause hypoguesia?
Chemotherapy, medications
What is dysguesia?
Distortion of taste function
Causes of dysguesia?
Glossitis, gum infections, tooth decay, reflux, upper respiratory tract infections, chemotherapy, medications, neoplasm, zinc deficiency
Deficiency of which mineral could lead to dysguesia?
Zinc deficiency
Olfacation
Smell
Where is the olfactory mucosa?
The olfactory mucosa is in the ceiling (dorsal roof) of the nasal cavity
What cells are found in the olfactory mucosa?
Olfactory receptor cells, support cells, and basal cells (secrete mucous)
Olfactory receptor life span
2 months
What are the precursors for new olfactory receptor cells?
Basal cells
Axons of olfactory receptors collectively form what?
Axons of olfactory receptors collectively form afferent fibres of the olfactory nerve
Where do afferent fibres of the olfactory nerve pierce and enter?
They pierce the cribriform plate of the ethmoid bone and enter the olfactory bulbs in the interior surface of the brain
What do olfactory bulbs do?
They transmit smell information to the brain
During quiet breathing. how do odorants reach smell receptors?
During quiet breathing, odorants only reach smell receptors by diffusion - olfactory mucoasa is above normal path of airflow
What does sniffing do?
Enhances smelling by drawing air currents upwards within the nasal cavity
To be smelled, a substance must be what?
1) sufficiently volatile
2) soluble in water
Anosmia?
Inability to smell
Causes of anosmia?
Viral infections, allergy, nasal polyps, head injury
Hyposmia?
Reduced ability to smell
-similar causes to anosmia
What may hyposmia be an early sign of?
Hyposmia may be an early sign of parkinsons!
Dysosmia?
Altered sense of smell
Examples include: differently interpreting some odours; and hallucinations of smell
Organs of taste?
Tastebuds
What do taste buds consist of?
Sensory receptor cells and support cells
Taste receptor cell life span?
10 days
What do taste receptor cells synapse with?
Synapse with afferent nerve fibres
Where are tastebuds found?
Tongue, palate, epiglottis and pharynx
