the senses Flashcards
What is transduction?
The process by which external energy is converted into neural signals the brain can process.
Which senses rely on transduction?
All senses (vision, hearing, smell, taste, touch).
What kind of energy does vision detect?
Electromagnetic energy (light).
What receptors are used in vision?
Rods and cones (photoreceptors) in the retina.
What kind of energy does hearing detect?
Air pressure (sound) waves.
What receptors are used in hearing?
Hair cells on the basilar membrane (mechanoreceptors).
What kind of stimuli do smell and taste detect?
Chemical composition of odour and food molecules.
What receptors are used in smell and taste?
Chemoreceptors in the olfactory epithelium and taste buds.
What stimuli does touch detect?
Physical pressure and temperature.
What receptors are used in touch?
Mechanoreceptors and thermoreceptors in the skin.
How is sound transduced in the ear?
Hair cells in the cochlea bend against the tectorial membrane, creating neural signals.
What is the Place Theory of hearing?
Different frequencies stimulate different places on the basilar membrane.
What is the Matching Theory of hearing?
Auditory nerve activity matches the frequency of sound for low frequencies.
Where is the primary auditory cortex located?
In the temporal lobe.
What does the anterior auditory pathway do?
Identifies “what” a sound is.
What does the posterior auditory pathway do?
Locates “where” a sound is in space.
What kind of light can the human eye detect?
Visible light (a small part of the electromagnetic spectrum).
What part of the eye focuses light on the retina?
The lens.
What is the function of the retina?
Transduces light into electrical signals.
What are rods responsible for?
Vision in dim light (black and white).
What are cones responsible for?
Color vision in bright light.
What colors do cones detect?
Red (L), Green (M), Blue (S).
What do horizontal and amacrine cells do?
Integrate signals from multiple photoreceptors.
What is a receptive field?
A region of the retina sending signals to one ganglion cell.
What is the visual pathway?
Retina → Optic nerve → LGN → Visual cortex (V1).
What is a scotoma?
A blind spot in the visual field due to V1 damage.
What does V4 process?
Color perception.
What does V5/MT process?
Motion perception.
What is the dorsal visual stream?
The “where” pathway (spatial location).
What is the ventral visual stream?
The “what” pathway (object recognition).
What is the largest sensory organ?
The skin.
What do Merkel’s disks detect?
Light touch.
What do Pacinian corpuscles detect?
Deep pressure and vibration.
What do Ruffini endings detect?
Skin stretch and pressure.
What do thermoreceptors detect?
Heat and cold.
What do nociceptors detect?
Pain from mechanical, thermal, or chemical sources.
What is the dorsal-column medial-lemniscus pathway?
Carries fine touch and proprioception signals.
What is the anterolateral pathway?
Carries pain and temperature signals.
Where is the primary somatosensory cortex?
Posterior to the central sulcus.
How is the somatosensory cortex organized?
Topographically (e.g., more area for hands than legs).
Where is taste transduced?
In taste buds on the papillae of the tongue.
How is salt detected?
Sodium enters via channels, depolarizing the cell.
How is sour detected?
Hydrogen ions from acids depolarize the cell.
Why is bitterness important?
Often signals toxic substances.
What chemical is umami associated with?
Glutamate (e.g., in MSG, soy sauce).
Why is spice not a taste?
It activates pain receptors (e.g., capsaicin).
What is the gustatory signal pathway?
Taste buds → Cranial nerves → Thalamus → Insular cortex.
What is flavour influenced by?
Multisensory input: taste, smell, texture, temperature, etc.
What is the primary smell structure?
Olfactory epithelium connected to the olfactory bulb.
How does olfactory transduction work?
Odorant binds to specific receptors → mitral cells → brain.
What is unique about the olfactory pathway?
It bypasses the thalamus.
Where does the olfactory bulb project?
Amygdala, hypothalamus, hippocampus, frontal cortex.
What is anosmia?
Loss of smell (can affect flavour and mood).
What is parosmia?
Distorted smell perception.
What is phantosmia?
Smelling things that aren’t there (hallucinations).
