Alt muligt jeg manglede (mechano, chemo and electro) Flashcards
Describe the topology of piezo channels.
Homo-trimeric propeller-like structures, each subunit has at least 26 TMDs
What ions are allowed through piezo channels?
Cations (non-selective)
Describe how piezo channels can be gated.
Structure is curved and deforms the membrane in a dome shape way –> membrane tension will flatten the channel –> a central pore is opened
Is the piezo channels gated by forces from lipids or forces from filaments?
Probably both
Describe the topology of tandem pore domain K+-channels (K_2P channels).
Only the pore domains of K+ channel family x 2 => 4 TMDs dimeric
What are the K_2P channels sensing?
Pain and temperature
Explain the gating mechanism of K_2P channels.
There’s a lipid molecule blocking the pore, but it’sunblocked by stretching
What is the definition of a pheromone?
Chemical compounds elicting specific behaviours or physiological responses in members of the same species
Name some characteristics of pheromones.
Species and function specific, often complex blends (not a certain type of chemicals), active in very low concentrations, true info
How can pheromones be delivered?
Either airborne or “bound” in secretions (e.g., pee)
Describe the specificity of pheromones.
Usually highly specific, specificity often encoded in relative concentration of compounds
What behaviours can be controlled by pheromones?
Reproductive, alarm, aggregation, trail
How do primates do in terms of pheromone sensing?
They do well in overall sensitivity, but not so well in telling very simmilar compounds apart (e.g., chirals)
What pheromone communication are thought to be found in humans?
Kin recognition
Mother-child recognition: starts in uterus, strengthens with breast feeding
What are the two types of EODs found in the elephant fish and the knifefish respectively?
Pulsetype (elephant) and waveform (knife)
In what mammals are electroreception found?
Platapus and echidnas (monotremes)
Describe the organ used to detect electrosensation in monotremes.
Ampullary organ in “beak”: modified mocous gland –> sensory epithelium –> mucous production
What can mechanical distortions/movements sensed by mechanoreceptors be caused by?
Direct touch, pressure waves/vibrations, gravitational pull
Desribe the mechanosensory organ of arthropods.
Setea: often bimodal sensors - both mechano and chemosensory cells
Describe the two mechanosensory organs of spiders from the lecture.
Slit organ: Picks up vibrations meters away - they communicate via vibrations
Trichobothia (sensilla): highly flexible socket with thin cuticle - senses vibrations/flow, very sensitive (100 times less energy than a photon moves it only a few nm)
What organ are used for mechanosensory in fish?
The lateral line system
Describe the lateral line system.
Capula (gel capsule) –> cilia –> sensory cells –> neurons
Capsula is moved by water –> cilia is bend –> ion channel are gated –> ion influx –> DP –> AP
Which organs are used by many mammals to sense vibrations/flow?
Whiskers: modified area of the fur –> highly sensitive hair
What can whiskers be used to detect?
Turbulence (hydrodynamic trail) (more than 30 secs after it was made) –> finding prey
What are the mechanical properties of “hairs” in mechanosensory?
Filters selecting for frequency, direction etc.
What are some factors changing sensitivity of mechanosensory?
The surface area of the “hair”: length and diameter - the larger the surface, the more sensitive
Mechanical properties of tissue attachment: the more regid the less sensitive
Mention some animals with hearing.
Most vertebrates (only some fish), cephalopods, maybe others (spiders?)
What are hearing animals often (almost always)?
Sound producing, overlap but not perfect match between frequencies produced and heard
Is it easier or harder to tell the direction of sound in water? Why?
Harder, because sound travels faster, and because the tissue density are app. the same as water => whole body vibrates
What organ is used by fish to hear?
The swimbladder: expands/contracts with pressue waves –> ossicles transmit vibrations to inner ear –> no cochlear but ear stone, resting on hair cells
What are active hearing?
Stereovilli perform spontanious oscillations and change their length (active process of actin part of cytoskeleton). Possible function: to amplify weak sounds, and tune certain frequencies
What kind of hearing does mosquito use?
Particle motion
How can bats change the frequency and shape of the beam, and how does it change while hunting?
By changing the shape of the mouth.
Hunting prey: high frequency to optimize resolution.
How does mechanoreceptors regulate food intake in fruit flies?
Inactivation of posterior gut neurons increases food intake, and vice versa
