Alt muligt jeg manglede (mechano, chemo and electro)

Question 1

Describe the topology of piezo channels.

Answer 1

Homo-trimeric propeller-like structures, each subunit has at least 26 TMDs

Question 2

What ions are allowed through piezo channels?

Answer 2

Cations (non-selective)

Question 3

Describe how piezo channels can be gated.

Answer 3

Structure is curved and deforms the membrane in a dome shape way –> membrane tension will flatten the channel –> a central pore is opened

Question 4

Is the piezo channels gated by forces from lipids or forces from filaments?

Answer 4

Probably both

Question 5

Describe the topology of tandem pore domain K+-channels (K_2P channels).

Answer 5

Only the pore domains of K+ channel family x 2 => 4 TMDs dimeric

Question 6

What are the K_2P channels sensing?

Answer 6

Pain and temperature

Question 7

Explain the gating mechanism of K_2P channels.

Answer 7

There’s a lipid molecule blocking the pore, but it’sunblocked by stretching

Question 8

What is the definition of a pheromone?

Answer 8

Chemical compounds elicting specific behaviours or physiological responses in members of the same species

Question 9

Name some characteristics of pheromones.

Answer 9

Species and function specific, often complex blends (not a certain type of chemicals), active in very low concentrations, true info

Question 10

How can pheromones be delivered?

Answer 10

Either airborne or “bound” in secretions (e.g., pee)

Question 11

Describe the specificity of pheromones.

Answer 11

Usually highly specific, specificity often encoded in relative concentration of compounds

Question 12

What behaviours can be controlled by pheromones?

Answer 12

Reproductive, alarm, aggregation, trail

Question 13

How do primates do in terms of pheromone sensing?

Answer 13

They do well in overall sensitivity, but not so well in telling very simmilar compounds apart (e.g., chirals)

Question 14

What pheromone communication are thought to be found in humans?

Answer 14

Kin recognition
Mother-child recognition: starts in uterus, strengthens with breast feeding

Question 15

What are the two types of EODs found in the elephant fish and the knifefish respectively?

Answer 15

Pulsetype (elephant) and waveform (knife)

Question 16

In what mammals are electroreception found?

Answer 16

Platapus and echidnas (monotremes)

Question 17

Describe the organ used to detect electrosensation in monotremes.

Answer 17

Ampullary organ in “beak”: modified mocous gland –> sensory epithelium –> mucous production

Question 18

What can mechanical distortions/movements sensed by mechanoreceptors be caused by?

Answer 18

Direct touch, pressure waves/vibrations, gravitational pull

Question 19

Desribe the mechanosensory organ of arthropods.

Answer 19

Setea: often bimodal sensors - both mechano and chemosensory cells

Question 20

Describe the two mechanosensory organs of spiders from the lecture.

Answer 20

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)

Question 21

What organ are used for mechanosensory in fish?

Answer 21

The lateral line system

Question 22

Describe the lateral line system.

Answer 22

Capula (gel capsule) –> cilia –> sensory cells –> neurons

Capsula is moved by water –> cilia is bend –> ion channel are gated –> ion influx –> DP –> AP

Question 23

Which organs are used by many mammals to sense vibrations/flow?

Answer 23

Whiskers: modified area of the fur –> highly sensitive hair

Question 24

What can whiskers be used to detect?

Answer 24

Turbulence (hydrodynamic trail) (more than 30 secs after it was made) –> finding prey

Question 25

What are the mechanical properties of “hairs” in mechanosensory?

Answer 25

Filters selecting for frequency, direction etc.

Question 26

What are some factors changing sensitivity of mechanosensory?

Answer 26

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

Question 27

Mention some animals with hearing.

Answer 27

Most vertebrates (only some fish), cephalopods, maybe others (spiders?)

Question 28

What are hearing animals often (almost always)?

Answer 28

Sound producing, overlap but not perfect match between frequencies produced and heard

Question 29

Is it easier or harder to tell the direction of sound in water? Why?

Answer 29

Harder, because sound travels faster, and because the tissue density are app. the same as water => whole body vibrates

Question 30

What organ is used by fish to hear?

Answer 30

The swimbladder: expands/contracts with pressue waves –> ossicles transmit vibrations to inner ear –> no cochlear but ear stone, resting on hair cells

Question 31

What are active hearing?

Answer 31

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

Question 32

What kind of hearing does mosquito use?

Answer 32

Particle motion

Question 33

How can bats change the frequency and shape of the beam, and how does it change while hunting?

Answer 33

By changing the shape of the mouth.
Hunting prey: high frequency to optimize resolution.

Question 34

How does mechanoreceptors regulate food intake in fruit flies?

Answer 34

Inactivation of posterior gut neurons increases food intake, and vice versa