Sensory Receptors Flashcards
1
Q
Folded membranes increase the following
A
– Surface area
– Amount of membrane with photopigment
– Light trapping efficiency
– Light sensitivity
2
Q
Rhodopsin
A
- 2 major components
– Opsin – lipoprotein
– does not absorblight
– Retinal – form of vitamin A – absorbs light - Changes shape when it absorbs a photon
- Light activates
3
Q
Dark Current
A
- In dark, Na+
channels open,
maintain -30mV
resting potential - Light
Hyperpolarizes
– ↓cGMP- close
channel
– Hyperpolarization
is the signal
4
Q
Visual Pigments
A
- Dark Current – in
dark Na+ channels
open, maintain -40
resting potential
– Glutamate released - Light Hyperpolarizes
– ↓ Glutamate
release
– The
hyperpolarization is
the signa
5
Q
Mechanoreception
A
- Mechanical distortion of the plasma membrane
opens ion channels
– Pressure (“touch”)
– Equilibrium
– Audition
6
Q
Pacinian Corpuscle
A
- Layers of connective tissue
- Sends signal at onset and offset of stimulus
7
Q
Note study stretch receptors
A
8
Q
Insect Bristles
A
- Directionality
- Endolymph – K + higher outside cells
- Bending opens the K+ channels
9
Q
Hair Cells (Audition and Balance)
A
- Cilia distributed over part of cell surface
- Fluid filled canals; direct water contact
- Lack axons; synaptic transmission
10
Q
Lateral Line System
A
feels disturbance vinrations which can detect prey
11
Q
Vertebrate Ear
A
- Specialization of the lateral line system
- Equilibrium
- Audition
higher frequency fade quicker, lower frequency fade slower
12
Q
External and Middle Ear
A
- Collect and Funnel Sound
- Transmit airborne vibrations to fluid filled inner ear
- Tympanic Membrane
- Auditory Ossicles
– Malleus, Incus, Stapes - Oval Window
- Amplification
– 20:1 reduction in size from eardrum to oval
window
– Bones cause 3:2 reduction in movement
– RESULT: 22-fold force ↑ at Oval Window
13
Q
Inner Ear
A
- Converts fluid vibrations
into nerve impulses - Cochlea (Mammals,
birds, crocodilians)
– Series of fluid filled
tubes
* Scala tympani and S.vestibuli (form U-shaped
tube)
* Scala media – filledwith endolymph - Basilar Membrane
- Organ of Corti
- Tectorial Membrane
14
Q
Mechanics of Cochlear Excitation
A
- Sensitive to frequency and intensity
– Long stereocilia more sensitive to low freq. - K+ and Ca2+ channels open
– NOTE depolarizing action; endolymph
15
Q
Chemoreception
A
- Contact chemoreceptors for gathering
info about the chemical environment
– General chemical sensors
– Internal chemoreceptors
– Contact chemoreceptors
– Distance chemoreceptors (olfactory)
