Lab 3 Flashcards
Mechanoreceptor
are specialized sensory nerve cells that respond to touch, pressure, sound, movement and stretch. They an detect internal and external stimuli.
proprioreceptors or Internal Machanoreceptors
Function to provide info about muscle position, contraction, movement as well as leg positioning in space.
Cockroaches have a number of mechnorecpetors of the cuticle or exoskeleton of their legs: Include:
- ) Short hairs called setae
- ) Cluster of hairs called hair plates which bend when adjoining surfaces of the cuticle contact each other in movement.
- ) Dome-like structures called Campaniform Sensilla, are distorted with the moevment of the sensilla or with the movements of the leg.
- ) Structures under the cuticle called chordotonal organs which change in length when the joint that the organ spans is extended or flexed.
Where are action potentials easily recorded?
In the cockroaches femure, because that is where the large sensory nerve passes through.
Stretch Receptors are…
(Such as chordotonal organs) are used to detetcedthe position of the leg as the cockroach moves.
Sensory Receptor Adaptation
If a stimulus is prolonged in duration the sensory receptor firing rate will decling over time, sensory receptors generally have different speeds of sensort receptor adapatation (paper on the back of the hands example)
pucinian corpuscles
in human skin have a very fast sensory receptor adaptation (clothes)
2 major sources of electrical noise:
- ) Pickup
2. ) Ground looops
Pickup electrical noise:
Can be reduced by a faraday cage, separates the source of the radiation from the electrodes. is caused by electrical radiation that produces currents in the electrodes and wires leading to the amplifiers in the recording system.
Ground Loops
Caused by ground cable itself serving as an antennae for all the noise in the room. Use cables to connect each device directly to the common grounding point.
What is the hind leg of the cockroach called?
Methathoraxic leg
What is the Coxa
is the upper portion of the lef which attaches the leg to the thorax
What is the Trochanter
acts like a knee and lets the roach bend its leg.
The femur and the tibia, what do they resemble?
resemble thing and shin bones
Tarsus acts like a….
ankle and foot
flexion
bring tibia closer to femur
Extension
Moves tibia farther way from the femur
Why will the recorded action potential vary?
Depend on the diameter of the neuron and the distance of the electrodes from the neuron. (the larger the diameter the larger amplitude of action potential and the greater the distance the smaller the amplitude of action potential. Because current dissipates over distance.
How do you calculate Firing rate?
Count the number of action potentials on the screen and divide that be recording the time in seconds.
Phasic response
If the firing ceases or is greatly reduced when movement of the receptor stops even though a new position is maintained. (rapidly adapting). this occurs when there is a change in intensity of a stimulus.
Tonic response
If action potentials continue for as long as the stimulus is maintained and slowly declining over time (slowly adapting. Typically associated with a prolonged stimulus.
Phasictonic
If the initial response to a stimulus is a burst of action potentials which is immediately followed by a large drop in firing rate that settles into a tonic pattern as the stimulus in maintained.
What is the significane of sensory receptor adaptation in the overall physiology and life of an animal?
Sensory receptors tells you when there is a new stimulus such as clothes touching your skin, however sensory receptor adaptation allows for the firing rate to declining overtime allowing the animal to focus on new stimuli.
A high firing rate is associated with a
large leg movement
