Mechanoreceptors

Question 1

What are receptors?

Answer 1

nerve/epithelial tissue responding to stimuli by developing action potentials

Question 2

What are primary and secondary receptor cells?

Answer 2

primary receptor cells are specialized neurons and secondary cells are epithelial cells

Question 3

What is a stimulus?

Answer 3

any environmental parameter causing a response in a nerve muscle or gland

Question 4

What is a sensation?

Answer 4

perception or awareness of a stimulus received by sensory receptors

Question 5

What are general senses?

Answer 5

senses that are superficial and deep afferent neurons that carry the signal from PNS to CNS such as on the skin surface

Question 6

WHat are the special senses?

Answer 6

sensory modalities that are specialized that are designed to pick up a specific type of stimuli and often are hardwired into the brain as cranial nerves

Question 7

What is one component that separates the special senses from the general senses?

Answer 7

The special senses normally have an accessory component or many accessary components associated with them- things that help to shape or filter the signal before it gets to the receptor

Question 8

What are naked neurons?

Answer 8

Neurons that do not have a myelinated sheath.

Question 9

What is sensory coding?

Answer 9

receptor sensitivity for each type of stimulus to elicit a unique different response

Question 10

How do you recognize the difference between senses?

Answer 10

By where the sense ends up in the brain not bc of the receptor

Question 11

What are the morphological considerations when referring to the different types of receptors?

Answer 11

1. Filtering-to pick up different types
2. Amplification-connect receptors so its additive to make signal stronger

change the receptors so they are specific to a certain type of information they can code for

Question 12

What are three types of signal filtering?

Answer 12

1. low pass filters-pick up low frequencies
2. high pass filters-pick up high frequencies
3. band pass filters-sensitive to a certain series of frequencies within a range

Question 13

WHat do general mechanoreceptors respond to?

Answer 13

sheer or torque forces

Question 14

What is the structure of general mechanoreceptors?

Answer 14

Undifferentiated neurons with few processes and naked neurons lacking myelin sheath.

Question 15

What is the mode of mechanoreceptor stimulation?

Answer 15

direct distortion

Question 16

WHat are the two different ways in which a signal can be coded?

Answer 16

1. tonic receptors-receptor sends off a pulse continuously

2. phasic receptors-spiked

Question 17

What are Meissner’s corpuscles sensitive to?

Answer 17

touch and pressure

Question 18

What are free undifferentiated nerve endings sensitive to?

Answer 18

Nociception and we register it all as pain.

Question 19

what are the two groups of nociceptors?

Answer 19

1. fast response nociceptors-pick up sharp well localized type of pain ex:step on nail
2. slow propagation nociceptors-sense of burning or achy pain and are very diffused ex:cold hurt everywhere

Question 20

What and where are propriorecptors?

Answer 20

Found in the Pacinian corpuscles. Sense deep pressure within muscles/joints, can pick up vibrations and position or bending moment in joints.

And also help you to walk or run that you don’t think about transfer back to cerebellum.

Question 21

What are the thermoreceptors?

Answer 21

receptors for temperature. Found on the surface of the skin and tongue. unmyelinated neurons.

Question 22

What are the only receptors in the brain?

Answer 22

Thermoreceptors in the hypothalamus and also integrates temp info coming form the periphery of the skin.

Question 23

What are infrared receptors in pit vipers and what do they actually sense?

Answer 23

Membrane in the pit organ is covered with specialized neurons that are sensitive to temperature. Infrared radiation comes in through an opening strikes the membrane and heats it up. A tiny change in temperature as little as .002 degrees is enough to send off an action potential to the brain that also forms images. Most sensitive receptor known.

Question 24

Why do we see so many special sense cells with secondary sense cells (epithelial tissue) and nor primary sense cells (nerves)?

Answer 24

Secondary sense cells give a graded response and Primary sensory cells are nerves that give an all or none response.

Question 25

What is the advantage of a graded response?

Answer 25

Gives a more sophisticated signal that can send more complex information.

Question 26

What are hair cells?

Answer 26

special epithelial cell that is sensitive to sheer or torque forces

Question 27

What is the structure of hair cells?

Answer 27

There is an apical surface that is exposed to the stimulus and a basal surface that synapses with the interneurons or motor neuron.

Question 28

What are the cell processes on the apical portion of the hair cells? and how do they work?

Answer 28

1. kinocilium-long process, was once a cillia or flagella and has 9+2 arrangement microtubules
2. stereocilia- always shorter than kinocilia. not like cilia more like microvilli

polarity in cell from top to bottom and radial polarity

When you move the hair cells in various ways get different types of signals.

Question 29

What is a statocyst?

Answer 29

A cavity that is fluid filled with patches of hair cells in the opening. A statolith is in the cavity and is more dense than the fluid or material the organism is in. In vertebrates this is called an end organ.

Question 30

What is the function of the statocyst?

Answer 30

The fluid filled cavity id more dense than the fluid it is in causing the hair cells the hair cells to sink and in this way the organism can determine what is upright based on the gravity.

Question 31

In fish what is the endorgan that is more dense than water called?

Answer 31

otolith

Question 32

How can the endorgans be used to determine angular momentum and acceleration/

Answer 32

They must be modified and they are expanded into 3 semicircular canals that are at right angles to one another and each one in a different orientation in space. There are ampullae that are swellings that contain the hair cells. In the semicircular canals is fluid and the fluid moves the hair cells.

Question 33

What is the gelatinous mass associated with the hair cells that moves with the movement of the fluid in the semicircular canals?

Answer 33

cupula and they act in unison as a waving flag and also creates a pressure and we can determine acceleration and angular momentum

Question 34

static equilibrium

Answer 34

gravity

Question 35

kinetic equilibrium

Answer 35

acceleration movement speed

Question 36

What is and where is the naked neuromast found?

Answer 36

Found in fish and amphibians. It is made of hair cells and cupula that allows fish to use the lateral line system

Question 37

What is the lateral line system?

Answer 37

Water movement across the neuromast stimulates the cupula and thus the hair cells and fish can pick up stimuli:

1. current and direction and movement of water
2. direction the fish swims through the water
3. disturbances in the water flow across the body

EX: fish move in unison=schooling