Sensory Organs: Mechanoreceptors and Chemoreceptors

Flashcards covering key concepts of sensory organs, specifically mechanoreceptors and chemoreceptors based on lecture notes.

What are the five functional types of sensory receptors?

Mechanoreceptors, Thermoreceptors, Nociceptors, Photoreceptors, Chemoreceptors.

What do mechanoreceptors detect?

Mechanical stimulation.

Name three types of encapsulated end organs.

Pacinian corpuscles, Meissner’s corpuscles, Ruffini’s end organs.

What is a key function of muscle spindles?

They detect muscle stretch and monitor muscle tone.

What do Golgi tendon organs sense?

Muscle tension.

How are sensory receptors classified?

By functional categories and morphology.

What role do sensory receptors play in the nervous system?

They convert stimuli into afferent nerve impulses.

What is the main role of the eye in the sensory system?

It acts as an optic sensory organ.

What are the major senses that contribute to sensory information?

Vision, Auditory, Taste, Smell, and various general senses.

What types of receptors detect changes in temperature?

Thermoreceptors.

How do nociceptors function?

They are free nerve endings that detect pain through stimuli like pinching, tearing, and burning.

What are photoreceptors responsible for?

They are responsible for detecting light and contributing to vision, specifically rods and cones.

What do chemoreceptors detect?

Chemicals related to the senses of taste and smell.

Describe the structure of a Pacinian corpuscle.

It has a central non-myelinated nerve fiber surrounded by concentric layers of connective tissue.

What does the Ruffini ending detect?

It detects pressure and continuous deformation.

Where are Meissner’s corpuscles primarily located?

In the dermal papillae of fingertips and other sensitive skin areas.

What is the function of Merkel discs?

They detect light touch sensations.

What sensory function do muscle spindles fulfill?

They provide information about muscle length and tone.

What structure helps in light touch detection in the skin?

Merkel cells.

What are the four primary sensations of taste?

Sour, salty, sweet, and bitter.

What are the estimated number of taste buds in humans?

Approximately 3,000 to 5,000 taste buds.

How is taste perceived?

Taste buds are stimulated by chemicals in food.

What kind of receptors are involved in the olfactory sense?

Olfactory receptor cells located in the olfactory epithelium.

What is the role of sustentacular cells in the olfactory membrane?

They provide mechanical and physiological support.

How many olfactory receptor cells are estimated to exist in humans?

About 100 million olfactory receptor cells.

Describe how olfactory receptor cells are structured.

They are bipolar neurons with a dendritic process extending from the soma.

What is adaptation in sensory receptors?

The decreased response to a constant stimulus.

What compounds do taste receptors primarily respond to?

Food molecules dissolved in saliva.

What happens when a tastant binds to a taste receptor?

It triggers a signal transduction process involving G proteins that leads to depolarization.

What is one characteristic of Golgi tendon organs?

They continually respond to tension in muscles and tendons.

What does the olfactory process involve when detecting odors?

It involves cilia reacting to chemical components in the air.

Which nerve fibers innervate taste buds?

Up to 50 non-myelinated nerve fibers innervate each taste bud.

What is a key functional aspect of chemoreceptors?

They detect chemicals that influence taste and smell.

What is the measurement of the surface area covered by the olfactory membrane in each nostril?

2.4 cm^2.

What phenomenon can affect the perception of taste during illness?

Loss of taste can happen due to colds or allergies affecting olfaction.

What is the process through which olfactory signals are transmitted to the brain?

Sensory neurons' axons pass through the cribiform plate into the olfactory bulb.

What two types of cells are present in a taste bud?

Gustatory cells and sustentacular cells.

How do gustatory cells function within taste buds?

They have microvilli that act as taste receptors.

What do the cilia of olfactory receptor cells do?

They project outward and function as chemoreceptors.

What factors influence the adaptation rate of olfactory receptors?

Olfactory receptors adapt very rapidly, often within seconds.

What happens to sensory responses when there is a constant stimulus?

All receptors adapt, resulting in a reduced response.

How are different types of taste buds characterized?

By their size, shape, and adaptability to stimuli.

How does the structure of Ruffini's endings assist in their function?

They are loosely encapsulated and respond to continuous deformation.

What is one significant characteristic of Pacinian corpuscles?

They are sensitive to strong or rapid movement of tissues.

What type of mechanoreceptors are located in the Organ of Corti?

Hair cells that detect sound.

How do the olfactory receptors allow for the detection of odor?

Through the activation of signal pathways leading to action potentials in the sensory neurons.

Why is the structure of the olfactory bulb significant?

It processes olfactory information before transmitting it to the brain.

What can be concluded about the role of chemoreceptors?

They are fundamental in facilitating taste and smell detection.