9 General Senses (Somatic and Visceral Senses) Flashcards
are the awareness of a stimulus
Sensations
involves the interpretation of the sensation and occurs in the CNS.
perception
All senses involve three steps:
- A physical stimulus
- Transformation of stimulus into nerve impulse
- Response to the sensation in the form of a perception or conscious experience of sensation.
signals that originate from the cutaneous areas, muscles, or joints
Somatosensory signals
signals that originate from the internal structures of the body.
viscerosensory signals
Sensory receptors are present in every tissue except in the ____
nervous system
Sensory receptors are classified
into two categories
free nerve endings
encapsulated nerve endings
-receptors with no special
modifications
-Examples are the thermoreceptors and nociceptors.
free nerve endings
-sensory terminals that are ensheathed by a connective tissue capsule.
-example are the mechanoreceptors
encapsulated nerve endings.
Classes of sensory receptors
- Mechanoreceptors
- Chemoreceptors
- Nociceptors
- Thermoreceptors
- Photoreceptors
-detect touch proprioceptive sensation (muscle stretch or contraction), joint position, hearing, and sense of balance.
-These receptors detect distortions in their cell membrane (bending and stretching).
Mechanoreceptors
-function in the sensing of itches, taste, and smell.
-responsible for detecting changes in concentrations of specific chemicals or compounds. These receptors are also responsible for the special senses of taste (gustation) and smell (olfaction). They are responsible for sensing irritating substances on the skin, or nutrients within the GI tract or brain, and carbon dioxide or oxygen levels in our blood.
Chemoreceptors
-detect pain.
-Pain is mediated by this receptor
-These receptors respond to stimuli that can damage tissue.
-Some respond directly to stimuli, and others respond indirectly since they respond to chemicals released by damaged tissue.
Nociceptors
-can sense either warm or cold.
-alter their firing rate as a result of changes in temperature.
Thermoreceptors
sense electromagnetic energy.
Photoreceptors
What are the classification of the receptors based on location
exteroceptors
interoceptors
proprioceptors
*Classified by location
receptors that are sensitive to stimuli outside (external) the body. Located near the surface of the body, they can detect touch, pressure, pain, and temperature, as well as special senses such as smell, taste, vision, and auditory.
Exteroceptors
*Classified by location
receptors that monitor the visceral organs and their function. They detect and monitor chemical, temperature changes, and stretching within viscera.
Interoceptors
*Classified by location
also detect internal signals but are restricted to those receptors in muscles and joints that provide information concerning the position of the bones and muscles.
Proprioceptors
three classes of mechanoreceptors
a. Tactile receptors.
b. Baroreceptors.
c. Proprioceptors.
-responsible for the sensations of touch, pressure, and vibration.
-The two principal mechanoreceptors located in the superficial layer of the skin are the Merkel disc and Meissner’s corpuscles.
-The two mechanoreceptors found in the deep subcutaneous layers of the skin are the Pacinian corpuscles and Ruffini ending.
Tactile receptors.
class of mechanoreceptor that sense change in the walls of distensible organs, including blood vessels, and a portion of the respiratory, digestive, and urinary tracts.
Baroreceptors
class of mechanoreceptor that monitor the position of joints, and the tension in tendons, ligaments, and muscles. These receptors do not adapt, and they continuously send information to the CNS.
Proprioceptors
three groups of proprioceptors:
Muscle spindles.
Golgi tendon organs.
Receptors in the joint capsules
*Proprioceptor
These receptors detect the length of skeletal muscles.
Muscle spindles.
*Proprioceptor
Located at the junction between skeletal muscle and its tendon, this detects the stretch of the tendons. The dendrites of the receptor neurons branch extensively, wrapping around the collagen fibers of the tendon.
Golgi tendon organs.
*Proprioceptor
To monitor the position of the body, joint capsules are innervated with free nerve endings that detect pressure, tension and movement of the joint
Receptors in joint capsules
-are automatic, neural responses to specific stimuli.
-work to preserve homeostasis by making rapid adjustments that do not require conscious activity.
-involve a sensory receptor and a motor response.
Reflex
four steps to a reflex arch:
- Stimulus activates the receptor.
- Information processing.
- Activation of the motor neuron.
- Response of the peripheral effector.
Classification of Reflexes
- Development of reflex.
- Site of information processing.
- Resulting motor response.
*Classification of Reflexes
Innate reflexes these reflexes are involved in the development of a genetically programmed response to specific stimuli. Acquired reflexes may develop later in life as a result of experience.
Development of reflex
*Classification of Reflexes
Spinal reflex is a type of reflex where the processing of information is in the spinal cord. While the processing of information in the brain results in cranial reflexes.
Site of information processing.
*Classification of Reflexes
Reflexes that involve the contraction of skeletal muscle are termed somatic reflexes; those that involve smooth muscle, cardiac muscle, or glands are called visceral reflexes.
Resulting motor response
3 pathways
Mechanoreceptor pathway
Pain Pathway
Thermoreceptor pathway
