Module 06: Special Senses Flashcards
This are the means by which the brain receives information about the environment and the body.
Senses
This is the process initiated by stimulating sensory receptors.
Sensation
This pertains to the conscious awareness of those stimuli received by the sensory neurons.
Perception
How does the brain receive stimuli?
Sensory receptors respond to stimuli by generating action potentials that are propagated to the spinal cord the brain. Perception results when action potentials reach the cerebral cortex.
What are the characteristics of a sensation?
(1) Projection - area
(2) Intensity - degree
(3) Contrast - effect of a previous sensation to the current one
(4) Adaptation - becoming aware of continuing stimulus
(5) After Image - the sensation remains in the consciousness
This characteristic of the sensation pertains to how the sensation comes from the area where the receptors where stimulated, even though it is the brain that truly feels the sensation.
Projection
This characteristic of sensation pertains to the degree to which the sensation is felt; a strong stimulus affects more receptors and more impulses are sent to the brain.
intensity
This characteristic of sensation pertains to the effect of the previous or simultaneous sensation on a current sensation as the brain compares them.
Contrast
This characteristic of the brain pertains on becoming aware of the continuing stimulus. If the stimulus remains constant, there is no change for the receptors to detect.
Adaptation
This characteristic of the sensation pertains as to how the sensation remains in the consciousness after the stimulus has stopped.
After image
What are the two basic groups of senses?
(1) General senses
(2) Specific Senses
These senses have receptors distributed over a large part of the body that can sense touch, pressure, pain, temperature, and itch.
General Senses
These forms of general senses provide information about body and environment
Somatic Senses
These form of general senses provide information about internal organs, primarily involving pain and pressure.
Visceral Senses
These receptors are more specialized in structure and are localized to specific parts of the body. These include (1) Smell (olfaction), (2) taste, (3) vision, (4) hearing, and (5) Balance
Special Senses
What are the general senses?
(1) Touch
(2) Pressure
(3) Pain
(4) temperature
(5) Vibration
(6) Itch
(7) Proprioception
This sense pertains to the sense of movement and the position of the body.
Proprioception
These are sensory nerve endings or specialized cells respond to stimuli by developing action potentials.
Sensory receptors
These respond to mechanical stimuli , such as the bending or stretching of receptors (these detect movement).
Mechanoreceptors
These respond to chemicals. For example odor molecules binding to chemoreceptors, allowing us to perceive smells.
Chemoreceptors
These respond to light
Photoreceptors
These respond to temperature changes.
Thermoreceptors
These respond to stimuli that result in the sensation of pain
Nociceptors
These are the simples and most common type of sensory receptors and is relatively unspecialized neuronal branches to dendrites and is distributed to almost all parts of the body.
Free nerve endings
Free nerve endings can detect what?
(1) painful stimuli
(2) temperature
(3) itch
(4) movement
These are receptors that respond to decreasing temperatures but stop responding at temperatures below 12 degrees C (54F)
Cold receptors
These are receptors that respond to increasing temperatures but stop responding at temperatures above 47 degrees C (117F)
Warm receptors
In what temperature levels are pain receptors stimulated?
below 12 degrees Celsius or above 47 degrees Celsius
These are small, superficial nerve endings involved in detecting light touch and superficial pressure.
Merkel’s disk
These are associated with hairs and are also involved in detecting light touch.
Hair follicle receptors
These are very sensitive but not very discriminative, meaning that the point being touched cannot solely be precisely located.
Light touch receptors
These are receptors for fine, discriminative touch, just located deep into the epidermis, These receptors are very specific in localizing tactile sensations.
Meissner corpuscle
These are deeper tactile receptors and play an important role in detecting continuous pressure in the skin.
Ruffini corpuscle
These are the deepest receptors and are associated with tendons and joints. These receptors relay information concerning deep pressure, vibration, and position (proprioreception).
Pacinian corpuscle
Why is our proprioreception important?
(1) maintain postures
(2) perform daily bodily movements
How are proprioceptive information conveyed?
not only to our cerebrum (conscious awareness of our body position), but also different parts like the cerebellum
This enables us to maintain an upright position, even if our body is in an uneven ground.
righting reflex
This is characterized as an unpleasant perceptual and emotional experience. It can either be localized or diffused.
Pain
This kind of pain involves sharp, pricking, or cutting pain resulting from rapid conducted action potentials.
Localized pain
This kind of pain involves burning or aching paid resulting from action potentials that are propagated more slowly.
Diffusing pain
These are highly localized as a result of the simultaneous simulation of pain receptors and tactile receptors
Superficial pain sensations
These are not highly localized because of the absence of tactile receptors in the deeper structures. And are usually perceived as diffused pain.
Deep or visceral pain
This suppresses action potentials from pain receptors in local areas of the body through the injection of chemical anesthetics near a sensory receptor or nerve.
Local anesthesia
This is a treatment where chemical anesthetics affect reticular activating system or reticular formation. It is also associated with the loss of consciousness.
General anesthesia
How are pain sensations be influenced by inherent control?
Sensory neuros associated with tactile receptors are linked to the pain sensory pathway to the CNS. Therefore, stimulation of these tactile receptors can result to decreased perception of pain.
This is perceived to originate in a region of the body that it is not the source of the pain stimulus. This is also a visceral pain that is felt as a cutaneous pain.
Referred pain
When is referred pain felt?
Felt when internal organs are damages or inflamed
What causes referred pain?
When sensory neurons from the superficial area and the neurons of the source pain (visceral area) converge onto the same ascending neurons of the spinal cord
In terms of referred pain, this is referred to as the most superficial structures innervated, such as the skin.
painful sensation
What are the areas of referred pain?
(1) Liver and gallbladder
(2) Esophagus
(3) Kidney
(4) Appendix
(6) Urinary Bladder
(7) Lung and diaphragm
(8) Heart
(9) Stomach
(10) Colon
(11) Ureter
This is defined as the sense of smell and occurs as a response to airborne molecules.
Olfaction
These are airborne molecules to which the sense of olfaction respond to.
Odorants
These are bipolar neurons within the olfactory epithelium.
Olfactory Neurons
These lines the superior part of the nasal cavity.
Olfactory Epithelium
These are part of the olfactory neurons which extends in the epithelial surface.
Dendrites
These are the ends of the dendrites, which are long that lie in a thin mucous film located on the epithelial surface.
Cilia
This keeps the nasal epithelium moist, traps, and dissolves airborne molecules, and facilitates the removal of molecules and particles from the nasal epithelium.
Mucus
What happens to airborne odorants in the olfactory>
Airborne odorants become dissolved by the mucus on the surface of the epithelium and binds to the receptor molecules on the membranes of the specialized cilia. The binding of the odorant to the receptor then initiates action potentials that are conducted to the olfactory cortex of the cerebrum by the sensory neurons.
How much estimated functional olfactory neurons are found in the body?
400
How much estimated smells can be detected by the olfactory?
10,000
What happens to a receptor when it binds to an odorant?
it becomes desensitized and does not respond to another odor molecule for some time, which helps in the adaptation to a particular color (threshold for detecting odors is small=few olfactory neurons can initiate an action potential)
These carry action potentials from the olfactory neurons to the cerebrum that allow for perception and interpretation of stimuli.
Neuronal pathways of olfaction
These from the olfactory neurons form the olfactory nerves (cranial nerve 1), which pass through the foramina of the cribriform plate and enter the olfactory nerve.
Axons
This is where the new action potentials relayed from the synapsis of olfactory neurons and interneurons pass to the brain.
Olfactory Tracts
This is where the axons pass through and is known to be beside the foramina of the cribriform plate.
Olfactory bulb
Each olfactory tract terminates in an area of the brain called the _________________, which is located in the frontal and temporal lobes. And is involved in both the conscious perception of smell and the visceral and emotional reactions that are often linked to odors.
Olfactory Cortex
How is the olfaction relayed?
It is relayed through the cerebral cortex first and not the thalamus, this is the reflection of the older and more primitive origin of the olfactory cortex.
These are found in the olfactory cortex and olfactory bulb that tends to inhibit transmission of action potentials resulting from prolonged exposure to given odorants.
Feedback loops
How does the feedback help in adaptation?
The feedback plus the temporary decreased activity at the level of the receptors results in adaptation.
Explain the olfaction process
(1) Nasal cavity contains a thin film of mucous where odors become dissolved
(2) Olfactory neurons are located in the mucous. Dendrites of olfactory neurons are enlarged and contain cilia
(3) The dendrites pick up odor, depolarize and carry odor to axons in the olfactory bulb
(4) frontal and temporal lobes process odors
These are sensory structures that detect taste stimuli. These are also characterized as oval structures that are located on the surface of certain papillae (nipples).
Taste buds
These are enlargements on the surface of the tongue that contain the taste buds.
papillae (nipples).
This is known as the root of the mouth
Palate
What are the two cells that form the taste bud?
(1) Special epithelial cells
(2) 40 taste cells (interior portion)
These form the exterior supporting capsule of each taste bud.
Special epithelial cells
These are found in taste cells and are characterized as hair like processes that extend through a tiny opening in the surrounding stratified epithelium (taste pore)
Taste Hairs
This is known as the tiny opening in the surrounding stratified epithelium.
Taste Pore
How does taste sensation initiate action potentials?
Dissolved molecules or ions bind to the receptors on the taste hair and initiate action potentials, which sensory neurons carry to the insula of the cerebral cortex.
Taste sensations are divided into five basic types which are:
(1) sour
(2) salty
(3) bitter
(4) sweet
(5) umami
How does heat damages affect epithelial tissues?
Heat damage can cause injury to the tongue epithelial tissue or even death of the cells, including taste cells in the taste buds. If the epithelial cells are only damages, sensation can return within a few hours to a few days, but if they die, it takes about 2 weeks to be replaced.
What are the three cranial nerves that carry taste sensations to the brain?
(1) Facial nerve (VII)
(2) Glossopharyngeal nerve (IX)
(3) Vagus nerve (X)
This cranial nerve transmits taste sensations from the anterior two-thirds of the tongue.
Facial nerve (VII)
This cranial nerve carries taste sensation from the posterior one-thirds of the tongue.
Glossopharyngeal nerve (IX)
This cranial nerve carries taste sensations from the root of the tongue.
Vagus nerve (X)
How are taste sensations carried to the brain?
Taste buds to the tractus solitarius of the medulla oblangata. Axons from in the three cranial nerves synapse in the gustatory portion of the brainstem nuclei. Axons from the neurons in these brainstem nuclei extend and synapse with the interneurons in the thalamus. Axons from the neurons in the thalamus project to the taste area in the insula of the cerebrum.
What does the visual system include?
(1) eyes
(2) accessory structures
(3) sensory neurons
These are bony cavities that houses the eyes
Orbits
These includes information about light and dark, movement and color. It begins as actions potentials originating from the eyes.
Visual Input
These protects, lubricates, and moves the eyes. They include the eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles.
Accessory Structures
These protect the eyes by preventing perspiration from running down the forehead into the eyes, causing irritation. They also help shade the eyes from direct sunlight.
Eyebrows
These are associated with lashes and protects the eyes from foreign objects.
Eyelids
This refers to when an object suddenly approaches the eye, the eyelids protect the eye by closing then opening quite rapidly.
Blink reflex
How often does blinking occur?
20 times per minute (which lubricates the eyes by spreading tears over the surface)
This is a thin, transparent mucous membrane covering the inner surface of the eyelids and the anterior surface of the eye.
Conjunctiva
These primarily help in lubricating the eyes.
Conjunctive secretions
This is inflammation of the conjunctiva.
Conjunctivitis
This consists of a lacrimal gland situated in the superior lateral corner of the orbit and a nasolacrimal duct and associated in the inferior medial corner of the orbit.
Lacrimal Apparatus
This is the structure in eye that excretes fluid that we call tears, which passes through the anterior surface of the eye.
Lacrimal gland