Sensory System Flashcards
The body system that allows us to experience the world (sight, vision, touch, taste, smell, etc.).
Sensory system
The body system that acts as a warning system.
Sensory system
The body system that allows us to keep track of what is happening within our bodies. For example, when the stomach fills with food, information is carried to the central nervous system (CNS). In response to this information, the stomach is prompted to digest the food.
Sensory system
Transmits information to the CNS.
Sensory neuron
A specialized area of a sensory neuron that detects a specific stimulus.
Receptor
Receptors stimulated by changes in the chemicals such as hydrogen ion (H+), calcium, and food.
Chemoreceptors
Receptors stimulated by tissue damage or distention.
Nociceptors (noh-see-sep-tors) / pain receptors
Receptors stimulated by changes in temperature.
Thermoreceptors
Receptors stimulated by changes in pressure or movements of body fluids.
Mechanoreceptors
Receptors stimulated by light.
Photoreceptors
Hearing and equilibrium receptor.
Mechanoreceptors
Taste and smell receptor.
Chemoreceptors
The conscious or unconscious awareness of incoming sensory information.
Sensation
The conscious awareness of a sensation. Yelling, “Ouch, that knife is sharp,” for example, indicates that you have become aware of a painful stimulus and what caused it.
Perception
Sensation has ___ components.
4
Light is an example of this sensory component for the sense of sight. In the absence of light, you cannot see.
Stimulus
Light waves are an example of this sensory component for the sense of sight as photoreceptors in the eye produce a nerve impulse.
Receptor
The nerve impulse is conducted by this sensory nerve to the occipital lobe of the brain.
Optic nerve
For the sense of sight, the sensory information is interpreted as sight in this special area of the brain.
Occipital lobe
True or false: sensation is experienced by the brain and not by the sensory receptor.
True
Stimulates a part of your brain.
Sensory receptors
Two important characteristics of sensation.
Projection and adaptation
Describes the process whereby the brain, after receiving a sensation, refers that sensation back to its source.
Projection
You see with your eyes, hear with your ears, and feel pain in your injured finger because the cortex of your brain receives the sensation and ___ it back to its source.
projects
Answers the question, “if pain is experienced by the brain, why does my injured finger hurt?
Projection
The experience of ‘phantom limb pain’ is example this.
Projection
Illustrated by the sense of smell: when you enter a room with a strong odor, the odor at first seems overwhelming. After a short time, however, the odor becomes less noticeable. The sensory receptors in the nose have ___. When they are continuously stimulated, these receptors send fewer signals to the area of the brain that interprets sensory information as smell.
adapted
An excellent example of this is the advertisement for an air freshener that states, “He’s gone nose-blind.”
Adaption
True or false: pain receptors do not adapt, whereas the receptors for smell adapt rapidly.
True
True or false: generally, receptors that regulate homeostatic mechanisms adapt very slowly or not at all.
True
There are ___ groups of senses.
2
The receptors of these two senses are widely distributed throughout the body.
General senses / somatic senses
Localized within a particular organ in the head.
Special senses
Includes taste, smell, sight, hearing, and balance.
Special senses
The Four Components of Sensation.
Includes pain, touch, pressure, temperature, and proprioception.
General senses
Receptors for these senses are widely distributed and are found in the skin, muscles, joints, and viscera.
General senses
General Senses.
Consist of free nerve endings that are stimulated by tissue damage.
Nociceptors / pain receptors
These receptors do not adapt and may continue to send signals after the stimulus has been removed.
Nociceptors / pain receptors
These receptors are widely distributed throughout the skin and other internal tissues.
Nociceptors / pain receptors
True or false: the nervous tissue of the brain lacks pain receptors.
True
Serves a protective function.
Pain
True or false: tissues surrounding the brain, such as the meninges and the blood vessels, contain pain receptors (you can feel a headache).
True
Being unpleasant, pain motivates the person to ___ its cause. Failure of the pain receptors to ___ is also protective. For example, if a person complains of right-lower-quadrant (RLQ) abdominal pain, the pain serves as a valuable clue to what is wrong.
remove
adapt
Some patients are at risk because of a diminution or alteration in the sensation of ___. Persons with diabetes mellitus, for example, often develop nerve damage in their legs and feet; the nerve damage is called diabetic ___. Because of the distortion in the sensation of pain, diabetic persons may ignore the discomfort of ill-fitting shoes and may develop blisters on their feet. The blistered site continues to expand and eventually becomes infected and gangrenous, requiring amputation. This is a common experience among diabetic persons and is the reason for meticulous attention to their foot care.
pain
neuropathy
___ injury promotes the release of chemicals that stimulate pain receptors.
Tissue
A deficiency of ___ stimulates pain receptors. For example, if the blood supply to an internal organ is diminished—a condition called ischemia—the tissue is deprived of ___ and the person experiences pain. The pain of a heart attack is caused in part by ___ deprivation experienced by the cardiac muscle. Restoration of blood flow and improved ___ of the heart muscle is pain-relieving.
oxygen x3
oxygenation
Pain may be experienced when tissues are ___ or deformed. The stimulus is mechanical distortion rather than chemical. For example, if the intestine becomes distended, the person will often experience severe cramping pain.
stretched
True or false: pain originating in the heart (visceral pain) is often experienced in the shoulder and left arm.
True
Pain feeling as if it were coming from an area other than the site where it originates.
Referred pain
Its occurrence is the result of shared sensory nerve pathways. The nerve pathways that carry information from the heart are the same pathways that carry information from the shoulder and left arm. As a result, the brain interprets heart pain as shoulder and arm pain.
Referred pain
Pain impulses for most of the body travel up the spinal cord in a sensory nerve tract called the ___ tract. The information is then transmitted to the ___, where the person first becomes aware of the pain, and then to the ___ lobe.
spinothalamic
thalamus
parietal
Can identify the source of the pain and judge its intensity and other characteristics.
Parietal lobe
The receptors for touch and pressure.
Mechanoreceptors
They respond to forces that press, move, or deform tissue.
Mechanoreceptors
Also called tactile receptors.
Touch receptors
Are found mostly in the skin; they allow us to feel, for example, a cat’s soft fur.
Touch receptors
They are particularly numerous in the lips and tips of the fingers as well as in the toes, tongue, penis, and clitoris.
Touch receptors
True or false: fingers have the highest concentration of touch receptors.
True
True or false: receptors for heavy pressure are located in the skin, subcutaneous tissue, and the deep tissue.
True
The first sensory system to develop in the fetus and is essential to its growth and development.
Touch
No touch results in this syndrome.
Failure to thrive syndrome
The receptors for temperature.
Thermoreceptors
The are two types of thermoreceptors are ___ and ___ receptors.
heat
cold
Found on free nerve endings and are scattered widely throughout the body.
Thermoreceptors
The ___ receptors are stimulated at between 50°F and 76°F (10°C and 25°C).
cold
___ receptors are stimulated between 76°F and 112°F (25°C and 45°C).
Heat
At both ends (extremes) of the temperature scale, ___ receptors are stimulated, producing a freezing or burning sensation.
pain
Both heat and cold thermoreceptors display ___, so that the sensation of heat or cold fades rapidly. Immerse your hand in warm water and note how quickly the feeling of warmth disappears, even though the temperature of the water has not decreased. Your heat receptors have ___.
adaption
adapted
Remember that ___ receptors do not adapt. If you placed your hand in boiling water, you would feel intense continuous ___ prompting you to quickly remove it.
pain x2
Sensory information regarding temperature is sent to the ___ lobe.
parietal
The sense of orientation or position.
Proprioception (proh-pree-oh-ception)
This sense allows you to locate a body part without looking at it. In other words, if you closed your eyes, you would still be able locate your arm in space; you do not have to see your arm to know that it is raised over your head.
Proprioception
Plays an important role in maintaining posture and coordinating body movements.
Proprioception
The receptors for proprioception, called ___, are located in muscles, tendons, and joints. ___ are also found in the inner ear, where they function in balance or equilibrium. The ___, which plays a major role in coordinating skeletal muscle activity, receives sensory information from these receptors. Sensory information regarding movement and position is also sent to the ___ lobe of the cerebrum.
proprioceptors
Proprioceptors
cerebellum
parietal
Includes smell, taste, sight, hearing, and balance.
Special senses
The receptors for the special senses are located here.
Head
The sense of smell is also called:
olfaction.
Associated with sensory structures located in the upper nose.
Olfaction
These receptors are very sensitive and classified as chemoreceptors, meaning that they are stimulated by chemicals that dissolve in the moisture of the nasal tissue.
Olfactory (ol-fak-tor-ee)
Once the olfactory receptors have been stimulated, the sensory impulses travel along this.
Olfactory nerve (CN I)
The sensory information is eventually interpreted as smell within the ___ area of the ___ and ___ lobes.
olfactory
temporal
frontal
Located high in the nose, where the air circulation is poor.
Olfactory receptors
Sense of smell.
True or false: your sense of smell is a valuable diagnostic tool. You can smell the acetone breath of a person in diabetic ketoacidosis and the putrid odor of an infected wound.
True
(CN: I)
Crainial Nerve: olfactory nerve
The sense of taste is also called:
gustatory (gus-tah-tor-ee) sense or gustation.
Special organs of taste.
Taste buds
Located primarily on the tongue and are classified as chemoreceptors, meaning that they are activated by the chemicals in our food.
Taste receptors
A small number of these are also located on the palate, tonsils, and throat.
Taste buds
Salty, sweet, sour, and bitter.
Four basic taste sensations
Sweet and salty substances are most sensitive in this particular area of the tongue.
Tip
Sour sensations are found primarily on this particular area of the tongue.
Sides
Bitter substances are most strongly tasted on this part of the tongue.
Back
When the taste receptors are stimulated, the taste impulses travel along three cranial nerves (___, ___, and ___ nerves) to various parts of the brain, eventually arriving in the ___ and ___ lobes of the ___ cortex.
facial
glossopharyngeal
vagus
temporal
frontal
cerebral
Sense of Taste.
(CN: VII, IX, and X)
Cranial Nerves: facial, glossopharyngeal, and vagus.
The organs of vision.
Eyes
They contain visual receptors.
Eyes
Assist the eyes in their function and protect them from injury.
Visual accessory organs
The study of the eye and its function is called:
ophthalmology.
The sense of sight =
vision.
Include the eyebrows, eyelids, conjunctiva, eyelashes, lacrimal apparatus, and extrinsic eye muscles.
Visual accessory organs
They keep perspiration out of the eyes and shade the eyes from glaring sunlight.
Eyebrows
Eyelids =
palpebrae.
They prevent the entrance of foreign objects and wash tears over the surface of the eye.
Eyelids
The upper and lower eyelids meet at the corners of the eyes. The corners are called the medial (inner) ___ and lateral (outer) ___.
canthus x2
Composed of four layers: skin, skeletal muscle (orbicularis oculi), connective tissue, and an inner lining called the conjunctiva.
Eyelids
The margin of these contain tarsal or meibomian glands, special types of sebaceous glands that secrete an oil that coats the surface of the eye and reduces evaporation of the tears.
Eyelids
Open and close the eyelids (general).
Skeletal muscles
Attached to the eyelid and the upper bony orbit; contraction of this muscle opens the eye.
Levator palpebrae superioris muscle
Le-vay-ter pelp-per-bry super-ryer-us
Contraction of this closes the eye.
Orbicularis oculi muscle
Or-bic-you-lare-us
Line the edges of the eyelid and help to trap dust.
Eyelashes
A thin mucous membrane that lines the inner surface of the eyelids. It also folds back to cover a portion of the sclera on the anterior surface of the eyeball.
Conjunctiva (kon-junk-tie-vah)
True or false: the conjunctiva does not cover the cornea.
True
Secretes a thin mucous film that moistens the surface of the eye.
Conjunctiva
The meeting place of the white of the eye with the cornea, which overlies the colored iris.
Limbus
Very vascular, meaning that it has many blood vessels.
Conjunctiva
(A) Visual accessory organs and lacrimal apparatus. (B) Flow of tears from the lacrimal gland to the nasolacrimal duct.
Concerned with the secretion, distribution, and drainage of tears.
Lacrimal (lak-ri-mal) apparatus
(A) Structure of the eyeball. (B) Cavities and fluids. (C) Flow of aqueous humor from the ciliary body to the canal of Schlemm (arrow).
Special Senses Table.
(A) Extrinsic muscles: four rectus muscles and two oblique muscles (only five are shown). (B) Intrinsic eye muscles: iris (circular and radial muscles).
Pathway of Light: from Cornea to Photoreceptors in the Retina.
Refraction.(A) Path that the light waves travel (without lens). (B) Refraction of the first and third light waves (with lens).
Visual Pathway. (A) From retina to primary visual cortex (occipital lobe). Note the optic chiasm and the pituitary gland (behind the optic chiasm). (B) From retina to primary visual cortex (occipital lobe).
Three divisions of the ear: external, middle, and inner. Structures within the ear.
Inner Ear.(A) The receptors for balance. (B) The receptors for hearing (organ of Corti). (C) Structures of the inner ear.
