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A ______ is a specialized cell or cell process that monitors conditions in the body or the external environment.
The term ______ refers to sensations of temperature, pain, touch, pressure, vibration, and proprioception (body position). ______ receptors are distributed throughout the body
smell (olfaction), taste (gustation), balance (equilibrium), hearing, and vision.
The special senses are ______
a touch receptor is very sensitive to pressure but relatively insensitive to chemical stimuli. This concept is called ______
The area monitored by a single receptor cell is its______ (Figure 18.1). Whenever a sufficiently strong stimulus arrives in the ______, the CNS receives the information. The larger the ______, the poorer our ability to localize a stimulus.
The connection between receptor and cortical neuron is called a ______. Each ______ carries information concerning a specific sensation (touch, pressure, vision, and so forth) from receptors in a specific part of the body.
Some sensory neurons, called ______receptors, are always active The photoreceptors of the eye and various receptors that monitor body position are examples of ______receptors.
receptors normally inactive, become active with change in monitor stimulus. i.e. touch and pressure receptors in skin
Receptors that combine ______receptors and ______ coding convey extremely complicated sensory information; receptors that monitor the positions and movements of joints are in this category.
____ occurs when receptors or sensory neurons alter their levels of activity by responding strongly at first and then declining
a few seconds after exposure to a new smell the sensation fades. this is called ___
. Only about 1 percent of the information provided by afferent fibers reaches the _____and our conscious awareness.
These are examples of _______:
1. Humans do not have receptors for every possible stimulus.
2. Our receptors have characteristic ranges of sensitivity.
3. A stimulus must be interpreted by the CNS. Our perception of a particular stimulus is an interpretation and not always a reality.
___ are common receptors in superficial areas of skin, joint capsules, periostea of bones and around wall of blood vessels. Few are in deep visceral organs.
three types of ______ : (1) receptors sensitive to extremes of temperature, (2) receptors sensitive to mechanical damage, and (3) receptors sensitive to dissolved chemicals, such as those released by injured cells
_____ is caused by deep cuts. This sensations reach the CNS quickly and often trigger somatic responses. Info also sent to primary sensory cortex. Central adaption may reduce pain perception
_____ or burning and aching pain sensations begin later and persist longer then the other pain sensation. Slow pain sensations cause a generalized activation of the reticular formation and thalamus.
___ (receptors) are found in the dermis of the skin, skeletal muscles, liver, hypothalamus
Temperature sensations are conducted along the same pathways that carry ______ sensations. They are sent to the reticular formation, thalamus, & primary sensory cortex
______ are sensitive to stimuli that stretch, compress, twist, or distort their plasmalemmae.
tactile receptors, baroreceptors, proprioceptors
There are three classes of mechanoreceptors______ , ______ , ______
______ detect pressure changes in the walls of blood vessels and in portions of the digestive, reproductive, and urinary tracts
_______ monitor the positions of joints and muscles and are the most complex of the general sensory receptors.
Fine touch, pressure
_______ and _______ receptors provide detailed information about a source of stimulation, including its exact location, shape, size, texture, and movement
Crude touch pressure
_______ and _______ receptors provide poor localization and little additional information about the stimulus.
unencapsulated receptors, encapsulated receptors
six different types of tactile receptors in the skin. They can be subdivided into two groups:
Each _____ communicates with a sensory neuron across a vesicular synapse that involves an expanded nerve terminal known as a tactile disc
In sensitive areas, the dendritic branches penetrate the epidermis and contact _______ in the stratum germinativum.
______cells are sensitive to fine touch and pressure. They are tonically active and extremely sensitive and have narrow receptive fields. Free nerve endings are also associated with hair follicles.
root hair plexus
The free nerve endings of the _______ monitor distortions and movements across the body surface. When the hair is displaced, the movement of the follicle distorts the sensory dendrites and produces action potentials in the afferent fiber.
Touch receptors located within dermal papillae adjacent to the basement membrane of the epidermis; also called Meissner's corpuscles.
Sensory nerve endings that contact special receptors called Merkel cells, located within the deeper layers of the epidermis; also called Merkel's discs.
Large, oval _____ corpuscles (also called Meissner's corpuscles) are found where tactile sensitivities are extremely well developed. They are especially common at the eyelids, lips, fingertips, nipples, and external genitalia.
______ corpuscles detect light touch, movement, and vibration; they adapt to stimulation within a second after contact.
_____ corpuscles, located in the dermis, are also sensitive to pressure and distortion of the skin, but they are tonically active and show little if any adaptation.
_____ are considerably larger encapsulated receptors. layers shield the dendrite from virtually every source of stimulation other than direct pressure.
______ corpuscles respond to deep pressure but are most sensitive to pulsing or vibrating stimuli
Although both _____corpuscles and ____ corpuscles respond to pressure, the ____ corpuscles adapt rapidly while the ____ corpuscles adapt quite slowly
lamellated corpuscles, Ruffini corpuscles
These receptors are scattered throughout the dermis, notably in the fingers, breasts, and external genitalia.
a ______ consists of free nerve endings that branch within the elastic tissues in the wall of a hollow organ, a blood vessel, or the respiratory, digestive, or urinary tract
_____ monitor blood pressure in the walls of major vessels, including the carotid artery (at the carotid sinus) and the aorta (at the aortic sinus).
_________ in the lungs monitor the degree of lung expansion. This information is relayed to the respiratory rhythmicity center, which sets the pace of respiration.
________ in the urinary and digestive tracts trigger a variety of visceral reflexes, such as urination.
________ monitor the position of joints, the tension in tendons and ligaments, and the state of muscular contraction.
Generally, _____ do not adapt to constant stimulation. Muscle spindles are _______ that monitor the length of skeletal muscles
_______ are specialized neurons that can detect small changes in the concentration of specific chemicals or compounds.
In general, _______ respond only to water-soluble and lipid-soluble substances that are dissolved in the surrounding fluid.
____________ neurons are found within the carotid bodies, near the origin of the internal carotid arteries on each side of the neck, and in the aortic bodies between the major branches of the aortic arch.
A group of receptors adjacent to the carotid sinus that are sensitive to changes in the carbon dioxide levels, pH, and oxygen concentrations of the arterial blood.
A specialized neuroepithelium, the _________, which contains the bipolar olfactory receptors, supporting cells, and basal cells (stem cells).
Despite ongoing replacement, the total number of _________ declines with age, and the remaining receptors become less sensitive. As a result, elderly individuals have difficulty detecting odors in low concentrations.
receptors on tongue, ventral to dorsal
Filiform papillae, Fungiform papillae, Circumvallate papillae
Taste buds monitors by 3 cranial nerves:
cranial nerves VII (facial), IX (glossopharyngeal), and X (vagus)
the external ear, the middle ear, and the inner ear
The ear is divided into three anatomical regions: _________
_________ secrete a waxy material, help deny access to foreign objects or insects.
The_________serves to equalize the pressure in the middle ear cavity with external, atmospheric pressure.
Endolymph-filled tubes of the inner ear that enclose the receptors of the inner ear.
Between the bony and membranous labyrinths flows the _________, a liquid whose properties closely resemble those of cerebrospinal fluid.
vestibule the semicircular canals, and the cochlea
The bony labyrinth can be subdivided into the (3)_________
Receptors in the _________and ____provide sensations of gravity and linear acceleration. Those in the semicircular canals are stimulated by rotation of the head.
Opening in the bony labyrinth where the stapes attaches to the membranous wall of the scala vestibuli.
when an elevator starts its downward plunge, we are immediately aware of it because the _________no longer push so forcefully against the surface of the receptor cells.
The two vestibular nuclei
1. integrate the sensory information concerning balance and equilibrium arriving from each side of the head;
2. relay information from the vestibular apparatus to the cerebellum;cerebral cortex
4. send commands to motor nuclei in the brain stem and spinal cord.
Movement of the stapes sets up pressure waves in the _________. These waves distort the cochlear duct and the organ of Corti, stimulating the hair cells.
Before reaching the cerebral cortex and our conscious awareness, ascending auditory sensations synapse in the _________
The _________ of the eye include the eyelids, the superficial epithelium of the eye, and the structures associated with the production, secretion, and removal of tears.
the _________ (Figure 18.19a) produce the thick secretions that contribute to the gritty deposits occasionally found after a good night's sleep.
The epithelium covering the inner surface of the eyelids and the outer surface of the eye is called the _________
(1) a lacrimal gland, (2) superior and inferior lacrimal canaliculi, (3) a lacrimal sac, and (4) a nasolacrimal duct
The lacrimal apparatus of each eye consists of (4) _________
sclera and the cornea
The fibrous tunic, the outermost layer of the eye, consists of the (2) _________
The functions of this layer include (1) providing a route for blood vessels and lymphatics (2) regulating the amount of light entering the eye, (3) secreting and reabsorbing the aqueous humor (4) controlling the shape of the lens,
functions of the vascular tunic
A thickened region of the choroid that encircles the lens of the eye; it includes the ciliary muscle and the ciliary processes that support the suspensory ligaments of the lens.
_________ are the only cells in the retina that generate action potentials to the brain.
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