Holes Anatomy ch 10 Senses Assesment

Explain how the senses of smell and taste function together to create the perception of the flavors of foods.

Both olfactory and taste receptors are sensitive to chemical sensations. Because of this, we smell the food at the same time we taste it. Often, it is impossible to tell whether the sensation is mostly from the smell of a food or from the actual taste.

Match each sensory receptor to the type of stimulus to which it is likely to respond: the smell of roses

Chemoreceptor

Match each sensory receptor to the type of stimulus to which it is likely to respond: a change in blood pressure

Mechanoreceptor

Trace each step in the pathway from the spiral organ to the interpreting centers of the cerebrum.

Once the sound is converted into a nerve impulse at the organ of Corti, it travels along the cochlear branch of the vestibulocochlear nerve to the auditory cortex of the temporal lobe of the brain. On the way, some of the nerve branches cross over, so that impulses from both ears will be interpreted by both sides of the brain.

Match each sensory receptor to the type of stimulus to which it is likely to respond: an infected tooth

Pain receptor

Match each sensory receptor to the type of stimulus to which it is likely to respond: approaching headlights

Photoreceptor

Explain the difference between a sensation and a perception.

The raw form in which receptors send information to the brain is called sensation. The way our brains interpret this information is called perception.

Which two of the following are part of the olfactory organs? a. olfactory receptor cells b. columnar epithelial cells in the nasal mucosa c. the brain d. the eyes

a. olfactory receptors and b. columnar epithelial cells in the nasal mucosa

Explain the basis of fading senses of smell and taste with aging.

The senses of smell and taste may begin to diminish due to anosmia, a decrease or loss of olfactory receptors.

Trace each step in the pathway from the external acoustic meatus to hearing receptors.

The sound waves enter the external auditory meatus. Changes of wave pressures cause the eardrum to reproduce the vibrations coming from the sound wave source. Auditory ossicles amplify and transmit the vibrations to the end of the stapes. Movement of the stapes at the oval window transmits vibrations to the perilymph in the scala vestibuli. Vibrations pass through the vestibular membrane and enter the endolymph of the cochlear duct. Different frequencies in the endolymph stimulate different sets of receptor cells.

Identify the parts of the tympanic reflex, explain how they work, and explain the importance of this reflex.

The tympanic reflex consists of two skeletal muscles associated with the middle ear that are controlled involuntarily. The reflex is elicited by long, external sounds causing the bridge of the ossicles to become more rigid, reducing its effectiveness in transmitting vibrations to the inner ear. The tympanic reflex reduces pressure from loud sounds that might otherwise damage the hearing receptors.

Match each sensory receptor to the type of stimulus to which it is likely to respond: a cool breeze

Thermoreceptor

Match the ear area with the associated structure: Middle ear

auditory ossicles

List three causes of hearing loss associated with aging.

1. Cumulative damage to the sensitive hair cells of the spiral organ in the inner ear. 2. Degeneration or failure of nerve pathways to the brain. 3. Tinnitus, a ringing or raring in the ears.

Contrast the nerve pathways involved in the production of acute and chronic pain.

Acute pain fibers conduct nerve impulses rapidly, at velocities up to 30 meters per second. These impulses are associated with the sensation of sharp pain, which typically seems to originate in a local area of skin. This type of pain seldom continues after the pain-producing stimulus stops. Chronic pain fibers conduct impulses more slowly than acute pain fibers, at velocities up to 2 meters per second. These impulses cause dull, aching pain sensations that are difficult to pinpoint. Chronic pain is felt in deeper tissues, as well as in the skin.

Trace each step in the pathway from an olfactory receptor to the interpreting center of the cerebrum.

An olfactory receptor that has been stimulated causes nerve impulses to be triggered and travel along the axons of the receptor cells that are the fibers of the olfactory nerves. These fibers lead to neurons located in the olfactory bulbs that lie on either side of the crista galli of the ethmoid bone. In the olfactory bulbs, the impulses are analyzed and additional impulses are located within the temporal lobes and at the base of the frontal lobes just anterior to the hypothalamus.

Explain the projection of a sensation.

At the time when a sensation is created, the cerebral cortex causes the feeling to come from the stimulated receptors. It is called projection because the brain projects the sensation back to its apparent source.

List the factors that are likely to stimulate visceral pain receptors.

Factors that stimulate visceral pain receptors include: widespread stimulation of visceral tissues, stimulation of mechanoreceptors, and decrease blood flow accompanied by lower oxygen concentration and accumulation of pain-stimulating chemicals.

Explain the difference between a general sense and a special sense.

General senses are those with receptors widely distributed throughout the body, including the skin, various organs, and joints. Special senses have more specialized receptors and are confined to structures in the head, such as the eyes and ears.

Compare pain receptors with the other types of somatic receptors.

Most pain receptors can react to more than one type of change. In other words, pain receptors may react directly to mechanical damage, chemical changes, by-products of metabolism, ischemia, hypoxia, or stimulation of other receptors such as mechanoreceptor. So, pain receptors are not usually limited to the specific types of stimulation that other somatic receptors are.

Distinguish between muscle spindles and Golgi tendon organs.

Muscle spindles are found in skeletal muscles near their junctions with tendons. Each spindle contains one or more modified skeletal muscle fibers enclosed in connective muscle tissue. Each fiber has a non-striated region with the end of a sensory nerve fiber wrapped around it. Golgi tendon organs are found in the tendons close to their muscle attachment and each is connected to a set of muscle fibers and innervated by a sensory neuron.

Explain how neuropeptides relieve pain.

Neuropeptides called enkephalins and monoamine serotonin inhibit pain sensations by blocking the impulses from the presynaptic nerve fibers in the spinal cord. Enkephalins suppress both acute and chronic pain impulses much like morphine does. Serotonin stimulates other neurons to release enkephalins. Another group of neuropeptides are the endorphins. They are found in the pituitary gland, hypothalamus, and other regions of the nervous system. These act as pain suppressors with a morphine-like action.

Define referred pain, and provide an example.

Referred pain is a phenomenon that occurs when the pain feels as if it is coming from some part of the body other than the part being stimulated. An example would be pain that originates from the heart may actually be felt in the left shoulder or left arm.

Define sensory adaptation.

Sensory adaptation occurs when sensory receptors are subjected to continuous stimulation. As the receptors adapt, impulses leave them at decreasing rates, until finally these receptors may completely fail to send signals. Once receptors have adapted, impulses can be triggered only if the strength of the stimulus is unchanged.

Trace each step in the pathway of a taste receptor to the interpreting center of the cerebrum.

Sensory impulses from the taste receptors located in various regions of the tongue travel on fibers of the facial, glossopharyngeal, and vagus nerves into the medulla oblongata. From there, the impulses ascend to the thalamus and are directed to the gustatory cortex, which is located in the parietal lobe of the cerebrum along a deep portion of the lateral sulcus.

Explain how sensory receptors stimulate sensory impulses.

Sensory receptors can either be nerve endings or special cells located next to them. Stimulation causes local changes in their membrane potentials and generates a graded electrical current showing the intensity of the stimulation.

Explain how general senses can be grouped.

Somatic senses can be divided into three groups: Exteroceptive senses—these senses are associated with changes at the body surface. Proprioceptive senses—these senses are associated with changes in muscle, tendons, and in body positions. Visceroceptive senses—these senses are associated with changes in the viscera.

Name the five primary taste sensations and indicate a specific stimulus for each.

Sweet as produced by table sugar. These receptors are most plentiful near the tip of the tongue. Sour as produced by vinegar. These receptors occur primarily along the margins of the tongue. Salty as produced by table salt. These receptors are most abundant in the tip and the upper front part of the tongue. Bitter as produced by caffeine or quinine. These receptors are located toward the back of the tongue. Umami as produced by the flavor enhancer monosodium glutamate. It is described as savory, pungent, and meaty.

Describe the functions of the auditory ossicles.

The bones form a bridge connecting the tympanic membrane to the inner ear. They function to transmit vibrations between these parts.

Explain how a hearing receptor stimulates a sensory neuron.

The cell releases a neurotransmitter that stimulates the nearby sensory nerve fibers, and they transmit impulses along the cochlear branch of the vestibulocochlear nerve to the auditory cortex of the temporal lobe of the brain.

Describe the cochlea and its function.

The cochlea contains a bony core and a thin bony shelf that winds around the core like the threads of a screw. It functions in hearing by allowing the sound vibrations from the perilymph to travel along the scala vestibule and pass through the vestibular membrane and into the endolymph of the cochlear duct where they cause movements in the basilar membrane. It then stimulates the organ of Corti, which contains the hearing receptors.

Explain how the sense of vision helps maintain equilibrium.

The eyes detect the body's position relative to its surroundings. For this reason, the eyes help the brain maintain equilibrium, especially if the other organs of equilibrium are damaged.

Describe the functions of free nerve endings, tactile corpuscles, and lamellated corpuscles.

The free nerve endings (sensory nerve fibers) are common in epithelial tissue. They are associated with the sensations of touch and pressure. Tactile corpuscles are common in hairless portions of the skin. These are sensitive to touch. Lamellated corpuscles are common in the deeper subcutaneous tissues and occur in the tendons of the muscles and the ligaments of joints. These are associated with the sensation of deep pressure.

Describe the organs of static and dynamic equilibrium and their functions.

The organs of static equilibrium are located within the vestibule, a bony chamber between the semicircular canals and cochlea. The membranous labyrinth inside the vestibule consists of two expanded chambers—an utricle and a saccule. The macula is on the anterior wall of the utricle that contains numerous hair cells and supporting cells. These sense the positions of the head and help in maintaining the stability and posture of the head and body when these parts are motionless. The organs of dynamic equilibrium are located within the three semicircular canals. Suspended in the perilymph of the bony portion of each semicircular canal is a membranous canal that ends in a swelling called the ampulla. The sensory organs are located here. These organs are called the crista ampullaris and contain a number of hair cells and supporting cells. These function to detect motion of the head and aid in balancing the head and body when they are moved suddenly.

Distinguish between the osseous and the membranous labyrinths.

The osseous labyrinth is a bony canal in the temporal bone. The membranous labyrinth is a tube that lies within the osseous labyrinth and has a similar shape.

Describe the functions of the two classes of thermoreceptors.

Thermoreceptors are actually two types of free nerve endings located in the skin. The receptors responding to heat are called heat receptors. Those, which respond to cooler temperature, are called cold receptors. Heat receptors are most sensitive to temperatures above 25o C. Cold receptors are most sensitive to temperatures between 10o C and 20o C. At intermediate temperatures, the brain interprets sensory input from different combinations of these receptors.

Explain why taste sensation is less likely to diminish with age than olfactory sensation.

This is due to the fact that the taste cells reproduce continually and only function for about three days. Damaged olfactory neurons are not replaced.

Match the ear area with the associated structure: Inner ear

cochlea

Match the ear area with the associated structure: Outer ear

eardrum

The function of the auditory tube is to

equalize air pressure on both sides of the eardrum

what are "hair cells?"

they are epithelial, but function like neurons

Salivary glands are important in taste because

they provide the fluid in which food molecules dissolve

You fill up the tub to take a hot bath, but the water is too hot to the touch. You try a second and third time within a few seconds, and it feels OK. Why?

your ability to sense heat has adapted