Sensory

Sense of taste

Also called gustation, involves receptors in the tongue and two different nerves that carry taste impulses to the brain.

Sense of smell

Also called olfaction, the importance of this sense is often underestimated.

Taste buds

Also known as gustatory sensory organs, are located mainly on the superior surface of the tongue.

The interpretation of smell is closely related to the sense of taste, but a greater variety of dissolved chemicals can be detected by smell than by taste.

Even though smell and taste are closely related, which sense can pick up more combinations? Smell or taste?

Temperature receptors

Give an example of free nerve endings.

Liver and gallbladder disease often cause referred pain in the skin over the right shoulder. Spasm of the coronary arteries may cause pain in the left shoulder or arm. Appendicitis can be felt as pain of the skin covering the right abdominal quadrant.

Give examples of referred pain and where it is located on the body.

Helps detect gases and other harmful substances in the environment and helps warn of spoiled food.

How can our sense of smell protect us?

These neurons extend dendrites into the nasal cavity that interact with smell chemicals, also called odorants.

How do the olfactory receptor cells interact with odorants?

Smells can trigger memories and psychological responses and are also important in sexual behavior.

How does our sense of smell affect our social lives?

We have hundreds of different odor receptors. Different odors can also activate specific combinations of receptors so that we can detect over 10,000 different smells.

How many different odor receptors do we have?

Two pathways: one is for acute, sharp pain. The other is for slow, chronic pain.

How many pathways transmit pain to the CNS?

Umami

Is a pungent or savory taste based on a response to the amino acids glutamate and aspartate, which add to the meaty taste of protein.

Referred pain

Pain that originates in an internal organ, but feels like it's coming from a more superficial part of the body, particularly the skin.

Free nerve endings

Receptors that are not enclosed in capsules but are simply branchings of nerve fibers.

Sour receptors

Receptors that detect hydrogen ions.

Sweet receptors

Receptors that respond to simple sugars.

Salty receptors

Receptors that respond to sodium.

Bitter receptors

Receptors that respond to various organic compounds

Olfactory bulb

The enlarged ending of the olfactory nerve (cranial nerve I.)

Chemical stimuli

The sense organs of taste and smell respond to what kind of stimuli?

Tactile Corpuscles

The touch receptors, they are found mostly in the dermis of the skin and around hair follicles.

Olfactory receptor cells

These are neurons embedded in the epithelium of the nasal cavity's superior region.

Papillae

These raised projections enclose the taste buds and give the tongue's surface a rough texture and help manipulate food when chewing.

Proprioceptors

These rather widespread receptors inform the brain of the amount of muscle contraction and tendon tension.

Tickle receptors

These receptors are free nerve endings associated with the tactile mechanoreceptors.

Itch

These receptors are free nerve endings that may be specific for that sensation or may share pathways with other receptors, such as those for pain.

True. Even when anesthetized, the skin can respond to pressure stimuli.

True or False: Even when anesthetized, the skin can still respond to pressure stimuli.

True. A single, strong stimulus can produce an immediate sharp pain, followed in a second or so by a slow, diffuse pain that increases in severity with time.

True or False: It is possible to feel both an acute pain and a chronic pain.

True. Itching can be a mild, short-lived annoyance or it can be chronic and debilitating.

True or False: Itching can be chronic or acute.

True. No one knows why scratching relieves an itch.

True or False: No one knows why scratching relieves an itch.

True. The olfactory receptors deteriorate with age, and food becomes less appealing. It is important when presenting food to the elderly to make the food look inviting so as to stimulate their appetites.

True or False: Olfactory receptors deteriorate with age.

True. The smell of foods is just as important in stimulating appetite and the flow of digestive juices as is the sense of taste.

True or False: The smell of foods is just as important to appetite as the sense of taste.

True. No one knows the value of tickling, but it may be a form of social interaction.

True or false: No one knows the value of tickling.

General sense

Unlike the special sensory receptors, which are localized within specific sense organs and limited to small areas, these sensory receptors are scattered throughout the body. They include touch, pressure, temperature, position, and pain.

Skin disorders, allergies, kidney disease, infection, and a host of chemicals.

What are the causes of itching?

The back of the hand and back of the neck have fewer receptors and are less sensitive to touch.

What areas of the body have fewer touch receptors, making them less sensitive to touch?

The tips of the fingers and toes contain especially numerous and close touch receptors. The lips and tip of the tongue also contain many of these receptors and are very sensitive to touch.

What body parts contain many touch receptors that are located close together?

Touch sensitivity varies with the number of touch receptors in different areas.

What determines touch sensitivity in a specific area of the body?

Proprioceptors are needed for muscle coordination, and are important in such activities as walking, running, and more complicated skills such as playing a musical instrument.

What do proprioceptors do for us?

Proprioceptors play an important part in maintaining muscle tone and good posture, and also help assess the weight of an object to be lifted so that the right amount of muscle force is used.

What do proprioceptors do regarding muscle tone and posture?

Some consider spiciness to be a sixth taste, but the chemicals involved (such as capsaicin) activate pain/touch receptors, namely the trigeminal nerve, rather than specialized gustatory cells.

What do some consider to be the sixth taste?

The olfactory nerve carries smell directly to the olfactory center in the brain's temporal cortex as well as to the limbic system.

What does the olfactory nerve do, and what part of the brain does it interact with?

Pain

What is the most important protective sense?

Taste buds are only stimulated if the substance to be tasted is in solution or dissolves in the fluids of the mouth.

What is the only way taste buds will be stimulated?

The chemicals detected must be dissolved in the mucus that lines the nose. Because receptors are located high in the nasal cavity, you must "sniff" to bring odors upward in your nose.

What is the only way we are able to 'smell' smells?

The hypothalamus helps adjust temperature according to the temp. of the circulating blood.

What part of the brain controls body temperature?

The cerebellum is the main coordinating center for the impulses that come from proprioceptors.

What part of the brain coordinates impulses from the proprioceptors?

Receptors for pain are widely distributed free nerve endings. They are found on the skin, muscles, and joints and to a lesser extent in most internal organs (including the blood vessels and viscera.) Basically, pain receptors are everywhere.

Where are pain receptors located on the body?

The sensory receptors for deep pressure are located in the subcutaneous tissues beneath the skin and also near joints, muscles, and other deep tissues. They are sometimes referred to as receptors for deep touch.

Where are receptors for deep pressure located?

Temperature receptors are widely distributed in the skin, and there are separate receptors for heat and cold.

Where are temperature receptors located on the body?

The nerves of taste include the facial and the glossopharyngeal cranial nerves (VII and IX.)

Which nerves are involved in taste?

The interpretation of taste is probably accomplished by the brain's lower frontal cortex, although there may be no sharply separate gustatory center.

Which part of the brain is most likely responsible for producing taste?

Receptors located in muscles, tendons, and joints aid in judging body position and relative changes in the locations of body parts.

Which receptors help us judge body position and relative changes in the locations of body parts?

Epithelial cells (gustatory cells)

Within each taste bud, these cells respond to one of five basic tastes.

Glutamate

is found in MSG (monosodium glutamate), a flavor enhancer used in some processed foods and some restaurants.

Kinesthesia

is sometimes used to describe dynamic, or movement-associated, aspects of proprioception.