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By the end of this section, you will be able to:
  • Describe different types of sensory receptors
  • Describe the structures responsible for the special senses of taste, smell, hearing, balance, and vision
  • Distinguish how different tastes are transduced
  • Describe the means of mechanoreception for hearing and balance
  • List the supporting structures around the eye and describe the structure of the eyeball
  • Describe the processes of phototransduction

A major role of sensory receptors is to help us learn about the environment around us, or about the state of our internal environment. Stimuli from varying sources, and of different types, are received and changed into the electrochemical signals of the nervous system. This occurs when a stimulus changes the cell membrane potential of a sensory neuron. The stimulus causes the sensory cell to produce an action potential that is relayed into the central nervous system (CNS), where it is integrated with other sensory information—or sometimes higher cognitive functions—to become a conscious perception of that stimulus. The central integration may then lead to a motor response.

Describing sensory function with the term sensation or perception is a deliberate distinction. Sensation is the activation of sensory receptor cells at the level of the stimulus. Perception is the central processing of sensory stimuli into a meaningful pattern. Perception is dependent on sensation, but not all sensations are perceived. Receptors are the cells or structures that detect sensations. A receptor cell is changed directly by a stimulus. A transmembrane protein receptor is a protein in the cell membrane that mediates a physiological change in a neuron, most often through the opening of ion channels or changes in the cell signaling processes. Transmembrane receptors are activated by chemicals called ligands. For example, a molecule in food can serve as a ligand for taste receptors. Other transmembrane proteins, which are not accurately called receptors, are sensitive to mechanical or thermal changes. Physical changes in these proteins increase ion flow across the membrane, and can generate an action potential or a graded potential in the sensory neurons.

Sensory receptors

Stimuli in the environment activate specialized receptor cells in the peripheral nervous system. Different types of stimuli are sensed by different types of receptor cells. Receptor cells can be classified into types on the basis of three different criteria: cell type, position, and function. Receptors can be classified structurally on the basis of cell type and their position in relation to stimuli they sense. They can also be classified functionally on the basis of the transduction    of stimuli, or how the mechanical stimulus, light, or chemical changed the cell membrane potential.

Structural receptor types

The cells that interpret information about the environment can be either (1) a neuron that has a free nerve ending    , with dendrites embedded in tissue that would receive a sensation; (2) a neuron that has an encapsulated ending    in which the sensory nerve endings are encapsulated in connective tissue that enhances their sensitivity; or (3) a specialized receptor cell    , which has distinct structural components that interpret a specific type of stimulus ( [link] ). The pain and temperature receptors in the dermis of the skin are examples of neurons that have free nerve endings. Also located in the dermis of the skin are lamellated corpuscles, neurons with encapsulated nerve endings that respond to pressure and touch. The cells in the retina that respond to light stimuli are an example of a specialized receptor, a photoreceptor    .

Questions & Answers

Card 5 / 12: For whom would an appreciation of the structural characteristics of the human heart come more easily: an alien who lands on Earth, abducts a human, and dissects his heart, or an anatomy and physiology student performing a dissection of the heart on her very first day of class? Why?
Gelowe Reply
what are regular shaped cells with granules in the cytoplasam
Kabita Reply
I need sylubuss of clinical officers book
Omary Reply
cholesterol normal value is
less than 200mg/dl
100 to159mg/dL
Early this wk. I had some "A & P" questions & answers unfortunately didn't save them, Is there any way I can have them back ,so as 2 save them?. Thnx.
what are the functions of the female reproductive system
Lister Reply
it produces the female egg necessary for reproduction, called the Ova or Oocytes. The system is designed to transport the Ova to the site of fertilization.
Female reproductive system was mainly functioned to produce ova(ovum) (female eggs) Into which will be fertilized by male gamete to produce zygote
absolutely right
wa qalad nimco rage iska hubi
waxwalba ka fikirbay ubaahantahay
ha wayo jawabtoda wa qabyo nimco wey ku raacdat
ha wayo jawabtoda wa qabyo nimco wey ku raacday
wxayaabaha qaarkood waaa in aan u feejignaano
asc if I try female reproductive system has two function the first is to produce egg cell and the second is to protact and nourish the offspring until birth
what is stercobilinogen
Hancerich Reply
fecal urobilinogen. Created by bacteria in the gut. a chemical that gives feces brown color.
next question pls.
The rate of diffusion increases if the
What's the answer?
it's a breaking down of haemoglobin and it's a chemical made by bacteria
Thnx Dev Raj.
yup so any more
yes I sure do need more "Questions" & "Answers". I'm learning whole lot. Thnx.
what is the greatest muscle of the body
Lungu Reply
gluteus maximus
pls!!! more "A&P" questions & answers. Thnx.
Gluteus maximus
Describe anatomy of cardiovascular system?
cardiovascular system is a group of organs coming together to perform the circulation of blood. The organs invoked are the heart and the blood vessels with blood being the tissue. The heart is a pump and it pumps oxygenated blood through the systemic circuit and deoxygenated blood through the pulmon
pulmonary circuit.
more A&P questions pls. Thnx.
If an ANOVA yields a significant F value, you could rely on ________ to test significant differences between group means.
Dane Reply
what's ANOVA
analysis of variance
plz what you mean with "ANOVA" first
anova means analysis of variance, a statistical method in which the variation in a set of observations is divided into distinct components.
M value ot test
What does it mean by M value ot test?
formation of red blood cells
Biketi Reply
explain why... lower back pain in ovarian cancer
Srijoni Reply
we says that protoplasm is the living part of us How?
Muzamil Reply
is the leaving part of our cellular structure.
it is the leaving part of our blood cellular structure also
what is receptor?
Preity Reply
an organ or cell able to respond to light, heat, or other external stimulus and transmit a signal to a sensory nerve.
Has anyone taken the first exam?
hey what is the process after your food is swallowed? how long does it take to get to the stomache until it is released as waste?
Fednise Reply
that is such a broad question. as you begin to swallow its various doses down the alimentary canal that brings the food into your stomach.then depending on whether it's a protein carbohydrate fat that dictates what function takes place in your stomach. these are all steps of digestion.
typo sorry it's peristalsis , wave-like projections that push food down your alimentary canal etc. digestion starts in your mouth ends in your large intestines (colon anus)
some of the many processes of digestion include hydrolysis dehydration synthesis denaturation of proteins etc. you have to be more specific.
there's many different contributing factors the how long it takes food to convert into waste. remember fats, triglycerides proteins and carbohydrates all breakdown two different monomers and structures. you should be looking up metabolic processes.
depending how much fiber you have in your diet dictates how much water is brought to your intestines that has to do with excretion whether fiber is insoluble or soluble. this is an anatomy and physiology app. to simply say the stomach will empty its contents in 2 to 3 hours would do you a disservice
can the study of anatomy relate to medical technologies
Lean Reply
how can I understand micro biology and anatomy better.
someone to help me understand glycogeneogenesis
what are the major branches of the aorta?
look youtube video

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