Do you and your lab partner vary in your sensitivities? The transparent cornea covers the anterior tip of the eye and allows light to enter the eye. Cone outer segments are short, tapered shapes with folds of membrane in place of the discs in the rods. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. Chapter 10: Sensory Physiology Author: Kindy Last modified by: Kindy Created Date: 10/3/1999 7:36:15 PM . They alter the lens to aid focusing. Below, list the micromolar concentrations of mint and circle the one where you can begin to smell the mint. This creates a blind spot in the retina, and a corresponding blind spot in our visual field. OpenStax is part of Rice University, which is a 501(c)(3) nonprofit. Some stimuli are ions and macromolecules that affect transmembrane receptor proteins when these chemicals diffuse across the cell membrane. spearmint, orange, anise). The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by suspensory ligaments, or zonule fibers. Eyelid. Repeat while standing with your right or left side closest to the board, and note front-to-back swaying, First with eyes open and then with eyes closed. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. The fluid-filled tube, now called the scala tympani, returns to the base of the cochlea, this time travelling under the cochlear duct. If you have missed laboratory or class; complete the makeup work below. The taste known as umami is often referred to as the savory taste. The neural signals generated in the vestibular ganglion are transmitted through the vestibulocochlear nerve to the brain stem and cerebellum. The middle ear is connected to the pharynx through the Eustachian tube, which helps equilibrate air pressure across the tympanic membrane. Olfactory neurons will undergo adaptation and decrease signals to the brain with constant exposure to a stimulus. It transmits information between these neurons and their peripheral effectors in both directions (sensory receptors, skeletal muscles and viscera). The other tastes result from food molecules binding to a G proteincoupled receptor. Comparing the peak sensitivity and absorbance spectra of the four photopigments suggests that they are most sensitive to particular wavelengths. However, cones cannot react to low-intensity light, and rods do not sense the color of light. Once any sensory cell transduces a stimulus into a nerve impulse, that impulse has to travel along axons to reach the CNS. Each of the senses is referred to as a sensory modality. An individual sensory modality represents the sensation of a specific type of stimulus. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. Use a microscope to explore the cellular aspect of a taste bud. Some sources will also refer to this structure as the pinna, though that term is more appropriate for a structure that can be moved, such as the external ear of a cat. The standing sound wave generated in the cochlea by the movement of the oval window deflects the basilar membrane on the basis of the frequency of sound. 3 285-296 doi: 10.1083/jcb.201003144). The surface of the tongue, along with the rest of the oral cavity, is lined by a stratified squamous epithelium. The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. The incus, in turn, articulates with the stapes. consent of Rice University. Dr. Reed discovered that she is a non-taster, which explains why she perceived bitterness differently than other people she knew. There are four types of papillae, based on their appearance (Figure 14.3): circumvallate, foliate, filiform, and fungiform. (Micrograph provided by the Regents of University of Michigan Medical School 2012), (a) The olfactory system begins in the peripheral structures of the nasal cavity. Nociceptive Pain. Deep pressure and vibration is transduced by lamellated (Pacinian) corpuscles, which are receptors with encapsulated endings found deep in the dermis, or subcutaneous tissue. Blunt force trauma to the face, such as that common in many car accidents, can lead to the loss of the olfactory nerve, and subsequently, loss of the sense of smell. The stereocilia extend up from the hair cells to the overlying tectorial membrane, which is attached medially to the organ of Corti. Two types of somatosensory signals that are transduced by free nerve endings are pain and temperature. Another physical stimulus that has its own type of receptor is temperature, which is sensed through a thermoreceptor that is either sensitive to temperatures above (heat) or below (cold) normal body temperature. The molecule that activates this receptor is the amino acid L-glutamate. She recognized that her sense of taste was unique compared with other people she knew. Temperature receptors are stimulated when local temperatures differ from body temperature. vision, taste). Receptor cell types can be classified on the basis of their structure. The Eustachian (or auditory) tube connects the middle ear cavity to the pharynx (it is an evolutionary descendant of pharyngeal pouches). Therefore, the olfactory neurons are regularly replaced within the nasal epithelium, after which the axons of the new neurons must find their appropriate connections in the olfactory bulb. The types of nerve endings, their locations, and the stimuli they transduce are presented in Table 14.1. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. Stressed or damaged tissues release chemicals that activate receptor proteins in the nociceptors. Find an individual taste bud and draw it in the space provided. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. Umami is a Japanese word that means delicious taste, and is often translated to mean savory. Some bitter molecules depolarize gustatory cells, whereas others hyperpolarize gustatory cells. Retinal is a hydrocarbon molecule related to vitamin A. In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. Receptors are the cells or structures that detect sensations. The human sensory system is highly evolved and processes thousands of incoming messages simultaneously. In addition, each photoreceptor cell of the fovea is connected to a single RGC. Using the model of the ear find the following structures: ear canal, tympanum (tympanic membrane), ossicles (malleus, incus, stapes in order moving inward into the ear), cochlea, semicircular canals. This book uses the BIO 1414 Human Anatomy & Physiology II - BIO 1414 Human Anatomy & Physiology II Unit 3 Autonomic Nervous System and Senses Part 1 By: Robert F. Allen, Professor of Biology Conjunctiva Covers the inner . Of course, it is often sweetened so that the sour taste is masked. Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. 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. The first half of the pathway is the projection from the RGCs through the optic nerve to the lateral geniculate nucleus in the thalamus on either side. In addition to describing anatomy and function, the book also provides insight as to how sensory information is processed in the brain to provide the basis for . The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. At the molecular level, visual stimuli cause changes in the photopigment molecule that lead to changes in membrane potential of the photoreceptor cell. At the uppermost tip of the cochlea, the scala vestibuli curves over the top of the cochlear duct. Proprioceptive Sensations- relating to the physical state of the body (position, tendons, muscles, equilibrium) Visceral Sensations- sensations from the internal organs Deep Sensations- come from the deep tissues (fascia, muscles, and bone) 4 Detection and Transmission of Tactile Sensations Interrelaitons Among the Tactile Sensations of Touch, Cell Biology, 2010 vol. However, these are not all of the senses. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Proprioceptors - near junction General Sense Organs between tendons and muscles. The major sensory organs can be grouped based on various characteristics, i.e. are licensed under a, Structural Organization of the Human Body, Elements and Atoms: The Building Blocks of Matter, Inorganic Compounds Essential to Human Functioning, Organic Compounds Essential to Human Functioning, Nervous Tissue Mediates Perception and Response, Diseases, Disorders, and Injuries of the Integumentary System, Exercise, Nutrition, Hormones, and Bone Tissue, Calcium Homeostasis: Interactions of the Skeletal System and Other Organ Systems, Embryonic Development of the Axial Skeleton, Development and Regeneration of Muscle Tissue, Interactions of Skeletal Muscles, Their Fascicle Arrangement, and Their Lever Systems, Axial Muscles of the Head, Neck, and Back, Axial Muscles of the Abdominal Wall, and Thorax, Muscles of the Pectoral Girdle and Upper Limbs, Appendicular Muscles of the Pelvic Girdle and Lower Limbs, Basic Structure and Function of the Nervous System, Circulation and the Central Nervous System, Divisions of the Autonomic Nervous System, Organs with Secondary Endocrine Functions, Development and Aging of the Endocrine System, The Cardiovascular System: Blood Vessels and Circulation, Blood Flow, Blood Pressure, and Resistance, Homeostatic Regulation of the Vascular System, Development of Blood Vessels and Fetal Circulation, Anatomy of the Lymphatic and Immune Systems, Barrier Defenses and the Innate Immune Response, The Adaptive Immune Response: T lymphocytes and Their Functional Types, The Adaptive Immune Response: B-lymphocytes and Antibodies, Diseases Associated with Depressed or Overactive Immune Responses, Energy, Maintenance, and Environmental Exchange, Organs and Structures of the Respiratory System, Embryonic Development of the Respiratory System, Digestive System Processes and Regulation, Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder, Chemical Digestion and Absorption: A Closer Look, Regulation of Fluid Volume and Composition, Fluid, Electrolyte, and Acid-Base Balance, Human Development and the Continuity of Life, Anatomy and Physiology of the Testicular Reproductive System, Anatomy and Physiology of the Ovarian Reproductive System, Development of the Male and Female Reproductive Systems, Changes During Pregnancy, Labor, and Birth, Adjustments of the Infant at Birth and Postnatal Stages. You will have to identify these structures using both the sheep or cow eye and the models. Golgi tendon organs similarly transduce the stretch levels of tendons. Toward the edges of the retina, several photoreceptors converge on RGCs (through the bipolar cells) up to a ratio of 50 to 1. On top of the otolithic membrane is a layer of calcium carbonate crystals, called otoliths. Taste can be identified using solutions of chemicals known to stimulate distinct receptor proteins. These cells release neurotransmitters onto a bipolar cell, which then synapses with the optic nerve neurons. Are you very sensitive to tastes? Within the realm of physiology, senses can be classified as either general or specific. Modality refers to the way that information is encoded, which is similar to the idea of transduction. Some of the branches will synapse with local neurons in the dorsal root ganglion, posterior (dorsal) horn, or even the anterior (ventral) horn, at the level of the spinal cord where they enter. (Micrograph provided by the Regents of University of Michigan Medical School 2012). A similar mechanoreceptora hair cell with stereociliasenses head position, head movement, and whether our bodies are in motion. The first two tastes (salty and sour) are triggered by the cations Na+ and H+. When each of these muscles contract, the eye moves toward the contracting muscle. Learning Objectives. Non-tasters can taste food, but they are not as sensitive to certain tastes, such as bitterness. Sensory systems include organs, tissues, and cells that receive stimuli from the environment and send this information to the brain for processing. You can estimate this distance (d, in mm) of your retinal structures by recording the distance when the image disappears (x), and measuring the distance between the cross and circle in the image (d). Also, what is referred to simply as touch can be further subdivided into pressure, vibration, stretch, and hair-follicle position, on the basis of the type of mechanoreceptors that perceive these touch sensations. Receptor cells can be classified into types on the basis of three different criteria: cell type, position, and function. Other stimuli include the electromagnetic radiation from visible light. The membrane covering the round window will bulge out or pucker in with the movement of the fluid within the scala tympani. The macula is composed of hair cells surrounded by support cells. If you differ, then provide a possible explanation as to why: This lab has been adapted from Rice University and is licensed under a Creative Commons Attribution License License (3.0). As the fluid waves move through the scala vestibuli and scala tympani, the basilar membrane moves at a specific spot, depending on the frequency of the waves. The focused image is directed toward the fovea (or fovea centralis), which contains the highest density of photoreceptor neurons. Physiology of Sensory system. Mechanoreceptors in the skin, muscles, or the walls of blood vessels are examples of this type. Terms in this set (50) Five basic senses. Sensation is the activation of sensory receptor cells at the level of the stimulus. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve. As stated above, a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Different types of stimuli are sensed by different types of receptor cells. Specific wavelengths of sound cause specific regions of the basilar membrane to vibrate, much like the keys of a piano produce sound at different frequencies. The tongue is covered with small bumps, called papillae, which contain taste buds that are sensitive to chemicals in ingested food or drink. General senses often contribute to the sense of touch, as described above, or to proprioception (body movement) and kinesthesia (body movement), or to a visceral sense, which is most important to autonomic functions. There are at least 30 different genes coding for bitter taste receptors. The cochlea is attached to the stapes through the oval window. Eventually, patterns of ganglion cells signals are integrated within the brain (in the occipital cortex) to generate the perception of complex images. In skeletal muscle tissue, these stretch receptors are called muscle spindles. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 14.18). Stretch receptors monitor the stretching of tendons, muscles, and the components of joints. One network of neurons in the retina sends signals to one ganglion cell. Watch this video to learn more about how the structures of the ear convert sound waves into a neural signal by moving the hairs, or stereocilia, of the cochlear duct. Anatomy and physiology of pain. The organs of Corti contain hair cells, which are named for the hair-like stereocilia extending from the cells apical surfaces (Figure 14.8). In this lab, we will explore the anatomy & physiology used for interpreting the environment both within and outside our bodies. Similar to the smell test, list the concentrations of the two substances and circle the one where you can begin to taste the substance. sucrose), Bitter (various, common test is Ca2+), sour (H+), and umami (glutamate). Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. There, amacrine cells additionally contribute to retinal processing before an action potential is produced by the RGC. The center of the retina has a small indentation known as the fovea. The affinity for each of these molecules varies, and some will taste sweeter than glucose because they bind to the G proteincoupled receptor differently. This process is called photoisomerization. Stimuli are of three general types. You will work in groups of two or three to dissect an eye.
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