anatomy and physiology of sensory system ppt

All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris. 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). The exact position of the head is interpreted by the brain based on the pattern of hair-cell depolarization. The posterior cavity is the space behind the lens that extends to the posterior side of the interior eyeball, where the retina is located. Eyelid. The specific response depends on which molecule is binding to the receptor. The images in your peripheral vision are focused by the peripheral retina, and have vague, blurry edges and words that are not as clearly identified. Smell is the one sensory modality that does not synapse in the thalamus before connecting to the cerebral cortex. To use the chart, find the red tape on the floor. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize. Neurons responding to physical force, temperature, and specific chemicals to warn of (potential) damage. The extraocular muscles move the eye within the orbit. One network of neurons in the retina sends signals to one ganglion cell. Anosmia may also be related to some presentations of mild depression, because the loss of enjoyment of food may lead to a general sense of despair. Physiology concerns the functions of body partswhat they are and what they do. There are temporary causes of anosmia, as well, such as those caused by inflammatory responses related to respiratory infections or allergies. Using a tuning fork, have a subject sit with their eyes closed. Some stimuli are physical variations in the environment that affect receptor cell membrane potentials. 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. If you exhibit some degree of colorblindness, what type? Measure the distance from the image to your eye. Mechanical, chemical, or thermal stimuli beyond a set threshold will elicit painful sensations. Information is integrated along the brain stem and in the temporal cortex. It is the bipolar cell in the retina that connects a photoreceptor to a retinal ganglion cell (RGC) in the inner synaptic layer. Only a few recognized submodalities exist within the sense of taste, or gustation. Receptor cells can be further categorized on the basis of the type of stimuli they transduce. The general senses of somatosensation for the face travel through the trigeminal system. Comparisons on the chart will refer to this standard measure. Rods are so sensitive to light that a single photon can result in an action potential from a rods corresponding RGC. Receptors, Sensation, and Perception Sensory receptors Specialized cells or multicellular structures that collect information from the environment Stimulate neurons to send impulses along sensory fibers to the brain Sensation A feeling that occurs when brain becomes aware of sensory impulse Perception A person's view of the This is actually a reduced eye model, which involves some approximations. are not subject to the Creative Commons license and may not be reproduced without the prior and express written In a darkened room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. A branch may also turn into the posterior (dorsal) column of the white matter to connect with the brain. Receptor cells can be classified into types on the basis of three different criteria: cell type, position, and function. An important distinction to consider is how humans can functionally separate sensation (activation of the different receptors) as compared to perception (the conscious awareness of the sensation). Using the plates are you able to detect the image present for the presented colors? The malleus is attached to the tympanic membrane and articulates with the incus. This molecule is referred to as 11-cis-retinal. Sensory, Motor, & Integrative System - Chapter 16 Anatomy - Cram.com (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. As an Amazon Associate we earn from qualifying purchases. Receptors can be classified structurally on the basis of cell type and their position in relation to stimuli they sense. Like taste, the sense of smell, or olfaction, is also responsive to chemical stimuli. Stressed or damaged tissues release chemicals that activate receptor proteins in the nociceptors. The maculae are specialized for sensing linear acceleration, such as when gravity acts on the tilting head, or if the head starts moving in a straight line. Like sweet and bitter, it is based on the activation of G proteincoupled receptors by a specific molecule. Once the gustatory cells are activated by the taste molecules, they release neurotransmitters onto the dendrites of sensory neurons. Therefore, this RGC does not have to integrate inputs from multiple photoreceptors, which reduces the accuracy of visual transduction. Specific locations along the length of the duct encode specific frequencies, or pitches. For example, have you ever stretched your muscles before or after exercise and noticed that you can only stretch so far before your muscles spasm back to a less stretched state? Somatosensation is considered a general sense, as opposed to the special senses discussed in this section. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. The tube is normally closed but will pop open when the muscles of the pharynx contract during swallowing or yawning. mucous membrane that lines the anterior surface of the eye and the posterior surface of the eyelid. A significant amount of light is absorbed by these structures before the light reaches the photoreceptor cells. Explain your answer. Retinal is a hydrocarbon molecule related to vitamin A. (b) The olfactory receptor neurons are within the olfactory epithelium. Nociceptive Pain. This book uses the Very recent research has suggested that there may also be a sixth taste for fats, or lipids. It transmits information between these neurons and their peripheral effectors in both directions (sensory receptors, skeletal muscles and viscera). The frequency of the fluid waves match the frequencies of the sound waves (Figure 14.6). This chapter gives a basic overview of how cells are organized into tissues and how to identify tissues based on the shape, layers, and numbers of cells. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . PDF The Senses - austincc.edu Olfactory neurons will undergo adaptation and decrease signals to the brain with constant exposure to a stimulus. The cochlea is attached to the stapes through the oval window. Practicing careful dissecting is an important skill. The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors. Note the accuracy at each position of their pointing, and determine the most and least accurate positions for localization. The extraocular muscles are innervated by three cranial nerves. The main sensory modalities can be described on the basis of how each is transduced. Light passes through the eyeball via the cornea, pupil, and lens. The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. In many sensory organs, additional cells and tissues will contribute to the process of signal transduction. What may be happening with your cone cells within your retinas? The cells in the retina that respond to light stimuli are an example of a specialized receptor, a photoreceptor. It is filled with a watery fluid called the aqueous humor. Anatomy and physiology of pain. then you must include on every physical page the following attribution: If you are redistributing all or part of this book in a digital format, These modalities include pressure, vibration, light touch, tickle, itch, temperature, pain, proprioception, and kinesthesia. Head position is sensed by the utricle and saccule, whereas head movement is sensed by the semicircular canals. Comparing the peak sensitivity and absorbance spectra of the four photopigments suggests that they are most sensitive to particular wavelengths. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light. Photoreceptors in the eyes, such as rod cells, are examples of (c) specialized receptor cells. Note the shoulder positions of the subject. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows (Figure 14.10). Anatomy and physiology of the senses - PubMed Serial solutions can be applied with cotton swabs to the subject's tongue to test for sensitivity. These neurons are part of the facial and glossopharyngeal cranial nerves, as well as a component within the vagus nerve dedicated to the gag reflex. 1999-2023, Rice University. 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. Bulbous corpuscles are also present in joint capsules, where they measure stretch in the components of the skeletal system within the joint. Sensory Systems: Anatomy, Physiology and Pathophysiology provides a comprehensive description of how human sensory systems function, with comparisons of the five senses and detailed descriptions of the functions of each of them. The taste buds contain specialized gustatory receptor cells that respond to chemical stimuli dissolved in the saliva. The essential component is neurons, the major functional cells in nervous tissue. Nociception is the sensation of potentially damaging stimuli. However, cones cannot react to low-intensity light, and rods do not sense the color of light. For example, a molecule in food can serve as a ligand for taste receptors. The facial nerve connects to taste buds in the anterior third of the tongue. The difference in visual acuity between the fovea and peripheral retina is easily evidenced by looking directly at a word in the middle of this paragraph. View the University of Michigan WebScope to explore the tissue sample in greater detail. People fall into two groups known as tasters and non-tasters based on the density of papillae on their tongue, which also indicates the number of taste buds. From there, the axons split to travel to several brain regions. When you can no longer read a line accurately with one eye, then this is the acuity for that eye. A similar mechanoreceptora hair cell with stereociliasenses head position, head movement, and whether our bodies are in motion. The anterior cavity is the space between the cornea and lens, including the iris and ciliary body. The posterior cavity is filled with a more viscous fluid called the vitreous humor. Physiology of Sensory system. Sensory neurons can have either (a) free nerve endings or (b) encapsulated endings. A sound wave causes the tympanic membrane to vibrate. They preferentially absorb light at different wavelengths, shown in the figure below. Professional fighters often experience anosmia because of repeated trauma to face and head. There is more variability among individuals than accounted for by the original 1942 map (not shown, intentionally).
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