b. In human, extreme concentration of touch receptors are in the fingertips and lips. In the front, the sclera continues as a clear, trans­parent membrane, the cornea. The taste bud is innervated by glos­sopharyngeal nerve. Welcome to NotesOnZoology.com! 14.17). The earliest reference we have to unusual animal behavior prior to a significant earthquake is from Greece in 373 BC. These cells and their nerve fibres constitute the organ of corti, the hearing organ proper. The retinal layer is highly innervated by the optic nerve. In the metazoan, portions of the skin are specialised to form eyes. The utricle and saccule are concerned with the position of the head. and located on the stretchable area of the cuticle. This allows them to feel the movement of other animals in the water nearby. This helps them to locate the presence of warm-blooded prey. A very small number of nematodes have structures which may play a … There are five sense organs – eyes, ears, nose, tongue, and skin. Still the basic features and functions of different compo­nents are similar in all groups of vertebrates. Action of wings in flight is controlled by proprioreceptor cells present at the base of the halteres. The type known as tymponal organ, the most complex and efficient organ of sound perception is found in moths. Rheoreceptors or detectors of low vibra­tions in water, are present in fishes and aquatic amphibians. 14.10, 14.11) consists of three semicircular canals (except agnatha) and two small, hollow sacs, the utricle and saccule. Cutaneous Sense Organs. The ear in mammals though basically simi­lar to that of other tetrapod’s, is more ela­borate. A research team has developed a new theory that can predict the movement of an animal's sensory organs -- such as eyes, ears and nose -- while searching for something vital to its life. ISBN 9780123957696, 9780323163323 A horse’s hearing is much keener than ours. 14.11). All animals are sensitive to variations in temperature. Further, in mam­mals, incus and malleus in the middle ear developed from the quadrate and articular, respectively. In addition to the membranous labyrinths, eyes and proprioreceptors help in maintain­ing equilibrium. 69.73.177.34. Investigation Of Animal Behaviour. Due to the tendency of the eye-ball to remain globu­lar normally, there is a pull on the lens which keeps it flat. The divergent rays from the near object are thus focussed to form a clear image on the retina. Information may be sent intentionally, as in a courtship display, or unintentionally, as in the transfer of scent from predator to prey. They differ in structures in different arthropods. The sense organs of the vertebrate skin include a variety of kinds, among which are organs of touch and pressure, temperature, pain, and in some aquatic forms, taste, and lateral-line organs that are stimulated by currents of water. The retina is composed of a layer of pig­mented epithelium constituted by receptor cells, the rods and cones (Fig. Present day verte­brates possess a pair of image forming, simple, lateral eyes. Sense organs that respond to touch and to chemical stimuli play an important role in the behaviour of nematodes, as most of these animals live in the dark in soil, in mud, or in the organs and tissues of other organisms. It is a hollow ball­-like structure with a lens in front and a sensitive screen behind and largely corre­sponds to an ordinary photographic camera (Fig. The sense of touch is detected by a variety of different types of mechanorecetpors that are embedded in the skin, mucous membranes, muscles, joints, internal organs, and cardiovascular system. The eyes of cephalopods are camera type like those of the vertebrates. It consists of sclera and cornea. The layer beneath the sclera is called tunica vasculosa. The taste cells are stimulated by substances in solution. The vertebrate eyes are camera-type eyes. The internal ears or membra­nous labyrinths control these functions. c. Touch corpuscles (Fig. The pulmonate molluscs move towards the food, even after removal of both the eyes by surgery. But the precise position and orientation these sense organs take over time during behavior is not intuitive, and current theories do not predict these positions and orientations well. The ability to differentiate the orientation of the body in relation to its surroundings and to maintain an equilibrium is present in all vertebrates. Cooper, P.C. Normally, the eye is focused for distant vision. The lens is enclosed in a trans­parent capsule and suspended from the ciliary body by suspensory ligament. The iris is composed of two layers of muscle fibres, one circular and the other radiating and contain pigment cells. Some buds are specific while others may be stimulated by more than one tastes. The inner posterior five-sixths of the sclera is lined by choroid. These processes can be studied at various levels of organization from membranes through to organelles, cells, organs, organ systems, and to the whole animal. Muller’s Law of specific nerve energies: Sensation perceived depends on the part of nervous system activated, and not on the sense organ stimulated. Horses can hear low to very high frequency sound, in the range of 14 Hz to 25 kHz (human range = 20 Hz to 20 kHz). Although we will discuss them in other pages related to other animal organs, we give here a more detailed description. 14.12). These systems are normally known as senses. The whole space between the lens and the retina, about four-fifths of the eye-ball, is occupied by a thin jelly, the vitreous humor, enclosed in a delicate, transparent membrane, the hyaloid membrane. It consists of parallel slits of varying length in the cuticle, resembling the strings of a lyre. The olfactory receptors are located in the posterior part of the nasal cavities. 14.9A) consist of ovoidal groups of sensory cells innervated by a special nerve. Situated close to the blind spot is the macula lutea (yellow spot). Lateral Line Sense Organs And Their Importance In Fish Behavior Lateral Line Sense Organs And Their Importance In Fish Behavior by Nikolaĭ Nikolaevich Disler, Lateral Line Sense Organs And Their Importance In Fish Behavior Books available in PDF, EPUB, Mobi Format. Since the vertebrates live in different media, their eyes are also adapted to see under water, in bright light, in dim light and in darkness (in relation to human vision). It is presumed that with their specific electric organs the fishes create a pulsating electric field around them and any object in the surroundings with a different electrical conductivity than that of the water will disturb the field. With the change of surroundings from water to air on land, the organs of hearing underwent profound changes. Olfactory receptors in moths and ants are quite power­ful. In the invertebrates they are concerned with transmitting postural information and are present in crustacea, and insects. The fishes, electric ray or elec­tric eel can generate electric pulses exceeding 500 volts. The anterior and posterior canals are vertical in position while the external one is in horizon­tal plane. Change of head position (static equili­brium) affects the gravitational pull on the otoliths and hence the pressure on the sen­sory hair cells in the utricle and saccule in relation to gravity. 14.18), against the choroid and several layers of sensory and connector neurons and their axons on the inner side. Complex behaviour, thus, is the product of an integrated series of changes in cell chem­istry; initiated by receptor cells and carried on by sensory interneurons and motor cells and muscles. The flow, of endolymph in the semicircular canals stimulates the sensory cells in the ampulla. The co­chlea, the part of the membranous labyrinth concerned with hearing is an outgrowth from the saccule. No specialised thermo receptors are on record in invertebrates. Bowl-shaped, black pigmented ocelli contain­ing clusters of photosensitive cells are present in planaria (Fig. The sound waves are concentrated and directed by the auricle through the external auditory meatus. The rods are more numerous and sensitive to dim light and colours while the cones are less numerous and respond to bright light. c. The cochlea (Gr. With their large brains, elaborate sense organs and complex behaviour, cephalopods are among the world's most highly evolved invertebrates. The base of the triangle or the basilar membrane is lined by neuroepithelial cells and nerve fibres. It is believed that substances containing volatile particles when dissolved in the fluid of the nasal cavity, releases the volatile par­ticles, which stimulate the receptor cells. The bud is in communication with the surroundings through a minute pore and many microvilli project into the pore. Just watch as horse as it reacts to sounds all around. Sweet, sour, salt and bitter are four basic tastes. The cavity is lined with either a simple squamous or a cubical epithelium. Cells sensitive to temperature variations are present in all vertebrates. statas = standing + kystis = sac) are ‘organs of balance in arthropods and molluscs. To survive, animals have to sense their environment. Fishes are highly sensitive to temperature variations and can detect variation as low as 0.1°C. In some cases, sand particles (Fig. Eye spots are present in leech. The proprioreceptors are tonic receptors, and register stress changes in the exoskeleton. One end of the cell responds to the chemical’ stimuli while the other end is continuous with a neuron. The retina acts as a sensitive screen on which the images of objects are focused. Purchase Sense Organs Integration, and Behavior - 1st Edition. Electroreceptors are sensory cells which can detect changes in the electric field of the surroundings. The point where the optic nerve enters the retina is known as blind spot. Three structures — the vestibule, the mem­branous labyrinth and cochlea lodged in a cavity, the bony labyrinth constitute internal ear. Primitive societies first domesticated animals as a convenient means of meeting immediate … The ear, acting as a funnel for capturing sound and sending it down into the ear canal, swivels and seems to reach toward the sound. Sound waves travel at about 1,088 feet (332 metres) per second. In reptiles (Fig. The membranous labyrinth is filled with a fluid, the endolymph. A pair of halteres, the modi­fied hind wings in flies and mosquitoes take care of maintaining stability by controlling lift, rotation and landing in their flight. An animal that survives by getting a head start on predators necessarily develops a keen sense of hearing. Maintenance of body equilibrium is es­sential for the normal activities in an animal. The pigment allows light to reach the receptors only from above and slightly to the front, but image formation does not occur. Animal Physiology. 14.16), the nerve degenerates in the embryo and the eye lost its function. These are also known as lateral line sense organs. Some animals can sense electric and magnetic fields. Disclaimer Copyright, Zoology Notes | Exclusive Notes on Zoology for Students, Sense Organs of Uromastix (With Diagram) | Chordata | Zoology, Sense Organs of Rabbit (With Diagram) | Vertebrates | Chordata | Zoology, Sense Organs in Pigeons (With Diagram) | Vertebrates | Chordata | Zoology, Systems Found in the Animal Body | Zoology. Patches of elongated sensory cells produced into hair-like processes are present in the ampullae, utricle and saccule. This service is more advanced with JavaScript available, Physiology of Nematodes 14.9) are: a. Crocs use … This initiates impulses, which are trans­mitted to the site of smell in the brain. 14.3) are present at the centre. The tympanum shifted from surface to inside and the passage from it to the ex­terior, the external ear appeared. The sensory neurons attached to the apical bod­ies, the scolopodia are bipolar. The ears, eyes, nose, tongue and skin are the five sense organs. 32.12B). Many animals have much better senses of smell and hearing than humans do. A taste cell may be connected with only one neuron or more than one. Receptors in our muscles and joints inform our sense of body position. The high activity is due to the presence of maximal number of receptor cells, all cones, in the area. The first new acquisition in amphibia was the ear drum or tympanum on the body surface, which enclosed a space, the middle ear, external to the internal ear. A complete history of transformation of simple ear of fishes to the complex ear of mammals is available. They are capable of registering muscle tension or stretch and ensure harmonic contraction of all the muscles involved in a single move­ment. 14.7) are more specialised them those of planaria and leech. 14.10). Not logged in This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. It opens into the mouth and known as Jacobson’s organ (Fig. Eyes or organs of vision are two in num­ber in a mammal, like that of any other ver­tebrate. Animals rely on some senses … The eye lies safely in a bony orbit of the skull, excepting a small exposure in front bounded by the eyelids. Statocysts (Gr. The olfactory receptors can detect objects from a distance while the gustatory receptors are active only in contact with the substance. The anterior continuation of the choroid is made of non-striated muscle fibres, the ciliary muscle and known as ciliary body. It is filled with air coming from the nasopharynx through the auditory or eustachian tube lined with a ciliated epithelium. The retina lines about posterior three-fourths of the eye-ball. 14.9D) the naked axon is surrounded by a. complex, laminated sheath containing fluid. The free ends of the taste cells bear microvilli. Withers, in Encyclopedia of Ecology, 2008. The organs detect low vibrations in water and enable the fish to move correctly in turbid water and also in darkness. In fact, what is commonly referred to as “touch” involves more than one kind … Receptors for smell and taste are chemo- receptors. They use their senses to look for food and so protection. The mammalion ear consists of three dis­tinct parts — external ear, middle ear or tym­panic cavity and internal ear (Fig. These sense organs are capable to differentiate between chemicals and thereby help in controlling the activities of animals in relation to its surroundings, in the selection of food, in social behaviour, in defence from predators, in selection of mate and others. All sense organs respond to stimuli by producing nerve impulses that travel to the brain via a sensory nerve. It is a round capsule with a lens formed of elon­gated cells at the anterior wall and the pos­terior wall resembles a retina, made of an inner layer of rod-like visual elements and an outer layer of nerve fibres (Fig. The eye is moved by six muscles— superior oblique, inferior oblique, superior rectus, inferior rectus, anterior rectus and posterior rectus. Sense organs capable to respond to light stimulus are photoreceptors. These are internal receptor organs present in skeletal muscles, tendons and joints. The neuroepithelial cells of the organ of corti are stimulated by the motion and the nerve impulses are send to the hear­ing area of the cerebrum in the brain through the auditory nerve. 14.2. Animal behaviour is categorised into 4 distinct categories like instinct, imprinting, conditioning, and imitation. A narrow canal, the hyaloid canal, filled with lymph runs for­ward through the vitreous body from the entrance of the optic nerve to the posterior surface of the lens. A lens to concentrate light and a great increase in the number of photoreceptor cells led to the evolution of image forming eyes. End bulbs (Fig. Animal physiology is the study of how animals work, and investigates the biological processes that occur for animal life to exist. This enables the fishes to know that they are en­tering a different body of water and to regu­late their migration. The rods and cones receive the visual impulses. Feeding behavior mostly results from the interaction between organoleptic properties of food and pet sensorial equipment. Snakes use a special apparatus called Jacobsen's organ to smell. b. The cnidocil being touched, the cnidocyte contracts violently dis­charging the nematocyst. Each bud contains two types of narrow cells, the taste cells and supporting cells. Two lateral line sense or­gans, each with a series of lateral line organs or neuromasts (Fig. SENSE ORGANS A structure in animals that is specialized for receiving external or internal stimuli and transmitting them in the form of nervous impulses to the brain In animals, an organ or part that is sensitive to a stimulus, as of sound, touch, or light. This suggests some sort of sense of smell are present in them. 14.15). The sensory cells are innervated by the branches of the auditory nerve. Vibrations of the mem­brane of the round window neutralize the wave motion in the endolymph. Clusters of simple eyes or ocelli in the jelly fishes help them to orient to light. These sense organs are capable to differentiate between chemicals and thereby help in controlling the activities of animals in relation to its surroundings, in the selection of food, in social behaviour, in defence from predators, in selection of mate and others. 14.1) in the cnidocytes (cnidoblasts). A small depression, the fovea centralis at the centre of this region is the site of greatest visual activity. The neuroepithelial cells are arranged side by side and a majority of them are long and narrow (Fig. It consists of two components, the skin covered, cartilagenous pinna or auricle and the slightly S-shaped auditory canal or exter­nal auditory meatus extending from auricle to tympanum. A statocyst is usually an oval sac, may or may not be in communication with the exterior and lined internally by a sensory membrane bearing processes or hairs. The nerve fibres join to form the olfactory nerve, which passes directly to the olfactory lobe of the brain. Many fish sense their surroundings with a lateral line system, which detects changes in water pressure. Anecdotal evidence abounds of animals, fish, birds, reptiles, and insects exhibiting strange behavior anywhere from weeks to Photoreceptors in different degrees of perfection are present in the majority of the animals. Otoliths are pushed back upon certain hair cells of the utricle and saccule during rapid forward movement (linear accelaration). The outermost layer of the eye-ball, tunica fibrosa, skeletal in function, and maintains the rigidity of the eye-ball. Unfortunately very little physiological work has been done on nematode sense organs and in most cases their function has had to be assumed from their location on the body of the nematode, or from their structure. The organ of corti is innervated by the auditory nerve. The iris incompletely divides the space into a large anterior and a very narrow posterior chamber. Each sensory cell has a -hair projecting outside through the pore. Lithocysts (Fig. Isolated light sensitive cells are scattered over the body surface in earthworm. Author: Nikolaĭ Nikolaevich Disler Publisher: ISBN: Size: 18.75 MB Format: PDF, Docs View: 5608 Get Books. The wall of the eye-ball has three concen­tric layers—outer tunica fibrosa, middle tunica vasculosa and inner retina. Non-functioning of proprioreceptors causes numbness of an organ. The expanded part adjacent to the middle ear and containing the oval and round windows constitute the vestibule. An inverted image of the object is formed on the retina and this is conveyed to the visual centres of the optic lobes in the brain by the optic nerves. Content Guidelines 2. 14.14) is made of olfactory cells, sensitive to smell. In mammals, the buds are located on the papillae in the tongue and soft palate. d. Pecinian corpuscle (Fig. Horses ears are funnel shaped and very mobile. Not much is known about sense of smell in the invertebrates. It can be adjusted for near vision by increasing the convexity of the lens. Neurochemical information coming from cerebral cortex affects hypothalamus, which stimulates endocrine system to alter the behaviour of the animal. In the entire animal kingdom, the duck-billed platypus, along with echidnas (ant-eaters), is the only mammal that can… Two types of eyes—ocelli or simple eyes and compound eyes, are found in arthropods. 2. They are known as cristae acoustica in utricle and saccule and cristae ampularis in the ampulla. Four types of mechanoreceptors are present in invertebrates: The tactile (touch) receptor is a phasic receptor. Our mission is to provide an online platform to help students to discuss anything and everything about Zoology. Humans have five senses: hearing, sight, smell, touch and taste. Over 10 million scientific documents at your fingertips. Animals, Biology, Nervous System, Receptors and Sense Organs in Animals, Zoology. Part of Springer Nature. Sense organs are the specialized organs composed of sensory neurons, which help us to perceive and respond to our surroundings. Water is a dense medium and the sound waves moving in water have a greater im­pact. The taste receptors in flies are specific for sugar, water and salts. © 2020 Springer Nature Switzerland AG. But the messages finally transmitted to the brain are different for different tastes. The lateral line canals he in the dermis or deeper and covered by the skin bearing numerous pores. Notably, behaviour can be investigated in the ‘field’ or in the laboratory. Five types of mechanoreceptors are found in vertebrates: The whole body surface forms an organ of touch. They constitute a set of monitoring instruments with which the animal gathers information about itself and its environment. This is a preview of subscription content, https://doi.org/10.1007/978-1-349-02667-8_9. The phonoreceptor or the structure concerned with hearing is inseparable from the inner ear or membranous labyrinth but the latter does not take part in hearing. The recep­tors or the olfactory epithelium (Fig. 14.9C) ramified sensory nerve in a mass of connective tissue, the terminal branches ending in touch cells. Second, an animal has to be able to respond to its environment to survive. Unable to display preview. The capability to detect sound waves at different frequencies varies in different ani­mals. Two types of photoreceptor organs or eyes are found in vertebrates. Rats, weasels, snakes, and centipedes reportedly left their homes and headed for safety several days before a destructive earthquake. C.E. The sense organs for taste are bud-like structures, known as taste buds (Fig. Picture a cat swiveling its ears to capture important sounds without needing to … The impulses are transmitted to the brain and the person becomes conscious of the body position. A single calcareous particle or statolith or a number of small particles, statoconia (Fig. The inverted image is corrected and a direct im­age is formed. Click on the pictures to find out more about each human sense! It is thickest at the posterior end, becomes thinner anteriorly and termi­nates just behind the level of the ciliary body. TOS4. The air being a lighter medium the need to amplify the force of sound waves was a must and this led to the development of new structures. A statocyst is usu­ally an oval sac, may or may not be in com­munication with the exterior and lined inter­nally by a sensory membrane bearing pro- arthropods and molluscs. Hearing, in true sense of the term, is absent in invertebrates. In many air breathing vertebrates (am­phibians, reptiles, mammals) an offshoot of the olfactory organ separated from it, forms a distinct sac lined by sensory epithelium and innervated by the olfactory and trigeminal nerve. Three types of phonoreceptors have been identified in arthropods: The hairs can perceive low frequency vibrations. Privacy Policy3. They can only perceive the disturbances in the medium — air, water or solids. 14.5) is present near the base of the flagellum. The ancestral forms had another type of eye, the median pineal eye, which still persists in cyclostomes and some reptiles. This is the conjunctiva. Three small bones from outer to inside— malleus, incus and stapes, the last one fitting into the fenestra ovalis constitute auditory ossicles. In most cases, they are scattered all over the body. The membranous labyrinth is enclosed in a cavity, the bony labyrinth and bathed in a fluid, the perilymph, which is protective and acts as a buffer. Circular knobs on the fossilized scales look similar to integumentary sense organs (ISOs), which cover the bodies of modern crocodiles. The majority of the fishes having electric organs, however, give off very weak pulses. Atmospheric air pressure on both the sides of the tympanum allows it to vibrate in response to sound waves. A thin mucous membrane, in continuation with the eyelids, is present in front of the cornea. A very small number of nematodes have structures which may play a role in sensitivity to light. 14.8) and compound eyes in crustacea and insects. The antennae and palpi in insects bear receptors for smell. In cnidaria the tactile receptors cnidocils are present (Fig. In Euglena, the photoreceptor, stigma, simply a mass of granules (Fig. a. The taste buds are derived from the epi­thelium and oval in shape. Sense organs that respond to touch and to chemical stimuli play an important role in the behaviour of nematodes, as most of these animals live in the dark in soil, in mud, or in the organs and tissues of other organisms. The ocelli type eyes are constituted by a single ommatidium, as in arachnids (Fig. For example, singing in a crick­et or a bird, where the body works due to the coordination of nerves, muscles and sense organs. The mouth parts and terminal segment of butterflies and moths bear hairs and pegs. Osphradium in molluscs can test the qua­lity of water and it is considered as a chemoreceptor. The animal kingdom doesn't reward the lazy and inattentive. With the change in the body position, the particles exert pres­sure on certain sensory cells and this signals the animal to correct its position with respect to the gravity. These are located within lateral line canals divisible into (a) a trunk and a tail canal and (b) a head or cephalic canal. It is attached to the suspensory liga­ment, the other end of which is continuous with the capsule enclosing the lens. To transfer sound waves from the tympanum to the inner ear, a new structure, as columella anris in amphibians, reptiles and birds and as stapes in mammals was formed from the hyoid arch, which was rendered functionless with the origin of autostyly. Phonoreceptors or sense of hearing can detect pressure waves caused by mechanical disturbances at some distance from the body. The sense of smell (olfactory) and the sense of taste (gustatory) constitute chemorecep­tors. All aspects of an animal's senses, from the structure of its sensory organs to the numbers of receptor cells and the behaviour of its brain, are ultimately derived from its genes. kochlias = snail), an outgrowth of the saccule is a spirally coiled tube of two and half turns. e.g., in the antennae of some insects, particularly warm blood sucking forms. And here is the variation! Odor, color, texture, shape, taste… at each step of the meal, different food attributes stimulate different pets’ organs and senses. Con­traction of the ciliary muscles release the pull on the lens and it thickens and moves forward. In snakes, the thermo receptors are usually located in pits on the sides of the head. A neuromast is a group of sensory cells with supporting cells. The pineal eye of cyclostomes can possi­bly distinguish light and darkness. Horses’ ears can move 180 degrees using 10 different muscles (compared to three muscles for the human ear) and are able to single out a specific a… It is 20 to 20,000 hertz in man, over 100,000 in bats. The stapes and a fine sheet of fibrous tissue occlude the fenestra ovalis and the fenestra cochlea, respectively. Subscription content, https: //doi.org/10.1007/978-1-349-02667-8_9 removal of both the eyes by surgery are usually scattered over. Fibres constitute the organ of sound waves a complete history of transformation of eyes. Caused by mechanical disturbances at some distance from the ciliary muscle and known as tymponal organ the..., water or solids cells sensitive to temperature variations are present in.! Eyes of cephalopods are camera type like those of planaria and leech are internal receptor sense organs and behaviour of animals present in planaria Fig... 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