Presentation on theme: "Memmler’s Structure and Function of the Human Body 9th edition"— Presentation transcript:
1 Memmler’s Structure and Function of the Human Body 9th edition Chapter 10The Sensory System
2 The Senses Sensory system detects environmental change Environmental change initiates nerve impulse (stimulus)Stimulus interpreted by cerebral cortexSensation experienced
3 Sensory Receptors Classifying sensory receptors Structure Free dendrite of sensory neuronEnd-organ on dendrite of afferent neuronSpecialized cell associated with afferent neuronType of stimulusChemoreceptorsPhotoreceptorsThermoreceptorsMechanoreceptors
4 Sensory Receptors Sensory receptors Distribution of sense receptorsSpecial senses in sense organVisionHearingEquilibriumTasteSmellGeneral senses throughout bodyPressure, temperature, pain, touchSense of positionSensory receptorsChemoreceptors- respond to chemicalsPhotoreceptors-respond to lightThermoreceptors- respond to heatMechanoreceptors- respond to movement
5 Question: Which sensory receptors respond to movement. a Question: Which sensory receptors respond to movement? a. thermoreceptors b. photoreceptors c. mechanoreceptors
18 Function of the Retina Pigmented layer Sensitive to light Rods Function in dim lightShades of grayBlurred imagesConesFunction in bright lightColor sensitiveSharp imagesConnecting neurons
19 Checkpoint 10-4: What are the receptor cells of the retina?
20 Structure of the retina Structure of the retina. Rods and cones form a deep layer of the retina, near the choroid. Connecting neurons carry visual impulses toward the optic nerve.
21 The fundus (back) of the eye as seen through an ophthalmoscope.
22 Muscles of the EyeTwo muscle groups adjust eye so retina can receive clear image
23 The Extrinsic Muscles Outer surface of eyeball Voluntary Control convergence for three-dimensional vision
24 Extrinsic muscles of the eye. The medial rectus is not shown. ZOOMING IN • What characteristics are used in naming the extrinsic eye muscles?
25 Checkpoint 10-5: What is the function of the extrinsic muscles of the eye?
26 The Intrinsic Muscles Within eyeball Iris regulates amount of light entering eyeCiliary muscle shapes lens for near and far vision
27 Function of the iris.ZOOMING IN • What muscles of the iris contract to make the pupil smaller? Larger?
28 The ciliary muscle and lens (posterior view) The ciliary muscle and lens (posterior view). Contraction of the ciliary muscle relaxes tension on the suspensory ligaments, allowing the lens to become more round for near vision. ZOOMING IN• What structures hold the lens in place?
30 Checkpoint 10-6: What is the function of the iris? Checkpoint 10-7: What is the function of the ciliary muscle?
31 Nerve Supply to the Eye Optic nerve (cranial nerve II) Ophthalmic branch of trigeminal nerve (cranial nerve V)Oculomotor nerve (cranial nerve III)Trochlear (cranial nerve IV)Abducens (cranial nerve VI)
32 Nerves of the eye. ZOOMING IN• Which of the nerves shown moves the eye?
33 Checkpoint 10-8: What is cranial nerve II and what does it do?
34 The Ear Sense organ for hearing and equilibrium Outer ear Middle ear Inner ear
35 The ear. Structures in the outer, middle, and inner divisions are shown
36 The Outer Ear Pinna (auricle) Directs sound waves into ear External auditory canal (meatus)Ceruminous glandsTympanic membraneVibrates as sound waves enter ear
37 Question: What is the anatomic name for the external part of the ear Question: What is the anatomic name for the external part of the ear? (that funny-looking curved part that sticks out from the side of your head) a. malleus b. meatus c. pinna
48 Checkpoint 10-10: What is the name of the organ of hearing and where is it located?
49 EquilibriumCiliated equilibrium sensory receptors are located in vestibule and semicircular canalsTypes of equilibriumStaticVestibuleMaculae—receptorsOtoliths fluidDynamicSemicircular canalsCristae receptors
50 Action of the receptors (maculae) for static equilibrium. ZOOMING IN • What happens to the cilia on the receptor cells when the fluid around them moves?
51 Action of the receptors (cristae) for dynamic equilibrium.
52 Checkpoint 10-11: Where are the receptors for equilibrium located? Checkpoint 10-12: What are the two types of equilibrium?
53 Other Special Sense Organs Taste and smell sense organs respond to chemical stimuli
54 Sense of Taste Taste receptors (buds) on tongue Stimulated by substance in solutionBasic tastesSweetSaltySourBitterOther tastesWaterAlkalineMetallicUmamiCranial nervesFacial (VII)Glossopharyngeal (IX)
55 Special senses that respond to chemicals. Organs of taste (gustation) and smell (olfaction).(B) A taste map of the tongue.
56 Sense of Smell Smell receptors in nasal cavity Stimulated by substances in solution in nasal fluidsSmells stimulate appetite and flow of digestive juicesOlfactory nerve (cranial nerve I)
57 Checkpoint 10-13: What are the special senses that respond to chemical stimuli?
58 The General Senses Receptors scattered throughout the body sense Touch PressureHeatColdPositionPain
60 Sense of Touch Sense of Pressure Tactile corpuscles Found mostly in dermis of skin and around hair folliclesSensitivity varies with the number of receptorsBaroreceptors in walls of large arteries monitor blood pressure and trigger responses that control BP as vessels stretch.Sense of PressureReceptors for deep touch locatedIn subcutaneous tissuesNear joints, muscles, and other deep tissues
61 Sense of Temperature Temperature receptors Are free nerve endings Are widely distributed in the skinAre separate for heat and coldOccur in hypothalamus of brainHelp to adjust body temperature according to temperature of circulating blood
62 Sense of Position Proprioceptors (position receptors) Are located in muscles, tendons, jointsRelay impulses of body parts in relation to each otherSend impulses to the cerebellum for coordination
63 Checkpoint 10-14: What are examples of general senses? Checkpoint 10-15: What are proprioceptors and where are they located?
64 Question: Temperature receptors in what part of the brain regulate body temperature according to circulating blood temperature? a. hypothalamus b. medulla oblongata c. cerebral cortex
66 Sense of Pain Pain receptors Are free nerve endings Are found in skin, muscles, joints and (to a lesser extent) in most internal organsPain reliefAnalgesic drugsAnestheticsEndorphinsHeat or coldRelaxation or distraction techniques
67 Sensory AdaptationOccurs when receptors are exposed to continuous stimulusSome receptors can adjust themselves so sensation becomes less acuteReceptors adapt at different ratesPain receptors do not adapt