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Memmler’s Structure and Function of the Human Body 9th edition

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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 10 The Sensory System

2 The Senses Sensory system detects environmental change
Environmental change initiates nerve impulse (stimulus) Stimulus interpreted by cerebral cortex Sensation experienced

3 Sensory Receptors Classifying sensory receptors Structure
Free dendrite of sensory neuron End-organ on dendrite of afferent neuron Specialized cell associated with afferent neuron Type of stimulus Chemoreceptors Photoreceptors Thermoreceptors Mechanoreceptors

4 Sensory Receptors Sensory receptors
Distribution of sense receptors Special senses in sense organ Vision Hearing Equilibrium Taste Smell General senses throughout body Pressure, temperature, pain, touch Sense of position Sensory receptors Chemoreceptors- respond to chemicals Photoreceptors-respond to light Thermoreceptors- respond to heat Mechanoreceptors- 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

6 Answer: c. mechanoreceptors

7 The Eye and Vision Eye protection structures Eye cavity bones Eyelids
Eyelashes and eyebrow Conjunctiva Lacrimal glands

8 Protective structures of the eye.

9 The lacrimal apparatus.

10 Checkpoint 10-1: What are some structures that protect the eye?

11 Coats of the Eyeball Eyeball has three separate coats (tunics) Sclera
Choroid Retina

12 The eye. Note the three tunics, the refractive parts of the eye (cornea, aqueous humor, lens, vitreous body), and other structures involved in vision.

13 Checkpoint 10-2: What are the names of the tunics of the eyeball?

14 Pathway of Light Rays and Refraction
Transparent parts of the eye that refract light Cornea Aqueous humor Crystalline lens Vitreous body

15 Checkpoint 10-3: What are the structures that refract light as it passes through the eye?

16 Question: What is the name of the fluid within the eyeball. a
Question: What is the name of the fluid within the eyeball? a. aqueous humor b. vitreous c. sclera

17 Answer: a. aqueous humor

18 Function of the Retina Pigmented layer Sensitive to light Rods
Function in dim light Shades of gray Blurred images Cones Function in bright light Color sensitive Sharp images Connecting 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 Eye Two 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 eye Ciliary 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?

29 Accommodation for near vision.

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 glands Tympanic membrane Vibrates 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

38 Answer: c. pinna

39 The Middle Ear and Ossicles
Middle ear cavity contains ossicles (small bones) that amplify sound waves and transmit sounds to inner ear Malleus (hammer) Incus (anvil) Stapes (stirrup)

40 Checkpoint 10-9: What are the ossicles of the ear and what do they do?

41 Eustachian Tube Connects middle ear cavity with throat (pharynx)
Allows pressure to equalize on both sides of tympanic membrane Continuous mucous membrane from pharynx to middle ear cavity

42 The Inner Ear Bony labyrinth Vestibule Semicircular canals Cochlea
Perilymph fluid Membranous labyrinth Endolymph fluid

43 The inner ear.

44 Hearing Organ of Corti Located in membranous cochlea (cochlear duct)
Ciliated receptor cells Tectorial membrane

45 Question: True or False: The cochlea is in the middle ear.

46 Answer: False: The cochlea is in the inner ear.

47 Cochlea and the organ of Corti.

48 Checkpoint 10-10: What is the name of the organ of hearing and where is it located?

49 Equilibrium Ciliated equilibrium sensory receptors are located in vestibule and semicircular canals Types of equilibrium Static Vestibule Maculae—receptors Otoliths fluid Dynamic Semicircular canals Cristae 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 solution Basic tastes Sweet Salty Sour Bitter Other tastes Water Alkaline Metallic Umami Cranial nerves Facial (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 fluids Smells stimulate appetite and flow of digestive juices Olfactory 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
Pressure Heat Cold Position Pain

59 Sensory receptors in the skin.

60 Sense of Touch Sense of Pressure Tactile corpuscles
Found mostly in dermis of skin and around hair follicles Sensitivity varies with the number of receptors Baroreceptors in walls of large arteries monitor blood pressure and trigger responses that control BP as vessels stretch. Sense of Pressure Receptors for deep touch located In subcutaneous tissues Near joints, muscles, and other deep tissues

61 Sense of Temperature Temperature receptors Are free nerve endings
Are widely distributed in the skin Are separate for heat and cold Occur in hypothalamus of brain Help to adjust body temperature according to temperature of circulating blood

62 Sense of Position Proprioceptors (position receptors)
Are located in muscles, tendons, joints Relay impulses of body parts in relation to each other Send 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

65 Answer: a. hypothalamus

66 Sense of Pain Pain receptors Are free nerve endings
Are found in skin, muscles, joints and (to a lesser extent) in most internal organs Pain relief Analgesic drugs Anesthetics Endorphins Heat or cold Relaxation or distraction techniques

67 Sensory Adaptation Occurs when receptors are exposed to continuous stimulus Some receptors can adjust themselves so sensation becomes less acute Receptors adapt at different rates Pain receptors do not adapt

68 End of Presentation

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