PN 141 Neurosensory Nursing Care

1. PN 141 Neurosensory Nursing Care

2. Day 1 Objectives • List major sense organs and their anatomical position • List the parts of the eye and the function of each part • List the three divisions of the ear and discuss the function of each • Discuss age related changes of the sensory system and the differences of assessment findings • Discuss the purpose, significant results of, and nursing responsibilities related to diagnostic testing of the visual and auditory systems

3. Overview • The sensory system: • gathers information from receptors throughout the body • delivers it to the brain for interpretation. • The five major senses are: taste, touch, smell, sight, and hearing. • The sense of balance is linked with hearing because the sensors are located within the ear.

4. Sensory System • Special and General Senses • General Senses: • Pressure • Temperature • Pain • Touch • Position • Can experience alteration in any of these senses.

5. Sensory System • Sense of position (proprioception) • Proprioceptors = any sensory nerve ending • Respond to stimuli originating from within the body re: movement and spatial perception • Work in conjunction with the inner ear

6. Sensory System • Taste • Taste buds are receptor for 4 basic sensations: • Sweet • Sour • Salty • Bitter • See tongue map

7. Special senses that respond to chemicals. (A) Organs of taste (gustation) and smell (olfaction). (B) A taste map of the tongue.

8. Sensory System • Smell – olfactory receptors • Located in the roof of the mouth or the upper part of the nasal cavity • Memory for certain smells is long-standing • Olfactory cells cannot be regenerated

9. Sensory System • How does it work? • Sensory system detects environmental change  • Environmental change initiates nerve impulse (stimulus)  • Stimulus interpreted by cerebral cortex (brain) --. • Sensation experienced

10. SENSORY DEFICIT • A change in the perception of sensory stimuli, can affect all five senses. • Sensory deprivation–state of reduced sensory input from internal or external environment. • Sensory overload–state of excessive and sustained multi-sensory stimulation.

11. Classifying Sensory Receptors • Classified according to the type of stimulus to which they respond: • Chemoreceptors (chemicals – taste, smell) • Photorecptors (light) • Thermoreceptors (temperature) • Mechanorecptors (pressure • Proprioreceptors (position)

12. The Eye and Vision

13. The Eye and Vision • The adult eye is approx. 1” • Eye protection structures • Eye cavity bones • Frontal • Zygomatic • Ethmoid • Sphenoid • Lacrimal

14. The Eye and Vision • Accessory structures that function as protective devices: • Eyelids • Eyelashes and eyebrow • Lacrimal glands (produce tears-salt, mucous, and bacteriocidal enzyme called lysozyme) • Conjunctiva (mucous membrane)

15. The Eye and Vision • Lacrimal Apparatus • Manufactures and drains tears • To keep the eyeball moist • To sweep away debris

16. Figure 13-1 (From Thibodeau, G.A., Patton, K.T. [2003]. Anatomy and physiology. [5th ed.]. St. Louis: Mosby.) Lacrimal apparatus.

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

18. Overview of Anatomy and Physiology • Structures of the eyeball • Sclera (white): connective tissue, thick, fibrous • Gives shape, protects inner eye structures • Cornea: central anterior portion of the sclera • Covers the iris; allows light rays to enter the inner portion of the eye

19. Overview Anatomy and Physiology • Structures of the eyeball cont. • Choroid: Thin dark brown membrane that lines most of the internal area of sclera • Vascular • Supplies nutrients to the retina • Ciliary body: intrinsic muscular ring; holds lens in place; changes shape for near and distant vision

20. Overview Anatomy and Physiology • Structures of the eyeball cont. • Iris: • The colored portion of the eye • Lies between the cornea and lens • regulates the amount of light entering through the pupil • Pupil: circular, central opening of the Iris

21. Overview Anatomy and Physiology • Retina: Received images of external objects transmits impulses through the optic nerve the brain • Contains Rods and Cones: receptor cells of the body

22. Overview Anatomy and Physiology • Rods: Function in dim light – contain receptors for night vision and peripheral vision • Provide blurred images • Cones: Function in bright light • Responsible for day vision • Color sensitive (red, green, blue cones) • Provide sharp images

23. Overview Anatomy and Physiology • Structures of the eyeball cont. • Conjunctiva: thin mucous membrane that lines the inner aspect of eyelids and anterior surface of the eyeball edge of the cornea

24. Overview Anatomy and Physiology • Eyeball has three separate coats (tunics) • Sclera • Choroid • Retina • Chambers of the eye: • Anterior: Crystalline Lens • Aqueous Humor

25. Overview Anatomy and Physiology • Crystalline Lens: transparent, colorless Function: focus light rays so that they form a perfect image on the retina • Held in place behind the pupil by suspensory ligaments • Aqueous Humor: clear watery fluid • Constantly formed, drained, and replaced to maintain normal intraocular pressure • Also helps to maintain eyeball shape, keep the retina attached, and refract light

26. Overview Anatomy and Physiology • Posterior Chamber: filled with: • Vitreous Humor: • transparent jellylike substance • Gives shape • Keeps the retina attached Refracts light • Fluid/jellylike substance not continually replaced

27. Pathway of Light Rays and Refraction • Transparent parts of the eye: • Cornea • Aqueous Humor • Pupil • Crystalline Lens • Vitreous body • Rods/Cones • The transparent parts change the direction of light rays as they enter the eye.

28. Overview A&P • Intrinsic Eye Muscles • Within the eye • Form the Iris and Ciliary muscle • Extrinsic Eye Muscles: 6

29. Extrinsic muscles of the eye. The medial rectus is not shown.  

30. Nerve Supply to the Eye • Optic Nerve (Cranial Nerve II) • Transmits impulses from the retina thalamus of the brain directed to the occipital cortex

31. Visual Pathway Steps to vision: Light refracts (bends) Muscles of the Iris adjust the pupil Ciliary muscle adjusts the lens (accommodation) Extrinsic eye muscles produce convergence Light stimulates retinal receptor cells (rods and cones) Optic nerve transmits impulses to brain Occipital lobe cortex interprets the impulses

32. Nursing Implications,Considerations and Responsibilities

33. Age-Related Changes in the Eye Skin around the eye becomes wrinkled and loose Eyelids usually have some excess tissue; not important unless it interferes with vision The amount of fat around the eye decreases, permitting the eyeball to sink deeper into the orbit Tear secretion diminishes; cornea less sensitive Grayish ring may be around the outer margin of the iris

34. Age-Related Changes in the Eye • Pupil: smaller and responds more slowly to light; need for brighter light • Presbyopia: ability to focus is impaired for “near” objects • Crystalline Lens: • hardens, becomes too large for the eye muscles loss of accommodation (need for bi- and trifocal lens) • Loses some transparency opaque; glare becomes a problem

35. Health History History of present illness Record changes in vision If pain, inquire about location and nature Sensitivity to light (photophobia) Discharge from the eyes Complaints that the eyes feel dry and irritated Past medical history Diabetes, neurologic disorders, thyroid disease, hypertension

36. Health History Family history Any eye diseases as well as a history of arteriosclerosis, diabetes, and thyroid disease Functional assessment Patient’s occupation, roles, usual activities

37. Sensory ASSESSMENT Focuses specifically on the client’s ability to: • Hear • See • Taste • Smell • Touch

38. Physical Examination Inspect the external eye, assess response of the pupil to light, and evaluate gross visual acuity If abnormalities suspected, inform physician or advise patient to seek medical evaluation Acuity commonly tested with Snellen chart

39. Diagnostic Tests and Procedures Ophthalmoscopic examination – examines the underlying structure of the eye (Mydriatic drops dilate pupil) Refractometry – optometry/opthalmascopy asks patients to indicate “clear” or blurred vision with each lens Tonometry – measures intraocular pressure

40. Diagnostic Tests and Procedures • Visual fields – e.g. Tangent Screening • Evaluates the central and peripheral fields • (handout) • Fluorescein angiography • Examines microvascular structures; assesses patency of lacrimal system; assesses for corneal abrasion

41. Diagnostic Tests and Procedures • Corneal staining – looking for abrasion/infection • Slit Lamp Exam – examines conjunctiva, lens, vitreous humor, iris, cornea • Imaging procedures • CT, ultrasonography, radioisotope scanning, or MRI

43. Laboratory and Diagnostic Examinations • Diagnostic eye tests • Snellen test (visual acuity) • Color vision – Ishihara test • Ophthalmoscopy • Tonometry • Amsler grid test (dx./monitor macular problems) • Schirmer’s tear test (measures tear volume) • Table 13-2. pp. 608, 609 AHN

44. Figure 51-5

45. Figure 51-6

46. Tonometry

47. Ishihara Chart

48. Amsler Grid

49. The Ear

50. The ear. Structures in the outer, middle, and inner divisions are shown.