Chapter 8 The Musculoskeletal System

1. Chapter 8The Musculoskeletal System

2. Osteoporosis • is a metabolic bone disease characterized by a severe reduction in bone density; easy bone fracture. • occurs when the rate of bone resorption greatly exceeds the rate of bone formation. • Causes of Osteoporosis • The rate of bone formation decreases with age.

3. Osteomalacia and Rickets • Osteomalaciais a metabolic bone disease seen in adults, caused by decreased mineralization of the bone as a result of a deficiency of calcium, phosphate, or both leading to soft, flexible bone. • Usually, it results from a vitamin D deficiency or from renal disease. • Ricketsis a bone disease in children caused by vitamin D deficiency. • Clinical Manifestations: • Osteomalaciamay be symptomless until a fracture occurs. Vertebral collapse is common, with associated changes in posture and height. • Rickets is characterized by permanent skeletal deformity (bowed legs, lumbar lordosis, and rib and skull deformity) • . Children may be unable to walk without support. They may also show poor dentition. Diagnostic Tools • - X ray. • - Measurements of serum calcium and phosphate

4. Chapter 9The senses

5. Pathophysiologic Concepts • Amblyopia • The loss of visual acuity in an eye that appears to be structurally intact, the central nervous system becomes unable to identify visual stimuli. • Strabismus • Deviation in the position of the eyes relative to each other. With strabismus, the eyes may appear to be crossed. An individual who has strabismus often complains of double vision. • Nystagmus • The involuntary, rhythmic movement of one or both eyes is called nystagmus. The movement may be jerking, rotating, or pendular.

6. Myopia • Nearsightedness, occurs when the eye is unable to accommodate sufficiently to objects that are far away. • Hyperopia • Farsightedness; the eye is unable to accommodate sufficiently to close objects • Hyperopia may be present early in life or may develop later, typically after the fourth decade of life (presbyopia). • Astigmatism • In astigmatism, light rays are scattered rather than focused on the retina because of an asymmetric curvature of the cornea. • The image is distorted or blurred. • Astigmatism may occur with myopia or hyperopia.

7. Papilledema • Swelling of the optic disk where the optic nerve leaves the eye and enters the brain. • It can occur in any condition that causes severely increased intracranial pressure (brain tumor, infection, or injury) • Papilledema is often an important diagnostic clue in severe brain pathology.

8. Conductive Hearing Loss • Decrease in hearing caused by a blockage in the conduction of sound waves in the external or middle ear. • It may occur if a foreign object is present in the ear or if there is an excessive wax or fluid buildup in the external or middle ear. • Recurrent otitis media may cause conductive hearing loss. A hearing aid may offer improvement. • Sensorineural Hearing Loss • Sensorineural hearing loss is a decrease in hearing caused by dysfunction of the organ of Corti, the auditory nerve, or the brain.

9. Conductive Hearing Loss • Is a decrease in hearing caused by a blockage in the conduction of sound waves in the external or middle ear. • Causes: • a foreign object is present in the ear, excessive wax or fluid buildup in the external or middle ear. • Recurrent otitis media may cause conductive hearing loss. A hearing aid may offer improvement.

10. Sensorineural Hearing Loss • Sensorineural hearing loss is a decrease in hearing caused by dysfunction of the organ of Corti, the auditory nerve, or the brain. • Tinnitus • Described as a ringing in one or both ears, tinnitus may accompany ear wax buildup or presbycusis. • Aspirin overdose or other drugs may induce tinnitus. Middle-ear infection, or otosclerosis (irregular ossification of middle-ear bones) may also cause tinnitus.

11. Vertigo • The sensation of motion or spinning, often described as a feeling of being off balance, is called vertigo. • Vertigo is sometimes accompanied by nausea, weakness, and mental confusion. • Inner-ear inflammation, especially of the semicircular canals, is the most common cause of vertigo

12. Conditions of Disease or Injury • Conjunctivitis • Inflammation of the conjunctiva of the eye caused by an infectious process, physical irritation, or an allergic response is known as conjunctivitis. With inflammation, the conjunctiva becomes red, swollen, and tender. Conjunctivitis stemming from a bacterial infection is sometimes called pink eye.

13. Otitis • Otitis is an inflammation of the ear. Inflammation may be of the external ear canal, called otitisexterna, or of the middle ear, called otitis media.