Developmental Aspects of Muscular System

Development Embryo Muscular system laid down in segments Each segment is invaded by nerves First movements of fetus Occur by 16th week of pregnancy

Muscle Development Once born, a baby’s movements are all gross reflex types of movements Nervous system must mature Control proceeds in cephalic/caudal direction Gross muscular movements precede fine ones Ex: babies can raise head before they sit up; Wave ‘bye’ before grasping blocks

Healthy Muscles Rich blood supply Resistant to infection Good nutrition Regular exercise If not, then atrophy

Aging As we age, amount of connective tissue increases Amount of muscle tissue decreases So what? Body weight declines Decrease in muscle strength

Muscle Problem Examples Muscular dystrophy Myasthenia gravis Torticollus

Muscular dystrophy A group of genetic muscle diseases that cause progressive muscle weakness Muscles enlarge due to fat and connective tissue deposit Muscle fibers degenerate

Duchenne MD Mostly in boys (X-linked recessive) Diagnosed between 2-7 years old Active, normal children appear clumsy Disease progresses from extremities upward Usually results in death due to respiratory distress

Myasthenia gravis Symptoms include: Drooping of upper eyelids Difficulty swallowing and talking Muscle fatigue and weakness Shortage of Acetylcholine receptors at neuromuscular junctions Muscles not stimulated properly Death usually occurs due to respiratory failure

Torticollis ‘Wry neck’ In difficult births, one of sternocleidomastoid muscles may be injured Muscles contract involuntarily Cause head to turn

Topics in Muscles You and a partner will be assigned a muscle disease or disorder. Research the topic. Outline 5 major/interesting findings (including cause, symptoms & treatment) as they pertain to our study of the muscular system. Try to include any recent breakthroughs. Present information (informally as roundtable) to the class about your topic.

Topics in Muscles 1. Dermatomyositis 2. Compartment Syndrome 3. Rhabdomyolysis 4. Myopathy 5. Diastasis Recti 6. Zenker ’ s Degeneration 7. Pelvic Floor Muscle Disorder 8. Fibromyalgia 9. Tetanus 10. Botulism 11. Orofacial Myology Disorders