Musculo Skeletal System Flashcards
Describe the structure of skeletal muscle. (Each layer, vascularization, innervation, attachments)
Myofibril–>Muscle fiber–>Fascicle–>Muscle
Highly vascularized and innervated.
Attached to bone by tendons.
Myofibers. Innervated? Job? Attachment/s?
Innervated by motor nerves that cause contraction. Attached to tendons at the myotendinous junction.
Satellite cells
“Stem cells”. Essential for muscular regeneration. Between basal lamina and sarcolemma.
Define sarcolemma
Membrane around each myofiber. “Houses” satellite cells required for regeneration.
Phases of muscle injury?
- Initial damage.
- Formation of hematoma
- Influx of WBC (leukocytes), phagocytosis
Compare “strain” and “sprain”
Sprain- injury to ligaments around joints.
Sprain- Injury to muscles or tendons
What limits muscle shearing during/after injury?
Contraction bands inside myofibril
Which layer is “key” in muscle restoration and healing?
Basal lamina
Stages of muscle healing
- Hemostasis- Hematoma is formed. 24-48 hrs post injury
- Proliferation- After phagocytosis satellite cell and myofibril regeneration. 6-8weeks
- Maturation- Tissue remodeling
Muscle fiber types
Type I-Slow twitch. Very resistant to fatigue
Type IIa- Fast twitch, moderately resistant to fatigue
Type IIb- Fast twitch, not resistant to fatigue.
Degrees of strains
1st- Minor tearing of a few fibers
2nd- Moderate tearing with some loss of function
3rd- Complete tear through muscle unit (either muscle or tendon) with complete loss of function
Define “Osteomalacia”
Soft bone. Known in children as “Rickets”
Cause of Osteomalacia
Lack of Ca+, Vit D, Phosphate. Decreased mineralization at growth plates.
Define Paget’s Dz
Excessive bone growth. S/S pain and stiffness, Fatigue, HA/dizziness, deformity.
T/F Paget’s affects flat bones more than long bones?
False. Affects both but affects long bones more than flat bones
Rickets causes Genu varum or genu valga?
Genu verum.
Pathogenosis of Paget’s?
Old bone breaks down faster. Body responds by building bone faster than normal. Leads to deformity of bones/joints.
Circulatory Dz’s of bone
Aspetic Necrosis.
Legg Calve Pethes.
Osgood Schlatter.