What biochemical markers indicate damage to muscle integrity?
Creatinine kinase (CK)
Aspartate amiotransferase (AST)
Why is the release of myoglobin bad for animals?
Myoglobin is nephrotoxic so damage to the kidneys can further compromise the animals
How are do you prepare a section of skeletal muscle for histological examination?
Undermine and clamp before incisions, fix, and release once fixed.
What causes the onset and then resolution of rigor mortis?
Onset - ATP depletion
Resolution - protein degredation
What factors can affect the colour of skeletal muscle on PM examination?
Necrosis causes pale muscle
Age - younger animals tend to have paler muscle
Species - e.g. pork is a different colour to beef
Other pathology e.g. anaemia
Inflammation or haemorrhage causes red muscle
What is the smallest unit of skeletal muscle?
What is the difference between type I and type II skeletal muscle fibres?
Type I skeletal muscle fibres are slow response, slow fatigue, use oxidative (aerobic metabolism), are postural muscles and 'red' muscle
Type II skeletal muscles are fast response, fast fatigue, glycolytic (anaerobic) metabolism, propulsive muscles, 'white' muscle
What does skeletal muscle look like on longitudinal and transverse histological section?
Longitudinal - broad stripes of myofibres that contain fibrils. These are surrounded by basal laminae and CT. Cells are very long, have multiple nuclei distributed along the length of the cell.
Transverse - endomysium surrounding each fibre stretching out to the perimysium, nuclei are at the edges of the cells
True or false: muscle cells have the ability to enter the cell cycle?
False - muscle cells are permanent cells and have no capacity to enter the cell cycle/divide
Describe what happens to muscle cells after they are injured, depending on whether the basal laminae is intact or destroyed
Basal laminae intact - macrophages enter and remove debris, satellite cells become myoblasts, myoblasts fuse to form myotubules, essential structures reformed, nuclei move to peripheral position - REGENERATION