Basic Histology Quiz- Muscle Created by: Maureen Bain Start

Question 1 What type of muscle fibres are represented in these two figures? What criteria did you use to come to this conclusion? What name is given to the connective tissue component of muscle labeled A and B (see -low power view)? What role's do these connective tissue components play? Answers at end of Quiz BackNext Skeletal muscle in transverse section

Question 2 Skeletal muscle type in longitudinal section Answers at end of Quiz BackNext What gives rise to the visible striations in skeletal muscle? What is the special name given to the contractile units associated with skeletal muscle? What type of protein is associated with the thin and thick myofilaments associated with these contractile units? What is the function of the T-tubule system in skeletal muscle? What functional role does the Sarcoplasmic reticulum play during muscle contraction and relaxation ?

Question 2 This image shows a transverse section of the descending colon (dog) which is part of the large intestine. What type of epithelium lines the lumen of this tubular structure? What do you think cell type A represents? Descending colon (low power) lumen Digesta in lumen epithelium A CT= connective tissue Answers at end of Quiz BackNext

Question 3 What type of muscle is represented in the high power image? What other criteria did you use to come to this conclusion? How does the wave of depolarization travel between individual smooth muscle cells? Answers at end of Quiz BackNext Descending colon (low power)

Question 4 In the centre of this image there is a section (TS) through an artery. A = the lumen and tm is the muscular tunic which forms part of the wall of this vessel. What type of muscle forms the muscular tunic of this vessel? What type of epithelium lines the lumen of this vessel? Answers at end of Quiz BackNext tmA Small muscular artery in transverse section

Question 5 These images show cardiac muscle sectioned longitudinally (LS) stained with different histological stains. Phosphotungstic acid haematoxylin (PAH) is good for showing up the positions of the intercalated discs. List the characteristic features of this type of muscle as it appears in LS. How would you distinguish between cardiac and smooth muscle in images where the muscle is presented in TS? ID = an intercalated disc. What is an intercalated disc ? What is the function of intercalated discs? Answers at end of Quiz BackNext H&E PAH ID

Answers 1. Skeletal Peripheral multiple nuclei (LS and TS), extremely long parallel individual fibres(LS), striations (LS) A= Perimysium. B= Endomysium Blood vessels and nerves. Also provide something for muscle fibres to ‘work against’. 2. Alignment of contractile units within myofibrils, which are all in register with one another within each myocyte (muscle fibre). Sarcomere Actin and Myosin Spread of wave of depolarisation caused by action potential causing Sarcoplasmic reticulum to release Calcium. Calcium release and then active uptake. 3. Simple columnar epithelium Goblet cell Smooth Central nucleus in TS, Different size of fibre in TS may without a nucleus, Tapering cells which wrap around each other (LS), No striations (LS). Via gap junctions between the individual cells- allows rapid communication. 4. Smooth Simple squamous 5. Short broad branched fibres with central nucleus, striations and intercalated discs. There also tends to be more endomysium between the individual muscle fibres. Both have central nucleus, but in smooth muscle fewer of the TS sections will have a nucleus visible. The sectioned fibres will be of a more uniform size and there will be more endomysium surrounding each fibre in the case of cardiac muscle. Note: the presence of striations and intercalated discs are only discernable in LS. Junctional complex- adhesion (tight junctions) and communication (Gap). Spread of wave of depolarisation. Back to quiz