Histology of MSK Flashcards
Skeletal muscle fibres are striated, branched and mononucleate - true/false
False - striated, unbranched and multinucleate
Nuclei are found where in skeletal muscle fibres (cells)
At the periphery just below the sarcolemma.
Why are nuclei found in the periphery/corners of skeletal muscle fibres?
The cells are so densely packed with contractile proteins it is hard to find room for the nuclei
Muscle fibres are grouped together in bundles called _____
Fascicles
the thick connective tissue surrounding the whole muscle is called the epimysium/perimysium/endomysium
the epimyscium
Each fascicle is surrounded by a piece of connective tissue called the epimysium/perimysium/endomysium
perimysium
Each muscle fibre is surrounded by a piece of connective tissue called the epimysium/perimysium/endomysium
endomysium
Thousands of sarcomeres attached end to end make up a fibre and many fibres are packed parallel to each other into a myofibril. True/false
False
Thousands of sarcomeres attached end to end make up a myofibril and many myofibrils are packed parallel to each other into a Fibre - like a cigarette packet.
The actin filaments are anchored at which part of the sarcomere?
The z-line
What is a motor unit?
One alpha motor neurone and all the muscle fibres it innervates
The fibres in a motor unit are all bunched together and are all of the same fibre type - true/false
False - the fibres in a motor unit are all scattered in the muscle and are all of the same fibre type
What are the there fibre types in skeletal muscle?
Type I - relatively slow contracting fibres, rely on aerobic metabolism. abundance of mitochondria resistant to fatigue, produce less force. often called “red fibres.”
Type IIA - intermediate and relatively fast to contract also reasonably resistant to fatigue. reasonably uncommon.
Type IIB -fast contracting fibres rely on anaerobic metabolism, few mitochondria, fatigue easily and produce greater force. often called “white fibres.”
Cartilage is avascular - True/false
True
How does cartilage get its nutrition?
From the extracellular matrix via diffusion
What is the name of the cells in cartilage?
Chondrocytes (chondroblasts if immature)
Chondrocytes live in a cave like area of the extracellular matrix - what is this called?
the lacuna.
75% of the extracellular matrix is water. the other 25% is organic matter containing _____ and _____.
Collagen type II and proteoglycan aggregates.
What is the difference between collagen type I and type II?
Collagen II is finer and forms a 3D meshwork while collagen I is thicker and forms a 2D linear structure.
Name the three types of cartilage
Which is most common?
Hyaline - most common
Elastic
Fibrocartilage
Describe hyaline cartilage
Glassy - blue/white colour - most common form
Describe elastic cartilage
Light yellow - flexible due to elastin fibres
Describe fibrocartilage
Hybrid between tendon and hyaline cartilage. White - contains lots of type I collagen.
Bone is composed of live cells and therefore is vascular true/false
True
What percentage of all the calcium stored in the body is stored by/in bone?
95%
