Histology of MSK

Question 1

Skeletal muscle fibres are striated, branched and mononucleate - true/false

Answer 1

False - striated, unbranched and multinucleate

Question 2

Nuclei are found where in skeletal muscle fibres (cells)

Answer 2

At the periphery just below the sarcolemma.

Question 3

Why are nuclei found in the periphery/corners of skeletal muscle fibres?

Answer 3

The cells are so densely packed with contractile proteins it is hard to find room for the nuclei

Question 4

Muscle fibres are grouped together in bundles called _____

Answer 4

Fascicles

Question 5

the thick connective tissue surrounding the whole muscle is called the epimysium/perimysium/endomysium

Answer 5

the epimyscium

Question 6

Each fascicle is surrounded by a piece of connective tissue called the epimysium/perimysium/endomysium

Answer 6

perimysium

Question 7

Each muscle fibre is surrounded by a piece of connective tissue called the epimysium/perimysium/endomysium

Answer 7

endomysium

Question 8

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

Answer 8

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.

Question 9

The actin filaments are anchored at which part of the sarcomere?

Answer 9

The z-line

Question 10

What is a motor unit?

Answer 10

One alpha motor neurone and all the muscle fibres it innervates

Question 11

The fibres in a motor unit are all bunched together and are all of the same fibre type - true/false

Answer 11

False - the fibres in a motor unit are all scattered in the muscle and are all of the same fibre type

Question 12

What are the there fibre types in skeletal muscle?

Answer 12

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.”

Question 13

Cartilage is avascular - True/false

Answer 13

True

Question 14

How does cartilage get its nutrition?

Answer 14

From the extracellular matrix via diffusion

Question 15

What is the name of the cells in cartilage?

Answer 15

Chondrocytes (chondroblasts if immature)

Question 16

Chondrocytes live in a cave like area of the extracellular matrix - what is this called?

Answer 16

the lacuna.

Question 17

75% of the extracellular matrix is water. the other 25% is organic matter containing _____ and _____.

Answer 17

Collagen type II and proteoglycan aggregates.

Question 18

What is the difference between collagen type I and type II?

Answer 18

Collagen II is finer and forms a 3D meshwork while collagen I is thicker and forms a 2D linear structure.

Question 19

Name the three types of cartilage

Which is most common?

Answer 19

Hyaline - most common
Elastic
Fibrocartilage

Question 20

Describe hyaline cartilage

Answer 20

Glassy - blue/white colour - most common form

Question 21

Describe elastic cartilage

Answer 21

Light yellow - flexible due to elastin fibres

Question 22

Describe fibrocartilage

Answer 22

Hybrid between tendon and hyaline cartilage. White - contains lots of type I collagen.

Question 23

Bone is composed of live cells and therefore is vascular true/false

Answer 23

True

Question 24

What percentage of all the calcium stored in the body is stored by/in bone?

Answer 24

95%

Question 25

The bone forms blood cells also - this process is called what?

Answer 25

Haematopoesis

Question 26

Where is blood initially formed in utero before being moved to the marrow?

Answer 26

liver and spleen

Question 27

Where are almost all blood cells formed by the early/mid twenties in life? What is formed in most bone marrow after this age?

Answer 27

The axial and limb girdle skeleton.

Fat - yellow marrow

Question 28

What is the dense layer of bone called?

Answer 28

Cortical bone

Question 29

What is the softer part of bone called?

Answer 29

Trabecular/cancellous bone