Histology

Question 1

What muscle fibres are generally referred to as ‘red’ fibres?

What muscle fibres are generally referred to as ‘white’ fibres?

Answer 1

Type I (slow twitch) - red

Type IIx (fast twitch) - white

Think of if someone runs super fast they are like a flash of white

Question 2

What is the cell membrane called in muscle cells?

What are located just underneath the cell membrane in muscle cells?

Answer 2

Sacrolemma

Multiple nuclei

Question 3

What is the name given for a group of muscle fibres?

Answer 3

Fascicle

Question 4

What is the name for the connective tissue surrounding:

• The whole muscle
• A single fascicle
• A single muscle fibre

Answer 4

Whole muscle = epimysium
Single fascicle = perimysium
Single muscle fibre = endomysium

Question 5

What are the 3 types of cartilage?
How do they appear grossly?
What is the most common?

Answer 5

Hyaline - blue/white - most common
Elastic - yellow
Fibrocartilage - white

Question 6

What are proteoglycans made up of?

What is the purpose of proteoglycans in the ECM of cartilage?

Answer 6

GAGs
Glycosaminoglycans

To resist compression

Question 7

What cells help maintain cartilage?
What are they known as before they mature?
Where do they exist with the ECM?

Answer 7

Chondrocytes
Chondroblasts
Lacuna - (think of as a little spongy prison within the ECM)

Question 8

What marrow is involved in haemopiesis?

What part of skeleton is this found in once you’re in your early 20s?

Answer 8

Red marrow

Axial skelton and limb girdle

Question 9

What makes up the majority of bone?

Answer 9

Bioapatite (mostly a form of calcium phosphate)

Question 10

What part of the bone is the epiphysis, metaphysis and diaphysis?

Answer 10

Look at diagram in Onenote

Question 11

What is the most notable difference between cancellous and cortical bone?

Where do you find each type?

Answer 11

Cancellous have no Haversian canals
Cancellous is also more porous - a fine meshwork which looks more like an Aero bar

Cancellous - head of bone

Cortical - shaft

Question 12

Cortical bone can be described as lamellar bone, why?

Answer 12

Arranged into layers

Question 13

Describe the structure of an osteon

Answer 13

Osteon are made up of layers of lamellae with a Haversian canal in the centre

These run laterally

Question 14

What is the name for the canal in bone which runs transversally?

Answer 14

Volkmann’s canal

think Walkmann’s - walking along horizontal

Question 15

Where are osteocytes found?

Answer 15

In lacunae (more concrete than in cartilage)

Question 16

For each of the following cells found in bone describe their function:
Osteocytes
Osteoblasts
Osteoclasts
Osteoprogenitor

What is the largest of these cells?

Answer 16

Osteocytes - bone cells found stuck within bone matrix
Osteoblasts - bone forming cells
Osteoclasts - break down and destroy bone
Osteoprogenitor - forms a pool of reserve osteoblasts

Osteoclasts - largest, multinucleated

Question 17

What is the name given to the first bone which is laid down after a break?

Answer 17

Woven bone - collagen runs in random directions

This Type I collagen will then be replaced and laid neatly following bone remodelling

Question 18

No cell secretes bone so how is bone formed?

Answer 18

Osteoblasts secrete osteoid

This mineralizes over time in extracellular space

Question 19

Describe the process of bone remodelling

Answer 19

Osteoclasts break down bone

Osteoblasts lay new layers of bone until all that is left is an osteon with a Haversian canal in the centre

Question 20

What is the name given to the defined line seen around an osteon?

Answer 20

Cement line