BL L24 (rev)

Question 1

Read about the histology - in the PP

Question 2

Name the types of connective tissue

Answer 2

Question 3

Location of the different types of connective tissue

Answer 3

Question 4

Embryology summary

Answer 4

Question 5

Gastrulation summary

Answer 5

Question 6

Embryology - folding

Answer 6

• Somites – you need to know this information
• Dermatomes and myotomes – you need to know this information
• What structure ends up as the spinal cord?
• How the trilaminar disk folds and what it achieves

Question 7

Bone - things to think about

Answer 7

• 5 Types – What are they called? Can you give an example?
• Which method: endochondral or intra-membranous ossification is used to make them? Can you distinguish between these two methods of bone formation?
• What are the differences between cortical and cancellous bone?
• When are bones made?
• What cells are involved, what are they called and where do they come from?
• What happens when a mature bone repairs itself? What are the different stages of bone repair called and can you describe what happens at each stage? • How long does bone remodelling take for a child, an adolescent, an adult or an elderly person?

Question 8

Endochondral ossification

Answer 8

Question 9

Cancellous bone

Answer 9

Question 10

Compact (cortical) bone

Answer 10

The functional unit:
• Osteon
• Layers (lamellae) of compact mineralised collagen • Trap osteoblasts that produced the bone – osteocytes are terminally differentiated
• They sit in small depressions (lacunae)
• Send out long filipodia to ‘communicate’ with other osteocytes
• Osteoblasts are intermediate cells - these make osteopontin and osteocalcin and lay down new bone at the edges
• NB Osteoclasts are not found in cortical bone
• only on the edges (periosteum and endosteum) where they degrade bone

Question 11

Cells in bones

Answer 11

Osteoprogenitor:
Undifferentiated cells - stem cell Inner layer of endosteum and periosteum

Osteoblast:
Intermediate cells that cannot divided Inner layer of endosteum and spicules Lay down new bone

Osteocyte:
Terminally differentiated bone cell Trapped within osteon No longer lay down matrix – tissue maintenance

Osteoclast:
Huge cells (as many as 50 nuclei) Fused monocytes (WBCs) On the surface of cortical bone (endosteum) Resorption of existing bone

Question 12

Fracture repair overview

Answer 12

Question 13

1. Hematoma forms

Answer 13

Question 14

2. Procallus formation

Answer 14

Question 15

3. Fibrocartilage form

Answer 15

Question 16

4. Bony callus

Answer 16

Question 17

5. Bone remodelling

Answer 17

Question 18

Time it takes to remodel upper limbs

Answer 18

Question 19

Contrast media

Answer 19

​• Why is it used?
• What substances can be used?
• What side effects are apparent from the use of such substances?
• Orientation of images (important!)
• Naming of different parts of the body using ‘anatomical terminology’ (as per Dr Jennison’s and Dr Jacques’ lectures)

Question 20

Alveolus - structure

Answer 20

• In the alveoli , the capillaries are lined with flattened specialised epithelial cells (endothelium) that are attached to a fused basal lamina with even thinner epithelial cells of the air sac on the opposite side
• The folds in the basal lamina allow for expansion of the air sacs when air is drawn into the lungs
• At the junction are small amounts of collagen that add rigidity to the mucosa surrounded by many layers of elastin fibres, whose role is to provide elastic recoil to return the sac to the empty state on exhaling gases
• The connective tissue muscle layers in this mucosa are created by the collagen and elastin fibres

Question 21

Two types of pneumocytes

Answer 21

•Type 1 pneumocyte: The cell responsible for the gas (oxygen and carbon dioxide) exchange that takes place in the alveoli. It is a very large thin cell stretched over a very large area. This type of cell is susceptible to a large number of toxic insults and cannot replicate itself. •Type 2 pneumocyte: The cell responsible for the production and secretion of surfactant (the molecule that reduces the surface tension of pulmonary fluids and contributes to the elastic properties of the lungs). The type 2 pneumocyte is a smaller cell that can replicate in the alveoli and will replicate to replace damaged type 1 pneumocytes.