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Year 2 - Musculoskeletal (DP) > Histology > Flashcards

Flashcards in Histology Deck (57):
1

What are the three main features of skeletal muscle?

Striated
Unbranched
Multinucleate

2

What is a syncytium? Give an example?

A multinucleate cell that forms from fusion of many uninucleate cells
Skeletal muscle cell

3

How long and wide are skeletal muscle cells/fibres?

10-100 micrometre diameter
1,000-200,000 micrometre long

4

Where are the nuclei located in skeletal muscle cells?

At the peripheries

5

What is the sarcolemma?

Muscle cell membrane

6

What are muscle fibres grouped into?

Fascicles

7

What is the name for the connective tissue surrounding the following:
1. Single muscle fibre
2. Single fascicle
3. Whole muscle

1. Endomysium
2. Perimysium
3. Epimysium

8

What is a myofibril?

Sarcomeres end to end

9

How can you tell that the myofibrils are held in registry with one another?

Z-discs all aligned

10

What does a motor unit consist of?

One motor neurone
All muscle fibres it innervates

11

True or false; More muscles fibres in a motor unit = More precise movement control?

False
The fewer muscle fibres a motor neurone supplies in a unit, the more precise a movement will be

12

True or false; The muscle fibres supplied by a motor neurone are scattered throughout the muscle?

True (They are all the same fibre type but do not have to be bundled together)

13

How do the three types of skeletal muscle fibres appear on succinate dehydrogenase stain?

Type i - Blue
Type iia - Pale blue
Type iib - White

14

Rank the types of skeletal muscle fibres in terms of contractile speed

Type iib
Type iia
Type i

15

Rank the types of skeletal muscle fibres in terms of resistance to fatigue and explain why

Type i
Type iia
Type iib

16

What type of muscle fibre is dependent on oxidative metabolism?

Type i

17

What type of muscle fibre is dependent on anaerobic metabolism?

Type iib

18

What type of muscle fibre is most uncommon?

Type iia

19

What type of muscle fibres are the following terms describing;
1. Red
2. White
3. Produce least force
4. Produce most force
5. Intermediate

1. Type i
2. Type iib
3. Type i
4. Type iib
5. Type iia

20

What is this describing?
A semi-rigid substance that is very permeable. It is avascular and its cells are nourished vis diffusion through the ECM

Cartilage

21

What is this describing?
A rigid substance that is non-permeable. It receives nourishment from blood vessels

Bone

22

Where are chondrocytes found? Specifically?

Cartilage
In ECM - LAcuna

23

What is the name for immature chondrocytes?

Chondroblasts

24

What is the function of chondrocytes?

Secrete and maintain ECM

25

What is the most abundant component of hyaline cartilage?

ECM

26

What is the most abundant component of the ECM in cartilage? What % does it make up?

Water
75%

27

What makes up the rest of the ECM in cartilage? What % does it make up?

25% total
60% of which is Type ii Collagen:
- Forms 3D mesh
40% of which is proteoglycan aggregates:
- Made of GAGs
- Bound to core protein
- Often linked to hyaluronon

28

How does Type ii Collagen differ from Type i?

Finer (15-45nm vs 75nm)
Type i found in connective tissue

29

What are the three types of cartilage?

Hyaline
Elastic
Fibrocartilage

30

How do each type of cartilage appear?

Hyaline - Blue/White + Translucent
Elastic - Yellow
Fibrocartilage - White

31

What is the most common form of cartilage?

Hyaline

32

What is fibrocartilage?

Tendon-Hyaline hybrid
Bands of dense type i Collagen:
- Interweaved with chondocytes
- Surrounded by little ECM

33

Which of the following is not a place where hyaline cartilage is found:
- Articular surfaces
- Tracheal rings
- Costal cartilage
- Pinnae
- Epiphyseal growth plate

Pinnae (Outer ear - Elastic cartilage)

34

Where does haemopoiesis occur in utero?

Liver and spleen
(Begins in bone marrow)

35

What are the components of bone?

Mineral - Calcium hydroxyapatite (65%)
Collagen - Type i (23%)
Water (10%)
Non-collagen proteins (2%)

36

What type of bone makes up the outer shell and the diaphysis?

Cortical

37

What type of bone is present at the epiphyses?

Cancellous/Trabecular

38

What is the difference between the two bone types?

Cortical is dense; Cancellous is a fine mess
- Marrow cavities are next to cancellous bone

39

What do Haversian canals convey?

Blood vessels and nerves

40

What structures link Haversian canals to each other and the periosteum?

Volkmann's canals

41

What is the functional unit of bone called? What is it surrounded by?

Osteon
Cement line

42

What bone cells are located on the surface and are pools of reserve osteoblasts?

Osteoprogenitor cells

43

What is the function of osteoblasts?

Form bone

44

Where are osteoblasts located and what cellular features do they possess?

On surface of developing bone
Features:
- Plentiful RER
- Prominent mitochondria

45

Where are osteocytes found?

Trapped in bone matrix

46

What do osteoclasts look like?

Large (40 micrometres)
Multinucleated

47

What is the function of osteoclasts and where are they found?

Bone reabsorption
On bone surface

48

What makes up the Basic Multicellular Unit?

Osteoclasts + Osteoblasts

49

How does bone remodelling occur?

1. Osteoclasts congregate
2. Osteoclasts 'drill' into bone
3. Blood vessels grow into tunnel - Bring osteoblasts
4. Osteoblasts line tunnel -> Lay down new bone
5. Continues until tunnel is filled in right up to vessels -> Haversian canal

50

Where do osteoclasts derive from?

Macrophage lineage
Several fuse into giant cell

51

What is the chemical formula of calcium hydroxyapatite?

Ca10(PO4)6(OH)2

52

What do osteoblasts secrete and what is it made up of?

Osteoid:
- Collagen
- Glycosaminoglycans (GAGs)
- Proteoglycans
- Other

53

How is the bone ECM formed?

Osteoid mineralises over time

54

What effect can younger osteons have on older osteons?

Can partially obliterate them

55

What is woven bone?

New bone laid done haphazardly:
- During development
- After fracture

56

What is woven bone remodelled into and how?

Lamellar bone:
- Osteoclasts break it down
- Osteoblasts reform it

57

What direction do the fibres in lamellar bone travel in?

All the same direction