Histology Flashcards Preview

MSK > Histology > Flashcards

Flashcards in Histology Deck (38):
1

Why are the nuclei SK cells found at the periphery of the fibre?

cell becomes packed with filaments which push nuclei to the edge

2

What is the connective tissue around a single muscle fibre called?

endomysium

3

What is the connective tissue around a single fascicle called?

perimysium

4

What is the connective tissue around a whole muscle caleld?

epimysium

5

How are sarcomeres arranged into myofibrils?

arranged end-to-end

6

How are myofibrils arranged in the fibre?

like cigarettes in a pack (not end-to-end)

7

Why do SK muscle fibres appear striated?

sarcomeres in the myofibrils with their alternating dark and light bands are held in registry (Z-lines line up)

8

How are the fibres in a motor unit arranged in the muscle?

scattered across the muscle and are not bunched together

9

What type of fibre are the red fibres in SK muscle?

type 1- they have lots of myoglobin to store oxygen

10

How are cartilage cells nourished?

diffusion through extracellular matrix as cartilage is avascular

11

Why must bone be nourished by blood vessels that pervade the tissue?

bone is not permeable

12

What is the space in the extracellular matrix that condrocytes live in called?

lacuna

13

What is connective tissue?

has lots of volume occupied by ECM rather than by cells

14

What is the ECM in hyaline (most common) cartilage?

3/4- water
1/4 organice material- type 2 collagen and proteoglycan aggregates

15

What is the diffference between type 1 and type 2 collagen?

type 2 is finer than type 1 and instead of aggregating into linear bundles, it forms a 3D meshwork

16

What are proteogylcans made up of?

GAGs (polysaccharides) bound to a core protein (testtube brush- GAG is brush and protein is metal handle throughit)

17

What does hyaline cartilage look like?

blue-white in colour and translucent

18

What does elastic cartilage appear as?

light yellow

19

What is fibrocartilage made up of?

bands of densely packed type 1 collagen interleaved with rows of chondrocytes surroudned by small amounts of ECM

20

What are the 2 types of bone?

outer shell of dense cortical bone and cancellous/trabecular bone

21

What area of the long bone does cortical bone make up?

shaft-diaphysis

22

What area of long bone does cancellous bone occupy?

ends of bone- epiphyses

23

What is the main difference between compact and trabecular bone?

presence of spaces (marrow cavities) in trabecular bone

24

What is an osteon?

the functional unit of compact bone

25

What is the difference between Haversion canals and Volkmann's canals?

Haversion bloos vessels go up and down the bone where as Volkmann's go across the bone

26

what are the canaliculi in bone?

holes that extend in all directions from osteocytes containing osteocyte cell processes

27

What is the purpose of canaliculi?

processes of cells join and cells closest to the bloos canal pass nutrients to further away cells

28

What are only found in osteons that have formed during remodeling (not in original development)?

lines that surround the osteon- cement lines

29

What does trabecular bone lack in comparison to compact bone?

lacks Haversion canals (up and down)

30

Why doesnt trabecular bone need Haversion canals?

because the struts are thin, the osteocytes can survive from contact with the marrow spaces

31

Where are osteoprogenitor cells found?

bone surfaces, eg under the periosteum

32

What is the function of osteoprogenitor cells?

cells serve as a pool of reserve osteoblast

33

What are osteoblasts for?

bone forming cells found on the surface of developing bone -secrete collagen, GAGs and other organic material (collectively called osteoid)-which forms bone

34

What osteocytes?

a bone cell trapped within the bone matrix

35

What are osteoclasts

large multinucleated cell (derived from macrophages which fused and formed a multinucleated cell) which are found on the surface of bone and do bone resorption

36

What happens during bone remodelling?

osteoclasts drill into bone forming a tunnel, a blood vessel grows into the tunnel bringing osteoblasts wwhich line the tunnel and lay down ner laemllar bone-keeps going until only the space of a Haversian canal reamins

37

What is the collection of osteoclasts and osteoblasts that participate in remodelling called?

basic multicellular unit

38

What is the difference between lamellar and woven bone?

collagen fibres are not all orientated in one direction but in a haphazard fashion-not as strong