Histology

Question 1

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

Answer 1

cell becomes packed with filaments which push nuclei to the edge

Question 2

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

Answer 2

endomysium

Question 3

What is the connective tissue around a single fascicle called?

Answer 3

perimysium

Question 4

What is the connective tissue around a whole muscle caleld?

Answer 4

epimysium

Question 5

How are sarcomeres arranged into myofibrils?

Answer 5

arranged end-to-end

Question 6

How are myofibrils arranged in the fibre?

Answer 6

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

Question 7

Why do SK muscle fibres appear striated?

Answer 7

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

Question 8

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

Answer 8

scattered across the muscle and are not bunched together

Question 9

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

Answer 9

type 1- they have lots of myoglobin to store oxygen

Question 10

How are cartilage cells nourished?

Answer 10

diffusion through extracellular matrix as cartilage is avascular

Question 11

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

Answer 11

bone is not permeable

Question 12

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

Answer 12

lacuna

Question 13

What is connective tissue?

Answer 13

has lots of volume occupied by ECM rather than by cells

Question 14

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

Answer 14

3/4- water

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

Question 15

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

Answer 15

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

Question 16

What are proteogylcans made up of?

Answer 16

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

Question 17

What does hyaline cartilage look like?

Answer 17

blue-white in colour and translucent

Question 18

What does elastic cartilage appear as?

Answer 18

light yellow

Question 19

What is fibrocartilage made up of?

Answer 19

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

Question 20

What are the 2 types of bone?

Answer 20

outer shell of dense cortical bone and cancellous/trabecular bone

Question 21

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

Answer 21

shaft-diaphysis

Question 22

What area of long bone does cancellous bone occupy?

Answer 22

ends of bone- epiphyses

Question 23

What is the main difference between compact and trabecular bone?

Answer 23

presence of spaces (marrow cavities) in trabecular bone

Question 24

What is an osteon?

Answer 24

the functional unit of compact bone

Question 25

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

Answer 25

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

Question 26

what are the canaliculi in bone?

Answer 26

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

Question 27

What is the purpose of canaliculi?

Answer 27

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

Question 28

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

Answer 28

lines that surround the osteon- cement lines

Question 29

What does trabecular bone lack in comparison to compact bone?

Answer 29

lacks Haversion canals (up and down)

Question 30

Why doesnt trabecular bone need Haversion canals?

Answer 30

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

Question 31

Where are osteoprogenitor cells found?

Answer 31

bone surfaces, eg under the periosteum

Question 32

What is the function of osteoprogenitor cells?

Answer 32

cells serve as a pool of reserve osteoblast

Question 33

What are osteoblasts for?

Answer 33

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

Question 34

What osteocytes?

Answer 34

a bone cell trapped within the bone matrix

Question 35

What are osteoclasts

Answer 35

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

Question 36

What happens during bone remodelling?

Answer 36

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

Question 37

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

Answer 37

basic multicellular unit

Question 38

What is the difference between lamellar and woven bone?

Answer 38

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