Histology Flashcards

1
Q

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

A

cell becomes packed with filaments which push nuclei to the edge

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2
Q

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

A

endomysium

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3
Q

What is the connective tissue around a single fascicle called?

A

perimysium

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4
Q

What is the connective tissue around a whole muscle caleld?

A

epimysium

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5
Q

How are sarcomeres arranged into myofibrils?

A

arranged end-to-end

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6
Q

How are myofibrils arranged in the fibre?

A

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

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7
Q

Why do SK muscle fibres appear striated?

A

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

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8
Q

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

A

scattered across the muscle and are not bunched together

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9
Q

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

A

type 1- they have lots of myoglobin to store oxygen

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10
Q

How are cartilage cells nourished?

A

diffusion through extracellular matrix as cartilage is avascular

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11
Q

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

A

bone is not permeable

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12
Q

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

A

lacuna

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13
Q

What is connective tissue?

A

has lots of volume occupied by ECM rather than by cells

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14
Q

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

A

3/4- water

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

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15
Q

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

A

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

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16
Q

What are proteogylcans made up of?

A

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

17
Q

What does hyaline cartilage look like?

A

blue-white in colour and translucent

18
Q

What does elastic cartilage appear as?

A

light yellow

19
Q

What is fibrocartilage made up of?

A

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

20
Q

What are the 2 types of bone?

A

outer shell of dense cortical bone and cancellous/trabecular bone

21
Q

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

A

shaft-diaphysis

22
Q

What area of long bone does cancellous bone occupy?

A

ends of bone- epiphyses

23
Q

What is the main difference between compact and trabecular bone?

A

presence of spaces (marrow cavities) in trabecular bone

24
Q

What is an osteon?

A

the functional unit of compact bone

25
Q

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

A

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

26
Q

what are the canaliculi in bone?

A

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

27
Q

What is the purpose of canaliculi?

A

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

28
Q

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

A

lines that surround the osteon- cement lines

29
Q

What does trabecular bone lack in comparison to compact bone?

A

lacks Haversion canals (up and down)

30
Q

Why doesnt trabecular bone need Haversion canals?

A

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

31
Q

Where are osteoprogenitor cells found?

A

bone surfaces, eg under the periosteum

32
Q

What is the function of osteoprogenitor cells?

A

cells serve as a pool of reserve osteoblast

33
Q

What are osteoblasts for?

A

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

34
Q

What osteocytes?

A

a bone cell trapped within the bone matrix

35
Q

What are osteoclasts

A

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
Q

What happens during bone remodelling?

A

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
Q

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

A

basic multicellular unit

38
Q

What is the difference between lamellar and woven bone?

A

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