Histology Flashcards

1
Q

what three key words describe skeletal muscle cells

A

striated, unbranched, multinucleated

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2
Q

where are the nuclei in muscle cells found

A

at the periphery of the fibre, just under cell membrane (sarcolemma)

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3
Q

how long are muscle cells

A

as long as the muscle

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4
Q

what are muscle cells grouped into

A

fascicles

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5
Q

what is the epimysium

A

the connective tissue that surrounds the whole muscle

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6
Q

what is the perimysium

A

the connective tissue around a single fascicle

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7
Q

what is the endomysium

A

the connective tissue around a single muscle fibre

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8
Q

what are sarcomeres

A

the functional unit- unit of contraction of the muscle cell (smallest contractile element)

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9
Q

list what makes up a muscle cell

A

muscle fibre= lots of myofibrils= lots of sacromeres

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10
Q

what makes up band A

A

myosin (dark, thick)

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11
Q

what makes up the I band

A

actin (light)

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12
Q

what creates the striations in muscle cells

A

regular patterns of alternating dark and light bands (z discs aligned)

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13
Q

what is the motor unit

A

one motor neurone and all of the muscle fibres that it innervates

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14
Q

what happens to the axon of the muscle fibre as it nears its termination

A

branches to synapse with more neuromuscular junctions

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15
Q

describe type I muscle fibres

A

relatively slow contracting, depend on oxidatitive metabolism, have abundant metabolism and are resistant to fatigue. produce relatively less force- red fibres

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16
Q

describe type IIa muscle fibres

A

relatively fast contracting, reasonably resistant to fatigue, relatively uncommon

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17
Q

describe type IIB fibres

A

fast contracting, depend on anaerobic metabolism, few mitochondrian, less myoglobin, fatigue easily, produce greater force- white fibres

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18
Q

does cartilage have a blood supply

A

no is avascular- blood diffuses into it through matrix

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19
Q

is bone permeable

A

no

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20
Q

what are chondrocytes

A

the cell found in cartilage

21
Q

what are chondroblasts

A

immature cartilage cells

22
Q

what is a lacuna

A

space in the extracellular matrix in which chondrocytes live

23
Q

what do chondrocytes do

A

seceret and maintain the extracellular matrix around them

24
Q

what organic material makes up hyaline (extra cellular matrix) cartilage

A

type II collagen and proteoglycan aggregates

25
what is the most common type of cartilage
hyaline
26
describe hyaline cartilage
blue/white in colour and translucent
27
describe elastic cartilage
light yellow, elastic fibres make it quite flexible
28
describe fibrocartilage
hybrid between tendon and hyaline cartilage has bands of densely packed type one collagen interleaved with rows of chondrocytes surrounded by small amounts of cartilagenous ECM appears white
29
where is hyaline cartilage found
articular surfaces tracheal rings costal cartilage epiphyseal growth plates precursor in fetus to many bones
30
what are the functions of bone (5)
``` support levels protection of internal organs calcium store haemopoiesis (blood cell production) ```
31
what makes up bone
23% collagen 65% bioapatitie (form of calcium phosphate, mostly hydroxyaptite) 10% water 2% non collagen proteins
32
what type of bone makes up the diaphysis (shaft)
cortical bone
33
what type of bone makes up the epiphyses (ends of the bone)
cancellous or trabecular bone
34
does bone remodel
yes constantly throughout life
35
what is a haversian canal
blood vessel inside each lamellae circle (osteon)
36
what is the main different between compact and trabecular bone
presence of spaces (marrow cavities) adjacent to trabecular bone
37
what are osteocytes
bone forming cells found on the surface of developing bone
38
what are cement lines
line visible around osteons, formed during remodelling
39
describe the morphology of trabecular bone
has osteocytes and is lamellar in nature but generally lacks haversian canals
40
what are osteoprogenitor cells
cells located on bone surfaces (e.g. under periosteum) that serve as pool of reserve osteoblasts
41
what is an osteocyte
a bone cell trapped within the bone matrix
42
what is an osteoclast
large multinucleated cells found on the surface of bone and are responsible for bone resorption
43
describe the 'cutting cone' of bone remodelling
when a number of osteoclasts congregate and 'drill' into bone forming a tunnel. a blood vessel will grow into the tunnel bringing with it osteoblasts which line the tunnel and begin laying down new lamellar bone. this continues until only space of a haversian canal remains
44
what us a basic multicellular unit
collection of osteoclast and osteoblasts involved in bone remodelling
45
what do osteoblasts do
secret collagen, glycosaminoglycans (GAGs), proteoglycans and other organic components of matrix= osteoid which becomes mineralised over time
46
what are osteoclasts derived from
macrophage lineage
47
what do osteoclasts form if they fuse
giant cells
48
where matrix secrete that will become be added on to
only to surface of existing bone
49
what is woven bone
disorganised bone that is layed down in response to a fracture