MSK Histology

Question 1

how can skeletal muscles be described

Answer 1

striated
unbranched
multinucleate

Question 2

what do muscle fibres look like

Answer 2

long cylanders

nuclei are at the periphery of the fibre just under the cell membrane

Question 3

what is the cell membrane called in muscle cells

Answer 3

sarcolemma

Question 4

what is skeletal muscle made up of

Answer 4

fascicles - individuals bundles of muscle fibres

Question 5

what is the name of the connective tissue that surrounds to whole muscle

Answer 5

epimysium

Question 6

what is the connective tissue around a single fascicle called

Answer 6

perimysium

Question 7

what is the connective tissue around a single muscle fibre called

Answer 7

endomysium

Question 8

what is inside a muscle fascicle

Answer 8

muscle fibres

Question 9

whats inside a muscle fibre

Answer 9

myofibrils

Question 10

what are myofibrils made up of

Answer 10

sarcomeres placed end to end

Question 11

by definition where does the sarcomere stretch between

Answer 11

Z lines

Question 12

what causes striation in skeletal muscle

Answer 12

result of the arrangement of the sarcomeres held in registry with one another across the fibre giving the illusion of transversal stripes

Question 13

what is the neuromuscular junction

Answer 13

the synapse where the axon on the motor neurone terminates

Question 14

describe type 1 muscle fibres

Answer 14

slow contracting 
depend on oxidative metabolism 
abundant mitochondria and myoglobin 
resistant to fatigue and produce less force 
'red fibres'

Question 15

describe type 2a muscle fibres

Answer 15

intermediate between 1 and 2b
relatively fast contracting
reasonably resistant to disease
relatively uncommon

Question 16

describe type 2b muscle fibres

Answer 16

fast contracting fibres that depend on anaerobic metabolism
very few mitochondria and less myoglobin than type 1 fibres
fatigue relatively easily
produce greater force
‘white meat’

Question 17

describe cartilage

Answer 17

semi-rigid and deformable
permeable
avascular
cells nourished by diffusion through ECM

Question 18

describe bone

Answer 18

rigid
non-permeable
cells nourished by blood vessels that pervade the tissue

Question 19

what are chondrocytes

Answer 19

cells found in cartilage

called chondroblasts when immature

Question 20

what are the components of the ECM

Answer 20

75% water
25% organic material
type 2 collagen
proteoglycan aggregates

Question 21

what is hyaline cartilage

Answer 21

most common form of cartilage

blue-white in colour

Question 22

what is elastic cartilage

Answer 22

light yellow in colour

addition of elastic fibres make it flexible

Question 23

what is fibrocartilage

Answer 23

hybrid between tendon and hyaline cartilage
bands of densely packed type 1 collagen interwoven with rows of chondrocytes
surrounded by ECM
appears white

Question 24

where is hyaline cartilage found

Answer 24

articular surfaces 
tracheal rings 
costal cartilage 
epiphyseal growth plates 
precursor in fetus to many bones

Question 25

what are the functions of bone

Answer 25

``` support levers for moment protection of internal organs calcium store haemopoiesis (blood cell production) ```

Question 26

what is cauliflower ear

Answer 26

when vasculature around the cartilage is damaged so it cant get nourished from diffusion

Question 27

where is involved in blood production after early 20s

Answer 27

axial skeleton and limb girdle

Question 28

what is marrow not producing blood

Answer 28

yellow marrow | producing fat

Question 29

what makes up bone

Answer 29

collagen bioapatitie (a form of calcium phosphatte- mineral) water non-collagen proteins

Question 30

what is cortical bone

Answer 30

the outer shell of dense bone which makes up the shaft

Question 31

what is cancellous/trabecular bone

Answer 31

occupies the ends of bone | fine meshwork of bone which looks like an aero bar

Question 32

what bone never remodels

Answer 32

otic capsule

Question 33

what makes up cortical bone

Answer 33

groups of lamellar bone blood vessels within canal in the middle canals run both ways through the bone

Question 34

what are osteons

Answer 34

groups of lamellar bodies | product of later bone remodelling

Question 35

why do osteons have a lamellar structure

Answer 35

lots of different layers overlapping with collagen fibres in different directions to make it stronger

Question 36

what is a key difference between trabecular and compact bone

Answer 36

presence of spaces in trabecular bone

Question 37

what are canaliculi

Answer 37

tiny channels which allow communication between osteocytes

Question 38

what is the cement line

Answer 38

marks the boundary of an osteon | only found in osteons that are formed from remodelling

Question 39

why does trabecular bone lack Haversian canals

Answer 39

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

Question 40

what are osteoprogenitor cells

Answer 40

located on bone surfaces | pool of reserve osteoblasts

Question 41

what are osteoblasts

Answer 41

bone forming cells found on the surface of developing bone

Question 42

what are osteocytes

Answer 42

bone cell trapped within bone matrix

Question 43

what are osteoclasts

Answer 43

``` large multibucleated cells found on the surface of the bone responsible for bone reabsorption work together to dissolve the bone fuse to form giant cell ```

Question 44

what happens to bone during remodelling

Answer 44

osteoclasts drill out bone to form a tunnel blood vessels grow into tunnel bringing osteoblasts osteoblasts start laying down new lamellar bone process continues until only the Haversian canal remains

Question 45

what do osteoblasts secrete

Answer 45

osteoid | a progenitor material which in the extracellular space will become hard as it attracts calcium phosphate crystals

Question 46

what are osteoclasts derived from

Answer 46

macrophages

Question 47

where can you add bone to

Answer 47

a surface

Question 48

how is early bone lade down in utero

Answer 48

quickly as woven bone collagen fibres run in all orientations

Question 49

when is woven bone put down

Answer 49

when there is a break | then undergoes subsequent remodelling