!!!Week 3: Histology of Cartilage, bone and skeletal muscle

Question 1

Matrix of cartilage?

Answer 1

Fibres and ground substance (water holding molecules)

Question 2

Matrix of bone?

Answer 2

fibres and ground substance (Hyroxyapatite)

Question 3

Where are cartilage and bone arise from?

Answer 3

mesenchyme - lateral somatopleuric mesoderm of embryo

Question 4

CLASSIFICATIONS of cartilage?

Answer 4

Hyaline, elastic, fibrocartilage

Question 5

Hyaline cartilage features?

Answer 5

Type II collagen fibres, proteoglycans (GAGs) etc

Question 6

Elastic cartilage features?

Answer 6

Elastic fibres, elastic lamellae, collagen, proteoglycans (GAGs) etc - DOES NOT CALCIFY W AGE

Question 7

Fibrocartilage features?

Answer 7

Type I collagen fibres, fibroblasts, proteoglycans (GAGs) etc - NO PERICHONDRIUM

Question 8

What type of cartilage is s precursor to most bone?

Answer 8

Hyaline

Question 9

Where is hyaline cartilage found?

Answer 9

Respiratory tract, articular surfaces synovial joints

Question 10

Features of active chondroblasts and chondrocytes?

Answer 10

Abundant rough ER, prominent golgi - pale area next to nucleus in light microscope

Question 11

What does the perichondrium consist of?

Answer 11

Outer fibrous layer, inner cellular layer - resemble fibroblasts (chondroprogenitor), give rise to chondroblasts

Question 12

What are the precursor cells to chondrocytes?

Answer 12

Chondroblasts or other chondrocytes

Question 13

Adult, mature bone is called what? What are the types?

Answer 13

Lamella bone - compact (dense) or spongy (trabecula).

Question 14

Types of compact bone?

Answer 14

Circumferential (inner, outer), Haversion (osteon) and interstitial

Question 15

Outer component of bone? Parts?

Answer 15

Periostum - outer fibrous (fibroblasts, collagen etc), inner cellular -

Question 16

Where are osteoprogenitor cells located?

Answer 16

Inner cell layer of periosteum, endosteum

Question 17

What canal joints osteons?

Answer 17

Volkmans canals

Question 18

T or F: The endosteum only has a single layer of cells and no outer fibrous layer

Answer 18

T

Question 19

Osteoprogenitor cells. Location, shape

Answer 19

Bone surfaces, squamous

Question 20

Osteoblasts. shape

Answer 20

differentiated bone forming cells - secretes collagen and matrix cells, calcifies bone matrix. cuboidal

Question 21

Osteoclasts from which cell line

Answer 21

hemopoitic progenitor cell

Question 22

Osteoclasts shape

Answer 22

large, dome shaped, multinucleated, ruffled border

Question 23

What sits in Howship’s lacuna?

Answer 23

osteoclasts

Question 24

What is unmineralised bone called?

Answer 24

Osteoid

Question 25

Muscle acting concentrically

Answer 25

Shortening

Question 26

Muscle acting isometrically

Answer 26

Generating force but not shortening

Question 27

Muscle acting eccentrically

Answer 27

Generating force while lengthening

Question 28

What CT are tendons made from?

Answer 28

Dense regular CT

Question 29

What are the contractile cells in skeletal msucle called?

Answer 29

Extrafusal

Question 30

What are red fibres?

Answer 30

Slow acting, aerobic

Question 31

What are white fibres?

Answer 31

Faster acting, anaerobic

Question 32

How does skeletal muscle form?

Answer 32

Fusion of myoblasts

Question 33

Once formed, cam skeletal muslce divide?

Answer 33

NO

Question 34

In ythe light microscope, what are the dark bands?

Answer 34

A bands

Question 35

What is the A band composed of?

Answer 35

Thick (myosin) and thin (actin) filaments

Question 36

What is the I band composed of?

Answer 36

THin filaments only

Question 37

What is the H band composed of?

Answer 37

Thick filaments only

Question 38

What does troomyosin do?

Answer 38

Attaches on actin - blocks actin binding sites

Question 39

What does troponin do?

Answer 39

Binds calcium, actin and tropomyosin

Question 40

What binds thick filaments to the Z line

Answer 40

Titin

Question 41

T or F: The thick filaments are not bound to the Z line

Answer 41

False - connected via titin

Question 42

What motor fibres activate contraction?

Answer 42

Alpha motor fibres, lower motor neurons

Question 43

How many NMJ are there usually per cell?

Answer 43

1

Question 44

What motor neurons innervate intrafusal fibres>?

Answer 44

Gamma

Question 45

What is the transmitter at the NMJ?

Answer 45

Acetylcholine

Question 46

What activates the actin-myosin interaction?

Answer 46

Calcium

Question 47

How is the activation of skeletal muscle reversed?

Answer 47

By calcium pumps - return calcium to SR

Question 48

Where are Triads located?

Answer 48

Adjacent to A band and I band

Question 49

Where do germinal cells reside in epiphyseal plate?

Answer 49

Reserve zone - near epiphysis