Histology

Question 1

Describe skeletal muscle cells

Answer 1

Unbranced, multinucleate, nuclei are at periphery of fibre-just under sarcolemma

Question 2

What is the name of the cell membrane in muscle cells?

Answer 2

Sarcolemma

Question 3

What are the bundles that muscle fibres are grouped into called?

Answer 3

Fascicles

Question 4

What is the connective tissue surrounding the muscle as a whole?

Answer 4

Epimysium

Question 5

What is the connective tissue around a single fascicle?

Answer 5

Perimysium

Question 6

What is the connective tissue around a single muscle fibre?

Answer 6

Endomysium

Question 7

What happens to the axon of motor neurone as it nears termination?

Answer 7

It branches

Question 8

Where does each branch of the axon of motor neurone end?

Answer 8

In a special type of synapse called the neuromuscular junction

Question 9

What are the 3 types of skeletal muscle fibre?

Answer 9

Type I, IIA, IIB

Question 10

Describe type I skeletal muscle fibres

Answer 10

Relatively slowly contracting fibres that depend on oxidative metabolism. They have abundant mitochondria, are resistant to fatigue and produce relatively less force. Often called ‘red’ fibres.

Question 11

Describe type IIA skeletal muscle fibres

Answer 11

This is intermediate between the other two. They are relatively fast contracting, but are also reasonably resistant to fatigue. These fibres are relatively uncommon

Question 12

Describe type IIB skeletal muscle fibres

Answer 12

Fast contracting fibres that depend on anaerobic metabolism. They have few mitochondria, fatigue relatively easily and produce relatively greater force. Often called ‘white’ fibres.

Question 13

How are cartilage cells nourished?

Answer 13

Diffusion through the extracellular matrix

Question 14

What are the cells found in cartilage?

Answer 14

Chondrocytes (chondroblasts when immature)

Question 15

Where are chondrocytes found?

Answer 15

Lacuna- a space in the extracellular matrix

Question 16

What is the relation between chondrocytes and the extracellular matrix?

Answer 16

They secrete and maintain it around them

Question 17

What is the most common form of cartilage?

Answer 17

Hyaline

Question 18

What is the make up of ECM in hyaline cartilage?

Answer 18

75% water, 25% organic material (of which 60% is type II collagen, 40% proteoglycan aggregates)

Question 19

What are the 3 types of cartilage?

Answer 19

Hyaline, elastic, fibrocartilage

Question 20

Describe the gross appearance of hyaline cartilage

Answer 20

Blue-white in colour and translucent

Question 21

Describe the gross appearance and flexibility of elastic cartilage

Answer 21

Light yellow in colour, addition of elastic fibres makes it quite flexible

Question 22

Describe the structure and gross appearance of fibrocartilage

Answer 22

Hybrid between tendon and hyaline cartilage. It has bands of densely packed type I collagen interleaved with rows of chondrocytes surrounded by small amounts of cartilagenous ECM. Appears white.

Question 23

Where may you find hyaline cartilage?

Answer 23

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

Question 24

By the early twenties what parts of the skeleton are involved in blood production?

Answer 24

Axial and limb girdle

Question 25

What is the composition of bone?

Answer 25

65% mineral, 23% collagen, 10% water, 2% non-collagen proteins

Question 26

What is the outer shell of dense cortical bone that makes of the shaft?

Answer 26

Diaphysis

Question 27

What bone occupies the ends of the bone ( the epiphyses)?

Answer 27

Cancellous or trabecular

Question 28

What is the main difference between compact and trabecular bone?

Answer 28

Presence of spaces (marrow cavities) adjacent to trabecular bone

Question 29

What are the lines that are often visible surrounding the osteon?

Answer 29

Cement lines

Question 30

What are osteoprogenitor cells?

Answer 30

Located on bone surfaces, for example under the periosteum, these cells serve as a pool of reserve osteoblasts

Question 31

What are osteoblasts?

Answer 31

Bone forming cells found on the surface of developing bone. They have plentiful RER and prominent mitochondria.

Question 32

What are osteocytes?

Answer 32

Bone cell trapped within the bone matrix

Question 33

What are osteoclasts?

Answer 33

Large (up to 40 microns or more) multinucleated cells. Found on surface of bone and are responsible for bone resorption

Question 34

What is the name for the collection of osteoclasts/blasts that participate in the cutting cone process in a tunnel is drilled into the bone, in which a blood vessel grows into and the tunnel is lined with osteoblasts which lay down new lamellar bone?

Answer 34

Basic multicellular unit (BMU)

Question 35

Until when does the cutting cone process involving the BMU continue?

Answer 35

Until only the space of a Haversian canal remains

Question 36

What is the mineral that principally makes up bone?

Answer 36

Calcium phosphate crystals, particularly hydroxyapatite: (Ca10(PO 4)6(OH)2

Question 37

What is collectively termed osteoid?

Answer 37

The osteoblast secretion of collagen, glycosaminoglycans (GAGs), proteoglycans and other organic components of the matrix

Question 38

What bone is formed during development or following a break?

Answer 38

Woven bone