Pathology of Muscles and Tendons

Question 1

What cells is muscle made up of?

Answer 1

mycocytes and satellite cells

Question 2

What are satellite cells important in?

Answer 2

healing muscle cells and adjacent bone fracture

Question 3

What type of cells are myocytes (I am not asking where they belong)?

Answer 3

multinucleated cells

Question 4

What does development of a myocyte require?

Answer 4

motor innervation

Question 5

What are the 3 types of myocytes based on innervation?

Answer 5

red (type 1), white (type 2A), intermediate (type 2b)

Question 6

Where are satellite cells located?

Answer 6

adjacent to myocytes inside the basal lamina

Question 7

What is the sarcolemma?

Answer 7

the myocyte plasma membrane

Question 8

What is the role of the T-tubules and where are they located?

Answer 8

they are an invagination of the sarcolemma and are specialized for depolarization

Question 9

What is the sarcoplasm?

Answer 9

the myocyte cytoplasm

Question 10

What are myofilaments?

Answer 10

filaments that attach to each other during muscle contraction

Question 11

What are the types of myofilaments?

Answer 11

myosin II filaments and actin filaments

Question 12

Myosin II filaments are known as ________ filaments.

Answer 12

thick

Question 13

Actin filaments are known as ______ filaments.

Answer 13

thin

Question 14

Where are myosin filaments anchored?

Answer 14

at the M line

Question 15

Where are actin filaments anchored?

Answer 15

at Z disk

Question 16

What makes actin filaments Ca regulated?

Answer 16

troponin and tropomysin

Question 17

What is a sarcomere?

Answer 17

the basic contractile unit of the monocyte

Question 18

What is the sarcomere composed of?

Answer 18

myofilaments

Question 19

What does the sarcomere extend from?

Answer 19

z disk to z disk

Question 20

What is a myofibril?

Answer 20

a linear string of sarcomeres that runs the length of the myocyte

Question 21

Explain the excitation -contraction coupling reaction.

Answer 21

1. nerve impulse 2. wave of depolarization on plasma membrane 3. T-tubule/SR release Ca into the sarcoplasm 4. Ca binds to Tr-Trpm-actin 5. confoormation change 6.actin ratchets up on myosin filaments 7. contraction (ATP dependant) 8. Ca pumbed back into SR (ATP) 9. Relaxation

Question 22

Describe skeletal muscle hypoplasia.

Answer 22

there are small poorly-differentiated myocytes due to loss of motor innervation during development

Question 23

Describe skeletal muscle hypertrophy.

Answer 23

increase in muscle mass due to increase in sarcomeres

Question 24

What usually is the cause for skeletal muscle hypertrophy?

Answer 24

increased work load

Question 25

Describe skeletal muscle atrophy.

Answer 25

decrease mass due to fewer and shorter myofilaments

Question 26

What is the cause of skeletal muscle atrophy?

Answer 26

decrease in work load or loss of motor innervation

Question 27

What exudate types are associated with inflammation of skeletal muscles?

Answer 27

serous, fubrinous, purulent, granulomatous

Question 28

What is inflammation in skeletal muscles frequently due to?

Answer 28

infectious agents such as bacteria, protozoa, nematode and cestode larvae

Question 29

What is degeneration of skeletal muscles?

Answer 29

only a segment of the myocyte is effected

Question 30

What is necrosis of skeletal muscle?

Answer 30

the entire myocyte is effected

Question 31

What lesions are associated with skeletal muscle degeneration and necrosis?

Answer 31

diffuse paleness or pale streaks, swollen, hyalinized, fragmented sarcoplasm, mineralization of the sarcoplasm, and myoglobinemia and myoglobinuria

Question 32

What can cause skeletal muscle degeneration/necrosis?

Answer 32

ischemia, bacterial toxins, and associated hydrolytic enzymes, and increased intra-sarcoplasmic [Ca]

Question 33

What can cause an increase in intra-sarcoplasmic [Ca]?

Answer 33

membrane damage, dysregulation of Ca gating, coagulation of the sarcoplasm

Question 34

What is muscular dystrophy?

Answer 34

inherited progressive myodegeneration and myonecrosis

Question 35

What causes muscular dystrophy?

Answer 35

a defective dystrophin gene

Question 36

What is malignant hyperthermia?

Answer 36

an inherited defect in Ca-gating regulation leading to an uncontrolled release of Ca from the sarcoplasmic reticulum

Question 37

What lesions does malignant hyperthermia cause?

Answer 37

acute myodegeneration and myonecrosis

Question 38

What triggers episodes of malignant hyperthermia?

Answer 38

stress and halothane

Question 39

What is an example of neuromuscular dysregulation?

Answer 39

myasthenia gravis

Question 40

What is acquired myasthenia gravis?

Answer 40

an autoimmune disease that destroys the acetylcholine receptors on the myocyte and myoneural jjunction

Question 41

What is inherited myasthenia gravis?

Answer 41

an patient is born with an inadequate number of acetylcholine receptors on the myocyte

Question 42

What is skeletal muscle segmental regeneration?

Answer 42

degenerated segments of skeletal muscle are removed by macrophaes and replaced by satellite cells

Question 43

What is skeletal muscle fibrosis due to?

Answer 43

significant inflammation, necrosis, and hemorrhage

Question 44

What is osseous metaplasia of skeletal muscle?

Answer 44

woven bone production

Question 45

What is osseous metaplasia secondary to?

Answer 45

hemorrhage

Question 46

What neoplasias occur in skeletal muscles?

Answer 46

rhabdomyoma, rhabdomyosarcoma, fibrossarcoma, and infiltrating lipomas

Question 47

What is the function of tendons?

Answer 47

they are the origins and insertions of muscles

Question 48

What are tendons composed of?

Answer 48

type I collagen

Question 49

What lesions are associated with tendons?

Answer 49

contracted tendons, traumatic tear/rupture, tendinopathy, and tenosynovitis

Question 50

What are contracted tendons?

Answer 50

a congenital defect frequently associated with in utero neuromuscular maldevelopment

Question 51

What results as traumatic tear/rupture to the tendons?

Answer 51

hemorrhage

Question 52

How does traumatic tear/rupture heal?

Answer 52

via fibrosis - it is replaced with type III collagen

Question 53

What is tendinopathy?

Answer 53

abnormality in extracellular glycosaminoglycan

Question 54

What exudate is associated with tenosynovitis?

Answer 54

serous to fibrinopurulent exudate

Question 55

What can cause tenosynovitis?

Answer 55

trauma and bacterial infections

Question 56

If chronic, what can cause as a result of tenosynovitis?

Answer 56

adhesions