Musculoskeletal Flashcards
1
Q
What connects the radius and ulna
A
The interosseous membrane
2
Q
What are the articulation points of the ulna
A
- Troclear notch of ulna –> trochlea of humerus
- Head of ulna –> ulnar notch of radius = radio-ulnar joint
3
Q
What is the wrist called
A
the radiocarpal joint - the radius articulates with 2 of the carpals
4
Q
How many bones make up the carpals
A
8
5
Q
What are the articulation points of the radius
A
- Elbow joint = Radial head + capitellum of the humerus
- Proximal radioulnar joint = radial head + radial notch of ulna
- Distal radioulnar joint = ulnar head + ulnar notch of radius
- Radiocarpal joint = distal radius + scaphoid and lunate
6
Q
What is the most commonly fractured carpal bone
A
The scaphoid from a fall on an outstretched hand
7
Q
What is the order of bones in the hand
A
Capals, metacarpals, phalanges
8
Q
How many phalanges are in the hand
A
3 per finger - proximal, middle and distal
2 per thumb - proximal and distal
9
Q
What passes through the cubital fossa
A
Biceps tendon, median nerve, brachial artery (becomes radial and ulnar), superficial veins - median cubital from which blood is drawn
10
Q
How many muscles are there in the anterior compartment of the forearm
A
8 - in superficial, middle, and deep layers
11
Q
How can the anterior muscles be generalised and what are the exceptions
A
- All flexors, except pronator teres and pronator quadratus
- All innervated by the median nerve, except flexor carpi ulnaris - ulnar
12
Q
Where do the superficial muscles of the anterior compartment of the forearm originate
A
The medial epicondyle
13
Q
What is the medial epicondyle referred to as
A
The common flexor origin
14
Q
What is the middle layer of the anterior compartment of the forearm
A
Flexor digitorum superficials - it gives rise to 4 tendons
15
Q
How many muscles are in the deep layer of the anterior compartment of the forearm
A
3
16
Q
Pattern of number of muscles in the anterior compartment of the forearm
A
4,1,3 - Before I try
17
Q
What does the flexor retinaculum do
A
Stops the tendons from bowstringing
18
Q
What causes carpal tunnel syndrome
A
The compression of the medial nerve from swelling
19
Q
What is the course of the radial and ulnar arteries
A
Radial artery = lateral
Ulnar artery = medial
20
Q
What happens when the radial and ulnar arteries enter the hand
A
The anastomose to form the palmar arches
Superficial = mostly ulnar
Deep = mostly radial
21
Q
What are the two bumps on the wrist
A
Big one = pisiform
Slightly higher, small one = hook of hamate
22
Q
What are the forms of calcium
A
99% bone
1% extracellular
23
Q
How much calcium is there in the body
A
1200mg
24
Q
What molecules regulate calcium level/bone metabolism
A
Calcitriol, parathyroid hormone and calcitonin
25
Calcitriol vs vit D
Calcitriol is the hormonally active form of vitamin D
26
What protein is calcium usually bound to when in the blood
Albumin --> lack of albumin mean free Ca2+ increases
27
Where is parathyroid hormone secreted from
Chief cells in the parathyroid glands
28
What does parathyroid hormone do (calcium)
increase serum Ca2+ levels
29
How does the parathyroid hormone detect Ca2+ levels
Ca2+ sensing receptors
30
What is the action of PTH
Bone: Stimulates osteoclasts, inhibits osteoblasts --> resorption
Kidneys: Increases Ca2+ reabsorption. Increases phosphate excretion --> so it does not combine w Ca2+ to form bone
GI tract: Increases calcidiol gets converted to calcitriol which increases Ca2+ absorption
31
What does Calcitriol do (calcium)
Increase Ca2+ absorption from GI tract
32
What is the action of caclitriol
Increases the number of calcium transporters on wall of GI tract
33
How does pH affect calcium levels
Alkalosis = albumin binds more strongly to Ca2+ --> decreases free calcium levels
Acidosis = albumin binds less strongly to Ca2+ --> increases free calcium levels
34
Where is calcium absorbed
Active via duodenum and jejunum
Passive via ileum and colon
35
Where is the majority of calcium reabsorbed
in the proximal convoluted tubule
36
Where is vitamin D converted to calcitriol
Kidneys
37
What does calcitonin do
Inhibits osteoclasts so decreases bone resorption -> increases Ca2+ levels
(but minor effect)
38
How does cartilage grow
Both appositionally and interstitially
39
What is ossification
the formation of bone
40
What are the 2 types of ossification
1) Endochondrial ossification
2) Intramembranous ossification
41
What is endochondral ossification
hyaline cartilage is created from mesenchyme then replaced with bone
42
What is intramembranous ossification
When bone develops directly from mesenchyme
43
What bones are formed from endochondrial ossification
All bones below the skull except the clavicles
44
What is the process of endochondral ossification
1) Chondrocytes create a hyaline cartilage model of bone
2) Mineralisation occurs (matrix filled with calcium phosphate)
3) Chondrocytes die, creating space in the bone called lacunae
4) Lacunae become filled w osteoblasts which create new bone
45
Where is the primary ossification centre
The shaft of long bones
46
What are growth plates
Ends of bones where cartilage remains so longitudinal growth can continue
47
Process of intramembranous ossification
1) Mesenchymal cells condense into sheets
2) They differentiate into osteoblast precursors and capillaries
3) Osteoblasts deposit calcium phosphate
4) Osteoblasts become osteocytes
5) Compact bone is formed
48
What is modelling drift
The process by which bone becomes wider/curved --> bone remodelling
49
What is osteonal tunnelling
The remodelling of cortical bone - outer layer of long bones- to replace old bone
50
What is the sarcoplasm rich in?
Glycogen
51
What is the size of a myofiber?
Diameter = 1000um
Length = 5cm
52
What cells fuse to produce muscle fibres
Myoblasts
53
What is the order of skeletal muscle structure
Sarcomere --> Myofibril --> Myofiber (muscle cell) --> Sarcolemma --> Endomysium (connective tissue between muscle fibres) --> Perimysium (forms fascicle) --> Epimysium
54
What does titin do
It connects the z line to the m line. Keeps the myosin in the centre and allows the muscle to stretch
55
What does nebulin associate with
actin
56
How many myosin heads are there per myosin filament
300
57
What do tentanus and botulism toxins do
Prevent the release of Ach at the neuromuscular junction
58
Slow oxidative fibres traits
- Aerobic conditions
- lots of mitochondria
- low glycogen content --> ATP source is aerobic respiration
- fatigue resistant
59
How many ATP molecules are produced per glucose for aerobic respiration
38
60
How many ATP are produced per glucose during anaerobic respiration
2
61
What is an exception of the muscle to bone tendon rule
the patellar tendon
62
What are the similarities between tendons and ligaments
- Dense connective tissue in parallel
- Produced by fibroblasts (tenocytes)
- The extracellular matrix makes up 80%
- Poorly vascularised
63
Ligament v tendon
- Ligaments have less collagen
- Ligaments have more elastin
- Ligament fibre organisation is more random
- Blood supply different
64
What has more elastin, ligament or tendon?
Ligament
65
What does the crimping of the ligaments allow
Enables the ligament to increase in length under tension
66
What is the hierarchy of tendon/ligament structure
Tropocollagen --> Collagen molecules --> Microfibril --> Subfibril --> Fibril --> Fibres --> Fascicle --> Endotenon --> Paratenon
67
What is the main component of t + l
Type 1 collagen (95%) + proteoglycans
68
What do proteoglycans do in t+l
Lubrication
69
What is the structure of collagen
- 3 alpha chains coiled individually in a left hand helix
- The 3 individual chains coil together in a right hand helix
70
Where is collagen assembled
extracellularly
71
What is the insertion of a L/T into a bone called
Enthesis
72
Types of enthesis
1) Fibrous insertion = intramembranous ossification via sharpeys fibres
2) Fibrocartilage insertion = endochondral ossification via fibrocartilage, then bone
73
What are the embryological differences between intramembranous to endochondral ossification
Intramembranous ossification = directly ossified
Endochondral ossification = to cartilage then bone
74
How do muscles connect to tendons
- The muscle cells become more convoluted with a larger surface area
- The collagen fibres can then attach in
75
How does tendon/ligament strength increase
Mobilisation - mechanical demands
76
What are the types of joints (structural)
Fibrous, cartilaginous, synovial
77
What are the types of joints (functional)
1) Synarthroses (Fibrous)
2) Amphiarthroses (Cartilaginous)
3) Diarthroses (Synovial)
78
What are examples of fibrous joints
- Sutures = bones bound together by sharpeys fibres. Only in skull
- Syndesmoses = when bones are connected by an interosseous membrane
- Gomphoses = peg and socket joint. Only in tooth articulation
79
Types of cartilaginous joints
1) Synchondrosis = only have hyaline cartilage e.g. costal cartilage
2) Symphysis = includes a plate of fibrocartilage e.g. intervertebral disc
80
What are the 3 types of cartilage
Hyaline (articular), elastic, fibrocartilage
81
What type of collagen is found in cartilage
type II
82
What is the solubility of uric acid
- Poorly soluble in plasma
- Lower the ph, the less soluble
83
What are the sources of purines
- Dietary purines
- Tissue nucleotides
- Purine synthesis
84
Why do men get gout more than women
Oestrogen increases excretion
85
Where are dietary proteins found
- Meat
- Seafood
- Soya
- Oatmeal
86
What is the key enzyme in uric acid formation
Xanthine oxidase (Purine --> Xanthine --> Uric acid)
87
What can high uric acid damage
- Joints
- Kidneys - kidney stones
88
Why can cancer cause increased uric acid levels
Increased tissue breakdown
89
What enzyme recycles purines
HPRT
90
What are the purines
Adenine, Guanine, Hypoxanthine, Xanthine
91
What is the end produce of purine metabolism
uric acid
92
Normal uric acid levels
Men = 200-430 umol/L
Women = 140-360 umol/L
93
D) Fracture
A breach in the continuity of bone
94
What age is peak bone density
30
95
What are examples of metabolic bone diseases
Osteoporosis, Pagets disease, Osteogenesis imperfecta
96
Intra articular vs extra articular fractures
Joint involvement
97
What is the epiphyses of a bone
The end part
98
What are the stages of fracture healing
1) Haematoma (hrs) = bleeding, periosteal stripping
2) Inflammation (days) = platelets, osteoclasts reabsorb dead bone, mesenchymal stem cells
3) Repair (weeks) = callus formation, mineralisation
4) Remodelling (years) = increased bone strength, vascularity
