Movement Flashcards
1
Q
Functions of the skeletal system (5)
A
- support
- movement
- protection
- storage
- RBC formation
2
Q
Two types of bone tissue
A
- compact
- cancellous
3
Q
Where is compact bone found?
A
Where strength and load bearing is needed
4
Q
Where is cancellous bone found?
A
Where shock absorption is required.
5
Q
Bone classes
A
Long bones
Short bones
Flat bones
Irregular bones
6
Q
Describe long bones
A
- longer than they are wide
- shaft or diaphysis
- extremities or epiphyses
- function as levers for movement
- thicker compact bone in diaphysis
7
Q
Function of long bone
A
- function as levers for movement
8
Q
Describe short bones
A
Near equal in with and length
- weightbearing/shock absorption
- mostly cancellous bone.
9
Q
Function of short bones
A
- Weightbearing/shock absorption.
10
Q
Describe flat bones
A
- thin plates of compact bone - some cancellous (eg ridges for muscle attachment)
11
Q
Function of flat bones
A
- Protection - cranial bones
- muscle attachment - scapula
12
Q
Describe irregular bones
A
Variable shape and function
eg vertebrae
13
Q
2 Divisions of the skeleton
A
- Axial
2. Appendicular
14
Q
Bones of the axial skeleton
A
- Skull
- Vertebral column
- Rib cage
15
Q
Bones of the skull
A
- cranium (cranial vault)
- facial bones
- mandible
16
Q
Bones of the vertebral column
A
- cervical (7)
- thoracic (12)
- lumbar (5)
- sacrum (5 fused) and coccyx (2-5 fused)
17
Q
Bones of the rib cage
A
- ribs
- sternum
18
Q
Bones of appendicular skeleton
A
- limbs
- regions: arm, forearm, thigh, leg
19
Q
Main function of lower limb
A
Stability and locomotion (bipedal)
20
Q
Main function of upper limb
A
Manipulation and mobility
21
Q
Structure of limbs
A
- single proximal long bone
- two distal long bones
- hands and feet
22
Q
2 limb attachment points
A
- pectoral (shoulder) girdle
- pelvic girdle
23
Q
Bones of pectoral girdle
A
- clavicle
- scapula
24
Q
Bones of pelvic girdle
A
- hip bones (2)
- sacrum (axial)
= pelvis
25
Function of pectoral girdle
For motility
26
Function of pelvic girdle
For stability
27
What is the pelvic girdle designed for
Limited movement for stability due to incoming forces from above.
- cope with locomotion.
28
Structure of hand
8 carpals
5 metacarpals
5 x 3 phalanges (2 phalanges in thumb)
29
What is the hand designed for
Manipulation and fine movements
30
Structure of the foot
7 tarsals
5 metatarsals
5 x 3 phalanges (2 in big toe)
31
What is the fit designed for
- weight transfer
- stability
- elongated lever for assisting with locomotion.
32
Two bones of ankle joint
Articulation between tibia and talus.
33
Properties of Bone Tissue
- bone has cells
- bone grows
- bone remodels
- bone can repair itself
34
What type of tissue is bone tissue
Connective tissue
35
What are the two extracellular components of bone tissue
- organic
| - inorganic
36
How much of bone tissue is organic?
33%
37
How much of bone tissue is inorganic?
67%
38
What are the organic components of bone tissue
- collagen (protein) (in fibers)
| - ground substance (proteoglycans)
39
What is the function of organic component of bone tissue
Resist tension
40
What happens to bone if there isn't the organic component
If collagen is removed -> brittle/breaks easily
41
What is the inorganic component of bone tissue composed of
- hydroxyapatite (mineral salts)
42
What is the function of inorganic component of bone
- resist compression (due to hardness) as one of the function of the bone is to support.
43
What happens if the inorganic of bone is removed
Mineral removed -> bone too flexible
44
What are the cellular components of bone
- Osteoblasts
- Osteocytes
- Osteoclasts
45
Function of OB
Build ECM
46
Function of Ocytes
Mature bone cells (for communication in remodelling process)
47
Function of OC
Break down ECM
| - multinucleated
48
Similarities in composition of compact and cancellous bone
Made of same material but organised in different was microscopically.
49
Compact bone at a gross level
- outer surfaces seem impenetrable
| - foramina/holes (towards ends)
50
Function of foramen in bone
Provide nutrient to cells trapped at compact level to maintain cells
51
Structures in compact bone at a microscopic level
- osteon
- lamellae
- central canal
- lacunae
- canaliculi
52
Describe osteon
Longitudinal cylinder within compact bone.
| - lamellae form a series of cylinders running longitudinally down shaft = osteon
53
Describe lamellae
Tubes of ECM with collagen fibres aligned to resist forces
54
Function of osteon
Maintain OC by providing nutrients
55
Function of lamella
Form a series of cylinders running longitudinally down shaft = osteon.
56
Describe central canal
Blood vessel and nerves
57
Describe lacunae
Lakes for Ocytes
58
Describe canaliculi
Channels for Ocytes thru ECM
59
Arrangement of collagen fibres in lamellae
Fibres in different directions to resist tensile forces
60
Describe periosteum
Fibrous connective tissue sheath around bone
61
Describe subperiosteal surface of bone
Surface of the bone where blood vessels penetrate
62
Describe the remodelling process
- Osteoclastic front: osteoclasts come in through and destroy ECM, resulting in a void
- osteoblasts come and build ECM
63
Structure of cancellous bone
- trabeculae -> struts of lamellae bone
- marrow fills the cavities
- osteocytes housed in lacuna on surfaces of trabeculae
64
Function of cancellous bone
- resist compressive forces and shock absorption
- trabeculae in areas for shock absorption
- aligned in certain ways to diffuse forces
65
Describe the zone of weakness
Forces coming from superior = strengthening on inferior part of neck to try to resist those forces.
- leaves area with less trabeculae to provide strength -> zone of weakness.
66
Describe the path of force from upper body to hip
Come from above, through sacrum, then joint between sacrum and pelvis, then hip bone, then neck of femur, then down shaft.
67
What is ossification
The process of transforming cartilage to bone
68
What does bone begin as
A cartilage model
69
Where is the primary centre of ossification
Diaphysis or shaft
70
Where is the secondary centre of ossification
Epiphysis
71
What are growth plates/epiphyseal plates made of
Cartilage
72
What is the process of bone formation
- cartilage cells transformed into bone (bone formation spreading essentially from the centre to the ends) and destroyed by osteoblasts
- the cartilage model then develops a periosteum that soon enlarges and produces a ring, or collar, of bone.
- bone is deposited by OB, which differentiate from cells on the inner surface of the covering periosteum/
- Soon after the appearance of the ring of bone, the cartilage begins to calcify, and a primary ossification centre forms when a blood vessel enters the the rapidly changing cartilage model at the midpoint of the diaphysis
- endochondreal ossification progresses from the diaphysis toward each epiphysis, and the bone grows in length -> INTERSTITIAL GROWTH
- secondary ossification enters appear in the epiphyses, and bone growth proceeds toward the diaphysis from each end.
- bone tissue formed at bottom of growth plate
- until bone growth in length is complete, epiphyseal plate remains between each epiphysis and the diaphysis
- during periods of growth, proliferation of epiphyseal cartilage cells brings about a thickening of this layer.
- Ossification of the additional cartilage nearest the diaphysis follows - that is, osteoblasts synthesise organic bone matrix, and the matrix undergoes calcification.
As a result, the bone becomes longer.
- it is the epiphyseal plate that allows the diaphysis of a long bone to inc in length.
73
How does the epiphyseal plate allow growth in length
= layer of cartilage between epiphysis and diaphysis
- during periods of growth, proliferation of epiphyseal cartilage cells brings about a thickening of this layer
- ossification of the additional cartilage nearest the diaphysis follows - OB synthesis organic bone matrix, and the matrix undergoes calcification
- as a result, the bone becomes longer.
74
4 layers of cells of epiphyseal plates
- top layer closest to the epiphysis composed of "resting" cartilage cells. These cells are not proliferating or undergoing change. This layer serves as a point of attachment firmly joining the epiphysis of a bone to the shaft.
- Proliferating zone. Composed to cartilage cells that are undergoing active mitosis. As a result of mitotic division and increased cellular activity, the layer thickens and the plate as a whole increases in length.
- zone of hypertrophy is composed of older, enlarged cells that are undergoing degenerative changes associated with calcium deposition.
- layer closest to diaphysis = thin layer composed of dead or dying cartilage cells undergoing rapid calcification. As the process of calcification progresses, this layer becomes fragile and disintegrates. The resulting space is soon filled with new bone tissue, and the bone as a whole grows in length.
75
How do bones get wider
OB in periosteum
| - OB lay down new bone on outside of shaft
76
How do bones get moulded into shape
OC from endosteum mould the bone shape and form the medullary cavity
77
What is bone pathology
An imbalance of OC or OB activity
78
What is Osteoporosis
When OC's overtake OB's
79
What is a symptom of osteoporosis in compact bone
Compact bone becomes thinner and porous
80
What is a symptom of osteoporosis in cancellous bone
Loss of volume
| - compression fractures of vertebrae
81
Causes of osteoporosis
- ageing-loss of oestrogen
- lifestyle factors:
- lack of exercise: exercises stimulates normal bone remodelling process
- nutritional factors: diet high in Ca2+ is important
- peak bone mass - bone as a bank: reach peak bone mass in 20's, must maintain.
82
Components in Stage 1 of fractures
- haematoma -> blood clot
- capillaries -> capillaries invade site and bring phagocytes
- phagocytes -> clean up debris (broken bone, soft tissue)
83
Components in stage 2 of fractures
- fibroblasts -> formation of soft callus
- chondroblasts (from differentiation of fibroblasts) -> form a pro callous made of cartilage = biological splinting
- chondro = cartilage
- fibrocartilaginous callus (procallus)
84
Components of stage 3 of fractures
- bony callus -> OB invade cartilaginous callus and turn it into bone
- osteoblasts
- ends are now held together by bone
85
Components of stage 4 of fractures
- remodelling
- bone callus disorganised ("new bone").
- remodelled osteoblasts network of nature bone
- remodel so the can't see callus at all in children but in adults can see callus.
86
How long does it take for bony callus to form in child
6 weeks
87
What is pseudoarthrosis
False joint
- due to no fixation of ends of bones
- ends of bones continue to move on each other
88
3 types of fractures
- Closed, simple
- open, compound
- greenstick
89
Describe closed simple fracture
- break in bone but not too much rotation/displacement of bone ends on each other
- minimal soft tissue damage
90
Describe open compound
- displacement of bone ends -> lots of space between bone ends
- bone may penetrate skin
- lots of soft tissue damage (muscles, nerves)
- if bone actually goes out of skin -> prone to infection
91
Describe green stick fracture
- not a complete fracture (whereas there is complete discontinuation in closed and open)
- more common in children (as their bone is not as mineralised as still growing)
92
What is an articulation
Where bones meet
93
What is a joint?
- hold bones together
- involves bone shapes and soft tissues
- allow free movement or control movement
94
What are the soft tissues made of
- Have no inorganic component
| - cartilage: hyaline and fibrocartilage
95
Examples of structures made of hyaline cartilage
- nose
- not between sternum and ribs
- cartilaginous model
96
Describe general cartilage composition
- collagen fibres in a ground substance (for resisting tension)
- chondrocytes live in lacuna
- nutrients diffused through matrix by joint loading - not vascular
97
Why is cartilage made of collagen fibres
For resisting tension
98
Describe the structure of hyaline cartilage
- collagen fibres barely visible
| - high water content in matrix
99
Function of hyaline cartilage
- resist compression
| - provide smooth frictionless surface
100
Structure of fibrocartilage
- collagen fibres form bundles throughout matrix
| - orientation of fibres aligns with stresses
101
Function of fibrocartilage
Resist compression AND tension
102
Function of hyaline cartilage in joints
- to provide frictionless movement of bones in synovial joints
- moulds to surfaces of the bones where they articulate
103
How can hyaline cartilage degrade
- with age
| - trauma
104
Function of fibrocartilage
- concave discs of fibrocartilage
- deepens articulation at knee
- can adapt its shape to stresses on joint in movement
105
eg of fibrocartilage
- meniscus at knee joint
| - between vertebral bodies.
106
What is bony congruence
the sum of the bone surfaces that form an articulation
107
Relationship between bony congruence and amount of soft tissue support
Less BC = more soft tissue support
108
What are ligaments and tendons made of
- DFCT
- collagen
- fibroblasts(cytes)
109
Function of ligaments and tendons
Resist tension
110
Are ligaments and tendons vascularised
Some vascularity but minimal compared to bone.
| - very slow healing.
111
Which structures do ligaments join
- bone to bone
112
Function of ligaments
- restrict movement
- movement is restricted "away from itself"
eg lateral restricts adduction
eg medial restricts abduction
113
Which direction is movement restricted form in ligaments?
Away from itself.
114
Which structures do tendons join
- muscle to bone
- inserts into bone
- muscle shortens, pull on tendon = pull on bone = produce movement.
115
Function of tendons
- facilitates and controls movement
| - contraction
116
How is ligament inserted
- fibres insert into bone tissue
| - zone of calcification where ligament turns into bone
117
How are tendons inserted
- muscle merges with periosteum first and then into bone tissue.
- area of mineralisation between bone and muscle
118
3 types of joints
- fibrous joints
- cartilaginous joints
- synovial joints
119
What are fibrous joints made of
Tisse = DFCT
120
What is the difference between tissue and structure
Tissue is the material that makes up structure eg ligament
121
What is the structure of fibrous joints
Ligament
122
Function of fibrous joints
Limited movement. For stability.
| - find where greater stability is required. Don't want bones to move
123
Where is the ligament in fibrous joints
Directly between 2 bones and articulates and joints them together.
124
Examples of fibrous joints
- Cranial sutures: stitch-like, short joints between bones of cranial vault.
- main function is to protect brain and therefore don't want cranial bones to move.
- in between bones are short, strong joints made of DFCT
- in distal tibiofibula joint
- cements bones together with DFCT
- weight thru body and ankle, and therefore don't want to move apart: inefficient and vulnerable to injury
eg between root of teeth and jawbone
125
What are cartilaginous joints made of
Tissue = fibrocartialge
126
How much movement do cartilaginous joints allow
Some allowed and required
127
Function of cartilaginous joints
- fibrocartilage resists compression and tension
- find in parts of body where there are compressive forces and some movement between bones
- special functions and various structures
128
Another name for Fibrous joints
Synarthroses
129
Another name for cartilaginous joints
Amphiarthroses
130
Another name for Synovial joints
Diarthroses
131
Examples of cartilaginous joints
eg intervertebral disc: joint between vertebral bodies
- nucleus pulposis that rolls around as we move
- disc is attached to bone by a ligament
eg pubic symphysis: joint between 2 pubic bones in pelvis
- anterior joint of pelvis girdle
- in between 2 bones -> disc of fibrocartilage -> cartilaginous joint
- some movement allowed for both M and F as all of the forces are going through the posterior part of the pelvic girdle.
- forces through torso, joints between sacrum and pelvic
- need stability
- but forces still go through the anterior art of the pelvic girdle
- if had fibrous joint joint, which does not allow ANY movement, any diffusion of forces -> vulnerable to injury.
- for females, in 3rd trimester. Hormonal release: relax joint and opens up during childbirth slightly.
132
How much movement do synovial joints allow
- free-moving
- in most joints of the limbs except eg distal tibiofibula joint
- to allow free movement/locomotion and manipulation
133
What is the function of synovial joints
to allow locomotion
- facilitation of free movement (of bones over each other as we move)
AND
- control of movement where we want to restrict some movement
134
General structure of synovial joints
Complex association of tissues and structures
- all of the different tissues present in some way
- cartilage: hyaline and fibrous
- DFCT
135
What determines the range of movement possible at a joint
Bone end shape
136
Describe the femoral head and the range of motion it allows
- round projecting head of femur
- completely encased in socket of pelvic bone
- allows all types of movement: angular and rotation
- deep articulation = high bony congruence and therefore is stable
- less soft tissue support of the knee is required due to high bony congruence
137
Describe the femoral condyles and the range of motion it allows
Articulation from femural condyles onto flat surface of tibia
- meniscus (made of fibrocartilage) deep articulation and help with accomodating lack of bony congruence and deepening articulation to increase stability
- lot of soft tissue support outside around and inside too.
138
Where is articular cartilage found
covers bone ends where they articulate AND move over each other.
139
Is subchondral bone smooth
Yes. (under articular cartilage)
- outside has foramen
- roughened where ligaments and muscles attach
140
Why do condyles project at the back
to allow full flexion and extension
| - at the back there is smooth bone covered in articular cartilage
141
What are the two types of ligaments
Capsular and intracapsular
142
Describe capsular ligaments
- primary ligament
- like a sleeve
- holds bones together: articulates and joints 2 bones together
- tight & thick wire more support is required
- loose on sides where movement is allowed -> loose and thin at a more mobile joint.
- eg in shoulder joint -> very loose and thin joint capsule & therefor support must come form other structures (aka muscles in shoulder)
- eg knee: thick on lateral and medial but loose and thin on posterior and anterior
- potential space/cavity allows movement over each other.
- synovial membrane lines the inner surface of the capsule
- secretes synovial fluid -> lubrication of joint
143
Describe the structure of synovial joint
- joint capsule (goes from one bone, around bone ends to insert into other bone)
- synovial membrane lies the joint capsule
- articular cartilage around bone ends
- cavity/potential space
- synovial fluid (helps with movement in potential space). Lubricates joint
- there may be fibrocartilage which deepen articulation, like meniscus
- muscles around helps hold femural head.
144
Describe structure of capsular ligament
- thickening of capsule where more support is required
145
Draw a labelled diagram of a synovial joint
.
146
Describe the collateral ligaments of the knee
- medial restricts abduction
- lateral restricts adduction
- a ligament restrict movement away from itself
147
Function of intracapsular ligaments
- restricts movement between bones
eg knee: specifically stop femur from moving anteriorly or posteriors on the tibia.
- when walking, tibia wants to move from side to side.
- collateral ligaments placed medially and literally to stop adduction and abduction.
- therefore only flexion/extension are allowed.
148
Are intracapsular ligaments part of the capsule
No. It's inside the capsule
149
Where is the origin of intracapsular ligaments
Arise (originate) from tibia and insert into femur.
| - cross over each other in knee
150
How are the intracapsular ligaments in the knee arranged?
- Anterior cruciate crosses posterior and insert into posterior parts
- Posterior cruciate ligament inserts into anterior part of femur between two condyles
151
how do the cruciate ligaments restrict movement of femur?
- Anterior cruciate restricts posterior displacement of femur
- posterior cruciate restricts anterior displacement of femur.
152
Why are cruciate ligaments important for going up stairs, down/up steep slope etc
Femur wants to slide posteriorly off femur going up
| Femur wants to slide anteriorly off femur going down
153
How is the intracapsular ligaments usually damaged
From external forces -> fixation of tibia but rest of body keep moving.
154
What are menisci made of
Fibrocartilage
155
What is the fibrocartilaginous menisci important for
Deepening articulation between femur and tibia, and diffusing compressive forces.
156
Main difference between fibrous and cartilaginous joints, and synovial joints
- in fibrous and cartilaginous joints, tissue forming structures inside between bones -> glue bones together to either: stop movement entirely, or allow some movement
- in synovial joints, the joint capsule goes from one bone to another bone and leaves those bone ends free to move over each other.
- dependent on how much movement is allowed and where it needs to be restricted depends on where it is around the joint.
157
What are bursae in the knee
Small sacs filled with synovial fluid, which act to protect the structures inside the knee, reducing friction as they slide over each other when the joint is moving.
158
What is a fibrous joint made of
Two bones are held together with collagen.
- collagen fibres allow little, if any, movement
- no cartilage
- no fluid-filled joint cavity
159
What is a cartilaginous joint made of
The ends of the bones in a cartilaginous joint are covered with a thin layer of hyaline cartilage, with the bones being connected by tough fibrocartilage.
- the whole joint is covered by a fibrous capsule usually.
- do not allow much movement but they can "relax" under pressure, so giving flexibility to structures such as the spinal column
160
What is a synovial joint made of
The bones are covered by hyaline cartilage and separated by a fluid.
- the joint cavity is lined by a synovial membrane and the whole joint is enclosed by a fibrous capsule.
161
Give an example of sesamoid bones
Patella
- irregular, but appear singularly
162
Atlas
C1
163
Axis
C2
164
How to name phalanges
Distal and Proximal and Middle
165
Structure of Osteocytes
- giant
| - multinucleic
166
What's another name name for Central canal
Haversian Canal
167
What's another name for transverse canal
Volkmann's Canal
168
What else is damaged in an open fracture
- damaged muscle and nerve damage
eg can see bone through skin = penetrated skin
169
How long does it take for a fracture to heal
6 weeks
170
How many carpals and tarsals
8 and 7
171
What do long bones function as
Levers for movement
172
What do flat bones function as
- protection eg ribs and sternum, cranial bones
| - muscle attachment (eg scapula)
173
What do short bones function as
Weight bearing/shock absorption
174
Example of sesamoid bone
Patella
175
What is the organic component of bone used for
- growth, repair, remodelling, support
176
What is the organic component of bone made of
- Collagen
| - ground substance of proteins secreted by CT cells.
177
Function of osteoblasts
- bone forming
- make and secret osteoid (organic matrix)
- made by stem cells in the endosteum
178
What is osteoid
Organic matrix
179
Where are OB made
By stem cells in the endosteum
180
Function of OC
- giant, multinucleate
- erode bone minerals, which are reabsorbed into blood
- many mitochondria and lysosomes
181
Where are osteocytes
Embedded in matrix in lacunae
182
What are Ocytes
Mature, non-dividing OB
183
Structure of OC
- many mitochondria and lysosomes
184
Describe the process of endochondral ossification
1. Periosteum develops and enlarges, producing a bone collar
2. Blood vessels penetrate into diaphysis - centre of ossification
3. fibroblasts in blood differentiate into OB and begin to reproduce spongy bone at the primary center
4. Bone formation spreads along the shaft
5. continuous remodelling occurs creating a marrow cavity
6. secondary ossification enters form when capillaries and osteoblasts migrate into the epiphyses, which are soon filled with spongy bone
7. a proliferating epiphyseal plate of hyaline cartilage remains at the metaphysics
185
Describe the epiphyseal plate
- responsible for lengthening of bones
- chondrocytes (Cartilage cells) proliferate
- OB synthesise organic matrix and it calcifies
- when epiphyseal cartilage cells stop dividing and the cartilage completely ossifies, bone growth ends - epiphyseal cartilage disappears.
186
How does growth in bone width occur
Osteoclasts enlarge diameter of medullary cavity
| Osteoblasts from periosteum build new bone
187
Describe osteoporosis
- increased bone porosity
- reduced mineral density and mass
- vertebral bodies for example are very susceptible to damage due to high percentage of cancellous bone
- osteoporotic bone is more susceptible to fractures
- more common in menopausal women believed to be due to the decreased production of oestrogen.
188
Process of bone healing
1. blood vessel tears - vascular damage initiates repair process
- hemorrhage and blood pooling forms a hematoma
- granulation tissue forms - made of inflammatory cells, fibroblasts, bone and cartilage forming cells, new capillaries
2. fibroblasts and chondroblasts form cartilaginous tissue (fibrocartilaginous callus)
- procallus (soft callus)
- soft callus with the in growth of granulation tissue
3. Osteoblasts from bony callus - binds broken ends of fracture like a splint. (stability allows healing to proceed)
- hard callus with in growth of cartilage and bone
4. bone remodelling
- hard callus with bone remodelling.
189
Describe hyaline cartilage
- most abundant
- bluish due to high water content of matrix
- matrix of collagen and ground substance (rich in chondroitin sulphate)
- resists compression
- frictionless movement of bones
- degrades with age
190
Which type of cartilage is most abundant?
Hyaline
191
Describe elastic cartilage
- elastic fibers for elasticity
| - collegen for tensile strength
192
Examples of elastic cartilage
- external ear
- epiglottis
- eustachian tubes (connect middle ear to nasal cavity)
193
Describe fibrocartilage
- little matrix
- lots of collagen
- fibers align with stresses
- strong, rigid, dense connective tissue
- resists compression and tension
194
Examples of fibrocartilage
- pubic symphysis
- intervertebral discs
- menisci (increase bony congruence).
195
Does fibrocartilage have LITTLE matrix
yes
196
What are fibrous joints made of
DFCT
197
What are fibrous joints
- articulating surfaces fit closely together
- fixed or limited movement
- eg skull sutures (become ossified in older adults)
198
What are cartilaginous joints made of
- hyaline or fibrocartilage
199
Describe cartilaginous joints
limited movement
| - eg pubic symphysis - slight movement during childbirth
200
What are synovial joints made of
Articular cartilage
201
Describe synovial joints
- freely movable joints
- most numerous
- most mobile
- most anatomically complex
202
Most numerous type of joint
Synovial
203
What's the ECM made of
```
Extracellular matrix (ECM)
Solvent (water, ions)
Proteins
Collagen – strength
Elastin – elasticity
Glycoproteins – bind cells to ECM
Fibronectin
Laminin
```
204
Human Tissue Act, 2008
Bequest: a body donated for study purposes
Informed consent given by the donor
Living spouse/relatives can override deceased person’s wishes
No limit to how long body parts are kept
Body to be treated ethically
205
RMP is dependent on
The concentration of ions on either side of the membrane
| The permeability of membranes
206
Role of insulin and glucagon in the blood glucose feedback system
Insulin produced by beta cells -> blood glucose conc dec
| Glucagon produced -> blood glucose conc inc
207
C & C Hormonal vs Neuronal Comunication System
Neuronal:
- fast
- specific
- good for rapidly changing conditions
- good for brief responses
- action potential in axons and neurotransmitter release at synapses
Hormonal:
- targeting by expression of specific receptors on target cells
- relatively slow but long lasting
- hormones released into blood
- good for widespread, sustained responses.
208
Determinants of Range of movement
1. shape of articulating bone surfaces
2. ligament, tendon and muscle location and length
3. body surface contact.
209
Structure of a synovial joint (components)
- bone ends
- articular cartilage: dampen mechanical forces. Allows movement over each other
- capsule: a continuation of periosteum where fracture healing takes place. Consist of collagen
- cavity: not a cavity. Filled with synovial fluid.
- synovial membrane: consist of synoviocytes producing synovial fluid -> constant production. Synovial fluid is also reabsorbed by the synoviocytes.
- ligaments: guide motion of joint. ACL and PCL
- intracapsular ligaments: cruciate ligaments
- meniscus: inner and outer on knee. Distribute load in whichever position. Consists of cartilage
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Bursa
A synovial membrane filled with synovial fluid
| - found in shoulder joint
211
Function of bursae
Serves as cushioning
- at surfaces when tendons running through joints
- comparable to joint cavity.
- enclosed structure
212
What is a synovial joint designed for
Movement
213
Recess
Cavities formed by the joint capsule
214
Factors that limit movement
- Ligaments limit range of movement in certain joints
- muscles can also limit
- geometry of bony ends - most important - and cartilage on top
215
What do intracapsular ligaments serve as (2 functions)
- stabilisers
- proprioreceptive function: realised how situated in space. Nerve fibres in ligament of joints and in receptors of the respective joint capsules
216
Shape of condyles
- less inclined at the front
- bending and getting up -> largest forces at posterior
- difference in geometry generate load peaks -> meniscus distribute load evenly.
217
What is movement a balance between
Stability and mobility
| - trade off between the 2
218
Compare shoulder and hip joint
hip has lower range of movement as need stability compared to shoulder joint. (for locomotion)
- therefore shoulder joint dislocated more often than hip joint
219
What is range of motion determined by
- bone end shape
- ligament location and length
surface surface contact -> creating a counter force on either side (lots of overlap at femoral head and hip socket compared to shoulder joint: 20% contact as the shoulder joint is designed for mobility.
220
What is the instrument for measuring ROM
Goniometer
221
What is a goniometer
Used for measuring range of movement
222
Different types of synovial joint shapes
- hinge
- pivot
- saddle
- ellipsoid
- condylar
- plane
- ball and socket
223
Uniaxial joints
- hinge
| - pivot
224
Biaxial joints
- saddle
- ellipsoid
- condylar
225
Multiaxial joints
- plane
| - ball and socket
226
Hinge joint
Uniaxial
- flexion and extension
eg
- ankle
- elbow (jumpers with ulna)
- interphalangeal joints
- refined, guided movement by ligaments on either side and surface of cartilage
227
Pivot joint
Uniaxial
- rotation: supination and pronation
- radioulnar joints
- C1 and C2: atlas and axis. C2 sticks inside C1 -> allows rotation
- ligaments guide movement
- muscle around radius head allows for movement (proximal)
228
Saddle joint
only found in one region
- biaxil
- flexion/extension
- adduction - abduction
- circumduction
Obligatory rotation opposition
eg carpometacarpal joint
base of thumb
provides huge stability
229
Ellipsoid joint
- bixaxial
- flexion/extension (can be done to a larger degree than adduction and abduction)
- adduction/abduction - towards ulna and radius
- circumduction
no rotation (very little rotation)
eg wrist joint
- important for load distribution through ellipsoid joint
230
Condylar joint
Biaxial
- flexion - extension
- rotation
eg knee joint - ligaments -> flexion and extension
- temporomandibular joint
- limited range of motion by ligaments or other structures eg bony ends
231
Which cruciate ligament tenses during extension
Posterior
- during flexion the ACL tenses
232
Plane joint
- sliding and gliding
- flat articular surfaces
- intercarpal
- inter tarsal
- limited movement by dense ligaments
- only works if the surfaces are fairly even and fairly flat.
- surfaces that can glide on top of each other.
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Ball and Socket joint
- multiaxial
- flexion/extension
- adduction-abduction
- circumduction
- rotation
eg shoulder
hip
Guided by the long tendons of brachii muscle
Intracapsular ligament in shoulder joint also with proprioreceptive function
234
Describe the glenwood cavity joint
Joint surface at scapula much smaller than joint surfaces on the humeral side that allows for huge range of movement
- shoulder joint
- not only guided by ligaments but also by tendons of muscles
- > by long tendon of biceps brachii
235
What guides the movement of shoulder joints along with ligaments
Long tendon of biceps brachii
236
What is muscle designed for
to contract
237
What affects the function of muscle
Arrangement of fibres
238
3 types of muscles
Skeletal - small striated fibres
Smooth - GI system, eye, other viscera
Cardiac - completely different function and metabolism and microstructure. Merging skeletal and smooth functionalities
239
What is the connective tissue that the muscle cells are wrapped in?
Type 1 collagens
- forms sheaths at all magnifications
- useful to create huge forces
240
What collagen form the layers of connective tissue that wrap around muscle cells?
Type 1 collagens
241
Functions of Skeletal muscle (4)
1. Movement
- to any extent
- eg locomotion
2. Heat Production
- body temperature
- freezing -> shivering from skeletal muscles shaking 20-30Hz. Create a huge amount of heat
- 20-30Hz muscle shaking
3. Posture
- maintained by skeletal muscles
4. Communication
- gestures
- body language
- muscles of face: smiling, looking
- key driver of effective communication
- 80% gestural, 20% verbal.
242
Fascia
Collective term for all connective tissue - in muscle and between muscle
- can be extended to tendons
243
What does muscle extend into
Bone.
| - which consists of collagen (type I) and hydroxyapatite
244
Endomysium
Single muscle fibre wrapped in
245
Perimysium
Fibre bundles wrapped in
- important for blood: arteries and veins
- region where blood supply travel through
246
Epimysium
wraps muscle all around
247
How long is one muscle fibre
up to 40mm
248
How are muscle fibre arranged
Parallel
Cylindrical
Striated - protein arrangement (repeat arrangement of proteins)
249
Are muscle cells single or multi nuclei
Multinuclear
- cells merged so more than 1 nuclei
- nuclei not in middle of cell
- pushed aside otherwise in way of contractile mechanism
250
2 key proteins in muscle cells
Actin and myosin
| - enable muscle contraction -> fibres merged into a composite called sacromere
251
two key metabolites for muscle cells
ATP and Ca2+
252
What are actin and myosin
2 key proteins in muscle cells
253
What are ATP and Ca2+ for muscle cells
key metabolites
254
What is a sarcomere
Actin and myosin merged into one functional composite.
- segment of myofibril between 2 successive Z discs
- each sarcomere function as a contractile unit
- A bands of sarcomeres appear as relatively wide, dark stripes (cross striae) under the microscope, and they alternate with narrower, light-coloured stripes formed by the I bands
255
Components of muscle cells
Myocyte
Myofibril
Myofilaments in sarcomere (thick and thin proteins)
Sarcomere = protein arrangement
256
Length of sarcomere
2 µm
257
How is the sarcoplasmic reticulum specialised
For liberate Ca2+ upon to facilitate muscle contraction
258
How are sarcomeres arranged
end-on-end along myofibril in length
- Z line
- boundaries of sarcomere
- link actin filaments
- composed of myosin and actin
- sarcomere framed by actin
- reaching towards the other side of the sarcomere
- cannot change length
- myosin in middle
- contractile process -> myosin carried into actin ends
259
What is the contractile process of the muscle
Myosin carried into actin ends
260
What do the arms on the myosin do
Under metabolism of ATP to ADP, help muscle fibres to contract
- E dependent mechanism.
261
What is the Z line made by
Connection between sarcomere
262
What is the A line
Whole length of myosin
263
What is the I line
Between the ends of the myosin
264
What happens when muscle shortens
- thin drawn towards each other over thick
- Z lines move closer together (1µm apart)
- oblique to line of pull
265
What does the uni and multipennate arrangement allow
Capable of exerting much larger forces than just arranged longitudinally
266
Important factors for muscle contraction
- actin and mysoin interdigitate (merging with each other)
- actin and myosin retain their length: actin move relative to myosin -> shortening
- process consumes E
- Ca2+ essential
267
What does muscle contraction process consume
Energy
268
What does muscle form determines function. What does it depend on
1. length of muscle fibres - longer = larger lengths. different along different levers.
2. number of muscle fibres -> if really thick -> exert more force eg muscle belly thick
3. arrangement of muscle fibres -> eg pennate manner -> exert more force
269
Which manner of muscle exert more force
Pennate
270
How much can muscle fibres shorten
50% of resting length
271
Where is a large ROM found in
Long muscle fibres: longest in hamstrings and quads
272
1st factor of muscle form
Length of muscle fibres
273
2nd factor of muscle form
number of muscle fibres
274
What is tension directly proportional to
Cross sectional area
275
Where do muscle originate and insert
Originate from site closer to heart (pro)
| - insert at distal
276
Relationship between number of fibres, SA and tension
- greater number of fibres = greater SA = greater tension
277
What is pennate
When fibres are oblique to muscle tendon
= more fibres into same space
- oblique to line of pull (uni, bi, multi)
278
2 types of cross sectional areas
- anatomical and physiological
279
Advantage of oblique arrangement
Higher cross sectional areas -> exert higher forces
280
Are relaxed muscles slightly active
Yes
281
How is the activity of relaxed muscle produced
Delivered by certain amount of nerve activity -> heat production 20-30Hz
282
What happens if nerves didn't innervate muscles
Hypotrophic
| - even atrophic
283
What is the substance that is released from the synaptic terminal of motor neurone
Acetyl choline
| terminal ends of nerve fibres - release neurotransmitter
284
What is the effect of ACh
Depolarise muscle cell to the effect that Ca2+ is liberated
285
What happens when Ca2+ is released as a result of ACh depolarising the cell
helps sarcomeres to contract
286
Which substances help sarcomere to contract
Ca2+ and ATP
287
Does muscle tone produce movement
No
288
Properties of muscle tone
- does not produce movement
- keeps muscles firm and healthy
- helps stabilise joints and maintain posture
- keep muscle metabolically active. If immobilised -> hypertrophic -> loss of protein eg after removing cast
289
Importance/function of muscle tone
- Keep muscles firm and healthy
- helps stabilise joints and maintain posture
- keep muscle metabolically active. If immobilised -> hypertrophic -> loss of protein eg after removing cas
290
2 fibre types
Fibre type I
| Fibre type II
291
Fibre Type I
high enzyme activity
| - aerobic, slow-twitching -> marathon runners
292
Fibre type II
Low enzyme activity
- anaerobic, fast-twitching -> sprinters
- many contractions in a short time
293
Can there be more than one muscle type in a single muscle
Yes
| eg both Fibre type 1 and fibre type 2 muscles in a muscle. Can change ratio over time due to training etc
294
Components of the Motor Unit
- myofibril
- myofibril
- myofilaments in sarcomere: composed of thick and thin proteins
- sarcolemma
- T-Tubules
- Sarcoplasmic reticulum
295
Sarcomere
protein arrangement
296
Function of Sarcoplasmic reticulum
Store Ca2+, which allows muscle contraction
297
3 connective tissues around muscle fibres
- Endomysium
- Perimysium
- Epimysium
298
Which is the key structure to allow vascular and nerve supply
Perimysium
| - allow for sliding of muscle fascicles relative to each other
299
Which connective tissue of muscle allow for sliding of muscle fascicles relative to each other
Perimysium
300
Where are the nuclei in muscle fibres
Pushed aside
- if in middle, prevents proper contraction
- therefore merged, as a functional unit
- so more than 1 nuclei for each fibre.
301
Key proteins in myofilament
Actin (thin) and thick (myosin) proteins
302
What is the motion of the musculosystem mainly based on
proteins: muscles, tendons, ligaments
303
Which muscle fibre type doesn't contract as often
Fibre type I (high enzyme activity) -> marathon runners
304
What is the fascia
Extension of muscle towards other muscles/structures
- a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches, stabilizes, encloses, and separates muscles and other internal organs.
305
What is muscle function largely driven by
Nerve action
306
Where do axons extend down to
- terminate at proximal insertions
| - save protein and make muscle contract as fast as possible
307
Feedback mechanisms of neuromusclar junction
feedback provided by spinal nerve (root ganglion)
- receives feedback of how muscles are situated in space
- proprioreceptor
- signals integrated to tendons and muscles via nerves articulated in spinal root ganglion.
308
Where is the spinal nerve
Slightly outside of spinal cord
309
Route of an excitation
Most nerve cells that generate an excitation sit at the ventral root of spinal cord
- must travel all the way down to the muscle they innervate with axons
- but only go as far as proximal insertion of a muscle begins
- go as proximal as possible
- to increase the velocity of signal transduction and to save material within axons in neurons
310
Where do most nerve cells that generate an excitation sit?
Ventral root of spinal cord
311
Difference between ventral and dorsal root
The ventral roots (anterior roots) allow motor neurons to exit the spinal cord. The dorsal roots (posterior roots) allow sensory neurons to enter the spinal cord.
312
What is a dorsal root ganglion
a cluster of nerve cell bodies (a ganglion) in a dorsal root of a spinal nerve. The dorsal root ganglia contain the cell bodies of sensory neurons
313
Why do the axons terminate as proximal as possible?
To inc velocity of signal transduction and to save material within axons in neurons
314
How can muscle movement be refined
How fast the axons are firing
315
Are axons myelinated
Yes.
316
Motor endplate
the large and complex end formation by which the axon of a motor neuron establishes synaptic contact with a skeletal muscle fiber (cell)
317
How is a stimulus transferred
Electrical -> Chemical -> Electrical
318
Process of sending a stimulus at the axon
- electric simulus via axon being transmitted to chemical at synaptic cleft and then back to electrical at skeletal muscle cells.
- tiny vesicles to release compounds into synaptic cleft -> ACh
- another transmission by polarisation -> muscle contract
- When nerve impulses reach the end of a motor neuron fiber, small vesicles release a neurotransmitter, acetylcholin (Ach), into the synaptic cleft
- Diffusing swiftly across this microscopic gap, acetylcholine molecules contact the sarcolemma of the adjacent muscle fiber.
- There they stimulate acetylcholine receptors and thereby initiate an electrical impulse in the sarcolemma.
- The process of synaptic transmission and induction of an impulse is called excitation
319
What is the neurotransmitter between nerves and skeletal muscle cells (and some smooth)
ACh
320
What is the process of chemical transmission
Diffusion
321
Why have electrical transmission after chemical
Chemical takes a long time, so have electrical transmission on outer surface of axon
322
Why is Ca2+ so important for contraction?
- proteins do not become longer/shorter
- Ca2+ changes the configuration of actin for making protein
- Ca2+ is responsible for the ends of myosin to make movement that allows muscle contractions
- bound within sarcoplasmic reticulum (while muscles not activated and is released upon contraction
323
Why is Ca2+ important for contraction?
Calcium triggers contraction by reaction with regulatory proteins that in the absence of calcium prevent interaction of actin and myosin.
324
Process of muscular contraction
A neural synapse induces an action potential in a muscle cell (fiber) that, in turn, results in calcium ions to be released into the cytosol from the sarcoplasmic reticulum (excitation-contraction coupling) when calcium channels open. Calcium binds to troponin-C to initiate contraction and this will continue until excitation ceases and the molecular calcium pumps in the sarcoplasmic reticulum membrane remove and sequester the calcium.
So the presence of intracellular calcium causes contraction, and its removal allows the muscle to relax.
325
Cellular composition of motor unit
- NMJ
- Sarcolemma
- T-tubules (transport Ca2+, make Ca2+ available for contraction)
- SR
- Ca2+
326
General functions of muscle (plus 2 extra)
- heat production
- posture
- movement
- communication
- cushioning
- protection of vital organs
327
Quadrupedal standing
- broad base of support (low base of support)
- legs flexed at several joints
- energetic expenditure
328
Bipedal standing
- relatively small area of contact with ground
- plantar surface of feet
- energy efficient
- characteristic for very few species
329
What does gravity act as
Act as a agonist or antagonist
- helps to position our body in space
- use gravity as a counterforce eg as a resistance for locomotion.
330
Where is the line of gravity in the sagittal plane
Runs through body
- runs right down in the middle
- redistribute via both hip joint then down to ankles
331
Where is the line of gravity in the coronal plane
- runs through spine
- far behind in the head (type I lever -> keep head lifted)
- spinal column is curved (the line of gravity sometimes run a bit anterior or posteriors to the spine)
- posterior to hip joint
- at the ankle, slightly anterior
332
Hip joint when bipedal standing
- LoG posterior to joint (therefore effect of gravity on the weight of the body tends to extend the hip joints further)
- joint "pushed" into extension
- extension = ligaments are tight = minimal muscle activity needed to hold the joint in extension
333
What is a locked position
Ligaments are tightened
334
Characters of the capsular ligaments of the hip joint
- dense
- do not run straight down
- wrapped around the joint. Curved
- therefore limit the way we externally and internally rotate
- also prevent from falling back by the ligaments being tensed so don't need quad or iliopsoas to contract just when standing.
335
how thick are the capsular ligaments of the hip joint
up to 0.5cm
336
Knee joint when standing
Line of gravity is anterior to knee joint
- when joint locked into position -> line of gravity is close to patella
- slight overextension when standing
- joint "pushed" into extension
- extension = ligaments are tight -> LOCKED = minimal muscle activity needed to hold joint in extension
- PCL really tense when standing -> stable position
- collateral ligaments help to stabilise in extended position too.
337
Ankle joint when standing
Line of gravity is slightly anterior helping it to fall into a dorsal position
- NOT LOCKED because allowing for balance
- plantar flexors of ankle (particularly soleus) are active all the time, providing sufficient tension to withstand the effect of gravity.
- "falls" into dorsal extension
- plantarflexors stabilise
- energy consumed
338
Which joints are not locked when standing?
Ankle
- hip and knee are locked
339
why is the ankle joint not locked when standing
to allow for balance
- lever of the ankle joint to LoG is really long, so only fine movements are necessary for balancing
340
What inserts into calcaneous?
Achilles tendon
341
Which muscle inserts into Achilles tendon
Triceps surae
342
What helps with standing with as little energy as possible
Muscles and ligaments
343
Main features of bipedal standing
- bipedal stance is characteristic to humans
- feet form base of support (plantar surfaces), but insufficient size to provide only balance solution
- bones joints and muscles have special anatomical features to assist balance solution WITH AS LITTLE MUSCLE AND ENERGETIC EFFORT AS NECESSARY
- standing achieved with very little muscular effort - most at ankle joint
344
Characteristics of bipedal (human walking)
- is learnt
- gait is characteristic
- basic pattern is gait cycle
- STANCE phases and SWING phases
- "heel-strike" and "toe-off"
345
What is the stance phase
Foot touches ground and overcome gravity
346
Whats the swing phase
Provide locomotion and move forward.
347
What are the 8 phases
1. initial contact
2. loading response
3. mid stance
4. terminal stance
5. pre-swing
6. initial swing
7. mid swing
8. terminal swing
