Lecture 3,4 and 5 terms Flashcards
1
Q
Skeletal system - what is it?
A
The skeletal system includes the bones of the skeleton and the cartilages, ligaments and other connective tissues that stabilise or interconnect them.
2
Q
What are the functions of the skeleton?
A
Support, movement, red blood cell formation, protection and storage of minerals and lipids
3
Q
BullShit MPS (politicians have SKELETONS in their closet) - What is this acronym for?
A
Functions of the skeleton - Blood cell formation, Storage, movement, protection, support
4
Q
Two types of bone tissue
A
Compact and cancellous bone
5
Q
Cancellous bone
A
Also known as trabecular bone. Light and spongy bone that looks more disorganised (lots of fibres in different direction to deal with forces). This is a shock absorbing structure. It resists and channels forces that come from multiple directions. Spongy bone consists of an open network of struts and plates that resembles lattice work. Spongy bone is found in the inside of most bones.
6
Q
Compact bone
A
Strong bone that is good at transmitting force in one direction (for example down its length). It is a dense organised looking bone.
Compact bone forms the outer layers and diaphysis of long bones
7
Q
Long bones
A
These bones are longer than they are wide (elongated and slender)
Composed of wider epiphyses and a longer, narrower diaphysis
Act as levers for motion
These bones are mostly limb bones like the femur (levers are what muscles act on hence long bones are in limbs)
8
Q
Short bones
A
These bones are close to equal width and length, they are small and boxy and often rounded or squared in appearance.
These bones are weight bearing (from multiple directions).
Made from mostly cancellous bone (taking weight from a bunch of different directions)
Examples include carpels and tarsals
9
Q
Epiphysis
A
Distal and proximal ends of bone which make up joints (end parts of a long bone)
Made from cancellous bone
Covered in hyaline cartilage
Contain red marrow between trabeculae
The epiphysis consists largely of spongy bone. Spongy bone consists of an open network of struts and plate that resembles lattice work with a thin covering of compact bone
10
Q
Metaphysis
A
A narrow zone that connects the epiphysis with the shaft of the bone
11
Q
Diaphysis
A
Shaft of the bone (shaft or central part of a long bone) (long and tubular)
Compact bone (thicker bone in diaphysis)
Contains yellow marrow
Has blood vessels and nerves
Relatively dense compact bone makes up the walls of the diaphysis. It forms a sturdy protective layer around the central space.
12
Q
Flat bones
A
The function of flat bones is usually for muscle attachment and also for protection of underlying soft tissues.
Made up of thin plates of compact bone and some cancellous too.
Example skull (protection by providing a complete encasement of organ (brain)) and scapula (muscle attachment)
13
Q
Irregular bones
A
These are bones that don’t fit into any other category normally.
Complex shapes with short, flat, notched or edged surface e.g. vertebrae, pelvis
Various functions and shapes.
Often have a foramen/foramina (holes)
Made of thin layers of compact bone surrounding a spongy interior
14
Q
Axial skeleton
A
The bones of the main axis of the body : cranium, spinal column and thorax( rib cage).
Function - protection of vital organs
15
Q
Appendicular skeleton
A
The skeleton of the appendages (limbs).
Function - movement and fine motor function
16
Q
Skull
A
Part of the axial skeleton
Consists of a number of bones of which all except the mandible (lower jaw) are fixed immovably together after infancy. i.e. the cranium and the facial bones (the cranium and facial bones are seperate structures)
17
Q
Cranium (vault)
A
Part of the skull
This bone’s role is to give protection to the brain therefore the bones are robust.
Serves as a place for muscle attachment, larger muscles can attach due to robustness.
18
Q
Facial bones
A
Part of the skull
Protects and supports sensory organs.
Generally small, brittle and irregularly shaped
19
Q
The vertebral column
A
Part of the axial skeleton
Spine - composed of 24 individual vertebrae together with the sacrum and coccyx.
Keeps the trunk upright, lots of muscle and ligament attachments.
Supports head - it is balanced in the upright position
20
Q
Divisions of the vertebral column and why they are named differently?
A
Cervical (7) Thoracic (12) Lumbar (5) Sacrum Coccyx Named differently due to different shapes of the vertebrae
21
Q
Ribcage (thoracic cage)
A
Consists of the ribs, sternum
Known as the thoracic cage as it articulates with the thoracic vertebrae (12 vertebrae= 12 ribs)
Role is to protect the heart and the lungs. Therefore there must be some movement possible because the lungs need to inflate and deflate. This means its joints to the vertebral column are sliding joints that allow a little bit of movement. Ribs are able to slide with a little bit of room when breathing.
22
Q
Describe the upper and lower limb structure
A
Single proximal long bone - Humerus (upper) / Femur (lower)
2 distal long bones - Radius and ulna (upper) / Tibia and fibula (lower)
23
Q
Divide the upper and lower limbs into their general parts
A
Arm and forearm (upper)
Thigh and leg (lower)
24
Q
How has bipedalism affected the form of the skeleton?
A
The human skeleton is the shape it is because form is related to function. We are bipedal therefore the lower limbs need to be formed to provide movement and stability. We are hands free meaning that are hands are not involved in locomotion. Less stability in the upper limbs but instead they are more mobile and are adapted for precision.
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Humerus and femur in terms of relationship to bipedalism
With bipedalism this means that…
Humerus is shorter and lighter
There is deeper articulation for proximal femur than proximal humerus
All because of stability versus movement
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Mobile forearms and wrists versus stability of legs
Mobile forearms and wrists
Pronation/supination radius and ulna
Shape of distal articulation for wrist mobility
More sliding is possible in wrist joint
Stability of legs
NO pronation or supination
Tibia is very robust for weight bearing
Ankle joint is stable
27
Hands
Carpals (8) per hand
Metacarpals (5) per hand
Phalanges (3 per finger) but in thumb only (2)
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Foot
Tarsals (7) per foot
Metatarsals (5) per foot
Phalanges (3) in each toe except 2 phalanges in the big toe
29
What is a girdle?
Girdles are attachment points, wrapping the appendicular skeleton to the axial skeleton
30
Pectorial girdle
The pectorial girdle consists of the clavicle and the scapula. Pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side.
Clavicle - a stabilising strut, pushing the shoulder blades back allows for more motion.
Scapula - Freemoving and is used for muscle attachments. Allows for more mobility due to sliding motion.
31
Pelvic girdle
The pelvic girdle consists of the hip bones (2) and the sacrum. It attaches the axial skeleton to the lower limbs. All the force of the body is coming down the vertebral column, to pelvis to be distributed into the lower limbs. The pelvic girdle is responsible for lots of weight-bearing.
32
What is the hip bone made up of?
The hip bone is made up of 3 seperate bones which fuse together as a child - the ilium, pubis and ischium
33
Male versus female pelvis
There is sexual dimorphism displayed between the male and female pelvis.
The female pelvic cavity is more circular (like a cylinder) and the pelvic outlet is more open and wide in females. This maximises space for childbirth and it makes it easier to birth a big brained baby.
Females have a larger sub-pubic angle indicating a wider sub-pubic arch to males.
Females have a shorter, straighter sacrum compared to the male pelvis which has a more curved and longer sacrum.
34
Describe bone tissue composition
Bone is a connective tissue. It supports other tissues/organs and helps to maintain form. It doesn’t have a lot of cells, mostly ECM which is everything that isn’t cells (fibers etc.)
Bone has two extracellular components - an organic and an inorganic component (without one you lose a key functional aspect of bone)
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Ground substance
Made up of proteoglycans, these sugars attract water molecules which provides bone with the ability to withstand compression.
36
Describe the organic part of bone
The organic part of bone is made up of proteins.
33% of the bone matrix is organic.
Consists of collagen (protein) which exists in fibres in different orientations (criss cross structure) surrounded by a ground substance.
Ground substance is made of proteoglycans
The function of the organic part of bone is to resist tension, if it was removed then the bone would be very brittle and would be able to be broken easier.
37
Describe the inorganic part of bone
The inorganic part of bone is the mineral component.
67% of the bone matrix is inorganic.
Consists of hydroxyapatite and other calcium minerals (mineral salts). The mineral component of bone makes bone hard and resistant to compression. When removed, the bone becomes too flexible.
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Summary of what makes up the bone (simply)
Cells+inorganic+organic = bone
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What cells make up the bone?
osteogenic cells, osteoblasts, osteocytes and osteoclasts (Both compact bone and spongy bone contain the same four types of cells.)
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What percentage does the cellular component of bone make up of the bone matrix?
2%
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Osteogenic cells
Osteogenic cells are stem cells that produce osteoblasts. Osteogenic cells are found in the inner, cellular layer of the periosteum.
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Osteoblasts
Cells involved in the production of bone. These cells later differentiate into osteocytes. Located wherever new bone is forming. Their precursor is osteogenic cells. Osteoblasts produce new bone matrix in a process called ossification. Osteoblasts make and release the protein and other organic components of the matrix. Before calcium salts are deposited, this ‘pre-bone’ organic metric is celled osteoid. Osteoblasts also help increase local concentration calcium phosphate to the point where this calcium salt is deposited in the organic matrix. This process converts osteoid to bone. Osteocytes develop from osteoblasts that have become completely surrounded by bone matrix
43
Osteocytes
Mature osteoblasts.
Maintainers and communicators - recycle proteins and minerals from the matrix. Also control activity of the osteoblasts/clasts
The precursor of osteocytes are osteoblasts which become embedded in the osteoid.
Osteocytes are mature bone cells that maintain the bone matrix. These cells continually recycle the protein and minerals of the surrounding matrix. Osteocytes secrete chemicals that dissolve the adjacent matrix, and the released minerals enter the bloodstream. They then rebuild the matrix, stimulating the deposition of mineral crystals. The turnover rater varies from bone to bone. Osteocytes also take part in the repair of damaged bone. The thin layers of matrix are called lamellae. Osteocytes make up most of the cell population in bone. Each osteocyte occupies a lacuna, a pocket sandwiched between layers of matrix. Osteocytes cannot divide, and a lacuna never contains more than one osteocyte. Processes of the osteocytes extend into narrow passageways called canaliculi that penetrate the matrix. The canaliculi interconnect the lacunae and reach vascular passageways, providing a route for nutrient diffusion.
44
Osteoclasts
Cells involved in the destruction of bone
Remove bone matrix to maintain new healthy bone. These cells secrete enzymes and acids to dissolve the bone matrix which causes bone remodelling. These cells are located wherever bone reabsorption is occurring.
Osteoclasts are not related to osteogenic cells or their descendants. Instead, they are derived from the same stem cells that produce monocytes and macrophages, cells involved in the body’s defence mechanisms
45
What is the structure of compact bone?
Osteon structure
46
What is the structure of cancellous bone?
Trabecular structure
47
What is an osteon?
Longitudinal (lengthwise) unit within compact bone.
Cylindrical structure on a microscopic scale that runs down the length of your long bones.
48
What does an osteon provide?
Provides a pathway for nutrients to get to cells in the extracellular matrix
The function of an osteon is to maintain osteocytes by providing nutrients to them
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Central canal
Contains blood vessels and nerves. This is the main way that nutrients are received.
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Lamellae
Thin rings of compact bone, between which are found the lacunae.
Lamellae are tubes of ECM with collagen fibres which are aligned to resist forces. These make up the osteon, and are arranged to form a series of cylinders running longitudinally down the shaft of the compact bone
The lamellae of each osteon form a series of nested cylinders around the central canal. In transverse section, these concentric lamellae resemble a target, with the central canal as the bullseye.
51
Interstitial lamellae
Interstitial lamellae fill in the spaces between the osteons in compact bone. These lamellae are remnants of osteons whose matrix components have been almost completely recycled by osteoclasts during the process of bone remodelling.
52
Circumferential lamellae
Found at the outer and inner surfaces of the bone, where they are covered by the periosteum and endosteum, respectively. These lamellae are produced during the growth and maintenance of the bone.
Layers of bone matrix that go all the way around the bone.
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Lacunae
Microscopic spaces in bone and cartilage in which cells (osteocytes) are found. (‘lakes’ for osteocytes). These cells need a blood supply therefore use canaliculi. Lacunae house individual osteocytes
54
Canaliculi
Canaliculi are small channels that connect the lacunae housing the osteocytes together are also connects to the central canal. These allow communication between the osteocytes and the spread of nutrient. (Canaliculi radiating through the lamellae interconnect the lacunae of the osteon with one another and with the central canal.)
55
Describe cancellous bone structure
Found where bones are not heavily stressed or where stresses arrive from many different direction. The trabeculae are orientated along stress lines and are cross-braced extensively. Spongy bone is much lighter then compact therefore it reduces the weight of the skeleton, making it easier for muscles to move the bones. Spongy bone makes up most of the volume of short, flat and irregular bones and the epiphyses of long bones. In spongy bone, lamellae are not arranged in osteons. The matrix in spongy bone forms struts and plates called trabeculae. The thin trabeculae branch, creating an open network. There is no vasculature in the matrix of spongy bone. Nutrients can reach the osteocytes by diffusion along canaliculi that open onto the surfaces of trabeculae. Spongy bone within the epiphyses of long bones, such as the femur, and the interior of other large bones such as the sternum and ilium contains red bone marrow. At other site, spongy bone may contain yellow bone marrow. Blood vessels within this tissue deliver nutrients to trabeculae and remove wastes generated by the osteocytes.
Where there is crossing over of line of stress, there will be a point of weakness in the bone. This is a likely place for the deterioration of trabeculae.
Marrow fills the cavities between the trabeculae. There are no blood vessels - The blood supply is from the medullary cavity (the red marrow)
This bone is synthesised outwards
56
Why trabecular bone? (in cancellous bone?)
Organisation of trabeculae (in a criss cross formation) resists force from multiple directions. Directs force from the body weight in a single direction down the shaft made of compact bone. This bone spreads force distally
57
Pelvic girdle force distribution ....explain
The trabeculae channel weight around the ilia into the femurs. This is a large weight bearing structure, carries the weight of the entire upper body from the vertebrae round laterally to where your femur articulates and down your lower limb. The trabeculae are mostly orientated to lead the weight from the vertebral column around the curve of your pelvis and into your femur, taking the weight and supporting it as it goes through your body.
58
What is appositional growth?
Appositional growth is the increase in the diameter of bones by the addition of bony tissue at the surface of bones. Osteoblasts add bone matrix in lamellae to bone surface. This adds successive layers of circumferential lamellae to the outer surface of the bone. Osteoblasts trapped between these lamellae differentiate into osteocytes. Over time, the deeper lamellae are recycled and replaces with the osteons typical of compact bone. As bone is being added to the outer surface through appositional growth, osteoclasts are removing and recycling lamellae at the inner surface. As a result, the medullary cavity gradually enlarges as the bone increases in diameter.
Osteoblasts at the bone surface secrete bone matrix, and osteoclasts on the inner surface break down bone.
59
Why is bone remodelling useful?
Because it allows bones to grow and respond to pressures around them.
If we have a lot of forces acting on our bones then we want them to get larger and wider, to deal with the force and to get wider bones they go through appositional growth.
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Bone homeostasis
Bone is constantly being formed and destroyed. This allows our body to mobilse calcium, phosphate and other minerals from the bone matrix.
Remodelling allows bones to respond to stress and trauma (shape change possible to resist strain etc.)
Balance of bone destruction and formation means that the amount of bone stays the same (the same volume) (when are bones are grown)
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What happens if bone homeostasis is not maintained? What are the requirements to maintain bone homeostasis?
Body has requirements to maintain homeostasis such as adequate calcium in diet, moderate exercise (if no exercise then the body doesn’t know the forces that it needs to respond to). Without these, there can be an imbalance between osteoblastic/osteoclastic activity.
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Osteopenia
Destroying more bone than you are forming. This happens to everyone as you get older. The osteoblastic activity decreases and the osteoclastic activity increases.
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Osteoporosis
If osteopenia gets worse/extreme i.e. clinically significant amount of bone density loss (visible on radiographs). Compact bone is eaten away from the medullar cavity by the osteoclasts which are still super active and the osteoblasts are not making any new bone or as much as usual. Therefore the thickness of compact bone decreases. The trabeculae in cancellous bone become thinner.
People usually present with compression fractures of vertebrae as most of the vertebrae is made up of cancellous bone.
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Risk factors of osteoporosis
Women are more at risk - loss of oestrogen post-menopause (estrogen is linked to osteoclastic activity.
Lifestyle factors - lack of exercise, nutritional factors, smoking/drinking
Dependent on your bone mass start point - Peak bone mass is in your 20s so it ideally needs to start high.
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Cartilage model
Bones begin as a cartilage model, chondroblasts are formed which produce cartilage.
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Endochondral ossification (explain)
The process of transforming cartilage to bone. Endochondral ossification involves the replacement of hyaline cartilage with bony tissue. Most of the bones of the skeleton are formed in this manner. When bone formation begins in the embryo some 6 weeks after fertilisation, all exisiting skeletal elements are made of hyaline cartilage. These cartilages are gradually replaced by bone through the process of endochonral ossification. Key steps below …
Step 1 - As the cartilage starts to become more dense, it starts to calcify/get a mineral component
Step 2 - As it gets larger and a little more calcified, blood vessels start to form around the outside of that cartilage model. Blood vessels are important because they bring with them osteoblasts and with that you get osteoblastic activity starting to occur on the outside of the cartilage and secreting that bone matrix. Now a thin layer of actual bone is outside the cartilage.
Step 3 - As we get older and this process moves further alone, the blood vessels start to penetrate into the cartilaginous model, it goes through a forming and into the centre of this cartilage model so that we can now get osteoblasts into the centre of this model and bone can be formed in the middle.
Step 4 - Process continues until the diaphysis/shaft starts to look like adult bone. This shaft ossification is called our primary ossification centre, place where bone starts to become actual bone and is always present in the shafts of long bones.
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Primary centres for ossification
A primary ossification centre is the first area of a bone to start ossifying. It usually appears during prenatal development in the central part of each developing bone. In long bones the primary centres occur in the diaphysis/shaft and in irregular bones the primary centres occur usually in the body of the bone. Will turn into bone from the shaft outwards.
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Secondary ossification centres
A secondary ossification centre is the area of ossification that appears after the primary ossification centre has already appeared – most appear during the postnatal and adolescent years. Most bones have more than one secondary ossification centre. In long bones, the secondary centres appear in the epiphyses. Has the same ossification process as primary centres. It is separated from the diaphysis by an epiphyseal plate, also called the growth plate because this structure being in place means that our bone is able to grow length wise.
Starts with the same process as your primary ossification centres. Start out with blood vessels around the outside, the sides of the epiphysis, and then the laying down of bone externally. Then you get blood vessels into the centre and bone starting to be laid down internally and this works its way outwards until you have a much larger epiphyses.
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Epiphyseal plates
Hyaline cartilage that unites an epiphysis with the shaft of a long bone and is the site where the bone grows in length - growth or epiphyseal plates
Having the cartilage between your epiphysis and diaphysis means that your diaphysis can extend outwards as you grow and then once finished growing the epiphysis can fuse to it
These disappear from the body when growth is completed.
The growth plates provide a convenient means of allowing growth of a long bone without distorting the intricate shape at the joint surface
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Difference between primary and secondary ossification centres...
The first center that appears is called the primary ossification center; its ossification usually begins in utero, and in long bones it corresponds to the diaphysis. Most secondary ossification centers appear after birth, and in long bones they correspond to the epiphyses.
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How do bones grow in length?
Through the growth plate/epiphyseal plate which allows increase in length as you grow
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How do bones grow in width?
Appositional growth -Osteoblast activity produces circumferential lamellae.Osteoclasts mould the bone shape and form the medullary cavity
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What is a joint?
The areas where 2 or more bones articulate
| Hold bone together, and they do not necessarily have to be mobile (some allow movement and some stop/control movement)
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What are the soft tissues associated with joints?
```
Different compositions depending on function (to allow smooth movement over one another or holding bones together)
Have no inorganic component
Cartilage
1 - Hyaline (articular)
2- Fibrocartilage
```
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General cartilage composition
Collagen (which makes up most of cartilage) fibres in a ground substance, chondrocytes (mature cartilage cells) in lacuna.
Blood vessels do not penetrate the cartilage. Nutrients are diffused through matrix by joint loading (any weight-bearing exercises induce more nutrients).
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Describe the blood supply to cartilage ...
Unlike bone, cartilage does not have blood vessels going into it, this is quite significant because blood vessels help with the healing process and bring nutrients. Blood vessels not going into the cartilage means that it is slow to heal and to get nutrients it must diffuse from the rest of the body, joint loading allows this to happen. Joint loading is putting weight on your joints so the more you do with your joints the more nutrients that come in and therefore the healthier the cartilage is going to be.
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Hyaline (articular) cartilage
A type of cartilage that is very smooth and is found on the articular surfaces of bones.
Collagen fibres are barely visible (they are very small/fine and in a web).
There is high water content in the matrix. Water means that it is very resistant to compressions and so it moulds around pressure.
Provides a smooth and frictionless surface which means that bones aren’t going to catch on one another when moving over each other.
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Function of hyaline (articular) cartilage in joints
Moulds surfaces of bones where they articulate. Allows frictionless and smooth movement. However, hyaline cartilage degrades with age which results in smooth movements becoming less smooth as bones are starting to rub on each other.
Hyaline cartilage is high in collagen, a protein that is found not only in connective tissue but also in skin and bones, and helps hold the body together. Hyaline cartilage provides support and flexibility to different parts of the body.
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Fibrocartilage
A type of cartilage, with a dense matrix of collagen fibres (collagen fibres form bundles throughout the matrix which are all orientated in the same direction). Orientation of fibres aligns with stresses coming at that cartilage. Fibrocartilage’s function is to resist compression AND tension.
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Functions of fibrocartilage in joints
Generally at articulations that experience both compression and tension like the knee joint (menisci).
Found in the soft tissue-to-bone attachments
In joints, fibrocartilage acts as a buffer/ shock absorber - distributes force over a wider area. It is a very structured tissue so it can be used to build the stability of a joint. The fibrocartilage being able to reduce tension means that it can withstand forces coming obliquely too as it has orientation of fibres in different places.
81
Structures associated with joints
Ligaments and tendons - Made of DFCT (made of dense bundles of fibres), which contains collagen, elastin (similar fibre to collagen but a little weaker and a little stretchy) and fibroblasts (cell that synthesises the extracellular matrix and collagen). The function of these structures is to resist tension. Some vascularity but minimal compared with bone - very slow healing after injury
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Ligaments
A band of dense fibrous connective tissue binding bones together at joints. Ligaments join bone to bone. Their function is to restrict movement (away from themselves) and this is done with tightly aligned collagen fibres). They have minimal elastin as they are mostly made of collagen as it is stronger.
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Lateral ligament restricts...
Adduction
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Medial ligament restricts...
Abduction
85
Tendons
A band of dense fibrous connective tissue that connects muscle to bone. Its function is to facilitate and control movement. Tendons have more elastin content than ligaments (still have collagen) to allow a little bit of stretichness in movement.
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How do the amount of bony congruence affected the amount of soft tissue support? What is bony congruence?
Bony congruence is the sum of the bone surfaces that form an articulation. Less bony congruence means that more soft tissue support is needed.
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Tissues versus structures
Tissues - how cells are grouped together in a highly organised manner according to specific structure and function
Structures - something formed of a tissue
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Fibrous joints
This is the least mobile of all the joints. Fibrous joints are connected by dense connective tissue consisting mainly of collagen. These joints are also called fixed or immovable joints because they do not move (allow minimal to no movement). Fibrous joints have no joint cavity and are connected via fibrous connective tissue.
Tissue it is made up of is DFCT, structure of these is a ligament which are short and limit movements at them. The function of these joints is to limit movement and to provide stability
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Distal tibiofibula joint
This is an example of a fibrous joint. You do not want movement in this joint due to the lower limbs needing more stability and all of our weight being on this structure. The DFCT is restricting movement and if this movement was able to occur then standing and stability would be greatly affected.
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Cartilaginous joints
Allow more movement between bones than a fibrous joint, but less than the highly mobile synovial joint.
The tissue they are made up of is fibrocartilage
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Intevertebral disc
This is an example of a cartilaginous joint. This structure is in-between vertebrae and it allows a little movement and acts as a shock absorber. As you go down your vertebral column, bearing more weight as you go down, the intervertebral discs get bigger as more weight is placed on each inferior vertebral body. These discs are present in order to resist compression and transmit force between these structures.
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Pubic symphysis
A cartilaginous joint that sits between and joins the left and right superior rami of the pubic bones.
It is a cartilaginous joint (made up of hyaline cartilage and fibrocartilage). Allows there to be a little more give for childbirth. Its role is to resist compression, distribute force and hold the shape of the pelvic area.
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Pubic arch
Part of the pelvis. It is formed by the convergence of the inferior rami of the ischium and pubis on either side, below the pubic symphysis. The angle at which they converge is known as the subpubic angle.
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Sacrum
A triangular shaped bone at the base of the vertebral column, formed usually by five fused vertebrae.
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Coccyx
The tail bone, attached to the sacrum. A short bone.
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Bone cells respond to ...
External forces (remodels based on how you use your skeleton)
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What is the extracellular matrix?
The extracellular matrix (ECM) is a three-dimensional network of extracellular macromolecules, such as collagen, enzymes, and glycoproteins (produced and secreted by the cells into the surrounding medium), that provide structural and biochemical support to surrounding cells.The ECM is the non-cellular portion of a tissue.
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Describe compact bone macroscopically
Outer surfaces seem dense, structured and impenetrable (periosteum)
Foramina/holes for blood supply
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How does the compact bone look on a microscopic level?
Made up of circumferential lamellae and units called osteons
100
Describe how the blood supply works in cancellous bone
No blood supply is connected (there is not central canal/blood vessel) however blood is able to diffuse. This is because the trabeculae are so thin, the nutrients are able to directly diffuse from the marrow that is in-between the trabeculae. The canaliculi, the little holes on the surface are drawing a blood supply directly from the red marrow. Because they are a thinner structure, just diffusion is used, this can’t happen in compact because it is so dense/thick it needs an internal supply.
101
The more white that is showing up on an x-ray means greater the...
bone density
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Endosteum
Thin connective tissue/membrane which lines the inside of the marrow cavity which contains osteoblasts to build the bone. (it is not made of DFCT)
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Endosteum vs periosteum
Periosteum refers to a dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints while endosteum refers to a layer of vascular connective tissue lining the medullary cavities of bone.
Periosteum is made of DFCT whereas the endosteum is not.
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Periosteum
Protective fibrous connective tissue covering bone surfaces, except on articular surfaces of joints. Carries blood vessels and nerves to the bone.
Thick sheath of dense irregular connective tissue covering the bone surface
Perforating fibres hold the periosteum to bone
105
Why is it important that your epiphyses do not attach to the shafts of you long bones?
It is really important that your epiphyses do not attach to the shafts of your long bones mainly because if they did your shafts would not be able to grow.
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When does bone growth finish and what happens?
It finishes at puberty and the epiphyses start to fuse with the diaphysis
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What does the growth plate turn into?
The growth plate turns into bone
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What type of cartilage is menisci and why is it helpful in the knee joint?
Fibrocartilage - it is helpful because they can act as shock absorbers and resist compression that is always coming down the knee with the weight of the upper body.
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Does cartilage have a blood supply? What does this mean if you injure your cartilage?
No it does not and it means that injuries to cartilage have long healing times
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How does the menisci distribute force?
Force is distributed through the menisci as well as straight down. The menisci acts as a cushion and spreads the force.
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In fibrocartilage, the alignment direction of fibres aligns with ...
The direction that the stresses are coming at that cartilage.
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What is DFCT and what is it made of?
Dense fibrous connective tissue (DFCT) contains compact, strong, inelastic bundles of collagenous fibres arranged in parallel.Has a glistening white appearance. Found in tendons, ligaments, capsules and periosteum and is able to withstand tension.
113
What are fibroblasts?
A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues.
114
Collagen vs elastin
Collagen and elastin are two fibrous proteins in the connective tissues. ... Collagen provides strength to the body structures whereas elastin provides a snapback property to the body structures.
Elastin is far more flexible but not as strong as collagen. Collagen imparts toughness and strength to a connective tissue as well as a little bit of flexibility but not much.
115
Collagen
Collagen is the main structural protein in the ECM in various connective tissues in the body.
116
Elastin
Elastin is a key protein of the FCM. It is highly elastic and present in connective tissue allowing many tissues to resume their shape after stretching or contracting.
117
In the ankle, the lateral ligament restricts ____ and the medial ligament restricts _____
Adduction (inversion)
Abduction (eversion)
118
Hip joint and knee joint comparison in terms of bony congruence
Hip joint- Ball of the femoral head being cupped by your acetabulum (socket) on your hips. Lots of bony articulation at a hip joint therefore there is not as much soft tissue needed to support as there is a lot of bony support.
Knee joint - In a joint with less bony congruence, like the knee joint where the femur is just sitting on top of the tibia, there is not very good bony congruence and therefore there needs to be a lot of soft tissue support in order to keep this joint stable.
119
Describe in detail this function of the skeleton - support
Structural support for the whole body
Individual bones or groups of bones provide framework for the attachment of soft tissues and organs
120
Describe in detail this function of the skeleton - movement
Bones are levers that can change the magnitude and direction of the forces that the skeletal muscles generate. (allows the muscles to have something to pull on)
121
Describe in detail this function of the skeleton - red blood cell formation
In the red bone marrow (fills the internal cavities of many bones) and the skeleton also assists in the formation of white blood cells and platelets
122
Describe in detail this function of the skeleton - protection
The skeleton protects major organs from the forces that they are exposed to.
123
Describe in detail this function of the skeleton - storage of minerals and lipids
Calcium salts in bone are a valuable mineral reserve that maintains normal concentration of calcium and phosphate ions in blood. Calcium is the most abundant material in the body. Bones contain adipose tissue which stores lipids as energy reserves.
124
Name the bone classes
long, short, flat and irregular bones
125
Draw on skull where the coronal and sagittal sutures are...
google image if required
126
Cranial sutures
Example of a fibrous joint. These provide stability for brain case as you do not want the brain to be subjected to movement and changes in pressure.
127
Pelvic inlet
The superior circumference forms the brim of the pelvis, the included space being called the pelvic inlet.
128
Pelvic outlet
The pelvic outlet is formed by the lower border of the pubic bones at the front, and the lower border of the sacrum at the back.
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Subpubic angle
The subpubic angle (or pubic angle) is the angle in the human body formed at pubic arch by the convergence of the inferior rami of the ischium and pubis on either side.
130
Medullar cavity
The medullary cavity or marrow cavity, is a space within the hollow shaft. In life, it is filled with two types of bone marrow. Red bone marrow is highly vascular and involved in the production of blood cells. Yellow bone marrow or adipose tissue is important as an energy reserve.
131
Describe the force distribution in the femur...
Force is coming in from multiple direction at the proximal epiphysis, it gets led in one direction down our compact bone and then it diffuses out at the joint surface, at the distal epiphysis so that al the pressure is not coming in one place to the joint.
132
Describe the level of organisation that makes up an organ system from smallest to largest ...
Atom, proteins, cells, tissues, organ and then organ system
133
What is a spine on a bone?
any short prominence of bone
134
What is a ramus on a bone?
The curved part of a bone that gives structural support to the rest of the bone. Examples include the superior/inferior pubic ramus and ramus of the mandible.
135
What is a fossa on a bone?
A depression or hollow usually in a bone
136
As you go down the vertebral column, what happens?
As you go down, the amount of weight needing to be supported increases therefore the size of the vertebrae increases (larger in size inferiorly)
137
How many individual, unfused vertebrae are there in total?
24 vertebrae
138
How many ribs make up the rib cage?
24 (12 on each side) (12 thoracic vertebrae!)
139
How many ribs attach by costal cartilages to the sternum?
20 (10 on each side)
140
Which bones does the clavicle articulate with?
Sternum and scapula
141
Which bones does the scapula articulate with?
Clavicle and humerus
142
Epicondyle
A projection on the condyle
143
Condyle
A rounded prominence at the end of a long bone
144
Main difference between condyle and epicondyle ...
The main difference between condyle and epicondyle is that condyle forms an articulation with another bone. whereas epicondyle provides sites for the attachment of muscles.
145
Bump on the medial posterior aspect of the wrist is which bone?
Ulna
146
Which bones do the hip bones articulate with anteriorly, laterally and posteriorly...?
Anteriorly - the other hip bone
Laterally - the femur
Posteriorly - the sacrum
147
Patella
The patella (kneecap) is a flat, circular-triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint.
148
Malleolus
A malleolus is the bony prominence on each side of the human ankle.
The medial malleolus, felt on the inside of your ankle is part of the tibia's base
The posterior malleolus, felt on the back of your ankle is also part of the tibia's base
The lateral malleolus, felt on the outside of your ankle is the low end of the fibula
149
What difference can you see between leg bones and the bones of the forearm?
The tibia and fibula are larger and longer and do not cross over each other like the radius and ulna do. Both the ulna and the radius articulate with the humerus whereas only the tibia articulates with the femur.
150
How many phalanges are there in total in the human body (upper and lower limb included)?
56
| ((4x3)x4)+(4x2)) = 56
151
In women, the cartilage in the pubic symphysis can soften under the influence of certain hormones? When and why might this be useful?
It would be useful when a woman is pregnant and during childbirth as it will allow the pubic bones to move apart to let the baby’s head come through.
152
What two things make up the pelvis?
Hip bones and the sacrum
