BMC L12 Flashcards

1
Q

State the 3 types of adult human cartilage

A
  1. Elastic
  2. Hyaline
  3. Fibrocartilage
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2
Q

Describe the structure of hyaline cartilage

A

Amorphous matrix contains chondrin - gelatinous / rubbery substance

Chondrin contains condroitin sulphate
holds incompressible water -
negatively charged sulphates repel one=another to RESIST COMPRESSION, therefore, CUSHIONING

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3
Q

State where hyaline cartilage is found

A

Adults - Nose, respiratory tract, ribs, articular surface of bones

Fetus: in skeleton, before replaced by bone

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4
Q

Describe the structure of elastic cartilage

A

Amorphous matrix contains protein fibres

FIBRES: collagen, elastic fibre networks, therefore, this cartillage is more elastic than hyaline cartilahe

elastic fibres are ELASTIN

ELASTIN: elastic protein, provides flexibility + strength
FLEXIBLE BUT MAINTAINS SHAPE
YELLOW

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5
Q

Where is elastic cartilage found?

A

Externeal ear (pinna)
Walls of external auditory canal
Epiglottis
Larynx

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6
Q

Describe the structure of fibrocartilage

A

Amorphous matrix contains protein fibres
Fibres: collagen
COLLAGEN: resists tension / stretching

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7
Q

Why is fibrocartillage resistant to stretching?

A

Amorphous matrix conatins protein fibres

Protein fibres = collagen

Collagen arranged in bundles, all point in specific direction, therefore, resist stretching, compression, shearing (SLIDING / TEARING)
HIGH TENSILE STRENGTH
SHOCK ABSORBING

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8
Q

What is the most abundant type of cartillage?

A

Hyaline cartillage

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9
Q

State where fibrocartilage is found

A

Intervertebral disks
Menisci of knee

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10
Q

State the role of the perichondrium

A

Fibrous sheath surrounding cartilage except where cartilage merges
Contains blood vessels
BODY OF CARTILAGE IS AVASCULAR

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11
Q

Does fibrocartillage have a perichondrium layer? Explain your answer

A

No
Perichondrium is a sheath surrounding cartilage except from where it merges
Fibrocartilage merges into hyaline cartilage

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12
Q

What are the implications of cartilage being avascular?

A

Perichondrium contains blood vessels
Body of cartilage - avascular
NO BLOOD SUPPLY TO BODY OF CARTILAGE
AFFECTS FUNCTION, GROWTH, ABILITY TO HEAL

Limited ability to heal: NO DIRECT BLOOD SUPPLY, cells that repair cartilage, including chondrocytes, recieve nutrients and oxygen through diffusion from surrounding tissues rather than direct blood supply

Limited growth potential - lack of blood vessels = poor nutrient supply

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13
Q

Describe the blood supply of the cartilage

A

Supplied by blood vessels of:

  1. Perichondrium
  2. Synovial fluid
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14
Q

Describe the structure of fibrocartilage in the intervertabral disks

A

Annulus fibrosus - Layers of fibrocartilagein between the intervertebral disks in the spinal cord
Nuclues pulposus: Watery, (works like air in tire)
Intervertebral disks can resist lots of compression

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15
Q

Why can intervertebral disks resist a large amount of compression

A

-contain fibrocartilage
-in fibrocartilage, amorphous matrix conatins protein fibres
-fibres are collagen
-collagen provides tensile strength, resists tension / stretching - shock absorbing
-thereforee, resists compression
-the annulus fibrosus layer of fibrous cartilage in the intervertebrel disk
-nucleus pulposus - watery

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16
Q

State the 2 types of bones

A
  • compact
    -spongy
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17
Q

State the functions of bones

A
  • Support
    -Protection
    -Leverage
    -Storage of fats, minerals
    -Synthesis of blood cells (RBC, WBC)
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18
Q

Bone anatomy

A

Diagram L12

Cartilage
Epiphyseal line
Spongy bone
Compact bone
Bone marrow
Nutrient foramen
Nutrient vessel
Endosteum
Periosteum
Medullary cavity

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19
Q

State the 5 divisions of bones

A
  1. Long bones - humerus, femur, radius
  2. Short bones - carpals, tarsals
  3. Flat bones - sternum, cranium, scapula
  4. Irregular bones - vertebra, facial
  5. Sesamoid bones
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20
Q

What is the difference between sesamoid bones and other divisions of bones

A

Sesamoid do not share joints with other bones - they “float”
Examples include:
patella
hyoid bone of larynx

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21
Q

Describe the structure of a bone

A

DIAGRAM L12

Epiphysis - END
-spongy bone, red marrow
-compact bone, articular cartilage

Diaphysis - Middle
compact bone
medullary cavity contains yellow marrow (fat)
lined with endosteum (squammus epithelium)

Periosteum
membrane of connective tissue - covers enter outer surface of bone except epiphysis

Endosteum
-COVERS INERNAL BONE SURFACE
-THIN LAYER OF CONNECTIVE TISSUE
-OSTEOGENIC: contains osteoprogenitor cells

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22
Q

How is the periosteum attached to the bone?

A

Periosteum is secured to the bone via Sharpey’s fibres

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23
Q

State the 2 sublayers of the periosteum

A
  1. Outer fibrous layer
  2. Inner cellular osteogenic layer on compact bone (contains osteoprogenitor cells)
24
Q

Describe the structure of compact bone

A
  1. Osteocytes in spaces called lacunae, arranged in concentric circles - lamellae
  2. This suddounds central canal - complex is called Haversian system - THE OSTEON
  3. Canaliculi connect osteocytes to central canal + to each other
25
Q

State the role of osteocytes

A
  1. Detect mechanical stress
  2. Regulate BONE REMODELLING - via communicating with osteoblasts and osteoclasts
26
Q

What is the origin of osteocytes

A

Derived from OSTEOBLASTS during bone deposition

27
Q

How are osteocytes connected to one another?

A

GAP JUNCTIONS
(electrically connected via gap junctions, can transmit electrical signals to one another + to osteoblasts)

28
Q

State two differences between Osteoblasts and Osteoclasts

A

Osteoblast are uninucleate
Osteoclasts are multinucleate

Osteoblasts secrete bone matrix
Osteoclasts absorb bone matrix

29
Q

Where is spongy bone most commonly found?

A

Epiphyses

30
Q

Where is spongy bone only found? Why?

A

Epiphyses
Only found here because
-epiphyses subject to less mechanical stress than diaphysis
-epiphyses does not need same level of strength / support as diaphysis (shaft)
-helps to reduce weight of bone, making it easier for bone to move at the joint

31
Q

State the function of spongy bone

A

shock absorber

32
Q

State the stages involved in bone development

A
  1. Bone collar forms around hyaline cartilage model
  2. Cartilage in the centre of diaphysis calcifies and then develops cavities
  3. The periosteal bud invades the internal cavities and spongy bone begins to form
  4. The diaphysis elongates, medullary cavity forms as ossification continues.
    Secondary ossifcation centres appear in the epiphyses in prepation for stage 5
  5. The epiphyses ossify. When completed, hyaline cartilage remains only in epiphyseal plates + articular cartilages
33
Q

Explain the difference between development of bone in foetus and in children and young adults

A

In foetus - develops from hyaline cartilage
In children and young adults - Epiphyseal plate closure rate different by different locations
Can be used to estimate age
Bone reaches its peak density at around age 35

34
Q

Diagram of epipgyseal growth plates in child and adults

A

DIAGRAM L12

CHILD: LEFT
ADULTS: RIGHT

35
Q

State 3 types of joints

A
  1. Fibrous, surrounded by collagen fibres - NO MOVEMENT
  2. Sinovial, surrounded by sinovial fluid - LOTS OF MOVEMENT
  3. Cartilaginous, surrounded by cartikage - SOME MOVEMENT
36
Q

State the 3 types of fibrous joints

A
  1. Sutures
    FOUND ONLY IN SKULL
  2. Syndesmosis
    FOUND IN LIMBS
  3. Gomphosis
    HOLDS TOOTH IN SOCKET
37
Q

What type of joint is the pubic symphysis?

A

Cartilganious Joint

38
Q

State the location and functions of the pubic symphysis joint

A

4-5 mm gap Filled with FIBROCARTILAGE - strong connective tissue, flexible, allows small movement between two pubic bones
JOINS TWO PUBIC BONES AT FRONT OF PELVIS

39
Q

Describe what can happen to the pubic symphysis during pregnancy

A

gap filled with fibrocartilage increases
allows movement, flexivility during childbirth allowing pelvis to expand to allow passage of baby

joint can dislocate during rapid birth

40
Q

What is Pelvic Girlde Pain?

A

related to pubic symphysis
More common pregnant women
PAIN / DISCOMFORT in pelvic region
POST NATAL - AFTER BIRTH

41
Q

State the synovial joints

A

Plane joint - Intercarpal - between fingers

Hinge joint - elbow joint

Pivot joint - lower arm

Condyloid joint

Saddle joint - thumb

Ball-and-socket - SHOULDER

42
Q

Describe the composition of synovial fluid

A

Hyaluronic acid - hyaluronan
Lubricin- GLYCOPORTEIN

IT IS GOOPEY - VERY VISCOUS

43
Q

Where is lubricin produced?

A
  • Chondocytes
    -Synovial membrane cells
44
Q

Where is hyalaronic acid produced?

A
45
Q

What type of fluid is synovial fluid?

A

A non-newtonian fluid
Dilitant - DILATES - undergoes shear thickening

Viscocity increases with stress
making it a good shock absorber

46
Q

State the functions of Synovial fluid

A
  1. Lubrication
    of synovial joints
  2. Shock absorption
    in synovial joints - aided by cartilage / spongy bone
  3. Maintenane of cartilage
    Carries nutrients to chondrocytes in avascular cartilages+ + removes waste
47
Q

Why is synovial fluid a good shock absorber?

A

Non-newtonial fluid
Diltant - shear thickening with pressure
Viscocity increases with stress

48
Q

State an example of a newtonian fluid

A

WateraIR

49
Q

State causes of bone fractures

A

High force
High impact
High stress
Trivial injury as a result of certain medical conditions that weakens bones

50
Q

Give examples of bone fractures

A

PATHOLOGIC FRACTURES:

  • OSTEROPEROSIS
    OSTEOGENSIS IMPERFECTA
51
Q

Describe the process of bone remodelling

A
  1. Hemeatoma forms
  2. Fibrocartilaginous callus forms
  3. Bony callus forms
52
Q

Newtonian Fluid Calculation

A

Stress in fluid = viscocity x strain in fluid

Stress - force per unit of area - SHEAR STRESS
Strain - Deformation of fluid - SHEAR STRAIN

53
Q

Describe the characteristics of a newtonian fluid

A

As shear stress increases, shear strain also increases

As shear strain increases, viscocity stayes the same

Viscocity = constant at all strains / stresses

54
Q

What are the two types of non-newtonian fluids?

A
  1. Shear thinning
  2. Shear thickening
55
Q

Describe the characteristics of shear thinning non-newtonian fluids

A
  1. Stran increases non-linearly with stress
  2. Viscocity decreases with increasing strain / stress

BLOOD
PAINT

56
Q

Describe the characteristics of shear thickening Non-Newtonian Fluid

A
  1. Strain increases non-linearly with stress
  2. Viscocity increases with increasing strain / stress

SYNOVIAL FLUID (and other dilitants)