Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BL Sem 1 > Lecture 13 & 14 - Bone & Bone Marrow > Flashcards

Lecture 13 & 14 - Bone & Bone Marrow Flashcards

1
Q

What are some bone functions?

A
  • Protect important/delicate tissues
  • Hemopoiesis
  • Mineral storage (Ca and Phosphate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Desc. the structure of cancellous (spongy) and compact bone

A

Cancellous:

  • Network of fine bony columns (trabeculae)
  • Spaces filled w bone marrow
  • Osteocytes trapped within lacunae

Compact:
- Form external surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the types of ossification?

A
  • Endochondral ossification: Formation of long bones from cartilage at epiphyseal plates
    [appositional (at edges) growth]
  • Intra-membranous ossification: Formation of bone from mesenchymal stem cells in centre of cancellous bone (trabecular)
    [interstitial (middle) growth]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Desc. the bone formation in utero

A
  • Flat bone develops directly from mesenchymal tissue by intra-membranous ossification
    [Skull, jaw, scapula]
  • Long bones require cartilage template develop by endochondral ossification
    [femur, humerus]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Desc. intramembranous ossification in parietal (irregular bone of the skull) bone

A
  • Mineral deposits within trabeculae radiate outwards from a central point
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

State function of

  1. Osteoblasts
  2. Osteocyte
  3. Periosteum
  4. Osteo clasts
A
  1. Osteoblasts: Synthesise bone, lay down osteoid
  2. Osteocyte: Osteoblasts trapped in extracellular matrix. Canaliculi supply nutrients
  3. Periosteum: Attached to bone by collagen fibres known as Sharpey’s fibres. Outer layer contain fibroblasts, inner layer is MSC (diff. to form osteoblasts)
    [form most outer layer of bone]
  4. Osteoclasts: Resorption of bone –> initiate bone remodelling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How to identify osteoclasts?

A
  • Function is bone resorption

- Lie in a depression and has multiple nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does cancellous bone turn into cortical (dense) bone?

*X in ILO

A
  1. MSC converts into osteoblasts
  2. Lays down osteoid that is mineralised
  3. Osteoblasts gets trapped- osteocyte
  4. Form lamellae
  5. Central MSC turn into blood vessels, lymph vessels and nerves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the function of Volkmann’s canals?

A
  • Connect osteon to osteon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Diff. btw immature and mature bone is?

A
  • Immature bone osteocytes is in random arrangement, mature is arranged in lamellae of osteons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the starting points for bone remodelling?

A

Resorption canal (centre)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Diff of mature bone structure in compact and cancellous bone

A
  • Compact: Haversian canal (blood vessel, lymph vessel and nerves), Volkmann’s canal (osteon to osteon)
    [found in medullary /diaphysis region]
  • Spongy: No Harversian/Volkmann’s canals, osteoclasts at edge
    [found in epiphysis, edge]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where does bone strength come from?

A
  • Great tensile strength from cortical bone

lamellae are able to slip to resist fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the steps in bone remodelling (yellow slide) and what triggers it?

A
  • Steps:
    1. Osteoclasts make wide tunnel (cutting cone)
    2. Osteoblasts make small tunnel (closing cone)
  • Exercise stimulates bone remodelling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is osteoid?

A
  • Laid down by osteoblasts
  • Unmineralized bone (90% collagen, 10% ground substance)
    NOT BONE!!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the factors that affect bone stability?

A
  1. Activity of osteocytes:
    - Can act like osteoblasts and lay down osteoid in lacunae
    - Can act like osteoclasts and degrade bone (osteocytic osteolysis), ⬆️by PTH
  2. Activity of osteoblasts (main):
    - Stimulated by calcitonin (via IGF-1), oestrogen, testosterone, thyroid hormone, vit A
  3. Activity of osteoclasts (main):
    - ⬆️by PTH, release Ca2+ into bone
    - Calcitonin inhibit PTH at PTH receptor
  4. Nutrition:
    - Vit D3 produces calcitriol (calcium absorption)
    - Vit C: synthesis of collagen
    - Vit K and B12: synthesis of bone proteins
17
Q

What is osteogenesis imperfecta? Symptoms? Who does it usually affect?

A
  • Mutation in COL1A gene, autosomal dominant
  • Abnormal collagen 1 formed
  • Symptoms: short stature, weak bones (⬆️fracture), blue sclera
  • Mainly affects neonates and children
18
Q

What is rickets? Caused by what? Symptoms?

A
  • Mainly affects children
  • Vit D deficiency –> poor Ca mobilisation and ineffective mineralisation of collagen 1
  • Leads to weakened bone dev., short stature, waddling gait
19
Q

What is osteomalacia? Caused by what? Symptoms?

A
  • Rickets in adults
  • Vit D deficiency –> lower mineralisation and increase osteoids
  • Increased calcium resorption
  • Occurs in Vit D & Ca deficiency, women cover up skin, pregnant women, phenytoin (drugs) prevent vit D absorption
20
Q

What are the types of osteoporosis? Caused by what?

A

Primary:
Type 1
- Postmenopausal women (⬇️oestrogen –> ⬇️stimulation of osteoblasts to lay down osteoid, osteoclasts activity greater)
- Due to ⬆️osteoclasts
Type 2
- Older men and women
- Loss of osteoblast func (senile osteo.)
- Loss of oestrogen & androgen
- Incomplete filling of osteoclast resorption

Secondary:

  • Due to drug therapy (corticosteroids)
  • Due to malnutrition, prolonged immobilisation (affect bone remodelling)
  • Due to metabolic bone disease (hyperparathyroidism)
21
Q

Risk factors of osteoporosis are

A
  • Insufficient Ca intake (recommended 700mg/day)
  • Reduce exercise: maintain bone mass
  • Smoking
22
Q

What is achondroplasia? Results in what

A
  • Autosomal dominant inheritance in FGF3 (fibroblast growth factor) receptor gene
  • FGF promotes collagen formation from cartilage (endochondral ossification affected)
  • Results in short stature (normal size head & torso), long bones X lengthen properly
23
Q

Structure, example and function of long bones

A
  • Longer than wide
  • Eg: Femur, humerus, radius, tibia, metacarpal (hand), metatarsal (feet), phalanges (fingers n toes)
  • Located mostly appendicular skeleton
  • Func: Support weight of body & facilitate movement
24
Q

Structure, example and function of short bones

A
  • Length = width
  • Eg: Carpals & tarsals (wrist and ankle joints)
  • Provide stability & movement
25
Q

Structure, example and function of flat bones

A
  • Flattened
  • Eg: Skull (cranial bones), thoracic cage (sternum and ribs), pelvis, scapula
  • Protect internal organs, large area of attachment for muscles
26
Q

Structure, example and function of irregular bones

A
  • Vary in shape and structure
  • E.g vertebrae and sacrum (pelvis)
  • Protect internal organs, vertebrae protect spinal cord, provide anchor points for muscle
27
Q

Structure, example and function of sesamoid bones

A
  • Embedded in tendon
  • E.g patella (develop after birth, when start walking)
  • Protect tendon from stress and dmg (wear and tear)
28
Q

Desc 2 types of marrow in spongy bone

A

Red marrow:

  • Rich blood supply
  • Hemopoiesis

Yellow marrow:

  • Adipocytes (shock absorber, insulation, energy reserve, can convert to red marrow)
  • Poor blood supply
29
Q

How do maturing cells leave the bone?

A
  • Through sinusoids: endothelial cell fenestrations

- Platelets: megakaryocytes released fragments of cells through apocrine secretion directly into blood

30
Q

How is the flow in capillaries controlled? What function?

A
  • Controlled by precapillary sphincters

- Controls fluid exchange btw capillaries and body tissues, large cells X pass thru

31
Q

Define vein. Desc 3 layers and features

A
  • Vein: Transport blood from body tissue to heart
  • Tunica intima (endothelium), media (smooth muscle & elastic fibre), externa (elastic fibrous capsule)
  • Has fibroelastic cartilaginous valves
  • Pump blood under low pressure and against gravity
32
Q

Desc vein type

  1. Pulmonary
  2. Systemic
  3. Superficial
  4. Deep
A
  1. Oxygenated blood from lungs to left atrium
  2. De-oxy from body to right atrium
  3. Close to surface of skin
  4. Deep btw tissue

*venules smallest vein, inferior vena cava biggest

33
Q

Define artery. Desc 3 layers and features

A
  • Blood away from heart
  • Tunica intima (elastic membrane, non-fenestrated endothelium), media (thick smooth muscle, elastic fibres), adventitia/externa (collagen and elastic fibres: allow artery to stretch but prevents overexpansion)
  • Small lumen
34
Q

What are collateral blood vessels?

*sometimes referred to as communicating blood vessels

A
  • Arteries formed when there is blockage to provide alternative path for arterial blood
  • Generated due to ischaemia (reduced blood flow)
35
Q

What is structure and function of pericyte?

not in ILO

A

Structure:

  • Immature ‘smooth-muscle like’ cell
  • Key component of capillaries
  • Contractile properties
  • Blood-brain barrier

Function:

  • Differentiate into endothelial cell
  • Mantain tight capillaries
36
Q

How long does it take for RBC to mature upon entering general blood circulation?

A

1-2 days

37
Q

Where would osteoprogenitor cells usually be found?

A

In periosteum–> diff into osteoblasts at external surface

38
Q

What component of bone impedes distribution of nutrients to osteocytes?

A
  • Extracellular matrix

- Canaliculi supply

39
Q

Desc hypertension effect on each layer of artery/vein

A
  • Intima: artherosclerotic plaque formation, reduce lumen size
  • Media: hypertrophy of smooth muscle cell (become larger)
  • Externa: dmg extracellular matrix –> become larger/allow artery to stretch prevent over

BL Sem 1 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions