Bones Flashcards
What 2 categories can bones be divided into, based on location?
Axial
Appendicular
Define axial skeleton
Bones situated in the long axis of the body in anatomical position
Define appendicular skeleton
Bones that are appended to the axial skeleton, i.e. limbs.
Includes scapulae and pelvis
Which of the following bones belong to the axial skeleton and which appendicular?
Ribs
Vertebrae
Clavicle
Hip bone
Sacrum
Tibia
Ribs - axial
Vertebrae - axial
Clavicle - appendicular
Hip bone - appendicular
Sacrum - axial
Tibia - appendicular
What are the 2 functions of limb girdles?
Surround and support proximal ends of limb bones
Provide point of attachment for appendicular skeleton to axial skeleton
What 2 things is bone comprised of?
Collagen fibres
Impregnated by a crystalline calcium salt
Name the 2 types of bone
Compact (cortical) bone
Spongy (cancellous or trabecular) bone
What is found in the centre of bones and what’s the centre called?
Marrow (medullary) cavity
Name the 6 shapes of bone and give an example of each
Long - limb
Short - wrist
Flat - skull
Pneumatic - skull (air-filled cavity)
Sesamoid - patella
Irregular - vertebrae
What is the function of a sesamoid bone?
Relieve tension within muscles and tendons, allowing for increased weight-bearing and tolerance by redistributing forces throughout a muscle or tendon, thereby protecting them from significant strain and injury
Name the 3 parts of a long bone
Epiphysis
Diaphysis
Metaphysis
Define epiphysis
The epiphysis is the rounded end of a long bone, at its joint with adjacent bone(s)
Where is the epiphyseal plate?
Between the epiphysis and diaphysis
Define metaphysis
The wide portion of the long bones. This is commonly found between the two ends of a bone, meaning the epiphysis and the diaphysis
What is the metaphysis part of?
The metaphysis is part of the growth plate. It develops during childhood, its ossification centres being located close to the ends of the bone
The metaphysis contains a highly metabolic set of tissues including what 3 things?
Trabecular bone
Blood vessels
Marrow Adipose Tissue
Condyle vs Epicondyle: What is their shape? What size are they? What do they articulate with?
Condyles are usually more rounded
Condyles are smooth and large; epicondyles are rough and small
Condyles articulate with bone; epicondyles provide a surface for muscle and ligament attachment
Compact bone is composed of a ____ and surrounded on the outside by a ____ and on the inside by a _____
Compact bone is composed of a HAVERSIAN SYSTEM and surrounded on the outside by a PERIOSTEUM and on the inside by a ENDOSTEUM
Which osteogenic cells are found in the periosteum?
Osteoblasts
Where specifically are osteoblasts found?
Periosteum
In what part of a long bone is compact bone mainly found?
The diaphysis
In what part of a long bone is spongy bone found?
Epiphysis
In what part of long bone is bone marrow found?
Inside the diaphysis
What are the 2 colours and functions of bone marrow?
Red and yellow
Red makes blood cells
Yellow stores fat
What is an increase in bone width called?
Appositional growth
“Appositional” means to add (appose) new bone tissue from the outside (from the periosteum) onto the existing bone.
What is an increase in bone length called?
Interstitial growth
“Interstitial” means growth occurring through cell division in the epiphyseal growth plate, i.e., within the existing bone
Does the periosteum or epiphyseal plate give rise to appositional bone growth?
Periosteum leads to appositional growth
Does the periosteum or epiphyseal plate give rise to interstitial bone growth?
Epiphyseal plate gives rise to interstitial bone growth
Which bone cells are active in fracture-healing process?
Osteocytes
What cells make bones and what break them down?
Osteoblasts and osteoclasts
Which one of the following bones belongs to the appendicular skeleton?
Ribs
Cervical vertebrae
Sacrum
Xiphoid bone
Hip bones
Hip bones
Compact bone is:
a. trabecular in architecture
b. synthesised by osteoclasts
c. resorbed by osteoblasts
d. arranged circumferentially
e. found in the marrow cavity
arranged circumferentially
What type of bone is the patella?
Sesamoid
When osteoclasts break down bone, they form a reabsorption pit. What’s it called?
Howship’s lacuna
Haversian canals run vertically along the bone. What canal runs horizontally, connecting Haversian canals?
Volkmann’s Canal
What membrane covers the outside of bones? What membrane covers the inside of bones?
Periosteum
Endosteum
What 3 things is ECM made of?
Hydroxyapatite crystals, collagen (Type I) and water
In terms of resorption and formation of bone, what is:
Osteoporosis
Paget’s disease
Osteopetrosis
Osteoporosis = more resorption than formation
Paget’s disease = more resorption and formation
Osteopetrosis = less resorption
What causes brittle bone disease?
A deficiency of Type 1 collagen
Why does menopause lead to a steep decline of bone mass in women?
Oestrogen has an inhibitory effect on osteoclasts
Less oestrogen = osteoclasts remove more bone
Name the 2 types of ossification
Endochondral
Intramembranous
Explain endochondral ossification
Bone forms as cartilage “model” first
BVs invade cartilage
Cartilage replaced by bone
Cartilage remains in epiphyseal growth plate
Growth plate eventually ossifies
Explain intramembranous ossification
Mesenchymal cells develop into osteoprogenitor cells that mature into osteoblasts
Residual mesenchymal cells develop BVs and bone marrow
Which type of ossification can occur in adult bone?
Intramembranous ossification
What cells develop into osteoprogenitor cells?
Mesenchymal cells
Name the 2 types of bone growth (the way they grow larger)
Appositional growth
Interstitial growth
Define and differentiate between woven bone and lamellar bone
The first bone formed at any site is woven (or primary) bone, but this is soon replaced by lamellar bone. In woven bone the collagen fibres are random. In lamellar bone, the collagen fibres have become re-modelled to become more parallel - in layers.
