Week 1: Functions of the Skeletal System Flashcards
How much calcium, on average, is found within the skeletal system?
99%
Calvaria
Top of the skull / upper part of neurocranium.
What does the Calvaria cover?
The cranial cavity containing the brain.
What bones are the Calvaria made of?
i.e. frontal, temporal, occipital, parietal, Ethmoid, Sphenoid
Frontal,
Occipital,
Parietal.
List two main structural frameworks that protect internal organs.
Calvaria for the brain,
Thorax for the lungs and heart.
Hemopoiesis
Production of blood cells and platelets, which occurs in red bone marrow.
Do Juveniles or Adults have more red marrow within their Trabecular bone?
Juveniles
Do Juveniles or Adults have more yellow marrow within their Trabecular bone?
Adults - yellow bone marrow consists of triglycerides.
Main 4 functions of the Skeletal System.
Structural framework,
Support,
Muscle attachment points to allow for movement of antagonistic pairs.
Approximate % water in the extracellular matrix?
15%
Approximate % collagen fibres in the extracellular matrix?
30%
What type of material are collagen fibres considered to be in the extracellular matrix? (i.e. organic / inorganic)
Organic
What cells secrete collagen into the extracellular matrix?
Osteoblasts
What is the meaning of the suffix -blast in “osteoblast”?
Secretion
Why is collagen secreted into the extracellular matrix?
To prevent against tensile pressures that would normally shatter/break bones.
For flexibility.
Approximate % crystallised mineral salts in the extracellular matrix?
55%
Hydroxyapatite
crystallised inorganic mineral salts.
Cells in Osseous Tissue of bones? Name the 4 types.
Osteogenic Cells,
Osteoblasts,
Osteocytes,
Osteoclasts.
What are Osteogenic cells also known as?
Osteoprogenitor stem cells.
What do Osteogenic cells/Osteoprogenitor stem cells differentiate into?
Osteoblasts.
Where are Osteogenic cells/Osteoprogenitor stem cells found in bone?
Outer surfaces of bone (within the inner cellular layer of the periosteum), and in the medullary cavity (endosteum and lining the Haversion canals).
Function of Osteoblasts?
Secretes collagen to build the extracellular matrix, which will ossify/calcify to create harder bone.
What remains when osteoblasts finish building the extracellular matrix?
Osteocytes (mature bone cells)
Function of Osteocytes?
Osteocyte processes to other osteocyte processes (projections) communication - cell to cell communication - for upkeep of metabolism in bone tissue.
Suffix meaning of Osteoclasts?
“-clast” meaning resorption/breakdown.
Function of Osteoclasts?
Breakdown of older bone tissue to allow for the creation of new bone tissue.
Function of the “ruffled border” of osteoclasts?
Ruffled border = highly infolded plasma membrane edge.
Secretion of lysosomal enzymes.
High acid content due to breakdown of bone.
Order of presence in bone tissue of: osteoblasts, osteocytes, osteogenic cells/osteoprogenitor stem cells.
- Osteogenic cells/osteoprogenitor stem cells (same thing): differentiates into osteoblasts).
- Osteoblasts: forms bone extracellular matrix.
- Osteocytes: maintains bone tissue (metabolism).
How are osteoclasts formed?
coagulation of monocytes.
Compact bone AKA? (2 other names)
Cortical bone, Dense bone
Cortical bone AKA? (2 other names)
Compact bone, Dense bone
Dense bone AKA? (2 other names)
Compact bone, Cortical bone
Spongy bone AKA? (2 other names)
Trabecular bone, Cancellous bone
Trabecular bone AKA? (2 other names)
Spongy bone, Cancellous bone
Cancellous bone AKA? (2 other names)
Spongy bone, Trabecular bone
Compact/Dense/Cortical bone: strength.
More solid, bend-resistant
Location of Compact/Dense/Cortical bone
Forms external layer of all bones & bulk of diaphysis.
Weight of Compact/Dense/Cortical bone
Heavier due to higher density than trabecular bone.
Spongy/Trabecular/Cancellous bone: strength.
Strength for compression. Present at joints - predominantly trabecular bone with a cortical bone layer.
Location of Spongy/Trabecular/Cancellous bone
Forms the majority of short bones (i.e. carpals), flat bones (i.e. calvaria - skull), irregular bones (i.e. vertebrate / spinal column), ends of long bones).
Structure/Description of Spongy/Trabecular/Cancellous bone.
Contains larger spaces - reduces the overall bone weight, protects yellow and red bone.
Abundance of Spongy/Trabecular/Cancellous bone?
More abundant, lighter weight allows movement.
Abundance of Compact/Dense/Cortical bone.
Less abundant, heavier.
Diaphyses AKA?
Shaft
Location of diaphyses?
Main/mid-section of long bone.
Diaphyses structure?
Made of cortical bone and contains bone marrow and adipose tissue (fat).
Components of Compact/Cortical bone. What is an osteon also referred to as, and what is consisted within it?
Osteons = Haversian Systems. Concentric Lamellae (ringed portion), Central Canal (Haversian canal), Lacunae (latin: lake), Canaliculi (extensions of lacunae), Interstitial Lamellae, Perforating/Volkmann's canals, Circumferential lamellae.
How are Osteons organised?
Haversian Systems (AKA Osteons): Aligned in the same direction along lines of stress to the bone, Well organised, Dynamic structural units - formation of new osteons and breakdown of old.
Description of Concentric lamellae (incl. function).
Ringed portion of a cross-section of bone,
circular plates of mineralised/calcified extracellular matrix,
they fit within one another to make an osteon.
Structural and Function of central canal (Haversian canal)
Passageway for neurovasculature & lymphatics,
Contains blood vessels, nerves and lymph channels.
Structure and Function of Lacunae (latin: lake)
Small spaces between concentric lamellae,
Osteocytes sit within lacunae.