Unit 2: Skeletal System Flashcards by Amy Groshan

Functions of Skeletal System

Support
Protection
Movement
Blood formation
Mineral Reservoir
pH balance

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Describe the mineral deposition process

-Minerals removed from blood plasma
-Minerals deposited in bone tissue
-Fibroblasts deposit collagen fibers along osteons
-Osteoblasts encrust the fibers with minerals

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Define osteogenic tissue

Beginning of bone cells found in connective tissue, go through mitosis to create osteoblasts

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Define osteoblast cell

Bone-producing cell which mineralizes organic matter of the matrix

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Define osteocyte cell
Describe the significance of lacunae and canaliculi

Osteoblast cell trapped in a mineralized, tough matrix
Osteocytes are found in lacunae in the bone, which are connected by canaliculi so that they can communicate with eachothers and with osteoblasts/osteoclasts

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Define lacunae

A “cave” in the bone where osteocytes reside

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Define canaliculi

Passage between lacunae “caves” where osteocytes can send signals to other osseous cells

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Define osteoclast cell
(where they come from, purpose, location)

Form of white blood cell which develops from fused stem cells
Lowers the pH to degrade bone tissue
Reside in resorption bays

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Main 3 minerals found in bone tissue

Phosphate, Calcium, Bicarbonate

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Purpose of phosphate

Component in DNA, RNA, ATP, and phospholipids

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Purpose of Calcium

Needed for communication between neurons, muscle contractions, blood clotting, exocytosis, and more

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Purpose of Bicarbonate

Regulates pH of bodily fluids

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The ECM of bone is what portion organic and what portion inorganic?

1/3 organic
2/3 inorganic

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What is the organic matter in osseous tissue?

Collagen, glycosaminoglycans, proteoglycans, glycoproteins

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What is the inorganic matter in osseous tissue?

85% hydroxyapatite
10% calcium carbonate
Fluoride, sulfate, potassium, magnesium

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What is hydroxyapatite?

Crystallized calcium phosphate salt

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Why is bone a combination of organic and inorganic matter?

Minerals give the bone strength to resist compression
Collagen gives the bone resilience to resist tension

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What are the 3 hormones which regulate calcium homeostasis?

Calcitriol, Calcitonin, Parathyroid

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What is Calcitriol?
How is it produced?
What is its function?

Vitamin D, blood borne messenger hormone

Produced by UV radiation on skin or digestion which is processed by kidney or liver

Helps intestine absorb calcium, phosphate, magnesium more
Promotes urinary resorption of calcium
Promotes osteoclast acitivty
Boosts calcium levels in blood

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What is Calcitonin?
How is it produced?
What is its function?

Hormones secreted by C cells in thyroid gland

Is released when calcium levels in blood are too high

Reduces osteoclast activity
Increases osteoblast # and acitivity

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What is Parathyroid?
How is it produced?
What is its function?

Hormones secreted by parathyroid gland

Is released when calcium level in blood are too low

Increases osteoclast activity
Increases calcium reabsorption and calcitriol synthesis
Decreases osteoblast activity

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Describe the process of mineral resorption

Osteoclasts dissolve bone to release minerals into the blood
High acidity in space between osteoclast and bone dissolves tissue

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Bones are ______ tissue

Connective

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The 2 structures of bones are

Compact and spongey

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Where is red bone marrow found?

Spongey bone

The shapes of bones are

Long Short Flat Irregular

Describe long bone shape Example of a long bone:

Longer than wide with expanded ends Humerus, radius, ulna

Describe short bone shape Example of a short bone:

Equal length and height Carpals, tarsals

Describe flat bone shape Example of flat bone:

Platelike Ribs, frontal, parietal

Describe irregular bone shape Example of irregular bone:

Wide variety of shapes Vertebrae, coccyx, sphenoid, ethmoid

Define epiphysis

Enlarged ends of a long bone Spongey bone covered with articular cartilage and some compact bone

Define diaphysis

Shaft of a long bone covered in periosteum Compact bone with a marrow cavity (medullary cavity) lined with endosteum

Define periosteum

Outer surface of bone

Define endosteum

Inner lining of medullary cavity

Define medullary cavity

Cavity within long bone where yellow bone marrow is found, is lined with endosteum

Define epiphyseal plate/line

Epiphyseal plate (children) / line (adults) is where epiphysis meets diaphysis on a long bone

Describe the appearance of flat bones

Covered exteriorly and interiorly by compact bone Spongey middle layer, but no medullary cavity

Compact bones are made of

Osteons

Define osteon

"Bricks" Cylinders of tissue that form layers of matrix (lamellae) arranged around central canal

Define lamellae

Layers of matrix

The central canal holds

Blood vessels

Osteocytes are connected to eachother and the blood supply through

Canaliculi

Define perforating canals

Canals which run perpendicularly to connect central canals

Spongey bone is made of

Trabeculae

Define trabeculae

Rods and plates of bone with spaces filled with red bone marrow

Trabeculae always form along

Stress lines

Red bone marrow is located in

Trabeculae in spongey bone

Yellow bone marrow is located in

Medullary cavity of long bones, contain fatty adipose marrow

Intramembranous ossification produces _____ bones found where

Flat Skull and clavicle

Endochondral ossification produces bone from

A cartilage model

Define stress fracture

Break caused by abnormal trauma to bone

Define pathological fracture

Break caused by weakness of bone due to disease

Bone usually heal in ________ weeks

8-12 weeks

Name the stages of bone repair:

Hematoma Granulation tissue Callus formation Remodeling

Describe the Hematoma step of bone repair

Broken blood vessels form a clot

Describe the Granulation tissue step of bone repair

Fibrous tissue formed by fibroblasts are infiltrated by capillaries

Describe the Callus formation step of bone repair

Soft callus of fibrocartilage forms, is replaced by hard callus on bone in 6 weeks

Describe the Remodeling step of bone repair

Bone "overgrows" so over the next 6 month, spongey bone is replaced by compact bone

Describe Osteoporosis and its risk factors

Bone loses mass and becomes brittle (most common) Risk Groups: Lower estrogen (menopause) Lack of calcium and protein Lack of Vitamin D Lack of weight-bearing exercise Smoking

Describe Rickets and its risk factors

Lack of Vitamin D results in softness of bones in children (bowlegged) Risk Groups: Dietary Restrictions (lactose intolerant, vegan) Celiac disease Dark skin Lack of sun Can be genetic

Describe Osteomalacia and its risk factors

Lack of Vitamin D results in muscle and bone pain in adults Risk Groups: Lack of sun Lack of Vitamin D in diet Celiac disease Medications for seizures Gastric Surgery Kidney/Liver disease

Describe Osteogenesis Imperfecta and its risk groups

"Brittle Bone Disease," - inability to produce collagen Bones fracture easily, hearing loss, and blue tint to sclera Risk Groups: Autosomal dominant genetic disease Congenital (born with it)

What hormone activates when you need more calcium in your bloodstream?

Parathyroid

What hormone activates when you need less calcium in your bloodstream?

Calcitonin

Define hypercalcemia and its effects

Too much calcium in blood stream, can cause coma and death

Define hypocalcemia and its effects

Not enough calcium in blood stream, can cause muscle spasms and seizures

What process creates flat bones and how?

Intramembranous Ossification Creates osteoblasts cells from connective tissue, which gather on trabeculae. Calcium phosphate is deposited onto the matrix and creates osteocytes. Marrow spaces are made in the center of bone (spongey) and hardened compact bone forms on the outside periosteum.

What process creates bones other than flat bones?

Endochondral ossification Uses cartilage model to form bones. The cartilage model contains chondrocytes in center which create primary ossification center. Bony collar is made and chondrocytes die leaving a marrow cavity. Osteoblasts calcify on the trabeculae.

Where are the osteogenic layers of bone?

Periosteum

What different connective tissues make up the skeletal system?

Bones, cartilage, tendons, ligaments

What is the function of canaliculi in compact bone?

Supply nutrients via blood vessels, remove cellular wastes, and channels for communication between osteocyte