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Anatomy and Physiology > Chap5: The Skeletal System > Flashcards

Chap5: The Skeletal System Flashcards

0
Q

Components of skeletal system

A

Bones
Cartilage
Joints
Ligaments

Living tissues capable of

  • growth
  • adaptation to stress
  • auto repair after injury
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1
Q

Definition of skeletal system

A

It’s the structural framework that:

  • gives the body its shape
  • provide protection for internal organs and soft tissues
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2
Q

The skeletal system provides:

A

Support

Protection

Allows body mvt

Stores minerals and fats

Site of blood cell production

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3
Q

Functions of skeletal system

A

Support:

  • rigid strong bone –> bare weight
  • major supporting tissue of body

Protection:
Bone is hard –> protects surrounding organs

Mvt:
Skeletal muscles attach to bones via tendons (strong bands of connective tissues)

Storage:
Minerals in blood are taken into bone and stored
Minerals: calcium, phosphorus, fat (adipose tissue)

Blood cell production:
Cavities filled with red bone marrow (blood cells + platelets)

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4
Q

Number of bones in body

A

Average adult skeleton: 206 bones

But # decreases as person ages (bones fuse)

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5
Q

Division of bones of skeleton

A

Axial skeleton

  • skull
  • vertebral column
  • rib cage

Appendicular skeleton

  • bones of upper and lower limbs
  • girdles/coxal (attach appendicular bones to axial)
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6
Q

Basic types of bone tissue

A

Compact bone: homogenous

Spongy bone: small needle like structure + has many open spaces

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7
Q

Classification of individual bones

A

According to shape:

Long (eg femur, humerus)

  • longer than wide
  • long shaft + 2 ends
  • contain mostly compact bone

Short (eg carpals, tarsals)
-cube shaped

Flat (eg skull bones, sternum, scapulae, ribs)

  • thin and flattened
  • curved
  • thin layer of compact bone around layer of spongy

Irregular (vertebrae, coxae)

  • complicated shape
  • don’t fit in any other class
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8
Q

Components of growing long bone

A

Diaphysis / shaft
-composed mostly of compact bone –> mostlybone matrix + small few spaces)

Epiphysis (end of bone)

  • composed mostly of spongy bone –> mostly small spaces surrounded by bone matrix
  • outer surface: layer of compact bone
  • joints covered by cartilage

Epiphyseal plate

  • hyaline cartilage
  • where growth in bone length occurs –> after growth it becomes ossified: epiphyseal line (transformation from cartilage to bone)

From upper to lower:
Proximal epiphysis –> epiphyseal line/plate –> diaphysis –> line/plate –> distal epiphysis

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9
Q

Diaphysis of long bone

A

Medullary cavity= large space filled with marrow
-red marrow–> site of blood cell formation
(All kid bones filled with red marrow)
-yellow marrow–> adipose tissue
(In adults skull and limbs filled with yellow marrow
EXPT their proximal epiphysis)

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10
Q

Periosteum

A

Def: connective tissue membrane that covers outer surface of bone

Divided into 2 layers:

Outer fibrous layer

  • dense irregular collagenous ct
  • contains blood vessels (supply bone with nutrients)
  • nerves

Inner layer
-single layer of bone cells (osteoblasts, osteoclasts, osteochondral progenitor)

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11
Q

Sharpey’s fibers

A

Secure periosteum to underlying bone

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12
Q

Articular cartilage

A

Covers external surface of epiphysis

Made of hyaline cartilage

Decreases friction at joint surfaces

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13
Q

Hard and flexible bone composition

A

Osteochondral progenitor cells –> osteoblasts –> osteocytes (bone cells)

Lacunae = cavities in matrix where osteocytes found

Lamellae= concentric circles of lacunae

Harvesian central canal = centers of lamella
Carry blood vessels and nerves

Canaliculi = tiny canals carrying nutrients from central canals to lacunae

Volkmann’s perforating canals = provide communication between layers and center of bone (perpendicular)

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14
Q

Organic components of bone and fct

A

Comp:

  • osteocytes
  • osteoclasts
  • osteid (ground substance and collagen fibers)

Fct:
Contribute to flexibility and tensile strength of bone

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15
Q

Inorganic components and fct

A

Comp: make up 65% of bone by mass
-mineral salts –> calcium phosphate

Fct:
Hardness and compression resistance of bone

16
Q

Bone formation and remodeling

A

Skeleton formed from strongest and most supportive tissues of body

  • cartilage
  • bone
In embryos: 
Skeleton primarily made of hyaline cartilage --> replaced by bone
But cartilage remains in isolated areas:
-bridge of nose
-parts of ribs
-joints
17
Q

Ossification

A

Def: dev of bones using hyaline cartilage as their model
(Except for flat bones –> form on fibrous membranes)

Steps:

  • hyaline cartilage completely covered with bone matrix by osteoblasts
  • hyaline cartilage digested away–> medullary cavity
18
Q

Intramembranous ossification

A

From week 4 to year 2

In flat bones
Starts with collagen fibers –> connective tissue

-Mesenchymal cells (ct, fibers)
-Osteochondral progenitor
-Osteoblast –> osteocyte
=> ossification center (filling fontanelles)

19
Q

Endochondral ossification definition

A

Week 5 to 18-20 years

For the rest of the bones
Starts from cartilage

-Mesenchymal cells
-Chondroblast –> chondrocyte
=> produces hyaline cartilage surrounded by perichondrium (former periosteum)

20
Q

Endochondral ossification steps

-primary ossification center in diaphysis

A

Mesenchymal cells –> chondroblasts –> chondrocytes

Chondrocytes produce cartilage surrounded by perichondrium
Perichondrium contains osteoclasts + osteoblasts (produced via osteochondral progenitor)

Blood vessels invasions of perichondrium
Chondrocytes enlarge + accumulate Ca –> forming calcified cartilage

Blood vessels invade cartilage + bring from perichondrium: osteochondral progenitor, osteoblast, osteoblast
Osteoblast: add bone matrix + form bone (start spongy –> compact)
Osteoclast: digest calcified cartilage in the middle –> medullary cavity
+more blood vessels enter

=> primary ossification center in diaphysis

21
Q

Endochondral ossification steps

-secondary ossification center in epiphysis

A
  • Calcified cartilage
  • Invasion of blood vessels
  • No transformation to compact + no cavity –> stays spongy
22
Q

Most hyaline cartilage have been converted to bone except for 2 regions

A

Articular cartilage

  • covers bone ends
  • persist for life
  • reduce friction at joint surface

Epiphyseal plate
-provide longitudinal growth of long bone during childhood

23
Q

How do bone widen?

A

Osteoblast in periosteum
-add bone tissue to external face of diaphysis
Osteoclast in endosteum
-remove bone from inner face of diaphysis wall

Process in which bones increase in diameter = appositional growth

24
Q

Bone formation and remodeling control?

A

By growth hormones (secretion during night increases)
+ by sex hormones during puberty

Ends when epiphyseal plate completely converted to bone (becomes line)

25
Q

Bones remodeled continually in response to changes in 2 factors

A

Bone dynamic and active tissue –> always modifying

Factors:
Ca levels in blood
-if Ca level drops -> parathyroid glands release PTH ( parathyroid hormones) -> activates Osteoclast to break down bone matrix + release Ca ions into blood (+ uptake in kidneys and intestins increases)
-if Ca level too high –> hypercalcemia Ca deposited in. One matrix as hard Ca salt

Pull of gravity and muscles of skeleton
-bulky thick muscle -> thicker bone with large projections
(Osteoblast deposit new matrix and become mature bone cells)
-bones lose mass + atrophy if physically inactive

PTH to see if need more/less Ca
Stress of muscles to see where bone matrix is to be formed/broken down

26
Q

Types of bone fractures

A

Closed/simple fracture = bone breaks cleanly without penetrating skin

Open/compound fracture = bone ends penetrate through skin

27
Q

How fracture treated

A

Treated by reduction = realignment of broken bone ends
After that, bone immobilized by cast or traction

Healing time is 6 to 8 weeks
(But longer for bigger bones or elderly)

28
Q

Fracture type

A

Comminuted = bone breaks into many fragments

Compression = bone is crushed

Depressed = pressed inward

Impacted = crushed/forced into each other

Spiral = twisting force

Green stick = breaks incompletely

29
Q

4 major events for repair of bone fractures

A

Hematoma formation

  • blood vessels ruptured
  • blood filling swelling forms (hematoma)
  • > bone cells deprived of nutrition die

Break splinted by fibrocartilage callus

  • macrophage, osteoclast clean area
  • osteochondral progenitor -> Chondroblast (form cartilage) + osteoblast => induce bone matrix formation and deposition (endo)

Bony callus formed

  • more osteoblast and osteoclast migrate and multiply
  • fibrocartilage replaced by bony callus (spongy bone)

Bony callus remodeled

  • forms permanent patch
  • collagen deposition
30
Q

Factors affecting bone growth

A

Potential shape and final height determined genetically
But factors can modify expression of genetic factors

Nutrition (deficiency -> stop growth before ep plate) 
Minerals: 
-Ca
-phosphorus
-magnesium (osteoblast)
-boron (no Ca loss)
-manganese (new matrix)

Vitamins
-D: increase intestinal absorption of Ca + retards Ca urine loss
Deficiency causes rickets (kids bone inflammation) and osteomalacia
-C:

Anatomy and Physiology (3 decks)

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