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Flashcards in Lecture 3 Deck (49)
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1
Q

Types of cartilage (3)

A
  1. Hyaline
  2. Elastic
  3. Fibrocartilages
2
Q

Perichondrium

A

Surrounds cartilages
Resists outward pressure (adds strength)
Functions in growth and repair

3
Q

Cartilage

A

Connective tissue
Consists primarily of water
Resilient tissue: can return to original form

4
Q

Chondrocyte

A

Cartilage cell type

Exists inside lacunae

5
Q

Lacunae

A

Cavity within cartilage matrix

House chondrocytes

6
Q

Cartilage matrix

A

Contains fibers and jellylike ground substance

7
Q

Hyaline cartilage

A
"glass": translucent
Most abundant
Chondrocytes appear spherical
Collagen fibers in matrix
Ground substance holds large amount of water
Provides support through flexibility
8
Q

Elastic cartilage

A

Contains many elastic fibers
Yellowish in colour
Able to tolerate repeated bending
Located in epiglottis and external ear

9
Q

Fibrocartilage

A

No perichondrium
Resists strong compression and strong tension
Intermediate between hyaline and elastic
Located in pubis symphysis, mensici of knee, annulus fibrosus

10
Q

Growth of cartilage (2)

A
  1. Appositional growth
  2. Interstitial growth
    Cartilage stops growing when the skeleton stops growing
11
Q

Functions of bones (5)

A
  1. Support/protection
  2. Movement
  3. Mineral storage
  4. Blood formation
  5. Energy metabolism (osteoblasts secrete osteocalcin)
12
Q

Osteocalcin

A

Secreted by osteoclasts

Thought to due with body homeostasis

13
Q

Bone tissue make up (2)

A
  1. 35% organic components

2. 65% inorganic components

14
Q

Organic components

A

Cells, fibers, ground substance

Contribute to flexibility and tensile strength

15
Q

Inorganic components

A

Mineral salts that invade bony matrix

Provide exceptional hardness, resist compress

16
Q

Cells that produce or maintain bone (3)

A
  1. Osteogenic cells
  2. Osteoblasts
  3. Osteocytes
17
Q

Osteogenic cells

A

Stem cells that differentiate into osteoblasts

18
Q

Osteoblasts

A

Actively produce and secrete bone matrix

19
Q

Osteoid

A

Bone matrix

20
Q

Osteocytes

A

Keep bone matrix healthy

21
Q

Osteoclasts

A

Found within bone tissue
Crawls along bone surface
Giant cell with many nuclei
Responsible for reabsorption of bone
Derived from line of hematopoietic stem cell
Secrete hydrochloric acid and lysosomal enzymes

22
Q

Compact bone

A
Dense outer layer
Contains passage ways for blood vessels, lymph vessels and nerves
Osteons
Osteocytes sandwiched between lamellae
Volkmann's canals
23
Q

Spongy bone

A

Cancellous
INternal network of bone
Trabeculae: little beams of bone
Open spaces between trabeculae are filled with marrow

24
Q

Endosteum

A

Inner lining inside bone

25
Q

Epiphyses

A

Ends of long bone

26
Q

Bone design and stress

A

Anatomy of bone reflects stresses
Compression and tension are greatest at external surfaces
Centre of bone does not have any force

27
Q

Structure of typical long bone (5)

A
  1. Diaphysis: shaft
  2. Epiphyses - ends of bone
  3. Blood vessels
  4. Medullary cavity
  5. Membranes
28
Q

Diaphysis

A

Shaft of long bone

29
Q

Medullary cavity

A

Hollow cavity filled with yellow marrow

30
Q

Membranes of long bone (3)

A
  1. Periosteum
  2. Perforating collagen fiber bundles (Sharpey’s fibers)
  3. Endosteum
31
Q

Diploe

A

Internal spongy bone of flat bones

32
Q

Osteons

A

Present in compact bone
Contain lamellae, central canal, perforating canals and canaliculi
Long cylindrical structures
Function in support
Structurally resemble rings of a tree in cross section

33
Q

Volkmann’s canals

A

Perforating canals

Allow passage of nutrients and cell communications between Haversian systems

34
Q

Ossification/osteogenesis

A

Bone formation

35
Q

Intramembranous ossification

A

Membrane bones

Formed directly from mesenchyme

36
Q

Endochondral ossification

A

All bones except some bones of skull and clavicles
Bones are modeled in hyaline cartlage
Begins forming late in the second month of embryonic development
Continues forming until early adulthood

37
Q

Ephiphyseal plates

A

Cartilage organized for quick, efficient growth
Cartilage cells form tall stacks
Chondroblasts at top of stacks divide quickly
Pushes epiphysis away from piaphysis
Lengthens entire long bone

38
Q

Older chondrocytes

A

Bone elongation
Signal surrounding matrix to calcify
Die and disintegrate, leaving long trabeculae of calcified cartilage on diaphysis side
Trabeculae are partly eroded by osteoclasts, which are then covered by bone tissue by osteoblasts
Trabeculae are eaten away from their tips by osteoclasts

39
Q

Postnatal growth of endochondral bones

A

During childhood and adolescence
Bones lengthen entirely by growth of epiphyseal plates
Cartilage is replaced with bone connective tissue as quickly as it grows
Epiphyseal plate maintains constant thickness
Whole bone lengthens

40
Q

Hormonal regulation of bone growth (3)

A
  1. Growth hormone
  2. Thyroid hormone
  3. Sex hormones
41
Q

Growth hormone

A

Produced by the pituitary gland

Stimulates epiphyseal plates

42
Q

Thyroid hormone

A

Ensures that the skeleton retains proper proportions

43
Q

Sex hormones

A

Estrogen and progesterone
Promote bone growth
Lated induces closure of epiphyseal plates

44
Q

Bone remodelling

A

Bone is dynamic living tissue
500mg of Ca may leave or enter skeleton each day
Bone matrix + osteocytes are continually removed by reabsorption and replaced by bone deposition by osteoblasts
Cancellous bone is replaced every 3-4 years, compact bone is replaced every 10 years

45
Q

Osteoporosis

A

Characterized by low bone mass
Bone reabsportion outpaces bone deposition
Occurs most often in women after menopause

46
Q

Osteomalacia

A

Occurs in adults

Bones are inadequately mineralized

47
Q

Rickets

A

Occurs in children

Analogous to osteomalacia

48
Q

Osteosarcoma

A

Form of bone cancer

49
Q

Skeleton throughout life

A

Stops growing from 18-21

Bone mass declines with age