Chapter 11 Flashcards
1
Q
What are bones?
A
-rigid, mineralized structures
2
Q
What are the functions of bones?
A
- Support
- Protection
- Movement
- Mineral Storage! -Calcium and Phosphorus
- Hematopoiesis! -Blood formation
3
Q
What type of bone tissue is there?
A
- Cancellous (Trabeculae)
- Compact
4
Q
What types of bone shapes are there?
A
- long
- short
- flat
- irregular
- sesamoid
5
Q
What are examples of long bones?
A
- Femur
- Humerus
6
Q
What are examples of short bones?
A
- Carpal
- Tarsal
7
Q
What are examples of flat bones?
A
- Scapula
- Ribs
- Sternum
8
Q
What are examples of irregular bones?
A
- Vertebrae
- Facial
9
Q
What are examples of sesamoid bones?
A
-Kneecap
10
Q
What components make up a long bone?
A
- Diaphysis: long, hollow shaft
- Epiphysis: knobs containing spongey bone
- Articular cartilage: thin layer of hyaline cartilage that covers joint surfaces
- Periosteum: outer dense covering of a bone that is not on joint surfaces; fuses to muscle fibers
- medullary cavity: marrow is stored here; hollow part of the diaphysis
- endosteum: lines the inside of the bone
11
Q
What components make up a flat bone?
A
- Internal table: internal compact bone
- external table: external compact bone
- diploë: inner spongey bone
- periosteum: outer dense covering of a bone that is not on joint surfaces; fuses to muscle fibers
- endosteum: contain red marrow
12
Q
What is bone tissue? What is it made of?
A
- Osseous tissue
- Made of connective tissue
- Extracellular matrix
13
Q
What is the extracellular matrix composed of?
A
- Water: 25%
- Collagen: 25%
- Crystallized calcium phosphate: 50%
14
Q
What is calcification? Performed by?
A
- depositing calcium phosphate to make a bone
- made by osteoblasts
15
Q
What is the basic unit of dense bone?
A
- osteons
- Haversion system
16
Q
What do osteons do?
A
- surround a central canal
- permit delivery of nutrients
- remove waste from bone cells
17
Q
What are the osteons composed of? Describe and Function
A
- Lamellae: round layers
- Lacunae: small spaces in bone matrix
- Canaliculi: the cracks; canals that get nutrients from blood vessels to osteocytes
- Central canal: middle hole; contains blood vessels, lymphatic vessels, and nerves
- Transverse canal: connect central canals
18
Q
What is cancellous bone made out of?
A
-Crisscrossing trabeculae
19
Q
Where do you find cancellous bone?
A
-On the inside of the bone in the epiphyses
20
Q
What does the cancellous bone contain?
A
-red bone marrow
21
Q
What are the types of bone cells? Functions
A
- osteogenic stem cells: undergo mitosis to become osteoblasts (only one with mitosis)
- osteoclasts: breaks down bone to regulate blood calcium level
- osteoblasts: builds bones and adds calcium to bone (eventually becomes an osteocyte)
- osteocytes: exchange nutrients and wastes with the blood (forms when osteoblast becomes embedded in bone matrix)
22
Q
What does red bone marrow do?
A
-produces red and white blood cells
23
Q
Where do you find bone marrow?
A
-medullary cavity
24
Q
Where do you find red bone marrow in infants?
A
-every bone
25
Where do you find red bone marrow in adults?
- ribs
- vertebrae
- ends of humerus
- pelvis
- femur
- sternum
26
What is yellow bone marrow made of?
-adipocytes
27
What does yellow bone marrow do?
-convert to red bone marrow in times of decreased blood supply
28
Why does the blood calcium level matter?
- nerve and muscle cells depends on calcium ions to function
- clotting requires calcium
- many enzymes require calcium as as a cofactor
29
What is the blood calcium level controlled by?
- parathyroid hormone
| - calcitonin
30
What does the parathyroid hormone do?
- released when calcium levels are too low
| - stimulates osteoclasts which releases calcium into the blood
31
What is the pathway for homeostasis when it comes to parathyroid hormone?
- Below normal calcium levels
- parathyroid hormone released
- osteoclasts are stimulated
- release of calcium into blood
32
What secretes parathyroid hormone?
-parathyroid gland
33
What does calcitonin do?
- is released when calcium level is too high
- stimulates the osteoblasts and stores extra calcium
- inhibits osteoclasts
34
What is the pathway for homeostasis when it comes to calcitonin?
- High blood calcium
- stimulates osteoblasts, inhibits osteoclasts
- calcium will move into the bones
- removal of calcium from blood
35
What secretes calcitonin?
-thyroid gland
36
What is ossification?
-the process by which bones form
37
What situations are involved in development of bone?
- formation in embryo
- growth
- remodeling
- fracture healing
38
What is intramembranous ossification?
-development of the ossification center
39
-Where does intramembranous ossification occur?
- flat bone of the skull
| - mandible
40
How does intramembranous ossification occur?
- soft spots in the skull become ossified
- calcification
- formation of trabeculae
- development of the periosteum
41
How does the ossification center form?
-group of osteoblasts that secrete matrix
42
What cells help with ossification?
-osteoblasts secrete matrix and eventually become inclosed and become an osteocyte
43
What is endochondral ossification?
-bone formation spreads from the center to the ends
44
Where does endochondral ossification occur?
-most of the bones
45
How does endochondral ossification occur?
- Develop a hyaline cartilage (chondroblasts) model of bone; surrounded by perichondrium (connective tissue)
- Perichondrium develops into the periosteum at the diaphysis; osteoblasts from periosteum deposit bone; cartilage begins to calcify
- Blood vessels enter the midpoint of the diaphysis; “primary ossification center”
- Bone growth proceeds from the diaphysis toward each epiphysis; medullary cavity is developed
- Secondary ossification centers appear in the epiphysis; epiphyseal plate
- Ossification of the cartilage occurs nearest the diaphysis (allows bone growth)
46
How do bones grow in length?
- growth of cartilage at the epiphyseal plate
| - replacement of cartilage by bone tissue
47
What is bone remodeling?
-bone continually renews itself
48
What happens if there is too much bone?
-bones become too thick and heavy
49
What happens if there is too little bone?
- weak bones
| - osteoporosis
50
What happens if bone is too flexible?
- too much collagen and not enough calcium
- rickets
- osteomalacia
51
What factors influence bone remodeling and how?
- the balance of osteoblasts and osteoclasts
- minerals
- vitamins
- hormones
52
What do each of the vitamins do?
- vitamin A: stimulates osteoblasts
- vitamin C: synthesis of collagen
- vitamin D: helps build bone; increases the absorption of calcium
- vitamin K and B12: needed for synthesis of bone proteins
53
What are the hormones needed to affect bone growth?
- growth hormone: produced by pituitary gland
- thyroid hormone: promotes bone growth by stimulating osteoblasts
- insulin: promotes bone growth by increasing the synthesis of bone proteins
- estrogen and testosterone: growth spurt
- parathyroid hormone
- calcitonin
54
What are the different kinds of fractures?
- compound: bone protrudes through skin
- simple: does not break the skin
- comminuted: splintered, crushed, many pieces
- greenstick: one side is broken the other side bends
- impacted: one end of the fractured bone is forcefully driven into another
- Pott's: fibula breaks with injury of the tibial articulation
- Colles': fracture to radius in which the distal fragment is displaced
- stress: microscopic fissures in the bone
55
What is the process of healing a fracture?
- fracture hematoma: blood clotting on both sides
- procallus: islands of cartilaginous tissue; bridges broken ends
- bony callus: binds the broken ends
- remodeling
56
How is fracture repair initiated?
-initiated by bone death
57
What do fracture hematomas contain?
- inflammatory cells
- fibroblasts
- osteoblasts
- chondroblasts
- new capillaries
58
Describe cartilage.
- collagen fibers form in gel
- avascular
- chondrocytes
59
Describe bone.
- collagen fibers in calcified cement substance
- very vascular
- osteoclasts, osteoblasts, and osteocytes
60
Describe the similarities between bone and cartilage.
- many collagen fibers
| - cells lie in lacunae
61
What is the perichondrium?
- fibrous covering of the cartilage that contains blood vessels
- gives cartilage nutrients by diffusion
62
What types of cartilage are there? Characteristics?
- hyaline: most common; contains collagen fibers
- elastic: contains elastic and collagen fibers
- fibrocartilage: has the most collagen; greatest strength but not flexible
63
Where can you find each type of cartilage?
- hyaline: covers articular surfaces of bone; costal cartilage; cartilage rings of trachea, bronchi, and nose
- elastic: ear, epiglottis, Eustachian (auditory) tubes
- fibrocartilage: in pubic symphysis and intervertebral discs
64
What is the function of cartilage?
- withstands great weight
- shock-absorber between bones
- strong and pliable support structure
- permits growth in long bones
65
How does cartilage grow?
- appositional growth: chondrocytes in the deep layer of the perichondrium divide and secrete matrix
- interstitial growth: cartilage cells within the cartilage divide and secrete additional matrix; childhood and early adolescence
66
How does exercise and aging affect bone tissue?
- the more exercise, the stronger the bone becomes
| - age can cause: decrease bone mass by bone resorption
67
What are the two principle effects of agin on bone tissue?
- loss of bone mass caused by loss of calcium
| - brittleness caused by decreased rate of protein synthesis (collagen)
68
What are the three different lamellae?
- Concentric: cylinder shaped; part of osteon
- Interstitial: layers between osteons
- Circumferential: runs along the circumference of the osteons
