Unit 4 - Osseous Tissue and Bone Structure Flashcards
1
Q
How many bones does a normal human adult have?
A
206
2
Q
What is bone?
A
Rigid structure Dense connective tissue Variety of shapes and sizes Serves a variety of functions Active tissue
3
Q
What do ligaments attach?
A
Bone to bone
4
Q
What do tendons attach?
A
Muscle to bone
5
Q
7 functions of the skeleton
A
Support Protection Movement Electrolyte balance Acid-base balance Blood formation Metabolic functions
6
Q
What is matrix?
A
Calcium hydroxyapatite and organic collagen
7
Q
What makes the collagen fibers hard in bones?
A
When calcium and phosphorus comes together, they will precipitate on the collagen forming crystals. Those crystals harden and make the collagen fibers hard.
8
Q
7 general features of bones
A
Cortical bone Diaphysis Marrow cavity Epiphyses Cancellous bone Articular cartilage Nutrient foramina
9
Q
What are the 4 bone shapes?
A
Long bones
Short bones
Flat bones
Irregular bones
10
Q
2 features of long bones
A
Longer than wide
Rigid levers acted upon by muscles
11
Q
2 features of short bones
A
Equal in length and width
Glide across one another in multiple directions
12
Q
What do flat bones protect and what is their shape?
A
Protect soft organs
Curved but wide & thin
13
Q
7 structures of a long bone
A
Epiphyses Diaphysis Cortical Cancellous Marrow cavity Articular cartilage Periosteum
14
Q
2 structures of a flat bone
A
Two layers of cortical bone enclosing middle layer of cancellous bone
Diploe
15
Q
What is diploe?
A
Cancellous layer in cranium
16
Q
4 principal types of bone cells
A
Osteogenic cells
Osteoblasts
Osteocytes
Osteoclasts
17
Q
What are osteoblasts?
A
Bone forming cells
18
Q
What are osteocytes?
A
Mature osteoblasts trapped in matrix they deposit
19
Q
What are osteoclasts?
A
Cells that breakdown and reabsorb bone
20
Q
How do lacuna maintain the matrix?
A
It uses an osteocyte
21
Q
What is the function of canaliculi?
A
They carry nutrients to the bone cells
22
Q
How many bones are in the skull?
A
22
23
Q
What are 3 changes that affect bone?
A
Nutrition
Ratio of calcium to phosphate
Amount of trace minerals
24
Q
2 types of bone
A
Cortical
Cancellous
25
Which layer of bone is the hard, outer layer?
Cortical
26
Percentage of cortical bone in total bone mass of adult human skeleton
80%
27
What is cortical bone covered by on the outer and inner surfaces?
Periosteum on outer surface, and endosteum on inner surface
28
The basic structural unit of cortical bone
Osteon
29
What is the physical appearance of cancellous bone?
Sponge-like
30
Cancellous bone consists of? (3)
Spicules
Trabeculae
Red bone marrow
31
Which bone type is the interior of cortical bone?
Cancellous bone
32
Percentage of cancellous bone in total bone mass of adult human skeleton
20%
33
Description of cancellous bone
Thin formations of osteoblasts covered in endosteum
34
2 types of bone marrow
Red and yellow
35
What does hemopoietic tissue produce?
Blood cells
36
What is hemopoietic tissue composed of?
Multiple tissues
37
Which age group is yellow marrow found in?
Adults
38
What does most red marrow turn into?
Fatty yellow marrow
39
When does the skeletal system begin to develop?
6 weeks
40
What are the 2 ways bones are developed?
Intramembranous ossification
| Endochondral ossification
41
What happens during intramembranous ossification?
Bone is created by connective tissue
42
What happens during endochondral ossification?
Bone is created from cartilage
43
What types of bones does intramembranous ossification produce?
Flat bones of skull and clavicle
44
What does endochondral ossification start with?
The pre-existing cartilage model
45
During infancy and childhood, what do epiphyses fill with?
cancellous bone
46
by late teens to early twenties, what happens after all remaining cartilage in epiphyseal plate is consumed?
Gap between epiphyses and diaphysis closes
47
What happens to the bone when the gap between epiphyses and diaphysis closes?
The bone can no longer grow in length
48
What is osteogenesis?
Extracellular matrix laid down by osteoblasts
49
During osteogenesis, what do collagen fibers polymerize to form?
Collagen strands
50
4 cellular components of bone
Osteoblast
Osteoid
Osteocyte
Matrix
51
What are the 2 types of bone growth?
Bone elongation
| Appositional growth
52
Why is bone always turning over?
In response to calcium homeostasis
53
5 zones of metaphysis
```
Reserve cartilage
Proliferation
Hypertrophy
Calcification
Bone deposition
```
54
Where does bone grow in length?
The metaphysis
55
What is the term for bones growing in length?
Interstitial growth
56
What is the term for bones increasing in width?
Appositional growth
57
What % of bone remodeling occurs yearly?
10%
58
2 types of dwarfism
Achondroplastic
| Pituitary
59
Defining feature of achondroplastic dwarfism
Long bones stop growing in childhood
60
2 defining features of pituitary dwarfism
Lack of growth hormone
| Normal proportions with short stature
61
What occurs during mineralization?
Osteoblasts produce collagen fibers and fibers become encrusted with minerals that harden matrix
62
What are abnormal calcifications?
Calcifications that are irregular in size or shape or are tightly clustered together in an otherwise soft organ
63
Where is hydrogen pumped during mineral resorption?
The space between osteoclast and bone surface
64
Mineral resorption is performed by _____ at the ___ ___
Performed by osteoclasts at the “ruffled border”
65
What is calcium homeostasis?
The mechanism the body uses to maintain adequate calcium levels
66
How many grams of calcium in an adult human?
1100
67
Term for blood calcium deficiency
Hypocalcemia
68
Term for blood calcium excess
Hypercalcemia
69
What is a carpopedal spasm?
Hypocalcemia demonstrated by muscle spasm of hands and feet
70
Calcium homeostasis depends on the balance between...? (3)
Dietary intake, urinary and fecal losses, and exchanges between osseous tissue
71
Calcium homeostasis is regulated by three hormones:
Calcitriol
Calcitonin
Parathyroid hormone
72
What is calcitriol produced by? (3)
Skin, liver, kidneys
73
How does calcitriol raise blood calcium dioxide concentration? (3)
Increases calcium absorption by small intestine.
Increases calcium resorption from the skeleton.
Promotes kidney reabsorption of calcium ions.
74
What is calcitriol necessary for?
Forming new bones
75
What happens without an adequate amount of vitamin D?
An abnormal softness of bones
76
How does the body lower blood calcium concentration?
Calcitonin
77
2 ways calcitonin lowers blood calcium concentration
Osteoclast inhibition
| Osteoblast stimulation
78
How is calcitonin secreted?
By C cells in the thyroid gland
79
What secretes parathyroid hormone?
Parathyroid glands
80
Parathyroid hormones is released with...?
Low calcium blood levels
81
4 mechanisms parathyroid hormones use to raise calcium blood levels
1. Binds to receptors on osteoblasts
2. Promotes calcium reabsorption by the kidneys, less lost in urine
3. Promotes calcitriol synthesis in kidneys
4. Inhibits collagen synthesis by osteoblasts
82
When is bone growth rapid?
Puberty & adolescence
83
What do anabolic steroids do for growth?
Causes it to stop
84
What is a stress fracture?
Abnormal trauma to a bone
85
What is a pathological fracture?
Bone weakened by some other disease
86
What 3 characteristics are fractures classified by?
Direction of fracture line
Break in the skin
Multiple pieces
87
4 steps of fracture repair
1. Fracture hematoma formation
2. Callus formation
3. Cancellous bone formation
4. Cortical bone formation
88
Define osteoporosis
Bones lose mass and become brittle due to loss of organic matrix and minerals
89
Who is at the highest risk of osteoporosis?
Postmenopausal white women
