LEC 9/10 Flashcards
THE SKELETAL SYSTEM (77 cards)
1
Q
Skeletal system designed for: (3)
A
- Support
- Protection
- Movement
2
Q
System is made up of ______ types of connective tissue
A
3
3
Q
Types of connective tissue in skeletal system
A
Cartilage
Ligaments
Bones
4
Q
Cartilage
A
specialized connective tissue
5
Q
Ligaments
A
dense fibrous connective tissue
6
Q
Bones
A
hard elements of the skeleton
7
Q
Cartilage is made of: (3)
A
- fibers of collagen
- elastic tissue
both embedded in ground substance
8
Q
Cartilage is ________ and more flexible than ______
A
- smoother
- bones
9
Q
Cartilage is found where
A
support under pressure is important (along with some movement)
10
Q
Cartilage ________ friction in joints
A
reduces
11
Q
Types of Cartilage (3)
A
- Fibrocartilage
- Hyaline Cartilage
- Elastic Cartilage
12
Q
Fibrocartilage (Where?) (What?)
A
Collagen fibers arranged in thick bundles
Found between vertebral discs & menisci in knees
13
Q
Hyaline cartilage (Made up of?) (Where?) (What?)
A
Glassy cartilage made of thin collagen fibers
Precursor to bones
Found at the ends of mature bones
14
Q
Elastic cartilage (Made up of?) (Where?) (What?)
A
Made of elastin fibers
Highly flexible
Found in ear & epiglottis
15
Q
Ligaments attach ______ to _________
A
- bone
- bone
16
Q
What do ligaments do?
A
Provide strength to joints while still allowing movement of bones in relation to each other
17
Q
Ligaments are made up of
A
dense fibrous connective tissue (mostly collagen fibers)
18
Q
Ligament fibers are all orientated in the ______ direction.
A
same
19
Q
Bones consists of: (4)
A
- Non-living extracellular crystals of calcium minerals
- Living bone cells
- Nerves
- Blood vessels
20
Q
Functions of bones (5)
A
- Support
- Movement
- Protection
- Blood cell formation
- Mineral storage
21
Q
Humans have _____ bones
A
206
22
Q
Types of bones (4)
A
- Long
- Short
- Flat
- Irregular
23
Q
Long Bones (def + example)
A
longer than they are wide
Examples: femur, humerous, ulna, radius
24
Q
Short Bones (def + example)
A
small and cube like
Examples: bones of the wrist
25
Flat Bones (def + example)
very thin in one dimension
Example: ribs
26
Irregular Bones (def + example)
Odd shapes
Example: vertebrae
27
Diaphysis (3)
1. Cylindrical shaft of long bone
2. Covered with compact bone
3. Contains yellow bone marrow
28
Compact bone
dense, hard, smooth outer part of a bone
29
Epiphysis (4)
1. Knobs at each end of long bone
2. Covered with compact bone
3. Has spongy bone inside
4. Filled with red bone marrow and stem cells
30
Outer surface of long bone is covered with tough layer of connective tissue
periosteum
31
The periosteum has specialized bone forming cells called
osteocytes
32
Osteocytes
specialized bone forming cells
33
Osteons
Arranged in rings in cylindrical structures
34
Haversian canal
Nutrients received via central canal
35
Cells become enclosed by _______ ________ as the bone develops and becomes _____
1. calcium phosphate
2. hard
36
Lacunae
Hollow chambers in bone that house osteocytes
37
Individual cells remain in contact with each other through thin canals called
Canaliculi
38
Nutrients are exchanged between osteocytes through
gap junctions
39
The basic structural units of compact bone
osteons
40
Canaliculi allow osteocytes to: (2)
1. Communicate
2, Exchange nutrients and waste products, and signals
41
Osteocytes summary (6 main terms)
1. Bone is arranged in cylindrical structures called OSTEONS.
2. Nutrients and waste are transported in each osteon through a central canal called the HAVERSIAN CANAL.
3. As the bone forms, it becomes hard because of CALCIUM PHOSPHATE.
4. Osteocytes, are trapped in small chambers called LACUNAE.
5. Osteocytes are connected to each other by tiny channels called CANALICULI.
6. Nutrients are exchanged between osteocytes through GAP JUNCTIONS.
42
Embryo bone development
Chondroblasts produce hyaline cartilage, which creates the framework for future bones like SCAFFOLDING
43
Chondroblasts
produce hyaline cartilage during embryo bone development
44
Fetal bone development (2-3 months)
1. Periosteum and blood vessels begin to develop
2. Cartilage dissolves & is replaced by bone material through OSSIFICATION
45
Ossification
1. Chondroblasts die and the matrix they produced breaks down inside shaft of future bone
2. Blood carries OSTEOBLASTS to the site
46
Osteoblast Activity Steps (6)
1. Secrete osteoids
2. Secrete enzymes that help the production of
hydroxyapatite
3. Eventually osteoblasts become embedded in hardening bone tissue
4. Osteoblast activity declines. 5. They become mature osteocytes embedded in their own lacunae (space) within the matrix
6. Mature osteocytes continue to maintain the bone matrix
47
Osteoids
A mixture of proteins
48
Purpose of osteoids
1. Forms the internal structure of bone
2. Provides strength to bone
49
hydroxyapatite
mineral component (mainly calcium phosphate) that gives bones their strength and rigidity
50
Bone development for childhood to adolescence
1. Bone growth is controlled by growth hormone and sex hormones.
2. The EPIPHESEAL PLATE is present at the ends of long bones.
3. On the OUTside of the EPIPHESEAL PLATE, chondroblasts (cartilage cells) continue making new cartilage.
4. On the INside of the EPIPHESEAL PLATE, the cartilage is turned into bone.
5. As new bone is added, the bone lengthens, and the two epiphyseal plates move apart, allowing bones to grow longer.
51
Epipheseal plate
growth plate at each epiphysis
52
on the OUTside of the EPIPHESEAL PLATE,
chondroblasts (cartilage cells) continue making new cartilage.
53
On the INside of the EPIPHESEAL PLATE
the cartilage is turned into bone
54
Bone remodeling
Process of removing mature bone (resorption) and creating new bone to replace it
55
Bone remodeling done in response to :
calcium levels in the blood and mechanical stress
56
Osteoclasts are
Specialized cells that act as “bone breaking” cells
57
Osteoclasts process (2)
1. Secrete enzymes that dissolve the hydroxyapatite and digest the osteoid matrix
2. Calcium & phosphate ions enter blood
58
During bone remodelling, new osteoblasts are attracted to the area so they can: (2)
Stimulate the deposition of new hydroxyapatite crystals and osteoid matrixes
59
_______ ________ _______ increase overall bone mass and _______
1. Weight bearing exercises
2. strength
60
Bone Replacement:
continuous process where old bone is replaced by new bone.
61
Bone is ________ in areas of high ___________ stress and removed or resorbed in areas of _______ compressive stress
1. created
2. compressive
3. low
62
“Remodeled bone” matches the _________ of __________ forces it is exposed to
1. distribution
2. compressive
63
The bone changes _____ and ______ based on the ______ it experiences.
1. shape
2. size
3. stresses
64
areas under _______ compressive stress (like where the bone bears weight) will have _____ bone created, while areas under _____ stress will have bone ________.
1. high
2. more
3. low
4. removed
65
4 types of bone cells
1. Chondroblasts
2. Osteoblasts
3. Osteocytes
4. Osteoclasts
66
Chondroblasts
hyaline cartilage forming cells that build the model of the future bone
67
Osteoblasts (3)
1. bone-forming cells
2. Produce the osteoid and help make hydroxyapatite
3. Become trapped in the bone and mature into osteocytes
68
Osteocytes
1. mature bone cells
2. that maintain the structure of bones
69
Osteoclasts
bone dissolving cells
70
Osteoblast and osteoclast activity is regulated by __________
hormones
71
Hormones function to maintain ________ levels at “homeostasis” for bone growth
calcium
72
Bone growth: Two hormones work in opposition to one another
Calcitonin
Parathyroid Hormone
73
Calcitonin secreted from and when?
thyroid gland when blood calcium levels rise above a given point
74
Bringing calcium to homeostasis steps (4)
1. Blood calcium levels rise above normal, the thyroid releases calcitonin.
2. Calcitonin stimulates osteoblasts to add more calcium and phosphorus into the bones, helping lower blood calcium levels.
3. It also inhibits osteoclasts , which prevents the release of calcium into the blood.
4. Calcitonin reduces calcium absorption in the small intestine and reduces calcium reabsorption in the kidneys, encouraging excess calcium to be excreted in urine.
75
Parathyroid Hormone secreted when and where?
parathyroid gland when blood levels of calcium fall below a given point
76
PTH steps (2)
1. Stimulates osteoclasts, releasing calcium and phosphate into the bloodstream to raise blood calcium levels.
2. Increases calcium and magnesium absorption in the kidneys and boosts the production of vitamin D. Vitamin D helps the small intestine absorb more calcium.
77
Over time, if PTH levels remain _______, it can lead to bone ____________ & __________
1. high
2. demineralization
3. osteoporosis
