Lecture Exam 3 Flashcards
1
Q
Functions of bone
A
- Structure and support
- Protection
- Stores minerals (calcium)
- Important for blood cell development
2
Q
What forms of calcium are important for making bone?
A
- Calcium phosphate
2. Calcium hydroxide
3
Q
Hydroxyapatite
A
Calcium phosphate and calcium hydroxide formed together; a crystal that makes bones hard
4
Q
2/3 of bone is made up of what
A
Calcium phosphate
5
Q
1/3 of bone is made up of what
A
Collagen, which gives out bones some flexibility
6
Q
Rickets
A
A disease of calcium deficiency that causes bones to bend, especially in legs
7
Q
What is the importance of vitamin D
A
It helps us absorb calcium
8
Q
Osteogenesis Imperfecta
A
A disease of collagen deficiency, causes brittle bones
9
Q
Diaphysis
A
The shaft of a long bone
10
Q
Epiphysis
A
The end of the shaft
11
Q
Metaphysis
A
Where bones grow longer; where the diaphysis connects to the epiphysis
12
Q
Types of bones that make up a long bone
A
- Compact bone
2. Spongy bone
13
Q
Compact bone
A
Dense, solid bone; extremely strong in one plane; surrounds the diaphysis for protection
14
Q
Medullary cavity
A
The hollow space of the diaphysis; Bone marrow
15
Q
Osteon
A
Makes up compact bone; the entire circular structure
16
Q
Central canal
A
In compact bone; has blood vessels (usually an artery and a vein); brings in nutrients and takes away waste products
17
Q
Concentric lamellae
A
In compact bone; each circle that makes up an osteon
18
Q
Osteocyte
A
In compact bone; The dark spots in a concentric lamellae that makes bone until it traps itself in a lacuna
19
Q
Lacuna
A
Compact bone; Where the osteocytes trap themselves
20
Q
Canaliculi
A
Compact bone; Tunnels that connects all of the osteocytes together; made by osteocytes to get nutrients from the central canal
21
Q
Interstitial lamellae
A
Compact bone; Bone tissue that fills in the gaps between the osteons; made from old osteons that have been recycled
22
Q
Circumferential lamellae
A
Compact bone; Allows bones to grow in diameter; surrounds an osteon completely; created from stress on the bone and makes the bone bigger
23
Q
Periosteum
A
Compact bone; A layer of connective tissue that surrounds the bone; allows tissue to connect to bone
24
Q
Perforating fibers
A
Compact bone; Collagen fibers that embeds in the bone and prevents the periosteum from pulling away when the muscles pull on it; originates in periosteum
25
Spongy bone
Surrounds the epiphyses; strong in multiple planes
26
Trabeculae
Fibers that make the web-like structure of the osteons in spongy bone
27
Types of cells in bones
1. Osteoprogenitor cells
2. Osteoblasts
3. Osterocyte
4. Osteoclast
28
Osteoprogenitor cell
Comes from mesenchymal stem cell; stem cell that can only become bone cells; divide and helps make and repair bone
29
Mesenchymal stem cell
A stem cell that has the ability to form many types of cells
30
Osteoblasts
Osteoprogenitor cells mature/form into this; bone forming cell
31
How osteoblasts create bone
1. Osteoblasts create osteoid
| 2. Osteoblasts raise calcium above its solubility limit
32
Osteoid
The foundation of bone; the organic part of bone; this is where collagen is found
33
Solubility limit
When sugar is continually added to water and won't dissolve anymore; calcium does this and crystalizes, making bones strong and hard
34
When is a osteoblast called an osteocyte
Once an osteoblast makes all the calcium that is can and is trapped in a lacuna
35
FOP
Osteocytes are overactive and osteoblasts are formed in tissue where they should not be
36
Osteoclasts
Formed from a macrophage; this cell type degrades/breaks down bone
37
How do osteoclasts and osteoblasts work
They work together in equilibrium
38
When does bone growth begin
At 6 weeks post fertilization
39
How do bones begin
They begin as cartilage until osstification
40
Osstification
The process of replacing other tissues with bone
41
Two forms of osstification:
1. Endochondral osstification
| 2. Intramembranous osstification
42
Endochondral osstification
The formation of long bones
43
Intramembranous osstification
The formation of non long bones
44
Chondrocytes
Cells that make hyaline cartilage
45
Cartilage is what kind of tissue
Avascular tissue
46
Why is cartilage avascular?
Because chondrocytes make anti-angiogenesis factor
47
Anti-angiogenesis factor
Made by chondrocytes that prevents blood vessel formation
48
Hypertrophy
When chondrocytes swell and get large; shortly after undergoing hypertrophy the chondrocytes die which enables blood vessel growth
49
Where does bone formation begin?
At the diaphysis (shaft)
50
What happens once blood vessels grow
Nutients and bone cells (mesenchymal stem cells that become osteoblasts and macrophages that become osteoclasts) begin to be delivered into the center of the cartilage
51
How is cartilage turned into bone?
1. Osteoblasts turn all of the cartilage into bone
| 2. Osteoclasts carve out the medulla to make bone hollow
52
Primary osstification center
The place in the diaphysis that is osstified first
53
Secondary ostification center
The place in the epiphysis that is osstified after the primary
54
What is different about the secondary osstification center from the primary osstification center?
Not all of the cartilage is osstified and turned into bone
55
Examples of cartilage that is not turned into bone
1. Articular cartilage
| 2. Epiphysis cartilage
56
Articular cartilage
Cartilage that surrounds the end of the epiphysis; this reduces friction between bones
57
Epiphyseal cartilage
This is between the diaphysis and the epiphysis; this is the "growth plate" where bones can grow longer; once it is gone, the bone cannot get any longer
58
How is intramembranous ossification different from endochondral ossification?
Flat bones do not start off as cartilage
59
How are flat bones made?
Osteocytes make bone, then osteoclasts carve out the bone and make it into a specific shape
60
Types of post-developmental bone growth
1. Appositional growth
| 2. Epiphyseal growth
61
Appositional growth
Increase in bone diameter
62
Epiphyseal growth
Increase in bone length
63
Where does appositional growth happen and how does it happen?
At the circumferential lamellae, osteoblasts add more circumferential lamellae layers
64
What is different about appositional growth and epiphyseal growth?
Appositional growth occurs throughout your lifetime, epiphyseal growth begins at birth and lasts throughout the end of puberty
65
What causes an increase in appositional growth
Stress on a bone
66
What happens on the lower part (B) of the epiphyseal cartilage?
Osteoblast turns cartilage into bone
67
What happens on the upper part (A) of the epiphyseal cartilage?
Chondrocytes make new cartilage, as fast (almost) as the osteocytes are making bone
68
Hormones that are important during puberty
1. Testosterone
2. Estrogen
3. Growth hormone (HGH)
69
What makes growth hormone
The pituitary gland
70
What happens to these hormones during puberty
They increase a lot
71
What do hormones do during puberty?
They make osteoblasts and chondrocytes work faster
72
Why do osteocytes work a little faster than chondrocytes?
So that eventually the epiphyseal cartilage gets smaller and puberty stops
73
Epiphyseal line
Shows where the epiphyseal cartilage was after puberty
74
How much calcium is in bones?
99%
75
Where is the other 1% of calcium?
In the blood
76
What is normal blood calcium level
8.5-11mg/dL
77
Parathyroid gland
Regulates blood calcium level
78
Parathyroid cells
Secrete parathyroid hormone
79
What does the parathyroid hormone do?
It targets
1. Bone
2. Intestines/Digestive system
3. Kidneys
80
How does the parathyroid hormone effect bone?
It increases osteoclasts and inhibits osteoblasts
81
How does the parathyroid hormone effect intestines/digestive system?
It increases calcium absorption from food which increases blood calcium levels
82
How does the parathyroid hormone effect kidneys?
It increases calcium absorption in the kidneys so that we don't lose calcium in the urine
83
How do all of the effects of the parathyroid hormone work together?
They all happen at the same time
84
Types of bones
1. Long bones
2. Short bones
3. Sesamoid bones
4. Flat bones
5. Sutural bone
6. Irregular bone
85
Example of long bone
Humerus
86
Example of short bone
Carpals
87
Sesamoid bones
Bone that forms inside of a tendon
88
Example of sesamoid bones
Patella
89
Example of flat bone
Ribs and sternum
90
Sutural bone
Found within the sutures of the skull
91
Example of irregular bone
Vertebrae
92
Articulations
Where two bones interconnect
93
Synarthroses
Immoveable joints
94
Amphiarthroses
Slightly moveable joints
95
Diarthroses or Synovial
Freely moveable joints
96
Types of synarthroses joints
1. Suture
2. Gomphosis
3. Synchondrosis
4. Synostosis
97
Suture
Skull bones bound together by dense connective tissue
98
Gomphosis
Teeth bound to bony sockets by periodontal ligaments
99
Synchondrosis
Two bones bound by rigid cartilaginous
100
Example of synchondrosis
Joints in hand before fusing
101
Synostosis
Two bones completely fused
102
Example of synostosis
Joints in hand after fusing
103
Why don’t the sutures form until after birth?
1. To get through the birth canal
| 2. The brain expands and gets bigger
104
Types of amphiarthroses joints
1. Syndesmosis
| 2. Symphasis
105
Syndesmosis
Bones connected by collagenous fibers
106
Example of syndesmosis
Distal and proximal tibiofibular joints
107
Symphasis
Bone separated by fibrocartilage
108
Example of symphasis
Pubic symphasis
109
Example of diarthroses
Shoulder, knees
110
Synovial membrane
A membrane that surrounds the diarthroses
111
Synovial fluid
Inside the membrane between the joints
112
What is the purpose of synovial membrane and fluid?
Reduces friction and creates a large range of motion
113
Function of skeletal muscle
1. Gives us voluntary movement
2. Generates body heat
3. Stores nutrients (Glycogen)
114
Epimysium
In skeletal muscle; connective tissue that surrounds the muscle; separates each muscle
115
Perimysium
In skeletal muscle; Where all blood supply and nerves are found; separates the muscle fascicle
116
Muscle fascicle
In skeletal muscle; one bundle of fibers
117
Muscle fibers
In skeletal muscle; composes the inside of a muscle fascicle
118
Endomysium
In skeletal muscle; connective tissue that separates muscle fibers in a muscle fascicle
119
Characteristics of muscle cells
1. Long and cylindrical
2. Many nuclei found on the plasma membrane
3. Striated
120
Sarcolemma
The plasma membrane of a muscle cell/fiber; generates and propagates action potentials
121
Transverse or T tubules
Tunnels that lead to the middle of the cell; allows an action potential to move from the membrane to deep into the cell
122
Sarcoplasmic reticular
The ER of the muscle cell/fiber; makes proteins; stores and releases calcium
123
Myofibril
Makes up a muscle fiber/cell
124
Sarcomere
Makes up myofibril that contains proteins
125
Protein lines in the sarcomere
1. M line
2. Z line
3. Thick filaments
4. Thin filaments
126
M line
In the middle of the sarcomere
127
Z line
There are two; one on each end of the sarcomere
128
Thick filaments
Attaches to the M line and extends towards the Z line
129
Thin filaments
Attaches to the Z lines and points towards the M line
130
Zone of overlap
Where the thick and thin filaments overlap
131
Sliding filament theory
In order for a contraction to occur, thin filaments must slide along the thick filaments towards the M line
132
Myosin
The only protein that makes up thick filaments
133
Parts of a myosin
1. Myosin tail
2. Myosin head
3. Hinge
134
Characteristics of the myosin head
1. Responsible for contacting thin filament
2. Forms the cross bridge
3. Can power stroke
4. Requires ATP
135
Power stroke
Describes the movement of the myosin head; always pulls the thin filaments towards the M line
136
Hinge
Connects the head to the tail and allows movement
137
Proteins that make thin filaments
1. G-actin
2. Tropomyosin
3. Troponin
138
G-actin
Has an active site
139
F-actin
Made of many G-actin
140
Active site
Where the myosin head contacts the thin filaments and creates a cross bridge
141
Tropomyosin
Blocks the active site
142
Troponin
Moves the tropomyosin to unblock the active site
143
Things troponin interacts with/touches
1. G-actin
2. Tropomyosin
3. Calcium
144
Troponin will only pull tropomyosin off G-actin if there is what
Calcium
145
Neuromuscular junction
A motor neuron forms a synapse with a muscle cell
146
Cholinergic
Describes a neuron that secretes Acetylcholine
147
Steps in initiating a muscle contraction
1. Acetylcholine (Ach) is released from the synapse and binds to receptors
2. Action potential (Ach) reaches a T tubule to bring it deep into the cell
3. Action potential reaches the sacroplasmic reticulum and it releases calcium (Ca2+)
148
The contraction cycle
1. Calcium arrives
2. Calcium binds to troponin and exposes the active site
3. The myosin head forms a cross bridge with an active site
4. The myosin head power strokes
5. ATP is required to break the cross bridge and reset
149
How do we control tension within a single sarcomere?
1. Controlling the starting length of the sarcomere
| 2. Controlling the frequency of stimulation
150
When is maximum tension produced?
When the zone of overlap is large but the thin filaments do not extend across the sarcomere's center; all of the myosin heads can make a cross bridge
151
What makes something the optimal starting length
1. The zone of overlap is long, making you able to make the most cross bridges
2. Having enough room for the thin filaments to slide between the thick filaments
152
As the sarcomere length gets longer
There are less cross bridges that can be made (smaller zone of overlap)
153
What prevents the sarcomere from stretching so much that you can't contract your muscle
Bone structure
154
What happens when the sarcomere length gets shorter?
Thin filaments start hitting the M line which decreases the tension that can be produced
155
Twitch
Non useful contraction
156
What starts a twitch
A stimulus/Acetylcholine being delivered
157
Phases of a twitch
1. Latent period
2. Contraction phase
3. Relaxation phase
158
Latent period
No tension is produced; The action potential arrives and goes through the T tubules then to the sarcoplasmic reticulum, which releases calcium to the sarcomere
159
Contraction phase
Tension begins when calcium binds to troponin and a cross bridge is formed
160
Relaxation phase
Muscle is getting rid of calcium
161
What gets rid of calcium?
The sarcoplasmic reticulum
162
What happens in repeated stimulations
Before all of the calcium ions can be taken by the sarcoplasmic reticulum, an action potential comes through again. This means there are more calcium ions for the 2nd contraction, making the tension greater for each stimulation
163
Tetanus
A useful muscle contraction; when there is little time for relaxation and the tension is greatest
164
Motor unit
One motor neuron forming a synapse on multiple muscle cells
165
Small motor units
Control about 5-10 muscle fibers
166
Large motor units
Control about 500-1000 muscle fibers
167
Why do we have different sized motor units?
1. Helps control muscle tension
| 2. The motor units cycle, so that they don’t all get fatigued at once
168
Asynchronous motor unit summation
In this "relay team" approach, each motor unit can recover somewhat before it is stimulated again
169
Fast twitch muscle
Gives brief and precise movements; has a very small blood supply
170
Slow twitch muscle
Muscles that give sustained contractions over a long period of time; has a larger blood supply; has myoglobin
171
Example of slow twitch muscle
Legs
172
Myoglobin
A form of hemoglobin found in muscles; stores oxygen
