1
Q
Function of osteoprogenitor cells
A
squamous stem cells that divide to produce daughter cells that differentiate into osteoblasts
2
Q
Function of osteoblasts
A
bone cells that are responsible for bone formation
3
Q
Function of osteocytes
A
Mature bone cell
4
Q
Function of osteoclasts
A
Large bone cells that break down bone cells
5
Q
Components of the bone matrix
A
- collagen
- calcium
- magnesium and fluoride ions
- phosphorus
6
Q
Which inorganic material makes of the bone matrix
A
calcium hydroxyapatite
7
Q
Function of calcium hydroxyapatite
A
- Mineralize the osteoid produced by osteoblasts
- Provide strength and hardness to the bone
- House the body’s mineral reserves, including:
1. 99% of the body’s calcium
2. 85% of its phosphorous
3. 65% of its sodium and magnesium
8
Q
What organic material makes up the bone matrix?
A
- 90% type 1 collagen
- 10% noncollagenous proteins
9
Q
Function of organic material in the bone matrix
A
strengthen the bone
10
Q
What is endochondral ossification?
A
type of bone growth that replaces existing cartilage and grows in length/width
11
Q
What bone shape does endochondral ossification make?
A
long bones
12
Q
Endochondral ossification: Are blood vessels in the original tissue already, or do they need to enter as part of the bone forming process?
A
Enters the bone during the process
13
Q
What is intramembranous ossification?
A
type of bone growth that develops directly from embryonic tissue
14
Q
What type of bones form from intramembranous ossification
A
flat bones
15
Q
Intramembranous ossification: Are blood vessels in the original tissue already, or do they need to enter as part of the bone forming process?
A
Blood vessels are already within the tissue
16
Q
Which organ releases calcitonin?
A
thyroid gland
17
Q
Function of calcitonin
A
released when blood calcium is too high and lowers blood calcium levels
18
Q
Calcitonin effect on kidneys, intestines, and osteoclasts
A
kidneys: allow more calcium loss
intestines: rate of intestinal absorption decreases
osteoclasts: inhibits them which reduces calcium absorption
19
Q
Which organ releases parathyroid hormone (PTH)?
A
parathyroid glands
20
Q
Function of PTH
A
releases when blood calcium is too low and raises blood calcium levels
21
Q
PTH effect on kidneys, intestines, and osteoclasts
A
kidneys: retain more calcium ions
intestines: rate of intestinal absorption increases
osteoclasts: activates them which increases calcium absorption
22
Q
Difference between osteopenia and osteoporosis
A
Osteopenia: bones become weaker and thinner with age
Osteoporosis: condition where a lot of bone loss occurs
23
Q
Which portion of the long bone is where the primary ossification center is developed?
A
diaphysis
24
Q
Which type of bone cell is responsible for maintaining bone matrix within a lacuna?
A
osteocyte
25
Put the following events of intramembranous ossification in the right order.
- Mesenchymal cells give rise to osteoblasts.
- Spicules condense to form trabeculae.
- Osteoblasts form spicules.
__1__ Mesenchymal cells give rise to osteoblasts.
__3__ Spicules condense to form trabeculae.
__2__ Osteoblasts form spicules.
26
If there is more osteoclast activity than osteoblast activity in a given bone, then the bone will:
shrink
27
Ahmad has a parathyroid tumor that results in excess parathyroid hormone. Answer the following questions about how the effects of this:
How will this affect Ahmad’s bones?
Describe how the kidneys will be affected.
Describe how the intestines will be affected.
How will this affect his blood calcium levels?
1. excess PTH will cause the bones to become weaker and more fragile. PTH stimulates the osteoclasts to breakdown bone to increase the blood calcium levels
2. the kidneys will retain an excess of calcium which will then lead to too much calcium in the blood
3. the intestines will have an increased rate of absorption of calcium from the diet
4. as a result the blood calcium levels for this patient will be highly increased
28
A 45 year old patient comes to your office because they have broken a few bones in the last year. A DEXA scan shows they have low bone density. Describe at least 6 different specific levels (ex: minerals, vitamins, hormones, etc) you would want to check in their blood to see what could be the root cause of this bone loss.
parathyroid hormone - increases blood calcium levels
calcitonin - decreases blood calcium levels
calcium - makes bones stronger
vitamin D - helps make calcitriol
vitamin C - stimulates osteoblast differentiation
calcitriol - regulates calcium and phosphate levels
29
Compare and contrast endochondral and intramembranous ossification by writing at least 3 similarities and 3 differences
similarities:
- spongy bone occurs first
- same cells are used
- forms both spongy and compact bone
differences:
- E: forms long bones I: forms flat bones
- E: blood vessels grow into the bone I: blood vessels are already present
- E: growth occurs by replacing existing cartilage I: derives from embryonic connective tissue
30
Put the following steps of bone repair in the correct order.
- A blood clot (hematoma) is formed to prevent blood loss.
- Remodeling is done by osteoblasts and osteoclasts.
- An internal and external callus are created.
- Spongy bone is created by osteoblasts.
__1__ A blood clot (hematoma) is formed to prevent blood loss.
__2__ An internal and external callus are created.
__3__ Spongy bone is created by osteoblasts.
__4__ Remodeling is done by osteoblasts and osteoclasts.
31
What type of movement is done when shrugging your shoulders up?
elevation
32
True or false: The joint between vertebral bodies is an amphiarthrotic joint, while the joint between articular processes of the vertebrae is a diarthrotic joint.
true
33
Which joint can do the actions of elevation, depression, retraction, and protraction?
- knee
- elbow
- hip
- temperomandibular
temperomandibular
34
Rheumatoid arthritis
autoimmune disorder that causes joint inflammation
35
The functional classification of joints is based on
the amount of movement allowed by the joint
36
Movement of a limb away from the midline or median plane of the body along the frontal plane is known as
abduction
37
Movement of the ankle joint that lifts the foot so that its superior surface approaches the shin is
dorsiflexion
38
the least stable and most flexible joint in the body.
shoulder
39
Compare the shoulder joint and hip joint. Discuss at least two similarities and at least two differences. Be as specific as possible, and make sure that you are relating them, not just listing everything you know about each.
similarities:
both are synovial joints
both are ball and socket joint
both allow for diarthrotic movement
differences:
H: deeper socket makes it more stable S: more shallow socket allows for less stability
H: prone to less injury due to higher stability S: prone to more injury due to less stability
H: bones involved are the femur and the os coxa S: bones involved are the humerus and scapula
40
Describe in detail the relationship between strength and mobility in regard to joints. Why is this? Give an example of a really strong joint and a really weak joint and describe their range of motions. (in context of all of the joints in the body).
In regard to joints, the more mobile it is, the less strength it has. The shoulder is a ball and socket joint that has a free range of motion. Because this joint has high mobility, it is relatively weak and is prone to injury. On the opposite end, a suture is a fibrous joint that allows for no movement at all. This joint allows for no movement because it has strong collagen fibers holding the joint together
41
Describe sprain
ligaments with torn
collagen fibers
42
Why do osteocytes need canaliculi
they allow for essential nutrient and waste exchange between cells and blood vessels
42
What structures make synovial joints less stable than synarthrosis joints
- lack of tough collagen fibers holding bones together
43
Why is the hip more stable than the shoulder
- patella covering
- deeper socket
44
Describe two structure that are unique to skeletal muscle cells and why they have those structures
45
Compare and contrast osteocytes and osteoclasts
46
Compare and contrast knee and elbow joint
47
Compare and contrast cartilaginous, fibrous, and synovial joints
48
Compare and contrast skeletal, cardiac, and smooth muscle
49
Compare and contrast isotonic and isometric contraction
50
Compare and contrast ATP production during sprinting, endurance exercise, and rest
51
Process of endochondral ossification
- cartilage and chondrocytes enlarge
- blood vessels grow around the edge of the cartilage
- blood vessels penetrate the cartilage and invade the central region
52
3 general stages of muscle contraction
- neuromuscular junction
- excitation contraction coupling
- contraction cycle
53
What occurs during the neuromuscular junction phase
- action potential travels along the motor neuron and ends at the synaptic terminal
- synaptic terminal will release a neurotransmitter (acetylcholine; skeletal muscle only) into the synaptic cleft
- neurotransmitter will bind to receptors in the sarcolemma
54
What occurs during the excitation contraction coupling phase
- new actional potential (sodium ions) is triggered in the sarcolemma
- travels through the T tubules
- when action potential reached the terminal cisternae of the sarcoplasmic reticulum, calcium gates open
- calcium ions are then released around the myofibrils
- calcium activates the active sites of actin
- calcium binds to troponin and moves tropomyosin to expose the active sites
55
What occurs during the contraction cycle phase
- calcium binds to troponin and moves tropomyosin to expose the active sites (ATP molecule within myosin is split up into ADP and phosphate)
- the myosin heads bind to the now exposed actin sites (cross bridge formation)
- ADP and phosphate move off of the myosin heads which then causes the myosin head to pivot and cause contraction
- new ATP molecule binds to the now empty myosin head and allows it to detach from the active site
- the repivot the myosin to its original position the ATP molecule splits into ADP and phosphate and the cycle repeats as long as calcium is present
56
What factors influence the amount of tension of a single muscle fiber
- optimal length between thin and thick filaments
- increasing frequency of neural stimulation
57
What would happen if someone had a thyroid tumor, resulting in excess
calcitonin?
- calcitonin decreases blood calcium levels
- kidneys will excrete more calcium
- rate of absorption intestines will decrease
- osteoclast activity will be inhibited
58
What would happen if a patient does not move their knee for an extended
period of time?
- there will be a lack of nutrient delivery and removal of waste because the synovial fluid will be motionless
- surrounding muscles will become weak
- immobility can lead to pain and stiffness
59
What would happen if the sarcoplasmic reticulum does not function properly
- calcium can no longer be effectively stored and will continuously release
- muscles will be constantly contracted due to the excessive calcium
60
If a person is unable to put weight on their legs, describe how the bones
and muscles would change
- muscle atrophy
- bones will reform to match the current level of activity; bones will shrink
61
Describe isotonic contractions
- contraction that shortens or lengthens a muscle
- ex: flexing with a dumbbell
- two types: concentric and eccentric
62
Describe concentric contractions
- muscle contraction that shortens the muscle
- ex: flexing upwards with a dumbbell
63
Describe eccentric contractions
- muscle contraction that lengthens the muscle
- ex: flexing downwards with a dumbbell
64
Describe isometric contractions
- contraction of the muscle but the muscle is not moving
- ex: holding a dumbbell
- muscle is contracting; shortening of sarcomeres; muscle is not shortening
65
What joint movements are involved with running
- flexion and extension of the hip, knee, and shoulder
- dorsiflexion and plantarflexion of the foot
- inversion and eversion of the foot for stability
BI 231 Exams
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