Practice Q's - Bone
what two factors will cause an increase in blood calcium levels?
PTH vitamin D
Which type of bone is always produced first, whether during intramembranous ossification, endochondral ossification, or during fracture repair?
Spongy bone
__________ is required for collagen synthesis, and a deficit of it results in a condition called scurvy.
Vitamin C
A girl born with nonfunctioning ovaries could be expected to have a deficiency in the activity of which type of cell?
osteoblasts
what secretes osteoid?
osteoblasts
what helps form the hydroxyapatite crystals?
osteocalcin
when calcium levels are low, vitamin d will stimulate
osteoclast activity (bone resorption)
Which of the following hormones does NOT stimulate osteoblasts?
parathryoid hormone
Describe in detail how vitamin D increases calcium absorption in the enterocyte when blood calcium is low.
When 1,25(OH)2 D synthesis is increased in the kidney. this causes increased binding to the vitamin D receptor. Which increases calbindin synthesis. Increased calbindin cause an increase in calcium uptake and absorption.
Appositional bone growth at the outer surface results in __________.
an increase in the diameter of a growing bone
osteoblasts decrease
blood Ca levels
osteoclasts increase
blood Ca levels
osteocalcin is a bone matrix protein made by osteoblasts that may aid in
bone formation
how do osteoblasts create an alkaline environment?
by using alkaline phosphatase which hydrolzyes monophosphate esters releasing alot of phosphate in the area
what is required for the transport of calcium from the intestine to the bloodstream?
calbindin
what factor will cause a decrease?
calcitonin
what is the name of the active form of vitamin d
calcitriol
The region known as the epiphyseal plate is the area where __________.
cartilage being replaced by bone
Vitamin C is needed for
collagen synthesis in connective tissues
The process during which bones begin development as cartilage models and the cartilage is later replaced by bone is called __________.
endochondral
what happens when you have deformed osteocalcin which causes deformed hydroxyapetite crystals?
fracturing and breaking of bone
what does PTH do?
increase resorption of bone
Calcitonin __________________.
inhibits the reabsorption of calcium and phosphate in the kidneys
Which of the following forms the flat bones of the skull?
intramembranous ossification
where does the active vitamin d become formed at?
kidney
In both intramembranous and endochondral ossification, the first stage of development of bone is the migration of ________ cells into the area where the bone will form.
mesenchyme
alkaine environment mineralize or demineralize bone?
mineralize
when have a lower level of estrogen we get?
more apoptosis of osteoblasts. less osteoblasts.
Spongy bone is filled with ____________. compact bone red marrow the osteons fatty marrow
red marrow
The synthesis of 1,25-dihydroxyvitamin D3 _____________.
requires a hydroxylation reaction using an enzyme made in the kidneys
how do osteoblasts mineralize the matrix?
secreting calcium via matrix vesicle into the matrix.
how does PTH contribute to forming active vitamin D?
stimulates the kidney hydroxylase
how does vitamin d stimulate osteoblast activity?
stimulates the secretion of osteocalcin. which in turn, helps form the hydroxyapetite crystals. (when blood calcium levels are normal or high)
what is an osteoid?
the organic part of the matrix of bone
why are hydroxyapetite crystals important?
they prevent breaking or fracture of bone have a lot of resistance and very strong
osteoid is what type of collagen?
type I
what form of vitamin D action is to induce the synthesis of calcium binding protein Calbindin D in intestinal epithelial cells, this is necessary for Ca absorption in the small intestine and consequently bone mineralization?
1, 25-dihydroxycholecalciferol (1,25-diOH D3).
Area where bone growth takes place A) epiphyseal plate B) canaliculi C) Sharpey's fibers D) osteoblasts E) osteons F) epiphyseal line G) lacunae H) lamellae I) osteocytes J) osteoclasts
A
Based on shape, a vertebra is an example of a(n) __________ bone. irregular dense flat short
A
Bone resorption is produced by the action of _____________, which return bone calcium and phosphate to the blood. a. osteoclasts b. calcitonin c. osteoblasts d. osteocytes
A
In adults, the function of the yellow marrow is to: A) store adipose tissue B) form blood cells C) store calcium and phosphorus D) cause lengthwise growth in long bones E) decrease friction at joint surfaces
A
The inactive form of vitamin D (25-hydroxy Vitamin D) is metabolized via the kidney to produce Calcitriol (1, 25-dihydroxy Vitamin D). a. True b. False
A
The interconnecting tiny arches of bone tissue found in spongy bone are called trabeculae. interstitial lamellae. concentric lamellae. lacunae. osteons.
A
The small cavities in bone tissue where osteocytes are found are called: A) lacunae B) Volkmann's canals C) Haversian canals D) trabeculae E) lamellae
A
To mobilize calcium from bone, osteoclasts bind to bone and transport ________ into the bone matrix to dissolve calcium. a. H+ b. PTH c. phosphate d. calcitonin
A
What is the structural unit of compact bone? osteon canaliculus osteoid haversian canal
A
Which of the following is formed immediately after a fracture? hematoma external callus spongy bone internal callus
A
Which of the following would NOT be a way that parathyroid hormone (PTH) could alter plasma calcium levels? (Which one of the following is FALSE?) increase osteoblasts on bone increase osteoclasts increase reabsorption of calcium in the kidney
A
Which statement concerning endochondral ossification is the most accurate? A primary ossification center begins replacing cartilage in the central region of the cartilage rod. A bone collar forms around the ends of the cartilage rod. The ends of the cartilage rod are converted into bone first. The epiphyseal plate is an area of bone that joins the shaft of the cartilage rod to the ends of the rod.
A
Wolff's law is concerned with ________. the thickness and shape of a bone being dependent on stresses placed upon it the diameter of the bone being dependent on the ratio of osteoblasts to osteoclasts the function of bone being dependent on shape vertical growth of bones being dependent on age
A
________ cells are located in the inner cellular layer of the periosteum. Osteoprogenitor Osteoclast Chondroblast Osteocyte Osteoid
A
Why is vitamin C essential to bone health? It is needed in the enzymatic reactions used to make collagen. It stimulates osteoblast activity. It prevents the development of scurvy.
All the above
A drop in blood calcium levels stimulates the secretion of __________. thyroxine parathyroid hormone calcitonin growth hormone
B
Accelerated closure of the epiphyseal plates could be caused by too little thyroxine. elevated levels of estrogen. high levels of vitamin D. an excess of growth hormone. too much calcium in the diet.
B
Aging has what effect on the skeletal system? fusion of joints, especially syndesmoses loss of calcium and collagen fibers from matrix progressive loss of processes and tuberosities increase in the number of cranial foramina increase in adipose tissue in epiphyses
B
Calcitonin causes what response in the kidneys? -inhibited osteoclast activity -decreased absorption of calcium -elimination of calcium ions into the urine -increased rate of calcium uptake by the kidney
C
Cells synthesizing hydroxyapatite in bones are termed a. osteoclasts. a. osteosarcoma cells. c. osteoblasts. d. osteocytes.
C
Migration of osteoblasts into the __________ creates the __________. -diaphysis; secondary ossification center -epiphysis; primary ossification center -epiphysis; secondary ossification center -diaphysis; tertiary ossification center
C
Osteons are characteristic of __________. A) articular cartilage B) spongy bone C) compact bone D) yellow marrow E) Sharpey's fibers
C
Parathyroid hormone (PTH) ______________. A) is released from the parathyroid glands when blood Ca++ levels rise B) inhibits osteoclast activity C) increases Ca++ (but not phosphate) reabsorption from the glomerular filtrate of kidney nephrons D) inhibits the formation of 1,25-dihydroxyvitamin D3
C
The process of bone recycling and renewal is known as __________. fracture repair metabolic turnover remodeling the cartilage model
C
The shaft of a long bone is also called the __________. metaphysis medullary cavity diaphysis epiphysis
C
What is absolutely required for bone growth or healing from a fracture? osteoclasts dietary intake of calcium and vitamin D osteoblasts osteocytes
C
What is endochondral ossification? the formation of bone from fibrous membranes the formation of bone from pre-existing fibrocartilage models the formation of bone from pre-existing hyaline cartilage models the formation of bone from pre-existing elastic cartilage models
C
What is the final stage in the healing of a bone fracture? formation of a bony callus formation of a hematoma bone remodeling formation of a fibrocartilaginous callus
C
What is the major advantage or advantages of bones undergoing continual remodeling? A It may change the internal structure of a bone. B It may change the shape of a bone. C All of the listed responses are correct. D It may change the total amount of minerals deposited in the bones.
C
What type of cell does parathyroid hormone (PTH) activate: A) osteocyte B) osteoblast C) osteoclast D) periosteum E) lacunae
C
What type of tissue is replaced by bone in intramembranous ossification? A Epithelium B Dense fibrous connective tissue C Mesenchyme or embryonic fibrous connective tissue D Cartilage`
C
When a fractured bone heals it leaves a thickened region known as a ____________. fracture hematoma callus bone scab tuberosity
C
When the epiphyseal plate is replaced by bone, interstitial bone growth begins. appositional bone growth begins. long bones have reached their adult length. puberty begins. the bone becomes more brittle.
C
A bone scan of an older patient revealed the beginnings of osteoporosis. Which of these interventions is NOT recommended? calcium supplements vitamin D supplements vitamin C supplements bed rest
D
A fracture in the shaft of a bone would be a break in the ________. metaphysis articular cartilage epiphysis diaphysis
D
Calcitriol is required for __________. collagen synthesis activating osteoclasts quieting osteoblasts absorbing dietary calcium and phosphate
D
Cells that can build bony matrix A) epiphyseal plate B) canaliculi C) Sharpey's fibers D) osteoblasts E) osteons F) epiphyseal line G) lacunae H) lamellae I) osteocytes J) osteoclasts
D
In the epiphyseal plate, cartilage grows ________. from the edges inward in a circular fashion by pulling the diaphysis toward the epiphysis by pushing the epiphysis away from the diaphysis
D
In which of the following does bone replace existing cartilage? A Dermal ossification B Osteolysis C Intramembranous ossification D Endochondral ossification
D
Ossification of the ends of long bones ________. takes twice as long as diaphysis ossification involves medullary cavity formation is a characteristic of intramembranous bone formation is produced by secondary ossification centers
D
Osteoclast (growth or function) is inhibited by a. calcitonin. b. osteoprotegrin. c. osteoblasts. d. all of the choices are correct.
D
Roger has been lifting weights seriously for years. His twin brother Steven does not exercise regularly. Which of the following statements would be a reasonable hypothesis to make regarding differences between their skeletons? -Steven's hydroxyapatite-collagen combination is less than Roger's. -Roger's skeleton undergoes less osteolysis than Steven's. -Roger's osteoblasts are more active than Steven's. -All of the listed responses are correct
D
The canal that runs through the core of each osteon contains: A) cartilage and lamellae B) osteoclasts and osteoblasts C) yellow marrow and Sharpey's fibers D) blood vessels and nerve fibers E) red marrow
D
The hormone __________ increases the blood level of calcium. calcitriol growth hormone calcitonin parathyroid hormone
D
The most important minerals stored in bones are: A) calcium and iron B) sodium and phosphorus C) sodium and potassium D) calcium and phosphorus E) calcium and potassium
D
What indicates that a long bone has reached its adult length? the presence of hyaline cartilage on the ends of the bone the presence of osteons the presence of osteoblasts closure of the epiphyseal plate
D
What is normally found at a fracture hematoma? blood clot bone fragments dead bone All of these are found at the site of a fracture hematoma.
D
What kind of tissue is the forerunner of long bones in the embryo: A) elastic connective tissue B) dense fibrous connective tissue C) fibrocartilage D) hyaline cartilage E) loose fibrous connective tissue
D
When production of sex hormones increases at puberty, epiphyseal plates increase slowly. accelerate rapidly, but mostly in thickness. are hardly affected. get wider. become narrower.
D
Where in the body does the production of precursors for the synthesis of calcitriol occur? small intestine kidneys bone skin liver
D
Which of the following characteristics applies to the cells known as osteoclasts? They are mature bone cells. The cells secrete matrix. They are stem cells. The cells dissolve matrix
D
Which of these are bone-forming cells: A) osteocytes B) canaliculi C) osteoclasts D) osteoblasts E) lamellae
D
The bone cells within lacunae receive nourishment from blood vessels through passageways called: A) Haversian canals B) perforating canals C) lamellae D) medullary cavities E) canaliculi
E
The presence of an epiphyseal plate indicates that: A) bone is dead B) bone length is no longer increasing C) bone diameter is increasing D) bone diameter is decreasing E) bone length is increasing
E
There are four stages in the healing of a bone fracture. Which of the following best illustrates the sequence of these stages: 1. bony callus formation 3. fibrocartilage callus formation 2. bone remodeling 4. hematoma formation A) 4, 3, 2, 1 B) 1, 3, 4, 2 C) 1, 2, 3, 4 D) 1, 3, 2, 4 E) 4, 3, 1, 2
E
Through the action of osteoclasts, osteoid is calcified. new bone is formed. an organic framework is formed. fractured bones regenerate. bony matrix is dissolved
E
what type of tissue covers the epiphysis of bones and reduces friction to the joints a. yellow marrow b. endosteum c. spongy bone d. periosteum e. articular cartilage
E
25(OH)D3 is the active form of vitamin D, which is created by 25-hydroxylase in the kidney. T F
False 25(OH)D3 is the CIRCULATING of vitamin D created by 25- Hydroxylase in the LIVER
Vitamin D2 is produced by animals, has an additional double bond, and increases 25(OH)D levels more than vitamin D3 . T F
False VITAMIN D3 is produced by animals and DOES NOT have an additional double bond and increases 25(OH)D levels more than vitamin D2
Layers of calcification that are found in bone A) epiphyseal plate B) canaliculi C) Sharpey's fibers D) osteoblasts E) osteons F) epiphyseal line G) lacunae H) lamellae I) osteocytes J) osteoclasts
H
VITAMIN D increases or decreases blood calcium levels?!
INCREASES
Alice and James adopted a 3-year-old child from a developing country. They noticed that her legs were bowed and there were some deformities in her cranial and pelvic bones. They brought her to a physician for a diagnosis. What was the diagnosis, and what was the treatment for the disorder? The child most likely has Paget's disease. Treatment includes drug therapy with administration of calcitonin and bisphosphonates. The child most likely has rickets. Treatment is to increase the intake of calcium and vitamin D in the diet, and to get some sunshine every day. The child most likely has osteomalacia. Treatment is to increase the intake of calcium and vitamin D in the diet, and to get some sunshine every day. The child most likely has osteoporosis. Treatment is to increase the intake of calcium and vitamin D, and performance of weight-bearing exercises.
B
Calcitriol is required for __________. activating osteoclasts absorbing dietary calcium and phosphate collagen synthesis inhibiting osteoclasts
B
Choose the TRUE statement. Most bones in the body are formed by intramembranous ossification. Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). Endochondral ossification leads to the formation of the clavicles and cranial bones. Endochondral ossification occurs within fibrous connective tissue membranes.
B
During endochondral bone formation, the primary ossification center is located in the __________. distal epiphysis diaphysis metaphysis proximal epiphysis`
B
Fat is stored within the metaphysis. medullary cavity. spongy bone. diaphysis. epiphysis.
B
Hypercalcemia can be caused by_________. insufficient vitamin D levels in the body hypersecretion of parathyroid hormone reduced parafollicular cell activity All of the listed responses are correct
B
Normal bone formation and growth are dependent on the adequate intake of ________. vitamin D, phosphate, and chloride calcium, phosphate, and vitamin D potassium, phosphate, and vitamin D sodium, calcium, and vitamin E
B
Osteoblasts differentiate from __________. osteocytes osteogenic cells osteomedullary cells osteoclasts
B
Small channels that radiate through the matrix of bone A) epiphyseal plate B) canaliculi C) Sharpey's fibers D) osteoblasts E) osteons F) epiphyseal line G) lacunae H) lamellae I) osteocytes J) osteoclasts
B
The cell responsible for secreting the matrix of bone is the ________. osteoclast osteoblast chondrocyte osteocyte
B
The most abundant cell type in bone is osteoclasts. osteocytes. osteoprogenitor cells. osteolytes. osteoblasts.
B
The outer dense connective tissue of a bone, the periosteum, ________. A actively participates in bone growth and repair B isolates the bone from surrounding tissues, provides a route for circulatory and nervous supply, and actively participates in bone growth and repair C provides a route for circulatory and nervous supply D isolates the bone from surrounding tissues
B
The trabeculae of spongy bone are composed mostly of cartilage will collapse under stress. are organized along stress lines. are concentrated in the cortex of the diaphysis. are organized parallel to the long axis of the bone.
B
What is the term for the process in which the organic and mineral components of bone are continuously recycled and renewed? A Calcification B Remodeling C Osteolysis D Ossification
B
Which hormone increases blood calcium upon secretion? estrogen and testosterone parathyroid hormone (PTH) calcitonin growth hormone
B
Which of the following is stored in bones? iodine phosphate vitamin C glycogen calcitonin
B
Which of the following statements are true regarding calcitonin? a. Calcitonin can inhibit osteoclast secretory activity and stimulate osteoblast activity in the bone b. Calcitonin can enhance renal tubular reabsorption of calcium c. Calcitonin is released by the parathyroid gland in the presence of increased serum calcium d. Calcitonin is not involved in calcium homeostasis
B
Which of these forms by intramembranous bone formation? mandible carpal bones long bones humerus
B
Which type of cartilage covers and protects the ends of bones at freely moveable joints? elastic cartilage hyaline cartilage fibrocartilage both hyaline and elastic cartilage
B
________ account(s) for almost two-thirds of the weight of bone. Water Fluoride Calcium phosphate Calcium carbonate Collagen fibers
B
Cells that can dissolve the bony matrix A) epiphyseal plate B) canaliculi C) Sharpey's fibers D) osteoblasts E) osteons F) epiphyseal line G) lacunae H) lamellae I) osteocytes J) osteoclast
J
The trabeculae of spongy bone are oriented toward lines of stress. T F
T
