Chapter 7 Worksheet

Complete each sentence by dragging the proper word or phrase into the appropriate position.

- Elongation of bones is accomplished via INTERSITIAL growth. - Growth in the epiphyseal plate adds to the LENGTH of a bone until the plate is depleted in early adulthood. - The EPIPHYSEAL PLATE is a layer of hyaline cartilage with a metaphysis on each side. - When the cartilage is depleted, the epiphyseal plates CLOSE, and the bone can get no longer. - The internal mark in the bone left behind by the closed epiphyseal plate is called the EPIPHYSEAL LINE.

Complete each sentence regarding skeletal function by dragging the proper word or phrase into the appropriate position.

- The bones of the skeleton provide structure to the body and serve as a SUPPORT to hold up the body and maintain proper positioning of some organs. - The skull, pelvis, ribs, vertebral column, and sternum provide PROTECTION to many delicate organs of the body by encasing them in hardened, shell-like or caged structures. - The MOVEMENT of the entire skeleton or skeletal elements utilizes the anchoring of muscles to attachment sites on the bones, which then serve as levers. - Minerals can be stored in the skeleton, which acts as a reservoir, storing or releasing minerals as needed to maintain ELECTROLYTE BALANCE throughout the body. - The storage or release of buffering compounds works to aid the body in ACID-BASE balance. - Contained within the spongy sections of bones, red bone marrow is responsible for BLOOD FORMATION.

Complete each sentence explaining mineral homeostasis by dragging the proper word or phrase into the appropriate position.

- The most active form of VITAMIN D is called calcitriol. - Osteoblastic activity in children is stimulated by the hormone CALCITONIN. - When blood calcium levels drop, glands embedded in the posterior thyroid secrete PARATHYROID hormone, which stimulates osteoclastic activity. - The hormone CALCITRIOL influences both resorption and deposition of bone. - Vitamin D stimulates absorption of dietary calcium from the DIGESTIVE system.

Complete each sentence by dragging the proper word or phrase into the appropriate position.

- When levels of blood calcium DECREASE, parathyroid hormone is released from the four nodular parathyroid glands located on the posterior thyroid. - Parathyroid hormone causes an increase in the number of OSTEOCLASTS and greater rates of bone resorption. - At the level of the kidney, parathyroid hormone will decrease the amount of calcium excreted by increasing REABSORPTION from the kidney tubules. - Parathyroid hormone increases the renal conversion of CALCIDIOL TO CALCITRIOL, which secondarily works to increase calcium levels in the blood. - Inhibition of OSTEOBLASTS by parathyroid hormone occurs as a result of a decreased production of organic matrix. - As a result of direct actions on the target cells of the bone and kidneys along with an indirect action on the small intestine (calcitriol), parathyroid hormone works to INCREASE blood calcium levels.

Complete each sentence by dragging the proper word or phrase into the appropriate position. Then, place each sentence in the order of the mechanisms following the secretion of calcitonin.

- When levels of blood calcium increase in children, calcitonin is released from the C CELLS of the thyroid gland. - This circulating calcitonin inhibits OSTEOCLASTS and stimulates OSTEOBLASTS within minutes. - The effects on osteoclasts cause a decrease in bone resorption and a concurrent INCREASE in bone deposition due to the activity of osteoblasts. - The decline in bone breakdown and increased mineralization causes blood calcium to DECREASE back to normal levels.

Place a single word into each sentence to make it correct. Then, arrange the sentences into a logical paragraph order to describe the process of healing a fracture in bone.

1. Any break in a bone is called a FRACTURE, and repair is done in stages by the body. 2. A HEMATOMA will form and will turn into granulation tissue at the site of injury. 3. Depositions of collagen and fibrocartilage will then turn the tissue into a soft CALLUS. 4. OSTEOBLASTS deposit a temporary bony collar around the fracture while ossification occurs. 5. The process finishes with bone REMODELING converting spongy to compact bone.

Complete each sentence by dragging the proper word or phrase into the appropriate position. Then, place each sentence in the correct order of vitamin-D synthesis and its effects.

1. Sunlight contacting the epidermis converts 7-DEHYDROCHOLESTEROL to vitamin D₃, otherwise known as cholecalciferol. 2. Transported via the blood to the liver, CHOLECALCIFEROL is converted to calcidiol. 3. Calcidiol returns to the blood once again where transport to the kidneys then allows the final conversion to CALCITRIOL. 4. Now in the most active form, calcitriol acts to INCREASE blood calcium by acting on three target organs: 1) small intestine, 2) skeleton, and 3) KIDNEYS.

Complete each sentence by dragging the proper word or phrase into the appropriate position. Then, place each sentence in order from the largest to the smallest cavity size being described.

1. The MARROW CAVITIES are found deep in the diaphyses of long bones and are filled with yellow marrow in the adult. 2. Located in the middle of osteons, the CENTRAL CANALS contain the blood vessels and nervous supply of the compact bones. 3. Filled with OSTEOCYTES, which are osteoblasts encased in matrix, LUCUNAE are found between layers of concentric lamellae. 4. Osteocytes maintain contact with neighboring osteocytes in adjacent lamellae via dendrite-like extensions through CANALICULI.

At which of the following ages would calcium loss from bone be more than calcium deposits into bone, even when a high calcium diet is eaten?

50 years old

Which of the following best describes osseous tissue?

A connective tissue with a hardened matrix that makes up bone

Each of the following complications listed below is a result of a homeostatic calcium imbalance. Which would not be life threatening?

A deficit of appositional bone growth

What is the function of red bone marrow?

Blood-cell production

Which hormone inhibits osteoclasts and stimulates osteoblasts to lower blood calcium levels?

Calcitonin

Which mineral is most important throughout life to assist in maintaining strong bones?

Calcium

__________ is/are found in compact bone but not spongy bone.

Central canals

Which osseous tissue is found on the surface of bones and composed of tightly arranged parallel osteons?

Compact

Where does bone formation occur during endochondral ossification?

Hyaline cartilage model

Which type of bone growth occurs within cartilage and results in bone elongation?

Interstitial

The bones of the skull form by which type of ossification?

Intramembranous

Which bone cells produce the soft organic bone matrix?

Osteoblasts

Match the name of the bone disease to the correct description of its pathology.

Osteoporosis: - Most common bone disease; results in a severe bone-density loss Osteosarcoma: - The most common and deadly form of bone cancer Osteogenesis Imperfecta: - Defect of collagen deposition that renders the bones exceptionally brittle Osteomyelitis: - Inflammation resulting from a bacterial infection Osteitis Deformans (Paget's disease): - Involves excessive proliferation of osteoclasts, leading to rapid, disorderly bone remodeling and weak, deformed bones

In an adult, which of the following is a bone that does not contain red bone marrow?

Skull

Which of the following is not considered a weight bearing activity?

Swimming

Which of the following is not a component of the skeletal system?

Tendons

Which of the following best describes osteomalacia?

The softening of the bones in adults due to calcium depletion

The skeletal system helps maintain acid-base balance by __________.

absorbing or releasing alkaline phosphate and carbonate salts

Osseous tissue matrix is composed of __________.

calcium phosphate

Mineralization is a process that extracts __________ and __________ from the blood plasma and deposits it into bone.

calcium; phosphate

If the __________ component of bone is not in adequate amounts, the flexibility of bone will be compromised.

collagen

Osteogenesis imperfecta is due to the deficiency of __________ in the matrix, which makes the bones extremely brittle.

collagen

A __________ fracture is one in which the bone is broken into three or more pieces.

comminuted

Drag each label into the proper position to identify the type of bone described.

compact bone: - made up of osteons - also called dense bone - visible, obvious, central canals - found in greater proportion in the bone diaphysis spongy bone: - composed of trabeculae - convey strength with light weight - found in greater proportions in flat bones - gaps between ossified material are filled with marrow - arranged along the lines of forces that are encountered - found in greater proportions in bone epiphyses

During the healing of a bone fracture, a hard callus is formed by ___________.

osteoblasts

The __________ contain hydrogen pumps that lead to the formation of hydrochloric acid, which is used to dissolve bone minerals in a process called __________.

osteoclasts; mineral resorption

A(n) __________would not involve damage to the structures that comprise the skeletal system.

ruptured calcaneal (Achilles) tendon

Greenstick fractures most commonly occur in children because __________.

their bones contain a higher proportion of collagen

In an adult, a compound fracture of the __________ could lead to a "fat" embolism entering the blood stream.

tibia

Trusses and arches, which help form an internal scaffolding network, are found in __________.

trabecular bone