Lecture, 6- The Skeletal System

An increase in bone growth is promoted by which hormones?

Calcitonin and Calcitrol

Bone mass reduction is promoted by which hormone?

PTH

In a newborn, all bone marrow is red, which means all of the infant's marrow can make blood cells.

True

Roles of (PTH) parathyroid hormone's control of blood calcium levels?

1. In response to low Ca2+ levels, cells of the parathyroid gland speed up synthesis of PTH (parathyroid hormone) 2. PTH acts on the kidneys to decrease excretion of calcium in the urine. 3. PTH stimulates the conversion of vitamin D into its active form (calcitriol) 4. PTH increases the number and activity of osteoclasts which dissolve bone matrix and release Ca2+ to diffuse into the blood streamPTH increases the number and activity of osteoclasts which dissolve bone matrix and release Ca2+ to diffuse into the blood stream.

Which of the following is a function of calcium in the body?

1. nerve cells require extracellular calcium ions (Ca2+) for proper functioning 2. Ca2+ is a cofactor needed for many enzymes to function properly 3. Ca2+ is required for the process of blood clotting 4. Ca2+ is needed by muscle cells for contraction

Where in the diagram is the proximal epiphysis?

A

Which of the following tissues could be found on or within a bone, such as the humerus?

Adipose tissue, Nervous Tissue, Cartilage, and Osseous Tissue

During childhood, bones growth in diameter by

Appositional Growth

Osteoblasts _____ bone tissues, while osteoclasts _____ bone tissues.

Build Up, Break Down

Functions of Calcium in the body:

Blood Clotting Nerve Function Cofactor for many enzymes Muscle funtion

Which bone cell in the diagram below is a mature bone cell that helps maintain bone tissue?

C; Osteocyte

Which two minerals are stored in major quantities in bone tissue?

Calcium & Phosphorus

Which is secreted by osteoblasts during bone deposition?

Collagen Fibers

Which bone cell in the diagram below is an osteoclast?

D

What is another name for the shaft of a long bone?

Diaphysis

In the diagram, where is the central (Haversian) canal?

E

Where in the diagram is the endosteum located?

E

Which region of a long bone articulates with other bones?

Epiphyses

Once osteoblasts have surrounded themselves with the extracellular matrix of bone tissue, they remain inside little chambers called __________ where they carry on the metabolic functions that maintain bone tissue. At this point, the cells are called osteocytes.

Lacunae

Bones grow in length via osteoclast activity at both the periosteum and endosteum in order to

Maintain shape and articulation

The hollow, cylindrical space within the diaphysis that contains fatty, yellow bone marrow in adults is called the

Medullary Cavity

What is the region of long bone found between the diaphysis and the epiphysis called?

Metaphysis

What type of bone cell starts forming the bone matrix?

Osteoblast; B

Which is formed from the fusion of as many as 50 monocytes (a type of white blood cell)?

Osteoclast; Bone destroying cells, Maintenance and Repair of bone

Which represents the correct sequence of development of bone cells?

Osteogenic Cells, Osteoblasts, Osteocytes

Which of the following hormones is the most important for Ca2+ regulation?

Parathyroid Hormone

Bone tissue stores 99% of the body's calcium. Calcium plays important roles beyond the mineralization of bones. The exchange of calcium between bone and body fluids (especially the blood) is regulated by several hormones. Which of the following is the most important hormone regulating calcium exchange?

Parathyroid Hormone (PTH)

The coating around bones is called the

Periosteum

The coating around bones that contains stems cells for osteoblasts and chondroblasts is called the

Periosteum

What is the fibrous covering on the surface of bone that is involved in thickening of the bone called?

Periosteum

Where in the diagram can you find red bone marrow in an adult?

Spongy Bone & Proximal Epiphyses

Bone can be classified as a connective tissue because it contains an extracellular matrix that surrounds widely spaced cells.

True

Bone remodeling, especially bone resorption, plays a role in the maintenance of proper levels of calcium in the blood.

True

Bones can only assist in providing movement when they tugged on by the appropriate skeletal muscles.

True

Calcitonin inhibits activity of osteoclasts, speeds blood calcium uptake by bone, and accelerates calcium deposition into bones.

True

Trabeculae are filled with

Yellow and Red Marrow