QUIZ 10/16 skeletal system 1

What is another term for the skeltal system?

Osteology

What are the five main functions of the skeletal system?

Support, Locomotion, Protection, Storage, Haemopoiesis

What are the three different types of skeleton?

Appendicular skeleton, Axial skeleton, Visceral skeleton

Appendoicular skeleton means…

Bones in limbs

Axial skeleton means…

Core bones (head, spine, ribs, tail)

Visceral skeleton means…

Weird extra bones (patella, ossicles in inner ear)

Bones are a reservoir for…

Calcium and phosphorus

How doews bone respond to injury?

Via rapid healing

What greatly affects bone?

Nutritional and metabolic changes

True or False: Bones are constantly being modified, reshaped, remodeled, and overhauled.

True

Three major compartments of bone

Cells, Organic matric, Mineral

What are the two organic matrixes found in bone?

Collage and Proteoglcans

Collagen gives bone the ability to…

Resist snapping and breaking

What is mineral within the bone made of?

Calcium phosphate crystals deposited as hydroxyapatite

How much of matured bone contains mineralized matter?

65%

What does the mineral component of the bone do to bones?

Gives bones it harness, rigidty

Lamellar Bone / Compact Bone def

Hard outer “shell”

What is found inside the hollow ends of each of the long bones?

A trabecular network of spongy (cancellous) bone

“Spongy bone” Def

Trabecular network; red or yellow marrow between spaces

Cortical Bone def

Heavy, dense, strong surface of bones; Protective outer layer

Epiphyseal plate is replaced by WHAT after growth?

Epiphyseal line

Young Bones def

Cartilaginous growth plate at one or both ends

Where does the replacement of cartilage by bone occur?

In endochondral ossification

Epiphysis Def

Elongation of the anatomic bone

How does cartilage proliferation work in Epiphysis?

Occurs rapidly; Keeps ahead of the encroaching wave of ossification (bone continues to elongate)

Circular areas in microscopic anatomy of bones…

Osteons (cortical bone)

What are the less regularly shaped regions?

Interstitial systems, Remnants of old osteons, Vary in size and shape

Osteon Def

Basic structural unit of compact bone; Cylinder composed of 4-20 concentric lamellae

Osteonal canal/Haversian canal

Route for blood vessels and nerves serving the osteons; Also includes lymphatic vessels, nervse fibers

Branches running adjacently to osteons pass through…

Lateral canals (Volkmann’s)

What are osteocytes trapped in?

Lacunae (between the hardened lamellae)

What radiates from each lucuna?

Thin canaliculi

Canaliculi Def

Thin, hair-like projections radiating from the lacunae tiny channels; Distribution of nutrients and removal of waste

Are bones vascular or avascular?

Heavily vascularized

Haversian and lateral (Volkmann’s) canals form a complicated set of channels through…

Dense bone

Where do the haversian and lateral (volkmann’s) canals bring blood?

Bring blood into the marrow cavity via perforating canals

How do newly formed blood cells get into general circulation?

Exit the marrow and enter general circulation through Haversian and Volkmann’s canals

What is the final level in distribution of nutrients and wastes?

The canaliculi (canalicular system)

Is there diffusion of nutrients in the canaliculi/canalicular system?

No; There is a calcified bone matric, collagen fibers

What are the four man cell types of one?

Osteoblasts, Osteocytes, Osteoclasts, Osteoprogenitor cells

What do osteoblasts do?

Secrete extracellular matrix (unminneralized bone)

In osteoblasts, what is made up of collagen and ground substances ?

Osteoids

When do osteoblasts become osteocytes?

When osteoblasts are embedded in matrix/ get surrounded by new bone; enter “maintenance mode”

Osteocytes

Found in lacunas; Mature cells, majority of population

Osteoclasts Dedf

Large, multinucleated; Reabsorption of bone

Osteoprogenitor Cells Def

Stem cells that produce osteoblasts

Osteoblast origination

Originate in marrow; Arise from stell cell line that produces fibroblast/fibrocyte, chondroblast/chondrocyte

What control calcium and mineral deposition?

Osteoblasts control calcium and mineral deposition

Old Osteoblasts are called…

Lining cells

What do lining cells (old osteoblasts) do?

Regulate passage of calcium in and out of bone; Response to hormones by making special proteins that activate the osteoclats

Are osteoblasts and osteocytes essentially the same cell?

Yes, jut in two different physiologic states

How can osteocytes help bone repair?

Senses pressures or cracks in the bone and help to direct where osteoclasts will dissolve the bone/remodel

Why do osteoclasts secrete hydrogen into the extracellular space?

To solubilize the mineralized matrix (lowers pH, dissolves the mineral matrix)

For what purposes do osteoclasts resorption release calcium and phosphorus from the mineralized matrix into the circulation for other purpose?

Disease, dietary deficiencies, metabolic disorders, etc.

Somatotropin Def

Growth hormone; Secreted from the anterior pitutiary

Parathyroid hormone def

Secreted by the parathyroid; Stimulates reabsorption of bone and release of calcium into the blood stream

Vitamin D

needed for absorption of calcium from the diet by the digestive system; Vitamin D deficiency= metabolic bone disease