A&P Chapter 6: Bone Tissue and the Skeletal System

Stimulates absorption of calcium and phosphate from digestive tract

calcitriol

Inhibits osteoclast activity and stimulates calcium uptake by bones

calcitonin

Runs down the center of each osteon and contains blood vessels, nerves, and lymphatic vessels

central canal

A fracture in which the skin remains intact

closed

When a bone is manipulated and set into its natural position without surgery

closed reduction

Growth in diameter can continue even after longitudinal growth ceases

appositional growth

The spongy bone and medullary cavity receive nourishment from _____ that pass through the compact bone

arteries

A thin layer of cartilage that reduces friction and acts as a shock absorber

articular cartilage

Where two bones come together

articulation

Three general classes of bone markings

articulations, projections, holes

A hard, dense connective tissue that forms most of the adult skeleton

bone

The _______ ___________ acts as a reservoir for a number of minerals important to the functioning of the body, especially calcium and potassium

bone matrix

The process in which matrix is resorbed on one surface of the bone and deposited on another is known as _______ ______

bone modeling

_______ facilitate movement by serving as points of attachments for muscles

bones

Most abundant mineral in bone and the most abundant mineral in the human body

calcium

Needed to make calcium phosphate and calcium carbonate, which form the hydroxyapatite crystals that give bone its hardness

calcium

The body deposits _____ in the bones when blood levels get too high and it releases ______ when blood levels drop too low (same word in both blanks)

calcium

_________ cannot be absorbed from the small intestine without vitamin D

calcium

______ ______ are essential for muscle contractions and controlling the flow of other ions involved in the transmission of nerve impulses

calcium ions

A semi-rigid form of connective tissue; provides flexibility and smooth surfaces for movement

cartilage

________ serves as a template to be completely replaced by new bone

cartilage

_________ does not become bone

cartilage

Several breaks result in many small pieces between two large segments

comminuted

Found under the periosteum and in the diaphyses of long bones, where it provides strength and protection

compact bone

The walls of the diaphysis are composed of hard, dense ______ _________

compact bone

________ ________ is dense so that it can withstand compressive forces, while ______ ______ has open spaces and supports shifts in weight distribution

compact bone, spongy bone

The tubular shaft that runs between the proximal and distal end of the bone

diaphysis

Flat bones consist of a layer of ______ (spongy bone) lined on either side by a layer of bone

dipole

Bone develops by replacing hyaline cartilage

endochondral ossiciation

Lines the medullary cavity and is where bone growth, repair and remodeling occur

endosteum

A layer of hyaline (transparent) cartilage in a growing bone AKA the growth plate

epiphyseal plate

On the ________ side of the epiphyseal plate, cartilage is formed. On the _____ side, cartilage is ossified

epiphyseal, diaphyseal

The wider section at each end of the bone and is filed with spongy bone

epiphysis

Intramembranous ossification begins during _______ _______

fetal development

-Typically thin and curved -Cranial bones, scapulae, sternum -Serves as point of attachment for muscles and often protect internal organs

flat bones

The last bones to ossify via intamembranous ossification are the _______ _______ ___ _____ ______

flat bones of the face

A broken bone

fracture

People who exercise regularly have _______ bone density then those who are more sedentary

greater

A partial fracture in which only one side of the bone is broken

greenstick

The most apparent functions of the skeletal system are the _____ ________- those visible by observation

gross functions

Increases length of long bones, enhances mineralization, and improves bone density

growth hormones

An opening or groove in the bone that allows blood vessels and nerves to enter the bone

holes

Controls the rate of growth

hormones

________ crystals give bones their hardness and strength while the _________ fibers give them flexibility so they aren't brittle

hydroxyapatite, collagen

-A condition characterized by abnormally high levels of calcium -Results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion and coma

hypercalcemia

-A condition characterized by abnormally low levels of calcium -Results in blood having difficulty coagulating, heart may skip beats or stop beating, muscles have a difficult time contracting, nerves may have difficulty functioning, bones may become brittle

hypocalcemia

One fragment is driven into the other, usually as a result of compression

impacted

The ______ and ______ structure of bone will change as stress increases or decreases so that bone is an ideal size and weight for the amount of activity it endures

internal, external

__________ ________ develops directly from sheets of mesenchymal (undifferentiated) connective tissue

intramembranous ossification

Complex shape -Vertebrae and facial bones -Protects internal organs

irregular bones

-Cylindrical in shape, longer that it is wide -Arms, legs, finger, toes -Function as levers; move when muscles contract

long bones

Five types of bones

long, short, flat, irregular, sesamiod

Structural component of bone (2)

magnesium, fluoride

As more ______ is produced, the chondrocytes in the center of the cartilaginous model grow in size

matrix

________ stress stimulates the deposition of mineral salts and collagen fibers

mechanical

Hollow region in the diaphysis that is filled with yellow marrow

medullary cavity

Break occurs at an angle that is not 90 degrees

oblique

Reduces inflammation that may interfere with osteoblast function

omega 3 fatty acids

A fracture in which at least one end of the broken bone tears through the skin; carries a high risk of infection

open

Requires surgery to expose the fracture and reset the bone

open reduction

Early osteoblasts appear in a cluster called an _____ ______

ossification center

-Responsible for forming new bone -Found in growing portions of the bone, including the periosteum and endosteum -Not mitotic -Synthesis and secrete the collagen matrix and calcium salts

osteoblasts

Four types of bone cells

osteoblasts, osteocytes, osteogenic cells, osteoclasts

-Responsible for bone resorption, or breakdown -Found on bone surfaces and at sites of old, injured, or unneeded bone -Multinucleated -Originate from monocytes and macrophages

osteoclasts

-The primary cell of mature bone and is the most common type of cone cell -Entrapped in a matrix -Not mitotic -Can communicate to each other through the canaliculi

osteocytes

Located inside spaces called lacunae

osteocytes

-Develop into osetoblasts -Undifferentiated and with high mitotic activity and they are the only bone cells that divide -Found in the deep layers of the periosteum and the marrow

osteogenic cells

The microscopic structural unit of compact bone

osteon

Stimulates osteoclast proliferation and resorption of bone by osteoclasts; promotes reabsorption of calcium by kidney tubules; indirectly increases calcium absorption by small intestine

parathyroid hormone

Membrane that covers cartilage

perichondrium

-_______ contains blood vessels, nerves, and lymphatic vessels that nourish compact bone -Tendons and ligaments attach here

periosteum

The _______ gland secrets growth hormones

pitutary

-Areas of the bone that projects above the bone -Attachment points for tendons and ligaments

projections

(Following the reserve zone) it is the next layer toward the diaphysis and contains stacks of slightly larger chondrocytes

proliferative zone

Red blood cells, white blood cells, and platelets are produced in _________ ____________

red marrow

Where hematopoiesis- the production of red blood cells- takes place

red marrow

______ __________ fills the spaces in the spongy bone

red marrow

Resorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone to replace that which is resorbed

remodeling

The region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix

reserve zone

-Small and round; embedded in tendons -Patella -Protects tendons from compressive forces

sesamoid bones

promote osteoblastic activity and production of bone matrix; responsible for adolescent growth spurt; promote conversion of epiphyseal plate to epiphyseal line

sex hormones

-Cube like in shape, being approximately equal in length, width, and thickness -Tarsals and carpals -Provide stability and support as well as some limited motion

short bones

The following are functions of what system? -supports the body -facilitates movement -protects internal organs -produces blood cells -stores and releases minerals and fats

skeletal

Bone segments are pulled apart as a result of a twisting motion

spiral

When blood levels of calcium get too high, the ______ gland is stimulated to release calcitonin

thyroid

A hormone secreted by the thyroid

thyroxine

Stimulates bone growth and promotes synthesis of bone matrix

thyroxine

In spongy bone, lacunae and osteocytes are found in a lattice-like network of matrix spikes called ________

trabeculae

Occurs straight across the long axis of the bone

transverse

Needed for calcium absorption

vitamin D

_________ is not found naturally in many foods

vitamin D

Support bone mineralization; may have synergistic effect with vitamin D

vitamin K

Two types of bone marrow

yellow and red

Contains adipose tissue; the triglycerides stored in the adipocytes of the tissue can serve as a source of energy

yellow marrow

Most of the chondrocytes in this zone are dead because the matrix around them has calcified (zone closest to the diaphysis)

zone of calcified matrix

Chondrocytes are older and larger than those in the proliferative zone

zone of mautration and hypertrophy