Apologia The Human Body Module 4

osteoblast

a bone-forming cell

osteocyte

a mature bone cell surrounded by bone matrix

osteoclast

a large, multinucleated cell that breaks breaks down bone

hematoma

a localized mass of blood that is confined to an organ or some definable space

callus

a mass of tissue that connects the ends of a broken bone

anatomical position

the position acquired when one stands erect with the feet facing forward, the upper limbs hanging at the sides, and the palms facing forward with the thumbs to the outside

collagen and hydroxyapatite

two principal agents in bone matrix

collagen

gives bones some flexibility and tensile strength

hydroxyapatite

gives bones their hardness

osteocyte

what kind of bone cell is completely surrounded by bone matrix

osteoclast

bone cell that has more that one nucleus

cancellous bone tissue

bone tissue that has no osteons

cancellous bone tissue

bone tissue that contains trabeculae

red bone marrow

found in the spaces between the trabeculae

concentric lamellae

term for the layers of tissue that form an osteon

interstitial lamellae

term for the layers of tissue between osteons

canaliculi

the extensions of osteocytes which allow the cells in bone tissue to communicate with one another

to turn cancellous bone into compact bone, to increase and decrease in mass based on the stress they experience, to re-shape the bone as needed, to repair broken bones, to replace worn collagen or hydroxyapatite, and to regulate the calcium levels in the body

why bone tissue must continually be remodeled

cartilage is ossified at the same rate in which it is added

why the epiphyseal plate does not thicken as a bone grows

the side with the diaphysis

which side does the tissue ossify

appositional bone growth

when osteoblasts lay new bone tissue on top of old bone tissue

hematoma forms, callus forms, callus is ossified, external callus is removed by osteoclasts and cancellous bone remodeled as needed

the process in which a bone is repaired

helps hold the broken pieces of bone together

purpose of an external callus

ossifies to become new bone

purpose of an internal callus

thyroid gland

secretes calcitonin

parathyroid gland

secretes PTH

decreases osteoclast activity

effect of calcitonin on bone cells

increases osteoclast activity

effect of PTH on bone cells

high

if a person has large levels of calcitonin in his blood, does he have low or high calcium levels

anterior pituitary gland

gland that secretes human growth hormone

stimulates bone growth by increasing osteoblast activity

the effect of HGH on bone tissue

increase osteoblast activity which stimulates bone growth; stimulate ossification of the epiphyseal plates which halts bone growth

effect of the sex hormones on bone growth

fibrous joints, cartilaginous joints, and synovial joints

three major types of joints in the body

synovial joints

type of joint associated with the most movement in the skeleton

cushions the ends of the bones with a "hard plastic" finish

purpose of the articular cartilage in a synovial joint

lubricates the joint

purpose of the synovial fluid in a synovial joint

synovial membrane

produces synovial fluid

ball and socket, ellipsoid, saddle, hinge, pivot, and gliding

six major types of synovial joints

plantar flexion

motion in which a ballet dancer stands on her tiptoes

extension

motion in which a person doing push-ups lifts his body from a position where his elbows are bent so that his body is close to the ground to where his elbows are straightened

circumduction

motion where a person who is standing on one leg begins to twirl the leg that is in the air in circles

pronation

motion in which a person is holding his palms up and then turns his hands so that the palms point down

abduction

motion in which a person holding his arms down at his sides lifts them both up so that they are horizontal to the ground pointing to each side