EXSC223 Spongy Bone and Marrow

spongy bone is present in what kinds of bone

all kinds

trabecular bone is also a name for _____________

spongy bone. You should be familiar with this term because the bone that is present is known as trabecular

trabeculae are

short struts comprising the spongy bone

describe the structural makeup of spongy bone

Only a few cells thick, trabeculae contain irregularly arranged
lamellae and osteocytes interconnected by canaliculi. No osteons are present.

how does spongy bone get nutrients?

Nutrients reach the osteocytes of spongy bone by diffusing through the canaliculi from capillaries in the endosteum surrounding the trabeculae.

what's the difference in the structure of compact vs spongy bone?

the lamellae of spongy bone is not organized into osteons, so the collagen is not organized in the same way as compact bone

the structure of spongy bone seems random, but describe why it's actually not

it distributes an area of stress from one place to another via the trabeculae so that less force will occur to the opposing side

in load bearing areas like your femur, the trabeculae will __________________

adapt to distribute the stress better based on the bone's use

what is wrapped around the trabeculae?

endosteum

________________ is the functional unit of spongy bone

trabeculae

the difference spongy vs compact bone is in how the ______ is organized

how the collagen is organized

in flat bone, there is no ___________ or ______________

diaphysis or epiphyses

name the two kinds of marrow

red marrow and yellow marrow

red bone marrow is also referred to as ____________________

hematopoietic stem tissue

red marrow is where we produce our _________________

erythrocytes, leukocytes, and platelets

when you are born, you only have ____________________ marrow

red marrow, NO YELLOW

true or false: red bone marrow is found in all bones of newborns, including the medullary cavity of compact bone

true, red marrow in newborns is found in the medullary cavity of the diaphysis and all areas of spongy bone including epiphyses

yellow marrow is _________

adipose tissue, fat

true or false: there are empty spaces where no marrow is found

false. if red marrow is not present, yellow marrow is. there are no empty spaces

yellow marrow is present in the ___________________

medullary cavity of the diaphysis, and in most of the distal bones (upper and lower appendages)

in adults, red marrow is present in _______________

flat bones (sternum, cranium), and in the heads of the femur and hummerus

true or false: red marrow is found in the proximal areas of the femur and humerus, not the distal parts

true

why do children have higher red blood cells than adults?

because they only have red marrow