16 Peer Pointers

Bone Markings
Bones have distinct markings that help you
determine its name. See the guide below

Meatus– canal through bone
Process– bony projection
Sinus– open space
Foramen– hole
Fissure– slit like opening
Head– large rounded end of bone
Neck– connects to head of bone
Tubercle– small round projection
Trochanter– large, round projection
Sulcus– narrow groove
Tuberosity– rough projection
Diaphysis– shaft
Epiphysis– expanded ends
Trochlea– smooth, grooved process
Condyle– smooth, round process
Facet– small, flat surface
Crest– prominent ridge
Fossa– shallow depression
Line– ridge
Spine– pointed process
Ramus– makes an angle

Bone Cells and Hormones

There are four types of bone cells:

Osteogenic, Osteoblasts, Osteocytes, and Osteoclasts.

Osteogenic bone cells are the Genesis (beginning) of bone formation. They are stem cells, which are unspecialized cells. They don’t have any specific
functions until they mature.

OsteoBlasts Build Bone. They help the bones to get larger in size and
diameter. They absorb calcium from the bloodstream in order to do this.

Osteocytes “Sigh” because they are more mature than the rest of the bone cells. They typically develop during bone formation.

OsteoClasts Cancel bone. They chew up the saved calcium within the bone, and calcium is released into the blood stream.

Calcitonin: tone it down!

When Calcium levels are too high, Calcitonin tells Osteoblasts to absorb calcium out of the bloodstream. As Osteoblasts use up calcium, the Ca2+ levels in blood decrease.

Parathyroid Hormone: pump it up!

When calcium levels are too low, PTH Hormone tells Osteoclasts to start breaking up parts of bone where calcium is stored. As bone is broken down by Osteoclasts, calcium is released back into the blood stream.