The bo ne is a conne ct ive tissue. •
The bo dy is most ly made ou t of long bones. •
Bones are t he pr ima rily skele tal structure that supports mus cle s and give s shape to the body. •
Compact bone is superficial to the spongy b one . •
Spongy bone is de ep to t he compac t bone. •
Hydroxyapatite : is the mat ri x fou nd in b one t issue and i t is a se cre tor y matrix. And the cells are called •
osteocyte s.
Shapes o f bones:
Flat bone s: Sternum, ribs, scapula, skull, and hip bones. 1.
Long bones : th e length of long bones is greater th an the wid th. They h ave round ends and the y are the 2.
mos t important bones in bo dy movement. Long bones are dense hard bone s that provide s tre ngt h,
st ruc tu re, and mobilit y. Examples: limbs, hume rus, radius, ulna of the arm & forearm , femur, ti bia, fibula o f
the thigh & leg.
Short bones: the wris ts and ankles h ave abou t 30 short bones (c arp als a nd tarsal s bones). Th ey are equa l in 3.
length and width . Examples: car pals, tars als, patella .
Sesamoid bone: is a small bone em bedded in a te ndon. 4.
Irregular bones: the verte brae, facial bones, the sphenoid, and e thmoid bo nes of the skull. 5.
Types of bones:
Compact bone & Spongy bone: are t wo basic structural bone types. The y mak e up th e long bone s in the body. The
mai n dif ference bet ween spong y and compact bones is the ir s tr uct ure and funct ion .
Types of bone cells: all found in the osseous t issue (bone tissue)
Oste oge nic cells: they de velop in to os teoblasts. They are located in the deep l ayers of the periosteum and 1.
the marrow.
Oste oblasts cel ls: they produce bone mat ri x, th ey form the bone mat rix. They are located in the growing 2.
portions of bone, including per ios teum and endos teum
Oste ocy tes cells: they main tai n mineral concentratio n of matrix (bone t issue). They are e nt rappe d in the 3.
mat ri x. The se cell s are fo und in mat ure bo nes.
Oste oclasts cells: t hey do bone resorp tio n. They are located at t he bo ne surfaces and at si tes of old, injured, 4.
or unneeded bone.
Compact bone : 1.
they are pre sent in the o ute r layer of long bones. •
Oste on ( or h aversian syste m) is the functional unit o f compact b one . •
Oste ocy tes occupy small chambers cal led lacunae, t hat create concen tr ic circles around ce nt ral c anals in •
bones.
Lac unae is whe re the oste ocy tes live •
we have osteocy te and lacunae a rranged in •
concen tr ic lame llae around the cen tral canal.
Can aliculi are can als that connect the osteocy tes . •
