Search results
Results from the WOW.Com Content Network
The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix. Near the surface of the compact bone, the lamellae are arranged parallel to the surface; these are called circumferential lamellae.
HES4 plays a major role in key developmental processes, particularly in the immune system and bone formation. As a member of the basic helix-loop-helix (bHLH) family of transcription factors , HES4 plays a crucial role in T-cell development by responding to Notch1 signaling, which is vital for guiding hematopoietic progenitor cells toward ...
Cancellous bone or spongy bone, [12] [11] also known as trabecular bone, is the internal tissue of the skeletal bone and is an open cell porous network that follows the material properties of biofoams. [13] [14] Cancellous bone has a higher surface-area-to-volume ratio than cortical bone and it is less dense. This makes it weaker and more flexible.
Diagram of a typical long bone showing both cortical (compact) and cancellous (spongy) bone. Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes.
However, the term describes the shape of a bone, not its size, which is relative. Long bones are found in the arms (humerus, ulna, radius) and legs (femur, tibia, fibula), as well as in the fingers (metacarpals, phalanges) and toes (metatarsals, phalanges). Long bones function as levers; they move when muscles contract. [1]
Diameter of canaliculi in human bone is approximately 200 to 900 nm. [1] In bovine tibia diameter of canaliculi was found to vary from 155 to 844 nm (average 426 nm). [ 2 ] In mice humeri it varies from 80 to 710 nm (average 259 nm), while diameter of osteocytic processes varies from 50 to 410 nm (average 104 nm).
Histone H4 is a 102 to 135 amino acid protein which shares a structural motif, known as the histone fold, formed from three a-helices connected by two loops.Histone proteins H3 and H4 bind to form a H3-H4 dimer, two of these H3-H4 dimers combine to form a tetramer.
Histone tails and their function in chromatin formation Histones undergo posttranslational modifications that alter their interaction with DNA and nuclear proteins. The H3 and H4 histones have long tails protruding from the nucleosome , which can be covalently modified at several places.