Introduction to ossification and endochondral ossification
Ossification is the process in which bone remodelling is laying down new bone material by cells called osteoblasts. It is the same with bone tissue formation. In humans this process starts at around 3 month into the foetus’s life, and this only fully completes in late adolescent life. Osteoblasts are bone forming cells and secrete collagen and other substances that form the ground substance of bone.
Endochondral Ossification is where the bone develops by replacing hyaline cartilage. Cartilage does not become bone, instead cartilage serves as a template to be completely new bone. Endochondral Ossification takes much longer than intramembranous ossification. Bones that form via Endochondral …show more content…
Bone starts to develop by replacing hyaline cartilage. Some of the mesenchymal cells separate into chondrocytes (cartilage cells) that form the cartilaginous skeletal predecessor of the bones. However, the mesenchymal cells separate into chondroblasts that harvest cartilage matrix. This cartilage is a flexible semi-solid matrix, and is produced by chondroblasts and is made up of of hyaluronic acid, chondroitin sulphate, collagen fibres, and water. As the matrix surrounds and isolates chondroblasts, they are then called …show more content…
The presence of Acetylcholine causes the depolarisation of the motor end plate which travels throughout the muscle by the transverse tubules, causing Calcium (Ca+) to be released from the sarcoplasmic reticulum.
Step B shows - In the presence of high concentrations of Ca+, the Ca+ binds to Troponin, changing its shape and so moving Tropomyosin from the active site of the Actin. The Myosin filaments can now attach to the Actin, forming a cross-bridge. The breakdown of ATP releases energy which enables the Myosin to pull the Actin filaments inwards and so shortening the muscle. This occurs along the entire length of every myofibril in the muscle cell.
Step C shows - The Myosin detaches from the Actin and the cross-bridge is broken when an ATP molecule binds to the Myosin head. When the ATP is then broken down the Myosin head can again attach to an Actin binding site further along the Actin filament and repeat the 'power stroke'. This repeated pulling of the Actin over the myosin is often known as the ratchet
Ossification is the process in which bone remodelling is laying down new bone material by cells called osteoblasts. It is the same with bone tissue formation. In humans this process starts at around 3 month into the foetus’s life, and this only fully completes in late adolescent life. Osteoblasts are bone forming cells and secrete collagen and other substances that form the ground substance of bone.
Endochondral Ossification is where the bone develops by replacing hyaline cartilage. Cartilage does not become bone, instead cartilage serves as a template to be completely new bone. Endochondral Ossification takes much longer than intramembranous ossification. Bones that form via Endochondral …show more content…
Bone starts to develop by replacing hyaline cartilage. Some of the mesenchymal cells separate into chondrocytes (cartilage cells) that form the cartilaginous skeletal predecessor of the bones. However, the mesenchymal cells separate into chondroblasts that harvest cartilage matrix. This cartilage is a flexible semi-solid matrix, and is produced by chondroblasts and is made up of of hyaluronic acid, chondroitin sulphate, collagen fibres, and water. As the matrix surrounds and isolates chondroblasts, they are then called …show more content…
The presence of Acetylcholine causes the depolarisation of the motor end plate which travels throughout the muscle by the transverse tubules, causing Calcium (Ca+) to be released from the sarcoplasmic reticulum.
Step B shows - In the presence of high concentrations of Ca+, the Ca+ binds to Troponin, changing its shape and so moving Tropomyosin from the active site of the Actin. The Myosin filaments can now attach to the Actin, forming a cross-bridge. The breakdown of ATP releases energy which enables the Myosin to pull the Actin filaments inwards and so shortening the muscle. This occurs along the entire length of every myofibril in the muscle cell.
Step C shows - The Myosin detaches from the Actin and the cross-bridge is broken when an ATP molecule binds to the Myosin head. When the ATP is then broken down the Myosin head can again attach to an Actin binding site further along the Actin filament and repeat the 'power stroke'. This repeated pulling of the Actin over the myosin is often known as the ratchet