What is the purpose of lamellae?
What is the purpose of lamellae?
In fishes, gill lamellae are used to increase the surface area between the surface area in contact with the environment to maximize gas exchange (both to attain oxygen and to expel carbon dioxide) between the water and the blood. In fish gills there are two types of lamellae, primary and secondary.
Why fish Cannot live on land?
Fish get the oxygen their bodies need by pumping water over their gills. Gills serve the same purpose as our lungs do. Gills extract oxygen from water and send it into the fish’s blood stream. For this reason, most fish, and other aquatic animals that get oxygen from water, can’t survive on land very long.
Where are lamellae found?
The lamellae are concentrically located around a central canal (haversian canal) which contained blood vessels, nerves, and loose connective tissue. Volkmann’s canals may be seen connecting haversian canals.
What are the rings formed by the osteocytes called?
The osteocytes are arranged in concentric rings of bone matrix called lamellae (little plates), and their processes run in interconnecting canaliculi. The central Haversian canal, and horizontal canals (perforating/Volkmann’s) canals contain blood vessels and nerves from the periosteum.
How is an Osteon formed?
Osteon (Haversian canal) Osteons are cylindrical vascular tunnels formed by an osteoclast-rich tissue. They contain pluripotential precursor cells and endosteum known as the cutting cone. The bone removed by the cutting cone is replaced by osteoblast-rich tissue.
What cells are required to cause the differentiation of cartilage to bone?
First, the mesenchymal cells are commited to become cartilage cells. This committment is caused by paracrine factors that induce the nearby mesodermal cells to express two transcription factors, Pax1 and Scleraxis.
What are the 3 stages of bone development?
The process of bone formation is called osteogenesis or ossification. After progenitor cells form osteoblastic lines, they proceed with three stages of development of cell differentiation, called proliferation, maturation of matrix, and mineralization.
At what age does cartilage turn to bone?
During childhood, as you are growing, the cartilage grows and is slowly replaced by bone, with help from calcium. By the time you are about 25, this process will be complete.
What gives rise to osteoblasts?
5.2. Osteoblasts are mononucleate cuboid cells that are responsible for bone formation. Osteoblasts originate from immature mesenchymal stem cells, which can also differentiate and give rise to chondrocytes, muscle, fat, ligament and tendon cells (Aubin and Triffitt, 2002).
What two things do osteoblasts need to stay alive?
Components that are essential for osteoblast bone formation include mesenchymal stem cells (osteoblast precursor) and blood vessels that supply oxygen and nutrients for bone formation.
What stimulates osteoclast activity?
Osteoclastic activity is stimulated by cytokines such as IL-6 and RANK and inhibited by calcitonin.
What can a deficiency of growth hormone during bone?
GH deficiency severely limits bone growth and hence the accumulation of bone mass.
What determines bone remodeling?
The regulation of bone remodeling is both systemic and local. The major systemic regulators include parathyroid hormone (PTH), calcitriol, and other hormones such as growth hormone, glucocorticoids, thyroid hormones, and sex hormones.
Which vertebrae does not have a body?
C1 vertebra
What is the difference between a facet and a process?
The articular processes or zygapophyses (Greek ζυγον = “yoke” (because it links two vertebrae) + απο = “away” + φυσις = “process”) of a vertebra are projections of the vertebra that serve the purpose of fitting with an adjacent vertebra. The actual region of contact is called the articular facet.
Which part of the body does it affect when a disc is ruptured?
Disc ruptures in the low back typically affect the sciatic nerve roots that exit the spine on either side of the discs. The sciatic nerves pass through the buttock, down the leg, and into the foot. That’s why you feel pain, tingling, and numbness in those locations.
Which part of the vertebral column receives the most stress by bearing the most weight of the body?
lumbar region
Which bone is not weight bearing?
The fibula is the slender bone of the lateral side of the leg and does not bear weight.
Which is the largest longest and strongest bone in the body?
femur bone
What is the suture that connects the two parietal bones together?
Lambdoid suture: the suture between the two parietal bones and the occipital bone.