Question

The bone cell responsible for breaking down bone tissue is the _______, while the bone cell that produces new bone tissue is the _______. a. osteoclast, osteoblast b. osteocyte, osteoclast c. osteoblast, osteocyte d. osteocyte, osteoblast e. osteoclast, osteocyte

Short answer

The bone cell responsible for breaking down bone tissue is the osteoclast, while the bone cell that produces new bone tissue is the osteoblast. Thus, the correct answer is (a) osteoclast, osteoblast.

Step-by-step solution

Identify functions of each bone cell type

First, let's recall the functions of each bone cell type: - Osteoclasts: these cells are responsible for breaking down bone tissue. - Osteoblasts: these cells are involved in the production of new bone tissue. - Osteocytes: these cells are matured and maintain the bone tissue.

Match the cell types with their functions in the given sentence

The sentence states that the first blank should be filled with the bone cell responsible for breaking down bone tissue, and the second blank should be filled with the bone cell that produces new bone tissue. From our understanding of each bone cell type, we know that: - The cell responsible for breaking down bone tissue is the osteoclast. - The cell that produces new bone tissue is the osteoblast.

Choose the correct option from the given choices

Now that we have matched the cell types with their functions, we can look for the option that has the correct combination: a. osteoclast, osteoblast b. osteocyte, osteoclast c. osteoblast, osteocyte d. osteocyte, osteoblast e. osteoclast, osteocyte The correct option is (a) osteoclast, osteoblast, as these are the bone cells responsible for breaking down bone tissue and producing new bone tissue, respectively.

Key concepts

Osteoclast

Osteoclasts play a crucial role in bone health. They are large, multinucleated cells that break down bone tissue, a process known as bone resorption. This happens when osteoclasts dissolve the mineral matrix of the bones, releasing calcium and phosphate into the blood. This process is essential for maintaining healthy levels of these minerals throughout the body, playing a part in overall metabolic processes.

• Bone resorption by osteoclasts is necessary for bone remodeling, a continuous cycle where old bone is removed to make way for new bone.
• This is important because it helps repair micro-damages to the skeleton, which can naturally occur from everyday stress.
• Osteoclasts are activated in response to signals by hormones such as parathyroid hormone (PTH), which increases when blood calcium levels drop.

Without proper function of osteoclasts, bones can either become overly dense or fragile, leading to various medical conditions. Understanding these cells helps shine a light on diseases like osteoporosis, where an imbalance between bone resorption and formation occurs.

Osteoblast

Osteoblasts are key players in bone formation. They are derived from precursor cells known as mesenchymal stem cells and are responsible for the production and secretion of the bone matrix. During bone formation, osteoblasts lay down new layers of bone tissue using proteins and minerals such as collagen and calcium.

• Osteoblasts initiate the process of mineralization, creating a rigid structure that strengthens and supports the skeleton.
• These cells orchestrate the deposition of organic components, which are vital to give bones their strength and flexibility.
• The activity of osteoblasts can be influenced by hormones like osteocalcin, vitamin D, and growth factors, supporting bone development and maintenance.

Upon fulfilling their role, osteoblasts can become embedded in the bone matrix they've created, transitioning into osteocytes. This cellular transformation marks their reduced ability to lay down new bone but enhances their role in maintaining bone tissue integrity.

Osteocyte

Osteocytes are mature bone cells formed when osteoblasts become trapped within the matrix they secrete. These cells reside within small cavities in the bone called lacunae and extend long, slender projections through tiny channels called canaliculi.

• The primary function of osteocytes is to maintain healthy bone tissue by participating in nutrient exchange and signaling for bone repair when needed.
• They help regulate the balance of minerals in and out of the bone, ensuring that bone remodeling occurs efficiently.
• Osteocytes have a sensory function, detecting mechanical strain on the bone and sending signals to osteoblasts and osteoclasts to remodel the bone accordingly.

Given their central position within the bone structure, osteocytes act as a communication hub, coordinating between the bone surface and its interior to maintain bone homeostasis. They are a testament to the complex and adaptive nature of bone as a living tissue.