Bones Exam 2 Flashcards
stem cell overview slide that details cellular development giving rise to cartilage,
fibers (collagen) and bone
Stem cells that give rise to cartilage, collagen fibers, and bone are primarily called “mesenchymal stem cells” (MSCs),…connective tissues, including cartilage, bone, and the cells responsible for producing collagen fibers (fibroblasts), through a process called “lineage commitment”
What is ossification?
the process of laying down new bone material by cells named osteoblasts…bone remodeling
What is osteoid?
the unmineralized, organic portion of the bone matrix that forms prior to the maturation of bone tissue.
What are the two types of ossification?
Endochondral and Intramembranous
Type of bones in which ossification occurs
Intramembranous ossification
This process directly converts mesenchymal tissue into bone, and is responsible for the formation of flat bones like the skull and clavicle.
Endochondral ossification
This process involves cartilage as an intermediate, formation of long bones, short bones, and the ends of irregular and flat bones. It also accounts for bone elongation after birth, which is accomplished by the epiphyseal plate, or cartilage growth plate.
Type of tissue in which ossification centers form
the periosteum, which is a tissue that surrounds the cartilage of the diaphysis. The primary ossification center forms in the periosteal collar,
Number of ossification centers
At birth: There are about 450 ossification centers.
206 bones at adult
how is bone so strong? What makes it rigid, but not brittle?
The minerals, including calcium and phosphorous from the blood, that crystallize. protein, collagen, and minerals, especially calcium
What is red bone marrow? Yellow bone marrow? (what do they store/produce?)
stem cells make red bone marrow, which creates blood cells and platelets for your blood. Yellow bone marrow is fat and stem cells that produce bone and cartilage in your body
▪ What are the functions of cartilage?
Cartilage is a flexible connective tissue
Protecting bones
Supporting structure
Absorbing shock
Controlling joint alignment
▪ What cells produce cartilage matrix? Fibers? Cells that manage cartilage?
chondrocytes:
Function:
They secrete the extracellular matrix (ECM) components of cartilage, including collagen fibers and proteoglycans.
Location: lacunae within the cartilage matrix.
Cartilage management:
Chondrocytes are “manager” cells of cartilage as they actively maintain the tissue by producing and regulating the ECM components.
▪ What types of growth are seen in cartilage?
Appositional growth:
New chondroblasts differentiate from the perichondrium (the outer layer of cartilage).
These chondroblasts produce new cartilage matrix, adding layers to the existing cartilage surface.
Interstitial growth:
Existing chondrocytes within the cartilage matrix undergo cell division.
The newly formed chondrocytes secrete new cartilage matrix, causing the cartilage to expand from the inside.
▪ What are the functions of the four types of bone cells?
Osteoblasts
Create new bone by synthesizing bone matrix and depositing minerals. produce hormones & mineralization.
Osteocytes
Help maintain bone structure by regulating mineral concentration and sensing mechanical stress. control osteoblast and osteoclast activity.
Osteoclasts
Break down and reabsorb bone tissue, releasing minerals like calcium and phosphate into the bloodstream. remodeling and the body’s metabolic needs.
Bone lining cells
These cells help maintain the bone matrix.
▪ Describe the microscopic anatomy of compact bone
made up of tightly packed osteons, or central canals
▪ Draw the microscopic anatomy of compact bone
draw
▪ Describe the microscopic anatomy of spongy bone
Trabeculae
A lattice-like network of bony spicules that form a mesh structure. The osteocytes, are housed in lacunae.
Spaces
The spaces between the trabeculae are often filled with red bone marrow, which contains hematopoietic stem cells.
▪ Compare and contrast compact vs spongy bone
Structure
Compact bone is made up of cylindrical units called osteons, while spongy bone is made up of plates and bars of bone called trabeculae.
Location
Compact bone is found in the outer layer of bones, while spongy bone is found in the ends of bones
Function
Compact bone provides strength and protection, while spongy bone provides structural support and flexibility
▪ How does bone density change throughout life? Remodeling? Turnover?
Bone density generally increases during childhood and adolescence, reaching peak mass around the late 20s, declines with age due to a process called bone remodeling, where the rate of bone breakdown (resorption) starts to exceed the rate of new bone formation. leading loss of bone mass,
▪ What do vitamins A, C, D do?
Vitamin A
supports eye health, bone growth, and reproduction. maintain healthy skin, mucous membranes, and soft tissue.
Vitamin C
antioxidant that helps protect cells and promotes healthy teeth and gums. absorb iron and heal wounds.
Vitamin D
absorb calcium and mineralize bones. It’s also known as the “sunshine vitamin”
▪ What do growth hormone, thyroid hormone, estrogen and testosterone do?
Growth hormone:
Primarily responsible for physical growth in children, promoting bone and muscle development, and maintaining muscle mass in adults; released by pituitary gland.
Thyroid hormone:
Regulates metabolism, impacting functions like body temperature, heart rate, and energy usage; produced by thyroid gland.
Estrogen:
female sex hormone, crucial for menstrual cycle regulation, and bone health.
Testosterone:
male sex hormone, responsible for male sexual development, muscle mass, bone density, and sex drive.
▪ Describe the factors that affect bone homeostasis(calcium levels, calcitonin & PTH)
PTH
Released by the parathyroid glands in response to low serum calcium levels, PTH increases calcium levels by stimulating bone reabsorption and increasing calcium reabsorption in the kidneys.
Calcitonin
Released by the thyroid gland in response to high serum calcium levels, calcitonin decreases calcium levels by inhibiting bone breakdown and increasing urinary calcium excretion.
Vitamin D
▪ Describe the epiphyseal plate morphology and pattern of growth
growth plate, is a thin layer of cartilage at the ends of long bones that’s responsible for bone growth.
Structure
made of hyaline cartilage and is divided into three zones: resting, proliferative, and hypertrophic.
Growth
growth is controlled by endocrine, autocrine, and paracrine factors. Chondrocytes in the plate differentiate and proliferate, eventually transforming into bone.
Maturation
The epiphyseal plate matures during childhood, and its width decreases.
Closure
The epiphyseal plate closes, or fuses, when it’s replaced by bone, which usually happens after puberty.
▪ Know types of fractures & process of bone fracture healing (know steps for order Q?)
open and closed, partial and complete, and displaced and non-displaced.
Soft callus formation
Cells that form cartilage and bone differentiate and create a soft callus that bridges the fracture gap.
2. Granulation tissue formation
Blood vessels and fibroblasts form granulation tissue, which provides oxygen and nutrients for bone healing
▪ Describe the effects of aging on bone
Bone loss: Bones lose density and mass, which can lead to osteoporosis
Brittle bones:
Bone mineral loss:
Bone shrinkage
Bone marrow fat accumulation
▪ Compare and contrast osteopenia and osteoporosis
Osteopenia is a decrease in bone mineral density (BMD) that’s not yet severe enough to be classified as osteoporosis. Osteoporosis is a more advanced stage of bone loss that’s characterized by a significant decrease in BMD.
▪ Know about the paranasal sinuses (3 important functions?)
Lightening the weight of the skull
Protecting vital structures in the event of facial trauma
Insulating sensitive structures from rapid temperature fluctuations in the nose
Playing a role in immunological defense
Producing nitric oxide, which helps with oxygen uptake
▪ Orbital complex (space for eye, eye muscles, nerves, blood vessels)
Inner orbital complexes: The central metal atom uses inner shell d orbitals for hybridization.
Outer orbital complexes: The central metal atom uses outermost shell d orbitals for hybridization
▪ Ribs (difference between true and false, #) & Pelvis (male / female differences)
24 ribs
True ribs
The first seven pairs of ribs are true ribs, and they attach to the sternum protect the heart and lungs,
False ribs
The eighth, ninth, and tenth pairs of ribs are false ribs, and they attach to the seventh rib by cartilage. False ribs protect the stomach, spleen, and kidneys.
▪ OTHER bones associated with the skull
hyoid-swallowing,
ossicles(ears)
M,I,S-hearing(hearing loss)
▪ The vertebral column (# of each type),
The vertebral column is made up of 33 vertebrae, divided into five regions: cervical, thoracic, lumbar, sacral, and coccygeal
the arches of the feet
distributing body weight evenly, absorbing shock during walking and running, and providing stability and balance
the fetal skull (fontanelles and soft tissue allow for what
and when?
skull to pass through birth canal
