Bone (Mace) Flashcards
What are the components of the skeletal system?
Bones and cartilage
What are the types of cartilage?
Hyaline cartilage
Fibrocartilage
Elastic cartilage
Bones are what kind of connective tissue?
Osseous connective tissue
What are the two types of bone tissue?
Compact bone tissue
Spongy bone tissue
What type of connective tissue are bones made out of?
Dense regular connective tissue
What is the function of ligaments?
Anchor bones to bones
What type of connective tissue are tendons made out of?
Dense regular connective tissue
What is the function of tendons?
Anchor muscles to bones
Cartilage is ____ connective tissue
Semi rigid
Cartilage is/ is not more flexible than bone
Is more flexible than bone
What is the semisolid matrix that cartilage is composed of?
Ground substance, collagen, and elastic fibers, but no calcium salt
What do chondroblasts produce?
Matrix
What are the little cavities that chondroblasts surround themselves in and then become trapped in called?
Lacunae
Once enclosed in the lacunae, the chondroblasts are called…
Chondrocytes
What is Perichondrium?
Sheath of dense irregular connective tissue that surrounds elastic and most hyaline cartilage
What does Perichondrium contain a reserve of?
Perichondrium contains a reserve population of chondroblasts that contribute to cartilage growth throughout life
Cartilage is avascular/vascular in its mature state
Avascular
What process brings nutrients and removes wastes in cartilage?
Diffusion
Why does cartilage heal slowly?
Because it is avascular and relies on diffusion to bring nutrients and remove wastes
What is the most common type of cartilage?
Hyaline cartilage
How does hyaline cartilage appear in the matrix?
Glassy appearing
Hyaline cartilage contains invisible…
Fine collagen fibers
Hyaline cartilage is usually covered by…
Perichondrium
What are some locations that hyaline cartilage is found?
Tip of nose Trachea and bronchioles Most of the Larynx Costal cartilage Articular cartilage Epiphyseal plate Fetal skeleton
What type of cartilage contains conspicuous weblike mesh of elastic fibers?
Elastic cartilage
Elastic cartilage is covered with…
Perichondrium
Elastic cartilage provides flexible, elastic, support in the…
Outer ear and epiglottis
Elastic cartilage is/is not associated with bones
Is not
Elastic cartilage has invisible/very visible elastic fibers in the matrix
Very visible elastic fibers in the matrix
What type of cartilage contains large, coarse parallel bundles of collagen fibers?
Fibrocartilage
Fibrocartilage does/ does not have perichondrium
Does not
Where is Fibrocartilage located?
Pubic symphysis
Menisci
Intervertebral discs
What is the function of Fibrocartilage?
Resist compression and absorb shock
What are the general functions of the bone?
Provide structural support Serve as framework for the body Protect many delicate tissues Movement Hemopoiesis Storage of mineral and energy reserves
The rib cage protects the…
Heart and lungs
The cranial bones protect the…
Brain
The vertebrae protect the…
Spinal cord
The pelvis protects the…
Urinary/reproductive organs and terminal end of the GI tract
Bones serve as attachment sites for….
Skeletal muscles, soft tissue, and some organs
The skeletal system serves as a system of…
Levers- muscle contraction exerting pull on the skeleton
The process of blood cell production occurs in…
The red bone marrow
What is hemopoiesis?
The process of blood cell production in the bone marrow
What does the bone marrow contain that forms red and white blood cells and platelets?
Stem cells
What minerals do bones store?
Most of the body’s reserve of calcium and phosphate are stored within the body and then released from bone into the blood as needed
What is stored in yellow bone marrow in the shafts of some adult bones?
Lipids
What is the name for the growth plate?
Epiphyseal plate
Where is the Epiphyseal plate located?
In the metaphysis
What is the metaphysis?
Region of mature bone between the diaphysis and epiphysis
What type of cartilage is the epiphyseal plate made out of?
Thin layer of hyaline cartilage
What population are epiphyseal plates seen in?
Children
Epiphyseal plates provide for…
Continued lengthwise bone growth
In adults, the epiphyseal plate disappears and turns into the…
Epiphyseal line
The epiphyseal line is a remnant of the….
Epiphyseal plate
What is the tough sheath covering the outer surface of the bone called?
Periosteum
What type of connective tissue is periosteum?
Outer fibrous later of dense irregular connective tissue
What are the functions of the periosteum?
Protects bone from surrounding structures
Anchors blood vessels and nerves to the bone’s surface
Attachment site for ligaments and tendons
What does the inner layer of periosteum contain?
Osteoprogenitor cells, osteoblasts, and osteoclasts
What is the function of the endosteum?
Covers all internal surfaces of bone within the medullary cavity
What does the endosteum contain?
Osteoprogenitor cells, osteoblasts, and osteoclasts
The red bone marrow is also called… (2)
Myeloid tissue, hemopoietic tissue
What does the red bone marrow contain?
Reticular connective tissue, immature red blood cells, and fat
Where is red bone marrow located in children?
Spongy bone and in medullary cavities of long bones
Where is red bone marrow located in adults?
Portions of the axial skeleton- flat bones of skull, vertebrae, ribs, sternum, coxae
in proximal epiphyses of humerus and femur
What is the product of red bone marrow degeneration called?
Yellow bone marrow
Yellow bone marrow is a ___ substance
Fatty
Yellow bone marrow may convert back to red bone marrow during severe….
Anemia
Bone tissue is the ___ most abundant connective tissue in the body
2nd
What percentage of human body weight do the bones make up?
12-15%
Bone is/ is not more solid than cartilage
Is more solid than cartilage
Bones provide greater support than cartilage but are less…
Flexible
Bones are composed of ____ and _____ like other connective tissue
Cells, matrix
What are the two types of bone tissue?
Compact bone tissue
Spongy bone tissue
What are the four types of cells in bones?
Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts
What are Osteoprogenitor cells?
Stem cells
What do Osteoprogenitor cells produce?
Cells that mature to become osteoblasts
Where are Osteoprogenitor cells located?
In the periosteum and endosteum
Osteoblasts are positioned on…
Bone surfaces
Osteoblasts synthesize and secrete…
Osteoid
What is osteoid?
Initial semisolid form of bone matrix that later calcifies
Osteoblasts become ____ within the matrix that they produce
Entrapped
What are osteocytes?
Mature bone cells derived from osteoblasts
Osteocytes can/ cannot form matrix
Cannot- they have lost the ability to form matrix
What relationship do osteocytes have with the bone matrix?
Maintain it
What do osteocytes detect?
Mechanical stress on the bone
What might osteocytes trigger?
May trigger deposition of new bone matrix
describe osteoclasts
Large, mulinuclear, phagocytic cells
What are osteoclasts derived from?
Fused bone marrow cells
Where are osteoclasts located?
On bone surface
What are osteoclasts involved in?
Breaking down bone
The matrix of bone tissue is composed of ____ components and ____ components
Organic, inorganic
What is osteoid composed of?
Collagen protein, proteoglycans, glycoproteins
What is the organic component in the matrix of bone tissue?
Osteoid
What gives bone its tensile strength by resisting stretching?
Osteoid
What part of the matrix of bone tissue contributes to bone flexibility?
Osteoid (organic)
What are the inorganic components in the matrix of bone tissue?
Crystals of calcium phosphate called hydroxyapatite
In addition to hydroxyapatite, the inorganic components contained in the matrix of bone tissue include…
Calcium carbonate, sodium, and magnesium ions
Where do the crystals deposit in the matrix of bone tissue?
Around the collagen fibers of the inorganic components
What is the function of the inorganic components in the matrix of bone tissue?
Harden the matrix and account for relative rigidity of bones
The correct proportion of organic to inorganic substances in the matrix of bone tissue…
Is important! Allows for optimal functioning
What does a loss of protein in the matrix of bone tissue result in?
Brittle bones
What does insufficient calcium result in?
Soft bones
What makes up compact bone tissue? (8)
Osteons Central canals Perforating canals Concentric lamellae External circumferential lamellae Internal circumferential lamellae Interstitial lamellae Canaliculi
Osteons are also called…
Haversian systems
Osteons are small, _____ structures
Cylindrical
What is the basic functional and structural unit of mature compact bone?
Osteon
Osteons are oriented to be parallel to ______
Bone diaphysis
The central Canal is a ____ channel
Cylindrical channel
Describe the position of the central canal?
Lies at the center of the osteon and runs parallel to it
What is contained in the central canal?
Blood vessels and nerves
Perforating canals are also called….
Volkmann canals
What is contained in the perforating canals?
Blood vessels and nerves
Perforating canals run perpendicular/ parallel to the central canals?
Perpendicular
Other than housing blood vessels and nerves, what is the function of the Volkmann canals?
Help connect multiple central canals with different osteons
What are the rings of matrix that surround the central canal called?
Concentric lamellae
What are the rings of matrix that run immediately internal to bone periosteum called?
External circumferential lamellae
What are the rings of matrix that run internal to the endosteum?
Internal circumferential lamellae
What are the rings of matrix in between the osteons called?
Interstitial lamellae
What are the tiny interconnecting channels within bone connective tissue called?
Canaliculi
Where do Canaliculi extend from?
Extend from each lacuna, travel through the lamellae
What do Canaliculi connect?
Connect to other lacunae and central Canal
What do Canaliculi house?
Osteocytes projections permitting intercellular contact
What is the function of Canaliculi?
Allow travel of nutrients, minerals, gases, and wastes between blood vessels and osteocytes
There are/there are not osteons in spongy bone tissue?
No osteons
What are trabeculae?
A lattice of rods and plates in spongy bone tissue
The space in between trabeculae is filled with…..
Bone marrow
What is the function of trabecular in spongy bone?
To form a mesh work of crisscrossing bars that provide great resistance to stresses
Which of the following do trabeculae contain... Parallel lamellae Canaliculi connecting lacunae Central canals Perforating canals
Parallel lamellae
Canaliculi connecting lacunae
(They do not contain central canals or perforating canals)
Which of the following do trabeculae not contain... Parallel lamellae Canaliculi connecting lacunae Central canals Perforating canals
They do not contain central canals or perforating canals
What is bone remodeling?
Bone remodeling is a continual process of bone deposition and resorption
Bone remodeling does/ does not continue throughout adulthood
Does continue through adulthood
Where does bone remodeling occur?
Occurs at periosteal and endosteal surfaces surfaces of a bone
Bone remodeling occurs at different rates depending on the locations, the distal part of the femur gets replaced every ______ whereas the diaphysis of the femur_______.
Distal replaces every 4-6 months
Diaphysis of femur is not completely replaced over a lifetime
What percentage of the adult skeleton is replaced yearly?
20%
What is bone remodeling dependent on?
Dependent on the coordinated activities of osteoblasts, osteocytes, and osteoclasts
What is the relative activity of the cells involved in bone remodeling influenced by?
Mechanical stress and the hormones the bones receive
In bone remodeling, where does the mechanical stress result from?
Muscle contraction and gravitational forces (weight bearing exercises)
How is mechanical stress in bone remodeling detected?
Detected by osteocytes
After mechanical stress is detected by osteocytes, where is it communicated to?
Communicated to the osteoblasts
After being communicated to the osteoblasts, what is their role in the bone remodeling process?
Increase the synthesis of osteoid, followed by the deposition of mineral salts
What is the role of growth hormone in bone remodeling?
It stimulates the liver to produce another hormone, somatomedin, both stimulating the growth of cartilage in the epiphyseal plate
What is the role of thyroid hormone in bone remodeling?
Stimulate metabolic rate of osteoblasts
What is the role of calcitonin in bone remodeling?
Stimulates calcium deposition in bone and inhibits osteoclast activity
What is the role of PTH in bone remodeling?
Causes bone loss (bone resorption) by stimulating osteoclast activity
What are the role of the sex hormones, estrogen and testosterone, in bone remodeling?
Stimulates osteoblast activity, stimulate growth of the epiphyseal plate
What is the role of glucocorticoids in bone remodeling?
Increase bone loss, impair growth at the epiphyseal plate in children
What is the role of serotonin in bone remodeling?
Inhibits osteoprogenitor cells from differentiating into osteoblasts when there are chronically high levels
Bone formation begins with…
The secretion of osteoid
Bone formation begins with secretion of osteoid and proceeds with…
Calcification when hydroxyapatite crystals are deposited- calcium and phosphate ions are precipitated out, forming crystals
What is required for enhancing calcium absorption from the GI tract?
Vitamin D
What is required for collagen formation?
Vitamin C
What is required for calcification?
Calcium and phosphate
In bone resorption, bone matrix is destroyed by substances released from _____
Osteoclasts
In bone resorption, what do the lysosomes in osteoclasts release to break down bone?
Proteolytic enzymes
What are calcium and phosphate dissolved by in bone resorption?
Hydrochloric acid
What may occur when blood calcium is low?
Bone resorption
What are the sources of Vitamin D in the Vitamin D pathway?
UV light Dietary intake (milk)
What is the first step in the Vitamin D pathway?
The precursor molecule is converted to Vitamin D3 (cholecalciferol)
What is the other name for Vitamin D3?
Cholecalciferol
What is the second step in the Vitamin D pathway?
Vitamin D3 is converted to calcidiol in the liver (when an OH group is added)
What is the third step in the Vitamin D pathway?
Calcidiol is converted to calcitriol in the kidney when another OH group is added
KNOW Ca regulation vitamin D PTH negative feedback pathway