Week 4-Skeletal systems and joints
In the bone matrix, osteoblast become what?
Osteocytes
Relatively inactive bone cells that help to maintain the ECM are
Osteocytes
Which of the following is not present in the central canals of osteons?
Osteocytes
Stem cells that can diffrenciate into osteoblast are called___________Cells.
Osteogenic
Cells that develop into osteoblasts are
Osteogenic cells
Explain the anatomical features, locations and possible movements for each of the six structural types of synovial joints.
1. Plane joint - intercarpal joint 2. Hinge joint - elbow joint 3. Pivot joint - proximal radioulnar joint 4. Condyloid joint - metacarpophalangeal joint 5. Saddle joint - Carpometacarpal (joint of thumb) 6. Ball - and- socket - shoulder joint
What best describes the structure of a synovial joint?
A fluid filled cavity is found between the articulating bones
While warming up for gym class, Sheila performed a set of jumping jacks. This action involves
Abduction and adduction
What type of bone growth do you think a 40-year-old male experiences?
Appositional growth
Why is articular cartilage necessary for long bones?
Articular Cartilage allows bones to rub together with reduce friction at joints
In the epiphyseal plate, cartilage grows:
By pushing the epiphysis away from the diaphysis
Which hormone, produced by the thyroid gland, works opposite to para thyroid hormone PTH?
Calcitonin
Bone, or osseous, tissue provides protection for our vital organs since the inorganic ground substance is
Calcium and phosphate crystals
Bone growth and remodeling depends on adequate intake of
Calcium, vitamin C, and vitamin K
What canals connect lacunae together
Canaliculi
List and explain the cellular and extracellular components of bone tissue.
Cells - which in bone are called osteoblasts and osteocytes, (osteo - bone). There are also two other cell types: osteoprogenitor cells and osteoclasts. Osteoprogentor cells: Undifferentiated cells that develop into osteoblasts. Osteoblasts Young bone cells that secrete collagen and cartilage to make the bone matrix. Develop into osteocytes. Osteoclasts Bone cells that use lysozymes to reabsorb bone and are important in bone remodeling. Osteocytes Mature bone cells that lays down and maintain bone. They develop from osteoblasts. Extracellular matrix, which is made up of an organic matrix (30%) containing proteoglycans (but less than cartilage), glycosaminoglycans, glycoproteins, osteonectin (anchors bone mineral to collagen) and osteocalcin (calcium binding protein). There are collagen fibres (mostly type I (90%), with some type V). Only 25% of bone is water. Almost 70% of bone is made up of bone mineral called hydroxyapatite. Before the extracellular matrix is calcified, the tissue is called osteoid (bone-like) tissue. When the concentrations of calcium and phosphate ions rise high enough, they are deposited into the extracellular matrix, and the bone calcifies. Impaired calcification (i.e. in diseases such as rickets) leads to higher levels of osteoid tissue than normal. Calcification occurs only in presence of collagen fibres - salts crystallize in the spaces between the fibres, then accumulate around them.
Identify the internal structural components of compact bone and spongy bone
Compact bone-Dense or cortical bone, solid. In long bones, compact bone forms the solid external walls of the bone. The structure enables it to resist the majority of stresses placed on it, which are linear compression and twisting forces. Spongy bone-The inner, honeycomb-like bone or cancellous bone or trabecular bone, is porous, like a sponge, located internally within the epiphyses. It forms a framework of bony struts that allows it to resist forces in many directions and provides a place for the bone marrow to reside. The diaphysis of long bones consist of a very thick layer of compact bone with only scant inner spongy bone surrounding the medullary cavity. Like the diaphysis, the outer parts of the epiphyses are compact bone; however, the interior of the epiphyses consists of abundant spongy bone.
A long bone that is fractured midshaft has damage which part of the bone?
Diaphysis
Which of the following is a functional joint classification?
Diarthrosis
The lining of the medullary cavity is called the
Endosteum
What is not in effect of growth hormone?
Growth hormone Protts the closure of the epiphyseal plate
Appositional growth procedures
Growth in width
Which of the following is the correct progression in the healing of a skeletal fracture?
Hematoma, fibrocartilage callus, bony callus
The type of Cartlidge that forms the embryonic skeleton is what?
Hyaline cartilage
Identify the types of cartilage found in the skeletal system and explain the functions of each.
Hyaline cartilage, fibrocartilage, and elastic cartilage. Hyaline Cartialge: •most abundant cartilages •spherical chondrocytes only fiber type is collagen fibers •Articular Cartilages: cover ends od most bones at movable joints •Costal Cartilages: connect ribs to sternum •Respiratory cartilages: skeleton of the larynx (voicebox) reinforce repiratory passageways •Nasal cartilages: support external nose Elastic Cartilages: EXTERNAL EAR, AND EPIGLOTTIS
And bone, the calcium phosphate forms crystals of
Hydroxyappetite
Calcitonin functions to
Increase bone deposition
The primary center of ossification
Is in the diaphysis
The small, fluid filled cavity occupied by an osteocyte is called
Lacuna
Anosteon is composed of
Layers of bone lamellae surrounding a central canal
Osteoblast probably originate directly from
Mesenchyme cells
The Cartlidge of the epiphyseal plate is organized into zones based upon the process occurring in these regions. Identify the correct sequence of these processes, from the diaphysis end toward the epiphysis
Ossification - calcification - hypertrophy - growth - resting
The cell responsible for secreting the matrix the bone is the
Osteoblast
What cells contribute to the process of calcification during intra-membraneous ossification?
Osteoblasts
Compare and contrast the functions of osteoblasts and osteoclasts during bone growth, repair and remodeling.
Osteoblasts •matrix synthesizing cell responsible for bone growth •Remodeling: deposit matrix Osteoclasts •GROWTH: multinucleate cells locates at sites of bone resorption. when bone breaks down, they rest in a resorption bay and exhibit a distinctive ruffled border which contacts bone. deep plasma membrane foldings increase surface area for enzymatically degrading bones and seal off area •REMODELING: DIG DEPRESSIONS OR GROOVES as they break bone matrix. they seal off bone areas by clinging to it and secreting lysosomal enzymes that digest organic matrix
_________Cells are located in the intercellular layer of the periosteum
Osteoprogenitor
Which of the following does not correctly depict the effects of parathyroid hormone PTH?
PTH decreases blood calcium ion concentration
In a relationship to the diaphysis of a long bone, the osteons are
Parallel
A hormone that increases the activity of osteoclasts is
Parathyroid hormone
Blood is distributed from the surface of a bone to deeper central canal through channels known as
Perforating canals
Correctly order the following steps in the process of endochondral ossification
Perichondrium is invaded by blood vessels, perichondrial cells differentiate into osteogenic cells then into osteoblasts, Osteoblasts build the bone collar on the external surface of the bone, chondrocytes die, in the primary ossification center, osteoblasts replace calcified cartilage with early spongy bone
Classify joints based on the degree of movement allowed and give examples of each classification.
Plane Joint •flat articular surface, gliding Hinge Joint •flexion and extension (cylinder trough) Pivot Joint •sleeve and axle, rotation Condylar Joint •oval articular surfaces flexion and extension, adduction and abduction Saddle Joint •articular surfaces are both concave and convex adduction and abduction, flexion and extension Ball and socket •cup and ball flexion, extension, adduction, abduction, rotation
Which type of synovial joint is the simplest and least mobile?
Plane joint
Elizabeth fell down a flight of stairs. The angle between her right foot and the tibia increased as her toes were bent toward the ground. What movement do you think caused her to enter her foot?
Plantar flexion
What movement would do expect to see you in a pivot joint?
Rotation
What type of bone is adapted to withstand stress is arriving from many directions?
Spongy bone
Which of the following best represents the functional classifications of joints ranging from least movable to most movable
Synarthrosis, amphiarthrosis, diarthrosis
Which of the following is not a functional join classification?
Synovial
Which statement best describes tendon sheeths?
Tendon sheaths protect long tendons as they course over and around synovial joints
How would the removal of hydroxyappetite crystals from the matrix affect the physical properties of a bone?
The bone would be more flexible
Osteoid
The organic part of bone matrix before the hard bone is present
Explain the structural components of a long bone, with emphasis on the region of longitudinal growth.
They grow primarily by elongation of the diaphysis, with an epiphysis at each end of the growing bone. The ends of epiphyses are covered with hyaline cartilage ("articular cartilage"). The longitudinal growth of long bones is a result of endochondral ossification at the epiphyseal plate.
Branching "ribs" of bone present and spongy bone are known as
Trabeculae
Which of the following are not components of an osteon
Trabeculae
Compare and contrast intramembranous and endochondral bone formation.
Two processes result in the formation of normal, healthy bone tissue. Intramembranous ossification is the direct laying of bone into the primitive connective tissue (mesenchyme). This is how the flat bones of the skull and the clavicles are formed. Endochondral ossification involves cartilage as a precursor. Intramembranous ossification: • Formation of bone directly within loose fibrous connective tissue. • The bone forms directly within mesenchyme (i.e. embryonic connective tissue). • Occurs in skull, mandible, most flat bones • Most occurs before birth. Endochondral ossification: • Mesenchyme hyaline cartilage bone. • Mostly after birth • Most of the bones form this way.
What vitamin deficiency causes rickets and children?
Vitamin D
Which dietary requirements for bone health can be made in response to skin exposure to UV light?
Vitamin D
Within the epiphyseal plate, which zone houses actively dividing cartilage cells in their lacunae?
Zone of proliferation
Contrast the remodeling processes of a child (birth to adolescence) and an adult (middle to old age).
during youth, most fractures results from twists or smashes to bone and in old age, they results from thin and weakened bone fracture or small medium sized bones in young adults heal in six to eight weeks, but it takes longer for large, weight bearing bones of elderly people becasue of poorer circulation
Explain the roles of different hormones in bone remodeling and blood calcium levels.
hormones induce epiphyseal closure, ending longitudinal bone growth. excess or deficits results in abnormal skeletal growth
Explain the functions of those structural components in the context of the whole bone organ.
they all help with the support of the bone and the movement of it against other bones