Level 2 - Skeletal Development 1 Flashcards
What are the functions of bone?
-support
-protection
-movement
-mineral storage
-hematopoiesis
Blood cell formation is carried out by myeloid tissue (red bone marrow).
In adults the myeloid tissue is found in the epiphyses of certain long bone and in flat bones of the skull, pelvis, sternum, ribs
Hematopoiesis
What are the 5 major types of structural bone?
Long bone (femur)
Short bone (carpal)
Flat bone (scapula)
Irregular bone (vertebrae)
Sesamoid bone (patella)
-Main long shaft of bone
-hollow, cylindrical shape and thick compact bone
-provides strong support without cumbersome weight
Diaphysis
-Both ends of a long bone, made of cancellous bone filled with marrow
-bulbous shaped
-provides attachments for muscles and gives stability to joints
Epiphyses
The zone of growth between the epiphysis and diaphysis during bone development
Metaphysis
Where bone grows
Epiphyseal line
Layer of hyaline cartilage that covers the articular surface of epiphyses
-functions to cushion jolts and blows
Articular cartilage
*Long bone
-dense white fibrous membrane that covers bone
-attached tendons firmly to bones
-contains cells that form and destroy bone
-contains blood vessels important in growth and repair
-contains blood vessels that send branches into bone
-essential for bone cell survival and bone formation
Periosteum (surrounds bone)
*long bone
-tubelike hollow space in the diaphysis
-filled with yellow marrow in adults
-filled with red marrow in kids
Medullary cavity (marrow)
*long bone
Thin, fibrous membrane that lines the medullary cavity of long bones. Also lines the space of spongy bone
Endosteum
*long bone
Cranial flat bones have an internal and external table of compact bone and an inner cancellous region called the:
Diploë (spongy bone in flat bones)
T/F
Spaces inside the cancellous bone of short, flat, irregular and sesamoid bones are filled with red marrow
Ex. Sternum
True
-most distinctive form of connective tissue
-extracellular components are hard and calcified
-rigidity of bone gives it supportive and protective functions
-tensile strength nearly equal to that of cast iron at less than 1/3 the weight
Bone tissue
-extra cellular components are hard and calcified
-rigidity of bone gives it supportive and protective functions
-tensile strength nearly equal to the of cast iron at less that 1/3 of weight
Characteristics of bone tissue
Contains many cylinder-shaped structural units called OSTEONS or HAVERSIAN systems
Compact bone
-surround central (Haversian) canals (containing blood/lymphatic vessels and nerves) that run lengthwise through bone and are connected by transverse (volkmann)
Osteon
Where are living bone cells located?
Osteons
*constitute the structural framework of compact bone
*osteons permit delivery of nutrients and removal of waste products
What are the 3 structures of the lamellae?
-concentric
-interstitial
-circumferential
Lamellae
Cylinder-shaped layers of calcified matrix around central canal
Concentric
Lamellae
Layers of bone matrix between the osteons; leftover from previous osteons
Interstitial
*between tissue
Lamellae
Few layers of bone matrix that surrounds all osteons; run along the outer circumference of a bone and inner circumference (boundary of medullary cavity) of a bone
*surrounds several osteons
Circumferential
What structures make up the osteon?
-lamellae
-lacunae
-canaliculi
-central (osteonal or Haversian) canal
Small spaces containing tissue fluid in which bone cells are located between hard layers of the lamella
*hallow spaces/blue spots on osteon model
Lacunae
Ultra small canals radiating in all directions from the lacunae and connecting them to each other and to the central canal
Canaliculi
*hair like structures, red on osteon model
Extends lengthwise through the Center of each osteon; contains blood vessels and lymphatic vessels and nerves. Nutrients and oxygen move from the central canal through the cancliculi to the lacunae and their bone cells inside
Central (ostenonal or Haversian) canal
T/F
Compact bone, in addition to bone marrow and blood vessels from the periosteum penetrates the bone and then, by way of transverse (Volkmann) canals, connects with vessels in the central canals of osteons
True
T/F
Bone cells are metabolically active and need a blood supply, which comes from the bone marrow in the internal medullary cavity of cancellous bone
True
T/F
Cancellous bone does not have osteons
True
*has trabeculae instead
-nutrients are delivered and waste products removed by diffusion through tiny canaliculi similar to compact bone
Bony branches arranged along lines of stress to enhance the bones strength
Trabeculae
*cancellous bone
Where is spongy bone (traveculae) found?
-between compact bond in:
Flat bones
Irregular bones
Seamus bones
Long bone (inside epiphysis and lining the medullary cavity)
What are the 3 types of bone cells?
-osteoblasts
-osteoclasts
-osteocytes
-bone forming cells found in all bone surfaces
-small cells synthesize and secrete osteons, an important part of the ground substance
Osteoblasts
-giant multinucleated cells
-responsible for active erosion of bone minerals
-contain large numbers of mitochondria and lysosomes
Osteoclasts
T/F
Osteoblasts, osteoclasts, osteocytes are found in both compact and spongy bone
True
-mature non-dividing osteoblasts surrounded by matrix and lying within lacunae
Osteocytes
-type of soft, diffuse connective tissue; called myeloid tissue
-site for production of blood cells
-found in medullary cavity of long bone and in spaces in spongy bone
Bone marrow
What bones in adults still contain red marrow?
Ribs
Vertebrae (bodies)
Humerus
Pelvis
Femur
Scapula
Clavicle
Sternum
T/F
Red marrow can change to yellow marrow during times of decreased blood supply, such as anemia, radiation exposure, disease
True
-found in virtually all bones in an infant or child body
-produces red blood cells
Red marrow
-As individuals age, red marrow is replaced
-marrow cells become saturated with fat and are no longer active in blood cell production
Yellow marrow
T/F
The skeletal system is a storehouse for about 98% of body calcium reserves
True
Osteoblasts remove calcium from blood and lower circulating levels
During bone formation
Osteoclasts release calcium into blood and increase circulating levels
During breakdown of bone
Homeostasis of calcium ion concentration is essential for:
-bone formation, remodelling, repair
-blood clotting
-transmission of nerve impulses
-maintenance of skeletal and cardiac muscle contraction
-primary regulator of calcium homeostasis
-stimulates osteoclasts to initiate breakdown of bone matrix and increase blood calcium levels
-increase renal absorption of calcium from urine
-stimulates vitamin D synthesis
Parathyroid hormone
*mechanisms of calcium homeostasis
-protein hormone produced in thyroid gland
-produced in response to high blood calcium levels
-stimulates bone deposition by osteoblasts
-inhibits osteoclast activity
-far less important than parathyroid hormone
Calcitonin
