Ch 6 Skeletal Flashcards
What bones fuse together after birth?
Frontal of the skull, mandible, pelvic bone, and coccyx
Extra pieces usually found within a suture joint
Sutural bones
Bones embedded in a tendon or a muscle near joint surfaces
Sesamoid bones
Reduced friction between bones
Cartilage
Attach muscles to bones
Tendons
Connect one bone to another bone
Ligaments
Substances (material) surrounding bone cells
Bone matrix
What compound provides weight bearing strength
Hard calcium
What provides flexible strength
Collagen fibers
- Cells that add calcium compounds to bone matrix
- build bone matrix
Osteoblasts
- cells that secret acids and enzymes that dissolve bone matrix
-breaks down bone matrix and calcium ions are released into the bloodstream
Osteoclasts
- cells that support and nourish bone matrix
- mature bone cells
Osteocytes
Forms the hard outer shell of the bones
Compact bone
Concentre rings of bone matrix
Lamellae
Small spaces that contain osteocytes
Lacunae
Contains blood vessels and nerves
Central canal
Tiny passageway between osteocytes and the central canal
Canaliculi
-Forms inside of bone
- spaces are filled with bone marrow
Spongy bone
Needle-like of plates of bone
Trabecuale
Sites of blood cell production
Red marrow
Stores adipose
Yellow marrow
At birth is all bone marrow red or yellow
Red
Where is red marrow found in adults
Flat bones of the skull, vertebrae, ribs, sternum, clavicle, scapula, pelvic bone, and proximal ends of the humerus and femur
Center shaft of a long bone
Diaphysis
What is the diaphysis made up of?
Compact bone
Hollow cavity filled with adipose
Marrow cavity
At the proximal and distal ends of the bone
Epiphysis
What type of bone does the epiphysis contain?
Spongy bone
Covers the epiphysis
Articular cartilage
Tough, fibrous membrane that covers the outer surface of bone
Periosteum
Inner membrane that contains bone cells
Endosteum
Bone formation- replacing other tissues with bone
Ossification
One tissue replaces cartilage- most bones (including long bones) are formed this way
Endochondral ossification
-Bone development within sheets of membranes of fibrous connective tissue
- bones formed this including flat bones of the skull, mandible, and the clavicle
Intramembranous ossification
Deposition of calcium salts
Calcification
Hyaline cartilage forms miniature models of future bones
Cartilage model
- Starts at the outer part of the diaphysis
- chondrocytes in the diaphysis enlarge and the matrix begins to calcify
Bony collar bone formation
- diaphysis is the first place
- new osteoblasts form spongy bone
Primary ossification center
- Epiphyses begin to calcify and fill with spongy bone
- osteoclast begins to break down spongy bone in the diaphysis
Secondary ossification centers
- growth plates made up of hyaline cartilage
- lengthwise growth occurs as chondrocytes divide by mitosis
- cartilage near the diaphysis is replaced with bone as osteoblasts add bone matrix
Epiphysis plate
- remnants of growth plate
- indicates all the cartilage of the epiphyseal plate has been replaced by bone and therefore growth has stopped
Epiphyseal lines
Growth in width of bone
Appositional growth
Give bone weight bearing strength
Calcium and phosphate salts
Needed for collage synthesis
Vitamin C
Stimulates osteoblasts
Vitamin A
Increases calcium absorption from the digestive tract
Vitamin D3
Promotes growth at epiphyseal plate by stimulating chondrocytes and osteoblasts to divide (mitosis)
Growth hormone
Adjusts the activities of GH
Thyroid hormone
- Initially stimulated bone growth
- change the race between chondrocytes and osteoblasts in divide (mitosis)
Estrogen and testosterone
- adjust bone architecture to meet changing mechanical needs
- helps repair micro-damages to bone matrix and prevent accumulation of old bone
Bone remodeling
Break down and remove old/damaged bone matrix
Osteoclast (bone remodeling)
Build and lay down new bone matrix
Osteoblasts (bone remodeling)
Bone in a healthy person will adapt to the loads under which it is placed
Wolff’s law
Functions of Ca2+
- blood clotting
- muscle contraction
- release of neurotransmitters from nerve cells
-role in electrical signals in nerve cells
- low blood calcium levels
- muscle spasms
- tingling sensations
- convulsions if there is a 35% decrease in blood Ca2+
Hypocalcemia
- high blood calcium levels
- muscle weakness
- kidney stones
- confusion
Hypercalcemia
- from the parathyroid glands
- stimulus for its release is low blood Ca2+ levels
- overall function is to help increase blood Ca2+
Parathyroid hormone (PTH)
Vitamin D3 is needed for it to be made
- works with PTH to reduce Ca2+ loss in urine
- enhances Ca2+ absorption from the intestines into the blood
Calcitriol from the kidneys
Helps lower blood Ca2+ levels by inhibiting the activity of osteoblasts
Calcitonin
Collections of blood confined within an organ or spaces
Hematoma
Connective tissue fibers and cartilage
Callus formation
Between the ends of the broken bones
Internal callus
Collar around the break
External callus
Formation of spongy bone
- replaces cartilage of the internal and external calluses
Callus ossification
- compact bone replaces spongy bone
- part of the internal callus is removed restoring the marrow cavity
Remodeling
