Exam 1 Part Three Flashcards
The flat bone of skull is formed by
Intramembranous ossification
Contains concentric lamallae
Osteon
Spongy bone is formed by
Trabeculae
End of a long bone
Epiphysis
Organic components of bone matrix
Osteoid
The parathyroid hormone stimulates
Osteoclasts to become active
The endosteum lines
The medullary cavity
Osteoclasts are responsible for
Bone resorption
Vitamin D increases
Calcium absorption in intestine
Hydroxyapatite is
Calcium phosphate/ hydroxide crystals
The immature cells that produce osteoid are called
Osteoblasts
Hyaline cartilage is found in these places
Trachea, layrnx, fetal skeleton
A small space within compact bone housing an osteocyte is termed a
Lacuna
Endochondral ossification begins with a _____ model of bone
Hyaline cartilage
Production of new bone _______as a result of increased sex hormone production at puberty.
Increases rapidly
An epiphyseal line appears when
Epiphyseal plate growth as ended
The condition of inadequate ossification that may accompany aging and is a result of reduced calcification is called
Osteopenia
The femur is an example of a?
Long bone
A large, rough projection of a bone is termed a
Tuberosity
Identify the three types of cartilage, describing the extracellular matrix of each type
1) Hyaline
2) Elastic
3) Fibrocartilage
A matrix of protein fibers embedded within a gel-like ground substance. Chondroblasts are the cells that produce the matrix of cartilage. Once they become encased w/in the matrix they have produced and secreted, the cells are called chondrocytes & occupy small spaces called lacunae. These mature cartilage cells maintain the matrix & ensure that it remains healthy & viable
Describe the structure of the periosteum, & list its functions
It is a tough sheath that covers the outer surface of bone, except for the areas covered by articular cartilage. Made of dense irregular connective tissue & consists of an outer fibrous layer & an inner cellular layer.
Its functions are:
*Protects the bone from surrounding structures
*Anchors blood vessels & nerves to the surface of bone
*Provides stem cells (osteoprogenitor cells & osteoblasts) for bone width growth & fracture repair
What are the types of bones?
Long bones, short bones, flat bones, irregular bones
What are the functions of the skeletal system?
1) Support: Provides structural support & serve as the framework for the entire body
2) Protection: surrounds soft tissue- ex. ribs and sternum protect the heart and lungs, - skull protects the brain
3) Movement: skeletal muscle is attached to bone so it pulls on the bone when it contracts
4) Hemopoiesis: The process of blood cell production. Red bone marrow produces red blood cells, white blood cells and other blood elements
5) Storage of mineral & energy reserves: storage of minerals and lipids(fats)—yellow marrow stores fat –(found in long bones) stores calcium and phosphate–minerals are released into the blood when needed
Endochondral ossification basic steps
1) A hyaline cartilage model of bone forms
2) Bone first replaces hyaline cartilage in the diaphysis
3) Later, bone replaces hyaline cartilage in the epiphyses
4) Eventually, bone replaces hyaline cartilage everywhere, except the epiphyseal plates & articular cartilage
5) By a persons late 20s, the epiphyseal plates have ossified, & lengthwise bone growth is complete
Osteoporosis is
In which bone mass becomes reduced enough to compromise normal function. A large number of older women & a smaller number of older men suffer from this.
Name the steps of appositional growth
1) Stem cells at the internal edge of the perichondrium begin to divide, forming new stem cells & committed cells
2) The committed cells differentiate into chondroblasts
3) These chondroblasts begin to produce & secrete new cartilage matrix. As a result, they push apart & become chondrocytes, each occupying its own lacuna
4) The new matrix has been produced peripherally, & thus appositional growth as occurred
Describe the microscopic anatomy of compact bone
Organized structure when viewed under the microscope. A cylindrical osteon is the basic functional & structural unit of mature compact bone. Osteons run parallel to the diaphysis of the long bone.
An osteon is a three-dimensional structure that has several components
- The central canal
- Concentric lamellae
- Osteocytes
- Canaliculi
Simple fracture=
(Closed) Bone does not break through the skin
Compound fracture=
(Open) Broken ends of the bone protrude through the skin
Complet fracture=
Bone is broken into two or more pieces
What are the steps to fracture repair in bones
1) A fracture hematoma forms
2) A fibrocartilage (soft) callus forms
3) A hard (bony) callus forms
4) The bone is remodeled
comminuted fracture is
Bone is splintered into several small pieces between the main parts
Incomplete fracture=
Fracture extends only partway across the bone
Greenstick fracture=
Partial fracture; convex side of bone breaks-the other side is bent
Transverse fracture=
Fracture at right angles to the long axis of the bone
Spiral fracture=
Fracture spirals around axis of long bone; results from twisting stress
What kind of secretion does the sebaceous glands secrete?
Holocrine
Sesamoid bones are
small round & flat bones that form within tendons, highly variable from individual to individual except for the patella
Flat bones
have two parallel plates of compact bone with a thin layer of spongy bone sandwiched in between them
Mesenchyme are
Star shaped cells- They are stem cells that give rise to all connective tissue
Osteoprogenitor is
From mesenchyme (usually in the endosteum) Can divide & differentiate into osteoblasts Differentiate during bone formation and after bone fracture...
Fibroblast
- Produce all connective tissue fibers
* Collagen, reticular & elastic fibers
Cartilage forming cells
Chondroblast
Encased chondroblasts
Chondrocytes
Bone forming cells
Osteoblast
Osteocytes are
Encased osteoblasts
*mature bone cells occupying lacuna (maintains bone)
Osteoclasts are
Bone destroying cells
- Giant multinucleate (fused bone marrow stem cells)
- contain lysosomes
- secret HCI
- dissolve bone matrix (osteolysis)
- frees Ca++ into the blood
What are the 3 types of cell secretion?
Merocrine (eccrine), apocrine, holocrine
What is the mature cell of cartilage?
Chondrocyte
What kind of bone is the patella?
Sesamoid bone
What is one unit of compact bone called?
Osteon
What causes skin color?
Melanin, carotene, blood