Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/57

Click to flip

57 Cards in this Set

  • Front
  • Back
What makes up the axial skeleton?
skull and associated bones (auditory ossicles and hyoid bone), the vertebral column and the thoracic cage (ribs and sternum)
What makes up the appendicular skeleton?
The Pectoral and Pelvic girdles that supprt and attach the upper and lower limbs to the trunk.
What does the skeletal system inlcude?
the bones of the skeleton, cartilages, ligaments and other connective tissues that stablize or innterconnect bones;
What is the functino of the skeletal system?
Structural support, storage of minerals and lipids, blood cell production, protection of delicate tissues, organs and leverage.
Structure of Bone:
What is osseous tissue?
Bone tissue comprised of supporting CT with specialized cells and a solid, xtracell. matrix of protein fibers and ground substance.
Structure of Bone:
Histological Organization of Mature Bone:

Hydroxyapatite
Large crystals that make up the majority of the bone matrix; accounts for 2/3 bone weight (1/3 made up of collagen fibers and Ca salts, bone cells and other cell types.
Structure of Bone:
Histological Organization of Mature Bone -

What are osteocytes?
Mature bone cells that are completely surrounded by hard bone matrix; reside in spaces called lacunae where they are interconnected by small, hollow channels called canaliculi.
Structure of Bone:
Histological Organization of Mature Bone:

What is the lacunae?
a small space containing an osteocyte in bone; situated between the lamellæ (calcified matrix), and consist of a number of oblong spaces
Structure of Bone:
Histological Organization of Mature Bone:

What are Osteoblasts?
Immature, bone-forming cells; formed via osteogenesis; sythesize osteoid, the matrix of bone prioir to calcification
Structure of Bone:
Histological Organization of Mature Bone:

What are the functions of osteocytes?
To maintain and monitor the protein and mineral content of the matrix.
Structure of Bone:
Histological Organization of Mature Bone:

What are osteoblasts?
Cuboidal cells on the inner and outer surface of bone; secrete osteoid that eventually mineralizes.
Structure of Bone:
Histological Organization of Mature Bone:

What is osteogenesis?
The production of new bone via the osteoblasts.
Structure of Bone:
Histological Organization of Mature Bone:

What happens when an osteoblast is surrounded by matrix?
It differentiates into an osteocyte.
Structure of Bone:
Histological Organization of Mature Bone:

What are osteoprogenitor cells?
Mesenchymal (stem cells) cells found in bone tissue; found in the periosteum and endosteum, lining the marrow cavities; can divide into daughter cells that become osteoblasts, important for bone fractures.
Structure of Bone:
Histological Organization of Mature Bone:

What are osteoclasts?
Giant cells w/50+ nuclei; secrete acids, causes osteolysis
Histological Organization of Mature Bone:
Cells - What is osteolysis?
An erosion process in which acids from osteoclasts dissolve the bony matrix and release amino acids and stored calcium and phosphate; this inc the Ca and P032- concen. in body fluids
Histological Organization of Mature Bone:
Cells - What determines bone strength?
Weak bones form when osteoclasts remove Ca salts faster than osteoblasts deposit the; Strong bones form when osteoblast activity predominates.
Histological Organization of Mature Bone:
Bone Tissue:
Compact and Spongy Bone
Osseous tissue has 2 types, compact bone and spongy bone; both are present in bones and have same matrix comp.
Histological Organization of Mature Bone:
What does compact and spongy form form?
Compact: Dense and solid tissue that forms the walls;
Spongy: open network of struts and plates that surround the marrow cavity.
Histological Organization of Mature Bone:

What is bone marrow?
Loose connective tissue dominated by adipocytes (yellow marrow) or by a mixture of mature and immature red and white blood and stem cells (red marrow).
Histological Organization of Mature Bone:

How do spongy and compact bone differ, structurally?
In their 3-D arrangement of osteocytes, canaliculi and lamellae.
Histological Organization of Mature Bone:
Compact bone - what are osteons?
Mature compact bone is called osteon, in it are osteocytes that surround a central canal that contain the blood vessel supply for the osteon.
Histological Organization of Mature Bone:
Compact bone - name the three lamellae found in compact bone.
Concentric (form rings around central canal), Interstitial (fill spaces b/w osteons) and circumferential (on bone surface)
Histological Organization of Mature Bone:
Spongy Bone (SB) - what's the primary diff b/w spongy and compact bone?
The parallel lamellae form struts of thin, branching plates (trabeculae) in SB and there aren't any ostens in SB, nutrients delivered via diffusion
Histological Organization of Mature Bone:
What the fx diff b/w SB and CB?
CB covers bone surfaces, it's thickest where stresses come from limited range of direction. SB in inside bones and found where stresses are few and come in many diff directions.
Histological Organization of Mature Bone:
The Periosteum - define
Covers the outer bone surface, consists of dense fibrous CT and osteoprogenitor cells.
Histological Organization of Mature Bone:
The Periosteum - functions?
isolates and protects bone from tissue, provides a route and attachment site for circulatory and nervous supply, participates in bone growth and repair, attaches the bone to the CT network of deep fascia
Histological Organization of Mature Bone:
The Periosteum - you won't find it here...
around sesamoid bones or at attachment sites for tendons, ligaments or joint capsules, or near articular cartilage of bone
Histological Organization of Mature Bone:
The Periosteum - so what happens to it around joints?
Becomes continuous w/CT to stablize joint; or becomes part of the joint capsule in fluid filled joints
Histological Organization of Mature Bone:
The Endosteum - what is it?
Found in the bone, a cellular endosteum lines the marrow cavity, contains osteoprogenitor cells, osteoblasts and osteoclasts, active during growth and repair; usually simple or incomplete epithelium
Bone Development and Growth:
When does the skeleton begin to form in utero?
6 weeks after fertilization
Bone Development and Growth:

What is ossification?
during embryonic development, either mesenchyme or cartilage is replaced by bone, this process of replacing other tissues with bone is ossification; two types.
Bone Development and Growth:

What is calcification?
The process in which calcium salts are deposited into a tissue; any tissue can be calcified, but only ossifcation reults in bone.
Bone Development and Growth:

Intramembraneous Ossification (definition)
aka dermal ossification: when bone develops from mesenchyme or fibrous CT; begins in deep layers of dermis, when mesenchymal cells differentiate into osteoblasts w/in embryonic of fibrous CT, bones that result are dermal/membrane bones; eg. roofing bones in skull, jaw, clavicle
Bone Development and Growth:

Intramembraneous Ossification - Step One of the Process
mesenchymal cells differentiate into osteoblasts that cluster and secrete matrix components that mineralizes; location of bone where this happens is the ossification center; as ossification proceeds, it traps some osteoblasts that become osteocytes.
Bone Development and Growth:

Intramembraneous Ossification - Step Two of the Process
Bone grows outwrd in small struts called spicules, growth accelerates as blood vessels reach b/w the spicules
Bone Development and Growth:

Intramembraneous Ossification - Step Three of the Process
Overtime, many ossification centers form and newly deposited bone becomes spongy bone. Continued deposition of bone via osteoblasts close to the blood vessels form compact bone.
Bone Development and Growth:

Endochondral Ossification: (definition)
begins with the formation of hyaline cartilage model, eg. limb bones, the model cont to grow by expansion of the matrix
Bone Development and Growth:

Endochondral Ossification:
Step 1 of the Process
as the cartilage enlarges, chrondocytes by the shaft grow and the matrix calcifies
Bone Development and Growth:

Endochondral Ossification:
Step 2 of the Process
Cells differentiate into osteoblasts and the inner osteogenic layer produces a bone collar (a thin layer of bone around the shaft of cartilage)
Bone Development and Growth:

Endochondral Ossification:
Step 3 of the Process
Blood supply increases, calcified matrix breaks down and is replaced by spongy bone.
Bone Development and Growth:

Endochondral Ossification:
Step 4 of the Process
Entire diaphysis is filled with spongy bone, as it enlarges a marrow cavity forms
Bone Development and Growth:

Endochondral Ossification:
Step 5 of the Process
Marks beg of inc length of bone; Center of epiphyses calcify, capillaries and osteoblasts migrate to these areas creating secondary ossification centers
Bone Development and Growth:

Endochondral Ossification:
Step 6 of the Process
Epiphyses fill with spongy bone, articular cartilage forms, epiphyseal cartilage now sep the epi from the diaphysis
Bone Development and Growth:

Endochondral Ossification:
Step 7 of the Process
Epiphyseal cartliage production slows and rate osteoblast production accelerates at maturity causing the epiphyseal cartilage to become narrow until it disappears, called epiphyseal closure.
Bone Development and Growth:

Endochondral Ossification:
Increasing Bone Diameter
Diameter enlarges via appositional growth at the outer surface, where osteoprogenitor cells add bone matrix, thus adding successive layers of circumferential lamellae.
Bone Development and Growth:

Endochondral Ossification:
Increasing Bone Diameter Process
new bone deposited in ridges by blood vessels @ bone surface, ridges enlarge and grow toward eachother until they meet and fuse, cells differentiate and form new bone; as bone diam. grows, so does the marrow cavity
Bone Development and Growth:
Formation of blood and lymphatic supply
bones formed thru endochondral ossification have 4 sets of vessels: nutrient, metaphyseal, epipyhseal and periosteal; lymphatic vessels enter osteons via canals
Bone Development and Growth:
Bone Innervation-
Sensory nerve endings branch the periosteum and sensory nerve penetrate the cortex w/nutirent arteries to innervate the endosteum, marrow cavity and epipyhses.
Define epiphysis:
The rounded end of a long bone.
Bone Development and Growth:

Factora Reg. Bone growth
nutrients, parathyroid homone that stimulates osteoclast and blast activity, calcitonin that inhibits osteoclas activity and inc Ca loss, epi. cartilage closure.
Bone Maitenance, Repair and Remodeling:
What's the turnover rate for bone?
high, each year 1/5 of the adult skeleton is broken sown and rebuilt
Bone Maitenance, Repair and Remodeling:

Changes in bone shape:
Mineral turnover and recycling allows bone to adapt to new stresses
Bone Maitenance, Repair and Remodeling:

Injury and Repair
healing of a fracture can occur if portions of the blood supply, endosteum and periosteum remain intact
Bone Maitenance, Repair and Remodeling:

Aging
as you age, your bones get thinner and weak, osteopenia develps and can progress to osteoporosis.
Bone Maitenance, Repair and Remodeling:

remodeling bones
involves simultaneous process of adding new bone and removing old bone
How are bones classified?
By anatomical classifications; they are long, sutural, irregular, short and sesamoid bones.