Skeletal System Flashcards
Identify the 5 functions of the skeletal system.
- support (bones provide a framework)
- protection (vital organs are protected by the skeletal system)
- movement (shape and arrangement of bones determine what kind of movement can occur @ joints)
- storage of minerals and growth factors (stores calcium)
- hemopoiesis - blood cell production (occurs in red marrow of certain bones)
What are the four basic components of the skeletal system?
- bones
- cartilages
- ligaments
- articulations
Describe the 3 general characteristics of cartilage, paying attention to the location of perichondrium, blood vessels & nerves, and chondrocytes as well as to the general composition of the extracellular matrix.
- skeletal cartilages are highly resilient, avascular, contain no contain fibers
- a dense CT called perichondrium surrounds most hyaline and all elastic cartilage structures
- cells of cartilage tissue are chondroblasts and chondrocytes
Compare and contrast the three types of skeletal cartilage. Thinking about where each type of cartilage is located in the body, describe how the structure of each type supports its function.
Hyaline cartilage - MOST ABUNDANT , makes up articulate cartilage , makes embryonic skeleton , MOST are surrounded by perichondrium (except articulating cartilage and ET plate)
Elastic cartilage -Makes up the epiglottis (lid that covers your wind pipe) , fibers help with repeated bending , ALL are surrounded by a perichondrium
Fibrocartilage - STRONGEST , parallel rows of chondrocytes, NO PERICHONDRIUM , compressible
Identify and describe the two mechanisms of cartilage growth.
Interstitial growth - Most prominent way (the growth during childhood and adolescence)
Process: Chondrocytes undergo mitosis in lacuna surrounded by ECM. The chondroblasts (daughter cells) secrete more matrix which causes them to move apart, expanding the cartilage within.
Appositional growth - Fibroblast in deep layer of perichondrium undergo mitosis, will continue as long as skeleton grows in length.
Process: Three layers : Perichondrium, matrix, lacuna
Cells in the perichondrium differentiate into immature chondrocytes.
Immature chondrocytes secrete new matrix.
Immature chondrocytes mature into chondrocytes that live in lacuna.
Matrix enlarges, more cells are incorporated they are replaced by divisions of stem cells in the perichondrium.
Describe in a general way the bones that make up the axial skeleton? How many bones are included in the axial skeleton?
Made up of skull and vertebrae
80 bones
Describe in a general way the bones that make up the appendicular skeleton? How many bones are included in the appendicular skeleton?
Upper and lower extremities , shoulder, pelvic girdle
126 bones
Identify and describe the role of the five types of cells of bone tissue.
Derive from bone cell lineage :
- Osteogenic cells & Osteoprogenitor - ALL DERIVE FROM THIS
some become
- Osteobalst - Matrix-synthesizing cell, responsible for bone growth, trigger calsification of the bone (a process in which calcium builds up in body tissue, causing the tissue to harden.)
some become
- Osteocyte - is the mature bone cell, monitors and maintained the bone matrix , serve as mechanical stress sensor, triggers remodeling bone tissue
Derive from WBC’s:
- Osteoclast - bone destroyer , can phagosize. dead debire in the bone like a WBC , cover internal bone surfaces (protects inner bone fro osteoblast), (breaks down bone matrix and takes up mineral and secretes them on the other side of the cell) , squamous cell like appearance
Other
- Bone-lining cells - Stimulate osteoclast differentiation , prepare bone surfaces for an osteoclast to move-in
Name the organic portion of bone matrix.
osteoid
What materials make up the organic and the inorganic parts of the bone matrix?
Inorganic - mineral salts, especially hydroxyapatite (make up 50-65% of bone tissue)
- tiny packed tightly around collagen fibers which helps resist compression forces
- has calcium phosphate (helps with healthy bone development)
organic - osteoid
- makes 25 - 30% of the the matrix
- composed of ground substance and collagen fibers
(bone forms when osteoids calcify)
Which of the above materials parts of the bone matrix are primarily responsible for the tensile strength (i.e., ability to resist stretching and twisting forces between its ends) of bone? for the compression strength of bone? Which of these materials makes bone hard and heavy?
inorganic
What are the primary minerals stored by the bones?
calcium phosphate, makes hydroxyapatite (make up 50-65% of bone tissue)
What is the general function of spongy bone? of compact bone?
provides balance to the dense and heavy compact bone by making bones lighter so that muscles can move them more easily. ; It provides protection and strength to bones.
Describe the general structure of a long bone.
look at outline for explanation
articulating cartilage
epiphysis
redmarrow
epiphyseal lines
diaphysis
- medullary cavity
–endosteum (internal) covers trabeculae of spongy bone
—periosteum (external) covers external bone surfaces of the long bone
—— outer layer (made of dense irregular CT)
——inner layer
– perforating fibers (sharpeys fibers) ( intertwine with the fibers of ligaments and tendons to help anchor those structure to the bone)
Describe the medullary cavity (i.e., where is it located? what structures are found there?).
in diaphysis , site of blood cell production
Describe the structure and function(s) of the periosteum.
outer layer/ fibrous layer- dense irregular CT
inner layer/osteogenic layer - contains osteoblasts, bone lining cells, and osteoclasts
What is the function of Sharpey’s fibers (Marieb prefers to call them perforating fibers)?
tufts of collage fibers extending from the periosteum into bone matrix
intertwine with the fibers of ligaments & tendons to help anchor those structure to the bone
distribute mechanical forces over a greater surface of the bone
What is the function of nutrient foramen?
blood vessels penetrate through periosteum and pass thorough this , nutrient arteries supply the bone
What are the differences between red and yellow marrow?
red marrow - blood cell production
yellow marrow - fatty tissue
What type(s) of bone makes up the epiphyses?
compact bone externally and spongy bone internally
What is the function of the epiphyses? of the articular cartilage?
where bone growth takes place (grows from the epiphyseal plate) ; articular cartilage connects bone to another joint (shock absorber?)
What type(s) of bone makes up the diaphysis?
compact or spongy
compact bone (thickest in the middle of the shaft , thinner towards the end)
Describe the microscopic structure of compact bone, paying attention to the location of the lamellae, lacunae, osteocytes and canaliculi.
basic unit Is osteon
osteon is made of:
- lamella (matrix material that forms around the central canal)
- osteocytes in lacunae (which lie between lamellae)
- canaliculi project from lacunae
Describe the location and function of the central canals.
ridges that surround the blood vessels (made from osteoblasts)
At the center of each osteon is a central canal (also known as a Haversian canal) through which blood vessels, lymph vessels, and nerves can travel to service and signal the cells throughout the compact bone.
Describe the location and function of the perforating canals.
at the right angles of the long axis bone. connect the blood and nerve supply of the medullary cavity to the central canals (which make up the osteons)
