Unit 2 Videos 7-9 Flashcards
What is the skeletal system composed of:
Bones and cartilage.
Bones, referred to as connective tissue, consist of:
(osseous)
Cells
Extracellular matrix (ground substance + fibers)
The living / dynamic tissues are capable of repair and growth.
Bone, referred to as an organ, consists of:
(osseous)
osseous tissue
nervous tissue
epithelial and muscle tissue
Ex, femur, humerus, clavical, sternum
Compact bone
Dense outer layer
Spongey bone
A honeycomb of trabeculae filled with yellow bone marrow.
The function of the bone
Support - Form the framework that supports the body
Protection - Provide a protection cavity for the brain (skull), Spinal cord (vertebrae), and Vital organs (rib cage)
Movement - Provide attachment points for skeletal muscles and are used as levers
Mineral storage - reservoir for calcium and phosphors
Blood cell formation ( hemopoiesis) - occurs within the red bone marrow of the bones.
What are long bones?
A bone that is longer than they are wide.
ex humerus, femur, tibia
What are short bones?
Cube-shaped bones of the wrist and ankle
Bones that form within tendons (patella)
What are flat bones?
Thin, Flattened, and a bit curved.
Ex. most bones in the skull and sternum
What are irregular bones?
Bone with complicated shapes
ex: vertebrae and os coxae
What are the regions of the long bone?
Diaphyisis
elongated, usually cylindrical shaft
provides for leverage and major weight support
compact bones with thin spicules of spongey bone extending out the word
medullary cavity ( cavity in Diaphyis)
hollow, cylindrical space within Diaphysis
contains red bone marrow
contains yellow bone marrow in adults
What are the regions of the long bone?
Epiphysis ( red bone marrow)
The knobby region at the ends of the long bone
Proximal epiphysis - end of the bone closest to the trunk
Distal epiphysis - end furthest from the trunk
Composed of:
the outer layer of compact bone
inner layer spongey
The joint surface is covered by a thin layer of hyaline cartilage:
termed articular cartilage
helps reduce friction and absorb shock in moveable joints.
What are the regions of the long bone?
Metaphysis
- the region of mature bone between epiphysis and diaphysis
Epiphyseal plate
- in metaphysis
- thin layer of hyaline cartalige
- provides for continued lengthwise growth
- remnant in adults termed epiphyseal line
What is periosteum?
Doubled layer protective membrane. Outside of the bone.
- The outer fibrous layer is dense regular connective tissue
- The inner osteogenic layer is composed of osteoblast and osteoclast
- richly supplied with nerve fibers, blood, and lymphatic vessels. enter the bone via nutrient foramina
- secured to underlying bone by Shaprleys fibers
What is endosteum?
inside of bone
- Covers all internal surfaces of bone within the medullary cavity
- an incomplete layer of cells
- contains osteoprogenitor cells, osteoblast, and osteoclast
- tough sheath covering the outer surface of the bone.
-
Structure of short, flat, and irregular bone.
- external surface of compact bone
- interior composed of spongey bone called diploe
- lack a medullary cavity
Location of red bone marrow.
in infants
- found in the medullary cavity and all areas of spongey bone
In adults
- found in the diploe of flat bones
-The head of the humerus and femur
What is osteon?
The structural unit of the compact bone.
What is lamella?
Weight-bearing, colom-like matrix tubes are composed mostly of college.
What is the central canal?
Central channel containing blood vessels and nerves.
What are Volkmann’s canals?
Channels lying at the right angles to the central canal connect the blood and nerve supply of the periosteum to the haversine canal.
What are osteoprogenitor cells?
- Stem cells derived from mesenchyme
- Produced cells that mature to become osteoblast
- located in periosteum and endosteum
What are osteoblasts?
Build bone
- Often positioned side by side on bone surface
- synthesize and secrete osteoid
Initial semisolid from bone matrix
later calcifies
- Become entrapped within the matrix they produce
What are osteocytes?
- Mature bone cells derived from osteoblast
- have lost bone-forming ability
- maintain bone matrix
- detect mechanical stress on bone
- may trigger bone matrix of new bone matrix
What are osteoclasts?
- Large, Multinuclear, phagocytic cells
- Derived from fused bone marrow
- Ruffled border to increase the surface area exposed to bone
- Often located within or adjacent to the depression pit on the bone surface. (respobrtion lacunae)
- involved in breaking down bone
What two vitamins are needed in bone formation?
Vitamin D - for calcium absorption
vitamin C - collagen formation
What does resorption mean?
to break down the bone by osteoclast
Calcium is released into the bloodstream
What organic substances compose a bone matrix?
The organic compound is osteoid, composed of collagen, proteoglycans, and glycoproteins.
What inorganic substances compose a bone matrix?
The inorganic component is formed from hydroxyapatite. Which includes calcium phosphate, other salts and ions, calcium carbonate, sodium, magnesium ion
What is ossification or osteogenesis?
- The formation and development of bone connective tissues
- begins in the embryo
- continues through childhood and adolescents
- begins by 8 through 12 weeks of embryonic development
- occurs through intramenbrous ossification or endochondral ossification
What is intramembrnous ossification?
- formation in most of the flat bones in the skull and clavicle
- fibrous connective tissue membranes are formed by mesenchymal cells
Steps of intramembranous ossification.
- ossification centers appear in the fibrous connective tissue membrane ( osteoid secret)
- Osteiod is secreted within the fibrous membrane and calcifies ( become osteocytes trapped in lacunae)
- woven bone (trabeculae) and periosteum form ( blood vessels pass through diploe)
- lamellar bone replaces woven bone, just deep to the periosteum. Red bone marrow appears
What bones are formed from intramembranous ossifaction?
Flat bones of the skull, some facial bones, the manubrium, and the central part of the clavicle.
What is endochonral ossifaction?
- begins with a hyaline cartilage model
- produce most bones of the skeleton, including bones of upper and lower limbs, pelvis, vertebrae, and ends of clavicle.
Process of endochonral ossifaction
- The fetal hyaline cartilage model develops
- Cartalige calcifies, and a periosteal bone collar forms around diaphysis
- primary ossification center forms in the diaphysis
- secondary ossification center form in the epiphysis
- bone replaces cartilage, except for the growth plate. (epiphyseal plate)
- epiphyseal plates ossify and turn into epiphyseal lines. ( stop growing lengthwise)
Interstitial growth
Bone growth in length
- occurs within Zone 2 and Zone 3
- pushes zones of resting cartilage towards the epiphysis
- Flexible hyaline cartilage permitting growth
- new hyaline cartilage replaced by bone
- similar to endochondral ossification during development.
Appositional Groth
Width of bone growth
- Bone grows in diameter
- occurs within the periosteum (outermost side)
- bone matrix deposit within layers parallel to the surface
- Layers termed external circumferential lamella
as they increase in number, they increase in diameter
-osteoclast resorb bone matrix along the medullary cavity
- transforms infant’s bone into adult bone
What is mechanical stress?
- occurs in weight-bearing movement and excise
- required for normal bone remodeling
- detected by osteocytes and communicated to osteoblast
- osteoblast synthesis of osteoid
- cause an increase in bone strength
- results from skeletal contraction and gravitational forces
What do you do to increase bone mass?
Exercise from weight lifting, running, walking, etc.
What do you do to decrease bone mass?
-removal of mechanical stressors
- reduce collagen formation
- demineralization
decreased strength of unstressed bone in immobilized fracture
Hormones used in bone growth and remodeling
Growth hormone (somatropin)
thyroid hormone
sex hormones: estrogen and testosterone
Glucocorticoids
serotonin
Two hormones that regulate calcium.
Calcitriol ( comes from light or diet made from kidney)
parathyroid ( made from parathyroid glands)
Why is improtant to regulate calcuim?
- initiation of muscle concentration
- exocytosis of the molecules from the cell, including neurons
- stimulation of the heart by pacemaker cells.
- blood clotting
Parathyiod and calcitriol secret in response to?
Low blood calcium levels
What is calcitonin?
It ensures calcium leaves the bloodstream and gets back onto the bone or is released by excretion.
Produced by the thyroid gland
Process of bone fracture
- a fracture hematoma forms (blood-cleared diaphysis needs to be rebuilt)
- The osteoblast builds up the bone-secreting osteoid. It becomes hardened by calcium, and osteoblasts get trapped in lacunae. Turn into osteocytes.
- build compact and spongey bone. Blood vessels go in canals.
- then you have a clear modular cavity where yellow bone marrow resides.
At what age do all bones become entirely ossified?
25 years old
What happens to bones in old age?
Bone resorption predominates. In other words, osteoclasts outnumber osteoblasts, making bones weaker.
What is called when bones lose mass?
osteoprorosis. Happens in small people. Or lacking the genes for vitamin D docking.
What are the three regions of the axial skeleton?
- Skull
- Bony thorax (sternum and rib cage)
- vertebral collum
80 bones
What is the general function of the axial skeleton? And what bones are considered part of the axial skeleton?
Function - protection of vital organs ( brain, heart, lungs, etc)
Composed of the skull, vertebral collum, and thoracic cage.
Two parts of the skull.
Cranium bones
facial bones
Function of the cranium.
It protects the brain and is the attachment site for the head and neck muscles.
the function of the facial bones.
- supply the framework of the face, the sense organs, and the teeth.
- provide passages for food and air
- anchor the facial muscles of expression.
What are the cavities of the skull?
- Cranial cavity (brain)
- orbits ( eye sockets)
- oral cavity (mouth)
- nasal cavity ( lower part of the nasal bone)
- paranasal cavity (upper part between eyes)
Study lab cards!!!
When do sutures usually fuse?
usually in 40s
What bones are articulate (meet at) lambdoid suture?
parital bones and occipital bones
What are 14 facial bones?
Paired zygomatic bones, lacrimal bones, nasal, palatine bone, paired maxillae bones, and inferior bones nasal concha. Unpaired vomer and mandible.
Which vertebrae are located in the small of the back?
Lumbar, there are 5.
What ribs are true? What ribs are false? What ribs Floating?
True 1-7
false 8-12
floating 11 -12
What is the appendicular skeleton made up of?
The appendicular skeleton is made up of the bones of the limbs and their girdles.
attaches the upper limbs to the body trunk
pectoral girdles
secures the lower limbs
pelvic girdles
What are the three parts of the upper limb?
Brachium ( upper arm)
antebracium (forearm)
Manus (hand)
Name carpals bones.
Hamate ( upper under pinky)
Capitate ( upper under middle finger)
trapezoid (upper under under pointer finger)
Trapezium (upper under the thumb)
pisiform ( Lower Under pinky on top of triquetrum)
Triquetrum (lower under Hamate under pisiform)
Lunate ( lower middle )
Scaphoid ( lower under the thumb)
What transplants happen at the head of the femur?
Marrow transplants
What is the primary function of the tibia?
Very important in weight-bearing
Why are arches significant?
- Help support body weight
- ensure blood vessels on the sole are not pinched when standing
- Shape maintained primarily by foot bones themselves
- bones shaped so they can support the weight in an arch
- Solid ligaments and tendons also help maintain the shape of arches.
What has more skull has more bones?
Infant skulls
At birth, fetal skulls are?
Incomplete and connected Fontanels
What are fontanels?
- Unossified remnants of fibrous membranes between fetal skull bones
- the four fontanels are anterior, posterior, mastoid, and sphenoid
What happens in old age?
- Interervatble disk become thin, less hydrated, less elastic
- risk of disk herniation increase
- loss of stature ossify, causing the thorax to become rigid
- all bones lose mass
What is a articulation?
The space between two bones (joints)
What is the weakest point of the skeleton?
Joints
Functions of joints.
- Give skeleton mobility
- Hold Skeleton together
What is articulation site?
Where two or more bones meet.
What are three Structural classifactions of Joints
- Fibrous
- Cartilaginous
- Synovial
What are the functional classifactions of joints
- Synarthroses (Immoveable)
- Amphiarthroses (Slightly moveable)
- Diarthroses (Freely moveable)
Fibrous joints
- The bones are joined by dense regular fibrus tissue
- There is no joint cavity
- Most are immoveable (synarthroses)
- The three types are sutures, syndesmoses(between radius and ulna), gomphoses
example- between tibia and fibula, or between radius and ulna
Where are gophoses and sutures found.
- Gophoses found in jaw with teeth
- sutures found in skull
Cartilaginous joints
- Articulating bones are united by cartillage
- Lack a joint cavity
- Two types syncrondroses and sympheses
Cartilaginous joints: Syncondroses
- A bar or plate of Hyaline cartilage
- All synconroses are synarthoric
Examples epiphseal plate in children, Joint between costal cartilage of the first rib and sternum.
Cartilaginous joints: Symphyses
- Hyaline cartilage covers the articulating surface of the bone and is fused to an intervening pad of firbrocaritllage.
- Amphithrotic jonts desinged for strength and flexibility
- ex intetervertable joints and the pubis syphsis of the pelvis
Synovial joints
- those joints in which the articulating bones are seprated by fluid-containing joint cavity
- All are free and moveable diathroses
- example all limb joints, and most joints in the body
- all jonts that move
Synovial joints have all of the follwoing
- Articular cartilage
- joint cavity
- articular capsule
- synovial fluid
- reinforcing ligaments
What do synovial joints have to protect against? How do they protect?
- Have to protect against friction.
- use Bursae that have specialied fluid within
- Tendon sheaths are bursae that wrap around the tendon completely
What is the purpose of synovial fluid in the joint?
Reduce friction,shock absoprtion, and nurish chondrocytes
How is stability determined by in synovial
- Articulating surface - shapes determine what movement is possible
- liagments - unite bones and prevent excessive or undesireable movement
Muscle tone is acomplished by:
- Muscle tendons across joints acting as stablizing factor
- tendons are kept tight by muscle tone at all times
The two muscle attachments across a joint are:
- Origin - attachments to the immovable bone
- insertion - attachment to moveable bone
what is a ligament?
A ligament is a fibrous connective tissue that attaches bone to bone
What is tendon?
A tendon is a fibrous connective tissue that attaches muscle to bone
What is the relationship between mobility and stability in a joint?
The greater the mobility, the lesser the stability.
The less the mobility, the greater the stability.
Types of synovial joints: Hinge joint
- Cylindrical projections of one bone fits into a trough -shape surface on another
- motion is along a single plane
- Uniaxial joints premit flexion and extention only
- ex elbow
(like a hinge on the door one direction)
Pivot joints
Pivots from side to side.
ex axis and dens
Condyliod or Ellipsodial joints
Sit in depressions
examples between radius and carpals
saddle joints
similar to condyliod joints like two U’s meeting
Ex first metacarpal
Ball and socket joints
head of bone like femur in socket
what are the basic characteristics of synovial joints?
- Must have joint cavity
- must have synovial fulid
- must have articular cartilage
- must have ligamnets
- must have nerves
-must have blood vessels
What are sprains?
a tear of ligaments.
