Unit 2: Skeletal System Flashcards
What is the middle of a long bone called?
Diaphysis
What are the two ends of a long bone called?
Epiphysis (proximal and distal)
What is articular cartilage and what does it do
A layer of cartilage that covers the end of a long bone where it forms a joint with another bone.
What is the purpose of articular cartilage
To form a smooth, low friction area for bones to rub together
What is red bone marrow in a long bone
Spongy-like surface that makes red and white blood cells
What is an epiphysial plate
Location in a long bone where bone will grow longer as development occurs. No bone marrow in this area.
How do doctors know when a person has finished developing through the X-ray of a long bone
When an epiphysial plate turns into an epiphysial line: the epiphysial plate is no longer depositing bone material to help it grow.
What is yellow bone marrow? Functions? Locations?
Runs down the diaphysis of long bone and fills the Medullary cavity. Helps in storage of fat and nutrients to grow the bone. (Exception: if in immediate need of blood in body, can convert back to red bone marrow)
What are the two types of bone in a long bone
Cancellous bone (spongy) and compact bone
What is the function of compact bone?
To make bone strong. Dense, close-packed bone that does not break easily
What are the two functions of cancellous bone?
- Place for bone marrow to exist. 2. makes bone lighter
What is the function of arteries in a long bone
- to deliver nutrients. 2.to take red blood cells throughout the body
What is the outer layer of the long bone called
Periosteum: thin layer of tissue
What is the purpose of the periosteum
To have a layer of osteoblasts (bone-making cells) around the bone so that bones can grow thicker, remodel, or heal.
What is the inner layer of a long bone called
Endosteum
What is ossification?
process by which new bone is created
What is remodelling?
further development of bone (continuous process where bone is created and destroyed)
What are osteoblasts?
bone-forming cells that secrete a protein in which there are osteoids
What are osteoids?
gelatin-like substance that is dischared from osteoblasts.
How is compact bone formed?
it begins as cartilage. Osteoblasts within the cartilage discharge osteoid. These deposit minerals into the cartilage, converting (ossifying) it into bone.
How is cancellous bone formed?
Begin as fibrous membranes. Osteoblasts release osteoid, which forms spongy bone. The development of the bone develops outwards from the center in membranes.
What are the 2 phases of bone remodeling?
- Osteoclasts release acids and enzymes to break down bone material
- Osteoblasts deposit new tissue by secreting proteins (osteoid)
Describe how the process of bone remodeling changes over ones life
- Remodeling is most active during early years of growth (bone production is more than bone destruction)
- Remodelling gradually declines by the age of 35
- Around age 40, process reverses (bone destruction is more than bone production)
- After 40, 5-10% of bone mass is lost each decade.
How much of the body’s calcium does a bone contain? Why is it so important to have a calcium intake?
The bones contain 99% of the body’s calcium. If not enough calcium is consumed, the calcium is taken away from bones to preform bodily functions, which weakens the bones.
How many ossification centers do short bones have?
One, near the middle
How many ossification centers do long bones have?
Three, ends and middle
Structure and function: Osteoclast
It is multi-nucleated, has a ruffled membrane (shaped like a ghost). Bone reabsorbing cells (remove old bone by acids and enzymes)
What is the sealed zone in a bone
it is the area between osteoclasts and the bone. there is where minerals from the bone is dissolved from the acids released by the osteoclasts.
Structure and function: Osteoblast
Uninucleated, bone forming cells. They secrete proteins (osteoids) to build up minerals for bones
What is an osteocyte and where is it located
a cell that senses pressure within the bone and regulates the activity of osteoblasts and osteoclasts. Located within the bone
What is a joint or articulation?
A point of contact between 2 bones
What are the two types of classifications of joints and how they related?
Structural and function. Structural classifications correspond to functional classification based on the range of motion each joint permit.
What are the three functional classifications of a joint?
Immovable, slightly movable, and freely movable
What are the three structural classifications of a joint?
Fibrous, Cartilaginous, and Synovial
What are fibrous joints and what functional classification do they belong under?
tightly bound together by connective tissue. Allow for no movement (Immovable joint). Example: suture joints in skull
What are cartilaginous joints and what functional classification do they belong under?
body of one bone connects to body of another by means of cartilage. Allow of slight movement (slightly movable). Example: intervertebral disks, ribs-sternum.
What are synovial joints and what functional classification do they belong under?
bony surfaces seperated by lubricating fluid and by cartilage. They are joined by ligaments. Allow for most movement (freely movable) Example: knee or shoulder joint.
What are the 9 characteristics of a Synovial joint?
Articulating cartilage, joint capsule, synovial membrane, fibrous capsule, joint cavity, synovial fluid, bursae, intrinsic ligaments, and extrinsic ligaments
What is articulating cartilage? (Synovial joint)
cartilage that is located at both ends of bones that come in contact with each other. protects ends of bone and allows for smooth contact surface and acts as shock absorber
What is a joint capsule? (synovial joint)
fibrous structure that contains synovial membrane and fibrous capsule
What is the synovial membrane
membrane that only allows certain nutrients to pass through into the joint
What is the fibrous capsule? (synovial joint)
a protective sleeve around the joint that keeps synovial fluid from leaking out
What is a joint cavity? (synovial joint)
The location between two articulating surfaces. It is filled with synovial fluid
What is synovial fluid?
A fluid inside the joint cavity that acts as a lubricant to reduce friction and provides nutrients to the articulating cartilage
What are bursae (synovial joint)
small flattened fluid sacs found at friction points between tendons, ligaments, and bones, which reduce friction.
What are intrinsic ligaments? (synovial joint)
thick bands of connective tissue that help thicken and reinforce joint capsule
What are extrinsic ligaments? (synovial joint)
thick bands of connective tissue that help reinforce joint by attaching bones together (separate from joint capsule)
What are the 6 types of synovial joints
- Ball and socket 2. Gliding 3. Hinge 4. Pivot 5. Saddle 6. Ellipsoid
What is a ball and socket joint
he ball-and-socket is the most maneuverable of joints, allowing for forward movement, backward movement and circular movement. With this type of synovial joint, the “ball” at one bone fits into the “socket” of another, allowing movement around three axes. The most familiar joints of this type are at the hip (the femur rests in the acetabulum of the pelvis) and the shoulder (the humerus rests in the glenoid cavity).
What is a gliding joint
This group connects flat or slightly curved bone surfaces that glide against one another. Examples of gliding joints include joints in the foot between the tarsals and in the hand among the carpals.
What is a hinge joint
Hinge joints have a convex portion of one bone fitting into a concave portion of another. They allow movement in one plane. The joints between the bones of the fingers (phalanges) and between the ulna (“inner” bone of the forearm) and the humerus (upper arm) are examples of hinge joints.
What is a pivot joint
This type of synovial joint allows rotation in one plane (uni-axial)—a rounded point of one bone fits into a groove of another. One example of a pivot joint is the atlantoaxial articular joint between the first two vertebrae in the neck, which allows the rotation of the head (as when moving the head to signify “no”).
What is a saddle joint
Saddle joints, like ellipsoid joints, allow movement in two planes (for example, flexion-extension and abduction-adduction), but do not allow for rotation like a ball-and-socket joint. A key saddle joint is found at the carpo-metacarpal articulation of the thumb.
