Structure and Function of the Skeletal System Chapter 42 Flashcards
Functions of Skeletal System
- Support of the body
- Protection of soft organs
- Movement due to attached skeletal muscles
- Storage of minerals and fats
- Blood cell formation
Parts of the Skeletal System
Axial skeleton
Appendicular skeleton
Bones (Connective)
Cartilages (Connective)
Ligaments
Joints
Axial skeleton-
Skull and bones that support it
Includes vertebra and ribs
80 bones
Appendicular skeleton-
Limbs
126 bones
How many bones are there in the skeletal system?
206
Connective Tissues-
Cartilages 3 Types
Hyaline
Elastic
Fibrocartilage
Hyaline (most important)
Ribs, sternum, vertebrae, Articulating surfaces of movable joints
Essential for growth
Withstands stress
Injury does not heal
May become scarred or calcified (may become bone)
Elderly people’s articulating cartilage may be worn down over time.
Elastic Cartilage
Similar to hyaline but more elastic
Flexible
Ear auricle, epiglottis, & larynx
Fibrocartilage (dense)
Intervertebral Disks, knee menisci, symphysis pubis & some areas where tendons attach to bones
Shock absorber
Resistant to compression and shearing
Lets you move twist or bend (like spine)
has the greatest tensil strength
Where do connective tissues get nourishment from?
synovial fluid
Cartilage is ________ so i doesn’t heal well.
avascular
Radiculopathy
radiating pain from a disc squishing a nerve
Bone
Connective Tissue
- Hard Tissue provides support and protection
- Storage of Calcium and Phosphorus
- has extracellular matrix
Periosteum
hard outer covering of a bone
endosteum -
inner lining of periosteum on a bone
Compact bone – (aka cortical bone)
hard strong layer
Uniform thick and hard
Spongy bone – (aka cancellous bone)
at ends of long bones
Small needle-like
pieces of bone
Many open spaces
Filled with marrow
Marrow cavity –
hollow in middle of long bones
Haversian System
Structure of compact bone
Rings of bone tissue with blood vessels and nerves in the center
Bone Marrow
Red marrow – produces blood cells and clotting factors
Yellow marrow – stores fat
Red marrow –
- produces blood cells and clotting factors
- Found in humerus, femur, sternum, ribs, vertebrae, pelvis
- Produces RBC 2 million per second
Yellow marrow
stores fat
Found in many bones
Children have more _______ marrow and less ______ due to the fact that their bodies are still growing
more red , less yellow
Hematopoiesis
the formation and development of blood cells.
Bone Cells
Osteoprogenitor Cells
Osteoblasts
Osteocytes
Osteoclasts
Osteoprogenitor Cells
Differientiate into several cell types
Osteoblasts
Bone-forming cells - Alkaline phosphatase
Produce Type I collagen
Responds to Parathyroid Hormone
Produce Osteocalcin
(pull together osteoblasts, calcium and phosphate to lay down new bone)
Osteocytes (directors)
Mature bone cells
tell osteoclasts and osteoblasts what to do
Osteoclasts
Bone-destroying cells “bone-chewing”
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts
take down the old bone to lay down the new bone
Bone-remodeling units
Repairs microscopic injuries and maintains bone integrity
has 3 phases
What are the three phases of bone remodeling
Phases
- Activation of the remodeling cycle
- Reabsorption
- Formation of new bone
What element is necessary to have for bone remodeling
Vitamin D.
When it pertains to bones, elderly people can develop ________.
Osteoporosis
Calcitriol -
Form of Vitamin D
Promotes Osteoclast activity
↑blood Calcium
Produced by UV radiation
Best way to get vitamin d
helps increase the breakdown of bone.
Bone breakdown = more _______ in the bloodstream that can be used later in _________.
calcium, bone formation
Parathyroid consists of _____ glands
4
Calcium Homeostasis
Parathyroid Hormone (PTH)
TELLS TO BREAK DOWN BONES!
Secreted by Parathyroid gland to ↑blood Ca+
Stimulates Osteoclast→Ca+ release
Promotes Calcium resorption by kidneys
(Low blood calcium stimulates)
Calcium Homeostasis
Calcitonin-
TELLS TO STOP BREAKING DOWN BONE!
Secreted by Thyroid gland to ↓blood Calcium
↓Osteoclast activity ↑Osteoblast activity
↑Excretion of Ca+ & Phosphorus in Kidneys
Joints
- Site where two or more bones meet
(called articulations)
-Promote stability and mobility of the skeleton
deposition means
deposit
Joint classifications based on movement
Synarthroses
Synovial Diarthroidal
Synarthroses
Immovable or limited movement
No Joint cavity
Synovial Diarthroidal
Freely movable (articulate capsule) Joint Cavity Containing synovial fluid
(can repair and heal but not well)
What is the most complicated joint in the human body
the shoulder
tendonitis
inflamed tendon that causes squeezing resulting in pain and reduction of mobility.
Tendons
Strong and not elastic
Tendons connect muscles to bone
Ligaments
connect bones to one another
Strong and not elastic
more pliable than tendons
Tendinosis
Painful degradation of collagen fibers
Bursitis
Inflammation of a bursa
Skin over bone, skin over muscle, and muscle and tendon over bone
Caused by repeated trauma
Septic bursitis is caused by a wound infection
