Lecture one-MSK (Houston) Flashcards
Structure of long bone
- What is at the end of long bones (bone and cartilage type)?
- What is the epiphyseal line?
- What is at the middle of the long bone (bone type and cavity)?
- What is lining and contained in medullary cavity?
- Proximal/distal epiphysis that is spongy bone+red bone marrow and articular cartilage to decrease friction of bone on bone
- Epiphyseal line or plate is a thin layer of cartilage that lies between the epiphyses and metaphyses, and is where the growth of long bones takes place
- Middle is the diaphysis that is made up compact bone with a medullary cavity
- Medullary cavity is lined by endosteum and has yellow bone marrow
What is the diaphysis? What does it contain?
shaft that provides leverage
* Medullary cavity (marrow cavity)—space in the diaphysis of a long bone that contains bone marrow
What are the epiphyses? waht does it provide?
enlarged ends of a long bone
* Strengthen joint and anchor ligaments and tendons
- What is articular cartilage?
- What is the nutrient formina?
- Articular cartilage: layer of hyaline cartilage that covers joint surface; allows joint to move more freely
- Nutrient foramina: minute holes in bone surface that allows blood vessels to penetrate
What is the periosteum? What are the two layers?
external sheath covering most of bone
Outer fibrous layer of collagen
* Some fibers continuous with tendons
* Perforating (sharpey’s) fibers—penetrate into bone matrix to give the tendons something to adhere to
Inner osteogenic layer of bone-forming cells
* Important to bone growth and healing of fracture
What is the endosteum? What does it have?
thin layer of reticular connective tissue lining marrow cavity
* Has cells that dissolve (reabsorb) osseous tissue and others that deposit it
- What is the epiphyseal plate (growth plate)? What does it enable?
- What is the epiphyseal line?
- area of hyaline cartilage that separates epiphyses and diaphyses of children’s bones. Enables growth in length
- Epiphyseal line—in adults, a bony scar that marks where growth plate used to be
What is the histology of compact bone?
- Spongy bone has trabeculae and spicules (thinner)
- Perforating canals go off at a 90 degree angle
- Compact bone is made up of osteon
- The osteon has oseocytes that is stuck in their own secretion (within lacunae)
Histology of compact bone reveals osteons (haversian systems):
- How does osteons surround central canals run? What runs through the central canal?
- Bone matrix deposited in what?
- What are perforation canals?
- What is circumferential lamellae?
- What is interstitial lamellae?
- Osteons surround central canals that run longitudinally through shafts of long bones. Blood vessels and nerves travel through central canal
- Bone matrix deposited in concentric lamellae. Onion-like layers around each central canal
- Perforating canals — transverse or diagonal passages
- Circumferential lamellae fill outer region of dense bone
- Interstitial lamellae fill irregular regions between osteons
What is the ratio of the matrix of osseous tissue?
by dry weight, about one-third organic and two-thirds inorganic matter
For the organic matter part of the matrix of osseous tissue:
* Synthesized by what?
* What is secreted?
- synthesized by osteoblasts (then will be trapped in their secretations)
- Collagen, carbohydrate–protein complexes, such as glycosaminoglycans, proteoglycans, and glycoproteins
CARBON BASED
For the inorganic matter part of the matrix of osseous tissue:
* What are the components?
- 85% hydroxyapatite (crystallized calcium phosphate salt)-> Need or will have soft bones
- 10% calcium carbonate
- Other minerals (fluoride, sodium, potassium, magnesium)
For spongy bone:
* Lattice of bone is covered with what?
* What are spicules?
* What are thin plates of bones?
* What are the spaces filled with?
* What is there a few of?
* What developes along bone’s lines of stress?
* What does it provide?
- Lattice of bone covered with endosteum
- Slivers of bone called spicules
- Thin plates of bone called trabeculae
- Spaces filled with red bone marrow
- Few osteons and no central canals
- Trabeculae develop along bone’s lines of stress
- Provides strength with **minimal weight. **
Think about skull: the middle is spongy bone so that way it is lighter
Explain the process of bone repair
Old bone removed/resorbed (broken down) before new tissue replaces it
1. Osteoblasts sense microcracks, secrete recpetor activator of nuclear factor KB ligand (RANKL)
2. RANKL binds to RANK receptors on monocytes-> causes them to fuse, form multinucleated osteoclast cells
3. Osteoclasts secrete lysosomal enzymes (mostly collagenase)-> digest collagen in bone matrix-> create surface holes (Howship’s lacunae), hydrochloric acid-> dissolves hydroxyapatite into soluble calcium, phosphate
4. Osteoblasts secrete osteoprotegerin-> Deactivates RANKL, slows down osteoclast activity (before osteoclast apoptosis), osteiod seam (mostly collagen)-> fill in Howship’s lacunae
5. Calcium, phosphate deposit on seam forming hydroxyapatite
6. Some osteoblasts get trapped within lacunae-> turn into osteocytes
- What does the achieving maximus peak bone mass depend on?
- What are all negative impact on the acquisition of peak bone mass?
- After bone growth is completed, bone mass is determined by what?
- What is also very important in determining bone mass?
- Achieving maximum peak bone mass depends on optimal nutrition, physical activity, general health, and hormonal exposure throughout childhood and adolescence.
- Inadequacies in nutrition, weight-bearing exercise, and gonadal steroid exposure all have a negative impact on the acquisition of peak bone mass.
- After bone growth is completed, bone mass is determined by the level of peak bone mass attained and the subsequent rate of loss.
- Genetics are very important in determining bone mass.
What are the different hormones that are important in Calcium balance?
What is wolff’s law?
Tension and compression cycles create a small electrical potential that stimulates bone depostiion and increased density at points of stress
* Adopt to stress so increase stress, add bone and decrease stress, decrease bone
- What are the three functional classification of joints?
- What are the three structural classifications of joints?
Three functional classifications
* Synarthroses: no movement -> Symphyses, first rib to sternum+ growth plate (hyaline cartilage)
* Amphiarthroses: a little movement
* Diarthroses: free movement
Three structural classifications
* Fibrous
* Cartilaginous
* Synovial
- What is articular cartilage?
- What is the small potential space in synovial joints?
- What are the layers of articular (joint) capsule?
- What is the synovial fluid made up of and what does it do?
Articular cartilage: hyaline cartilage
Joint (synovial) cavity: small potential space
Articular (joint) capsule
* Outer fibrous capsule
* Inner synovial membrane
Synovial fluid
* Viscous slippery filtrate of plasma + hyaluronic acid
* Lubricates and nourishes articular cartilage
What are the three possible types of reinforcing ligaments?
- Capsular (intrinsic) — part of the fibrous capsule
- Extracapsular — outside the capsule
- Intracapsular — deep to capsule; covered by synovial membrane
What is the synovial joint rich nerve and blood vessel supply>
- Nerve fibers detect pain, monitor joint position and stretch
- Capillary beds produce filtrate for synovial fluid
- What is a bursa?
- What the tendon sheath?
- What is the meniscus?
- Bursa: fibrous sac filled with synovial fluid, located between muscles, where tendons pass over bone, or between bone and skin
- Tendon sheath: elongated cylindrical bursa wrapped around a tendon
- Meniscus: moon-shaped cartilage in knee; in each knee. Absorb shock and pressure. Guide bones across each other and improve their fit together. Stabilize the joints, reducing the chance of dislocation
Dense packed, parallel collagen fibers:
* What are the characteristics?
* What do tendons attach? Ligament?
- Densely packed, parallel collagen fibers (uniform structure)
- Compressed fibroblast nuclei
- Elastic tissue forms wavy sheets in some locations
- Tendons attach muscles to bones and ligaments hold bones together
Hyaline Cartilage:
* What are the characteristics?
* What are the functions?
* What are the locations?
- Hyaline cartilage: Clear, glassy appearance because of fineness of collagen fibers
- Eases joint movement, holds airway open, moves vocal cords, growth of juvenile long bones
- Locations: articular cartilage (long bone), costal cartilage, trachea, larynx, fetal skeleton
What is the skeletal muscle anatomy? (layers)
- Most outer layer: Epimysium which is around the muscle
- Middle: Perimysium which wraps perimysium
- Inner: Endomysium which wraps muscle fibers
- All of them come together to form tendon