Session 1 Flashcards
surfaces of the foot?
Top = dorsal Bottom = plantar
Functions of bone?
Support Movement (joints and muscle attachments) Protection Haematopoiesis Stores calcium and phosphate Stores growth factors and cytokines
Fibrocartilage is higher in what than hyaline cartilage?Purpose?
Higher collagen content Shock absorption (knee menisci)
Hyaline cartilage aids what in joints?
Frictionless movement
What makes bone more rigid than any other connective tissue?
Hydroxyapatite/ Calcium phosphate (CaPO4) mineralises the extracellular matrix
Which components of bone confer
- compressive strength
- tensile strength
Hydroxyapatite / Calcium phosphate (CaPO4)
Collagen
What secretes osteoid?
What does it contain?
Osteoblasts
- Main protein is collagen Some osteocalcin and osteopontin
- Calcium phosphate/ hydroxyapatite to mineralise the extracellular matrix
What do osteoclasts look like?
Describe resorption
Multinucleate cells, often in a resorption pit
- Bone breakdown
- Mineral absorption
Osteoclasts secrete acidic chemicals onto the bone surface to dissolve it.
The surface becomes ruffled, increasing surface area for mineral absorption.
The cell absorbs the ionic forms of calcium and phosphate which it later releases into the extracellular fluid for passage into the blood
What do osteocytes do and how do they communicate with each other?
Involved in signalling processes of bone (trapped in lacunae of the bone matrix)
Communicate via filipodia which extend through canaliculi of bone
What is the axial and appendicular skeleton?
Axial is the longitudinal axis of the body (skull, ribs, vertebrae)
Appendicular is the limbs (appendages)
Define these terms of the long bone;
Diaphysis
Metaphysis
Epiphysis
Diaphysis is shaft of the bone, contains the medullary cavity
Metaphysis is the distal shaft, adjacent to the epiphyseal line
Epiphysis is the most distal part of the bone (rounded), on the opposite side of epiphyseal line
What is the epiphyseal line?
The line which replaces the epiphyseal growth plate once the adult is fully grown
Where is red marrow present and what is it?
What is yellow marrow?
In the medullary cavity of long bones, site of haematopoiesis
Yellow marrow replaces red marrow in the adult and has a high fat content
Through what does the nutrient artery enter the long bone?
Nutrient foramen
Where do you find sesamoid bones?
What is their function?
Within a tendon
Protect the tendon from stress ad wear
Risk factors for avascular necrosis of bone?
Fracture Alcoholism Excessive steroid use Alcoholism Radiation exposure Decompression sickness Thrombosis High blood pressure
How can radiation exposure cause avascular necrosis of bone?
How about decompression sickness?
Radiation can obliterate small arteries supplying bone
In decompression sickness, bubbles of nitrogen can obstruct blood flow (bubbles can form and move anywhere in body)
3 types of joint and their differences
- Synovial (synovial fluid in joint cavity)
- Fibrous (bones united by collagen fibres)
- Cartilaginous (bones united by cartilage)
Differences between primary and secondary cartilaginous joints?
Another name for a secondary cartilaginous joint?
Give an example of each
Primary are lined by hyaline cartilage and are completely immobile.
E.g. epiphyseal growth plates of long bones
Secondary are lined by hyaline cartilage with a pad of fibrocartilage between them. They are also called symphyses.
E.g. pubic symphysis
What does a condyloid joint resemble?
Give an example
Stacking one bowl into another
The atlanto-occipital joint at the base of the skull
What does the tendon sheath do?
What is the structure?
Wraps around tendons to reduce friction associated with tendon movement
Elongated bursa (sac filled with synovial fluid)
Function of synovial fluid?
Reduce friction
Shock absorber
Transport nutrients to and away from the articular cartilage
(The cartilage is avascular, the fibrous capsule and ligaments have a poor blood supply).
What does relaxin hormone do during pregnancy?
Relaxes the pelvic joints towards the end of pregnancy
When a joint is highly ____ it is less ____
highly mobile; less stable
Highly stable; less mobile
