Midterm - Week 1 Flashcards
What are the 7 parts of a long bone?
- 1 diaphysis
- 2 metaphysis
- 2 epiphyseal plates (if growing) or lines (in adult). Aka physis
- 2 epiphysis
What is deep to the articular cartilage?
Subchondral bone
What is the membrane lining the outer bone?
Periosteum
What is the thick outer layer of an extremity joint
Fibrous capsule
What are the slippery caps of adjacent bone ends
Articular cartilage
What are the two intra-articular cartilages? Where are they?
- Disc (AC, SC, TMJ, triangular fibrocartilage in wrist)
- menisci (knee)
The synovial cavity is rich in GAG’s, especially _________
Hyaluronic acid (key contributor to cell proliferation)
What are the two layers of synovial membrane?
- intima = epitheloid
- sub-intima = CT (outer). Vascularized and has pain receptors. 3 types: areola, fibrous, adipose
What are 2 functions of the synovial membrane
- produces and resorbs synovial fluid
- provides immunity to joint cavity
What are the four cell types of synovial membrane?
- Macrophage (WBC) —Immune/Infection support - Lysosomes: —Breaks down and removes waste - Fibroblast: —Wound healing and structural framework - Secretory: —Creates and secretes synovial fluid
What is the purpose of fenestrated capillaries in the synovial membrane?
Increase fluid exchange
What is the purpose of lymphatic vessels in synovial membranes?
Removes fluid and returns to circulatory system
What is the main function of bursae
Reduce friction to allow free movement
also shock absorbers
What is the most common articular cartilage type?
Hyaline
What are the main components of articular cartilage?
- Low cell population density
- H20 (80% of total weight)
- Collagen (60-70% of dry weight)
- GAG’s (proteoglycans, 30-40% of dry weight)
Which 3 1/2 joints are lined by fibrocartilage?
AC, SC, TMJ, iliac portion of the SI
What are the two most important GAG’s
Chondroitin sulfate
Glucosamine sulfate
Slow oscillations of the articular cartilage is (good/bad).
It (stimulates/suppresses) matrix syntheses and (enhances/inhibits) chondrolysis
Good
Stimulates
Inhibits
Traumatic compression or no oscillations of the articular cartilage is (good/bad)?
It (stimulates/suppresses) matrix synthesis and (enhances/inhibits) chondrolysis
Bad
Suppresses
Enhances
In DJD do these increase or decreases
- cell numbers
- GAG’s
- lubrications
- calcification
- cell numbers decrease (population density)
- GAG’s decrease
- lubrication decreases
- calcification increases
Subchondral bone is a shock absorber. It is ____ times stiffer than articular cartilage but ____ times less stiff than dense bone
10x
100x
What changes in the subchondral joint are seen in DJD?
- Increase calcification -> increases rigidity
- Increased thickness ->Impedes waste removal and nutrient delivery
- sclerosis on x-rays
- Decreased shock absorption
- Mechanism/ vicious cycle -> Increased stress, weakness, abnormal support, decreased cartilage, decreased synovial fluid
The intra-articular cartilage is (highly/not) innervated and is vascularized in the outer ____
Highly, outer 1/3
Aging of the intra-articular cartilage decreases hat 4 things?
Vascularization
Chondrocyte population
GAG’s and collagen
Shock absorption and flexibility
Efferent muscle stimulation controlled by _________ activation/inhibition (reflexive) & central activation/ inhibition
Proprioceptive
