Lecture 8 Flashcards
What is a joint? What is the point where bones meet called?
A joint is a point which holds bones together, it incorporates the bone shapes and soft tissues and are what allow us to or in some cases limit our movement. The point where bones meet is called an articulation.
What soft tissues are associated with joints and how much inorganic component does it contain?
Joint soft tissues have no inorganic component and consist primarily of two cartilage types, either Hyaline/articular cartilage or fibrocartilage.
What is the general cartilage composition? how do cells within it recieve nutrients and what does this mean about repair?
Collagen fibres contained with a ground substance, contains chondrocytes which live in lacuna and nutrients are diffused through the extracellular matrix by joint loading (a non vascular system). This non vascular system means nutrients do not reach the cells easily and as such repair is difficult and takes a very long time (longer than bone).
What are the structures of fibrocartilage and hyaline cartilage? What are their main functions in general?
Hyaline: collagen fibres are barely visible, high water content and a smooth frictionless surface. Mainly functions to resist compression.
Fibrocartilage: collagen fibres form bundles throughout the matrix, the orientation of these fibres aligns with stresses experienced and hence runs essentially parallel. Functions to resist compression and tension.
What are the functions of hyaline and fibrocartilage in the joints? What can cause these too degrade?
Hyaline: provides frictionless movement in bones in synovial joints, moulds to surfaces of bones where they articulate.
Fibrocartilage: Fibrocartilage tissue provides support and rigidity to attached/surrounding structures and is the strongest of the three types of cartilage.
Both degrade with age and trauma.
What are the menisci? What is the response to mechanical stress? How does it help?
Concave discs of fibrocartilage found at the knee joint which act to deepen articulation at the knee (providing more support and spreading out the force recieved at the knee joint over a larger area), it can adapt its shape to stresses on joint movement.
What is bony congruence? What is its relationship to soft tissue at a joint?
Bony congruence is the sum of the bone surfaces that form an articulation, less bony congruence means more soft tissue is needed for support.
What is the nucleus pulposus and what does it function to do?
The nucleus pulposus is the inner gel like center within the intervertebral discs, it functions as a shock absorber, absorbing the impact of the body’s activities and keeping the two vertebrae seperated.
What are ligaments and tendons? What are they constructed from, what do they do and what cells produce them?
Ligaments connect bone to bone and function to restrict movement away from itself e.g lateral will restrict adduction, medial will restrict abduction.
Tendons connect muscle to bone and functions to facillitate and control movement via contraction.
Both are made from dense fibrous connection tissue, a tissue type produced from fibroblasts constructed largely of collagen which functions to resist tension. Has some vascularity but has a minimal ability to repair with bone and is very slow healing.
What is elastic cartilage?
A cartilage type similar to hyaline cartilage but with the addition of many yellow fibers. Found primarily in the outer ear, Eustachian tube and epiglottis.
