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
What is the origin and insertion of a muscle
Origin is the stationary anchor point and is usually proximal in the limb
Insertion is the mobile attachment point (usually distal)
Muscles can be described as; synergists neutralisers fixators what do these terms mean?
A synergist assists the prime mover but cannot carry out the movement itself
A neutraliser stops unwanted effects of a muscle agonist
A fixator stabilises a joint. Usually the proximal joints are stabilised when the distal joint moves.
Fixators in elbow flexion?
Rhomboids- stabilise rotation of scapula
Rotator cuff muscles- stabilise shoulder joint
Concentric, eccentric and isometric muscle contraction?
Concentric- muscle shortens as it contracts
Eccentric- muscle lengthens
Isometric - muscle length stays the same
When you land a jump, what type of contraction do the quadriceps undertake?
eccentric for shock absorption
How are the fascicles arranged in a unipennate muscle?
All on the same side of the tendon
What is a fascial compartment?
region of the limb surrounded by deep fascia; it contains muscles, nerves and blood vessels.
What are the superficial and deep fascia?
They are bands/ sheets of connective tissue
Superficial fascia is found in most regions of the body; also called subcutaneous fat. Found under skin; around organs, etc.
Deep fascia is much thicker, elastic and able to resist strong unidirectional forces. It encloses muscle compartments and adhesion to skin in the hand forms palmar creases
How are the collagen and elastin fibres arranged in deep fascia?
wavy pattern parallel to direction of pull
deep fascia can resist great unidirectional forces
Tendons vs ligaments vs aponeuroses
Tendon- muscle to bone
Ligament - bone to bone
Aponeurosis - muscle to muscle*
*(sometimes muscle to bone)
What is Hilton’s law?
The nerves which supply the joint itself also innervate the muscles causing movement around said joint
(the nerves also supply the skin overlying the insertion of these muscles).
