Joints Flashcards
What does hyaline cartilage do?
Provides low friction surfaces (elastic springy surface)
What does fibrocartilage do?
Provides resilient support
What do ligaments do?
Tie bones together
What do tendons do?
Tie muscles to bones
What does fascia do?
Wraps around to hold things in place
What does fat do?
Provides padding and reduces weight (think of floating on water– lighter packing material then tissue– as you go further down the limb weight becomes more important. Marrow of the bones- as animal gets older- bone marrow becomes fatty. Haematopoietic marrow is only retained in areas that don’t move as much- every time you move something it takes energy).
What are bones made of? (very basically)
Collagen stiffened with mineral
Aponeurosis
Sheet of fascia
What is cartilage made of?
Collagen filled with glycoproteins that hold water. When they come under load, it pushes the water out. If you hold a joint tight together for a length of time, it squeezes the water out into the joint sheath (joins the synovial fluid) and the cartilage becomes stiff and it is more likely to tear the collagen. (Think about sitting on your foot and it feels stiff).
What are ligaments and tendons made of?
Collagen +/- elastin aligned into ropes (collagen is springy so it can take a lot of stretching and recoil, store elastic energy, prevent sudden loads coming onto the skeleton. Bones don’t like being pulled, they are okay with being compressed.)
What are muscles made of?
Collagen bags of cells filled with contractile proteins. You can tell how they go into a bone because you can find the fossa, for example.
What is fascia made of?
Collagen not otherwise named (e.g. sheets wrapping limbs)
What is fat made of?
Collagen (fascia) + adipocytes stuffed with triglycerides
Why does the scapula have a serrated face?
Serrated because there are bits of bone and collagen- where you are left with collagen from the serratus ventralis was going directly into the bone.
What type of loads do muscles put on bone?
Compressive. NOT direct TENSILE loads. They SPREAD the load**** important concept
If you want to stabilize a joint that is sloppy, you put a support bandage, what is the analogous to?
Fascia
How do each part of the anatomy in locomotion act together?
Muscles provide movement, joint allow movement, posture of the body, length, position and stiffness in ligaments in tendons determine how the movement is directed. Elasticity within ligaments and tendons, along with connections between them– smooths movements and helps balance. e.g. wobbly on a bike- cerebellum has to learn a new control system.
Just having the Elastic recoil in ligaments and tendons does what?
Slows down the speed of the muscle effect on the bones. It makes the much more efficient BUT it slows them down fractionally. Ligaments evenly toned- uneven tension on ligaments causes inappropriate joint loading.
Muscles role in movement– ligaments and tendons play a part
Muscles contract and pull against ligaments. Tension surface- even a slight bump could crack the bone EXCEPT that there is an antagonistic muscle group. SO ONE SIDE RELAXES. A gradual change from one to the other. Ligaments also counteract muscle pull to provide posture. Large tendons counteracting forces- which reduces the requirement for muscle. * Muscles held contracted give a static posture and lead to generalized stiffening/ increased damage risk. * Muscles that balance ligament pull in an elasticm anner give a dynamic, efficient, posture.
Ligaments
Ligaments can only be stretched If never stretched- they passively contract become stiffer and maybe less strong. If continuously stretched- they lengthen and may become sloppy and cease to provide support. If used within an active balanced system- they will be elastic and strong and supportive.
Which posture is assisted by ligaments?
The second picture.
Balancing ligament tone allows spinal muscles to strengthen evenly. Unbalanced ligament tone means that certain muscles are overused and movement through the joints are no longer optimal. Joints then become painful and/or damaged which restricts joint movement and causes more imbalance in the system.
** horses exercised regularly and on varying terrain
What happens with uneven tension on ligaments?
Causes inappropriate joint loading
Where are fibrous joints found?
Skull sutures. Difficult to tell where the separations are. Do not have large movement. Fractions of mm. of movement- important in denistry.
Where are cartilagenous joints- where are they found? what are they made of?
Fibrocartilaginous between them. Ring of fibrous tissue either side- at the surface where bones meet. In the middle- globular mass- a remnant of the motor cord (nucleus palposes)– when there is undue pressure and the fibrous tissue (collagen) around the edge tears- it can produde up and put pressure ont the spinal cord.
****Found at the vertebrae (intervertebral discs)- symphyses (pubic and mandible), costochondral/sternal (inbetween sternum and ribs and lumbs on ribs)
(e.g. fused pubic symphyses- important in a female that is going to be breeding. Can fuse in either mandible or pubis)