Physiological Laws Flashcards
When an impulse has passed once through a certain set of neurons to the exclusion of others, it will tend to take the same course on future occasions. Each time an impulse traverses it’s path, the resistance will be smaller; the passage of neural impulses become even easier for all succeeding impulses.
Facilitation
If muscle ends are brought closer together, then the pull of tonus is increased, this shortens the muscle, increases muscle tone and can cause the muscle to become hypertonic. If the muscle ends are separated beyond normal, then tonus is lessened or lost, thereby weakening the muscle. Also known as adaptive shortening and lengthening.
Davis Law
Weak stimuli activate physiological processes; very strong stimuli inhibit physiological responses.
Arndt-Schultz Law
When a painful stimulus is applied to a body part of low sensitivity (such as an organ) that is in close central connection (the same segmental supply) with an area of higher sensitivity (such as a part of soma), pain will be felt at the point of higher sensitivity rather than where the stimulus was applied.
Head’s Law
A nerve trunk that supplies a joint also supplies the muscles of the joint and the skin over the attachments of such muscles.
Hilton’s Law
Which law co-insides with this application?
When pain is felt in a certain region it is difficult to know what tissues are damaged. This is the basis for Orthopedic assessment, we stress each type of tissue to confirm or eliminate the cause of the pain. This is also why cannot palpate for pain initially but we must wait till we have a clinical impression, have an idea of what tissues are damaged and then palpate.
Hilton’s Law
The stress used to stretch or compress a body is proportional to the strain as long as the elastic limits of the body have bot been exceeded.
Hooke’s Law
Which law does this application co-inside with?
A tissue is stretched or compressed within its elastic limit it will return to is original length. If it is stretched or compressed beyond its elastic limit into its plastic zone then it will not return to its original shape.
Hooke’s Law
Muscles on one side of a joint will relax upon contraction of the antagonist muscle or muscles
Sherrington’s Law
Application -
Principle of reciprocal inhibition
Sherrington’s Law
Every change in the form and the function of a bone, or in it’s function alone, is followed by certain definite changes in its internal architecture and secondary alterations in its external conformation; these changes usually represent responses to alterations in weight bearing stresses.
Wolff’s Law
Application -
The bones of a healthy person will adapt to the stresses placed on them. This usually refers to weight bearing exercises. The converse is also true that when a bone is not stressed it becomes less dense and weaker. The body will not maintain something that is not used, it is too metabolically expensive
Wolff’s Law
Application -
When we learn to perform a specific task, walking, playing piano, massaging or writing, for the first time we fire neurons in a certain order, usually we fire too many, use too many muscle fibres adn the task is slow, we make mistakes and we use a lot of energy. Each subsequent time we refine the movement by co-ordinating the neurons better and using fewer muscle fibers. The task gets easier, faster adn uses less energy. This is the principle of motor learning and applies to every motor activity we learn from when we are babies to adulthood.
Facilitation
Application -
Small electrical impulses can help stimulate a muscle whereas a stronger one will hurt and a very strong one will inhibit the muscle. When applying massage techniques we can use less pressure and stimulate a healing response whereas with stronger pressure we can damage the tissues further and inhibit healing.
Arndt-Schultz Law
Application -
This especially applies to posture. If we have rounded, protracted shoulders the anterior muscles are short, adaptively shortened, and hypertonic whereas the posterior muscles are stretched out and inhibited, adaptively lengthened. The short muscles will lose length and need to be stimulated to return to their correct length by stretching. The lengthened muscles will have to be strengthened to increase tone and move back to the correct length.
Davis Law
