Lecture 1: Muscle and Exercise Physiology Keynote Flashcards
What mechanisms dictate how much muscle mass changes in the body?
Muscle mass is a balance between protein synthesis and protein degradation.
What happens if cytoskeletal proteins of muscles are damaged?
It can lead to devastating diseases (eg muscular dystrophy)
What happens if the length-tension relationship is dysrupted?
Dysruption of the length tension relationship can cause damage to the overall muscle architecture.
What kinds of muscle fibers are there?
Muscle fibers exist as either “pure” or as hybrids
What do “pure” muscle fibers consist of?
One type of MyHC
What do hybrids contain?
Multiple forms of MyHC
How do muscle fibers work in the “big picture” of muscles?
Muscles are typically composed of several different fiber types but can be predominantly a certain muscle type based on requirements.
How can muscle fiber composition be changed in a certain muscle?
Drug therapies
Physical Exercise
What are the goals of interventions to attenuate muscle wasting?
To attenuate muscle atrophy
To promote muscle strength
To do both these functions while not increasing muscle fatigue
What are the causes of disuse atrophy of muscles?
Prolonged bed rest
immobilisation
Plaster casting
Hindlimb unweighting
Spaceflight
What happens during spinomuscular atrophy?
Nerve contact to muscle is lost and electrical contact with muscle is required to prevent atrophy.
What happens during cancer cachexia?
Muscle wasting and fat loss resulting in a reduced quality of life.
Impaired chemotherapy and radiotherapy results as well.
Which cancer patients typically get cachexia?
Up to 80% of Lung, pancreatic, and gastrointestinal cancer patients early in disease.
What percentage of cancer patients die of cachexia?
more than 20%
What typically causes muscle wasting in the ICU?
Significant inflammatory response typically is the cause
