Skeletal muscle ageing Flashcards
rate of strength loss for men & women annually?
3.5 and 2.7 %
rate of mass loss for men & women annually?
0.47 and 0.37 %
what contributes to osteosarcopenic obesity
osteopenic obesity and sarcopenic obesity
what does osteosarcopenic obesity, increase the risk of?
fractures / morbidity - while decreasing functionality
what are the effects of loss of lean mass of 10 / 20 / 30 / 40 %
- deceased immunity and increased risk of infection
- decreased wound healing and increased muscle weakness
- pressure ulcers and pneumonia
- increased risk of death usually from pneumonia
what is the AA glutamine’s main function
to support the repair process and maintain the immune system
what are the four main things derived from ageing muscle
- metabolic dysfunction
- loss of mass
- loss of function
mitochondrial dysfunction
all contributing to reduced quality of life
why do muscles have lipid droplets deposited near mitochondria
to provide fast energy - can be observed under a minor array or electron microscope.
what are free AA
- protein repletion for growth
- oxidation ( eg excretion of urea)
- transformation ( eg gluconeogenesis)
how can carbon skeletons of amino acids be used as fuel
KETOGENESIS - removal of alpha amino acid group. leaving the skeleton to be used as a metabolic intermediate or GLUCONEOGENESIS, forming glycogen for storage.
what does carbohydrate metabolism provide
storage of glycogen and conversion of glucose
how are glycogen stores depleted
fasting and exercising
how much glycogen can the liver store
100g
what is the max glycogen storage of the body
3-500g
what are satellite cells
essentially muscle stem cels and they become less responsive to to repair leading to reduced regenerative capacity as they age
what is mitochondrial dysfunction free radical theory
Mitochondria generate atp and ros, which become scavenged in healthy muscle
- Overfeeding with reduced energy demand leads to metabolic stress and increased ros production – production is close to DNA and therefore leading to genetic lesions
what does inflammation in ageing muscle cause
stimulates the release of catabolic cytokines such as TNF alpha and IL - 6. also activating mitochondria leading to increased production of R.O.S
What are stable isotopes
naturally occurring and contain extra neutrons. Safe for use in humans as well as being biologically relavant
advantages of STABLE isotopes
- Heavy elelments can be encorporated into any compound via chemical or enyme reaction
- Behave like endogenous compounds and can trace things such as metabolism
- Differentiated form endogenous using mass spectrometry
- Allow recording of dynamic measurments such as rates instead of static like concentration
- Non radioactive
applications of STABLE isotopes
- Arterio venous balance mechanisms, sampling of blood flow of labelled compounds to assess net uptake / release and intermediatory metabolism of labelled compounds
- Allows evaluation of dynamic proteonomics (turnover of muscle proteins and plasma) and metabolics.