Human Fetal Muscle Development Study

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What percentage of muscle mass is typically reduced by the age of 65 years?

50 to 55%

25 to 30% (correct)

10 to 15%

40 to 45%

Which enzyme activity loss is mentioned as contributing to the decrease in muscle strength and power with age?

Myosin phosphorylase activity

Myosin ATPase activity (correct)

Myosin kinase activity

Myosin synthetase activity

What specific factor influences the extent of muscle-specific atrophy according to the text?

Muscle activity (correct)

Blood pressure

Bone density

Dietary intake

Which condition is NOT listed as a cause of secondary sarcopenia in the text?

Hypertension Signup and view all the answers

What age range do individuals typically experience the peak of muscle mass according to the text?

25-30 years Signup and view all the answers

Which statement about the decrease in mitochondrial size and number is true according to the text?

It results in a decrease in oxidative metabolic capacity and fatigue resistance. Signup and view all the answers

What is the definition of muscle strength?

The maximal force a muscle or muscle group can generate Signup and view all the answers

Which of the following molecular markers are associated with aging?

Lipid peroxidation Signup and view all the answers

In the context of aging, which tissues are more susceptible to the effects of age?

Post-mitotic tissues Signup and view all the answers

What is the relationship between power and muscle performance?

Power is the product of strength and the speed of movement Signup and view all the answers

Which of the following is a risk factor associated with aging?

Physiological decline in organ function Signup and view all the answers

Which chronic diseases impact post-mitotic tissues disproportionally in the elderly?

Many chronic diseases do not disproportionately impact post-mitotic tissues Signup and view all the answers

What are the causes of secondary sarcopenia?

Changes in caloric and protein intake Signup and view all the answers

Which factor is NOT listed as a cause of sarcopenia in the text?

Increased skeletal muscle regeneration Signup and view all the answers

How does the skeletal muscle metabolic microenvironment affect muscle function according to the text?

By directly affecting muscle function and regeneration Signup and view all the answers

Which is NOT a characteristic of primary sarcopenia according to the text?

Attributed to changes in hormone levels Signup and view all the answers

What is a significant factor affecting muscle regeneration according to the text?

Free radical oxidative damage Signup and view all the answers

What percentage of world-class records do runners in the 55-59 age group hold for the 10 km distance?

60% Signup and view all the answers

According to the information provided, what is the average decrease in arm, leg, and back strength per decade starting from the third decade?

8% Signup and view all the answers

In the context of age-related powerlifting records, which statement is true?

Strength records peak in the later decades. Signup and view all the answers

What is the term used to describe the minimum functional unit of neural control of muscle contraction?

Motor unit Signup and view all the answers

Based on the information provided, what factor contributes most to the decrease in strength with age?

Muscle atrophy Signup and view all the answers

What is the correlation coefficient between leg extensor power and walking speed in old men and women according to the provided data?

$R = 0.95$ Signup and view all the answers

Which type of muscle fibres preferentially atrophy with aging?

Fast twitch (Type 2A oxidative glycolytic) fibres Signup and view all the answers

What does an increased proportion of type 1 muscle fibres suggest in relation to aging?

Decreased muscle power Signup and view all the answers

What is the main characteristic of sarcopenia?

Loss in the number and size of type 2 muscle fibres Signup and view all the answers