Flashcards in Chapter 2 Deck (102):
Muscle strength is determined by?
1. Cross sectional area
2. Coordinated activation of muscle cells
What are Primary tissue types?
types of muscles
Where do you find smooth muscles ?
Skeletal Muscle is
Smooth or striated?
what is the name of the connective tissue surrounding Skeletal Muscles?
fascia or perimysium
What is the smallest compartment of skeletal muscle called ?
Fasciculus which contains a number of muscle fibers
Which heals faster ?
Tendon or muscle
Muscle fibers are in what orientation to each other ?
Blood vessels location in a muscle
Blood vessels are wrapped in CT and are generally paralleled to fibers
Capillaries location in muscle
Run between fibers
Which type of contraction can limit blood flow?
Dynamic or Isometric
What is the muscular NT
Muscle cell fibers contain
Muscle color is due to
Myoglobin is a
Myofibrils are surrounded by
Smallest contractile unit of a muscle fiber
Myofibril is a chain of
Sarcomeres laid end to end
The sarcomere has ------that keep contractile and regulatory proteins in the correct arrangement
Muscle fiber filled with
Striated appearance is due to
Cross banding of myofibrils
A band is
I band is
Name proteins that are involved in force transmission to the enomysium
Actomysin helps in
Mechanism of muscle contraction
Nerve impulse excitation, which releases calcium ( from SR) into the sarcoplasm and causes contraction of the filament array
Each thick filaments in the muscle fibers has ------myosin molecules
Mechanism of contraction
H zone disappears
Distance reduced between successive z lines
Filaments maintain their length ( do not shorten)
Thin filaments slide past thick, thus increasing their overlap
How many sarcomeres per cm of muscle fiber
Contraction speed depends on
1. Rate of myosin heads attaching, rotating and detaching
2. Muscle length
Isometric force is related to
Force is inversely related to
velocity of shortening
What is a power stroke?
When activated myosin heads now bind to the actin as the myosin head changes shape to bent, which causes the head to pull on the thin filaments
ADP and P are released from
What is a motor unit?
group of muscle fibers that are functionally united
Small motor units are for
Finely controlled muscles
Larger motor units are for
Contraction force depends on
1. # of motor units simultaneously activated
2. Cross sectional area of the muscles
What is major difference in fiber types ?
speed of contraction
Speed of contraction
Type I 80-100 ms
Speed of contraction
Types of fibers
Type I ( red , Fatigue resistant)
II a ( red,Fatigue resistant )
II X ( White , fatiguable)
Does fiber type IIx have more contracting power or type I
Type IIx has 3X greater contracting power
Type IIx has more or fewer mitochondria ?
Type IIx has more or less capillary supply?
Less or poorer
Type IIx has -----stores of glycogen and phosphocreatine
Type IIx fibers have
High activity of glycogenolytic and glycolytic enzymes
Type IIx fibers in terms of contraction?
Powerful contractions for brief periods
These kind of fibers have fast acting ATPases
II a and IIx
These kinds of fibers have oxidative capacity
IIa and type I
What type of neurons in type I fiber?
Slow conduction velocity
Low activation threshold
What type of neurons in Type II fibers
Fast conducting velocity
Higher activation threshold
Large motor units have what type of fibers
Small motor units have what type of fiber
Small/slow Motor units are used for
Fast motor units are used for
In old age humans this type of fiber atrophy quicker
How does training affect the proportions of fiber types
Doesn't significantly affect it buy
Can affect the diameter specially type II
3 types of muscle contractions
High force eccentric contraction is also called
Delayed onset muscle soreness
Reasons for DOMS
Small # of fibers activated
Type II fibers may be selectively recruited ?
High load on few fibers--> ruptures of the fibers
Skeletal muscle adaptability to strength training
(Muscle gets bigger )
Hypertrophic responses cause
Greater anaerobic capacity
Gradual hypertrophy occurs because of
Increased fiber diameter NOT increased fiber number
Does proportion of different fiber types change in hypertrophy?
The -----content of tissues give them their shape
Enzyme content determines
Amount of enzyme determines
Speed of enzyme process
Side chains give proteins their
Special structure @ physiological pH
Most abundant AA in muscles
What is the most abundant free AA in muscle and plasma
Protein structure classification
Tertiary- 3D shape
Major protein storage in body
No major storage other than skeletal muscle
What happens to excess protein
Excess protein is oxidized and N excreted
Strength training induce anabolism or catabolism
Does endurance training induce anabolism
3 main purpose of protein breakdown
-Degrades damaged proteins
-AAs can be reused for synthesis of proteins and non proteins like glucose, ketones and fat
Well trained athletes have ---- post exercise turn over
Less or More?
This hormone antagonizes actions of insulin
This hormone induces liver to release somatomedins
Growth hormone is most effective in stimulating
Collagen synthesis (CT)
This hormone causes growth in bones of face, hands, feet & predisposition to diabetes
Growth hormone is not optimally effective for
Insulin stimulates -----synthesis
Health risk of testosterone
Unit of enzyme activity measurement
International Unit: IU
What is IU:
The amount of enzyme to convert one micromole of substrate to product in one minute under specified conditions
SI unit for IU
What is 1kat
The amount of enzyme that will convert 1 mole of substrate to product in 1 sec ( in optimum conditions )
Optimal temp for enzyme activity
Warmer muscles have higher
Reaction rates thus better muscle performance
What metal ions are essential for enzyme activation
Reversible binding of small molecules to the enzyme at sites other than active sites-producing a conformation change in the structure of the enzyme molecule.
Risks of taking more than needed protein >3g/day
Increased serum lipoprotein levels (arteriosclerosis risk)
95% of creatine in the body is in
2/3 is phosphocreatine
Liver and kidney can synthesize creatine from
Risks of consuming testosterone
Decrease in HDL
Inappropriate hair growth
Poor testicular function