Electron microscopic studies of the sarcomeres have revealed that during muscle contraction
[A] the width of A-band remains constant
[B] the width of the H-zone increases
[C] the width of I-band increases
[D] the diameter of the fibre increases
According to the sliding filament theory
[A] actin (thin filament) moves over myosin (thick filament)
[B] myosin moves over actin
[C] both myosin and actin move on each other
Put the following statement in proper order to describe muscle contraction.
Signal sent by CNS via motor neuron.
Generation of action potential in the Sarcolemma.
Release of Ca+2 from Sarcoplasmic reticulum
The neurotransmitter acetylcholine released motorend plate.
Which of the following muscle gets into fatigue very early?
[A] Skeletal muscle
[B] Smooth muscle
[C] Cardiac muscle
Relaxation of muscle is due to the
[A] pumping of Ca+2 into Sarcoplasmic cisternae
[B] presence of ATP
[C] conformational change in troponin and masking of actin filaments
[D] both (a) and (c)
Repeated activation of the muscles can lead to accumulation of ____ due to anaerobic breakdown of glycogen in there, cause fatigue
[B] Lactic acid
[C] Citric acid
[D] Butyric acid
A neurotransmitter _____ which generates an action potential in the Sarcolemma.
[D] Acetyt choline
Which of the following statement is correct?
[A] A motor neuron along with the muscles fibres connected to it constitute a motor unit
[B] The reaction time of the fibres can vary in different muscles
[C] Muscle fatigue is due to lactic acid formation due to anaerobic respiration
The protein which maintains the muscular storage of oxygen is
Which is not a correct difference between white and red muscles fibre?
White Muscle fibre— Red muscle fibre
Less Myoglobin – 1) More myglobin
Number of mitochondria less – 2) Number of mitochondria more
Amount of Sarcoplasmic reticulum low – 3) Amount of Sarcoplasmic reticulum high
Aerobic muscle – 4) Anaerobic muscle
Skeletal system consists of
[A] framework of bone
[B] few Cartilages
Cartilage has slightly pliable matrix due to
[C] chondroitin salts
Skull is composed of
[A] cranial bones (8)
[B] facial bones (14)
The hard and protective outer covering of brain is known as
Human body contains how many ear ossciles?