Lack of relaxation between successive stimuli in sustained muscle contraction is known as
(1) fatigue
(2) tetanus
(3) tonus
(4) spasm
Sliding filament theory can be best explained as
1. when myofilaments slide pass each other actin filaments shorten while myosin filament do not shorten
2. actin and myosin filaments shorten and slide pass each other
3. actin and myosin filaments do not shorten but rather slide pass each other
4. when myofilament slide pass each other myosin filament shorten while actin filaments do not shorten
The characteristics and an example of a synovial joint in humans is
Characteristics | Examples | |
1. | Fluid cartilage between two bones, limited movements | Knee joints |
2. | Fluid filled between two joints, provides cushion | Skull bones |
3. | Fluid filled synovial cavity between two bones | Joint between atlas and axis |
4. | Lymph filled between two bones, limited movement | Gliding joint between carpals |
Which one of the following items gives its correct total number?
1. Floating ribs in humans - 4
2. Amino acids found in proteins -16
3. Types of diabetes - 3
4. Cervical vertebrae in humans - 8
Given diagram shows bone of the left human hindlimb as seen from front. It has certain mistakes in labeling. Two of the wrongly labelled bones are
(1) tibia and tarsals
(2) femur and fibula
(3) fibula and phalanges
(4) tarsals and femur
Which of the following is correct about the given figure?
(1) The length of the thick and thin myofilaments has changed.
(2) Length of both anisotropic and isotropic band has changed.
(3) The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other.
(4) Length of the sacromere remains same.
Skeletal muscles appear striated due to the presence of two characteristic proteins in alternating dark and light bands. Which of the following is a correct match of the protein with its light refractive property and color?
Protein Colour Property
(1) Myosin Light Anisotropic
(2) Actin Dark Anisotropic
(3) Myosin Dark Isotropic
(4) Actin Light Isotropic
During muscular contraction, which of the following events occur?
(i) H-zone disappears
(ii) A band widens
(iii) I band shortens
(iv) Width of A band is unaffected
(v) M line and Z line come closer
(1) (i),(iii),(iv) and (v)
(2) (i),(ii) and (v)
(3) (ii),(iv) and (v)
(4) (i),(ii) and (iii).
The H-Zone in the skeletal muscle fibre is due to
(1) the central gap between actin filaments extending through myosin filaments in the A-band
(2) extension of myosin filaments in the central portion of the A-band
(3) the absence of myofibrils in the central portion of A-band
(4) the central gap between myosin filaments in the A-band
Consider the diagram given below.
Parts labelled as A, B, C, D, E and F respectively indicate.
(1) Sacrum, ilium, pubis, femur, tibia and fibula
(2) Ilium, pubis, sacrum, femur, fibula and tibia
(3) Sacrum, pubis, ilium, femur, tibia and fibula
(4) Ilium, sacrum, pubis, femur, tibia and fibula