Q&A - Ask Doubts and Get Answers

Sort by :
Clear All

9. Name the type of joint between the following:-

            (a) atlas/axis

   (a) atlas/axis possess pivotal joint  

8.  How do you distinguish between a skeletal muscle and a cardiac muscle ?

The differences between skeletal muscles and cardiac muscles are as follows:  Skeletal muscle Cardiac muscle  The function of skeletal muscles is voluntary. Cardiac muscles function involuntarily. The cells of these muscles are unbranched The cells of these muscles are branched INtercalated discs between the cells are absent Intercalated discs between the cells are present These...

7.    What are the different types of movements exhibited by the cells of human body

The different types of movements exhibited by the cells of the human body are as follows:  1. Amoeboid movement - The leucocytes present in the blood show amoeboid movement. During tissue damage, these blood cells move in an amoeboid manner (by forming temporary pseudopodia)  from the circulatory system towards the site of injury to initiate an Immune response. 2. Ciliary movement- The...

6.  Match Column I with Column II :

            Column I                       Column II
            (a) Smooth muscle       (i) Myoglobin
            (b) Tropomyosin           (ii) Thin filament
            (c) Red muscle             (iii) Sutures
            (d) Skull                        (iv) Involuntary

The correct matching is as follows: a- iv, b- ii, c- i, d- iii               Column I                       Column II             (a) Smooth muscle        (iv) Involuntary             (b) Tropomyosin            (ii) Thin filament             (c) Red muscle              (i) Myoglobin             (d) Skull                         (iii) Sutures

5. Write the difference between :

            (c) Pectoral and Pelvic girdle

Pectoral girdle Pelvic girdle Skeletal support where forelimbs are attached Askeletal support where hindlimbs are attached It includes two bones i.e. clavicle and scapula It includes three bones i.e.ileum, pubis and ischium  

 5. Write the difference between :

            (b) Red and White muscles

Red muscle fibre White muscle fibre These are thin and smaller in size These are thick and larger in size Due to the presence of myoglobin, they are red in colour                Due to the presence of only a small amount of myoglobin, they are white in colour These carry out slow and sustained contractions These carry out fast contractions for shorter durations.   

5.  Write the difference between :

             (a) Actin and Myosin

The differences between actin and myosin are as follows: Actin  Myosin Actin refers to the thin contractile protein Myosin refers to the thick contractile protein Actin is found in light bands called isotropic bands Myosin is found in dark bands called anisotropic bands  

 4.     Write true or false. If false change the statement so that it is true.

             (a) Actin is present in thin filament
             (b) H-zone of striated muscle fibre represents both thick and thin filaments.
             (c) Human skeleton has 206 bones.
             (d) There are 11 pairs of ribs in man.
             (e) Sternum is present on the ventral side of the body.

 (a) Actin is present in thin filament   True statement   (b) H-zone of striated muscle fibre represents both thick and thin filaments. False statement. H -zone of striated muscle fibre is the central part of the thick filament that is not overlapped by the thin filament.              (c) Human skeleton has 206 bones   True statement.             (d) There are 11 pairs of ribs in man.  False...

3. Describe the important steps in muscle contraction.

The process of muscle contraction includes the following events 

1. Depolarisation of Sarcolemma- In this event, a signal is sent by the central nervous system through a motor neuron and it reaches the neuromuscular junction or motor end plate. The neuromuscular junction refers to the junction between a motor neuron and the sarcolemma of the muscle fibre. The receiving of the signal by neuromuscular junction causes the acetylcholine which is a neurotransmitter to release and set the action potential in the sarcolemma.

2. Release of Calcium Ions- This step includes the transmission of the action potential by sarcolemma to the sarcoplasmic reticulum to release calcium ions in the sarcoplasm.

3. Conformational Changes in Actin Filaments- The calcium ions thus released binds to the troponin and tropomyosin on active filaments changing the three-dimensional shape of the actin–troponin-tropomyosin complex. This causes the active site for myosin which is found on the actin filament to be exposed. 

4. Activation of Myosin Heads- Later on, the myosin heads also get activated and they release energy by the hydrolysis of ATP resulting in the binding of myosin heads to the active sites present on the actin filaments. This leads to the formation of actin-myosin cross-bridge.

5. Sliding of Actin Filaments over Myosin- After the formation of cross-bridges, the myosin head rotates to pull the actin filament towards the centre of the A-band, i.e. the H-zone. The Z-line attached to the actin filaments is also pulled inwards resulting in the contraction of the sarcomere. During contraction, the I-band shortens, while the A-band retains its length. This causes the muscles to contract. 

View More

2. Define sliding filament theory of muscle contraction.

Sliding filament theory of muscle contraction 1.The sliding filament theory was mainly proposed to explain the process of muscle contraction. This theory proposes that during muscle contraction the thin filaments slide over the thick filaments leading to shortening of the myofibrils. 2. Each muscle fibre possesses alternate light and dark bands, which contains a specialised contractile protein...

 1.     Draw the diagram of a sarcomere of skeletal muscle showing different regions.

Q9.    Match the following:

Column I

Column II

(a) T4

(i) Hypothalamus

(b) PTH

(ii) Thyroid

(c) GnRH

(iii) Pituitary

(d) LH

(iv) Parathyroid

Column I Column II (a)     T4 (ii) Thyroid (b)     PTH (iv) Parathyroid (c)      GnRH (i) Hypothalamus (d)     LH (iii) Pituitary

Q8.    Briefly mention the mechanism of action of FSH.

Follicle-stimulating hormone (FSH) is a glycoprotein polypeptide hormone. It is insoluble in lipid and hence cannot enter the target cell. This hormone binds to the cell surface and activates cellular systems to perform functions. Steps in action of FSH: A molecule of FSH binds on the receptor protein present on the cell surface and forms the hormone-receptor complex. Formation of...

Q7.    Which hormonal deficiency is responsible for the following:

          (c) Cretinism

Insufficient secretion of thyroxine is responsible.

Q7.    Which hormonal deficiency is responsible for the following:

          (b) Goitre

Insufficient secretion of thyroxin is responsible.

Q7.    Which hormonal deficiency is responsible for the following:

          (a) Diabetes mellitus

Insufficient secretion of insulin is responsible.

Q6.    Give example(s) of:

          (f) Androgens and estrogens

Androgens : Testosterone and androsterone Estrogens : β-oestradiol

Q6.    Give example(s) of:

          (e) Blood pressure lowering hormone

Atrial natriuretic factor 

Q6.    Give example(s) of:

          (d) Progestational hormone


Q6.    Give example(s) of:

          (c) Gonadotrophic hormones

Luteinising hormone (LH) Follicle-stimulating hormone (FSH)