Junior Intermediate - Zoology (AP and Telangana)
Very Short Answer Questions
Q: What is enterocoelom? Name the enterocoelomate phyla in the Animal Kingdom.
A: a) The body cavity formed from mesodermal pouches of archenteron
in called enterocoelic coelom or enterocoelom.
b) Enterocoelomate phyla of Animal Kingdom are Echinodermata, Hemichordata and Chordate.
Q: What are retroperitoneal organs?
A: Certain organs of the vertebrates are covered by the parietal peritoneum only on their ventral side. Such peritoneum is called
retroperitoneum and the organs lined by it are called retropritoneal organs (eg: kidneys).
Q: Distinguish between a tendon and a ligament.
A: a) Tendons attach the skeletal muscles to bones.
b) Ligament attach a bone to another at joints.
c) Tendons and ligament are formed by dense regular connective tissue.
Q: Distinguish between osteoblasts and osteoclasts.
A: a) Osteoblasts are immature bone cells that secrete organic components of matrix and also play an important role in mineralisation of bone. b) Osteoclasts are phagocytic cells involved in resorption of bone.
Q: What is the haematocrit value?
A: Percentage of total volume occupied by the red blood cells in the blood is called haematocrit value.
Q: What are intercalated discs? What is their significance?
A: a) The dark bands across the cardiac muscle are called intercalated discs.
b) Intercalated discs support synchronised contraction of cardiac muscles.
Q: What are microglia? What is their origin and add a note on their function?
A: a) Microglia are one of the types of supporting cells of nervous tissue.
b) They develop from mesoderm. c) They function as phagocytes.
Q: What is Kinety?
A: A longitudinal row of kinetosomes together with kinetodesmata constitute a unit called kinety. It lies just below the pellicle of ciliates.
Q: Distinguish between proter and opisthe.
A: a) The daughter Paramecium formed from the anterior halt of the parent is called proter.
b) The daughter Paramecium formed from the posterior half of the parent during binary fission is called opisthe.
Q: Define conjugation with reference to ciliates give two examples.
A: a) Temporary union of two senile ciliates of different mating types for the exchange of micronuclear material and nuclear neorganisation is known as conjugation.
b) Examples: Paramoecium, Vorticella.
Short Answer Questions and Answers:
Q: Explain Haversian system.
A: The matrix of bone contains Haversian canals which run parallel to the morrow cavity. They are interacted by Volkmann's canals. Blood capellaries lymph capillaries etc extend into the bone through these canals. Each Haversian canal is surrounded by many lamellae, that are arranged in concentric circles. Among the lamellae are many fluid filled spaces called lacunae. Adjacent
lacunae are inter connected by minute canaliculi. Each lacuna contains an osteocyte (inactive form of osteoblast). The cytoptasmic processes of osteocytes extend through canaliculi. A Haversian canal and the surrounding lamellae and lacunae are
collectively called a Haversian system.
Q: Describe the structure of a multipolar neuron.
A: Neurons are the functional units of nervous tissue. A neuron has a cell body (cyton, perikaryon or soma), which contains granular
cytoplasm and a spherical nucleus. Cytoplasm also contains Nissel bodies, neurofibrils, lipofuscin granules. From the periphery of cyton, many shot branched processes are formed known as dendrites.
The conduct impulses towards cyton.
A long cylindrical process arises from a region of cyton (called axon hillock) called axon or nerve fibres. Distally it is divided into many branches called axon terminals or telodendrias which end with a bulb like symaptic knobs. They contain synaptic vesicles filled with neurotransmitters. Axon transmits the impulse away from cyton to an interneuronal junction or neuromuscular junction called synapse.
In myclenated neurous, Schwann cells wrap around the internode of the axon. The layers of schwann cell contain myelin. The outer most layer that contains cytoplasm and nucleus is called neurilemma. The portions of myelenated nerve fibre devoid of myelin are called nodes of Ranvier. The part of nerve fibre between two nodes is called internode. In non myelenated neurous, nyelin sheath is absent.