BIOLOGY M.C.Q (1 Marks)

Statement $I$: The cerebral hemispheres are connected by nerve tract known as corpus callosum.

Statement $II$: The brain stem consists of the medulla oblongata, pons and cerebrum.

In the light of the above statements, choose the most appropriate answer from the options given below:

Choose the correct answer from the options given below :

$R$ : Ionic channels are absent in the area covered by myelin sheath therefore, depolarization occurs only at the nodes of Ranvier, resulting in saltatory or jumping conduction.

$II.$ The neural system provides an organized network of point to point connection for a quick coordination.

$III.$ The neural organization is very complex in lower invertebrates.

$IV.$ The human neural system includes $CNS$ and $PNS$

Select the correct statements.

$(a)$. Balance of the body

$(b)$. Circadian rhythm of the body

$(c)$. Human behaviour

$(d)$. Functioning of heart and kidneys
 

$I.$ thermoregulation

$II.$ regulation of sexual behavior

$III.$ expression of emotional reactions (e.g., excitement, pleasure, rage and fear)

$IV.$ memory

Choose the correct option

$I.$ The medulla is connected to the spinal cord

$II.$ Medulla contains controlling centres for respiration, cardiovascular reflexes and gastric secretion

$III.$ Cerebellum has very convoluted surface in order to provide the additional space for more neurons

$(I)$. It consists of grey matter

$(II)$. It shows prominent folds

$(III)$. It consists of white matter

$(IV)$. It contains motor areas, sensory areas and association areas Codes

$(I)$. Located between the thalamus/hypothalamus

$(II)$. Has a canal named cerebral aqueduct passes through

$(III)$. Dorsal part consists of $4$ lobes

Choose the correct option

Here, $A$ and $B$ refer to

$a.$ Memory

$b.$ Communication

$c.$ Blood pressure

$I.$ Urge for eating and drinking

$II.$ Body temperature

$III.$ Hormones production that regulates the secretion of pituitary gland.

$IV.$ Creative thinking and consciousness.

$I.$ The medulla is connected to the spinal cord.

$II.$ Medulla contains controlling centers for respiration, cardiovascular reflexes and gastric secretion.

$III.$ Cerebellum has very convoluted surface in order to provide the additional space for more neurons.

$I.$ Pre and postsynaptic membrane neurons are in very close proximity at electric synapse

$II.$ Electric current are involved in the transmission of impulses

$III.$ Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon

$IV.$ Impulse transmission is always faster in electric synapse than that across a chemical synapse

$V.$ Electrical synapses are rare in our system

The correct option is

$(I)$. pre and postsynaptic neurons are in very close proximity

$(II)$. pre and postsynaptic neurons are separated by synaptic cleft

$(III)$. impulse transmission is very fast

$(IV)$. electrical synapses are common in our system

Select the correct option

$R$ : Influx of sodium ion during nerve impulse generation is due to efflux of potassium ions.

$I.$ The polarity of the membrane at site $A$ is reversed and depolarized, i.e., the outer surface becomes negatively charged and the innerside becomes positively charged, generating nerve impulse

$II$. A stimulus causes disturbance to the membrane at site of $A$ nerve fibre resulting in leakage of $N a^{+i i}$ ions inside the nerve fibre

$III.$ On the outer surface, current flows from site $B$ to site $A$ to complete the circuit of current flow. Hence, the polarity at the site is reversed, and an action potential is generated at site $B.$ The impulse (action potential) generated at site $A$ arrives at site $B .$ The sequence is repeated along the length of the axon and consequently the impulse is conducted

$IV.$ Immediately ahead, the axon $(e \cdot g .$, site $B )$ membrane has a positive charge on the outer surface and a negative charge on its inner surface. As a result, a current flows on the inner surface from site $A$ to site $B$

$(I)$. Open $N a^{+i i}$ channel

$(II)$. Closed $N a^{+i i}$ channel

$(III)$. Closed $K^{+i i}$ channel

$(IV)$. Open $K^{+i i}$ channel

$(a)$.Cell body     $(b)$. Axon   $(c)$. Dendrites    $(d)$. Glial cells

$I$. Dendrites are long fibre, with branched distal end

$II$. Axons are short fibres which arise from the cell body

$III$. Cell body of a neuron contains cytoplasm, nucleus with cell organelles and Nissl's granules

$IV$. The dendrites transmits nerve impulses away from the cell body to a synapse

The correct option is

$(I)$. Each neuron has a cell body

$(II)$. Each neuron has a single axon

$(III)$. Neurons are the functional units of nervous system

Select the correct option

 $\begin{array}{|p{0.3\linewidth}|p{0.6\linewidth}|} \hline Column\,\,-I & Column\,\,-II   \\ \hline 1.\,\,Cell\,\,body & p.\,\,Transmit\,\,impulses\,\,towords\,\,the\,\,cell\,\,body \\ \hline 2.\,\,Dendrites & q.\,\,Transmit\,\,impulses\,\,away\,\,from\,\,the\,\,cell\,\,body \\ \hline 3.\,\,Synaptic\,\,vesicles & r.\,\,Contain\,\,Cytoplasm\,\,and\,\,granular\,\,bodies  \\ \hline  & s.\,\,Neurotransmitters   \\ \hline \end{array}$

Part $-$ Function