Class 10 Science Chapter 6 MCQ

Here, all these statements are correct. Hence, your answer will be option [D].

In human beings, nervous system and endocrine system work together to control and coordinate all the activities. Both these systems consist of a number of organs that work together in a systematic way.

Junction between two neurons is called synapse. Cell Junction is a junction between neighboring cells. Neuromuscular Junction which connects nervous system to “Muscular System”.

There are two adrenal glands, one on top of each kidney that make adrenaline hormone. Testes are paired glands present in males, secretes male sex hormone. Pituitary grand is present just below the brain and is unpaired. It is also called master gland as it secretes a number of hormones. Ovaries are paired glands present in females, secretes female sex hormones.

The person having high sugar level in blood is called a “Diabetic”. Such persons are advised to take less sugar in diet, reduce weight, exercise regularly. Persons with severe diabetes (high sugar level in blood) are treated by giving injections of insulin. Pancreas secrete the hormone insulin. Its function is to regulate blood sugar level. Deficiency of insulin causes a disease known as diabetes that is characterized by large quantities of sugar in blood and even urine. Growth hormone secreted by the pituitary gland regulates growth and development of the body.

Here, all these statements are correct. Hence, your answer will be option [D].

Pituitary gland is known as “master gland” and adrenal glands are often called “glands of emergency”

During cold, mucus in nasal passage becomes too thick, so that order molecules can’t reach the olfactory receptor cells. Thus, brain receives no signal identifying the odour, and so the smell of a perfume cannot be differentiating from that of an “Agarbatti”.

Here, all these statements are correct. Hence, your answer will be option [D].

Medulla is part of hind brain. It controls the involuntary action and regulate reflex responses. The other parts of the hind brain are cerebellum and pons.

Synapses actually act like one-way valves. This is because the chemical substance is present on only one side of the gap. Due to this, the nerve impulses or messages through a particular set of neurons can go across only from one side which contains the chemical substance. In this way, synapses ensure that nerve impulses travel in only one direction through a particular set of neurons.

The movement of a plant part in response to light is called phototropism.

The pathway or route taken by nerve impulse in a reflex action is called reflex arc. Reflex arcs allowed “Rapid response”.

Tendrils are the thin thread-like groups on the stem or leaves of climbing plants. These are sensitive to touch of other parts objects (i.e. thigmotropic). When a tendril touches an object, then the site in contact with object grows slowly than its other side, (i.e. rapid cell divisions in cells that are away from the support). This causes the tendril to bend towards the object by growing towards it, wind around object and cling to it.

The shape of guard cells changes due to amount of water in them. The guard cell swell when water flows into them, causing the stomatal pore to open. Similarly, the pore closes if the guard cells shrink, due to the loss of water in them.

Adrenaline is secreted by the adrenal glands, located on top of kidneys. Growth hormone is secreted by the pituitary gland.

Iodine is necessary for the synthesis of thyroxine hormone, deficiency of it in the diet of a person produces less thyroxine hormone and causes a disease known as “goitre”. The main symptom of goitre is that the neck of the person appears to be swollen (due to the enlargement of thyroid gland situated in the neck).

A growth movement of a plant part in response to an external stimulus, towards or away from it is called tropism. Common stimuli in environment are given. Such as: Light is the type of phototropism, gravity is the type of geotropism, touch is the type of thigmotropism, chemical is a type of chemotropism, and water is a type of hydrotropism.

A receptor is a cell (or a group of cells) in a sense organ which is sensitive to a particular type of stimulus such as light, sound, etc. The common type of receptors are: i) Photoreceptors which are present in eyes detect light. ii) Gustatory receptors which are present in tongue detect taste. Iii) Olfactory receptors which are present in nose detect smell. iv) Thermo receptors which are present in skin detect heat or cold.

The statement is false as sensory neuron carry signals from receptors to spinal cord. The statement is false as motor neurons carry signals from spinal cord to effectors. The pathway taken by nerve impulse in a reflex action is called the reflex arc. A reflex action is involuntary action in response to a stimulus e.g. coughing, sneezing, etc. It follows a specific pathway as given below: Stimulus → Receptors → Spinal cord → Effector → Response