Chapter 7– Control and Coordination Solutions
Question - 11 : - How does chemical coordination take place in animals?
Answer - 11 : -
Chemical coordination takes place in animalswith the help of chemical messengers called as Hormones. Hormones are thechemic fluids that are secreted by specific glands of the endocrine gland.Hormones regulate the growth, development and homeostasis of the animals.
Question - 12 : - Why is the use of iodized salt advisable?
Answer - 12 : -
Usage of Iodized salt is advisable to avoid the deficiency of Iodine. If the intake of iodine is low, the release of thyroxine from the thyroid gland will be decreased. This affects fat, carbohydrate and protein metabolism
Thus a person may have goitre problem in case if the intake of iodine is lowered.
Question - 13 : - How does our body respond when adrenaline is secreted into the blood?
Answer - 13 : -
Adrenaline hormone is secreted in large amounts when a person is frightened, or mentally disturbed. When it reaches the heart, it beats faster to supply more oxygen to our muscles. The breathing rate also increases because of the contractions of diaphragm and the rib muscles. It also raises the blood pressure, and allows more glucose to enter into the blood. All these responses together enable our body to deal with the emergency situations.
Adrenaline is a hormone secreted when a person is frightened or mentally disturbed. When Adrenaline reaches heart, heartbeat will increase to increase blood supply to our muscles. Adrenaline also increases the breathing rate because of contraction of diaphragm and the rib muscles. Adrenaline rush also increases blood pressure and allows entry of more glucose into blood. These altogether occurs when our body respond to secretion of adrenaline into our blood.
Question - 14 : - Why are some patients of diabetes treated by giving injections of insulin?
Answer - 14 : - Diabetes is a condition where insulin hormone is produced less or stopped by pancreatic cells of a person. Insulin regulates blood glucose by converting extra glucose to glycogen. When insulin is not produced adequately person blood glucose level which leads to adverse effects. In order to maintain the insulin and blood glucose level diabetes patients are treated with injections of insulin.
Question - 15 : - Which of the following is a plant hormone?
Answer - 15 : -
(a) Insulin (b) Thyroxin
(c) Oestrogen (d) Cytokinin
Answer
d) cytokinin.
Cytokinin is a plant hormone whereas Insulin, Thyroxin, Oestrogen are the hormones produced by animals.
Answer - 16 : -
(a) Dendrite.
(b) Synapse.
(c) Axon.
(d) Impulse.
Answer
(b) Synapse
Dendrite is a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.
An axon or nerve fiber is a long, slender projection of a nerve cell or neuron in vertebrates that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands.
Impulse an electrical signal that travels along axon.
Question - 17 : - The brain is responsible for
Answer - 17 : -
(a) Thinking.
(b) Regulating the heartbeat.
(c) Balancing the body.
(d) all of the above.
Answer
(d) all the above
Brain is responsible for thinking, brain regulates the heartbeat, and it balance the body.
Question - 18 : - What is the function of receptors in our body?
Answer - 18 : - Think of situations where receptors do not work properly. What problems are likely to arise?
Answer
Receptors are present throughout our body mainly sense organs. Receptors collect the information about changes that happen around us and send the signal to information to brain which render effector mechanism against the change. When receptors do not work properly, the environmental stimuli are not able to create nerve impulses and body does not respond.
Question - 19 : - Draw the structure of a neuron and explain its function.
Answer - 19 : - Neurons are nerve cells which are functional units of the nervous system. Three main parts of neurons are Dendrites, Axons and cell body.
Dendrite: Detects information and sends it to cell body
Cell Body: Maintains growth of the cell
Axon: Conducts messages away from cell body and signal to next neuron.
Question - 20 : - How does phototropism occur in plants?
Answer - 20 : - Directional movement and growth of plant in response to light is called as phototropism. Phototropism occurs due to increased auxin on the dark side and decreased auxin on the illuminated side. Because of presence of more auxin, leaf in the darker side grows faster causing it to bend towards the source of light.