1.Mention one function for each of these hormones.
i) Thyroxine
ii) Insulin
iii) Adrenaline
iv) Growth hormone
v) Testosterone.
Ans.(i) Thyroxin – Control overall metabolic rate of the body (carbohydrate, protein and fat metabolism
(ii) Insulin – Conversion of glucose to glycogen in liver and muscles, thus decreases blood glucose level.
(iii) Adrenalin – increases heart beat, blood pressure and blood glucose level.
(iv) Growth hormone – Body growth and development of bones.
(v) Testosterone – Development of male sex organ sand secondary sex characteristics like moustache, beard & voice
2.What happens at the synapse between two neurons?
Ans. The nerve impulse gets transmitted through the synapse by means of chemical signals. When a stimulus acts on the receptor, chemical reaction is set off which produces an impulse in it. This impulse travels form the dendrite of presynaptic neuron to its cell body and then along its axon. At the end of axon of this neuron, the electrical impulse releases tiny amount of a chemical substance crosses the synapse and starts a similar electrical impulse in the dendrite of the next neuron.
3.Where are Pons and medulla oblongata located? Write their functions.
Ans. Pons and medulla Oblongata are located in hind brain. Pons acts as bridge between brain and spinal cord.
Medulla oblongata – a) It is the reflex centre to control activities like salivation, swallowing, vomiting, breathing, coughing, sneezing and heart beat
b) It also controls sleeps, consciousness and activities of cerebrum
4.What are tropic movements? Name the types of tropic movements in plants.
Ans. The bending or movement of a part of plant in response to the external stimulus is called tropism or tropical movement. It is of following types.
(a) Phototropism – It is response to light. It may be towards light (positive) or away from the light (negative).
(b) Geotropism – It is response to gravity – It may be towards stimulus (positive) and away from the stimulus (negative)
(c) Chemotropism - Response to chemicals. It may be positive or negative.
(d) Hydrotropism – Response to water. It may be positive or negative.
5.What are the different kinds of neurons?
Ans. Kinds of neurons –
a) Sensory neurons – convey impulses from receptors to the main nervous system.
b) Motor neurons – carry impulses from the main nervous system to an effector.
c) Connecting (Relay) neurons – connect sensory and motor centres.
6. How are involuntary actions and reflex actions different from each other?
Ans. Difference between involuntary and reflex actions is as follows
7. Compare and contrast nervous system and hormonal control and coordination in animals
Ans
8. What is the difference between the manner in which movement’s takes place in a sensitive plant and movement in our legs?
Ans.
9. How does chemical coordination occurs in plants?
Ans. Chemical coordination in plants is maintained by plant hormones also known as phytohormones. Some of these hormones promote growth while some inhibit it. Some hormones include auxin, Gibberellins, Cytokinin etc
10. What is the role of the brain in reflex action?
Ans. A reflex action is one which we perform automatically. The sensory and motor nerves meet at a point in the spinal cord on their way to the brain. Thus the information through sensory nerves goes to the brain, where thinking process occurs. But if the reflex action is instant where thinking in not involved then the brain has no role.
11.How endocrine glands do helps in maintaining feedback control?
Ans. The timing and amount of hormones released are regulated by feedback mechanism. For example, glucose level in the blood is maintained constant (0.1%). The blood glucose levels may be maintained constantly by either of the following feedback mechanism.
a) High glucose level in the blood induces the pancreatic cells to produce insulin which converts glucose to glycogen.
b) Less glucose level in the blood do not induce the pancreateic cells to produce insulin so that less conversion of glucose to glycogen may occur.
12.Which types of glands in human body secrete hormones? State any one location for them.
Ans. There are three types of glands which secrete hormone in human body-
a) Exocrine gland – these are duct glands which do not secrete their secretion into the blood. For ex – salivary gland. it secretes salivary amylase which digest starch.
b) Endocrine – gland – These are ductless gland, and they pour their secretion in blood. For ex – Pituitary gland. It is master gland, controls most of the activities.
c) Heterocrine gland – which act as both endocrine and exocrine type of glands. For Ex Pancreas – Endocrine part produces hormone insulin and glycogen and exocrine part produce digestive enzymes
13.What are the major parts of the brain? Mention the functions of different parts
Ans. The brain is covered by a three layered system of membranes; called meninges. Cerebrospinal fluid is filled between the meninges. The CSF provides cushion to the brain against mechanical shocks. The brain is located inside the skull for maximum protection ome main structures of the human brain are explained below.
Cerebrum: The cerebrum is the largest part in the human brain. It is divided into two hemispheres; called cerebral hemispheres. Functions of cerebrum: The cerebrum controls the voluntary motor actions. It is the site of sensory perceptions; like tactile and auditory perceptions. It is the seat of learning and memory.
Hypothalamus: The hypothalamus lies at the base of the cerebrum. It controls sleep and wake cycle (circadian rhythm) of the body. It also controls the urges for eating and drinking.
Cerebellum: Cerebellum lies below the cerebrum and at the back of the whole structure. It coordinates the motor functions. When you are riding your bicycle; the perfect coordination between your pedaling and steering control is achieved by the cerebellum.
Medulla: Medulla forms the brain stem; along with the pons. It lies at the base of the brain and continues into the spinal cord. Medulla controls various involuntary functions; like hear beat, respiration, etc.
14.What are reflex actions? Give two examples. Explain a reflex arc.
Ans. The sudden involuntary movement in a voluntary organ; in response to a stimulus; is called reflex action.
Examples of reflex action:
(a) Moving your hand away from a hot iron plate
(b) Blinking of eyes
Reflex Arc: The path of electrical impulse during a reflex action is called reflex arc. A reflex arc is composed of a sensory neuron, spinal cord, motor neuron and muscle. It involves following steps: The sensory neuron picks signals from the stimulus and carries the signals to the spinal cord. Spinal cord process the signals and sends message through the motor neuron. Motor neuron transmits the signals to the effector muscle so that the muscle can take immediate action.
i) Thyroxine
ii) Insulin
iii) Adrenaline
iv) Growth hormone
v) Testosterone.
Ans.(i) Thyroxin – Control overall metabolic rate of the body (carbohydrate, protein and fat metabolism
(ii) Insulin – Conversion of glucose to glycogen in liver and muscles, thus decreases blood glucose level.
(iii) Adrenalin – increases heart beat, blood pressure and blood glucose level.
(iv) Growth hormone – Body growth and development of bones.
(v) Testosterone – Development of male sex organ sand secondary sex characteristics like moustache, beard & voice
2.What happens at the synapse between two neurons?
Ans. The nerve impulse gets transmitted through the synapse by means of chemical signals. When a stimulus acts on the receptor, chemical reaction is set off which produces an impulse in it. This impulse travels form the dendrite of presynaptic neuron to its cell body and then along its axon. At the end of axon of this neuron, the electrical impulse releases tiny amount of a chemical substance crosses the synapse and starts a similar electrical impulse in the dendrite of the next neuron.
3.Where are Pons and medulla oblongata located? Write their functions.
Ans. Pons and medulla Oblongata are located in hind brain. Pons acts as bridge between brain and spinal cord.
Medulla oblongata – a) It is the reflex centre to control activities like salivation, swallowing, vomiting, breathing, coughing, sneezing and heart beat
b) It also controls sleeps, consciousness and activities of cerebrum
4.What are tropic movements? Name the types of tropic movements in plants.
Ans. The bending or movement of a part of plant in response to the external stimulus is called tropism or tropical movement. It is of following types.
(a) Phototropism – It is response to light. It may be towards light (positive) or away from the light (negative).
(b) Geotropism – It is response to gravity – It may be towards stimulus (positive) and away from the stimulus (negative)
(c) Chemotropism - Response to chemicals. It may be positive or negative.
(d) Hydrotropism – Response to water. It may be positive or negative.
5.What are the different kinds of neurons?
Ans. Kinds of neurons –
a) Sensory neurons – convey impulses from receptors to the main nervous system.
b) Motor neurons – carry impulses from the main nervous system to an effector.
c) Connecting (Relay) neurons – connect sensory and motor centres.
6. How are involuntary actions and reflex actions different from each other?
Ans. Difference between involuntary and reflex actions is as follows
7. Compare and contrast nervous system and hormonal control and coordination in animals
Ans
8. What is the difference between the manner in which movement’s takes place in a sensitive plant and movement in our legs?
Ans.
9. How does chemical coordination occurs in plants?
Ans. Chemical coordination in plants is maintained by plant hormones also known as phytohormones. Some of these hormones promote growth while some inhibit it. Some hormones include auxin, Gibberellins, Cytokinin etc
10. What is the role of the brain in reflex action?
Ans. A reflex action is one which we perform automatically. The sensory and motor nerves meet at a point in the spinal cord on their way to the brain. Thus the information through sensory nerves goes to the brain, where thinking process occurs. But if the reflex action is instant where thinking in not involved then the brain has no role.
11.How endocrine glands do helps in maintaining feedback control?
Ans. The timing and amount of hormones released are regulated by feedback mechanism. For example, glucose level in the blood is maintained constant (0.1%). The blood glucose levels may be maintained constantly by either of the following feedback mechanism.
a) High glucose level in the blood induces the pancreatic cells to produce insulin which converts glucose to glycogen.
b) Less glucose level in the blood do not induce the pancreateic cells to produce insulin so that less conversion of glucose to glycogen may occur.
12.Which types of glands in human body secrete hormones? State any one location for them.
Ans. There are three types of glands which secrete hormone in human body-
a) Exocrine gland – these are duct glands which do not secrete their secretion into the blood. For ex – salivary gland. it secretes salivary amylase which digest starch.
b) Endocrine – gland – These are ductless gland, and they pour their secretion in blood. For ex – Pituitary gland. It is master gland, controls most of the activities.
c) Heterocrine gland – which act as both endocrine and exocrine type of glands. For Ex Pancreas – Endocrine part produces hormone insulin and glycogen and exocrine part produce digestive enzymes
13.What are the major parts of the brain? Mention the functions of different parts
Ans. The brain is covered by a three layered system of membranes; called meninges. Cerebrospinal fluid is filled between the meninges. The CSF provides cushion to the brain against mechanical shocks. The brain is located inside the skull for maximum protection ome main structures of the human brain are explained below.
Cerebrum: The cerebrum is the largest part in the human brain. It is divided into two hemispheres; called cerebral hemispheres. Functions of cerebrum: The cerebrum controls the voluntary motor actions. It is the site of sensory perceptions; like tactile and auditory perceptions. It is the seat of learning and memory.
Hypothalamus: The hypothalamus lies at the base of the cerebrum. It controls sleep and wake cycle (circadian rhythm) of the body. It also controls the urges for eating and drinking.
Cerebellum: Cerebellum lies below the cerebrum and at the back of the whole structure. It coordinates the motor functions. When you are riding your bicycle; the perfect coordination between your pedaling and steering control is achieved by the cerebellum.
Medulla: Medulla forms the brain stem; along with the pons. It lies at the base of the brain and continues into the spinal cord. Medulla controls various involuntary functions; like hear beat, respiration, etc.
14.What are reflex actions? Give two examples. Explain a reflex arc.
Ans. The sudden involuntary movement in a voluntary organ; in response to a stimulus; is called reflex action.
Examples of reflex action:
(a) Moving your hand away from a hot iron plate
(b) Blinking of eyes
Reflex Arc: The path of electrical impulse during a reflex action is called reflex arc. A reflex arc is composed of a sensory neuron, spinal cord, motor neuron and muscle. It involves following steps: The sensory neuron picks signals from the stimulus and carries the signals to the spinal cord. Spinal cord process the signals and sends message through the motor neuron. Motor neuron transmits the signals to the effector muscle so that the muscle can take immediate action.
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