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Receptor : - All information from our environment is detected by the specialised tips of some nerve cells which are called receptors.
These receptors are usually located in our sense organs, such as the ear, the nose, the tongue, the skin and the eye.
These receptors are usually located in our sense organs, such as the ear, the nose, the tongue, the skin and the eye.
Nervous System : Nervous tissue is made up of an organized network of nerve cells, or neurons, and transmits information through electrical impulses from one part of the body to another.
These receptors are usually located in our sense organs, such as the ear, the nose, the tongue, the skin and the eye.
Nervous System : Nervous tissue is made up of an organized network of nerve cells, or neurons, and transmits information through electrical impulses from one part of the body to another.
Nerve cell (neuron) is the structural and functional unit of the nervous system.
The neuron has three parts.
1. Dendrites - These are branched protoplasmic extension of cell body. Information is received /acquired through dendrites.
2. Cell body- It has a well defined nucleus and other cell organelles. The information received by the dendrite in the cell body travels in the form of electrical impulse
3. Axon- It is a long structure of the cell body. It transmits the electrical impulse of information from the cell body to the dendrite of next neuron. At the end of the axon, the electrical impulse releases of some chemicals. These chemicals cross the gap, or synapse and generate electrical impulse in a dendrite of the next neuron Synapse ( Synaptic Cleft) :- The gap between the end of the axon of one neuron and the dendrite of the next neuron is called synapse
2. Cell body- It has a well defined nucleus and other cell organelles. The information received by the dendrite in the cell body travels in the form of electrical impulse
3. Axon- It is a long structure of the cell body. It transmits the electrical impulse of information from the cell body to the dendrite of next neuron. At the end of the axon, the electrical impulse releases of some chemicals. These chemicals cross the gap, or synapse and generate electrical impulse in a dendrite of the next neuron Synapse ( Synaptic Cleft) :- The gap between the end of the axon of one neuron and the dendrite of the next neuron is called synapse
The transmission of a nerve impulse
The information, acquired at the end of the dendritic tip of neuron and creates an electrical impulse. This impulse travels from the dendrite to the cell body, and then along the axon to its end. At the end of the axon, the electrical impulse releases of some chemicals. These chemicals cross the gap, or synapse and generate electrical impulse in a dendrite of the next neuron. Synapse finally allows delivery of such impulses from neurons to other cells.
Reflex action: A sudden, quick and immediate response to a stimulus is called a reflex action.
Example:
1. Immediate withdrawal of the hand after touching a hot object.
2. Opening of the mouth on suddenly hearing a loud sound.
3. Sneezing and coughing.
4. Secretion of saliva on seeing good food.
5. Constriction of eyes on sudden bright light.
Reflex arc: The pathway through which stimuli reach the spinal cord from the affected organ and the signals generated from there reach back to the affected organ is called the "reflex arc".
Reflex arc are made between the input nerve and the output nerve.
Reflex arcs are in the spinal cord itself.
Brain : The brain is the main coordination center of the body which is protected by the skull.
The brain is located in a box of bones (skull). The fluid filled balloon inside the box contains the brain which acts as a shock absorber.
The brain has three major parts
1. Fore-brain -The fore-brain is the main thinking part of the brain. It has regions which receive sensory impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight.
Hypothalamus, a part of the fore brain which controls our hunger, thirst, hatred, love, etc.
2. Mid-brain- This part of the brain is located between the fore brain and hind brain. It is responsible for vision and hearing.
3. Hind-brain -It has two parts
(i) Cerebellum- Cerebellum controls voluntary actions like walking in a straight line, riding a bicycle, picking up a pencil etc. It is responsible for maintaining the posture and balance of the body.
(ii) Medulla oblongata - This is the last part of the brain which is connected to the spinal cord. All involuntary actions like heartbeat, blood pressure, salivation and vomiting are controlled by the medulla oblongata located in the hindbrain.
1. Central nervous system- The brain and spinal cord form the central nervous system.
2. Peripheral nervous system – Peripheral nervous system made up of cranial nerves arising from the brain and spinal nerves arising from the spinal cord.
The communication between the central nervous system and the other parts of the body is facilitated by the peripheral nervous system
The spinal cord is protected by the vertebral column or backbone.
Voluntary actions:- Those actions over which we have control are called voluntary actions. Voluntary actions are controlled by the forebrain. Example: speaking, writing, moving a chair, clapping
Involuntary actions: Those actions over which we do not have control are called involuntary actions. Involuntary actions are controlled by the hindbrain (medulla oblongata). Such as heart beat, blood pressure, salivation and vomiting, breathe or digest food
Coordination in plants
Plants show two different types of movements, one dependent on growth and the other independent of growth.
Immediate Response to Stimulus
When we touch the leaves of a chhui-mui they begin to fold up and bend down. The shrinking of the leaves of the chhui-mui is not related to growth. Mimosa leaves move very Rapidly in response to touch
Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking
Movement Due to Growth
The pea plant climb up other plants or fences with the help of tendrils. These tendrils are sensitive to touch. When they come in contact with any support, the part of the tendril which is away from the object grows faster than the part near the object, due to which the tendril wraps around the object. This growth is directional, it appears as if the plant is moving.
Phototropism: Movement of plant shoots towards light is called phototropism.
Plant shoots show positive phototropism towards light and roots show negative phototropism towards light.
Geotropism : The roots of a plant always grow downwards while the shoots usually grow upwards. This upward and downward growth of shoots and roots, respectively, in response to the pull of earth or gravity is, geotropism
Hydropathy: Movement of roots toward water.
Chemotropism - The growth of pollen tubes towards ovules.
limits of electrical impulse
Electrical impulses can reach only those cells that are connected to the nervous system, not each and every cell
once an electrical impulse is generated in a cell and transmitted, the cell will take some time to reset its mechanisms before it can generate and transmit a new impulse. Therefore the cell cannot generate impulses continuously.
Thus the most multicellular organisms use another means of communication between cells, namely, chemical communication.
These compounds, are hormones used by multicellular organisms for control and coordination
Plant hormone
Plant hormones help coordinate growth, development and response to the environment. The place of their synthesis is away from their area of action and they reach the area of action by simple diffusion.
1. Auxin:- It is synthesized in the tip of the shoot and helps in increasing the length of cells. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot.
The concentration of auxin on the side of the shoot away from light stimulates the cells to grow in length. Hence the plant appears to be turning towards the light.
2. Gibberellin:- It helps in the growth of the stem.
3. Cytokinin:- It stimulates cell division. It is found in large quantities in fruits and seeds.
4. Abscisic acid :- This is a growth inhibiting hormone. Withering of leaves is the effect of this hormone.
Animal hormones
The recovery mechanism controls the action of hormones.
1. Adrenaline hormone:- Adrenaline hormone is secreted from the adrenal gland.
Adrenaline is secreted directly into the blood and is carried to different parts of the body.
This hormone increases the heartbeat resulting in supply of more oxygen to our muscles.
The blood supply to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs.
It directs blood towards our skeletal muscles.
The breathing rate also increases due to contraction of the diaphragm and rib muscles.
All these responses together enable the animal body to deal with the crisis situation.
2. Thyroxine hormone:- Thyroxine hormone is secreted bythe thyroid gland. Iodine is necessary for the thyroid gland to make thyroxin hormone. hyroxin regulates carbohydrate, protein and fat metabolism in the body to provide the perfect balance for growth. If there is a deficiency of iodine in our diet then we might suffer from goiter. A symptom of this disease is a swollen neck.
Reflex action: A sudden, quick and immediate response to a stimulus is called a reflex action.
Example:
1. Immediate withdrawal of the hand after touching a hot object.
2. Opening of the mouth on suddenly hearing a loud sound.
3. Sneezing and coughing.
4. Secretion of saliva on seeing good food.
5. Constriction of eyes on sudden bright light.
Reflex arc: The pathway through which stimuli reach the spinal cord from the affected organ and the signals generated from there reach back to the affected organ is called the "reflex arc".
Reflex arc are made between the input nerve and the output nerve.
Reflex arcs are in the spinal cord itself.
Brain : The brain is the main coordination center of the body which is protected by the skull.
The brain is located in a box of bones (skull). The fluid filled balloon inside the box contains the brain which acts as a shock absorber.
The brain has three major parts
1. Fore-brain -The fore-brain is the main thinking part of the brain. It has regions which receive sensory impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight.
Hypothalamus, a part of the fore brain which controls our hunger, thirst, hatred, love, etc.
2. Mid-brain- This part of the brain is located between the fore brain and hind brain. It is responsible for vision and hearing.
3. Hind-brain -It has two parts
(i) Cerebellum- Cerebellum controls voluntary actions like walking in a straight line, riding a bicycle, picking up a pencil etc. It is responsible for maintaining the posture and balance of the body.
(ii) Medulla oblongata - This is the last part of the brain which is connected to the spinal cord. All involuntary actions like heartbeat, blood pressure, salivation and vomiting are controlled by the medulla oblongata located in the hindbrain.
1. Central nervous system- The brain and spinal cord form the central nervous system.
2. Peripheral nervous system – Peripheral nervous system made up of cranial nerves arising from the brain and spinal nerves arising from the spinal cord.
The communication between the central nervous system and the other parts of the body is facilitated by the peripheral nervous system
The spinal cord is protected by the vertebral column or backbone.
Voluntary actions:- Those actions over which we have control are called voluntary actions. Voluntary actions are controlled by the forebrain. Example: speaking, writing, moving a chair, clapping
Involuntary actions: Those actions over which we do not have control are called involuntary actions. Involuntary actions are controlled by the hindbrain (medulla oblongata). Such as heart beat, blood pressure, salivation and vomiting, breathe or digest food
Coordination in plants
Plants show two different types of movements, one dependent on growth and the other independent of growth.
Immediate Response to Stimulus
When we touch the leaves of a chhui-mui they begin to fold up and bend down. The shrinking of the leaves of the chhui-mui is not related to growth. Mimosa leaves move very Rapidly in response to touch
Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking
Movement Due to Growth
The pea plant climb up other plants or fences with the help of tendrils. These tendrils are sensitive to touch. When they come in contact with any support, the part of the tendril which is away from the object grows faster than the part near the object, due to which the tendril wraps around the object. This growth is directional, it appears as if the plant is moving.
Phototropism: Movement of plant shoots towards light is called phototropism.
Plant shoots show positive phototropism towards light and roots show negative phototropism towards light.
Geotropism : The roots of a plant always grow downwards while the shoots usually grow upwards. This upward and downward growth of shoots and roots, respectively, in response to the pull of earth or gravity is, geotropism
Hydropathy: Movement of roots toward water.
Chemotropism - The growth of pollen tubes towards ovules.
limits of electrical impulse
Electrical impulses can reach only those cells that are connected to the nervous system, not each and every cell
once an electrical impulse is generated in a cell and transmitted, the cell will take some time to reset its mechanisms before it can generate and transmit a new impulse. Therefore the cell cannot generate impulses continuously.
Thus the most multicellular organisms use another means of communication between cells, namely, chemical communication.
These compounds, are hormones used by multicellular organisms for control and coordination
Plant hormone
Plant hormones help coordinate growth, development and response to the environment. The place of their synthesis is away from their area of action and they reach the area of action by simple diffusion.
1. Auxin:- It is synthesized in the tip of the shoot and helps in increasing the length of cells. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot.
The concentration of auxin on the side of the shoot away from light stimulates the cells to grow in length. Hence the plant appears to be turning towards the light.
2. Gibberellin:- It helps in the growth of the stem.
3. Cytokinin:- It stimulates cell division. It is found in large quantities in fruits and seeds.
4. Abscisic acid :- This is a growth inhibiting hormone. Withering of leaves is the effect of this hormone.
Animal hormones
The recovery mechanism controls the action of hormones.
1. Adrenaline hormone:- Adrenaline hormone is secreted from the adrenal gland.
Adrenaline is secreted directly into the blood and is carried to different parts of the body.
This hormone increases the heartbeat resulting in supply of more oxygen to our muscles.
The blood supply to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs.
It directs blood towards our skeletal muscles.
The breathing rate also increases due to contraction of the diaphragm and rib muscles.
All these responses together enable the animal body to deal with the crisis situation.
2. Thyroxine hormone:- Thyroxine hormone is secreted bythe thyroid gland. Iodine is necessary for the thyroid gland to make thyroxin hormone. hyroxin regulates carbohydrate, protein and fat metabolism in the body to provide the perfect balance for growth. If there is a deficiency of iodine in our diet then we might suffer from goiter. A symptom of this disease is a swollen neck.
3. Growth Hormone – Growth hormone is secreted by the pituitary gland. Growth hormone regulates the growth and development of the body. If there is deficiency of this hormone in childhood then it causes dwarfism.
4. Testosterone - It is a male hormone which is secreted by the testicles.
5. Estrogen - It is a female hormone secreted by the ovaries which regulates the development of female sexual organs and the menstrual cycle.
6. Insulin – Insulin hormone is secreted by the pancreas which helps in regulating the sugar level in the blood. If it is not secreted in proper amounts the sugar level in the blood increases which leads to diabetes.
- Which part of the nervous system controls reflex arcs?
Spinal cord. - Which part of the brain maintains body position and balance?
The cerebellum maintains body position and balance. - Which is the main thinking part of the brain?
fore brain - How is spinal cord protected?
Vertebral column made by vertebral protects the backbone. - Name two tissues that provide control and coordination in multicellular animals.
(i) Nervous tissue (ii) muscular tissue. - Name the sensory receptors found in the nose and on the tongue. ?
Olfactory receptors, gustatory receptors. - Iodine is necessary for the synthesis of which hormone?
Thyroxine - Name the endocrine gland associated with brain. ?
Pituitary gland - Which gland secretes growth hormone in human beings ?
Pituitary gland. - Name the hormone which is injected to a diabetic patient. ?
Insulin - Which hormone is secreted during emergency situations like anger or excitement ?
Adrenaline is secreted during emergency situations. - Name the endocrine gland associated with kidneys. ?
Adrenal gland - Name the hormone which is secreted by the adrenal gland. ?
Adrenaline. - At the time of puberty, both boys and girls show lots of changes in appearance. Name the hormones responsible for these changes. ?Testosterone in male and oestrogen in females.
- Which hormone is responsible for changes in females during puberty?
Oestrogen - Which endocrine gland is present in males but not in females?
Testes - Which hormone regulates the development of female sexual organs and the menstrual cycle ?
Oestrogen - Which gland secretes digestive enzymes as well as hormone?
Pancreas - Name two specialised tissues that provide control and coordination in multicellular organisms. ?
Nervous and muscular tissues. - Name the diseases by which a person is likely to suffer due to the deficiency of: (i) iodine (ii) insulin
(i) Goitre (ii) Diabetes. - Which mechanism control timing and amount of hormone released?
Feedback mechan - Name the plant hormone responsible for the elongation of cells?
Auxin - Name the plant hormone responsible for the promotion of cell division. ?
Cytokinin. - Name the parts of the neuron where: a. information is acquired. b. impulse must be converted into a chemical signal for onward transmission?
(a) Dendrites (b) End of axon. - What will happen to a plant shoot if sunlight falls on it from one direction only? What do you call this movement?
Plant shoot will bend towards light. This movement is called phototropism. - Write the role of motor areas in brain.?
Motor areas of the brain control the movement of voluntary muscles. - Give the functions of cerebellum. ?It is responsible for maintaining the posture and balance of the body.
- Name the components of central nervous system.?
The components of central nervous system are: (i) Brain (ii) Spinal cord. - Which system facilitates the communication between central nervous system and other parts of the body?Peripheral nervous system
- Define‘Chemotropism’. Give one example. ?
The movement of plant organ toward a chemical stimulus is called chemotropism.
Example : The growth of pollen tubes towards ovules. - What is meant by hydrotropism? Give an example. ?
The Movement of plant part (roots) towards the water is called hydrotropism
The roots of plants show positive hydrotropism - Define phototropism and give one example. ?
Movement of plant parts towards the light is called phototropism,
Plant shoots show positive phototropism towards light - What is synapse ?
The gap between the end of the axon of one neuron and the dendrite of the next neuron is called synapse. - Define ‘reflex action’ ?
A sudden, quick and immediate response to an external stimulus is called a reflex action. - Trace the sequences of events through a reflex arc which occur when a bright light is focused on your eyes.
Photo Receptor(Eye) —> Sensory neuron —> Spinal cord —> Motor neuron —> Eye muscles —> Effector. - Write the name of a growth inhibiting plant hormone. Write its one more function.
Abscisic acid
It promotes the wilting and falling of leaves. - All information for our environment is detected by specialised tips of some nerve cells. Write the name given to such tips and also mention where are they located?
Receptors. They are located in sense organs such as the ear, the nose, the tongue, the skin and the eye - State the function of :
(i) Gustatory receptors - To detect taste.
(ii) Olfactory receptors - To detect smell. - List two different functions performed by pancreas in our body.
(i) Pancreas secretes insulin hormones which regulates blood sugar level.
(ii) Pancreas secretes pancreatic juice which helps in digestion food. - Pancreas helps in digestion and also regulates blood sugar level. Explain.
Pancreas secretes pancreatic juice as well as a hormone called as insulin. Pancreatic juice helps in digestion whereas insulin regulates blood sugar level. - Why should we use iodised salt in our diet?
Iodine is necessary for the thyroid gland to production of thyroxine hormone.Thyroxine regulates carbohydrates, proteins and fat metabolism in the body, to provide best balance for growth. - Pituitary is often termed as master endocrine gland. Why ?
Pituitary is called as master endocrine gland because it controls and coordinates the secretion of all the other endocrine glands. - If iodine is insufficient in one’s diet, what might be the deficiency disease and its symptoms?
If iodine is insufficient in one’s diet, iodine deficiency disease called goitre occurs. A symptom of this disease is a swollen neck. - What are hormones?
Hormones are the chemical substances secreted in trace amounts by endocrine glands. - How do muscle cells move?
The muscle cells move by changing their shape. Muscle cells have special proteins that change their shape and arrangement in the cell in response to electrical impulse. - What are the components of reflex arc?
1. Stimulus 2. Receptors 3. Sensory neurons 4. Spinal cord 5. Motor neurons 6. Effector. - How is nerve impulses get transmitted across the synapse?The nerve impulse get transmitted across the synapse by the help of chemical substance (neuro-transmitter).
- An old man is advised by his doctor to take less sugar in his diet. Name the disease from which the man is suffering. Mention the hormone due to imbalance of which he is suffering from this disease. Which endocrine gland secretes this hormone?
The man is suffering with the disease Diabetes. Insulin is the hormone which is responsible for this disease. Pancreas secretes this hormone. - List two body functions that will be affected if cerebellum gets damaged.
(i) Walking in a straight line.
(ii) Picking up a thing from the ground. - Name the part of brain which controls (i) voluntary action, (ii) involuntary action.
(i)Voluntary actions - Cerebellum;
(ii) Involuntary action — Hindbrain (Medulla oblongata) - Differentiate between sensory neurons and motor neurons. ?
Sensory neurons carry impulses from receptors to brain While Motor neurons carry impulses from brain to effector. - Give the scientific names of the following regions of the human brain.
(i) Region for sight - Temporal lobe ( forebrain)
(ii) Region which controls salivationb -Medulla (hindbrain) - ‘Brain and spinal cord are two vital organs of our body’. How is our body designed to protect them?
The brain is located in a box of bones (skull). The fluid filled balloon inside the box contains the brain which protects from shocks. .
The spinal cord is protected by the vertebral column or spinal cord. - What is the significance of the peripheral nervous system?
The communication between the central nervous system and the other parts of the body is facilitated by the peripheral nervous system. Cranial nerves arise from the brain and spinal nerves arise from the spinal cord. - Define neuron.
Neuron is a functional and structural unit of nervous system. These cells are specialised for conducting information via electrical impulses from one part of the body to another. - What will be its effect on a person if there is :
(i) Deficiency of growth hormones?
Deficiency of growth hormone causes dwarfism.
(ii) Excess secretion of growth hormones? .
Excess secretion of growth hormone cause gigantism in a person. - What is reflex arc ?
The pathway through which stimuli reach the spinal cord from the affected organ and the signals generated from there reach back to the affected organ is called the "reflex arc".
A reflex arc is a neural pathway that controls a reflex action - What are plant hormones?
In plants, growth, development and response to the environment are controlled and coordinated by chemical substances which are known as phytohormones or plant hormones. - State how concentration of auxins stimulates the cells to grow longer on the side of shoot which is away from light?
Auxin is synthesized in the tip of the shoot but diffuses toward the part which is away from the light.The concentration of auxin on the side of the shoot away from light stimulates the cells to grow in length. - Why are adrenal glands known as glands of emergency ?
Adrenal glands release adrenaline hormone which enable the animal body to get ready to deal with the emergency.
When adrenaline is secreted into the blood, It prepares the body to face emergency situations by increasing heart beat, breathing rate and increasing the supply of oxygen to skeletal muscles - How does the Nervous Tissue Action?
The simplest notion of movement at the cellular level is that muscle cells will move by changing their shape so that they shorten. Muscle cells have special proteins that change both their shape and their arrangement in the cell in response to nervous electrical impulses. When this happens, new arrangements of these proteins give the muscle cells a shorter form. - Write two differences between the response of the plants and response of the animals to stimuli ?Plants Response1.No specific or specialized tissue present for conduction of information in plants2.Plant cells change shape by changing the amount of water in them.Animals Response1. Specialised tissues are present in the body for conduction of information in animals.2. Specialised proteins are found in muscle cells which help in changing the shape.
- Name the hormone synthesised at the shoot tips. How does it help the plant to respond to light?Auxin is synthesised at the shoot tips
When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. The concentration of auxin on the side of the shoot away from light stimulates the cells to grow in length. Hence the plant appears to be turning towards the light. - How do auxins promote the growth of a tendril around a support?
Auxin is a plant growth hormone which is synthesized at the tip of the shoot. It helps the cell grow longer.
Auxins are present at the tip of tendrils. When the tendril comes in contact with a support then auxin moves to away from the side of the support and stimulates faster growth of the cells on the opposite sides.Thus the tendril forms a coil around the support. - Name the hormones secreted by the following endocrine glands and specify one function of each:
(a) Thyroid : Thyroid secretes Throxine.
It regulates metabolism of carbohydrates, fats and proteins.
(b) Pituitary : Pituitary secretes growth harmone.
Growth harmone regulates growth and development of body.
(c) Pancreas : Pancreas Secretes insulin.
Insulin regulating the sugar level in the blood. - Give the function(s) of the following plant hormones: a. Auxins b. Gibberellins c. Cytokinins d. Abscisic acid e. Ethylene
1. Auxin:- It helps in increasing the length of cells.
2. Gibberellin:- It helps in the growth of the stem.
3. Cytokinin:- It stimulates cell division.
4. Abscisic acid:- It promotes falling of leaves and fruits
5. Ethylene : It promotes ripening of fruits. - The two glands A and B which occur in pairs are present in endocrine system. The pair of glands A is found only in females whereas the pair of glands B occur only in males. The gland A make and secrete hormone C whereas gland B make and secrete hormone E. In addition to hormone, gland A makes gamete F whereas gland B makes gamete G.
a. What are glands A and B?
Glands A - ovaries B-testes
b. Name the hormone C and E
Hormone C - oestrogen E-testosterone
c. Name the gamete F and G.
The gamete F - ova G-sperms - Draw the structure of a neuron and label the following on it:
Nucleus, Dendrite, Cell body and Axon - Name the parts (a) to (e) in the following diagram.
What is the term given to the sequence of events occurring in the diagram?
(a) Receptors (b) Sensory neuron (c) Spinal cord (CNS) (d) Relay neuron (e) Motor neuron - How do nerve impulses travel in the body? Explain.When a stimulus receives at the end of the dendritictip, an electrical impulse is produced with the help of chemical reaction.This impulse travels from the dendrite to the cell body, and then along the axon to its end.At the end of the axon, the electrical impulse releases of some chemicals. These chemicals cross the gap, or synapse and generate electrical impulse in a dendrite of the next neuron.
- How does adrenaline hormone help to deal with the scary situations?
This hormone increases the heartbeat resulting in supply of more oxygen to our muscles.
The breathing rate also increases due to contraction of the diaphragm and rib muscles.
The blood supply to the digestive system and skin is reduced due to contraction of arteries muscles
It directs blood towards our skeletal muscles.
All these responses together enable the animal body to deal with the scary situation. - List in tabular form two differences between the movement in ‘touch me not’ plant and movement of shoot towards light.
Movement of shoot towards light (Phototropism)
1.It is slow response towards any stimulus.
2. It is directional movement
3.It is dependent on growth .
Movement in “Touch me not’ plant (Nastic movement)
It is an immediate response towards a stimulus.
2..It is non-directional.
3. It is not dependent on growth . - How does feedback mechanism regulate the hormone secretion?The feedback mechanism is the mechanism through which the balance of hormone in the body is maintained. The increase or decrease in the concentration of hormone can either stimulate the secretion of that particular hormone or inhibit the hormone secretion.For example, The control of blood sugar by insulin is an example of a negative feedback mechanism. The increase in the blood sugar level stimulates the secretion of insulin This Insulin signals the cells to take up the blood glucose. Hence The glucose level decrease in the blood.Excessive secretion of insulin will scarcity of the glucose in the blood. Hence to prevent this, negative feedback is generated due to low glucose level which would inhibit the insulin secretion in the blood.
- Draw a labelled diagram of human brain. Describe the various parts of human brain
The brain has three major parts
1. Fore-brain -The fore-brain is the main thinking part of the brain. It has regions which receive sensory impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight.
Hypothalamus, a part of the fore brain which controls our hunger, thirst, hatred, love, etc.
2. Mid-brain- This part of the brain is located between the fore brain and hind brain. It is responsible for vision and hearing.
3. Hind-brain -It has two parts
(i) Cerebellum- Cerebellum controls voluntary actions like walking in a straight line, riding a bicycle, picking up a pencil etc. It is responsible for maintaining the posture and balance of the body.
(ii) Medulla oblongata - This is the last part of the brain which is connected to the spinal cord. All involuntary actions like heartbeat, blood pressure, salivation and vomiting are controlled by the medulla oblongata located in the hindbrain.
- Iodine is necessary for the synthesis of which of the following hormone?[A]Adrenaline[B]Auxin[C]Thyroxine[D]Insulin [C]
- Which endocrine gland is also known as ‘master gland’?[A]Pancreas[B]Adrenal[C]Pituitary[D]Hypothalamus [C]
- Which of the following is not a ductless gland?[A]Adrenal[B]Liver[C]Thyroid[D]Pituitary [B]
- A doctor advised a person to take injection of insulin because his:[A]Blood pressure was high[B]Heart beat was high[C]Blood sugar was high[D]Thyroxine level in blood was high [C]
- Which gland secretes the growth hormone?[A]Pituitary gland[B]Thyroid[C]Hypothalamus[D]Adrenal [A]
- Which of the following acts as both endocrine and exocrine gland?[A]Pancreas[B]Thyroid[C]Adrenal[D]Liver [A]
- Iodine is necessary for the synthesis of which hormone?[A] Adrenaline[B] Thyroxin[C] Auxin[D] Insulin [B]
- The hormone which increases the fertility in males is called[A] oestrogen[B] testosterone[C] insulin[D] growth hormone [B]
- Select the mismatched pair[A]Adrenaline – Pituitary gland[B]Testosterone – Testes[C]Estrogen – Ovary[D]Thyroxin – Thyroid gland. [A]
- Which of the following endocrine glands is unpaired?[A] Adrenal[B] Testes[C] Pituitary[D] Ovary [C]
- A growing seedling is kept in a dark room. A burning lamp is placed near to it for a few days. The top part of seedling bends towards the burning candle. This is an example of:[A]Chemotropism[B]Hydrotropism[C]Phototropism[D]Geotropism [C]
- The growth of pollen tubes towards ovules is due to[A] hydrotropism[B] chemotropism[C] geotropism[D] phototropism[B]
- Dandelion flowers open the petals in bright light during the daytime but close the petals in dark at night. This response of dandelion flowers to light is called:[A]Phototropism[B]Thigmonasty[C]Chemotropism[D]Photonasty [D]
- The stimulus in the process of thigmotropism is:[A]Touch[B]Gravity[C]Light[D]Chemical [A]
- The plant hormone which triggers the fall of mature leaves and fruits from the plant body is:[A]Auxin[B]Gibberellin[C]Abscisic acid[D]Cytokinin [C]
- Roots of plants are:[A]positively geotropic[B]negatively geotropic[C]positively phototropic[D]None of these [A]
- Which plant hormone promotes cell division?[A]Auxin[B]Gibberellin[C]Cytokinin[D]Abscisic acid [C]
- Which of the following is a plant hormone?[A]Insulin[B]Thyroxin[C]Oestrogen[D]Cytokinin [D]
- Which plant hormone promotes dormancy in seeds and buds?[A]Auxin[B]Gibberellin[C]Cytokinin[D]Abscisic acid [D]
- Response of plant roots towards water is called:[A]Chemotropism[B]Phototropism[C]Hydrotropism[D]Geotropism [C]
- Movement of sunflower in accordance with the path of Sun is due to[A]Chemotropism[B]Geotropism[C]Phototropism[D]Hydrotropism [C]
- Which of the following is not associated with growth of plant?[A] Auxin[B] Gibberellins[C] Cytokinins[D] Abscisic acid [D]
- The main function of the plant hormone called abscisic acid is to:[A]Increase the length of cells[B]Promote cell division[C]Inhibit growth[D]Promote growth of stem and roots [C]
- Which of the following tissues provide control and coordination in animals?[A]Nervous and Skeletal[B]Muscular and Skeletal[C]Muscular and Transport[D]Nervous and Muscular [D]
- How many pairs of cranial nerves are present in man?[A]12[B]21[C]31[D]41 [A]
- In a neuron, conversion of electrical signal to a chemical signal occurs at/in[A] cell body[B] axonal end[C] dendritic end[D] axon [B]
- Junctions of two neurons in called.[A]Synapse[B]Synapsis[C]Joint[D]Junction [A]
- The neurons that carry nerve impulse from spinal cord to effectors are called:[A]Sensory neurons[B]motor neurons[C]Inteneurons[D]spinal neurons [B]
- Which nerves transmit impulses from the central nervous system towards muscle cells?[A]Sensory nerves[B]Motor nerves[C]Relay nerves[D]Cranial nerves [B]
- A part of the body which responds to the in-structions sent from nervous system is called[A]receptor[B]effector[C]nerves[D]muscles [B]
- Which part of nervous system controls the reflex activities of the body?[A]Brain[B]Spinal cord[C]Cerebrum[D]Cerebellum [B]
- Spinal cord originates from[A] cerebrum[B] medulla[C] pons[D] cerebellum [B]
- Posture and balance of the body is controlled by[A]Pons[B]Medulla oblongata[C]Cerebellum[D]Cerebrum [C]
- The highest coordinating centre in the human body is[A]spinal cord[B]heart[C]brain[D]kidney [C]
- Which of the following controls the involuntary actions in the body?[A]Medulla in forebrain[B]Medulla in hindbrain[C]Medulla in spinal cord[D]Medulla in midbrain [B]
- The brain is lodged inside the cavity of skull known as :[A]Piamater[B]Duramater[C]Cranium[D]Meninges [C]
- Breathing is controlled by which part of the brain?[A]Cerebrum[B]Cerebellum[C]Hypothalamus[D]Medulla oblongata [D]
- Main function of cerebrum is[A]thinking[B]hearing[C]memory[D]balancing [A]
- Which of the following control and regulate the life process?[A]Reproductive and endocrine systems[B]Respiratory and nervous systems[C]Endocrine and digestive systems[D]Nervous and endocrine systems [D]
- Any change in the environment to which an organism responds is called[A]stimulus[B]coordination[C]response[D]hormone [A]
- Which of the following is not an involuntary action?[A] Vomiting[B] Salivation[C] Heart beat[D] Chewing [D]
- Dwarfism results due to :[A] Excess secretion of thyroxin[B] Less secretion of growth hormone[C] Less secretion of adrenaline[D] Excess secretion of growth hormone[B]
- Electrical impulse travels in a neuron from[A] Dendrite → axon axonal end → cell body[B] Cell body → dendrite → axon → axonal end[C] Dendrite → cell body → axon → axonal end[D] Axonal end → axon → cell body → dendrite [C]
- Which of the following statements is correct about receptors?[A] Gustatory receptors detect taste while olfactory receptors detect smell[B] Both gustatory and olfactory receptors detect smell[C] Auditory receptors detect smell and olfactory receptors detect taste[D] Olfactory receptors detect taste and gustatory receptors smell [A]
- Which of the following statements about transmission of nerve impulse is incorrect?[A] Nerve impulse travels from dendritic end towards axonal end[B] At the dendritic end electrical impulses bring about the release of some chemicals which generate an electrical impulse at theaxonal end of another neuron[C] The chemicals released from the axonal end of one neuron crossthe synapse and generate a similar electrical impulse in a dendrite of another neuron[D] A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells[B]
- Choose the incorrect statement about insulin[A] It is produced from pancreas[B] It regulates growth and development of the body[C] It regulates blood sugar level[D] Insufficient secretion of insulin will cause diabetes [B]
- When a person is suffering from severe cold, he or she cannot[A] differentiate the taste of an apple from that of an ice cream[B] differentiate the smell of a perfume from that of an agarbatti[C] differentiate red light from green light[D] differentiate a hot object from a cold object [B]
- Which of the following statements are true about the brain?(i) The main thinking part of brain is hind brain(ii) Centres of hearing, smell, memory, sight etc are located in fore brain.(iii) Involuntary actions like salivation, vomiting, blood pressureare controlled by the medulla in the hind brain(iv) Cerebellum does not control posture and balance of the body[A] (i) and (ii) [B] (i), (ii) and (iii)[C] (ii) and (iii) [D] (iii) and (iv)[C]
- Dramatic changes of body features associated with puberty are mainly because of secretion of[A] oestrogen from testes and testosterone from ovary.[B] estrogen from adrenal gland and testosterone from pituitary gland.[C] testosterone from testes and estrogen from ovary.[D] testosterone from thyroid gland and estrogen from pituitary gland. [C]
- Which of the following statements are true?
(i) Sudden action in response to something in the environment is
called reflex action
(ii) Sensory neurons carry signals from spinal cord to muscles
(iii) Motor neurons carry signals from receptors to spinal cord
(iv) The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc
[A] (i) and (ii)
[B] (i) and (iii)
[C] (i) and (iv)
[D] (i) , (ii) and (iii) [C] - What is the structural and functional unit of the nervous system?[A] Hormone[B] Neuron[C] Cell[D] Muscle [B]
- Walking in a straight line and riding a bicycle are the activities which are possible due to a part of the brain. Choose the correct location and name of this part from the given table :Part of the Brain Name[A] Fore brain Cerebrum[B] Mid brain Hypothalamus[C] Hind brain Cerebellum[D] Hind brain Medulla [C]
- In a synapse, chemical signal is transmitted from[A] dendritic end of one neuron to axonal end of another neuron[B] axon to cell body of the same neuron[C] cell body to axonal end of the same neuron[D] axonal end of one neuron to dendritic end of another neuron [D]
- The dramatic changes in body features associated with puberty are mainly because of the secretions of:[A]Estrogen from testes and testosterone from ovary[B]Estrogen from adrenal gland and testosterone from pituitary gland[C]Testosterone from testes and estrogen from ovary[D]Testosterone from thyroid gland and estrogen from pituitary gland [C]
- The growth of tendrils in pea plants is due to the:[A] Effect of sunlight on the tendril cells facing the sun[B]Effect of gravity on the part of tendril hanging down towards the earth[C]Rapid cell division and elongation in tendril cells that are away from the support[D]Rapid cell division and elongation in tendril cells in contact with the support [C]
- Identify which of the following statements about thyroxin is incorrect?[A]Thyroid gland requires iodine to synthesize thyroxin.[B]Thyroxin is also called thyroid hormone.[C]It regulates protein, carbohydrates and fat metabolism in the body.[D]Iron is essential for the synthesis of thyroxin. [D]
- Assertion: Plants do have a nervous system for control and coordination.Reason: Plants use electro chemical means to convey information from cell to cell.[A]Both A and R are true and R is the correct explanation of A.[B]Both A and R are true but R is not the correct explanation of A.[C]A is true but R is false.[D]A is false but R is true. [D]
- Assertion: Brain is a delicate organ which is protected from injury.Reason: The bony box protects the brain from any shock.[A]Both A and R are true and R is the correct explanation of A.[B]Both A and R are true but R is not the correct explanation of A.[C]A is true but R is false.[D]A is false but R is true. [C]
- Assertion: On attaining puberty, breast size increases and reproductive organs develop in females.Reason: Ovaries release hormone proges-terone in female.[A]Both A and R are true and R is the correct explanation of A.[B]Both A and R are true but R is not the correct explanation of A.[C]A is true but R is false.[D]A is false but R is true. [B]
- Assertion: Impulse travels from dendrite to cell body and then along the axon to its end.Reason: Information acquired at the end of the dendrite tip of a nerve cell sets of an electric impulse.[A]Both A and R are true and R is the correct explanation of A.[B]Both A and R are true but R is not the correct explanation of A.[C]A is true but R is false.[D]A is false but R is true. [A]
- Assertion: Reflex Arc works faster than thinking process of brain.Reason: Reflex Arc works in case of those animals who donot have thinking process.[A]Both A and R are true and R is the correct explanation of A.[B]Both A and R are true but R is not the correct explanation of A.[C]A is true but R is false.[D]A is false but R is true. [C]
