2nd Year NotesBiology class 12th

2nd Year Biology Chapter 17 Coordination & Control

2nd Year Biology Chapter 17 Coordination & Control Question an Answer

Short and Simple Question and Answer

Q 1. What is coordination?

Ans. Coordination encompasses the organization, regulation, integration, and control in the structure and function of complex multicellular animals.

Q 2. Why does Chlorosis occur?

Ans. Chlorosis typically results from a lack of essential mineral nutrients in the soil.

Q 3. How is coordination achieved in higher animals?

Ans. Coordination in higher animals is achieved through nervous coordination and chemical coordination.

Q 4. What are photoreceptors?

Ans. Photoreceptors are sensory cells that respond to light stimuli, such as rods and cones in the eyes.

Q 5. What is Neuroglia?

Ans. Neuroglia refers to non-neuronal cells in the nervous system, making up a significant portion of it in higher animals, including humans.

Q 6. What are cranial nerves?

Ans. Cranial nerves are the 12 pairs of nerves that originate from or lead to the brain in humans.

Q 7. How does nicotine affect coordination?

Ans. Nicotine affects coordination by stimulating nerve impulses, increasing heart rate, blood pressure, digestive tract mobility, and potentially causing side effects like vomiting and diarrhea.

Q 8. What do ethologists think about animal responses?

Ans. Early ethologists believed that animals sometimes instinctively respond to specific and often complex stimuli referred to as “sign stimuli.”

Q 9. Define learning behavior?

Ans. Learning behavior is the process that leads to adaptive changes in individual behavior due to experience, as defined by Thorpe.

Q 10. Who studied operant conditioning or conditioned reflex type II?

Ans. Operant conditioning, also known as conditioned reflex type II, was studied by psychologists like Thorndike and B.F. Skinner.

Q 11. How can neuron fibers and cell bodies be stimulated?

Ans. Neuron fibers and cell bodies can be stimulated by small electric shocks, mechanical forces, chemicals, light, and changes in temperature.

Q 12. How do plants respond to stimuli?

Ans. Plants respond to stimuli by regulating their growth and development and controlling their body functions through the action of plant hormones.

Q 13. What are etiolated plants?

Ans. Etiolated plants are those that grow extremely long and fail to form sufficient chlorophyll when grown without light.

Q 14. What is Chlorosis?

Ans. Chlorosis is the condition in which many plants turn yellow due to insufficient chlorophyll production.

Q 15. What are calluses in plants?

Ans. Calluses in plants are undifferentiated masses of tissue that often form at wound sites.

Q 16. What are galls in plants?

Ans. Galls in plants are organized growths induced by parasites or bacteria, typically showing less differentiation compared to other plant tissues.

Q 17. Define biorhythms or biological rhythms?

Ans. Biorhythms, or biological rhythms, are regular intervals of behavioral activities that occur in living organisms.

Q 18. What are diurnal rhythms?

Ans. Diurnal rhythms, also known as circadian rhythms, are biorhythms with a periodicity of approximately 24 hours, reflecting daily patterns of activity.

Q 19. What is Circaannual?

Ans. Circaannual refers to biorhythms with a periodicity of less than or around 365 days.

Q 20. What are plant hormones?

Ans. Plant hormones are special substances produced by plants that influence their growth and responses to various stimuli.

Q 21. Name different plant hormones?

Ans. Plant hormones include auxins, gibberellins, cytokinins, abscisic acid, and ethylene.

Q 22. What are two functions of gibberellins?

Ans. Functions of gibberellins:

  1. Promote cell enlargement when auxins are present.
  2. Stimulate leaf and fruit growth.

Q 23. What is the use of GA3?

Ans. GA3 is used in the brewing industry to stimulate amylase production in barley, promoting malting.

Q 24. What are two functions of cytokinins?

Ans. Functions of cytokinins:

  1. Promote stem growth through cell division in apical meristems and cambium.
  2. Induce bud initiation.

Q 25. What is the commercial application of cytokinins?

Ans. Cytokinins are used to delay the aging of fresh leafy crops like cabbage and lettuce, keeping them fresh. They can also break seed dormancy.

Q 26. What are two functions of abscisic acid?

Ans. Functions of abscisic acid:

  1. Inhibits stem growth, particularly during physiological stress like drought or water-logging.
  2. Promotes bud dormancy.

Q 27. What is the commercial application of abscisic acid?

Ans. Abscisic acid can be sprayed on tree crops to regulate fruit drop at the end of the season, eliminating the need for picking over a long time.

Q 28. What is the commercial application of ethylene?

Ans. Ethylene induces flowering in pineapple, stimulates ripening in tomatoes and citrus fruit, and enhances latex flow in rubber plants.

Q 29. What is nervous coordination?

Ans. Nervous coordination involves specialized cells or neurons forming a network directly or through the central nervous system, connecting receptors (stimuli detectors) and effectors (response organs).

Q 30. What are the elements of the nervous system?

Ans. The elements of the nervous system include receptors, neurons, and effectors.

Q 31. What are Receptors?

Ans. Receptors detect changes in the external and internal environment and can be cells, neuron endings, or receptor organs.

Q 32. What are chemoreceptors?

Ans. Chemoreceptors are receptors stimulated by chemicals and include those for smell, taste, blood CO2 levels, oxygen, glucose, amino acids, and fatty acids.

Q 33. What are mechanoreceptors?

Ans. Mechanoreceptors detect touch, pressure, hearing, and equilibrium stimuli.

Q 34. What are thermo-receptors?

Ans. Thermo-receptors respond to cold and warmth.

Q 35. What are nociceptors?

Ans. Nociceptors are undifferentiated nerve endings that produce the sensation of pain.

Q 36. What is modality of sensation?

Ans. Modality of sensation refers to each type of primary sensory experience, such as pain, touch, sight, or sound.

Q 37. What are Meissner’s corpuscles?

Ans. Meissner’s corpuscles are encapsulated nerve endings located in papillae, particularly in the fingertips. They serve as touch receptors.

Q 38. What are Pacinian corpuscles?

Ans. Pacinian corpuscles are deep-lying, encapsulated nerve endings that respond to deep pressure stimuli and likely play a role in sensing vibration.

Q 39. What is Dendron or are dendrites?

Ans. Dendron is the cytoplasmic process carrying impulses toward the cell body, while dendrites are smaller fibers that perform the same function when present in multiple.

Q 40. What are Axons?

Ans. Axons are the processes that conduct impulses away from the cell body, and they can be quite long, exceeding a meter in some neurons.

Q 41. What are Nissl’s granules?

Ans. Nissl’s granules are clusters of ribosomes associated with rough endoplasmic reticulum, involved in protein synthesis, and present in the cell body of neurons.

Q 42. What is Cell body or soma?

Ans. The cell body or soma is the main nutritional part of a nerve cell, responsible for the biosynthesis of materials essential for neuron growth and maintenance.

Q 43. Name different types of neurons?

Ans. There are three functional types of neurons in mammals: sensory, associative (intermediate/relay), and motor neurons.

Q 44. What are Sensory Neurons?

Ans. Sensory neurons carry nerve impulses from receptors to the brain or spinal cord, characterized by a single, elongated dendron and a shorter axon.

Q 45. What are Motor Neurons?

Ans. Motor neurons transmit nerve impulses from the brain and spinal cord to effectors throughout the body, featuring a long axon and several small dendrites.

Q 46. What are Associative Neurons?

Ans. Associative neurons exclusively exist in the spinal cord and brain, serving as intermediate links between numerous sensory and motor neurons.

Q 47. What are Effectors?

Ans. Effectors are structures that respond when stimulated by impulses from motor neurons, including glands (for secretion) and muscles (for contraction).

Q 48. What is a reflex arc?

Ans. A reflex arc is the pathway of impulse transmission during a reflex action, typically an involuntary response. It involves receptors, sensory neurons, associative neurons, and motor neurons directing the stimulus from receptors to effectors.

Q 49. Define nerve impulse?

Ans. A nerve impulse is an electrochemical wave that travels along the length of a neuron, involving chemical reactions and the movement of ions across the cell membrane.

Q 50. Define electrical potential and membrane potential?

Ans. Electrical potential measures the capacity to perform electrical work. The electrical potential across a cell membrane is known as membrane potential.

Q 51. What is resting membrane potential?

Ans. Resting membrane potential is the electrical difference across a neuron’s cell membrane when it is at rest. Typically, the outside is more positively charged than the inside.

Q 52. What is active membrane potential?

Ans. Active membrane potential occurs briefly when a nerve impulse initiates, replacing the resting membrane potential. It represents the impulse in progress.

Q 53. What is salutatory impulse?

Ans. In myelinated neurons, the impulse jumps from node to node (node of Ranvier), known as salutatory impulse, which speeds up transmission.

Q 54. What is a synapse?

Ans. A synapse is a microscopic gap that exists between two neurons, where no direct cytoplasmic connection occurs. It’s the contact point for nerve impulse transmission.

Q 55. How does a nerve impulse pass from one neuron to another through the synapse?

Ans. A nerve impulse is transmitted from one neuron to another across the synapse using chemical messengers called neurotransmitters.

Q 56. What are neurotransmitters?Provide examples.

Ans. Neurotransmitters are chemicals released at the axon endings of neurons during synapses. Examples include acetylcholine, adrenaline, noradrenaline, serotonin, and dopamine.

Q 57. What is Acetylcholine?

Ans. Acetylcholine is the primary neurotransmitter involved in synapses outside the central nervous system.

Q 58. What are the different designs of nervous systems in the animal kingdom?

Ans. Nervous system designs in the animal kingdom include diffused nervous systems in Cnidarians (e.g., Hydra) and centralized nervous systems found in more complex organisms from Platyhelminthes to chordates, including humans.

Q 59. What are the main parts of the human nervous system?

Ans. The main parts of the human nervous system are the Central Nervous System and the Peripheral Nervous System.

Q 60. Name the two parts of the Central Nervous System?

Ans. The Central Nervous System consists of the Brain and the Spinal Cord.

Q 61. What is Cranium?

Ans. The cranium is the part of the skull that protects the brain and neural arches of the vertebrae.

Q 62. What are Meninges?

Ans. Meninges are the triple layers of protective membranes located beneath the cranium, surrounding the brain and spinal cord.

Q 63. What is Cerebrospinal fluid (CSF)?

Ans. Cerebrospinal fluid (CSF) is a fluid that bathes the neurons of the brain and spinal cord, providing cushioning and protection against physical shocks.

Q 64. Name different parts of the brain?

Ans. The brain can be divided into the forebrain, midbrain, and hindbrain.

Q 65. Name various parts of the forebrain?

Ans. The forebrain is divided into three functional parts:

  1. The thalamus
  2. The limbic system
  3. The cerebrum.

Q 66. What is the function of Thalamus?

Ans. The thalamus carries sensory information to the limbic system and cerebrum, including sensory input from auditory and visual pathways and from within the body.

Q 67. How does the limbic system work?

Ans. The limbic system works together to produce basic emotions, drives, and behaviors, including fear, rage, tranquility, hunger, thirst, pleasure, and sexual responses.

Q 68. What are the various parts of the limbic system?

Ans. The limbic system includes the hypothalamus, the amygdala, and the hippocampus, as well as nearby regions of the cerebrum.

Q 69. What is the role of the Hypothalamus?

Ans. The hypothalamus acts as a major coordinating center for controlling body temperature, hunger, the menstrual cycle, water balance, and the sleep-wake cycle.

Q 70. What is the role of the Amygdala?

Ans. The amygdala plays a role in producing sensations of pleasure, punishment, sexual arousal when stimulated, as well as feelings of fear and rage.

Q 71. What is the function of the Hippocampus?

Ans. The hippocampus is important in the formation of long-term memory and is required for learning.

Q 72. What are cerebral hemispheres?

Ans. Cerebral hemispheres are the two halves of the cerebrum. The left hemisphere controls the right side of the body, and the right hemisphere controls the left side.

Q 73. What is corpus callosum?

Ans. The corpus callosum is a large band of axons that connects the two cerebral hemispheres, enabling communication between them.

Q 74. What is the cerebral cortex?

Ans. The cerebral cortex is the outer region of the cerebrum with folds called convolutions, significantly increasing its surface area.

Q 75. What is reticular formation?

Ans. The midbrain contains the reticular formation, which acts as a relay center connecting the hindbrain with the forebrain. It screens and filters incoming sensory information before reaching higher brain centers.

Q 76. Name different parts of the hindbrain?

Ans. The hindbrain includes the medulla, pons, and cerebellum.

Q 77. What is the function of the Medulla?

Ans. The medulla controls automatic functions like breathing, heart rate, blood pressure, and swallowing.

Q 78. What is the role of the Pons?

Ans. Neurons in the pons influence transitions between sleep and wakefulness and regulate the rate and pattern of breathing.

Q 79. What is the role of the cerebellum?

Ans. The cerebellum coordinates body movements, guiding smooth and accurate motions and body position. It is also involved in the learning and memory storage of behaviors.

Q 80. What is the spinal cord?

Ans. The spinal cord is a hollow cylindrical structure that extends from the medulla oblongata through the vertebral column. It contains a large number of neurons arranged in a specific pattern.

Q 81. What is grey matter?

Ans. Grey matter in the spinal cord consists of cell bodies and non-myelinated nerve fibers or tracts. It forms a butterfly-shaped structure in cross-section.

Q 82. What is white matter?

Ans. White matter in the spinal cord is composed of myelinated nerve fibers or tracts and is located in the outer portion of the cord.

Q 83. What is the composition of the peripheral nervous system (PNS)?

Ans. The peripheral nervous system (PNS) is composed of sensory neurons, motor neurons, ganglia, and nerves.

Q 84. Are ganglia concentrations of cell bodies of neurons?

Ans. Yes, ganglia are concentrations of cell bodies of neurons.

Q 85. What are nerves?

Ans. Nerves are bundles of axons or dendrites bounded by connective tissue. They can be sensory, mixed, or motor nerves depending on the direction of impulse they conduct.

Q 86. What is chemical coordination?

Ans. Chemical coordination is a form of coordination in which the body uses chemicals, such as hormones, to regulate various physiological processes.

Q 87. What are spinal nerves?

Ans. Spinal nerves are the 31 pairs of nerves that arise from the spinal cord. These nerves are mixed, containing both sensory and motor neurons.

Q 88. What is the somatic nervous system?

Ans. The somatic nervous system is a part of the peripheral nervous system responsible for controlling voluntary movements, which are under conscious control, and involves skeletal muscles.

Q 89. Name the different parts of the autonomic nervous system?

Ans. The autonomic nervous system is divided into two parts: the sympathetic nervous system and the parasympathetic nervous system.

Q 90. What is the role of the sympathetic nervous system?

Ans. The sympathetic nervous system is responsible for the “fight or flight” response during emergency situations. It accelerates heart rate and inhibits digestive functions.

Q 91. What is the parasympathetic nervous system?

Ans. The parasympathetic nervous system promotes various internal responses such as contracting pupils, digestion of food, and slowing the heart rate.

Q 92. Name a few nervous disorders?

Ans. Nervous disorders include Parkinson’s disease, Addison’s disease, epilepsy, and Alzheimer’s disease.

Q 93. What is Parkinson’s disease (paralysis agitans)?

Ans. Parkinson’s disease is a nervous disorder characterized by symptoms like involuntary tremors, diminished motor power, and rigidity. It typically does not affect mental faculties and is associated with cell death in the brain area that produces dopamine.

Q 94. What is epilepsy?

Ans. Epilepsy is a neurological disorder characterized by abrupt, transient symptoms of motor, sensory, psychic, or autonomic nature, often associated with changes in consciousness. It typically has its onset before age 30.

Q 95. What is Alzheimer’s disease?

Ans. Alzheimer’s disease is a progressive brain disorder characterized by the decline in brain function, affecting memory, thinking, and behavior. It may have a genetic component and can be influenced by factors such as high aluminum levels.

Q 96. What are hormones?

Ans. Hormones are chemical compounds produced by endocrine or ductless glands. These glands are found throughout the body and release hormones directly into the bloodstream. Hormones regulate various physiological processes.

Q 97. Give two characteristics of hormones?

Ans. Characteristics of hormones:

  1. They are released directly into the bloodstream.
  2. They are transported by the blood to target tissues, where they elicit specific responses.

Q 98. What is the hypothalamus?

Ans. The hypothalamus is a part of the forebrain. It plays a crucial role in converting sensory stimuli into hormonal responses.

Q 99. What is the pituitary gland?

Ans. The pituitary gland, or hypophysis cerebri, is a small, oval-shaped gland connected to the brain via a short stalk (the infundibulum). It consists of three lobes: anterior, median, and posterior.

Q 100. Why is the pituitary gland called the “master gland”?

Ans. The anterior lobe of the pituitary gland is often referred to as the “master gland” because, in addition to producing primary hormones, it also releases trophic hormones that control the secretion of hormones in many other endocrine glands.

Q 101. Name the different hormones released by the anterior lobe of the pituitary gland?

Ans. The anterior lobe of the pituitary gland secretes the following hormones:

  • Somatotrophin
  • Thyroid-stimulating hormone (TSH)
  • Adrenocorticotropic hormone (ACTH)
  • Gonadotrophic hormones: i) Follicle-stimulating hormone (FSH) and ii) Luteinizing hormone (LH)
  • Prolactin

Q 102. Name the hormones released by the median lobe of the pituitary gland?

Ans. The median lobe of the pituitary gland secretes melanophore-stimulating hormone.

Q 103. Name the hormones released by the posterior lobe of the pituitary gland?

Ans. The posterior lobe of the pituitary gland releases two hormones:

  • Anti-diuretic hormone (ADH), also called vasopressin
  • Oxytocin

Q 104. Give one function of thyroxine and tri-iodothyronine.

Ans. Thyroxine and tri-iodothyronine increase the basal metabolic rate by stimulating the breakdown of glucose, releasing heat, and generating ATP.

Q 105. What is the effect of an over-secretion of thyroxine?

Ans. Excess thyroxine production leads to a condition called Graves’ disease. Symptoms include exophthalmic goiter and an increased basal metabolic rate. If prolonged, this can lead to cardiac failure.

Q 106. What is cretinism?

Ans. Cretinism is a condition that occurs in infants due to a deficiency of thyroxine. It results in a dwarfed appearance, coarse scanty hair, thick yellowish scaly skin, and mental retardation.

Q 107. What is myxedema?

Ans. Myxedema is a condition that occurs in adults due to a deficiency of thyroxine, often related to iodine shortage in the diet. Symptoms include neck swelling (goiter) and an increase in weight due to excess fat accumulation.

Q 108. What is calcitonin?

Ans. Calcitonin is a hormone produced by the thyroid gland in response to high calcium ion (Ca2+) concentration in the blood. It helps regulate calcium metabolism and its effects on the nervous system, skeleton, muscles, and blood.

Q 109. What is the action of glucagon?

Ans. Glucagon increases blood glucose levels by promoting the breakdown of glycogen to glucose in the liver and muscles. It also increases the rate of fat breakdown.

Q 110. Name the hormones released by the adrenal gland?

Ans. The adrenal gland produces two main types of hormones:

  • The adrenal medulla releases adrenaline and noradrenaline.
  • The adrenal cortex secretes aldosterone and androgenic hormones.

Q 111. What is the function of aldosterone?

Ans. Aldosterone is a mineralocorticoid hormone that conserves the level of sodium ions (Na+) in the body by preventing their loss from the kidney tubules.

Q 112. What is the function of cortisol?

Ans. Cortisol is a glucocorticoid hormone that increases blood glucose levels by promoting the breakdown of protein and antagonizing the action of insulin.

Q 113. What is the function of corticosterone?

Ans. Corticosterone is both a glucocorticoid and a mineralocorticoid hormone. It increases blood glucose levels and regulates mineral ion balance.

Q 114. What is Cushing’s disease?

Ans. Cushing’s disease occurs when there is an excessive production of cortical hormones. Symptoms include excessive protein breakdown, muscular and bone weakness, high blood sugar levels similar to diabetes, and other metabolic disturbances.

Q 115. What are androgens?

Ans. Androgens are male sex hormones responsible for developing secondary male characteristics. Small amounts of androgens are secreted in both male and female adrenal glands.

Q 116. What is gastrin?

Ans. Gastrin is a hormone produced by the mucosa of the pyloric region of the stomach. It stimulates the secretion of gastric juice and is produced in response to protein-rich food in the stomach.

Q 117. What is secretin?

Ans. Secretin is a hormone produced in the duodenum when acidic food touches its lining. It stimulates the pancreas to release pancreatic juice and affects the rate of bile production in the liver.

Q 118. Where are estrogen and progesterone produced?

Ans. Estrogens are secreted by ripening follicles in response to follicle-stimulating hormone (FSH) from the pituitary gland. Progesterone is produced by the ruptured follicle in response to luteinizing hormone (LH) from the pituitary.

Q 119. What are seminiferous tubules and interstitial cells?

Ans. Seminiferous tubules are coiled structures within the testes where spermatozoa develop. Interspersed between these tubules are interstitial cells, which produce gonadal hormones, such as testosterone.

Q 120. Define feedback mechanism?

Ans. A feedback mechanism is a form of interaction in which a controlling mechanism is influenced or regulated by the products of the reactions it is controlling.

Q 121. What is behavior?

Ans. Behavior refers to the actions and responses of an organism to stimuli. It encompasses all activities that animals engage in, such as flying, walking, eating, mating, and raising offspring.

Q 122. What is innate behavior?

Ans. Innate behavior comprises responses that are predetermined by specific nerve or cytoplasmic pathways in organisms. It is not learned and is typically present from birth. In plants, all behavior is considered innate.

Q 123. What are kineses?

Ans. Kineses are a type of behavior where an organism changes the speed of random movements, helping them adapt to their environment. For example, kineses may enable organisms to find a moist area necessary for their survival.

Q 124. What are taxes?

Ans. Taxes are directed movements in response to a stimulus, either towards (positive taxes) or away from (negative taxes) the stimulus.

Q 125. What are instincts?

Ans. Instincts, according to Darwin, are complex reflexes composed of units that are compatible with the mechanisms of inheritance. These reflexes have evolved together with other aspects of life through natural selection.

Q 126. Define learning?

Ans. Learning is a process that depends on an individual’s experiences throughout their life. It involves adaptive changes in behavior as a result of experience.

Q 127. What is the innate releasing mechanism (IRM)?

Ans. The innate releasing mechanism (IRM) is a built-in mechanism that recognizes sign stimuli, leading to selective responses to these stimuli.

Q 128. What is imprinting?

Ans. Imprinting is a form of learning in which an organism is briefly exposed to a stimulus, resulting in a long-lasting effect. It is well-known in birds like geese, ducks, and chickens.

Q 129. What is habituation?

Ans. Habituation is the simplest form of learning and involves modifying behavior through a reduction of response to repeated stimuli.

Q 130. Define conditioning or conditioned reflex type I?

Ans. Conditioning or conditioned reflex type I involves pairing an irrelevant stimulus with a natural primary stimulus that elicits an automatic response.

Q 131. Define operant conditioning or conditioned reflex type II?

Ans. Operant conditioning or conditioned reflex type II involves achieving a specific goal as a reward. It occurs through trial and error repetitions, eventually leading to the desired outcome.

Q 132. What is latent learning?

Ans. Latent learning involves the association of indifferent stimuli or situations without an immediately observable reward.

Q 133. What is insight learning?

Ans. Insight learning is an advanced form of behavioral modification in which insight or reasoning is applied to a novel situation.

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