NTSE Level Test: Control & Coordination - UPSC MCQ

Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves (which emerge from segments of the spinal cord). 10 of 12 of the cranial nerves originate in the brainstem. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck.

• Muscles: Muscles play a role in reflex actions by contracting or relaxing in response to a stimulus.



• Limbs: Limbs are involved in carrying out the reflex action, such as moving away from a painful stimulus.



• The Spinal Chord: The spinal cord plays a crucial role in controlling reflex actions. When a stimulus is detected, sensory neurons in the skin or other sensory organs send signals to the spinal cord. The spinal cord then processes this information and sends signals back through motor neurons to carry out the appropriate response, all without involving the brain. This quick response is essential for survival in potentially dangerous situations.



• Autonomic Nervous System: The autonomic nervous system controls involuntary actions, such as heartbeat and digestion, but not reflex actions. Reflex actions are typically controlled by the spinal cord to allow for quick responses without the need for conscious thought.

When a receptor is stimulated, it sends a signal to the central nervous system, where the brain coordinates the response. But sometimes a very quick response is needed, one that does not need the involvement of the brain. This is called as the reflex action. In a simple reflex action:
Stimulus -> Receptor -> Sensory neuron -> Relay Neuron -> Motor neuron -> Effector (Muscle).
So, the correct answer is 'Receptors - Sensory neuron - Spinal cord - Motor neuron - Muscle'

• Medulla Oblongata: The medulla oblongata is responsible for controlling many involuntary functions of the body, including breathing, heart rate, and blood pressure. It is located at the base of the brainstem and plays a crucial role in maintaining homeostasis.


• Cerebrum: The cerebrum is primarily responsible for voluntary actions, such as movement and decision-making. It is not directly involved in controlling involuntary actions.


• Cerebellum: The cerebellum plays a role in coordinating movement and balance, but it is not the primary control center for involuntary actions.


• Diencephalon: The diencephalon includes structures like the thalamus and hypothalamus, which are involved in regulating processes like sleep, temperature, and hormone production. While important for overall function, the diencephalon is not the main controller of involuntary actions.

• Unbalanced Movement: Damage to the cerebellum can result in uncoordinated movements, making it difficult for the individual to maintain balance and control their body movements.



• Uncontrolled Walking: The individual may experience difficulty in walking, with movements appearing uncontrolled and unstable.



• Defective Speech: Damage to the cerebellum can also affect speech, causing slurred or uncoordinated speech patterns.



• Intention Tremor: Individuals with cerebellar damage may exhibit intention tremor, which is a tremor that occurs during purposeful movements, such as reaching for an object.

Hormone, secretin: Hormone made by glands in the small intestine that stimulates pancreatic secretion. The word "hormone" was coined by the English physiologists Wm. M. Bayliss and Ernest H. Starling in connection with their discovery of secretin, the first hormone, in 1902.

Progesterone is an anti abortion hormone. 
It is mainly secreted by the corpus luteum in the ovary during the second half of the menstrual cycle. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. Hence, progesterone is called as the " Anti-national abortion hormone ".

Cretinism is a condition of severely stunted physical and mental growth owing to untreated congenital deficiency of thyroid hormone (congenital hypothyroidism) usually owing to maternal hypothyroidism.

• Olfactory Receptors: These are sensory neurons located in the olfactory epithelium in the nasal cavity that are responsible for detecting odors.


• Sense of Smell: Olfactory receptors are directly related to the sense of smell. They detect chemical molecules in the air that we perceive as different odors.


• Function: When odor molecules bind to olfactory receptors, they trigger a signal that is sent to the brain, where it is processed and interpreted as a specific smell.


• Differentiation: Olfactory receptors are distinct from receptors for other senses such as sight, touch, and hearing, as they specifically respond to chemicals in the environment.


• Importance: The sense of smell plays a crucial role in our daily lives, influencing our food preferences, evoking memories, and even alerting us to dangers like spoiled food or gas leaks.

The basal metabolic rate, which is the amount of calories required by the body at rest, is determined by two hormones produced by the thyroid gland :- thyroxine. 

A hormone called parathyroid hormone regulates the levels of calcium and phosphorus in your blood. When the phosphorus level is measured, a vitamin D level, and sometimes a PTH level, is measured at the same time. Vitamin D is needed for your body to take in phosphate.

• Adrenaline: Adrenaline, also known as epinephrine, is the fight, flight, and fright hormone.


• Glucagon: Glucagon is a hormone that works to raise blood sugar levels.


• Insulin: Insulin is a hormone that works to lower blood sugar levels.


• Oxytocin: Oxytocin is often referred to as the "love hormone" as it plays a role in social bonding and maternal behavior.

• Adrenaline is produced by the adrenal glands in response to stress or danger.


• It triggers the body's fight or flight response, preparing the body to react quickly in dangerous situations.


• Adrenaline increases heart rate, dilates airways, and redirects blood flow to the muscles, providing a burst of energy.


• It can also cause sweating, trembling, and heightened senses, all of which help in dealing with threatening situations.

• Adrenaline is the hormone responsible for the fight, flight, and fright response in the body.


• It is crucial for survival in dangerous situations and helps the body to react quickly and effectively to threats.

• Testosterone: Testosterone is the primary male sex hormone responsible for the development of secondary sexual characteristics in males. It is produced in the testes and is responsible for the deepening of the voice, growth of facial and body hair, increased muscle mass, and bone density in males.


• Progesterone: Progesterone is a female sex hormone that plays a role in the menstrual cycle and pregnancy. It is not responsible for the development of secondary sexual characteristics in males.


• Thyroxine: Thyroxine is a hormone produced by the thyroid gland that regulates metabolism. It does not control the appearance of secondary sexual characteristics in males.


• Estrogen: Estrogen is the primary female sex hormone responsible for the development of secondary sexual characteristics in females. It is not responsible for the development of secondary sexual characteristics in males.

The liver and pancreas are both exocrine and endocrine glands; they are exocrine glands because they secrete products—bile and pancreatic juice—into the gastrointestinal tract through a series of ducts, and endocrine because they secrete other substances directly into the bloodstream.

• Growth Hormone: Growth hormone is responsible for stimulating growth, cell reproduction, and regeneration in humans. It plays a crucial role in the growth and development of bones and tissues.


• Hyposecretion: When there is a deficiency or underproduction of growth hormone in children, it can lead to a condition known as dwarfism. Dwarfism is characterized by significantly shorter stature than average for a person's age and gender.


• Effects of Hyposecretion: Children with growth hormone deficiency may experience delayed growth and development, resulting in short stature and proportionate body size.


• Treatment: Treatment for growth hormone deficiency typically involves hormone replacement therapy to stimulate growth and development in affected children.

The correct answer is B as shrinkage of thymus mainly takes place due to a high level of sex hormones.

The correct option is C.
Hyposecretion of the glucocorticoid hormone cortisol leads to a disorder called Addison's disease. There may also be hyposecretion of mineralocorticoids with this disorder.

• Hypothalamus: The secretion of pituitary hormones is primarily regulated by the hypothalamus. The hypothalamus produces releasing hormones that stimulate or inhibit the release of hormones from the pituitary gland.



• Thyroid: While the thyroid gland plays a role in the endocrine system and secretes hormones that regulate metabolism, it does not directly regulate the secretion of pituitary hormones.



• Thymus: The thymus gland is primarily involved in the immune system and the development of T-cells, and does not have a direct role in regulating pituitary hormone secretion.



• Adrenal: The adrenal glands produce hormones such as cortisol and adrenaline, but they do not directly regulate the secretion of pituitary hormones.

Therefore, the correct answer is the Hypothalamus, which plays a crucial role in regulating the secretion of pituitary hormones through the production of releasing hormones.

• Thyroxine: Thyroxine is the hormone responsible for metamorphosis in frogs.


• Role in metamorphosis: Thyroxine plays a crucial role in regulating the metamorphosis process in frogs.


• Transformation: It triggers the transformation of tadpoles into adult frogs by controlling the development of various body parts such as limbs, tail, and internal organs.


• Timing: Thyroxine levels increase significantly during the metamorphosis stage, indicating its importance in this process.


• Regulation: The production and release of thyroxine are regulated by the pituitary gland in response to environmental cues such as temperature and light.

In frogs, growth and metamorphosis is regulated by Thyroxine gland. Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues. Hence, tadpoles will undergo metamorphosis if they are injected with thyroxine.

Hypercalcemia is a condition in which the calcium level in your blood is above normal. Too much calcium in your blood can weaken your bones, create kidney stones, and interfere with how your heart and brain work. Hypercalcemia is usually a result of overactive parathyroid glands.

Cortisol is  steroid hormone that is produced by the adrenal glands, which sit on top of each kidney.

• Meant for detecting pressure in the skin


• For magnifying sound in the internal ear


• Internal sense organs which occur most frequently in muscles


• For the detection of direction of waves in fishes

• Proprioceptors are specialized sensory receptors that are located in muscles, tendons, and joints.


• They provide information to the brain about body position, movement, and balance.


• Proprioceptors are crucial for coordination and control of movement.


• These receptors are responsible for detecting changes in muscle length and tension, as well as joint position.


• Proprioceptors help the body maintain proper posture and execute smooth, coordinated movements.


• They are not meant for detecting pressure in the skin or magnifying sound in the internal ear.


• While some animals may use specialized receptors for the detection of waves in water, this is not the primary function of proprioceptors.

• Synapse: The gap between two neurons where nerve impulses are transmitted chemically


• Synopsis: A brief summary or general survey of something


• Impulse: A sudden strong and unreflective urge or desire to act


• Synaptic node: A structure within a synapse that allows for the transmission of signals between neurons

In this case, the correct answer is A: synapse. The synapse is a crucial structure in the nervous system that allows for communication between neurons. When an electrical signal reaches the end of one neuron, it triggers the release of neurotransmitters into the synapse, which then bind to receptors on the next neuron, thus transmitting the signal. Understanding the role of the synapse is essential in studying how information is processed in the brain and how neurological disorders may arise due to disruptions in synaptic function.