Control And Coordination - Class 10 MCQ

Gustatory Receptors
Gustatory receptors are specialized sensory cells located on the taste buds of the tongue and other parts of the oral cavity. Their main function is to detect and transmit signals related to taste to the brain. Here is a detailed explanation of the function of gustatory receptors:
Taste Detection
- Gustatory receptors are responsible for detecting different tastes, including sweet, salty, sour, bitter, and umami.
- These receptors are activated when chemical molecules from food or drink come into contact with the taste buds and bind to specific receptors on the gustatory cells.
- The binding of these molecules to the receptors triggers a series of electrical signals that are transmitted to the brain, where the perception of taste is formed.
Signal Transmission
- Gustatory receptors convert the chemical signals from food into electrical signals that can be transmitted to the brain.
- They accomplish this by generating action potentials, which are electrical impulses that travel along nerve fibers.
- These action potentials are then transmitted to the gustatory center in the brain, specifically the gustatory cortex, where the taste perception is processed and interpreted.
Taste Sensitivity
- Gustatory receptors vary in their sensitivity to different tastes.
- Some receptors are more sensitive to sweet tastes, while others are more sensitive to bitter or sour tastes.
- The distribution and density of these receptors on the tongue and oral cavity contribute to an individual's ability to perceive and differentiate tastes.
Adaptation
- Gustatory receptors can adapt to continuous exposure to the same taste stimulus.
- This adaptation allows the taste buds to remain sensitive to new tastes and prevent sensory overload.
- Over time, the receptors become less responsive to a particular taste, reducing the intensity of the taste perception.
In conclusion, the function of gustatory receptors is to detect and transmit signals related to taste. These receptors play a crucial role in our ability to perceive and differentiate various tastes, contributing to our overall sensory experience of food and drink.

Order of Events when a Bright Light is Focused on our Eyes:
The correct option that shows the order of events correctly when a bright light is focused on our eyes is Option A:

Order of Events:

• Bright light: The bright light enters our eyes.


• Receptors in eyes: The light is detected by the receptors in our eyes, specifically the photoreceptor cells called rods and cones.


• Sensory neuron: The receptors send signals to the sensory neurons, which transmit the information to the brain.


• Spinal cord: The sensory neurons pass the signals to the spinal cord, which acts as a relay station.


• Motor neurons: The spinal cord sends signals to the motor neurons.


• Eyelid closes: The motor neurons control the muscles responsible for closing the eyelid, causing it to close as a protective reflex against the bright light.

Therefore, the correct order of events is as follows: Bright light → Receptors in eyes → Sensory neuron → Spinal cord → Motor neurons → Eyelid closes.

Explanation:
The female in question is experiencing an irregular menstrual cycle, which is a clear indication of a hormonal imbalance. The doctor prescribed hormonal tablets to address this issue. In order to determine which hormone is lacking in her body and needs to be supplemented, we need to identify the hormone produced by an endocrine gland.
Endocrine glands are responsible for producing and releasing hormones directly into the bloodstream. The hormones produced by these glands regulate various physiological processes in the body, including the menstrual cycle.
The correct option is B: Oestrogen. Oestrogen is a hormone produced primarily by the ovaries in females. It plays a crucial role in regulating the menstrual cycle and maintaining reproductive health. When there is a deficiency of oestrogen in the body, it can lead to irregular periods or even a complete absence of periods.
Other options:
- Testosterone: Testosterone is a male sex hormone primarily produced in the testes. While females do have small amounts of testosterone, a deficiency in this hormone would not directly cause an irregular menstrual cycle.
- Adrenalin: Adrenalin, also known as epinephrine, is a hormone produced by the adrenal glands. It is involved in the body's response to stress and does not directly impact the menstrual cycle.
- Thyroxin: Thyroxin, also known as thyroid hormone, is produced by the thyroid gland. It regulates metabolism and energy levels in the body, but it does not directly affect the menstrual cycle.
Therefore, the hormone that the female lacks in her body is oestrogen, which is produced by the endocrine gland, the ovaries.

The plant uses electrical-chemical signals to transfer information from cell to cell.
The touch-me-not plant, also known as Mimosa pudica, has a unique response to touch. When its leaves are touched, they quickly fold up and droop. This response is a result of the plant's ability to communicate the information of touch through electrical-chemical signals transmitted from cell to cell. Here's a detailed explanation:
- Plant response to touch: When the touch-me-not plant's leaves are touched, it triggers a response known as thigmonasty. Thigmonasty is a rapid movement response of the plant to physical contact or mechanical stimulation.
- Electrical-chemical signaling: The touch-me-not plant has specialized cells called pulvinus at the base of each leaflet. These pulvinus cells play a crucial role in transmitting signals throughout the plant.
- Electrical signals: When the plant's leaves are touched, it initiates an electrical signal in the pulvinus cells. This electrical signal is generated by ion movement across the cell membranes, creating a change in electrical potential.
- Chemical signals: The electrical signal triggers the release of chemical messengers, such as calcium ions and hormones, within the pulvinus cells. These chemical messengers act as secondary messengers to propagate the signal further.
- Cell-to-cell communication: The chemical signals then travel from cell to cell, spreading the message of touch throughout the plant. This communication allows the plant to coordinate its response and ensure that all the leaves fold up and droop simultaneously.
- Response mechanism: The folding and drooping of the leaves occur due to changes in turgor pressure within the plant cells. The electrical-chemical signals cause a rapid loss of turgor pressure in the pulvinus cells, leading to the collapse of the leaflets.
In conclusion, the touch-me-not plant communicates the information of touch through electrical-chemical signals that travel from cell to cell. This intricate signaling system allows the plant to respond quickly and efficiently to physical stimuli.

Answer:
The brain and spinal cord are part of the central nervous system. Here is a detailed explanation of why they are considered part of the central nervous system:
Definition:
The central nervous system (CNS) is composed of the brain and spinal cord. It is responsible for processing and coordinating information received from the sensory organs and sending out commands to the rest of the body.
Brain:
- The brain is the command center of the body and controls all bodily functions.
- It receives sensory information from the sensory organs and processes it to create appropriate responses.
- It is responsible for cognition, emotions, memory, and consciousness.
- The brain is protected by the skull and is divided into various regions that perform specific functions.
Spinal Cord:
- The spinal cord is a long, thin bundle of nerves that extends from the base of the brain to the lower back.
- It acts as a pathway for communication between the brain and the rest of the body.
- It carries sensory information from the body to the brain and motor commands from the brain to the body.
- The spinal cord is protected by the spinal column, which is made up of vertebrae.
Role in the Central Nervous System:
- The brain and spinal cord work together to regulate and control all bodily functions.
- They receive and interpret sensory information, allowing us to perceive and understand the world around us.
- They generate appropriate motor responses, allowing us to move and interact with our environment.
- They play a crucial role in maintaining homeostasis, the body's ability to maintain a stable internal environment.
In conclusion, the brain and spinal cord are integral parts of the central nervous system. They are responsible for processing information, generating responses, and maintaining overall control of the body.

 

 

Parts of the Brain that Control Blood Pressure:
The brain plays a crucial role in regulating blood pressure. Specifically, the following parts of the brain are involved in controlling blood pressure:
1. Pons:
- Located in the brainstem, the pons is responsible for relaying signals between the cerebrum and the medulla.
- It contains the pontine respiratory group, which helps regulate breathing and plays a role in controlling blood pressure.
- The pons also contains the vasomotor center, which helps regulate blood vessel diameter and therefore influences blood pressure.
2. Medulla:
- The medulla oblongata, also located in the brainstem, contains the cardiovascular control center.
- This center regulates heart rate, blood vessel diameter, and blood pressure.
- Within the medulla, there are specific areas called the vasomotor center and the cardiac control center.
- The vasomotor center controls blood vessel constriction or dilation, affecting blood pressure.
- The cardiac control center regulates heart rate and force of contraction, which also impacts blood pressure.
3. Cerebellum:
- Although primarily associated with coordination and motor control, the cerebellum also has some influence on blood pressure regulation.
- It receives feedback from the cardiovascular system and helps adjust blood pressure as needed.
In conclusion, the pons, medulla, and cerebellum are the parts of the brain that control blood pressure. These regions work together to regulate heart rate, blood vessel diameter, and maintain blood pressure within the appropriate range.

Advantages of Hormones over Electric Impulses:
- Wide Distribution: Hormones are secreted by stimulated cells and reach all cells of the body. This allows for widespread communication and coordination within the organism.
- Targeted Action: Hormones can selectively target specific organs or tissues. This allows for precise regulation of physiological processes and avoids unnecessary stimulation of non-targeted areas.
- Long-Lasting Effects: Hormones can have prolonged effects compared to electric impulses. Once released into the bloodstream, hormones can continue to exert their effects for an extended period of time, allowing for sustained regulation of various bodily functions.
- Integration of Signals: Hormones can integrate signals from multiple sources and coordinate responses. They can be influenced by various factors such as environmental cues, internal conditions, and feedback loops, enabling complex regulation and adaptation.
- Independent of External Stimulus: Hormones can be generated in cells without the need for an external stimulus. This allows for autonomous regulation of hormonal secretion, which can be important for maintaining homeostasis and responding to changing conditions.
- Flexibility: Hormones can be released in response to specific physiological needs or stimuli. This flexibility allows for dynamic adjustments in hormone levels and responses based on the requirements of the organism.
In conclusion, hormones offer several advantages over electric impulses in terms of distribution, targeted action, long-lasting effects, signal integration, independence from external stimuli, and flexibility. These advantages contribute to the efficient and coordinated functioning of organisms.

Explanation:
The correct answer is D: Chewing.
Involuntary actions are those that occur without conscious control or intention. They are often controlled by the autonomic nervous system. Let's analyze each option to determine which one is not an involuntary action:
A: Vomiting
- Vomiting is an involuntary action controlled by the autonomic nervous system. It is the forceful expulsion of the contents of the stomach through the mouth.
B: Salivation
- Salivation is also an involuntary action controlled by the autonomic nervous system. It is the production and release of saliva in the mouth, stimulated by the presence of food or certain stimuli.
C: Heartbeat
- The heartbeat is an involuntary action controlled by the autonomic nervous system. It is the rhythmic contraction and relaxation of the heart, which pumps blood throughout the body.
D: Chewing
- Unlike the other options, chewing is a voluntary action. It is controlled by the somatic nervous system and can be consciously initiated or stopped.
In conclusion, chewing is the only option that is not an involuntary action.