Homeostasis GCSE Revision Quiz

During strenuous exercise, the body requires additional glucose to provide energy to the muscles. Glucose is the primary source of fuel for the body, and during intense physical activity, the muscles need more energy to perform effectively. The body breaks down glycogen stores in the liver and muscles to release glucose into the bloodstream, ensuring a steady supply of energy. This helps to sustain the physical activity and prevent fatigue. Therefore, the need for additional glucose arises during strenuous exercise to meet the increased energy demands of the body.

A synapse is the microscopic gap where two neurons meet and transmit impulses. It is the point of communication between neurons, where electrical signals are converted into chemical signals and transmitted across the gap. This allows for the transmission of information between neurons and is crucial for the functioning of the nervous system.

The correct answer is "Reflex arc." In the nervous system, a reflex action is controlled by a pathway called the reflex arc. This arc involves the sensory neurons, which receive stimuli from the environment, and transmit the information to the spinal cord. In the spinal cord, the information is quickly processed and a motor response is generated through motor neurons, which then carry the response to the muscles or glands involved in the reflex action. The reflex arc allows for rapid and automatic responses to certain stimuli without the need for conscious thought or decision-making.

Enzymes are proteins that catalyze biochemical reactions in the body. However, they are highly sensitive to changes in temperature. When the body temperature is too hot or cold, the enzymes undergo a process called denaturation. This means that the shape and structure of the enzyme is altered, leading to loss of its functional activity. Denatured enzymes are unable to bind to their substrates and carry out their catalytic function, rendering them ineffective. Therefore, in extreme temperatures, enzymes are denatured and do not work properly.

Vasodilation is the widening of blood vessels to allow more blood to flow to the surface of the skin and allow for the transfer of heat to the external environment.

A receptor is triggered by a stimuli, which refers to any kind of external or internal change or signal that can activate a receptor. The term "stimuli" is the plural form of "stimulus," indicating that multiple stimuli can trigger a receptor. This explanation is supported by the fact that receptors are specialized structures that detect and respond to specific stimuli, such as light, pressure, or chemicals, allowing organisms to perceive and react to their environment.

Reflex action is an involuntary reaction that does not require the involvement of the brain. It is a rapid and automatic response to a stimulus, which is mediated by the spinal cord or peripheral nerves. This type of action allows the body to respond quickly to potential threats or dangers without the need for conscious thought or decision-making from the brain.

The pituitary gland is located in the brain. It is a small, pea-sized gland that is situated at the base of the skull, just below the hypothalamus. The pituitary gland is often referred to as the "master gland" because it plays a crucial role in regulating various bodily functions by producing and releasing hormones. These hormones control growth, metabolism, reproduction, and many other important processes in the body. Therefore, it is clear that the correct answer is brain.

Homeostasis refers to the body's ability to maintain a stable and constant internal environment. This includes regulating various factors such as temperature, pH levels, blood sugar levels, and hormone levels. This process is essential for the proper functioning of cells, tissues, and organs. By maintaining a stable internal environment, homeostasis ensures that the body can carry out its normal physiological processes efficiently.

Type 1 diabetes is a condition in which the body's immune system destroys the cells in the pancreas that produce insulin. Insulin is a hormone that regulates blood sugar levels. Therefore, people with Type 1 diabetes cannot make the hormone insulin on their own. As a result, they need to take insulin injections or use an insulin pump to manage their blood sugar levels. Exercise and diet are important for managing diabetes, but they alone cannot compensate for the lack of insulin production in Type 1 diabetes.

The three types of neurons found in the nervous system are sensory neurons, relay neurons, and motor neurons. Sensory neurons are responsible for transmitting sensory information from the sensory organs to the central nervous system. Relay neurons, also known as interneurons, are located within the central nervous system and facilitate communication between sensory neurons and motor neurons. Motor neurons transmit signals from the central nervous system to the muscles and glands, allowing for movement and response.

The major organs of the nervous system are the brain and the spinal cord. The brain is the control center of the body, responsible for processing information, making decisions, and coordinating bodily functions. The spinal cord is a long bundle of nerves that runs down the back and connects the brain to the rest of the body. It serves as a pathway for transmitting signals between the brain and the body, allowing for communication and control of various bodily functions.

Enzymes are biological catalysts that speed up chemical reactions in the body. They are highly sensitive to temperature changes and have an optimal temperature at which they work most efficiently. The ideal temperature for enzymes to work in the body is 37 degrees Celsius. This is because the human body maintains a constant internal temperature of around 37 degrees Celsius, which allows enzymes to function optimally and maintain homeostasis. Deviations from this temperature can denature enzymes, leading to a loss of their catalytic activity.

This picture is most likely a synapse because it is a junction between two nerve cells where information is transmitted. The image may show the release of neurotransmitters from one neuron to another, allowing for the transmission of signals between the cells. This process is essential for communication within the nervous system.

Vasoconstriction refers to the narrowing of blood vessels, which reduces the flow of blood to the surface of the skin. This process is often triggered in response to cold temperatures or stress, as it helps to conserve heat and redirect blood to vital organs. Vasoconstriction can also occur as a result of certain medications or medical conditions. Conversely, vasodilation refers to the widening of blood vessels, which increases blood flow to the skin and other tissues.

A reflex action is an involuntary and rapid response to a stimulus, which involves the activation of neurons in the spinal cord or brainstem. This allows for a quick response to potential danger or harm. On the other hand, an action controlled by hormones is a slower process that involves the release of chemical messengers into the bloodstream. Hormones take time to travel through the bloodstream and reach their target cells, resulting in a slower response compared to reflex actions. Additionally, hormone-controlled actions may involve multiple organs and systems, while reflex actions mainly involve the nervous system.

The three components that make up all automatic control systems are effectors, receptors, and coordination centers. Effectors are responsible for carrying out the desired action or response, receptors detect and measure the current state or condition, and coordination centers receive information from receptors and send instructions to effectors to achieve the desired outcome. These components work together to create a closed-loop system that continuously monitors and adjusts the system's behavior based on feedback.

Hormones are chemical messengers that are carried around the body by blood. Blood acts as a transportation system, delivering hormones from the glands where they are produced to the target cells and organs where they exert their effects. This allows hormones to have a widespread influence on various bodily functions and maintain homeostasis. Nerves, oxygen, and glucose also play important roles in the body, but they are not specifically responsible for carrying hormones.

Excess glucose is converted into glycogen. Glycogen is a storage form of glucose that is stored in the liver and muscles. When blood glucose levels are high, the body converts the excess glucose into glycogen for later use. This process helps to regulate blood sugar levels and ensures that there is a steady supply of glucose available when needed.

The correct order for a reflex action is stimulus, receptor, sensory neuron, relay neuron, motor neuron, effector. This sequence begins with the stimulus, which triggers a response in the receptor. The receptor then sends signals through the sensory neuron to the relay neuron, which processes the information. The relay neuron then sends signals through the motor neuron to the effector, which carries out the response. This order ensures that the reflex action is carried out quickly and efficiently.

The pancreas secretes insulin when blood glucose levels rise. Insulin is a hormone that helps regulate blood sugar levels by allowing glucose to enter cells, where it is used for energy or stored for later use. When blood glucose levels rise, the pancreas detects this increase and releases insulin to help lower the glucose levels back to normal. This process is essential for maintaining stable blood sugar levels and preventing hyperglycemia.

Negative feedback is the main type of control that organisms use to maintain a stable internal environment. Negative feedback occurs when a change in a variable triggers a response that counteracts the initial change, bringing the variable back to its set point. This helps maintain homeostasis, the state of internal balance within an organism. In negative feedback, the response opposes the change, ensuring that the variable stays within a narrow range. This is different from positive feedback, where the response amplifies the initial change, and hormonal and nervous feedback are mechanisms that work within the negative feedback system.

Muscles and glands are effectors in the human body. Effectors are organs or structures that respond to signals from the nervous system or other stimuli. Muscles are effectors because they contract and relax to produce movement, while glands are effectors because they secrete hormones or other substances. Both muscles and glands play important roles in coordination and regulation of bodily functions.

The blue line represents the motor neuron in a reflex action. Motor neurons are responsible for carrying signals from the central nervous system to the muscles or glands, causing them to react or respond. In a reflex action, the motor neuron is activated by a sensory neuron, which detects a stimulus, and it then triggers a quick and automatic response without involving conscious thought. Therefore, the motor neuron is the correct answer as it is the neuron that carries the signal to initiate the reflex action.

The liver and pancreas are the two organs that help maintain glucose levels in the body. The liver plays a crucial role in regulating blood sugar levels by storing glucose as glycogen and releasing it when needed. It also helps in converting other substances into glucose through a process called gluconeogenesis. The pancreas produces insulin, a hormone that helps regulate blood sugar levels by facilitating the uptake of glucose into cells. Together, these two organs work to ensure that the body maintains a stable glucose level for proper functioning.

The purple line represents the sensory neuron in a reflex action. Sensory neurons are responsible for transmitting information from the sensory receptors to the central nervous system. In the context of a reflex action, the sensory neuron would detect a stimulus and send the information to the spinal cord or brain, triggering a rapid and involuntary response. This response is then carried out by the motor neuron, which controls the muscles or glands involved in the reflex action. Therefore, the sensory neuron plays a crucial role in initiating and transmitting sensory information in a reflex action.

The pancreas releases two hormones, glucagon and insulin. Glucagon helps to increase blood sugar levels by stimulating the liver to release stored glucose. On the other hand, insulin helps to lower blood sugar levels by allowing cells to take in glucose from the bloodstream. These two hormones work together to maintain the balance of blood sugar in the body.

A hormone reaction is different from a reflex action in two ways. Firstly, the response of a hormone reaction is slower compared to a reflex action. Hormones are chemical messengers that travel through the bloodstream to reach their target cells, which takes time. On the other hand, reflex actions are rapid and immediate. Secondly, a hormone reaction can affect many areas of the body as hormones are released into the bloodstream and can have widespread effects. In contrast, a reflex action typically affects only one specific part of the body, as it is a localized response to a specific stimulus.

The green molecules being released are neurotransmitter molecules. Neurotransmitters are chemical messengers that transmit signals between neurons in the brain and nervous system. They play a crucial role in communication between nerve cells and are released from the presynaptic neuron into the synaptic cleft, where they bind to receptors on the postsynaptic neuron, transmitting the signal. Therefore, the answer "neurotransmitter molecules" accurately describes the green molecules being released.

In this question, the correct order of the impulse flow from receptor to effector is given as "Stimulus, Receptor, co-ordinator, effector, response." This order follows the sequence of events in a reflex arc. The stimulus is the external factor that triggers a response. The receptor detects the stimulus and sends signals to the coordinator (usually the central nervous system) to process the information. The coordinator then sends signals to the effector, which is the muscle or gland that carries out the response. Finally, the effector produces a response.

A negative feedback is a regulatory mechanism in which a change in a physiological variable triggers a response that counteracts the initial change, bringing the variable back towards its set point or homeostasis. This helps maintain stability and balance in the body. Therefore, the correct answer is "stimulating a change towards homeostasis."

When the body needs to cool down, sweating occurs as a response to dissipate heat through the evaporation of sweat from the skin's surface. This helps to lower body temperature. Additionally, blood capillaries get wider, a process known as vasodilation. This allows more blood to flow near the skin's surface, facilitating heat loss through radiation and convection. Both sweating and vasodilation are mechanisms employed by the body to regulate and maintain its core temperature within a normal range.

The green line represents the relay neuron in a reflex action. Relay neurons, also known as interneurons, are responsible for transmitting signals between sensory neurons and motor neurons. They are found in the spinal cord and brain and play a crucial role in coordinating and integrating information during reflex actions.

A motor neuron carries signals from the central nervous system (CNS) to the effector. The effector is the muscle or gland that responds to the signal and produces a specific action. Motor neurons are responsible for transmitting these signals, allowing the CNS to control and coordinate voluntary and involuntary movements in the body.

The pancreas releases glucagon when blood glucose levels fall. Glucagon is a hormone that helps to increase blood glucose levels by stimulating the liver to convert stored glycogen into glucose and release it into the bloodstream. This hormone acts in opposition to insulin, which is released when blood glucose levels are high and helps to lower them by promoting the uptake and storage of glucose in cells.

Homeostasis refers to the body's ability to maintain a stable internal environment. The nervous system and endocrine system play crucial roles in achieving this balance. The nervous system controls and coordinates the body's activities through electrical signals and neurotransmitters, while the endocrine system regulates bodily functions through the release of hormones. These two systems work together to monitor and adjust various physiological processes, such as temperature, blood pressure, and metabolism, to ensure that the body remains in a state of equilibrium. Therefore, the interaction and coordination between the nervous system and endocrine system are essential for achieving homeostasis.

The neuron shown in the question is a motor neuron. Motor neurons are responsible for transmitting signals from the central nervous system to the muscles, allowing for voluntary movement. This type of neuron controls the contraction and relaxation of muscles, enabling us to perform various physical actions.

Excess glucose is stored in the liver and muscles. The liver acts as a storage site for glucose in the form of glycogen, which can be broken down and released into the bloodstream when needed. The muscles also store glucose as glycogen, but this glycogen is primarily used to provide energy for muscle contractions during exercise. Both the liver and muscles play important roles in regulating blood glucose levels and providing energy to the body.

The correct answer is pituitary gland. The pituitary gland is located at the base of the brain and is responsible for producing and storing various hormones, including antidiuretic hormone (ADH). ADH is released by the pituitary gland in response to signals from the brain and helps regulate the amount of water reabsorbed by the kidneys, thus controlling urine production.

The pancreas is both part of the control center, as it produces and secretes hormones such as insulin and glucagon to regulate blood sugar levels, and it also acts as a receptor and effector. As a receptor, it detects changes in blood sugar levels and releases the appropriate hormones to maintain balance. As an effector, it responds to the hormones it produces by releasing them into the bloodstream to regulate blood sugar levels.

The correct answer is "chemical neurotransmitter molecules". Neurons communicate with each other through small gaps called synapses. When an electrical signal reaches the end of a neuron, it triggers the release of chemical neurotransmitter molecules into the synapse. These molecules then bind to receptors on the next neuron, transmitting the signal across the synapse and allowing for communication between neurons.

The transmission of electrical impulses between neurons is primarily chemical. Neurons communicate with each other through the release and reception of chemical messengers called neurotransmitters. These neurotransmitters are released from the axon of one neuron and bind to receptors on the dendrites of another neuron, allowing the electrical signal to be transmitted. While there is an electrical component to the process, as the electrical impulse triggers the release of neurotransmitters, the overall transmission is considered to be chemical in nature.

Sensory neurons are responsible for carrying signals from the receptors (such as those in the skin, eyes, ears, etc.) to the central nervous system. These neurons transmit sensory information from the external environment or internal body conditions to the brain and spinal cord, allowing us to perceive and respond to various stimuli. They play a crucial role in our ability to sense and interpret the world around us.

Electrical impulses pass from one neuron to another through diffusion. Diffusion is the process by which particles move from an area of high concentration to an area of low concentration. In the context of neurons, when an electrical impulse, also known as an action potential, reaches the end of one neuron (the presynaptic neuron), it triggers the release of neurotransmitters into the synapse. These neurotransmitters then diffuse across the synapse and bind to receptors on the next neuron (the postsynaptic neuron), causing an electrical impulse to be generated in the postsynaptic neuron. This allows the signal to pass from one neuron to another.

The neuron shown in the image is most likely a sensory neuron. Sensory neurons are responsible for transmitting sensory information from the sensory organs to the central nervous system. They detect stimuli from the external environment or internal body and convert it into electrical signals that can be interpreted by the brain. Based on the limited information provided, it can be inferred that the neuron shown is involved in the transmission of sensory information rather than motor or processing functions.

A positive feedback is a process in which the initial stimulus or change is amplified, leading to a further deviation from the normal state of homeostasis. This means that the correct answer, "stimulating a change away from homeostasis," accurately describes the nature of positive feedback. In this type of feedback, the response reinforces and intensifies the original change, rather than working to restore balance or return to homeostasis.

When our body is trying to keep warm, it takes several actions to maintain a stable temperature. One of these actions is the reduction or cessation of sweating. Sweating helps to cool down the body, so when we are trying to keep warm, the production of sweat slows down or stops altogether. Another action is the contraction of muscles. Muscle contraction generates heat, which helps to warm up the body. Lastly, vasoconstriction occurs, which is the narrowing of blood vessels. This reduces blood flow to the skin's surface, minimizing heat loss and helping to retain warmth.

A relay neuron is a type of neuron that acts as a bridge between sensory and motor neurons, transmitting signals from one to the other. It receives information from sensory neurons and sends it to motor neurons, allowing for communication between different parts of the nervous system. The given answer "Relay neuron" suggests that the neuron shown in the question is responsible for relaying signals between sensory and motor neurons.

Breathing, coughing, and laughing are reflex actions because they are involuntary responses controlled by the autonomic nervous system. These actions occur automatically and do not require conscious effort or thought. Breathing is necessary for supplying oxygen to the body, coughing helps to clear the airways, and laughing is a natural response to humor or amusement. Childbirth, on the other hand, is not a reflex action as it involves a complex series of voluntary muscle contractions and conscious effort from the mother.