Question one
State the actions which takes place in human being in response to each of the following conditions;
When the surrounding temperature is low.
When the body temperature rises due to increase in surrounding temperature.
Answers:
Here are the actions that take place in the human body in response to the given conditions:
a. When the surrounding temperature is low:
When the surrounding temperature drops, the human body initiates several physiological responses to conserve heat and maintain its core temperature:
Vasoconstriction: Blood vessels near the surface of the skin constrict. This reduces blood flow to the extremities and the skin, minimizing heat loss through radiation and convection. The skin may appear pale as blood is diverted towards the warmer core of the body.
Shivering: Involuntary muscle contractions, known as shivering, generate heat. This rapid and repetitive muscle activity produces metabolic heat, which helps to raise the body's internal temperature.
Increased Metabolic Rate: The body's metabolism may increase slightly to produce more heat internally. This process can be triggered by hormonal changes.
Piloerection (Goosebumps): Small muscles at the base of hair follicles contract, causing the hairs to stand on end. While this is more effective in animals with thick fur to trap a layer of insulating air, in humans, it has a minimal effect on heat retention but is a physiological response to cold.
Behavioral Responses: Conscious actions like putting on warmer clothes, seeking shelter, huddling, and engaging in physical activity (which generates heat) are also crucial responses to a cold environment.
b. When the body temperature rises due to an increase in surrounding temperature:
When the surrounding temperature increases and threatens to raise the body's core temperature above its optimal level, the body activates mechanisms to dissipate heat:
Vasodilation: Blood vessels near the surface of the skin dilate, increasing blood flow to the extremities and the skin. This allows more heat from the core to be carried to the surface where it can be lost to the environment through radiation, convection, and conduction. The skin may appear flushed or red.
Sweating: Sweat glands are stimulated to produce sweat. As sweat evaporates from the surface of the skin, it absorbs heat from the body, providing a significant cooling effect.
Decreased Metabolic Rate: The body's metabolic rate may slightly decrease to reduce internal heat production.
Decreased Muscle Activity: The body tends to become less active to reduce the heat generated by muscle contractions.
Behavioral Responses: Conscious actions like removing layers of clothing, seeking shade, drinking cool fluids, and reducing physical activity are important ways to help the body cool down in a hot environment.
Question two
Explain any three (3) advantages of an organism being homoethermic
Answers:
Being homoethermic, also known as endothermic or warm-blooded, offers several significant advantages to an organism:
Independence from Environmental Temperatures: Homoethermic organisms can maintain a stable internal body temperature regardless of fluctuations in the surrounding environmental temperature. This physiological independence allows them to thrive in a wider range of habitats and climates, from freezing polar regions to scorching deserts. They are not limited by external temperature constraints that ectothermic (cold-blooded) animals face, which can restrict their activity levels and geographical distribution. This adaptability enhances their survival prospects in diverse and changing environments.
Sustained High Levels of Activity: Maintaining a constant and often high internal body temperature allows for optimal enzyme activity and metabolic rates. This enables homoethermic organisms to sustain high levels of physical activity for extended periods, whether it's for hunting prey, escaping predators, migrating long distances, or engaging in complex social behaviors. Unlike ectotherms whose activity levels are directly linked to external warmth, endotherms can remain active even when the environment is cold, giving them a significant advantage in terms of foraging, defense, and reproduction.
Enhanced Physiological Efficiency: The stable internal environment provided by homoethermy allows for more efficient physiological processes. Enzymes, which catalyze biochemical reactions within the body, function optimally within a narrow temperature range. By maintaining this optimal temperature, homoethermic organisms can ensure that their digestion, respiration, nervous system function, and other vital processes operate at peak efficiency. This leads to faster growth rates, quicker responses to stimuli, and overall improved physiological performance compared to organisms whose internal temperature fluctuates with the environment.
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