TAQ 1
Explain the term Homeostasis.
The term homeostasis is derived from two Greek words; homios meaning ‘the same’ and stasis meaning ‘steady’. It refers to the processes by which the body and internal cells seek to constantly maintain an internal state of balance and equilibrium even when faced with external environmental changes. This is achieved through either positive or negative feedback loop controls associated mainly with the endocrine and nervous systems. Principal homeostatic processes include regulation of blood pH, glucose, osmoregulation, and also temperature. Although some homeostatic mechanisms such as temperature control are unique to mammals and birds, all living organisms depend on effective internal regulation to some extent for survival.
Word Count- 106
TAQ 2
Part 1 – How is body temperature maintained including why this is necessary for the organism. (300 words)
In humans, maintenance of strict internal temperature homeostasis is crucial in providing the optimal temperature for which the bodies enzymes are able to act as catalysts for vital biochemical reactions within the cells. Even a few degrees fluctuation in core body temperature (outside of approximately 35-40°C) slows down the reactions to a point at which life is no longer sustainable. Whilst external environmental temperature is monitored via thermoreceptors in the skin, core body temperature is measured through and controlled via the extremely sensitive thermoregulatory centre of the hypothalamus. Fluctuations in core body temperature beyond the normothermic range (36-37.5°C) are recognised by neurons in the preoptic area of the hypothalamus, leading to a sensitive negative feedback loop mechanism governing whether to produce or lose heat (Tortora and Derrickson, 2013). When the body temperature changes, receptors within the skin and hypothalamus produce a response within the brain (the control centre) with produces the correct and appropriate effector response. (Cuddy, 2004). If the core temperature in the blood is recognised as being too low, the hypothalamus reacts by encouraging vasoconstriction, increasing metabolic rate (via secretion of adrenaline and thyroxine from the adrenal and thyroid glands), muscle contraction (shivering) and raised skin hairs. Raising skin hairs is however limited in effectiveness in humans. Conversely, when the core temperature is too high the body reacts through vasodilation, lowered metabolic rate, perspiration and lowering of skin hair (Kenney and Munce, 2003). Behavioural responses such as changing clothing or finding a cooler or warmer environment may then be initiated. Although these are generally very effective processes and mean that endotherms are able to predictably regulate their own temperature rather than being reliant on external sources, there are limitations in the mechanism, for example if exposed to extreme cold vasoconstriction may mean a person is effectively paralysed, preventing them escaping the situation. Endotherms are therefore far more vulnerable to large fluctuations in external temperatures than ectotherms, which can for example exist in a state of hibernation. Word Count – 320 Part 2 – Water is important for homeostasis, how are water levels maintained within the body and why is it important to do so? (400 words) Water is the principal component within the tissues and circulatory system, assisting with transport of oxygen and nutrients, and excretion of waste products. As such the homeostatic mechanisms governing the internal maintenance of water is crucially important for function. Fluid imbalance can cause a variety of complications such as oedema, heart failure and organ damage. At a cellular level it may lead to imbalances of electrolytes including sodium and potassium, which if uncorrected can be fatal. Osmoregulation therefore concerns the homeostatic mechanisms governing the balance of electrolytes and water within the body. Diffusion of either water or solutes to produce osmotic balance maintains the correct levels of electrolytes in cells, tissues and interstitial …show more content…
(400 words)
Blood glucose levels are regulated within a narrow range (typically 70mg/dl-110mg/dl) via the endocrine system. Whilst tight regulation is achieved mainly by insulin and glucagon hormones secreted by the pancreas, other hormones including somatostatin, epinephrine, cortisol, adrenocorticotrophic hormone and also T3 (triiodothyronine) and T4 (thyroxine) hormones from the thyroid gland also play a role.
Regular uncontrolled fluctation in blood glucose levels can have severe detrimental health effects, the most serious of which is the development of diabetes mellitus, which if left untreated can be
Explain the term Homeostasis.
The term homeostasis is derived from two Greek words; homios meaning ‘the same’ and stasis meaning ‘steady’. It refers to the processes by which the body and internal cells seek to constantly maintain an internal state of balance and equilibrium even when faced with external environmental changes. This is achieved through either positive or negative feedback loop controls associated mainly with the endocrine and nervous systems. Principal homeostatic processes include regulation of blood pH, glucose, osmoregulation, and also temperature. Although some homeostatic mechanisms such as temperature control are unique to mammals and birds, all living organisms depend on effective internal regulation to some extent for survival.
Word Count- 106
TAQ 2
Part 1 – How is body temperature maintained including why this is necessary for the organism. (300 words)
In humans, maintenance of strict internal temperature homeostasis is crucial in providing the optimal temperature for which the bodies enzymes are able to act as catalysts for vital biochemical reactions within the cells. Even a few degrees fluctuation in core body temperature (outside of approximately 35-40°C) slows down the reactions to a point at which life is no longer sustainable. Whilst external environmental temperature is monitored via thermoreceptors in the skin, core body temperature is measured through and controlled via the extremely sensitive thermoregulatory centre of the hypothalamus. Fluctuations in core body temperature beyond the normothermic range (36-37.5°C) are recognised by neurons in the preoptic area of the hypothalamus, leading to a sensitive negative feedback loop mechanism governing whether to produce or lose heat (Tortora and Derrickson, 2013). When the body temperature changes, receptors within the skin and hypothalamus produce a response within the brain (the control centre) with produces the correct and appropriate effector response. (Cuddy, 2004). If the core temperature in the blood is recognised as being too low, the hypothalamus reacts by encouraging vasoconstriction, increasing metabolic rate (via secretion of adrenaline and thyroxine from the adrenal and thyroid glands), muscle contraction (shivering) and raised skin hairs. Raising skin hairs is however limited in effectiveness in humans. Conversely, when the core temperature is too high the body reacts through vasodilation, lowered metabolic rate, perspiration and lowering of skin hair (Kenney and Munce, 2003). Behavioural responses such as changing clothing or finding a cooler or warmer environment may then be initiated. Although these are generally very effective processes and mean that endotherms are able to predictably regulate their own temperature rather than being reliant on external sources, there are limitations in the mechanism, for example if exposed to extreme cold vasoconstriction may mean a person is effectively paralysed, preventing them escaping the situation. Endotherms are therefore far more vulnerable to large fluctuations in external temperatures than ectotherms, which can for example exist in a state of hibernation. Word Count – 320 Part 2 – Water is important for homeostasis, how are water levels maintained within the body and why is it important to do so? (400 words) Water is the principal component within the tissues and circulatory system, assisting with transport of oxygen and nutrients, and excretion of waste products. As such the homeostatic mechanisms governing the internal maintenance of water is crucially important for function. Fluid imbalance can cause a variety of complications such as oedema, heart failure and organ damage. At a cellular level it may lead to imbalances of electrolytes including sodium and potassium, which if uncorrected can be fatal. Osmoregulation therefore concerns the homeostatic mechanisms governing the balance of electrolytes and water within the body. Diffusion of either water or solutes to produce osmotic balance maintains the correct levels of electrolytes in cells, tissues and interstitial …show more content…
(400 words)
Blood glucose levels are regulated within a narrow range (typically 70mg/dl-110mg/dl) via the endocrine system. Whilst tight regulation is achieved mainly by insulin and glucagon hormones secreted by the pancreas, other hormones including somatostatin, epinephrine, cortisol, adrenocorticotrophic hormone and also T3 (triiodothyronine) and T4 (thyroxine) hormones from the thyroid gland also play a role.
Regular uncontrolled fluctation in blood glucose levels can have severe detrimental health effects, the most serious of which is the development of diabetes mellitus, which if left untreated can be