Homeostasis Flashcards
Homeostasis – a reasonable definition
• Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes
Homeostasis
• In order to function properly and efficiently, organisms have different control systems that ensure their internal conditions are kept relatively constant
• The process of maintaining constant internal body conditions is known as homeostasis
• Homeostasis is critically important for organisms as it ensures the maintenance of optimal conditions for enzyme action and cell function
• Sensory cells detect information about the conditions inside and outside of the body and start the process of making changes needed
The control mechanisms
• These are the core component that all the body systems use to maintain the internal environment around the optimum point using negative feedback.
Negative feedback
A negative feedback mechanism is an important type of control that is found in homeostasis. It responds when conditions change from the ideal or set point and returns conditions to this set point. There is a continuous cycle of events in negative feedback.
General stages in negative feedback
In general this works in the following way:
• if the level of something rises, control systems reduce it again
• if the level of something falls, control systems raise it again
optimum point
• The optimum point is the point at which the system operates best. This is monitored by a receptor that detects any deviation from the optimum point and informs the coordinator which coordinates information from receptors and send instructions to an appropriate effector, often a muscle or gland which brings about the changes needed to return the system to the optimum point. This return to normality creates a feedback mechanism by which a receptor responds to a stimulus created by the change to the system brought about by an effector
Nervous and Endocrine system
• One or both systems may be used to effect and change and return to the optimum points so each example may use examples from one or both in the control mechanisms.
• Thermoregulation is effected mainly by the nerves of the muscular skeletal system and the integumentary system but also hormones (T3 and T4) that increase metabolic rate so more internal heat (or less) is generated.
• These systems need to work together so sweating and vasoconstriction simultaneously would be ineffective in reducing body temperature for example
Impact of failure of the control mechanisms
• Homeostasis maintains stability and function of the physiological systems and cells when there are changes to internal and external conditions that would otherwise prevent enzymes from functioning
normally.
• When one of the components of a control mechanisms fails cells work incorrectly resulting in possible toxicity or deficiency to the body
• An excess or deficiency can also cause diseases –hyperpyrexia, diabetes and oedema
Impact generally of failure of homeostatis
When there is a failure to maintain the body’s internal environment then disorders can develop:
• failing to regulate body temperate can lead to hypothermia and heat stroke and how failing to regulate blood sugar can lead to hypoglycaemia and hyperglycaemia for example in diabetes
What factors influence changes in physiological measurements?
(Infection)
• Infections will initiate an immune response & therefore cause changes in physiological measurements.
• E.g. an increase in body temperature (fever) is a common physiological response to an infection, as the body tries to fight off the invading pathogens
What factors influence changes in physiological measurements?
(Chronic illness / Disease)
• Various diseases can result in alterations in physiological measurements.
• Chronic illnesses, such as diabetes or kidney disease, can have a long-term impact on physiological measurements. These conditions can cause fluctuations in blood glucose levels, electrolyte imbalances, and changes in vital signs.
• E.g. conditions like hypertension can cause elevated blood pressure readings, while heart diseases may lead to abnormal heart rate patterns
What factors influence changes in physiological measurements?
(Age/Weight)
• Age and weight can influence physiological measurements significantly.
• For example, as individuals age, their heart rate may decrease, and blood pressure may increase.
• Additionally, obesity can lead to changes in blood pressure, cholesterol levels, and insulin resistance
What factors influence changes in physiological measurements?
(Hydration and Nutritional Status)
• Adequate hydration and proper nutrition are crucial factors that influence physiological measurements.
• Dehydration can lead to low blood pressure, increased heart rate, and electrolyte imbalances.
• On the other hand, poor nutrition can result in deficiencies that affect various physiological processes, such as insufficient iron levels leading to anemia
What factors influence changes in physiological measurements?
(Environment)
• The environment can have a significant impact on physiological measurements.
• Extreme temperatures, such as hypothermia or hyperthermia, can cause changes in body temperature
What factors influence changes in physiological measurements?
(Lifestyle)
• Lifestyle choices, including smoking, drug use, diet, and stress, can affect physiological measurements.
• Smoking, for instance, can lead to increased heart rate and blood pressure. Substance abuse can cause irregularities in heart rate, blood pressure, and other vital signs.
• Unhealthy diets and chronic stress can also have adverse effects on physiological measurements
What factors influence changes in physiological measurements?
(Medication)
• Certain medications can induce changes in physiological measurements.
• For example, beta blockers can lower heart rate and blood pressure, while statins can affect cholesterol levels. Inhalers can impact lung function, and paracetamol can reduce fever
