Control Of The Internal Environment:homeostasis,exercise And Adaption Flashcards
What is homeostasis
Maintenance of a constant ‘normal’ internal environment e.g. heart rate, body temp, arterial blood pressure
Changes in arterial blood pressure at rest:
Although arterial pressure oscillates over time, mean pressure remains constant due to baroreflex responses
Biological systems of the body:
Intracellular control systems:
1.protein breakdown and synthesis
2.energy production
3.maintenance of stored nutrients
Organ systems:
1.pulmonary and circulatory systems
2.replenish oxygen and remove carbon dioxide
What are the biological control systems
1.sensor or receptor-detects changes in variable
2.control centre-assesses input and initiates response
3.effector-changes internal environment back to normal
What is the negative feedback system
Response reverses the initial disturbance in homeostasis. Most control systems work via negative feedback
What is a positive feedback cycle
Biological response increases the original stimulus.
Example of homeostatic control:
Regulation of body temp. Thermal receptors send message to brain. Response by skin blood vessels and sweat glands regulates temperature
Concept of adaptation and acclimation
Adaption: change in structure and function of cell.
Results in improved ability to maintain homeostasis.
Acclimation:adaptation to environmental stresses e.g. heat or hypoxic stress
What is exercise induced hormesis
Process in which a low to moderate dose of potential harmful stress results in a beneficial adaptive response on the cell or organ system
What is cell signalling
1.communication between cells using chemical messengers
2.important for maintaining homeostasis
3.coordinates cellular activities
What are the 5 signalling pathways
1.intacrine signallinh
2.juxtacrine signalling
3.autocrine signalling
4.paracrine signalling
5.endocrine signalling
