Homeostasis 1 Flashcards
What is homeostasis?
The tendency towards a reletively stable equilbrium between interdependent elements
What are our bodies composed of and how are they organised?
Cells—Tissues—Organs—Systems—Organism
What is a tissue?
Groups of cells that show the same characteristics or specialisations
What is an organ?
Collection of tissues, usually of several different types, that collaborate to perform a specific function
What is the basic equation of life?
Nutrients + O2 → Energy (ATP) + CO2 + waste
All living cells require energy to survive
In terms of homeostasis, what happens once energy demand increases?
The supply of substrates required to produce that energy must also increase to maintain homeostasis and prevent a disturbence to the system
Why is maintaining constancy of the internal environment important?
All fundamental physiological processes require a constrant internal environment
How does homeostasis require the integation of organ systems?
Sensory and musculoskeletal supply nutrients
Respiration supplies 02
Alimentary breaks down food
Cardiovascular carries O2 and nutrients to cells and removes waste
Renal systems disposes of waste
What systems coordinate the integration of organs?
Nervous and endocrine
At what levels is regulation required to maintain homeostasis?
Cell
Tissue
System
What is physiology?
Our bodies constantly monitoring their internal state and responding to any disruptions in order to maintain homeostasis
What does failure to maintain homeostasis result in?
Illness, disease or pathology
Our bodies are not very tolerable of substantial changes in our internal environment such as?
Temperature
pH
Concentration of hormones
Does our body have a range around optimum level that it can tolerate?
Yes
How is a constant level maintained?
Input must match the output
What are common everyday challneges to homeostasis?
External temperature
Diet
Exercise
What does a chart that shows homeostasis regulation look like?
At extremes homeostasis becomes less effective
What type of control system regulates tissue and organ systems?
Negative feedback control systems
What is the process of a negative feedback control system?
- Change is sensed by receptor
- Feeds information to integration centre and compares to reference level
- Any difference generates a signal that is fed to an effector molecule
- Response is produces that corrects original change
Is the size of the generated signal proportionate to the size of the difference from normal in a negative feedback control system?
Yes
What is the aim of a negative feedback control system?
Return the internal environment to optimal conditions
What are characteristics of a negative feedback system?
Oscillate around a set point
Restores regulated variable after its initial displacement, cannot prevent it from happening
What is a feed forward system?
A more sphisticated form of negative feedback that can prevent change from happening in the first place
What are characteristics of a feed forward system?
Additional receptors allow system to anticipate change and activate a response sooner
To an extent can predict and prevent change
What is positive feedback?
Leads to even greater disturbance
What is negative feedback?
Aims to restore conditions to optimum
Positive feedback is rare in physiology, but where does it occur?
Nerve action potential
Ovulation and sexual behaviour
What is the aim of medicine?
To restore homeostasis control when it is disturbed by illness or disease
