Homeostaisis (2) Flashcards
(15 cards)
Define homeostasis
- Maintenance of ‘steady-state’
- integrative action of all systems within an organism to maintain an ‘optimal’ internal environment despite external challenges - maintain internal equilibrium adjusting physiological processes
Define set point and normal range.
Set point = the ideal normal value of a variable
Normal range = determine via set point as values fluctuate around
I.e.) body temp = 37.0°C + ranges from 36.5 - 37. 5°C
What is the role of organ systems in homeostasis t what are the 2 crucial systems?
- Help control the bodies internal environment
- key = communication btw systems
- nervous + endocrine systems = crucial be together they can gather sensory into from internal + external environments to send signals to the body systems signalling adjustments to be made
What are the 3 components of feedback systems?
Receptor = monitors the value of some variable
Control centre = establishes the set point
Effector = can change the value of the variable
Generally explain a feedback system
Explain the difference b/w positive/negative feedback loops.
Negative = returns the system to equilibrium le; increasing temperature
Positive = moves system further away from the target equilibrium ie., giving birth
Explain now we regulate temperature
- Negative feedback loop
- maintain temperature by balancing the loss of neat to the environment with the rate that is produced by the body
Explain positive feedback loops + now they are not typically normal
- When a deviation occurs, the response is to make the deviation greater
- unusual in healthy people, leads away from homeostasis + can result in death i.e., after hemorrhage -bp drops and the hearts ability to pump blood decreases
Explain a normal Positive feedback loop
Child birth
Is blood pressure during exercise non-homeostatic?
No - in some instances the set value or point is altered to a new normal determined by the environment they are in
- the hr increase indoses higher bp in order to maintain steady state. Increased demand in physical, metabolic, respiratory + CV effort
- the respiratory system maintains homeostasis by increasing breathing rate to match the consumption of oxygen to make ATP - we need more energy and this ATP
Give an example of a loss of homeostasis.
Twins- 1 is larger than the other - tomor on pituitary gland w increased released of growth hormone
Acromegaly = what, caused death
In a feedback system the ______ monitors changes in the variable or controlled condition
In a feedback system the RECEPTOR monitors changes in the variable or controlled condition
A body temperature of 37 degrees C is the _____ for body temperature?
A body temperature of 37 degrees C is the SET POINT for body temperature
The ___________ is the ideal normal value of a variable, determined by the __________ for that variable
The SET POINT is the ideal normal value of a variable, determined by the CONTROL CENTRE for that variable
Put the following steps of positive feedback in the correct Order:
- oxytocin released
- stretch receptors in cervix detect stretch
- uterus contract
- cycle continues until baby is born
- signal sent to the brain
- uterus contracts with greater force
- Uterus contract
- Stretch receptors in cervix detect stretch
- signal sent to the brain
- oxytocin released
- uterus contracts with greater force
- cycle continues until baby is born
