Introduction to physiology. Flashcards
What is homeostasis?
the ability to maintain relitively stable conditions in the internal environment (despite changes in the external environment)
How does Homeostasis help cells survive?
Because the cells can only survive under a narrow range of conditions… it allows the cells to live.
What kind of conditions are controlled by Homeostasis?
1) pH
2) Tempature
3) blood gasses (CO2/ O2)
4) Blood pressure (b.p.)
5) Intracellular + Extracellular (ICF + ECF) fluid
6) Etc.
By which systems are change in internal environments detected or anticipated?
the nervous system and/or the endocrine system
what are the different types of endocrine reponses?
Anticipatory responses and Feedback Mechanisms
What is an anticipatory Response?
can be where respiratory rate at start of exercise rises (where proprioceptors signal movement before change in internal conditions occurs (gases in blood)
can also be learned or behaviour like putting a coat on when its cold outside
what are Feedback Mechanisms?
They are mechanisms that respond to a change in the system.
What do Feedback Mechanisms consist of?
set points, receptors, control areas and effectors
out of Anticipatory Responses and Feedback Mechanisms, which are most common?
Feedback Mechanisms.
What is a “set point” when talking about Feedback Mechanisms ? What happens when the set point deviates from the desired normal?
It is a range of values of variable that does not bring about a response (considered as the normal range) (or desired range) and when that set point changes the Nervous or endocrine system reacts to try and bring the set point back to normal.
What types of feedback are there in Feedback mechanisms?
Positive Feedback and Negative feedback
What is negative feedback when talking about feedback mechanisms?
it is the most common type of feedback and it’s where the variable is brought back to the set point. i.e. in opposite direction of the change that triggered the response
How does the body go from realizing that internal tempature is too high and cool off the body?
the hypothalamus thermostat cells (R) detect high temp. (stimulus
Brain makes the body sweat by relaxing the smooth muscles in the blood vessels casing the sweat glands to secrete sweat and body cools down.
what is Positive Feedback when talking about Feedback Mechanisms?
Less common - NOT homeostatic
It intensifies the input (ex:labour)
