Lecture 1: Physiology Overview Flashcards
Fluid components, organ systems, homeostasis, and feedback systems.
What is physiology?
The study of the normal functions/state of the body.
To “get” physiology you have to think of the body on the level of
Cells; Cell biology
About how many cells are in the human body, and what percentage of cells are Red Blood Cells versus everything else?
100 trillion; 25% RBC and 75% everything else
What is homeostasis?
Maintaining a constant environment on the inside while keeping it separate from the outside.
The “standard person” is ___ percent water
60%
What are the two fluid compartments of the human body?
Extracellular fluid (ECF) and Intracellular fluid (ICF)
Where is extracellular fluid located?
Outside of the cell
What is extracellular fluid composed of?
150 mM Na+
5 mM K+
108 mM Cl-
pH 7.4
What are the two subcompartments of extracellular fluid?
Blood and interstitial fluid.
The fluid component of the blood is called
Plasma
This surrounds all cells not in the blood
Interstitial fluid
Where do the two subcompartments of the ECF, blood plasma and interstitial fluid, meet?
Capillaries
Extracellular fluid makes up what fraction of the body’s water content?
1/3
Where is intracellular fluid located?
Inside of the cell
What is intracellular fluid composed of?
150 mM K+
5 mM Na+
Intracellular fluid trades molecules with extracellular fluid via
Na+/K+ pumps or pores
Intracellular fluid makes up what fraction of the body’s water content?
2/3
What is the principal component of the cytosol/cytoplasm?
Intracellular fluid
What are the two major types of control systems?
Positive and negative feedback.
Which control system is more common?
Negative feedback
What is negative feedback? Give an example
A change that drives a counterchange.
Example: Regulation of body temperature. When you are cold, your body shivers in order to generate heat. When you are hot, your body sweats to cool you down.
What is positive feedback? Give an example
Positive feedback is a change that drives itself. It is when the product of a reaction leads to an increase in that reaction.
Example: Childbirth. Baby puts pressure on the cervix which causes contractions. Contractions lead to more pressure on the cervix. The cycle continues until the baby comes out.
