Basic Physiology & Homeostasis Flashcards
(43 cards)
What are the five essential requirements for life?
Water, Nutrients, Oxygen, Temperature, and Pressure.
What are the two types of metabolism related to energy?
Anabolism: Builds molecules, requires energy (ATP).
Catabolism: Breaks molecules, releases energy (produces ATP).
What is the basic function of a living organism in terms of energy?
To ingest energy/molecules and convert them to fuel for movement, maintenance, and structure.
Define homeostasis.
The maintenance of a stable internal environment (e.g., pH, temperature, fluid levels) necessary for life.
What is the difference between equilibrium and steady state?
Equilibrium: No net transfer; no energy required.
Steady state: Constant internal conditions maintained with energy input.
What are the components of a feedback loop?
Sensor (Receptor)
Control Center
Effector
What is a negative feedback loop?
A loop that reduces or shuts off the original stimulus to maintain homeostasis.
Give an example of a negative feedback loop.
Sweating to cool the body when overheated; vasodilation during heat exposure.
What is a positive feedback loop?
A loop that amplifies a change until a specific end point is reached.
Name two physiological examples of positive feedback loops.
Childbirth (oxytocin release)
Blood clotting cascade
What are the fluid compartments in the body?
ICF (Intracellular Fluid): 2/3 of TBW
ECF (Extracellular Fluid): 1/3 of TBW → includes interstitial fluid and plasma (intravascular)
What is the typical ion concentration difference between ICF and ECF?
ICF: High K⁺, low Na⁺
ECF: High Na⁺, low K⁺
Why is ATP important for cellular function?
It stores and releases energy needed for cellular processes (e.g., transport, synthesis, movement).
What happens during cold exposure as part of homeostasis?
Vasoconstriction, shivering, increased metabolism via thyroid hormone and adrenaline.
What are the levels of organization in the human body (from smallest to largest)?
Carbon atom → DNA molecule → Organelle → Cell → Tissue → Organ → Organ system → Organism
Why is integration of all body levels important?
Because it allows the body to function as a whole to perform complex tasks.
What are humans classified as in terms of biological complexity?
Meta-organisms – composed of human cells and trillions of symbiotic microbes.
What are the four major types of biological macromolecules?
Carbohydrates, Lipids, Proteins, Nucleic Acids
What is the general formula for carbohydrates?
(CH₂O)ₙ
What are the main functions of carbohydrates?
Energy source (glucose for ATP)
Structural role (cell membranes: glycoproteins & glycolipids)
Why are lipids hydrophobic?
They are mostly nonpolar hydrocarbons.
List 3 major functions of lipids.
Energy storage (triglycerides)
Structural (phospholipid bilayer in membranes)
Insulation & hormone signaling (e.g., steroid hormones)
What determines a protein’s function?
Its 3D structure, which is determined by the amino acid sequence.
