Unit 1: Homeostasis & the Cell Flashcards
Define physiology.
The study of how systems function in a living organism.
Define homeostasis.
The maintenance of relatively stable conditions within the internal environment (body temp, blood sugar levels, blood pH, oxygen and carbon dioxide levels, blood pressure, electrolyte balance, water balance).
What are the components of a negative feedback loop?
Control centre (develops a plan to maintain/restore), effector (responds to the plan), regulated variable (regulated through negative feedback loop), sensor (monitors interval environment).
How do negative feedback loops maintain homeostasis?
They maintain the variable within a normal range and once the variable reaches its ideal level, it shuts off. The event/effect of a reaction eventually loops back.
Define a positive feedback loop.
An increase of both variables. An external event needs to occur in order to break/shut off the loop.
What is the organizational hierarchy of the body?
Atoms, macromolecules, organelles, cells/tissues/organs, organ systems, organism.
What are the 3 body fluid compartments?
Intracellular fluid, Interstitial fluid, blood plasma fluid.
What type of body fluid makes up the majority of the fluid found in the cell?
Intracellular fluid (67%).
True or false.
Interstitial fluid has high concentration levels of K.
False. Interstitial fluid has high levels of Na, Ca, and Cl. Intracellular fluid has high levels of K.
What is the function of blood plasma fluid?
Allows red and white cells and platelets to circulate around the body. It makes 6.6% of fluid in the body.
Which ions are more concentrated outside the cell, and which ions are more concentrated in the cell?
Na, Ca and Cl are more concentrated outside the cell. K is more concentrated in the cell (salty banana).
What is the ratio of Na and K ions being pumped into and out of the cell via the Na/K pump?
3 Na in, 2 K out.
What are the 6 functions of membrane proteins?
Cell identity marker (cellular identification), cell surface receptor (neurotransmitters and hormones), ion channels (Na/K pump), transporters (movement of molecules across a membrane), enzymes (catalyze reaction, facilitate processes), cell-cell adhesion proteins (cell-cell interactions).
What is the difference between facilitated diffusion, active transport and secondary active transport?
Facilitated diffusion allows for passive movements of solutes along their concentration gradient. Active transport is the movement of molecules against their concentration gradient using ATP. Secondary active transport utilizes ion gradients to transport molecules across membranes, driven by energy from gradient-established primary active transport.
What are the 5 major ways substances cross the membrane?
Simple diffusion (high to low concentration), facilitated diffusion (the movement of the molecule along it concentration gradient that requires the help of a transport protein), pumps (against concentration gradient), endocytosis, exocytosis.
