midterm 1 Flashcards
define physiology
the study of the normal functioning of a living organism and its component parts, including all its chemical and physical processes
what are emergent properties?
properties of a complex system that cannot be explained by a knowledge of a system’s individual components ex. emotion or intelligence in humans cannot be predicted from knowing the individual properties of nerve cells
what are the levels of organization studied in physiology?
chemistry (atoms,molecules), molecular biology (cells), cell biology (tissues), physiology (organs, organ systems, organisms, populations of species), ecology (ecosystems of diff species, biosphere)
what are the 10 organ systems of the body?
integumentary, respiratory, digestive, nervous, endocrine, circulatory, urinary, musculoskeletal, reproductive, immune system
what is a function or teleological approach to physiology?
the “why” ex. why do red blood cells transport oxygen? cause cells need oxygen
what is the mechanistic approach to studying physiology?
the “how” ex. how do red blood cells transport oxygen? oxygen binds to hemoglobin molecules in RBCs
what is homeostasis?
the ability to maintain a stable internal environment (blood pressure, body temp, ion/molecule concentration, gas pressures etc.) despite expose to external variability, homeo- similar, stasis- condition
what is the law of mass balance?
the amount of substance in the body is to remain constant, any gain must be offset by equal loss ex. intake through intestine output by liver etc.
why is homeostasis not equal equilibrium?
body compartments are in a dynamic steady state in a stable disequilibrium to maintain the dynamic steady state
how does the local control system help maintain homeostasis?
active cells reduce O2 levels in tissue, active cells send local signals, O2 levels in tissue are restored
how does the reflex control system help maintain homeostasis?
uses long-distance signalling, any long distance pathway that uses the nervous, endocrine system or both ex. blood pressure
what do negative feedback loops do?
a pathway where the responses removes the signal- stabilizes a system, homeostatic, can restore initial state but cannot prevent initial disturbance
what do positive feedback loops do?
reinforce a stimulus to drive the system away from a normal value rather than removing it, requires intervention, not homeostatic
what is feedforward control?
a few reflexes have evolved that allow the body to predict a change is about to occur
what are biorhythms?
variables that change predictably and create repeating patterns or cycles of change, may create an anticipatory response to predictable environment changes
what are the 4 main functions of the cell membrane?
physical isolation, regulation of exchange with the environment, communication between the cell and its environment, structural support
why are cell membranes different depending on the cell?
the more metabolically active the membrane, the more protein it contains
what are the 3 types of lipids found in the cell membrane?
phospholipid (major lipid), sphingolipids (lipid rafts), cholesterol (increases viscosity, decreases permeability)
what are integral proteins and what do they do?
include transmembrane proteins and lipid anchored proteins that are membrane receptors, cell adhesion molecules, transmembrane movement, and mediators of intracellular signaling
what are peripheral proteins and what do they do?
attach to integral proteins, loosely attached to phospholipid head to participate in intracellular signaling and form submembraneous cytoskeleton
what do lipid rafts do?
contain an abundance of proteins important in cell signal transduction
what are glycolipids?
carbs that serve as recognition sites for cell to cell interactions
what are glycoproteins?
carbs that help with structure, transport, and immunity
what does cholesterol in the cell membrane do?
add flexibility to make membrane impermeable to small water-soluble substances
what are the 2 body fluid compartments?
ICF (cells, 2/3 of the total body water volume), ECF (blood and interstitial fluid, 1/3 of the total body water volume)
how is the body in osmotic equilibrium?
fluid concentration are equal
what is osmosis?
the movement of water across a membrane in response to a solute concentration gradient
what are aquaporin channels for and how many are there?
13 channels, involved in short and long term water regulation of water balance
what is osmolarity?
describes the number of particles in a solution, isosmotic (equal), hyperosmotic (greater than), hyposmotic (less than)
what is tonicity?
describes cell volume changes and how that solution would affect cell volume if allowed to come to equilibrium
what are the differences between tonicity and osmolarity?
osmolarity describes the number and can be measured, tonicity has no units. osmolarity compares 2 solutions, tonicity compares a solution and a cell. tonicity depends on the concentration non-penetrating solutes
what are the different kinds of active transport?
vesicular transport (ATP), exocytosis, endocytosis, phagocytosis, primary active transport and secondary active transport
what are the different kinds of passive transport?
facilitated diffusion, ion channel, aquaporin channel, and simple diffusion
what is diffusion?
the movement of molecules from an area of higher concentration to an are of lower concentration until equilibrium using kinetic energy
what is simple diffusion for?
small uncharged molecules (O2, CO2, NH3,) it is faster if the surface area is larger, the membrane is thinner, the gradient is larger, the membrane is more permeable
why do molecules use protein mediated transport?
most molecules in the body are either lipophobic or electrically charged and cannot cross the membrane by simple diffusion- facilitated diffusion or active transport
traits of channel proteins
made of protein subunits that create a cluster of cylinders with pore in the center, open channels, facilitated diffusion
what are carrier proteins?
large complex proteins that change conformation to move molecules slowly, and can move small organic molecules that cannot pass through channels
what is facilitated diffusion?
molecules and ions appear to move in and out of a cell by diffusion but cannot cross the lipid bilayer by simple diffusion, therefore use channels or carrier proteins to move down their concentration gradient, no energy required, and stop once equilibrium is reached
what is active transport?
move molecules against their concentrations gradients from area of low concentration to an area of high concentration, support state of disequilibrium, requires energy, uses carrier proteins
what is primary active transport?
energy to move molecule comes directly from hydrolyzing ATP (3 Na+ out, 2 K+ in)
what is secondary active transport?
uses the potential energy stored in the concentration gradient of one molecule (Na+) to push another molecule against their concentration gradient
what is specificity?
refers to the ability of a transporter to move one molecule or a related group of molecules
what is competition?
a carrier may move several members of a group of substances but these substances compete with one another, carrier may have a preference for one family member
what is saturation?
rate of transport depends on concentration and number of transporters, transport increases with increasing concentration until transport max. is reached
what is phagocytosis?
creates vesicles using cytoskeleton, requires ATP to move the cytoskeleton for intracellular transport of the vesicle
endocytosis
membrane indents, vesicles are much smaller, requires ATP, pinocytosis allows ECF to enter (non selective), receptor mediated transport (selective)
exocytosis
vesicles can be filled with large lipophobic molecules such as proteins synthesized in the cell or wastes left behind by lysosomes after intracellular digestion, can occur continuously, or intermittently when initiated by some sort of signal, requires ATP, can be regulated by Ca2+