anatomy
study of the structure and description of the human body
physisology
study of biological functions and processes of the human body under basal conditions
basal
normal
cellular physiology
study of the biochemical and biophysical processes occurring within cells
systemic physiology
study of the regulation of physiological processes within the body by homeostatic reflexes
pathophysiology
study of abnormal biochemical and biophysical processes that occur in disease
homeostasis
the dynamic constancy of the internal physiological environment while buffering the challenges of the external environment
Feedback control mechanism steps
stimulus produces change in variable
change detected by receptor/sensor
input: information sent along afferent pathway
output: information sent along efferent pathway
response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis
Lay terms of feedback mechanism
stimulus, receptor, control center, effector, response
Negative feedback system
response of the control system is negative or opposing to the stimulus; most systems in the body
Example of negative feedback system
Stimulus: weather increased body temp Receptor: thermoreceptor Control center: hypothalamus Effector: sweat glands Response: sweating
positive feedback system
the response of the control system is positive or promoting the stimulus; act to amplify the initial response to the stimulus; continues until the stimulus is removed
Positive feedback system examples
child birth and blood coagulation
plasma membrane
serves as an external cell barrier that is selectively permeable
amphipathic
both hydrophyllic and hydrophobic
phosphate heads
hydrophillic
fatty acid tails
hydrophobic
molecules that can cross plasma membrane without assistance
small uncharged molecules
non-polar molecules
fatty molecules
water (slowly; fast transfer requires mechanism)
Passive transport
substance moves down its concentration gradient, from area of high concentration to low concentration
Simple diffusion
natural movement from high to low concentrations; unassisted transport (no integral protein)
Facilitated diffusion
substances passively moves down its concentration gradient with the help of a protein molecule
channel mediated
special transport proteins create hydrophilic tunnels in the lipid bilayer; facilitate the transport of small, polar molecules and ions
carrier mediated
special transport proteins carry the substance across; facilitate transport of large polar molecules
active transport
transport of a substance across a cell membrane against the concentration gradient
primary active transport
carrier proteins pump the molecules against the concentration gradient; direct use of cellular energy
secondary active transport
downhill movement of one molecule drives the uphill movement of another molecule; indirect use of energy (uses established concentration gradient to power its transport)
vesicular transport
bulk transport of substances into or out of the cell
endocytosis
substances are taken into the cell by modifying the plasma membrane structure
phagocytosis
cell eating; cell engulfs large particle by forming projecting psuedopods around it and enclosing it within the membrane sac (phagosome)
pinocytosis
cell drinking; enfolding of plasma membrane carries a drop of extracellular fluid containing solutes into the cell in tiny membrane-bound vesicle
exocytosis
substances are released from the cell into the extracellular environment; most secretion processes
osmosis
passive diffusion of water against concentration gradient through plasma membrane (hypotonic to hypertonic)
hypotonic solution
lower solute concentration, higher water concentration, net movement of water out of this side
hypertonic
higher solute concentration, lower water concentration, net movement of water toward this side
isotonic
equal solute and solvent concentration on both sides; water molecules continue to cross membrane but no net movement
tonicity
measure of potential difference in osmotic pressure gradient of two solutions separated by a semipermeable membrane
outside of cell is hypertonic to inside of cell
cause the blood to shrivel
outside of cell is hypotonic to inside of cell
causes the blood to lyse
epigenetics
mechanisms by which genes can be switched on and off but genes themselves are not altered