measures of central tendency (mean, median, mode) + measure of dispersion (range, variance, standard deviation, standard error)
parameter vs. frequency... 68, 95, 99% within tha +/- 1, 2, 3 standard deviations (delta/ s) of the mean.
"r from -1.0 to +1.0"... assumes no cause-and-effect relationship b/w the variables... association??... measures the direction and strength of the linear relationship...
accuracy & precision
nearness of a measurement to the actual value of the variable & closeness of repeated measurements of the same quintity
dynamic internal constancy... Claude Bernard "an organism remains constant despite changes in the external environment surrounding the organism"
The body maintains homeostasis with a set of sensors and physiological mechanisms that can be activated or inhibited accordingly.
Any deviations from the set point will be detected by the sensors which will stimulate mechanisms to return the body to the set point.
Feedback mechanisms = feedback loops... response becomes the stimulus!
(stimulus) -- sensors (single cells/ multiple cells in a gland or organ) --integrating center--effectors -- response
responses are in the "opposite" from the initial stimulus/ disturbance in homeostasis... keeping the right body temp.
responses are in the "same" as the initial stimulus/ disturbance in homeostasis... blood clotting & the enhancement of labor contractions during birth
Rate of diffusion is dependent upon...
(1) conc. gradient (2) permeability & thickness of the semipermeable membranes (3) surface are of the semipermeable membranes (4) size of the molecules diffusin (5) temperature
Diffusion with no energy required from high conc. to low conc.
diffusion, osmosis (MW of water = 18g/mol) , facilitated diffusion (protein transporter)
net movement of water = solvent from an area of low solution conc. to an area of high solute conc.
tendency of a solution to elicit osmosis... # of molecules (such as NaCl) i.e. 1 Molar of anything contains 6.02*10 to the 23 molecules
ion gradients across the human cell membranes are established by...
active solute pumps using ATP... ex) Na+/K+ pump that moves both ions against their conc. gradients
Na+/K+ pump moves...
3 Na+ out of the cell and 2K+ into the cell for every 1 ATP molecule... maintains both a conc. gradient AND an electrical gradient.
relative diff. in the # of Na+ and K+ present in the intra- and extracellular fluids... more K+ inside the cell and more Na+ out side the cell
resting membrane potential
-70 mV for a nerve cell. V across the cell membrane while the cell is at rest.
Resting membrane potential is created because of...
(1) diff. in the ion concentrations on the O vs. I of the cell membrane (2) relative permeability of the plasma membrane to Na+ and K+ ions (3) conc. gradient of Cl-
equilibrium potential (= electrical potential needed to balance an ionic conc. gradient so that the net flux of that ion is 0) for each ion such as Na+
voltage-gated Na+ and K+ channels
when a neuron receives an electrical stimulus, it induces voltage-gated Na+ and K+ channels in the cell membrane to open
Na+ channels have
a faster rate of response to voltage changes across the membrane and an extra intracellular structure known as an inactivation gate which limits the influx of Na+ ions into the cell by blocking the channel shortly after depolarization opens it...
-55mV... If the stimulus opens enough voltage-gated Na+ channels to depolarize a neuron to its threshold voltage then an action potential can be generated.
amplitude of depolarization
does not depend on the stimulus strength/duration but the chemical properties of the voltage-gated ion channels & the conc. and electrical gradients of the cell
def. action potential
a brief all-or-none depolarization of the cell membrane... has a refractory period and a threshold
def. resting membrane potential
steady transmembrane potential of a cell that is not producing an electric signal
time during which an excitable membrane does not respond to a stimulus that normally causes response
def. equilibrium potential
at the eq. potential for an ion, there is no net movement of the ion because the opposing fluxes are equal, and the potential will undergo no further change...
absolute refractory period
time period following an action potential during which a second action potential cannot be generated, no matter how strong the stimulus
relative refractory period
a second potential may be generated, but it requires a stimulus stronger than the one that generated the first action potential
compound action potential
sum of the all the action potentials... voltage change across the nerve rather than a single axon
EPSP (excitatory postsynaptic potential)
electrical response in the postsynaptic cell at an excitatory synapse
IPSP (inhibitory postsynaptic potential)
electrical response in the postsynaptic cel atan inhibitory synapse
the postsynaptic cell's potential is the result of...
temporal and spatial summation of the EPSPs and IPSPs at the many active excitatory and inhibitory synapses on the cell.
As the experiment is repeated enough times, the unlearned response will become a learned response!
unlearned response times using an auditory cue
sensory receptors -- sensory/ afferent neurons (dorsal root) -- synapses in the spinal cord -- motor/efferent neurons (ventral root) -- effector
Effectors of somatic reflexes are skeletal muscles which are usually under voluntary control and the effect is always
excitatory = causing a muscle contraction...ex) patellar tendon reflex
autonomic nervous system reflexes assist in regulating the activity of physiological systems such as endocrine, cardiovascular, repiratory, urinary, and digestive systems which are NOT under voluntary control and the effect is
either stimulatory OR inhibitory, depending on the neurotransimitter released by the efferent neuron and the receptor type present on the effector.
Reflec occur very quickly in response to a stimulus because...
processing by higher brain centers is not required for the reflexive action.
The patellar tendon stretch reflex is...
an ipsilateral monosynaptic reflex, in which the sensory neuron synpases DIRECTLY onto the motor neuron... no interneurons!!
in stretch reflexes, the antagonistic muscle group is simultaneously inhibited from contracting.
In the patellar tendon stretch reflex, some afferent neurons synapse on inhibitory interneurons... this part of a stretch reflex is
polysynaptic!! includes interneurons.
Meissner's corpuscle, Merkle's corpuscle, Pacinian corpuscle, and ruffini corpuscle
Sensitivity of a certain area depends on...
(1) density (2) receptive fields of somatic sensory receptors
how do sound waves get transmitted?
external auditory canal -- tympanic membrane -- ossicles (malleus, incus, and stapes) -- cochlea (sterocilia of hair cells transduce mechanical stimulus of sound pressure waves into nerve impulses)
At the infinite distans = 20 ft.
the light entering the eye from an object are parallel and naturally focused on the fovea centralis and the lens is in its RELAXED state
hyperopia = farsightedness
short eyeball/ images of near objects converge at a point behind the retina... corrected with a convex/ converging (+) lens
myopia = nearsightedness
long eyeball/ images of far objects focus at a point before the retina.. corrected with a concave/ diverging lenses (-)
=1/ focal length (from lens to the focal point on the retina) in meters... measures refractive power of a lens... visual acuity
hearing inability due to impaired conduction of sound waves in the middle ear/ cochlea
hearing inability due to impaired transduction from the cochlea to the auditory complex
Weber's test detects...
sound perceived by the damaged ear due to bone conduction is not dampened and seems louder --> conduction deafness