the movement of molecules from an area of higher concentration to an area of lower concentration as a result of random thermal motion
the movement of molecules across a selectively permeable membrane with the aid of specialized transport proteins
the movement of molecules across a membrane that requires the expenditure of cellular energy (ATP)
term used to describe a solution that has a lower concentration of solutes compared to another solution
term used to describe a solution that have the same concentration of solutes relative to one another
term used to describe a solution that has a higher concentration of solutes compared to another solution
List 3 examples of passive transport mechanisms
osmosis, simple diffusion, and facilitated diffusion
Why is it important that Urea be removed from diabetic patients?
In a diabetic pt, kidney fxn is compromised & thus the body cannot effectively remove urea (a waste product) from the bloodstream. Too much urea in the blood will lead to nitrogen narcosis & eventually death.
How can concentration of water in a solution be decreased?
Increasing the solute conc. will decrease the water conc. b/c the solute conc. is the inverse of the solvent conc.
Suppose that a membrane separates a solution of higher osmolarity and a solution of lower osmolarity. To prevent osmotic flow of water across the membrane, pressure should be applied to which of the two solutions?
Higher osmolarity. The solution w/ higher osmolarity has a high conc. of solute & low conc. of water; therefore, this solution would need to have pressure applied in order to block waterfront coming in from the solution of lower osmolarity.
What change in cell volume will occur when a cell is placed in a hypotonic solution?
Cell will expand. Water will move from the solution into the cell & if enough water enters the cell, the cell will eventually burst.
What change in cell volume will occur when a cell is placed in a hypertonic solution?
Water will move out of the cell, causing the cell to become crenated.
consists of a motor neuron & all of the muscle fibers it innervates. Directs muscles when & when not to contract.
the progressive increase in force generated when a muscle is stimulated at a sufficiently high frequency.
plateau that results when a muscle is stimulated frequently over a prolonged period of time.
decline in a muscle's ability to maintain a constant force of contraction after prolonged, repetitive stimulation.
contraction in which a muscle is attempting to move a load greater than the force generated by the muscle.
contraction in which the force generated by the muscle is constant & greater than or equal to the load being moved.
Describe the process of excitation-contraction coupling.
An AP in a motor neuron triggers the release of Ach. Ach diffuses into the sarcolemma & binds to receptors in the muscle cell. The resulting change in ion permeability triggers a depolarization of the plasma membrane called an end plate potential. The end plate potential triggers a series of events that results in the contraction of a muscle cell.
Describe the three phases of a muscle "twitch"
Latent period: period of time that elapses b/w the generation of an AP in a muscle cell & the start of a contraction. Contraction phase: a period of time that starts at the end of the latent period & ends when muscle tension peaks. Relaxation phase: period of time from peak tension until the end of muscle contraction.
In fatigue, what happens to force production over time?
Force falls b/c muscle cell's ATP is used up faster than it's produced.
What has happened in the muscle when the maximal stimulus is achieved?
All the individual nerve fibers have been stimulated & responding all-or-none.
absolute refractory period
period when cell membrane is totally insensitive to additional stimuli, regardless of the stimulus force applied.
What are the 2 major physiological properties neurons, as with other excitable cells of the body have?
irritability & conductivity
a neuron has a + charge on the outer surface of the cell membrane due in part to the action of an active transport system.
remains - due to intracellular pH & keep the inside of the cell membrane negative.
large reversal of the membrane polarity that occurs when the membrane depolarizes to threshold.
ability to transmit an impulse (to take the neural impulse & pass it along the cell membrane)
What are the types of stimulus are there to study nerve physiology in the laboratory?
Electrical, Mechanical, Chemical, & Thermal Stimulation. (They are all capable of generating on AP in a nerve)
Does the addition of ether to the nerve cause any permanent alteration in neural response?
No, has no lasting effect. Ether impairs the ability of nerve fibers to function. (Blocks nerve transmission)
What is the effect of curare on eliciting an AP?
Curare affects the synapse rather than nerve propagation. b/c curare works by blocking synaptic transmissions so that neural impulses do not travel from neuron to neuron.
What is the effect of lidocaine on eliciting an AP?
Blocks sodium ion channels from opening, inhibiting AP.
What is the relationship b/w size of a nerve and conduction velocity?
The larger the nerve, the faster the conduction velocity.
Target tissue & specific action of thyroxine
all cells of the body; maintains metabolism & body heat.
Target tissue & specific action of estrogen
uterus; enables the uterus to grow & develop;
acts on osteoblasts to secrete OPG, a decoy receptor for RANK-L and inhibits osteoclast activity.
Target tissue & specific action of insulin
blood cells; regulation of blood glucose levels & absorb glucose from the blood stream.
Target tissue & specific action of FSH
ovaries; to get ovarian follicles to develop so that they may be ovulated & potentially fertilized.
What is the role of hypothalamus in the production of thyroxine & TSH?
It is a primary endocrine gland that secretes several hormones affecting the pituitary gland.
How does TRH travel from the hypothalamus to the pituitary gland?
via the hypothalamic-pituitary portal system.
Why didn't the administration of TSH have any effect on the metabolic rate of the thyroidectomized rat?
The thryoid was removed from the rate & TSH travels to the thyroid to produce thryoxine. If the thryoid is not there, TSH's effect would be null.
Why didn't the administration of propylthiouracil have any effect on the metabolic rate of either the thyroidectomized rat or the hypophysectomized rat?
The rat needs both the pituitary glands as well as the thyroid gland to produce thyroxine. PTU inhibits the production of the thyroxine, but thyroxine is already not being produced in this rat due to the absence of the pituitary &/or thyroid glands.
What effect did the administration of estrogen injections have on the estrogen-treated rat?
Increase in VBD, from osteoporosis to osteopenia.
What effect did the administration of calcitonin injections have on the calcitonin-treated rat?
Slight increase in VBD, but remains osteoporosis.
hormone secreted by the adrenal cortex, is key to the long-term regulation of stress. stimulated by ACTH.
hormone released by the anterior pituitary. stimulated by a hypothalamic hormone, CRH, inhibited by cortisol.
protein activity can be changed by...?
alter gene expression, phosphorylation of a protein to activate/deactivate it.
results in hormonal homeostasis, that is the maintenance of hormone levels within a particular appropriate physiological range
Equation to calculate the original number of RBCs in 1 cu mm (method 1)
cell count from all 5 squares x dilution factor/ # of squares counted x vol. of individual square
Equation to calculate the original number of RBCs in 1 cu mm (method 2)
cell count ( dilution x area x depth)
diluent for WBC, contains an acid that lyses the RBC's & a gentian violet stain that stains the nuclei of WBC's
what morphology changes are seen in Iron Deficiency Anemia/Cooley's Anemia/Thalassemia major?