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122 terms

PhysioEx 3

STUDY
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diffusion
the movement of molecules from an area of higher concentration to an area of lower concentration as a result of random thermal motion
facilitated diffusion
the movement of molecules across a selectively permeable membrane with the aid of specialized transport proteins
osmosis
the transport of water across a semipermeable membrane
active transport
the movement of molecules across a membrane that requires the expenditure of cellular energy (ATP)
hypotonic
term used to describe a solution that has a lower concentration of solutes compared to another solution
isotonic
term used to describe a solution that have the same concentration of solutes relative to one another
hypertonic
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
What is the equation for Fick's First Law of Diffusion?
J = -DA△c/△x
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.
motor unit
consists of a motor neuron & all of the muscle fibers it innervates. Directs muscles when & when not to contract.
twitch
the mechanical response to a single action potential.
threshold
the minimal stimulus needed to cause a depolarization of the muscle plasma membrane.
treppe
the progressive increase in force generated when a muscle is stimulated at a sufficiently high frequency.
summation
the result of stimuli arriving one after another so quickly that twitches overlap.
tetanus
plateau that results when a muscle is stimulated frequently over a prolonged period of time.
fatigue
decline in a muscle's ability to maintain a constant force of contraction after prolonged, repetitive stimulation.
isometric contraction
contraction in which a muscle is attempting to move a load greater than the force generated by the muscle.
isotonic contraction
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.
What factor might be the high-intensity exercise fatigue?
Lactic acid buildup in muscles.
What factor might be the low-intensity exercise fatigue?
Depletion of energy reserves.
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 is the key variable in an isometric contraction?
muscle length
maximal stimulus
the stimulus beyond which there are no further increase in force.
What has happened in the muscle when the maximal stimulus is achieved?
All the individual nerve fibers have been stimulated & responding all-or-none.
stimulus intensity
increase in the force of a stimulus (e.g. increased voltage)
stimulus frequency
refers to how often stimulus is applied.
threshold
minimal stimulus needed to elicit an AP
sodium
major cation found outside of a cell
potassium
major cation found inside of a cell
RMP
refers to a membrane potential of about -70mv
absolute refractory period
period when cell membrane is totally insensitive to additional stimuli, regardless of the stimulus force applied.
depolarization
reversal of membrane potential due to influx of sodium ions.
What are the 2 major physiological properties neurons, as with other excitable cells of the body have?
irritability & conductivity
sodium-potassium pump
a neuron has a + charge on the outer surface of the cell membrane due in part to the action of an active transport system.
Which way does sodium-potassium pump move sodium?
out of the cell
Which way does sodium-potassium pump move potassium?
into the cell
intracellular proteins
remains - due to intracellular pH & keep the inside of the cell membrane negative.
Action Potential
large reversal of the membrane polarity that occurs when the membrane depolarizes to threshold.
irritability
ability to respond to stimuli & convert them into nerve impulses.
conductivity
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)
What is the effect of ether on eliciting an AP?
no nerve response
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.
Ovary secretes
estrogen
thyroid gland secretes
thyroxine
pancreas secretes
insulin
pituitary gland secretes
TSH
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 TSH
thyroid gland; control production of thyroxine.
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.
What are tropic hormones?
hormones that stimulate or inhibit the secretion of other hormones.
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.
glucose standard curve
point of reference for converting optical density readings.
FPG value less than 110mg/dl
dx as normal range in glucose reading
FPG value greater than or equal to 126mg/dl
dx as diabetes in glucose reading
FPG value b/w 110-126mg/dl
dx as impairment or borderline impairment in glucose reading
2hr. OGTT level b/w 140-200mg/dl
impaired glucose tolerance
2hr OGTT level aboe 200mg/dl
confirms diabetes dx
Which type of DM is the pt. at risk if dx w/ impaired glucose tolerance?
Type II DM
cortisol
hormone secreted by the adrenal cortex, is key to the long-term regulation of stress. stimulated by ACTH.
ACTH
hormone released by the anterior pituitary. stimulated by a hypothalamic hormone, CRH, inhibited by cortisol.
high cortisol
greater than or equal to 23mcg/dl
low cortisol
less than 5mcg/dl
high ACTH
greater than or equal to 80 pg/ml
low ACTH
less than 20 pg/ml
cushing's syndrome (primary hypercortisolism)
high cortisol level, low ACTH level
cushing's disease (secondary hypercortisolism)
high cortisol level, high ACTH level
Iatrogenic Cushing's syndrome
high cortisol level, low ACTH level (physician induced)
Addison's disease (primary adrenal insufficiency)
low cortisol level, high ACTH level
Secondary adrenal insufficiency (hypopituitarism)
low cortisol level, low ACTH level
protein activity can be changed by...?
alter gene expression, phosphorylation of a protein to activate/deactivate it.
hormones are released in 3 ways
hormonal, neural, or humoral
hormonal
hormone released by another endocrine gland
neural
hormone released by nervous system. release of epinephrine from the adrenal medulla.
humoral
hormone released by body fluid
negative feedback
results in hormonal homeostasis, that is the maintenance of hormone levels within a particular appropriate physiological range
CRH
hormone that stimulates ACTH secretion, inhibited by cortisol
Ratio/fraction of the blood in the normal adult human
1/12
avg. blood volume for males
30ml/lb
avg. blood volume for females
27.5ml/lb
How many RBC are in each cubic millimeter of adult male blood?
5 million
How many RBC are in each cubic millimeter of adult female blood?
4.5 million
polycythemia
excess count in RBC
anemia
low count in RBC
hemocytometer slide
forms a roof that is 1/10 mm above the grid surface
Gower's/Hayem's solution
diluent for RBC
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)
Turk's solution
diluent for WBC, contains an acid that lyses the RBC's & a gentian violet stain that stains the nuclei of WBC's
convert lbs to gms to find out gm wt. of blood
[ weight(lbs) x 454g/lb ]/ 12 = gm wt. of blood
anisocytosis
abnormal sizes of RBCs
poikilocytosis
abnormal shapes of RBCs
what morphology changes are seen in Sickle Cell Anemia?
poikilocytosis, normochromic
what morphology changes are seen in Pernicious Anemia?
anisocytosis-macrocytic, normochromic
what morphology changes are seen in Iron Deficiency Anemia/Cooley's Anemia/Thalassemia major?
anisocytosis-microcytic, hypochromic
what morphology changes are seen in Hereditary Spherocytosis?
anisocytosis-microcytic, normochromic
leukopenia
low count in WBC
leukocytosis
excess count in WBC
hypochromic
RBC's paler than normal, low in hgb
microcytic
abnormally small RBCs
normochromic
normal color w/ a normal concentration of hgb
macrocytic
abnormally large RBCs
megaloblastic
large & abnormally nucleated RBCs
One gram of hgb will bing with about how many ml of oxygen?
1.34ml
How many gm% of hgb does the avg. person carries?
about 15gm%