PhysioEx 3

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122 terms

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%

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