Physiology lecture test 1 modules
Hemorrhage would tend to increase the secretion of which of the following?
ADH, aldosterone, and erythropoietin
In comparing a solution to a fluid in a cell, a hypertonic solution always has ____________.
a higher concentration of non-penetrating solutes than that in the cell
Which of the following conditions would lead to the fastest rate of oxygen diffusion into a cell?
a large concentration gradient and a thin membrane
Chemical messengers that may require a carrier protein to move through the bloodstream include __________.
all answers are incorrect
Due to the similarities in chemical structure of dopamine, epinephrine, and norepinephrine, they can all be classified as __________.
amines and catecholamines
When insufficient water intake leads to dehydration, compensatory mechanisms to preserve plasma volume and homeostatic osmolarity include __________.
increasing the amount of water that is reabsorbed from the filtrate in the collecting duct
Angiotensin II leads to an alteration in kidney function by __________.
increasing water reabsorption from the collecting ducts and increasing sodium reabsorption along the distal tubules
When mean arterial pressure decreases, which of the following may increase in response?
ADH levels and water reabsorption
Intracellular calcium levels are kept in the submicromolar range (<10-6 molar) by which of the following mechanisms?
All answers are correct
Which of the following statements about G proteins is(are) false?
All answers are true and thus incorrect.
__________ are ligands that bind to receptors but do not produce a response.
Antagonists
Which of the following hormones will directly act on the collecting duct of the kidney to enhance the reabsorption of water?
Antidiuretic hormone
If a human drinks 200 ml of seawater, how will the body correct for the increase in plasma osmolarity?
By increasing the release of vasopressin
Which of the following interacts with receptors on the cell surface?
Catecholamines
__________ allow(s) the body to predict that a change is about to occur and start the __________ in anticipation of the change.
Feed forward control; response loop
Signal amplification can occur at the level of the __________.
G protein, protein kinase, and second messenger
When mean arterial pressure increases, which of the following may increase in response?
GFR and urine volume
If a person with a normal body fluid osmolarity drinks a large quantity of water, which of the following would occur if the kidneys could not excrete any of the water?
Hypervolemia and decreased plasma osmolarity
The level of calcium in the cytosol can be raised by activating __________.
IP3 and phosphlipase C
Which of the following statements provides an accurate comparison between facilitated diffusion and simple diffusion?
In both facilitated and simple diffusion, substances move down their concentration gradient.
Which of the following statements about dopamine is (are) true?
It is quickly degraded in the ICF after use.
An increase in which of the following would increase the rate of diffusion of oxygen molecules across pulmonary cell membranes?
Membrane surface area, the oxygen concentration inside the lung, and temperature
Which of the following statements about methods of cell-to-cell communication is false?
Most long-distance communication between cells is accomplished via chemicals known as autocrines and paracrines.
Which of the following molecules would not diffuse through cell membranes easily?
Na+ ions and glucose
If a cell's Vm = -70 mV and ENa+ = +50 mV, which way will Na+ ions move across the cell membrane?
Na+ ions will move into the cell.
__________ are substances that are released from neurosecretory cells but travel through the bloodstream to target tissues.
Neurohormones
Which of the following does not require the use of ATP?
Osmosis
Which of the following types of molecules would be most likely to pass through the plasma membrane by means of simple diffusion?
Oxygen - nonpolar
Passive membrane transport does not use energy in the form of ATP in order to move substances across biological membranes. That doesn't mean, however, that there is no energy used in the movement of ions across membranes. How would you classify the type of energy required in order for a neutral substance to move via either simple or facilitated diffusion?
Potential
Lipophobic chemical messengers are also hydrophilic. The following choices all describe lipophobic chemical messengers except one. Identify the exception.
Secretion is by diffusion.
Use the following scenario to answer the question. A beaker containing two fluid compartments separated by a semipermeable membrane is filled with distilled water. In compartment A you place 15 mM of NaCl and in compartment B you place 25 mM of NaCl. The membrane is permeable to both sodium and chloride. Initially, which side has the higher osmotic pressure? As time goes on will the water levels change,and if so how?
Side B has a higher osmotic pressure; the water levels will not change.
Which of the following statements about lipophilic hormones is false?
The effects of lipophilic messengers are short-lived.
Which of the following effects is (are) produced by epinephrine during exercise?
The heart beats faster and more forcefully.
Moderate changes in blood pressure (mean arterial pressure not less than 80 mmHg or greater than 180 mmHg) generally do not affect the glomerular filtration rate due to which known local control processes within the kidney?
The myogenic response and tubule-glomerular feedback
Facilitated diffusion differs from simple diffusion in what way(s)?
The rate of facilitated diffusion depends on the number of carriers in the membrane.
Which of the following statements about facilitated diffusion is(are) true?
The rate of facilitated diffusion is directly dependent on the number of carrier proteins for a solute and the rate of facilitated diffusion is directly dependent on the concentration gradient of the solute across the membrane.
Which of the following is not true of thirst?
Thirst is a physiological mechanism that maintains fluid and electrolyte balance.
In which of the following are receptor and transduction mechanisms contained within the same protein?
Tyrosine kinases and fast ligand-gated channels
In the absence of ADH, which of the following will decrease?
Urine osmolarity and aquaporin synthesis
The greatest electrical driving force on an ion to move into a cell is illustrated by which of the following examples?
Vm = -70 mV, ion = Ca2+ (ECa2+ = +110 mV)
Autocrine signals __________.
act on the same cell that secreted them
Cholera toxin raises cAMP levels in intestinal epithelial cells by directly __________.
activating G proteins
An osmotic gradient develops in the renal medulla because various parts of the loop of Henle differ from each other in which of the following characteristics?
all answers are correct
Cox-2 (cyclooxygenase 2) inhibitors, such as Vioxx and Celebrex, __________.
all answers are correct
Examples of eicosanoids include __________.
all answers are correct
Plasma solute concentration directly or indirectly affects __________.
all answers are correct
Responses to chemical messengers produced by target cells vary in magnitude according to __________.
all answers are correct
Steroid hormones are __________.
all answers are correct
Steroid hormones found in the human body are varied, but the manner in which they act on target cells is quite similar, in that they have an affinity for binding sites located __________.
all answers are correct
The plasma can gain or lose water and/or solutes by __________.
all answers are correct
The rate of diffusion, or flux, of particles across a membrane is dependent on __________.
all answers are correct
The signals controlling ADH release come from __________.
all answers are correct
When calcium enters a cell through ligand-gated channels, it may __________.
all answers are correct
In order for water to be absorbed by epithelial cells, __________.
aquaporins must be present in the cell membranes and the concentration of impermeable solutes must be higher on the inside of the cell
In contrast to fast ligand-gated channels, slow ligand-gated channels __________.
are directly linked to enzymes such as guanylate cyclase and interact with G proteins
The heart functions as a secondary endocrine organ because it secretes __________, which functions in the regulation of sodium reabsorption by the kidneys.
atrial natriuretic peptide (ANP)
Put the following events in the correct order: a. G protein activates phospholipase C. b. Ligand-bound receptor activates a G protein. c. PIP2 DAG + IP3. d. IP3 triggers calcium release from endoplasmic reticulum.
b, a, c, d
Lipophilic hormones __________.
bind to receptors inside the cytoplasm or nucleoplasm
Paracrines and autocrines ________.
both depend on diffusion as a means to reach their target cell and differ primarily in their targets
Put the following events in the correct order: a. Chemical messenger binds to receptor on the target cell. b. A response occurs in the target cell. c. Chemical messenger is secreted. d. Signal transduction occurs in the target cell.
c, a, d, b
When adenylate cyclase is activated, __________.
cAMP is formed by converting ATP to cAMP
The difference between carrier and channel proteins is that ________.
channel proteins create a continuous passage between intra- and extracellular compartments
Put the following events in the correct order: a) Angiotensin I is converted to angiotensin II. b) Renin is secreted by the granular cells. c) Aldosterone is released from the adrenal glands. d) Renin converts angiotensinogen into angiotensin I. e) Cells in the macula densa detect a decrease in the flow of fluid (or ion concentration) in the distal tubule.
e, b, d, a, c
During peptide synthesis, a propeptide may be found in the __________.
endoplasmic reticulum, Golgi apparatus, and secretory vesicle
Water toxicity occurs when __________.
extracellular fluids become hypotonic, causing brain cells to swell
Substances that promote inflammation include __________.
histamine and prostaglandins
An ACE (angiotensin converting enzyme) inhibitor would be used to treat __________.
hypertension since ACE inhibition will result in decreased secretion of anti-diuretic hormone and aldosterone
In people with diabetes mellitus, glucose is not being transported into cells at the normal rate. This buildup of glucose in the plasma causes the extracellular fluid to become __________.
hypertonic and hyperosmotic
A cell placed in a solution of unknown composition soon swelled up and burst, so the solution must have been __________ to the cell when it was originally placed in the solution.
hypotonic and of an undetermined relative osmolarity
Up regulation allows a target cell to __________.
increase the sensitivity of a target cell to a ligand
The effects of angiotensin II on the central nervous system are to __________.
increase thirst, increase cardiac output, and cause peripheral vasoconstriction
Which of the organ systems listed below is known for producing more focused, direct and the fastest responses from target cells?
nervous system
The second messenger DAG __________.
is membrane-bound
A cell containing 300 mOsm of non-penetrating solutes per liter is placed in a solution containing 200 mOsm of non-penetrating solutes per liter and 100 mOsm of the penetrating solute urea per liter. The solution can be said to be __________ with respect to the cell.
iso-osmotic and hypotonic
The organ(s) that regulate water loss to maintain water balance is (are) the __________.
kidneys
Filtrate leaving the loop of Henle is __________ in volume and __________ to the fluid entering the loop.
lower; hypo-osmotic
The primary function of the vasa recta is to __________.
maintain the medullary concentration gradient
If a patient is given an intravenous solution that is 0.9% NaCl (300 mOsm/L NaCl), his or her red blood cells will __________.
not change size or shape
The movement of water across the late distal tubule and collecting duct is __________.
passive, through channels called aquaporins, and driven by the medullary osmotic gradient
The cellular response to the second messenger cAMP can be inhibited by activating __________.
phosphodiesterase and Gi protein (inhibitory G protein)
People suffering from central diabetes insipidus (a disorder of the hypothalamus or pituitary gland) may have increased __________.
plasma osmolarity and urine volume
A vasopressin receptor antagonist would __________.
prevent membrane recycling in collecting duct cells
In contrast to the nervous system, the endocrine system __________.
produces long-lasting effects, has no direct anatomical link between the site of secretion and the target tissue, and often acts through G proteins
The fastest-acting membrane-bound receptors are __________.
proteins that contain both the receptor and the channel
With cystic fibrosis, breathing is difficult because __________.
the osmotic pressure of the fluid on the luminal side of the respiratory surface favors water transport out of cells and the movement of Cl- ions is impeded due to a lack of chloride transporters
Angiotensin II stimulates the __________.
release of aldosterone and release of ADH
An intracellular signaling molecule produced by the binding of a ligand to a membrane-bound receptor is called a __________.
second messenger
The interaction between chemical messengers and their receptors is similar to the interaction between __________.
substrates and enzymes, glucose and transporter proteins in the cell membrane, and ions and pore-type channels
A cell that responds to a chemical messenger secreted by another cell is called the ____________.
target cell
The term simple diffusion can be used to describe __________, from areas of high concentration to areas of lower concentration.
the movement of oxygen molecules across the cell membrane and the movement of oxygen molecules in air
As the solute concentration of a solution increases, __________.
the water concentration decreases and the osmotic pressure increases
The term used to describe the minimum stimulus to trigger a response in a feedback loop is __________.
threshold
