Organisms with a circulating body fluid that is distinct from the
fluid that directly surrounds the body's cells are likely to have
A) an open circulatory system.
B) a closed circulatory system.
C) a gastrovascular cavity.
D) branched tracheae.
To adjust blood pressure independently in the capillaries of the
gas-exchange surface and in the capillaries of the general body
circulation, an organism would need a(n)
A) open circulatory system.
C) lymphatic system.
D) two-chambered heart.
E) four-chambered heart.
Which of the following pairs of mammalian blood vessels has blood
that is the least similar in its gas content?
A) the pulmonary vein and the jugular vein
B) the veins from the right and left legs
C) the pulmonary artery and the vena cava
D) the pulmonary vein and the aorta
E) the inferior vena cava and the superior vena cava
After several weeks of exercise, a human athlete's resting heart rate
is typically lower than before because
A) the body needs less oxygen than before.
B) the body temperature has increased.
C) the stroke volume has increased.
D) the cardiac output has decreased.
E) the body produces less carbon dioxide than before.
Which of the following is the correct sequence of blood flow in
reptiles and mammals?
A) left ventricle → aorta → lungs → systemic circulation
B) right ventricle → pulmonary vein → pulmocutaneous circulation
C) pulmonary vein → left atrium → left ventricle → pulmonary circuit
D) vena cava → right atrium → right ventricle → pulmonary circuit
E) right atrium → pulmonary artery → left atrium → ventricle
Damage to the sinoatrial node in humans
A) is a major contributor to heart attacks.
B) would block conductance between the bundle branches and the Purkinje fibers.
C) would have a negative effect on peripheral resistance.
D) would disrupt the rate and timing of cardiac muscle contractions.
E) would have a direct effect on blood pressure monitors in the aorta.
The semilunar valves of the mammalian heart
A) are the route by which blood flows from the atria to the ventricles.
B) are found only on the right side of the heart.
C) are the attachment site where the pulmonary veins empty into the heart.
D) prevent backflow of blood in the aorta and pulmonary arteries.
E) are at the places where the anterior and posterior venae cavae empty into the heart.
The set of blood vessels with the slowest velocity of blood flow is
A) the arteries.
B) the arterioles.
C) the metarterioles.
D) the capillaries.
E) the veins.
The set of blood vessels with the lowest blood pressure driving flow is
A) the arteries.
B) the arterioles.
C) the metarterioles.
D) the capillaries.
E) the veins.
Dissolved proteins in human plasma include which of the following?
A) I only
B) II only
C) I and III only
D) II and III only
E) I, II, and III
Small swollen areas in the neck, groin, and axillary region are
A) increased activity of the immune system.
B) a broken limb.
C) blood sugar that is abnormally high.
E) sodium depletion.
Sponges, cnidarians, and flatworms lack a specialized gas exchange
A) they are too large for a circulatory system to operate well.
B) they live without need for oxygen.
C) they do not produce carbon dioxide.
D) countercurrent exchange mechanisms cannot function well in their living conditions.
E) nearly all of their cells are in direct contact with the external environment.
The epiglottis of a human covers the glottis when he or she is
In mammals, most gas exchange between the atmosphere and the
pulmonary blood occurs in the
An anthropologist discovers the fossilized heart of an extinct
animal. The evidence indicates that the organism's heart was large,
well-formed, and had four chambers, with no connection between the
right and left sides. A reasonable conclusion supported by these
observations is that the
A) animal had evolved from birds.
B) animal was endothermic and had a high metabolic rate.
C) animal was most closely related to alligators and crocodiles.
D) animal was likely an invertebrate animal.
E) species had little to no need to regulate blood pressure.
Pulse is a direct measure of
A) blood pressure.
B) stroke volume.
C) cardiac output.
D) heart rate.
E) breathing rate.
If a molecule of CO₂ released into the blood in your left toe is
exhaled from your nose, it must pass through all of the following
A) the pulmonary vein.
B) an alveolus.
C) the trachea.
D) the right atrium.
E) the right ventricle.
A) is activated immediately upon infection.
B) depends on a newly infected animal's previous exposure to the same pathogen.
C) is based on recognition of antigens that are specific to different pathogens.
D) is found only in vertebrate animals.
E) utilizes highly specific antigen receptors on B cells.
A fruit fly, internally infected by a potentially pathogenic fungus,
is protected by
A) its plasma cells.
B) its immunoglobulins.
C) its antibodies.
D) its antimicrobial peptides.
E) its B cells.
White blood cells engulf bacteria through what process?
The lymphatic fluid
A) is a filtrate of the blood, as is urine.
B) is completely separate from the circulatory system for blood.
C) carries both red and white blood cells.
D) functions in adaptive immunity but not in innate immunity.
E) carries a toxic gas that kills cancerous cells.
An inflammation-causing signal released by mast cells at the site of
an infection is
A) an interferon.
B) lymphatic fluid.
E) sodium ions.
A systemic inflammatory response that is often life-threatening is
A) mild fever.
B) aches and dull pain.
C) septic shock.
D) high blood pressure.
E) increased white blood cell count.
Antihistamine treatment reduces
A) blood vessel dilation.
B) phagocytosis of antigens.
C) MHC presentation by macrophages.
D) the secondary immune response.
E) clonal selection by antigens.
Mammals have Toll-like receptors (TLRs) that can recognize a kind of
macromolecule that is absent from vertebrates but present in/on
certain groups of pathogens, including viral
B) double-stranded DNA.
C) double-stranded RNA.
The receptors on T cells and B cells bind to
C) natural killer cells.
D) double-stranded RNA.
An epitope is
A) part of the interferons that penetrate foreign cells.
B) a protein protruding from the surface of B cells.
C) two structurally similar antibodies dissolved in the blood plasma.
D) that part of an antigen that actually binds to an antigen receptor.
E) a mirror image of an antigen.
A newborn who is accidentally given a drug that destroys the thymus
would most likely
A) lack class I MHC molecules on cell surfaces.
B) lack humoral immunity.
C) be unable to genetically rearrange antigen receptors.
D) be unable to differentiate and mature T cells.
E) have a reduced number of B cells and be unable to form antibodies.
The MHC is important in a T cell's ability to
A) distinguish self from nonself.
B) recognize specific parasitic pathogens.
C) identify specific bacterial pathogens.
D) identify specific viruses.
E) recognize differences among types of cancer.
An immunoglobulin (Ig) molecule, of whatever class, with regions
symbolized as C or V, H or L, has a light chain made up of
A) one C region and one V region.
B) three C regions and one V region.
C) one H region and one L region.
D) three H regions and one L region.
E) two C regions and two V regions.
An epitope associates with which part of an antigen receptor or
A) the disulfide bridge
B) the heavy-chain constant regions only
C) variable regions of a heavy chain and light chain combined
D) the light-chain constant regions only
E) the tail
This type of immunity is present only when a newborn infant is being
fed by actively nursing on its mother and ends when nursing ends.
A) innate immunity
B) active immunity
C) passive immunity
D) cell-mediated immunity
E) adaptive immunity
The cell-mediated immunity that destroys virally infected cells
A) cytotoxic T cells.
B) natural killer cells.
C) helper T cells.
E) B cells.
B cells interacting with helper T cells are stimulated to
A) B cells produce IgE antibodies.
B) B cells release cytokines.
C) helper T cells present the class II MHC molecule-antigen complex on their surface.
D) helper T cells differentiate into cytotoxic T cells.
E) helper T cells release cytokines.
In the human disease known as lupus, there is an immune reaction
against a patient's own DNA from broken or dying cells, which
categorizes lupus as
A) an allergy.
B) an immunodeficiency.
C) an autoimmune disease.
D) an antigenic variation.
E) a cancer.
Vaccination increases the number of
A) different receptors that recognize a pathogen.
B) lymphocytes with receptors that can bind to the pathogen.
C) epitopes that the immune system can recognize.
D) macrophages specific for a pathogen.
E) MHC molecules that can present an antigen.
In which of the following would there be the greatest need for
A) an animal connective tissue cell bathed in isotonic body fluid
B) cells of a tidepool animal such as an anemone
C) a red blood cell surrounded by plasma
D) a lymphocyte before it has been taken back into lymph fluid
E) a plant being grown hydroponically (in a watery mixture of designated nutrients)
Which of the following membrane activities require energy from ATP
A) facilitated diffusion of chloride ions across the membrane through a chloride channel
B) movement of water into a cell
C) Na⁺ ions moving out of a mammalian cell bathed in physiological saline
D) movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell
E) movement of carbon dioxide out of a paramecium
The body fluids of an osmoconformer would be ________ with its
A) hyperosmotic; freshwater
B) isotonic; freshwater
C) hyperosmotic; saltwater
D) isoosmotic; saltwater
E) hypoosmotic; saltwater
A) insoluble in water.
B) more toxic to human cells than ammonia.
C) the primary nitrogenous waste product of humans.
D) the primary nitrogenous waste product of most birds.
E) the primary nitrogenous waste product of most aquatic invertebrates.
The primary nitrogenous waste excreted by birds is
E) uric acid.
The osmoregulatory process called secretion refers to the
A) formation of filtrate at an excretory structure.
B) reabsorption of nutrients from a filtrate.
C) selective elimination of excess ions and toxins from body fluids.
D) formation of an osmotic gradient along an excretory structure.
E) expulsion of urine from the body.
Excretory organs known as Malpighian tubules are present in
E) sea stars.
Which of the following statements is correct about diffusion?
A) It is very rapid over long distances.
B) It requires an expenditure of energy by the cell.
C) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
D) It is an active process in which molecules move from a region of lower concentration to one of higher concentration.
E) It requires integral proteins in the cell membrane.
Low selectivity of solute movement is a characteristic of
A) salt pumping to control osmolarity.
B) H+ pumping to control pH.
C) reabsorption mechanisms along the proximal tubule.
D) filtration from the glomerular capillaries.
E) secretion along the distal tubule.
A primary reason that the kidneys have one of the highest metabolic
rates of all body organs is that
A) it stores the body's excess fats.
B) it has membranes of varying permeability to water.
C) it operates an extensive set of active-transport ion pumps.
D) it is the body's only means of shedding excess nutrients.
E) it has an abundance of myogenic smooth muscle.
Juxtamedullary nephrons can concentrate salt effectively in the renal
medulla because of their long
A) loops of Henle.
B) distal convoluted tubules.
C) Bowman's capsules.
D) proximal convoluted tubules.
The high osmolarity of the renal medulla is maintained by all of the
A) diffusion of salt from the thin segment of the ascending limb of the loop of Henle.
B) active transport of salt from the upper region of the ascending limb.
C) the spatial arrangement of juxtamedullary nephrons.
D) diffusion of urea from the collecting duct.
E) diffusion of salt from the descending limb of the loop of Henle.
Increased ADH secretion is likely after
A) drinking lots of pure water.
B) sweating-induced dehydration increases plasma osmolarity.
C) ingestion of ethanol (drinking alcoholic drinks).
D) eating a small sugary snack.
E) blood pressure is abnormally high.
After drinking alcoholic beverages, increased urine excretion is the
A) increased aldosterone production.
B) increased blood pressure.
C) inhibited secretion of antidiuretic hormone (ADH).
D) increased reabsorption of water in the proximal tubule.
E) the osmoregulator cells of the brain increasing their activity.
A) are produced by endocrine glands.
B) are lipid-soluble molecules.
C) are carried to target cells in the blood.
D) are protein molecules.
E) elicit the same biological response from all of their target cells.
In a positive-feedback system where hormone A alters the amount of
A) an increase in A always produces an increase in X.
B) an increase in X always produces a decrease in A.
C) a decrease in A always produces an increase in X.
D) a decrease in X always causes a decrease in A.
E) it is impossible to predict how A and X affect each other.
Testosterone is an example of a chemical signal that affects the very
cells that synthesize it, the neighboring cells in the testis, along
with distant cells outside the gonads. Thus, testosterone is an
A) an autocrine signal.
B) a paracrine signal.
C) an endocrine signal.
D) both an autocrine signal and a paracrine signal.
E) an autocrine signal, a paracrine signal, and an endocrine signal.
A cell with membrane-bound proteins that selectively bind a specific
hormone is called that hormone's
A) secretory cell.
B) plasma cell.
C) endocrine cell.
D) target cell.
E) regulatory cell.
Different body cells can respond differently to the same peptide
A) different target cells have different sets of genes.
B) each cell converts that hormone to a different metabolite.
C) a target cell's response is determined by the components of its signal transduction pathways.
D) the circulatory system regulates responses to hormones by routing the hormones to specific targets.
E) the hormone is chemically altered in different ways as it travels through the circulatory system.
Insect hormones and their receptors
A) act independently of each other.
B) are a focus in pest-control research.
C) utilize cell-surface receptors only.
D) are active independently of environmental cues.
E) are not relevant to the study of steroid hormones.
Suppose that substance X is secreted by one cell, travels via
interstitial fluid to a neighboring cell, and produces an effect on
that cell. All of the following terms could describe this substance
A) paracrine signal.
E) growth factor.
Steroid and peptide hormones typically have in common
A) the building blocks from which they are synthesized.
B) their solubility in cell membranes.
C) their requirement for travel through the bloodstream.
D) the location of their receptors.
E) their reliance on signal transduction in the cell.
If a person loses a large amount of water in a short period of time,
he or she may die from dehydration. ADH can help reduce water loss
through its interaction with its target cells in the
A) anterior pituitary.
B) posterior pituitary.
C) adrenal gland.
Iodine is added to table salt to help prevent deficiencies of an
essential mineral needed for the proper function of the
A) parathyroid glands.
B) adrenal glands.
C) thyroid glands.
D) the endocrine pancreas.
E) the exocrine pancreas.
After eating a carbohydrate-rich meal, the mammalian pancreas
increases its secretion of
Analysis of a blood sample from a fasting individual who had not
eaten for 24 hours would be expected to reveal high levels of
The main target organs for tropic hormones are
B) blood vessels.
C) endocrine glands.
A) functions only as an endocrine target, by having lots of receptors on its cells.
B) functions only in neuronal transmission.
C) does not have any hormone receptors on its cells.
D) secretes tropic hormones that act directly on the gonads.
E) includes neurosecretory cells that terminate in the posterior pituitary.
Winter hibernation and spring reproduction in bears are cued by
seasonal changes in the secretion of
A) melatonin from the pineal gland.
B) melatonin from the hypothalamus.
C) thyroxine from the anterior pituitary gland.
D) acetylcholine from the pineal gland.
E) thyroid-stimulating hormone from the posterior pituitary gland.
The increased contraction of the human uterus during labor and
delivery is at least partially due to the actions of
E) growth hormone.
Abnormally reduced somatic growth (dwarfism) can be a consequence of
decreased hormone secretion from the
C) adrenal gland.
D) posterior pituitary gland.
E) anterior pituitary gland.
The autonomic nervous system includes an endocrine gland known as the
B) adrenal medulla.
C) adrenal cortex.
Estradiol is an example of
A) an androgen.
B) an estrogen.
C) a progestin.
D) a catecholamine.
E) a glucocorticoid.
An example of a properly functioning homeostatic control system is seen when
A) a blood cell shrinks when placed in a solution of salt and water
B) the core body temperature of a runner ruses gradually from 37C to 45C
C) the kidneys excrete salt into the urine when dietary salt levels rise
D) the level of glucose in the blood is abnormally high whether or not a meal has been eaten