The meshwork that forms the fabric of a blood clot is

fibrin.

A normal event in the process of blood clotting is the

activation of prothrombin to thrombin.

The material present in arterioles that is not present in capillaries is

circular smooth muscle cells that can alter the size of the arterioles.

The production of red blood cells is stimulated by

erythropoietin.

The set of blood vessels with the lowest blood pressure driving flow is

the veins.

The set of blood vessels with the slowest velocity of blood flow is

the capillaries.

At an atmospheric pressure of 870 mm Hg of 21% oxygen, the partial pressure of oxygen is

182 mm Hg.

Because adult lampreys attach onto the surface of large fish for long periods of time to feed on body fluids, they can accomplish nutritional balance without need for a

stomach.

Carbon dioxide levels in the blood and cerebrospinal fluid affect its pH. This enables the organism to sense a disturbance in gas levels as

the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing.

A person with a tidal volume of 450 mL, a vital capacity of 4,000 mL, and a residual volume of 1,000 mL would have a potential total lung capacity of

5,000 mL.

An increase from pH 7.2 to pH 7.4 around hemoglobin causes

an increase in the affinity of hemoglobin to bind oxygen molecules.

Glandular secretions that are released initially as inactive precursors of digestive enzymes are the

protein-digesting enzymes.

The diagnosis of hypertension in adults is based on the

blood pressure being greater than 140 mm Hg systolic and/or >90 diastolic.

A group of animals among which a relatively long cecum is likely to be found is the

herbivores.

In mammals, most gas exchange between the atmosphere and the pulmonary blood occurs in the

alveoli.

Which of the following cells are involved in cell-mediated immunity and also respond to class I MHC molecule-antigen complexes?

cytotoxic T cells

The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of

protonephridia.

The receptors on T cells and B cells bind to

antigens.

Antibodies of the different classes IgM, IgG, IgA, IgD, and IgE differ from each other

in their heavy-chain structure.

The switch of one B cell from producing one class of antibody to another antibody class that is responsive to the same antigen is due to

the rearrangement of immunoglobulin heavy-chain C region DNA.

In active immunity, but not passive immunity, there is

the requirement for direct exposure to a living or simulated pathogen.

Freshwater flatworms form a urine that is typically

of low solute concentration and of high volume, matching their normal fluid uptake.

Histamines trigger dilation of nearby blood vessels as well as an increase in their permeability, producing

redness, heat, and swelling.

After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as

renin.

When antibodies bind antigens, the clumping of antigens results from

the multivalence of the antibody having at least two binding regions.

Among mammals, it is generally true that

the epiglottis prevents swallowed food from entering the trachea.

Which of the following develops the greatest pressure on the blood in the mammalian aorta?

systole of the left ventricle

Small swollen areas in the neck, groin, and axillary region are associated with

increased activity of the immune system.

At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21% oxygen, then the partial pressure of oxygen at this altitude is

80 mm Hg.

A portal system is

a vessel or vessels connecting two capillary beds

If you were to jog 1 km a few hours after lunch, which stored fuel would you probably tap?

muscle and liver glycogen

Because adult lampreys attach onto the surface of large fish for long periods of time to feed on body fluids, they can accomplish nutritional balance without need for a

stomach

The blood pressure is lowest in the

venae cavae.

Which of the following organs is incorrectly paired with its function?

large intestine & bile production

The hemocyanin of arthropods and molluscs differ from the hemoglobin of mammals in that

hemocyanin has protein coupled to copper rather than iron.

Juxtamedullary nephrons can concentrate salt effectively in the renal medulla because of their long

loops of Henle

Which of the following statements is not true?

A lymphocyte has receptors for multiple different antigens.

After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as

renin

The MHC is important in a T cell's ability to

distinguish self from nonself.

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.

passive immunity

An immune response to a tissue graft will differ from an immune response to a bacterium because

MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules.

After a long and cold winter, Jim was excited to start exploring the woods behind his new home. His first adventure included exposure to poison ivy without any reaction. A month later, though, a second walk through the woods was not so great, since two days later Jim had a terrible rash that lasted for weeks. The fact that the rash took two days to develop indicates that this immune response was an example of

cell-mediated immunity

An inflammation-causing signal released by mast cells at the site of an infection is

histamine

A newborn who is accidentally given a drug that destroys the thymus would most likely

be unable to differentiate and mature T cells

Cave art by early humans recognized the existence of the major signs of inflammation. The most inclusive set of symptoms of inflammation that might appear in such early human art is

swelling, heat, redness, and pain

Gas exchange is more difficult for aquatic animals with gills than for terrestrial animals with lungs because

water contains much less O2 than air per unit volume.

Digestive secretions with a pH of 2 are characteristic of the

stomach.

Mouse mutations can affect an animal's appetite and eating habits. The ob
gene codes for a satiety factor, the hormone leptin. The db gene product, the leptin receptor, is required to respond to the satiety factor. Leptin is a product of adipose cells. Therefore, a very obese mouse would be expected to have

mutation of ob or db.

After surgical removal of an infected gallbladder, a person must be especially careful to restrict dietary intake of

fat.

In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?

frogs

A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery in the arm to the left ventricle, this red blood cell must pass through

two capillary beds.

Circulatory systems in molluscs

are open in species of small-sized molluscs and are closed in species of large-sized molluscs.

Historically inaccurate diagnosis of acid reflux disorders and gastric ulcers has been improved by

the diagnosis and treatment of H. pylori infection.

The hormone that stimulates the production of red blood cells, and the organ where this hormone is synthesized, are

erythropoietin and kidney, respectively.

The circulatory system of bony fishes, rays, and sharks is similar to

the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber.

Which of the following is not a major activity of the stomach?

nutrient absorption

An oil-water mixture works as an insecticidal spray against mosquitoes and other insects because it

blocks the openings into the tracheal system.

Complex nutrients are digested and then absorbed into the lymph or bloodstream as

monomers.

Hemoglobin and hemocyanin

both transport oxygen.

Among these choices, the biggest set that includes only those "cells" that lack nuclei is

platelets and erythrocytes.

Phenylketonuria (PKU) is a hereditary condition in which infants and young children who ingest the amino acid phenylalanine risk serious neurological damage. However, the risk of damage can be substantially reduced by the severe restriction of phenylalanine in the diet. Which of the following is the nutritional concept that forms the basis for this preventive treatment?

essential nutrients

The bile salts

emulsify fats in the duodenum.

Air-breathing insects carry out gas exchange

across the membranes of their cells.

The semilunar valves of the mammalian heart

prevent backflow of blood in the aorta and pulmonary arteries.

Of the following choices, impairment of a mammal's breathing cycle is most likely following neural damage in

the medulla oblongata and the pons.

A group of students was designing an experiment to test the effect of smoking on grass frogs. They hypothesized that keeping the frogs in a smoke-filled environment for defined periods would result in the animals developing lung cancer. However, when they searched for previously published information to shore up their hypothesis, they discovered they were quite wrong in their original assessment. Even though they were never going to go ahead with their experiment (so as not to harm frogs needlessly), they knew that a more likely outcome of putting carcinogens in the air would be the development of

skin cancer.

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by

tolerating high urea concentrations that balance internal salt concentrations to seawater osmolarity.

The fluid with the highest osmolarity is

seawater in a tidal pool.

Yearly vaccination of humans for influenza viruses is necessary because

rapid mutation in flu viruses alters the surface proteins in infected host cells.

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

double-stranded RNA.

Ancient peoples sought to identify the indicators of inflammation because

the presence of these signs suggests that healing was taking place; otherwise, the patient would likely die.

Low selectivity of solute movement is a characteristic of

filtration from the glomerular capillaries.

A person with alkalosis will likely excrete urine that has abnormally high levels of

sodium ions.

An otherwise healthy student in your class is infected with EBV, the virus that causes infectious mononucleosis. The same student had already been infected when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. This time, though infected, she does not get sick. The EBV antigen fragments will be presented by the virus-infected cells along with

class I MHC molecules.