Biology 1407 Test #2 Ch. 42,43,44

Which secretion is not a barrier that prevents pathogens from entering the body?

Antigens

Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____. macrophages ... B cells and T cells B cells ... macrophages T cells ... B cells B cells ... plasma cells and memory cells helper T cells ... plasma cells

B cells, plasma cells and memory cells

Which of the following occurs when body temperature decreases below normal body temperature

Blood vessels in the skin constrict to help prevent heat loss.

Each person makes more than 1 million different B cell antigen receptors and more than 10 million different T cell antigen receptors. How is such diversity in antigen receptors generated?

By combining variable elements, the immune system assembles many different receptors from a much smaller collection of parts

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers

Fluffing creates a pocket of air near the bird that acts as insulation

_____ interact with the antigen-class II MHC complex presented by macrophages. Bacterial cells B cells Epithelial cells Cytotoxic T cells Helper T cells

Helper T cells

Which statement regarding the mammalian heart is correct?

In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs.

Which statement about the gas exchange system in fish is correct?

It enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries.

How do cells involved in the innate immune response detect the presence of pathogens

Leukocytes recognize unique molecules on pathogens

Tissues are immunogically "typed" before an organ transplant to make sure that the donor and recipient match as closely as possible in their

MHC (major histocompatibility complex) proteins

Which of the following cells can engulf a pathogen

Macrophages

Which of these cells is responsible for the rapidity of the secondary immune response? memory cells cytotoxic T cells macrophages plasma cells cytokines

Memory Cells

Which of the following events would you predict as carbon dioxide is released from your muscles into the surrounding capillary bed?

Oxygen delivery to muscle is increased when more carbon dioxide is produced by the muscle.

Which of the following events occurs first when a wound that breaks the skin has occurred

Platelets release proteins that form clots and decrease bleeding.

Cellular respiration

Produces CO2 and ATP

Which statement about human blood vessels is correct

Pulmonary veins carry oxygen-rich blood to the heart.

fishes

The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the _____.

Which statement about oxygen in fish gills is correct?

The partial pressure of oxygen in blood increases as it flows through gill capillaries.

What is the first thing that happens when body temperature increases above normal body temperature

The thermostat in the hypothalamus activates cooling mechanisms

The partial pressure of oxygen at a particular point in the bloodstream is 100 mm Hg. Under what circumstance will there be a net diffusion of oxygen from the water into the bloodstream at this location?

There will be a net diffusion of oxygen from the water into the bloodstream only if the partial pressure of oxygen in the water is greater than 100 mm Hg.

Which of the following statements best describes the role of mast cells in the inflammatory response?

They release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the bloodstream.

The site of inflammation may become swollen due to the increased numbers of cells and fluids at the site and painful due to signals from pain receptors.

True

You and a friend were in line for a movie when you noticed the woman in front of you sneezing and coughing. Both of you were equally exposed to the woman's virus, but over the next few days, only your friend acquired flu-like symptoms and was ill for almost a week before recovering. Which one of the following is a logical explanation for this?

You had an adaptive immunity to that virus.

You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?

You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

Stroke occurs when

a blood clot enters the cerebral circulation, blocking an artery and causing the death of brain tissue

In a physiological system operating with positive feedback,

a change in a variable will amplify rather than reverse the change

Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have

a closed circulatory system

Which of the following is the best definition of autoimmune disease?

a condition in which self molecules are treated as nonself (loss of self-tolerance)

By picking up hydrogen ions, hemoglobin prevents the blood from becoming too

acidic

A normal event in the process of blood clotting is the

activation of prothrombin to thrombin

Clonal selection is an explanation for how

an antigen can provoke production of high amounts of specific antibodies

A patient who has a high level of mast cell activity, dilation of blood vessels, and acute drop in blood pressure is likely suffering from

anaphylactic shock immediately following exposure to an allergen

Most land-dwelling invertebrates and all of the amphibians

are ectothermic organisms with variable body temperatures

Most carbon dioxide is carried from the body tissues to the lungs

as bicarbonate ions (HCO3 -)

Select the pathway that would lead to the activation of cytotoxic T cells.

body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface

The smallest airway through which inspired air passes before gas exchange occurs in the mammalian lungs is the

bronchiole

Which of the following best describes an artery?

carry blood away from the heart

What is the function of reverse transcriptase?

catalyzing the formation of DNA from a RNA template

In the blood most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues

combined with hemoglobin

he countercurrent arrangement of blood vessels is an adaptation that allows the goose to

conserve heat in its core when the goose is swimming in cold water

Most of the carbon dioxide produced by humans is

converted to bicarbonate ions

T cells of the immune system include

cytotoxic and helper cells

During aerobic exercise, the partial pressure of oxygen in muscle cells will ________, thus the rate of diffusion of oxygen into the muscle tissue from the blood will ________.

decrease; increase

Damage to the sinoatrial node in humans would

disrupt the rate and timing of cardiac muscle contractions

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The __________ would have the highest total annual energy expenditure, and the __________ would have the highest energy expenditure per unit mass.

elephant; mouse

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in

environments with variable and limited food sources

The panting responses observed in overheated birds and mammals dissipate excess heat by

evaporation

To maintain homeostasis, freshwater fish must

excrete large quantities of water

The leukocytes of the innate immune system are B cells, macrophages, and neutrophils.

false

A decrease of blood pH from 7.4 to 7.2 causes hemoglobin to

give up more of its oxygen molecules

In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid?

grasshoppers

B cells interacting with helper T cells are stimulated to differentiate when _____.

helper T cells release cytokines

The body's automatic tendency to maintain a constant and optimal internal environment is termed as

homeostasis

What is the source of a viral envelope?

host cell membrane

The temperature-regulating center of vertebrate animals is located in the

hypothalamus

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

increased activity of the immune system

From the capillaries of the abdominal organs and hind limbs, blood flows to the

inferior vena cava

A boy falls while riding his bike. A scrape on his hand almost immediately begins to bleed and becomes red, warm, and swollen. What response is occurring?

inflammatory response

A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to

interact with a class II MHC-antigen complex

In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm

invests little energy in temperature regulation

An antigen

is a foreign molecule that evokes a specific response by a lymphocyte

Macrophages are

large, phagocytic cells that can leave the circulation and enter the tissues of the body

Voice sounds are produced by the

larynx

From the pulmonary veins, blood flows to the

left atrium

Compared with a smaller cell, a larger cell of the same shape has

less surface area per unit of volume.

Blood cells that function to fight infection are called

leukocytes

Which of these cells is a phagocytic leukocyte that can engulf a foreign bacterium? cytotoxic T cell helper T cell plasma cell macrophage B cell

macrophage

The cells and signaling molecules involved in the initial stages of the inflammatory response are

mast cells and histamines

The primary functions of the _____ are to warm, filter, and humidify air.

nasal cavity

Atrial systole

occurs at the same time as ventricular diastole

What type of immunity is associated with breast feeding

passive immunity

The role of cytotoxic T cells is the secretion of _____, which plays a role in the _____ immune response. antibodies ... antibody-mediated interleukin-2 ... humoral perforin ... cell-mediated antibodies ... humoral perforin ... humoral

perforin, cell-mediated

B cells that have been stimulated by interleukin-2 develop into _____. macrophages antigens plasma cells cytotoxic T cells helper T cells

plasma cells

Which of these cells produce and secrete antibodies? bacterial cells helper T cells macrophages plasma cells cytotoxic T cells

plasma cells

Alternative RNA splicing

produces multiple proteins from a single coding gene.

Double-stranded viral DNA is incorporated into a host cell as a

provirus

Blood returns to the heart via the

pulmonary veins

To prepare flight muscles for use on a cool morning, hawkmoths

rapidly contract and relax these muscles to generate metabolic warmth

What would be the consequence if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, then out the mouth? This reversal of water flow would

reduce efficiency of gas exchange

A countercurrent heat exchanger enables an animal to

reduce the loss of body heat to the environment

From the superior vena cava, blood flows to the

right atrium

A bacterium or other particle taken up by phagocytosis is

routed to lysosomes for degradation

The osmoregulatory process called secretion refers to the

selective elimination of excess ions and toxins from body fluids

The genetic material of HIV consists of _____.

single-stranded RNA

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

systole of the left ventricle

When antibodies bind antigens, the clumping of antigens results from

the antibody having at least two binding regions

Circulatory systems compensate for

the slow rate at which diffusion occurs over large distances

Which of the following is the correct sequence of blood flow in birds and mammals

vena cava → right atrium → right ventricle → pulmonary artery

An advantage of gas exchange in fresh water, compared with gas exchange in air, is that

water loss through evaporation across the respiratory surface can be minimized