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

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

PKU (phenylketonuria) 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 in the nutritional concept that forms the basis for this preventative treatment?

Essential Nutrients

Hypoglycemia, or low levels of glucose in the blood of a healthy human, is 'corrected" by a(n)

Increase in secretion of glucagon

In a cold and yet survivable environment, an ectoderm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because ectoderms

invest little energy in temperature regulation

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

Fat

Coutercurrent exchange in the fish gill helps to maximize

diffusion

The bile salts function in fat digestion by?

dispersing big droplets of fats to small droplets

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

Fishes

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

homeostasis

Human red blood cells 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 to the thumb and the back to the left ventricle, this red blood cell must pass through?

two capillary beds

An example of a properly functioning homeostatic control system is seen when?

The kidneys excrete salt into the urine when dietary salt levels rise

Without functioning parietal cells an individual would

not be able to initiate protein digestion in the stomach

The most important chemical stimuli leading to increased rate and depth of breathing is?

concentration of CO2 in the blood

Which common event most closely resembles negative feedback?

The furnace turns off when the temperature in the room reaches the set point

After ingestion, the first type of macromolecule to be enzymatically attacked in the human digestive system is?

Carbohydrates

In the circulatory system of humans, how is most of the carbon dioxide transported?

Bicarbonate ions in the plasma

Stomach acid

activates pepsinogen into pepsin

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

Large intestine and bile production

An example of a connective tissue is the

Blood

An advantage of a complete digestive system over a gastrovascular cavity is that the complete system

allows specialized functions in specialized regions

An increase in pH 7.2 to pH 7.4 around hemoglobin causes

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

Increased levels of glucose levels in blood after a meal may trigger

insulin release from the pancreas

Use the figure above to answer this question. When does contraction of the atria begin?

immediately after the P-wave

Digestive secretions with a pH of 2 are characteristic of the?

stomach

Air rushes into the lungs of humans during inhalation because

the rib muscles and diaphragm are contracted, increasing the lung volume

Three types of cells which are present in the gastric glands are responsible for some secretion of gastric juice. ____ cells secrete pepsinogen (an inactive form of digestive enzyme pepsin). _____ cells lubricate and protect the cells lining in the stomach. ____ cells secrete HCl

chief, mucus, parietal

Which of the following explains the reason that the velocity of blood blow is the lowest in capillaries?

The total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries of any other part of the circulatory system

The bile salts

emulsify fats in the duodenum

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having

A thick mucous secretion and active mitosis in epithelial cells

Why is gas exchange more difficult for aquatic animals with gild than for terrestrial animals with lungs?

water contains much less O2 than air per unit volume

A rabbit taken from a meadow near sea level and moved to a meadow high on a mountainside would have some trouble breathing. Why?

the partial pressure of O2 in the air at high elevations is lower than at sea level

Cyanide poisons mitochondria by blocking the final step in the electron transport chain. Human red blood cells placed in an isotonic solution containing cyanide are likely to?

be unaffected

The Bohr shift on the oxygen-hemoglobin dissociation curve (see figure 1 below) is produced by changes in?

pH

which of the following organisms breathe through tracheae?

insects

Agents that help emulsify fats are produced by?

9

What structures are involved in the digestion of carbohydrates?

1 and 4

the thin horizontal arrows in the figure show that?

The warmer arterial blood transfers hear to the cooler venous blood

What percentage of individuals in the study group had an LDL level below 100 mg/dL?

about 58%

what percentage of individuals in the control group had an LDL level below 100 mg/dL?

17%

Based on these two histograms what conclusion can you draw?

On average, individuals with an inactivating mutation in the PCSK9 gene have lower plasma LDL levels than wild type individuals

How would you compare the risk of cardiovascular disease between the study group and the control group?

the study group has a lower risk than the control group

what is the best explanation for the fact that the two histograms overlap as much as they do?

many factors in addition to PCSK9 enzyme activity affect plasma LDL levels

Now consider two individuals with a plasma LDL level of 160 Mg/dL, one from the study group and one from the control group. What do you predict regarding their relative risk for cardiovascular disease?

the risk is equal because their LDL levels are the same

The direction of blood flow in the fish gills is opposite the direction of eater flow past the gills. Which of the following should be expected if the structural relationship represents a countercurrent exchange mechanism for O2?

A net movement of oxygen from water into blood occurs along the entire distance where blood and water are in close contact

What percentage of the mouse's energy budget goes to basal metabolism?

about 25%

without considering the sizes of wedges, how do three pie charts differ in which function they include?

unlike the penguin and the mouse charts the python chart included growth but does not include thermoregulation