Biology 126 Exam One

Select the correct statement about osmoregulation. A) All osmoconformers are marine animals. B) All marine invertebrates are stenohaline. C) The less the gradient between an animal's internal osmolarity and its external osmolarity (that of its surroundings), the higher the cost of osmoregulation.

A) All osmoconformers are marine animals.

Why does the velocity of blood slow greatly as blood flows from arterioles into capillaries? A) Because capillary beds have a total cross-sectional area much greater than the total cross-sectional area of the arterioles. B) Because the narrow capillaries offer great resistance to blood flow. C) Because capillary beds are the site of nutrient and oxygen delivery to tissues.

A) Because capillary beds have a total cross-sectional area much greater than the total cross-sectional area of the arterioles. Because the cross-sectional area is much greater in capillary beds than in the arteries or any other part of the circulatory system, there is a dramatic decrease in velocity from the arteries to the capillaries. Blood travels 500 times slower in the capillaries (about 0.1 cm/sec) than in the aorta (about 48 cm/sec). Read about blood flow velocity.

What is the driving force for the filtration of blood by the renal corpuscle? A) Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule. B) The presence of microvilli. C) The presence of large pores in the glomerular capillaries and filtration slits. D) The diffusion of small solutes such as urea down a concentration gradient.

A) Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule.

Choose the correct statement from the list below. A) Proteins that are consumed in the diet are absorbed as individual amino acids following digestion. B) Protein digestion begins in the small intestine with the activation of trypsinogen to trypsin C) Mechanical digestion of proteins is more important than chemical digestion. D) The stomach has a high pH which allows for the activation of digestive enzymes.

A) Proteins that are consumed in the diet are absorbed as individual amino acids following digestion.

Which term describes a steady state in which the internal conditions of an organism are kept within a narrow range without regard to the external conditions? A) Regulatory homeostasis. B) Conformational homeostasis. C) Thermoregulation. D) Negative feedback.

A) Regulatory homeostasis.

Which of the following represents the correct sequence of flow through the nephron? A) Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct B) Renal corpuscle > distal tubule > proximal tubule > loop of Henle > collecting duct C) Renal corpuscle > loop of Henle > collecting duct > proximal tubule > distal tubule D) Distal tubule > loop of Henle > collecting duct > renal corpuscle > proximal tubule

A) Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct

Select the correct statement describing the osmolarity of mammalian urine. A) The osmolarity of mammalian urine may vary over time. B) The osmolarity of mammalian urine varies little between species C) Mammalian urine is always hyperosmotic to blood.

A) The osmolarity of mammalian urine may vary over time.

The presence of fatty acids and amino acids in the chyme from the stomach triggers the small intestine to secrete a hormone known as _____. A) cholecystokinin, or CCK B) histones C) insulin D) secretin E) thyroxine

A) cholecystokinin, or CCK

What acid is responsible for stomach acidity? A) hydrochloric acid B) carbonic acid C) sulfuric acid D) acetic acid E) sodium hydroxide

A) hydrochloric acid

The hypothalamus A) includes neuronal cells that terminate in the posterior pituitary. B) functions only as an endocrine target, by having lots of receptors on its cells. C) functions only in neuronal transmission. D) secretes tropic hormones that act directly on the gonads. E) does not have any hormone receptors on its cells.

A) includes neuronal cells that terminate in the posterior pituitary.

Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine. A) liver ... gall bladder B) pancreas ... gall bladder C) liver ... pancreas D) gall bladder ... liver E) esophagus ... stomach

A) liver ... gall bladder

Homeostasis is the _____. A) maintenance of a relatively constant and optimal internal environment B) correlation of structure and function C) exchange of materials with the surrounding environment D) cooperation of body parts to form tissues, organs, and systems E) idea that all vertebrates are built in a similar way

A) maintenance of a relatively constant and optimal internal environment *Homeostasis is a dynamic state of optimal conditions, maintained at great expense to the organism.

Secretin stimulates the _____ to secrete _____. A) pancreas ... bicarbonate B) pancreas ... pancreatic enzymes C) small intestine ... disaccharidases D) stomach ... bicarbonate E) liver ... liver enzymes

A) pancreas ... bicarbonate

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe? A) rising CO2 B) rising CO2 and falling O2 C) falling O2 D) falling CO2 E) rising O2

A) rising CO2

Under the influence of _______ more concentrated urine is produced and the body conserves water.

ADH

The epithelium...

Allows the internal environment to remain constant even if the external environment changes.

Arteries transport blood __________ the heart. Renal arteries transport blood __________ kidneys.

Away from ... to the

Which of the following statements describes a negative feedback response? View Available Hint(s) A) The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions. B) After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels. C) The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot. D) A person who loses 3 pounds continues to diet to lose an additional 10 pounds.

B) After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

Which of the following best describes an artery? A) Arteries carry oxygenated blood. B) Arteries carry blood away from the heart. C) Arteries contain valves. D) Arteries have thin walls compared with veins. E) Arteries carry blood away from capillaries.

B) Arteries carry blood away from the heart. Both arteries and veins are defined by the direction relative to the heart in which blood is transported.

Examine the figure of a human nephron. Where and when does osmolarity of the filtrate increase? A) As the filtrate moves through the proximal tubule B) As the filtrate moves down the descending limb of the loop of Henle C) As the filtrate moves up to the cortex in the ascending limb of the loop

B) As the filtrate moves down the descending limb of the loop of Henle

Select the correct statement about capillary beds. A) Capillary beds join arteries and veins. B) Capillary beds are the site of nutrient and oxygen delivery to tissues. C) Capillary beds have a total cross-sectional area much smaller than the total cross-sectional area of major arteries.

B) Capillary beds are the site of nutrient and oxygen delivery to tissues.

Antidiuretic hormone (ADH) makes the _____ permeable to water. A) ascending portion of the loop of Henle B) collecting duct C) Bowman's capsule D) proximal tubule E) descending portion of the loop of Henle

B) Collecting duct

Choose the correct statement from the list below. A) Fat digestion begins in the stomach with the activation of trypsinogen to trypsin. B) Free fatty acid absorption occurs in the small intestine. C) Fats are fully digested after passage through the mouth and stomach. D) Bile salts from the pancreas are essential to the digestion of fats

B) Free fatty acid absorption occurs in the small intestine.

Which statement regarding the mammalian heart is correct? A) Oxygen-loaded blood moves only through the right side of the heart. B) In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs. C) When the right atrium contracts, it forces blood into the left atrium. D) Blood arrives at the heart via the ventricles. E) Blood is pumped from the heart via the atria.

B) In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs. The right heart's contraction moves the blood to the lungs for gas exchange before the blood is delivered to the left atrium.

Which component of a homeostatic system compares sensory information to a target value? A) Sensor. B) Integrator. C) Effector. D) Set point.

B) Integrator.

Which component of a homeostatic system perceives changes in some parameter of the environment? View Available Hint(s) A) Integrator. B) Sensor. C) Effector. D) Set point.

B) Sensor.

Select the correct statement about feedback regulation in endocrine systems. A) A hormone cascade pathway involves the hypothalamus, posterior pituitary, and endocrine gland. B) Some homeostatic control systems rely on pairs of negatively regulated hormone pathways, each counterbalancing the other. C) All hormones are regulated by negative feedback loops.

B) Some homeostatic control systems rely on pairs of negatively regulated hormone pathways, each counterbalancing the other.

In a positive-feedback system where hormone A alters the amount of protein X, A) a decrease in A always produces an increase in X, which results in an increase in A. B) an increase in A always produces an increase in X, which results in an increase in A. C) it is impossible to predict how A and X affect each other. D) an increase in X always produces a decrease in A, which results in a decrease in X. E) a decrease in X always causes a decrease in A, which causes an increase in X.

B) an increase in A always produces an increase in X, which results in an increase in A.

Antidiuretic hormone (ADH) makes the _____ permeable to water. A) ascending portion of the loop of Henle B) collecting duct C) Bowman's capsule D) proximal tubule E) descending portion of the loop of Henle

B) collecting duct

The amount of oxygen bound to hemoglobin _____. A) increases as the pH of tissues decreases B) increases in the presence of high concentrations of oxygen C) decreases in the presence of high concentrations of oxygen D) is called the Bohr shift E) increases with increasing acidity at the tissue level

B) increases in the presence of high concentrations of oxygen High concentrations of oxygen increase the amount of oxygen bound to hemoglobin.

The anterior and posterior lobes of the pituitary differ in that _____. View Available Hint(s) A) the posterior pituitary gland synthesizes oxytocin and antidiuretic hormone whereas the anterior lobe receives all of its hormone products in the blood B) many anterior pituitary hormones regulate other endocrine glands whereas posterior pituitary hormones regulate nonendocrine tissues C) the anterior lobe of the pituitary receives neuronal impulses from brain cells whereas the posterior lobe receives blood-borne hormones D) the anterior lobe of the pituitary is nervous tissue that connects directly to the brain whereas the posterior pituitary is derived from non-neural tissues E) the posterior lobe of the pituitary operates independently of the brain whereas the anterior lobe is directly dependent on brain activity

B) many anterior pituitary hormones regulate other endocrine glands whereas posterior pituitary hormones regulate nonendocrine tissues

Cholecystokinin (CCK) stimulates the _____ to secrete _____. A) pancreas ... bicarbonate B) pancreas ... pancreatic enzymes C) small intestine ... disaccharidases D) stomach ... bicarbonate E) liver ... liver enzymes

B) pancreas ... pancreatic enzymes

Coordinating body functions via chemical signals is accomplished by A) the immune and lymphatic systems. B) the endocrine system. C) the respiratory system. D) the integumentary system. E) the excretory system.

B) the endocrine system.

An example of a properly functioning homeostatic control system is seen when A) the blood pressure increases in response to an increase in blood volume. B) the kidneys excrete salt into the urine when dietary salt levels rise. C) a blood cell shrinks when placed in a solution of salt and water. D) the core body temperature of a runner rises gradually from 37°C to 45°C. E) the level of glucose in the blood is abnormally high whether or not a meal has been eaten.

B) the kidneys excrete salt into the urine when dietary salt levels rise.

Which of these is an example of negative feedback? A) As a blood clot begins to form, the process of its formation gets faster and faster. B) After you eat, glucagon stimulates an increase in blood sugar levels. C) After you eat, insulin stimulates the lowering of blood sugar levels. D) The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin. E) Once labor begins, contractions increase in frequency and intensity.

C) After you eat, insulin stimulates the lowering of blood sugar levels.

Which of the following actions is not a function of the epithelium? View Available Hint(s) A) Creates an internal environment that is different from the external environment. B) Controls the exchange of nutrients between the internal and external environments. C) Allows the internal environment to alter its conditions to match those of the external environment. D) Regulates the excretion of waste.

C) Allows the internal environment to alter its conditions to match those of the external environment.

Which hormone is placed into the correct chemical class? A) Prolactin is a glycoprotein hormone. B) Thyroid-stimulating hormone is an amine hormone. C) Calcitonin is a peptide hormone.

C) Calcitonin is a peptide hormone.

Choose the correct statement from the list below. A) Carbohydrate absorption occurs primarily in the large intestine. B) Carbohydrates are fully digested after passage through the stomach . C) Carbohydrate digestion begins in the mouth with salivary amylase. D) Bile salts from the gall bladder are essential to the digestion of carbohydrates. Submit

C) Carbohydrate digestion begins in the mouth with salivary amylase.

Which of these is the functional unit of a kidney? A) neuron B) villi C) nephron D) alveolus E) osteon

C) Nephron

Select the correct statement about osmolarity. A) If two solutions are separated by a selectively permeable membrane, water flows by osmosis from a hyperosmotic solution to a hypoosmotic one. B) The contents of an animal cell are hyper osmotic. C) Osmolarity measures the moles of solute per liter of solution.

C) Osmolarity measures the moles of solute per liter of solution.

What is the difference between a countercurrent multiplier system, such as the one involving the loop of Henle, and the countercurrent systems that maximize oxygen absorption by fish gills or reduce heat loss in endotherms? A) A countercurrent multiplier system, such as the one involving the loop of Henle, includes a capillary bed. B) A countercurrent multiplier system, such as the one involving the loop of Henle, involves movement of ions rather than movement of oxygen or heat transfer. C) Unlike the other countercurrent systems, a countercurrent multiplier system, such as the one involving the loop of Henle, expends energy in active transport.

C) Unlike the other countercurrent systems, a countercurrent multiplier system, such as the one involving the loop of Henle, expends energy in active transport.

The body's reaction to PTH (parathyroid hormone), a reduction in plasma levels of calcium, can be opposed by A) glucagon. B) thyroxine. C) calcitonin. D) epinephrine. E) growth hormone.

C) calcitonin.

Negative feedback is a method of homeostatic control that _____. A) produces a response by lowering the set point of an organism's metabolism B) increases the speed and rapidity of negative responses to environmental stimuli C) ensures that conditions in an organism do not vary too much above or below their set points D) promotes decreases in metabolic rate rather than increases E) operates independently of most signaling mechanisms

C) ensures that conditions in an organism do not vary too much above or below their set points *In negative feedback circuits, changes in variables trigger control mechanisms that counteract further changes in the same direction.

Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a A) higher PCO2 B) greater bicarbonate concentration C) higher PO2 D) lower osmotic pressure E) lower pH

C) higher PO2

Which of the following would increase the amount of oxygen undergoing net diffusion from the lungs into the blood? A) decreasing the red blood cell count of the blood B) increasing the water vapor content of air in the lungs C) increasing the binding of oxygen to hemoglobin D) decreasing the partial pressure of oxygen in the lung E) increasing the partial pressure of oxygen in the blood

C) increasing the binding of oxygen to hemoglobin

Blood returning to the mammalian heart in a pulmonary vein drains first into the A) right atrium B) right ventricle C) left atrium D) left ventricle E) vena cava

C) left atrium

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that A) nontarget cells convert aldosterone to a hormone to which they do respond. B) it is unable to enter nontarget cells. C) only its target cells contain aldosterone receptors. D) nontarget cells destroy aldosterone before it can produce any effect. E) only its target cells get exposed to aldosterone.

C) only its target cells contain aldosterone receptors.

Starch is a type of _____. A) disaccharide B) nucleotide C) polysaccharide D) fatty acid E) monosaccharide

C) polysaccharide

The counter-regulatory functions of the pancreas refer to the fact that it _____. View Available Hint(s) A) releases acetylcholine when a person is calm, and epinephrine when a person is frightened or exercising B) releases one hormone that increases urine production and another hormone that reduces urine production C) releases one hormone that reduces glucose levels in the blood and another that increases them D) releases one hormone that increases body temperature (fever) and another that decreases body temperature E) releases one hormone that increases heart rate and another that decreases heart rate

C) releases one hormone that reduces glucose levels in the blood and another that increases them

The _____ are the major blood vessels transporting blood to the kidneys A) pulmonary arteries B) glomerulus C) renal arteries D) renal veins E) venae cavae

C) renal arteries

Urine formed by a kidney collects in the _____ before being drained from the kidney by the _____ and transported to the _____ A) urethra ... urinary bladder ... ureter B) renal pelvis ... medulla ... cortex C) renal pelvis ... ureter ...urinary bladder D) renal pelvis ... urethra ... urinary bladder E) ureter ... renal pelvis ... urinary bladder

C) renal pelvis ... ureter ...urinary bladder

Protein digestion begins in the _____. A) mouth B) esophagus C) stomach D) small intestine E) large intestine

C) stomach

Which of the following statements best describes the actions of the hormone ADH on the nephron? A) ADH causes the loop of Henle to increase urea reabsorption under conditions of dehydration. B) ADH causes the distal tubule to increase Na+ reabsorption when Na+ levels in the blood are low. C) ADH causes the proximal tubule to increase glucose reabsorption when the body's energy needs are high. D) ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.

D) ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.

The outer part of the kidney is the _____. A) medulla B) nephron C) lacteal D) cortex E) Bowman's capsule

D) Cortex

Which process is not required for an animal to obtain energy from food? A) Secretion. B) Ingestion. C) Digestion. D) Excretion.

D) Excretion.

Oxytocin and antidiuretic hormone are synthesized in the A) adenohypophysis. B) posterior pituitary. C) adrenal cortex. D) hypothalamus. E) anterior pituitary.

D) Hypothalamus

Which statement about human blood vessels is correct? A) Veins transport blood from the heart to the capillaries. B) Arteries carry oxygenated blood; veins carry oxygen-poor blood. C) The pulmonary artery carries oxygen-rich blood from the lungs. D) Pulmonary veins carry oxygen-rich blood to the heart. E) Arteries carry blood toward the atria of the heart.

D) Pulmonary veins carry oxygen-rich blood to the heart. Following gas exchange in the lungs, the blood moves into the pulmonary veins for its return to the left atrium and then on into the highly muscular left ventricle.

Which regions of the nephron function independently of hormonal control for the most part? A) Distal tubule and collecting duct. B) Renal corpuscle and collecting duct. C) Proximal tubule, loop of Henle, and distal tubule. D) Renal corpuscle, proximal tubule, and loop of Henle.

D) Renal corpuscle, proximal tubule, and loop of Henle

Which structure is not part of the alimentary canal? A) Mouth. B) Esophagus. C) Stomach. D) Salivary glands.

D) Salivary glands.

Which of the following actions acts to warm a homeothermic body? A) Panting. B) Sweating. C) Dilating blood vessels. D) Shivering.

D) Shivering.

Which of the following statements is true? A) Most humans have one kidney, which regulates water and electrolyte balance, removes nitrogenous wastes from the blood, and eliminates the wastes in the urine. B) The kidneys are paired organs that remove nitrogenous wastes from the urine. C) The kidneys regulate water and blood glucose in terrestrial vertebrates. D) The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.

D) The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.

When digested, proteins are broken down into _____. A) glycerol only B) fatty acids only C) monosaccharides D) amino acids E) both glycerol and fatty acids

D) amino acids

Which of these enzymes begins the breakdown of starch? A) bile B) disaccharidases C) lipase D) amylase E) nucleases

D) amylase

Your small intestine can absorb ____ without their being further digested. A) starches B) fats C) proteins D) fructoses E) nucleic acids

D) fructoses

Under the influence of antidiuretic hormone (ADH), _____ is produced. A) urine containing more glucose B) bloody urine C) urine containing a lower concentration of urea D) more concentrated urine E) less concentrated urine

D) more concentrated urine

Under the influence of antidiuretic hormone (ADH), _____ is produced. A) urine containing more glucose B) bloody urine C) urine containing a lower concentration of urea D) more concentrated urine E) less concentrated urine

D) more concentrated urine

The endocrine glands include the A) salivary glands. B) gallbladder. C) sweat glands. D) parathyroid glands. E) sebaceous glands.

D) parathyroid glands.

The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____. A) cholecystokinin, or CCK B) histones C) TSH D) secretin E) pepsin

D) secretin

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 except A) the trachea B) the right atrium C) an alveolus D) the pulmonary vein E) the right ventricle

D) the pulmonary vein

Most types of communication between cells utilize A) the exchange of cytosol between the cells. B) a direct electrical connection between the cells. C) the exchange of DNA between the cells. D) the release of chemical signals by the cell sending the message. E) the movement of the cells.

D) the release of chemical signals by the cell sending the message.

Which of the following respiratory systems is not closely associated with a blood supply? A) the gills of a fish B) the lungs of a vertebrate C) the parapodia of a polychaete worm D) the tracheal system of an insect E) the skin of an earthworm

D) the tracheal system of an insect

What is the main component of gastric juice? A) inactive pepsin B) amylase C) hydrochloric acid D) water E) bile

D) water

_____ is secreted by the _____ and acts to emulsify _____ in the _____. A) Lipase ... small intestine ... fats ... small intestine B) Trypsin ... pancreas ... fats ... small intestine C) Nucleases ... pancreas ... nucleic acids ... stomach D) Amylase ... salivary glands ... starch ... stomach E) Bile ... liver ... fats ... small intestine

E) Bile ... liver ... fats ... small intestine

Different body cells can respond differently to the same peptide hormones because A) the hormone is chemically altered in different ways as it travels through the circulatory system. B) different target cells have different sets of genes. C) each cell converts that hormone to a different metabolite. D) the circulatory system regulates responses to hormones by routing the hormones to specific targets. E) a target cell's response is determined by the components of its signal transduction pathways.

E) a target cell's response is determined by the components of its signal transduction pathways.

When digested, fats are broken down into _____. A) glycerol only B) fatty acids only C) monosaccharides D) amino acids E) both glycerol and fatty acids

E) both glycerol and fatty acids

The smallest airway through which inspired air passes before gas exchange occurs in the mammalian lungs is the _____. A) bronchus B) larynx C) pharynx D) trachea E) bronchiole

E) bronchiole The bronchioles give rise to the alveoli, the site of gas exchange.

Starch can be broken down into the disaccharide known as _____. A) lactose B) glucose C) sucrose D) fructose E) maltose

E) maltose

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's A) secretory cell. B) regulatory cell. C) plasma cell. D) endocrine cell. E) target cell.

E) target cell.

Positive feedback differs from negative feedback in that A) positive feedback systems have control centers that are lacking in negative feedback systems. B) the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter. C) positive feedback benefits the organism, whereas negative feedback is detrimental. D) positive feedback systems have only effectors, whereas negative feedback systems have only receptors. E) the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.

E) the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.

True or False? The liver is a component of the alimentary canal. True False

False

True or false? One advantage of having a tube-like digestive tract is that digestion of all compounds can take place simultaneously down the tract. True False

False

The blood pressure in the glomerular capillaries is _________ than in the Bowman's capsule, so water and small solutes are forced out of the blood through capillary pores, leaving the larger components of the blood behind.

Higher

Regulatory homeostasis...

Involves adjusting the internal conditions of an organism to stay within a narrow range without regard to the external conditions.

The word "renal" refers to a

Kidney

In which region of the nephron is a steep osmotic gradient created? A) Collecting duct B) Loop of Henle C) Proximal tubule D) Distal tubule

Loop of Henle

Nephrons

Perform the work required to maintain water and electrolyte balance

Kidneys

Remove nitrogenous wastes from the blood and eliminate them in the urine

An integrator...

Sends instructions to an effector based on sensory information. *Eating raises blood sugar levels; insulin stimulates the lowering of blood sugar level. In this example the response to the stimulus (increased blood sugar levels) opposes that stimulus (by lowering blood sugar levels).

Urine formation in mammals...

Starts with filtration by the renal corpuscle. The volume and composition of the filtrate is modified as it progresses through the proximal tubule, loop of Henle, and distal tubule. Final adjustments to the filtrate take place in the collecting duct.

Making the collecting duct permeable to water results in...

The reabsorption of water

Urethra

The urethra transports urine from the urinary bladder to the world outside the body

True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions.

True