Bio 151 Animal Physiology

Digests peptides in the stomach. A. Gastrin B. Secretin C. Cholecystokinin D. Pepsin E. Lipase

D

Engulfing-phagocytic cells of innate immunity include _____. I) neutrophils II) macrophages III) dendritic cells IV) natural killer cells A) I and III B) II and IV C) I and IV D) I, II, and III

D

Which of the following do NOT synthesize and present MHC Class II molecules? (0) cytotoxic T cells (1) macrophages (2) dendritic cells (3) B cells (4) mast cells

0

12. Which of the following have androgen receptors? 0 = hypothalamus and anterior pituitary only 1 = hypothalamus and anterior pituitary and testis 2 = hypothalamus only 3 = anterior pituitary only 4 = portal veins only

1

An 18-year old woman presents at an Ob/Gyn clinic, concerned at the complete absence of menstrual cycles. She has obviously gone through puberty, but never remembers having any menstrual bleeds at any time. As part of the physician's work-up, a blood sample is taken from a vein in the woman's left arm and is checked for a variety of reproductive hormones. Three days later, the endocrine lab finds two very unexpected values on analyzing the blood sample. Circulating testosterone levels are extremely elevated for a woman. Circulating LH levels are also elevated and exceed the normal range for women. Upon further examination, the woman is found to have a pair of intra-abdominal testes, but no ovaries. In this individual, the most likely explanation for the testosterone and LH findings involves: 0 = defective, nonfunctional GnRH receptors 1 = defective, nonfunctional androgen receptors 2 = an autonomously functioning tumor involving GnRH neurons in the hypothalamus (a tumor that secretes hormone without the need for any stimulation) devoid of response to testosterone negative feedback 3 = defective, nonfunctional LH receptors 4 = an autonomously functioning pituitary gonadotrope cell tumor (a tumor that secretes hormone without the need for any stimulation) devoid of response to testosterone negative feedback

1

To provide an individual with effective, long-term immunity against a life-threatening virus that they have not yet encountered, the BEST and SAFEST approach would be to: (0) inject a solution containing concentrated and purified IgG produced by an immune response to the virus, (1) inject an attenuated form of the virus (has greatly diminished function) tagged to a molecule known to attract phagocytosis by the body's innate immune response cells, (2) inject a solution containing concentrated and purified helper T cells activated during an infection with this virus, (3) inject the active virus tagged to a molecule known to attract phagocytosis by the body's innate immune response cells, (4) inject a solution containing concentrated and purified cytotoxic T cells activated during an infection with this virus.

1

A 26-year old man is diagnosed with testicular cancer that has spread to both testicles. Surgery is required to remove both organs. After post-surgical chemotherapy, the man is found to be free of any obvious remaining cancer. During a series of post-surgical appointments at the Endocrine Clinic, the man is prescribed testosterone gel that he applies to his abdomen daily. Testosterone is absorbed into the general circulation through the skin. This treatment restores his circulating testosterone levels to their pre-surgery values since both testicles are no longer present. In comparing the man's blood hormone levels four weeks AFTER starting the testosterone treatment with immediately BEFORE starting the testosterone treatment, the Clinic finds the following: 0 = decreased circulating levels of testosterone (T) and increased circulating levels of luteinizing hormone (LH) 1 = no change in circulating levels of T and decreased circulating levels of LH 2 = increased circulating levels of T and decreased circulating levels of LH 3 = increased circulating levels of T and no change in circulating levels of LH 4 = increased circulating levels of T and increased circulating levels of LH

2

Several students present at Student Health Services in early March with a high fever (elevated body temperature) and feeling pretty lousy (unwell). They have been like this for four days and hope to find some therapeutic relief after seeing the health care providers. A blood test reveals elevated (above normal) levels of cytokines, IgM, IgG, helper T cells, and cytotoxic T cells. What is the most likely explanation for their condition? Note: this is NOT a Listeria bacterial infection. (0) an HIV (human immunodeficiency virus) infection contracted a year earlier (but unknown to the student), (1) stress from an 18-credit class load this semester, (2) a cold virus contracted from a generous, neighboring student in class, (3) a bacterial infection from eating contaminated food at one of our local eating establishments, (4) both options (1) and (2) only.

2

A male sports athlete has been taking large amounts of an anabolic steroid for 5 years to help improve and maintain his muscle mass. This anabolic steroid has a chemical structure similar to testosterone and it binds to the androgen receptor with androgen-typical biological effect. If a blood sample is taken from a vein in this man's arm, what circulating levels of testosterone (synthesized in the testis) will be found compared to those in normal men, and what levels of LH? The testosterone assay cannot detect the anabolic steroid the man is taking. 0 = normal circulating levels of testosterone (T) and normal circulating levels of luteinizing hormone (LH) 1 = high circulating levels of T and high circulating levels of LH 2 = high circulating levels of T and low circulating levels of LH 3 = low circulating levels of T and low circulating levels of LH 4 = low circulating levels of T and high circulating levels of LH

3

Which of the following experimental results would provide the most complete evidence that cytotoxic (killer) T cells must bind to both a fragment of non-self (foreign) antigen, such as a fragment of a virus, and an MHC Class I molecule before initiation of a cytolytic (cell killing) response by the cytotoxic T cell? Assume all of the following experiments occur in a culture dish containing purified cytotoxic cells and not in a living animal. (0) cytotoxic T cells from a mouse that has been infected with virus A will kill cells infected with virus A from a genetically identical mouse (1) cytotoxic T cells from a mouse that has been infected with virus A will not kill cells infected with virus A from an otherwise genetically identical mouse that differs only in the MHC I region of its genome (2) cytotoxic T cells from a mouse that has been infected with virus A will kill cells infected with virus A from an otherwise genetically identical mouse that differs only in the MHC I region of its genome (3) both options (0) and (1) only (4) both options (0) and (2) only

3

13. At which of the following locations will testosterone exert negative feedback? 0 = hypothalamus only 1 = anterior pituitary only 2 = hypothalamus and anterior pituitary and testis 3 = portal veins only 4 = hypothalamus, anterior pituitary only

4

HIV results in the devastating human disease of acquired immune deficiency syndrome or AIDS because: (0) it initially infects helper T cells, (1) it initially infects cytotoxic T cells, (2) some of its mutated forms no longer attract binding by the originally activated cytotoxic T cells when these HIV antigen fragments are presented by MHC Class I antigens on the surface of infected cells, (3) options (1) and (2) only, (4) options (0) and (2) only.

4

Which of the following DO synthesize and present MHC Class I molecules? (0) B cells (1) cytotoxic T cells (2) helper T cells (3) dendritic cells (4) All of the above

4

A patient has been taking pharmacological doses of a glucocorticoid, an anti-inflammatory drug, for a prolonged period to treat his ulcerative colitis auto-immune flare-ups. This drug binds to the glucocorticoid receptor, and is as biologically effective as cortisol but is not detected by the clinical laboratory's cortisol assay (and so will not register as "cortisol" in the assay). Which of the following would most likely be expected as laboratory values from a morning blood sample? A) Below normal levels of adenocorticotropic hormone (ACTH) and below normal levels of cortisol. B) Above normal levels of ACTH and above normal levels of cortisol. C) Below normal levels of ACTH and above normal levels of cortisol. D) Above normal levels of ACTH and below normal levels of cortisol. E) Normal levels of ACTH and normal levels of cortisol.

A

After the depolarization phase of an action potential, the resting potential is restored by _____. A) the opening of voltage-gated potassium channels and the closing of sodium channels B) a decrease in the membrane's permeability to potassium and chloride ions C) a brief inhibition of the sodium-potassium pump D) the opening of more voltage-gated sodium channels

A

Filtration in the juxtamedullary nephron takes place in the _____. A. glomerulus B. collecting duct C. proximal tubule D. ascending loop of henle

A

For a neuron with an initial membrane potential at -70 mV, an increase in the movement of sodium ions into that neuron's cytoplasm would result in the _____. A) depolarization of the neuron around that point on its cell membrane B) hyperpolarization of the neuron around that point on its cell membrane C) repolarization of the neuron around that point on its cell membrane D) replacement of sodium ions with calcium ions around that point on its cell membrane

A

For the successful development of a vaccine to be used against a pathogen, it is necessary that _____. A. the surface antigens of the pathogen stay the same B. all of the surface antigens on the pathogen be identified C. the pathogen has only one epitope D. the major histocompatability (MHC) molecules are heterozygous

A

For your internship at the local zoo, you have been assigned to help with the new orangutan-breeding program. Little is known about orangutan reproductive hormones, but hormone feedback cycles are often the same in closely related animals. You have been asked to use your knowledge of the interactions of human reproductive hormones to recommend injections to promote ovulation in a female orangutan when a visiting male arrives for a brief breeding visit. Refer to the paragraph above on the orangutan breeding program. Which of the following pairs of hormones will both have elevated levels in the blood at some time between the first day of a menstrual bleed and about two days before ovulation? A) estradiol and FSH B) estradiol and hCG C) testosterone and progesterone D) hCG and progesterone

A

Granulosa cells are stimulated by FSH and contribute to the development of the ovarian follicle. A) true B) false

A

If a molecule of carbon dioxide released into the blood in your left toe is exhaled from your nose, it must pass through all of the following EXCEPT _____. A. the pulmonary vein B. an alveolus C. the trachea D. the right atrium

A

In the stomach, protein digestion is enabled by: A. gastrin stimulation of ECL, parietal and chief cells, B. acetylcholine stimulation of G cells, C. gastrin-releasing hormone stimulation of goblet cells, D. pepsinogen stimulation of ECL cells

A

Inflammatory responses typically include _____. A) increased activity of phagocytes in an inflamed area B) reduced permeability of blood vessels to conserve plasma C) release of substances to decrease the blood supply to an inflamed area D) inhibiting the release of white blood cells from bone marrow

A

Innate immunity _____. A) is activated immediately upon infection B) depends on an infected person'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 humans

A

Myocardial cells are specialized muscle cells that can initiate and conduct an action potential (ion flow. Before this can occur, however, the cell needs to change ionic concentrations in its cytoplasm so that it moves in a negative direction with respect to the electrochemical chemical gradient with the surrounding extra-cellular fluid, such as moving from +20mV to -70mV. This process is called_______________. A. repolarization B. depolarization C. resting state D. saltatory conduction

A

Once labor begins in childbirth, contractions increase in intensity and frequency, causing more contractions to occur until delivery. The increasing labor contractions of childbirth are an example of which type of regulation? A. positive feedback B. negative feedback C. feedback inhibition D. enzymatic catalysis

A

Parasympathetic nervous system innervation of the heart "pacemaker" slows heart rate by releasing ____________ resulting in the ______________. A. acetylcholine (ACh.; opening of more K+ channels, decreasing the rate of depolarization and thus delaying the opening of Ca++ channels. B. acetylcholine (ACh.; opening of more K+ channels, increasing the rate of repolarization and thus accelerating the opening of Ca++ channels C. norepinephrine (NE.; earlier opening of Na+ channels during repolarization and thus accelerating the opening of Ca++ channels. D. norepinephrine (NE.; later opening of Na+ channels during repolarization and thus delaying the opening of Ca++ channels.

A

Parietal cells in gastric pits release _______? A. hydrogen and chloride ions that combine into an acid that unfolds large proteins making them vulnerable to enzymatic attack by pepsin, a proteolytic enzyme that functions optimally in acidic environment, B. pepsinogen, an inactive form of a proteolytic enzyme, that once unfolded in an acidic environment, cleaves itself into pepsin, the active enzyme, C. histamine that stimulates ECL cells to release pepsinogen, D. gastrin into the stomach lumen, enabling gastrin to unfold large proteins making them vulnerable to pepsin-mediated digestion.

A

People with type II diabetes mellitus have defective insulin receptors that cannot respond to insulin properly. Relative to normal individuals, what would be the effect on blood glucose levels under conditions of chronic stress that kept blood cortisol levels high? There would be _____. A. a greater increase in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals B. less increase in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals C. be a greater decrease in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals D. less decrease in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals

A

Presents fragments of peptides made within a cell for binding to cytotoxic T cells A. MHC Class I molecule B. MHC Class II molecule C. Cytokine D. Perforin

A

Select A if statement A is greater than B Select B if statement B is greater than A Select C if the two statements are equal, or very nearly equal A. The time taken for a stressor to stimulate an increase in blood levels of cortisol B. The time taken for a stressor to stimulate an increase in blood levels of adrenalin (epinephrine)

A

Stimulates parietal cells to release hydrochloric acid. A. Gastrin B. Secretin C. Cholecystokinin D. Pepsin E. Lipase

A

This structure in the cell membrane of myocardial cells is crucial for maintaining or regaining their negative electrochemical gradient of -60 to -90 mV. It is the ______________. A. Na+/K+ ATPase pump B. Na+ channel C. Ca++ channel D. Cl- channel

A

To achieve optimum effectiveness in promoting exchange or movement of fluids or molecules from one body compartment or system to another, such as from the lumen of the gastro-intestinal tract to the extra-cellular fluid surrounding the baso-lateral membrane of enterocytes, evolution has favored development of a gastro-intestinal tract with _____. A. more branching or folds, and finger-like projections on apical cell membranes B. increased thickness and more rigid extra-cellular matrix C. larger enterocyte cells with increased vesicle capacity for storage D. decreased blood supply

A

Vaccination of a person with an attenuated virus (has greatly reduce function) increases the number of __________. A. lymphocytes with receptors that can bind to the pathogen B. epitopes that the immune system can recognize C. macrophages specific for a pathogen D. major histocompatability (MHC. molecules that can present an antigen

A

What major advantage is conveyed by having a system of adaptive immunity? A) It enables a rapid defense against an antigen that has been previously encountered. B) It enables an animal to counter most pathogens almost instantly the first time they are encountered. C) It results in effector cells with specificity for a large number of antigens. D) It allows for the destruction of antibodies.

A

When the beta cells of the pancreas release insulin into the blood, _____. A. the skeletal muscles and the adipose cells take up glucose at a faster rate B. the liver catabolizes glycogen C. the alpha cells of the pancreas release glucose into the blood D. the kidneys begin gluconeogenesis

A

Which of the following conditions would most likely be due to high blood pressure in a mammal? A. bursting of blood vessels in capillary beds B. inability of the right ventricle to contract C. reversal of normal blood flow direction in arteries D. destruction of red blood cells

A

During the ________ of the menstrual cycle, circulating levels of luteinizing hormone (LH) reach maximum values: A. day before and day of ovulation B. luteal phase C. late follicular phase D. last day of a menstrual cycle (2 ANSWERS)

A, C

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 to the thumb and then back to the left ventricle, this red blood cell must pass through at least _____. A. one capillary bed B. two capillary beds C. three capillary beds D. four capillary beds

B

A toxin that binds specifically to voltage-gated sodium channels in axons, and blocking their action, would be expected to _____. A) prevent the hyperpolarization phase of the action potential B) prevent the depolarization phase of the action potential C) prevent graded potentials D) increase the release of neurotransmitter molecules

B

All myocardial cells have an endogenous rhythm of depolarization and contraction. To prevent chaotic and disorganized contractions within the heart, there is an anatomically and functionally distinct "pacemaker" that normally depolarizes first. That structure is the _______. A. atrioventricular node B. sinoatrial node C. right atrium D. purkinje fibers

B

An example of a properly functioning homeostatic control system is seen when _____. A. the core body temperature of a runner rises gradually from 37°C to 45°C 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 blood pressure increases in response to an increase in blood volume

B

An example of antagonistic or opposing hormones controlling homeostasis would be _____. A. thyroxine and parathyroid hormone in calcium balance B. insulin and glucagon in glucose metabolism C. progestins and estrogens in sexual differentiation D. epinephrine and norepinephrine in fight-or-flight responses

B

An inactivating mutation in the progesterone receptor gene would likely result in _____. A. the absence of secondary sex characteristics B. the inability of the uterus to support pregnancy C. enlarged and hyperactive uterine endometrium, the tissue that normally accommodates the implantation of an embryo after fertilization D. the absence of mammary gland development

B

Analysis of a blood sample from a fasting individual who had not eaten for twenty-four hours would be expected to reveal high levels of _____. A. insulin B. glucagon C. gastrin D. glucose

B

B cells become activated only after binding to cytotoxic T cells. A) true B) false

B

Because the foods eaten by humans are often composed largely of macromolecules, we need to have mechanisms for _____. A. dehydration synthesis B. acid and enzymatic hydrolysis C. regurgitation D. demineralization

B

Clonal selection is an explanation for how _____. A) V, J, and C gene segments are rearranged B) an antigen can provoke production of high levels of specific antibodies C) HIV (human immunodeficiency virus) can disrupt the immune system D) macrophages can recognize specific T cells and B cells

B

Compared with a smaller cell, a larger cell of the same shape has _____. A. less surface area B. less surface area per unit of volume C. a smaller average distance between its mitochondria and the external source of oxygen D. a smaller cytoplasm-to-nucleus ratio

B

During the ________ of the menstrual cycle, circulating levels of progesterone reach maximum values: A. first day of a menstrual period B. luteal phase C. late follicular phase D. last day of a menstrual cycle

B

Enterocytes accumulate these absorbed molecules into chylomicrons enabling their transport in aqueous, fluid-filled, transport systems: A. glucose B. fatty acids C. amino acids D. water

B

Examine the digestive system structures in the figure above. Most of the digestion of fats occurs in structure(s) _____. A. 3 only B. 4 only C. 1 and 4 D. 3 and 4

B

Examine the digestive system structures in the figure above. The parasympathetic nervous system releases acetylcholine (Ach) to stimulate histamine, gastric juice and pepsinogen release in location _____. A. 1 B. 3 C. 8 D. 9

B

Granulosa cells in ovarian follicles growing in the first few days of a menstrual cycle are stimulated by ________ binding to its receptor on these cells, enabling the cells to contribute to the growth and development of the ovarian follicle. A) Progesterone B) FSH C) LH D) hCG

B

Granulosa cells in the single, dominant ovarian follicle growing in the last 2-3 days before ovulation are stimulated by ________ and __________ binding to their receptor on these cells, enabling the cells to contribute to the growth and development of the ovarian follicle. A) Progesterone and hCG B) FSH and LH C) LH and progesterone D) hCG and testosterone

B

Histamine is secreted from neutrophils during an inflammatory response. A) true B) false

B

If ATP production in a human kidney was suddenly halted, urine production would _____. A. decrease, and the urine would be hypoosmotic compared to plasma B. increase, and the urine would be isoosmotic compared to plasma C. increase, and the urine would be hyperosmotic compared to plasma D. decrease, and the urine would be isoosmotic compared to plasma

B

If a person has a congenital abnormality resulting in partially defective glucose transporter molecules (GLUT4) in muscle and fat cells: A) circulating cortisol levels will be elevated to maintain normal blood glucose levels. B) circulating insulin levels will be elevated to maintain normal blood glucose levels. C) circulating glucagon levels will be elevated to maintain normal blood glucose levels. D) circulating oxytocin levels will be elevated to maintain normal blood glucose levels. E) circulating insulin levels will be lowered to maintain normal blood glucose levels.

B

Imagine that a woman is in the final week of her pregnancy. Her doctor gives her an injection of oxytocin. The likely result of this is that the pregnant woman would _____. A) stop secreting prostaglandins from the placenta B) undergo vigorous contractions of her uterine muscles C) increase the synthesis and secretion of progesterone D) be prevented from lactation or breast feeding

B

In multiple sclerosis, the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results due to (auto)immune attack on myelin. How does this disease manifest at the level of the action potential? This is before any neuronal cell death that might occur due to de-myelination. I) Action potentials move in the opposite direction on the axon. II) Action potentials move more slowly along the axon. III) No action potentials are transmitted. A) only I B) only II C) only III D) only I and III

B

In response to stress, the adrenal gland promotes the synthesis of glucose from non-carbohydrate substrates via the action of the steroid hormone _____. A. glucagon B. cortisol C. thyroxine D. adrenocorticotropic hormone (ACTH)

B

Ingested dietary substances must cross cell membranes to be used by the body. For glucose, absorption is enabled by _____ in the apical membrane of enterocytes. A. Na+/amino acid co-transporters B. Na+/glucose co-transporters C. Aquaporin-3 D. Na+/K+ ATP-ase pumps

B

Jahasz-Pocsine and co-workers found a correlation between gastric bypass surgery and neurological complications. Surgeons performed gastric bypass surgery on 150 patients at the University of Arkansas for Medical Sciences Neurology Clinic. Of the 150 patients, 26 experienced neurological complications related to the surgery. What is the most likely cause for the neurological complications? A. sudden weight loss and caloric deficiency interfering with neurological function B. nutrient (for example, glucose, amino acid, vitamin and mineral. deficiencies C. sloppy surgical technique of physicians performing the bypass surgery D. infections following surgical intervention

B

Macrophages have specific IgM antigen receptors that enable them to bind to non-self antigens. A) true B) false

B

Mark A if statement A is greater than B Mark B if statement B is greater than A Mark C if the two statements are equal, or very nearly equal A. Diastolic blood pressure B. Systolic blood pressure

B

Myocardial cells are specialized muscle cells that can initiate and conduct an action potential (ion flow. An action potential is triggered by the cytoplasm of the cell moving in a positive direction with respect to the electrochemical chemical gradient with the surrounding extra-cellular fluid, such as moving from -90mV to -50mV. This process is called_______________. A. repolarization B. depolarization C. resting state D. saltatory conduction

B

Opening of ligand-gated Na+ ion channels on the dendrite of a neuron will result in _______ in the surrounding membrane of the same neuron: A. repolarization B. depolarization C. generation of an action potential D. undershoot

B

Ovulation is under ______________ control. A) Negative feedback B) Positive feedback C) Opposing systems D) Stimulus-response

B

Ovulation is under negative feedback control. A) true B) false

B

Positive feedback differs from negative feedback in that _____. A. positive feedback benefits the organism, whereas negative feedback is detrimental B. positive feedback is required to achieve a goal or complete a process, while negative feedback maintains optimum conditions C. the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter D. positive feedback systems have only effectors, whereas negative feedback systems have only receptors

B

Presents fragments of peptides made outside your cells for binding to helper T cells A. MHC Class I molecule B. MHC Class II molecule C. Cytokine D. Perforin

B

Select the pathway that would lead to the activation of cytotoxic T cells. A. helper T cell binds free-floating virus not associated with any cell in extra-cellular fluid → helper T cell is activated → clonal selection occurs B. body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface C. complement is secreted → B cell contacts antigen → helper T cell activated → cytokines released D. cytotoxic T cells → class II MHC molecule-antigen complex displayed → cytokines released → cell lysis

B

Similar to the formation of spermatozoa, formation of oocytes begins at puberty. A) true B) false

B

Spermatogenesis is completed before birth and awaits maturation of the male hypothalamic-pituitary-testicular endocrine system to manage and release the already formed male germ cells. A) true B) false

B

Stimulates the release of cholecystokinin. A. Gastrin B. Secretin C. Cholecystokinin D. Pepsin E. Lipase

B

Tadpoles must undergo a major metamorphosis to become frogs. This change includes reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in rhodopsin in the eye, development of lungs, change in hemoglobin structure, and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore. Amazingly, all of these changes are induced by thyroxine. What is the most likely explanation for such a wide array of effects of thyroxine? A. There are many different forms of thyroxine, each specific to a different tissue. B. Different tissues have thyroxine receptors that activate different signal transduction pathways. C. Some tissues have membrane receptors for thyroxine, while other tissues have thyroxine receptors within the nucleus. D. Different releasing hormones release thyroxine to different tissues.

B

The "undershoot" phase of hyperpolarization is due to _____. A) slow opening of voltage-gated sodium channels B) sustained opening of voltage-gated potassium channels C) rapid opening of voltage-gated calcium channels D) slow restorative actions of the sodium-potassium ATPase

B

The force driving simple diffusion is _____, while the energy source for active transport is _____. A. the concentration gradient; ADP B. the concentration gradient; ATP C. transmembrane pumps; electron transport D. phosphorylated protein carriers; ATP

B

The highest rate of nutrient absorption occurs_____. A. large intestine B. small intestine C. duodenum D. liver

B

The pancreas is involved in the digestion of _____. I. protein II. fat III. carbohydrates A. I and III B. I, II, and III C. II and III, D. III only

B

The primary function of the corpus luteum is to _____. A) nourish and protect the egg cell B) maintain progesterone and estrogen synthesis after ovulation has occurred C) stimulate the development of the mammary glands D) support pregnancy in the second and third trimesters

B

Which of the following is crucial to activation of the adaptive immune response? A) memory cells B) presentation of MHC (major histocompatibility complex)-antigen complex on a cell surface C) somatic hypermutation D) phagocytosis of antibody-antigen complex by macrophages in the blood (the humoral response

B

Why are action potentials usually conducted in one direction? A) The nodes of Ranvier conduct potentials in one direction. B) The brief refractory period prevents reopening of voltage-gated Na+ channels. C) The axon hillock has a higher membrane potential than the terminals of the axon. D) Voltage-gated channels for both Na+ and K+ open in only one direction.

B

Why are the renal artery and vein critical to the process of osmoregulation in the kidney? A. The kidneys require constant and abnormally high oxygen supply to function. B. The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys. C. The kidneys require higher than normal levels of hormones. D. The renal artery and vein are the main pathways regulating how much is produced by the kidneys.

B

You are a physician and a patient comes to your office with high body temperature, profuse sweating, weight loss, and high blood pressure. These are clear signs of hyperthyroidism, a pathophysiological state of over-secretion of thyroid hormones (T3 and T4). The following blood test results confirm this: below normal levels of TRH (thyrotropin releasing hormone) higher than normal levels of TSH (thyroid stimulating hormone) higher than normal levels of T3 and T4 (thyroid hormones) You suspect that a tumor, unresponsive to negative feedback, may be responsible. Using the blood test results and the feedback diagram above, determine the location of the tumor. A) The patient has a hypothalamic TRH secreting tumor. B) The patient has an anterior pituitary TSH secreting tumor. C) The patient has a thyroid gland T3/T4 secreting tumor. D) The patient has a T3/T4 secreting tumor in an organ system separate from the hypothalamus, pituitary and thyroid gland. E) The patient has a TRH secreting tumor in an organ system separate from the hypothalamus, pituitary and thyroid gland.

B

You are a student listening to a lecture in Biology 152, when the lecturer invites you to come out to the front of the class and continue the lecture. Which of the following might you experience immediately? A. increased circulating concentrations of cortisol. B. increased circulating concentrations of adrenalin (epinephrine). C. decreased blood levels of ACTH. D. increased blood levels of estrogen.

B

A certain cell type has existed in the blood and tissue of its human host's immune system for over twenty years. One day, it recognizes a newly arrived antigen and binds to it, subsequently triggering a secondary immune response in the body. Which of the following cell types most accurately describes this cell? A) plasma cell B) thyroid cell C) memory cell D) macrophage

C

A disease that destroys both the right and left adrenal cortex should lead to an increase in the plasma levels of _____. A. glucocorticoid hormones, including cortisol B. epinephrine C. adrenocorticotropic hormone (ACTH) D. insulin

C

A newborn infant who is accidentally given a drug that destroys the thymus would most likely _____. A. lack innate immunity B. be unable to genetically rearrange antigen receptors C. be unable to differentiate and mature T cells D. have a reduced number of B cells and be unable to form antibodies

C

A stroke volume of 70 mL/cardiac cycle in a heart with a pulse of 72 cycles per minute results in a cardiac output of about 5 liters per minute at a typical, healthy resting left ventricle systolic pressure of _____. A. 25 mm Hg (Hg = mercury; mm Hg = unit of pressure. B. 400 mm Hg C. 120 mm Hg D. 70 mm Hg

C

Action potentials move along axons _____. A) more slowly in axons of large than of small diameter B) by activating the sodium-potassium "pump" at each point along the axonal membrane C) more rapidly in myelinated than in non-myelinated axons D) by reversing the concentration gradients for sodium and potassium ions

C

After drinking alcoholic beverages, increased urine excretion is the result of _____. A. increased aldosterone production B. increased blood pressure C. inhibited secretion of antidiuretic hormone (ADH) D. increased reabsorption of water in the proximal tubule

C

An MRI scan detects nervous tissue degeneration in the posterior pituitary gland of a patient. Which of the following will be found? A. glucose levels in the blood will be abnormally low B. ACTH levels in the blood will be abnormally low C. oxytocin levels in the blood will be abnormally low D. cortisol levels in the blood will be abnormally low E. CRH levels in the blood will be abnormally high

C

An elephant and a mouse are running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster? A. The elephant will because it has the higher surface-area-to-volume ratio. B. The elephant will because it has the lower surface-area-to-volume ratio. C. The mouse will because it has the higher surface-area-to-volume ratio. D. They will cool at the same rate because they overheated by the same amount.

C

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 __________. A. a complement B. antibodies C. class I MHC molecules D. class II MHC molecules

C

CD4 and CD8 are _____. A. proteins secreted by antigen-presenting cells B. receptors present on the surface of natural killer cells C. molecules present on the surface of T cells where they interact with major histocompatability (MHC) molecules D. molecules on the surface of antigen-presenting cells where they enhance B cell activity

C

Damage to the sinoatrial node in humans _____. A. would block conductance between the bundle branches and the Purkinje fibers B. would have a negative effect on peripheral vessel resistance to blood flow C. would disrupt the rate and timing of cardiac muscle contractions D. would only have a direct effect on blood pressure baroreceptors (mechanoreceptor sensory neurons that are excited by stretch of a major artery. in the aorta

C

During a stress response: A) ACTH released from the posterior pituitary stimulates cortisol release from the adrenal cortex. B) ACTH released from the hypothalamus in the brain stimulates cortisol release from the adrenal cortex. C) Cortisol released from the adrenal cortex stimulates glucose release from the liver. D) Cortisol released from the adrenal cortex stimulates glucose release from the pancreas. E) ACTH released from the anterior pituitary stimulates cortisol release from the adrenal medulla.

C

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of _____. A. a negative feedback system B. a hormone that acts in an antagonistic way with another hormone C. a hormone that is involved in a positive feedback loop D. signal transduction immediately changing gene expression in its target cells

C

During the ________ of the menstrual cycle, circulating levels of estradiol reach maximum values. A. first day of a menstrual period B. luteal phase C. late follicular phase D. last day of a menstrual cycle

C

During the cardiac cycle: A. atrial and ventricular systole occur simultaneously and the semi-lunar valves are opened. B. the ventricles contract simultaneously and the atrioventricular valves are opened. C. the atrioventricular valves are closed during ventricular systole. D. when the ventricles contract simultaneously, the atria enter diastole and the atrioventricular valves are opened. E. when the atria contract simultaneously, the ventricles enter diastole and the atrioventricular valves are closed.

C

Enterocytes release this when directly stimulated by fatty acids in the acid chyme entering the duodenum. A. Gastrin B. Secretin C. Cholecystokinin D. Pepsin E. Lipase

C

Extra-cellular fluid is _____. A. the internal environment inside animal cells B. identical to the composition of blood C. a common site of exchange between blood and body cells D. found only in the lumen of the small intestine

C

For your internship at the local zoo, you have been assigned to help with the new orangutan-breeding program. Little is known about orangutan reproductive hormones, but hormone feedback cycles are often the same in closely related animals. You have been asked to use your knowledge of the interactions of human reproductive hormones to recommend injections to promote ovulation in a female orangutan when a visiting male arrives for a brief breeding visit. Refer to the paragraph above on the orangutan breeding program. Which of the following hormones would you use daily if you want to induce ovulation, starting 1-2 days after the onset of a menstrual period bleed? A) estradiol (estrogen) for several days and then a day of testosterone B) progesterone for several days and then a day of estradiol C) follicle stimulating hormone (FSH) for several days and then a day of luteinizing hormone (LH) D) human chorionic gonadotropin (hCG) for several days and then a day of luteinizing hormone (LH)

C

If a person has a congenital abnormality resulting in defective ACTH receptors (i.e., the receptors do not bind ACTH well and are much less able to engage ACTH biological action): A) circulating cortisol levels will be low and ACTH levels will be low. B) circulating insulin levels will be extremely low. C) circulating cortisol levels will be low and ACTH levels will be high. D) circulating ACTH levels will be normal and cortisol levels will be low. E) circulating ACTH and cortisol levels will be normal.

C

In correct chronological order, the three phases of the human ovarian or menstrual cycle from days 1 through 28 are _______. A) follicular → luteal → ovulatory B) menstrual → secretory → proliferative C) follicular → ovulation → luteal D) ovulation → luteal → follicular

C

In humans, the transport epithelial cells in the ascending loop of Henle _____. A. are the largest epithelial cells in the body B. are not in contact with interstitial fluid C. have plasma membranes of low permeability to water D. are not affected by high levels of nitrogenous wastes

C

In humans, the transport epithelial cells in the descending loop of Henle enable water re-absorption while losing little or no salt from the nephron filtrate because _____. A. they express low numbers of aquaporins in their apical membranes B. they express high numbers of Na+/K+ ATPase pumps in their apical membranes C. they express low numbers of Na+/K+ ATPase pumps and Na+ ion channels D. they express cell membrane receptors for antidiuretic hormone (ADH)

C

In which of these blood vessels is the velocity of blood flow the slowest? A. arteries B. arterioles C. capillaries D. venules E. veins

C

Ingested dietary substances must cross cell membranes to be used by the body. For fatty acids, absorption is enabled by _____ in the apical membrane of enterocytes. A. Na+/fatty acid co-transporters B. Na+/glucose co-transporters C. Fatty acid transporters D. Chylomicrons

C

Is secreted by a helper T cell to activate a bound B cell A. MHC Class I molecule B. MHC Class II molecule C. Cytokine D. Perforin

C

Is secreted by activated helper T cells to amplify a cell-mediated response A. MHC Class I molecule B. MHC Class II molecule C. Cytokine D. Perforin

C

Jenner's successful use of cowpox virus as a vaccine against the smallpox virus was due to the fact that _____. A. the immune system responds nonspecifically to antigens B. the cowpox virus made antibodies in response to the presence of smallpox C. there are some epitopes (antigenic determinants) common to both pox viruses D. cowpox and smallpox are caused by the same virus

C

Lymphocytes (B and T cells) mature in the _____. I. spleen II. thymus III. bone marrow A. only I and III B. only I and II C. only II and III D. I, II, and III

C

Mark A if statement A is greater than B Mark B if statement B is greater than A Mark C if the two statements are equal, or very nearly equal A. Volume of blood pumped out of the right ventricle of the heart at ventricular systole B. Volume of blood pumped out of the left ventricle of the heart at ventricular systole

C

Most types of communication between cells utilize _____. A. the exchange of cytosol between the cells B. the movement of the cells C. chemical or electrical signals D. the exchange of DNA between the cells

C

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. their reliance on signal transduction in the cell

C

Sympathetic nervous system innervation of the heart "pacemaker" accelerates heart rate by releasing ____________ resulting in the ______________. A. acetylcholine (ACh.; opening of more K+ channels, decreasing the rate of depolarization and thus delaying the opening of Ca++ channels. B. acetylcholine (ACh.; opening of more K+ channels, increasing the rate of repolarization and thus accelerating the opening of Ca++ channels C. norepinephrine (NE.; earlier opening of Na+ channels during repolarization and thus accelerating the opening of Ca++ channels. D. norepinephrine (NE.; later opening of Na+ channels during repolarization and thus delaying the opening of Ca++ channels.

C

The "threshold" potential of a membrane is the _____. A) lowest frequency of action potentials a neuron can produce B) minimum hyperpolarization needed to prevent the occurrence of action potentials C) minimum depolarization needed to operate the voltage-gated sodium and potassium channels D) peak amount of depolarization seen in an action potential

C

The absorption of fats differs from that of carbohydrates in that _____. A. fat absorption primarily occurs in the stomach, whereas carbohydrates are absorbed from the small intestine B. carbohydrates need to be emulsified before they can be digested, whereas fats do not C. most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood D. fats, but not carbohydrates, are digested by bacteria before absorption

C

The active ingredient in the statin, orlistat, acts to decrease the amount of fat that is absorbed by attaching to enzymes that digest fat. Which of the following are potential targets of orlistat? A. salivary amylase B. pepsidase C. pancreatic lipase D. secretin

C

The cells and signaling molecules involved in the initial stages of the inflammatory response are _____. A) phagocytes and chemokines B) dendritic cells and interferons C) mast cells and histamines D) lymphocytes and interferons

C

This structure in the cell membrane of myocardial cells is crucial for enabling entry of ions from the extra-cellular fluid into the cytoplasm that will trigger that myocardial cell to contract and will flow through to neighboring cells across gap junctions to initiate their depolarization and contraction. It is the ______________. A. Na+/K+ ATPase pump B. Na+ channel C. Ca++ channel D. Cl- channel

C

Two sophomore undergraduate students studying for their animal physiology quiz decide to take a break for a lunchtime burger. Before reaching the cafeteria, nervous impulses from the parasympathetic nervous system, via the dorsal vagal complex, will initiate gastric secretion by triggering release of which molecule? A. norepinephrine B. vasoactive intestinal polypeptide (VIP) C. gastrin-releasing peptide (GRP) D. nitric oxide

C

Villi and microvilli in the small intestine _____. A. neutralize stomach acid B. activate trypsinogen C. increase the surface area to increase the efficiency of nutrient absorption D. emulsify lipid molecules

C

What will be the long-term effect of blocking the lymphatic vessels associated with a capillary bed? A. more fluid entering the venous capillaries B. an increase in the blood pressure in the capillary bed C. the accumulation of more fluid in the extra-cellular fluid surrounding cells around the capillary bed (edema) D. a blockage in the capillary bed

C

When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of _____. A. negative feedback B. positive feedback C. opposing systems D. protein-protein interactions

C

Which of the following develops the greatest pressure on the blood in the human aorta? A. systole of the left atrium B. diastole of the right ventricle C. systole of the left ventricle D. diastole of the right atrium

C

Which of the following organs is correctly paired with its function? A. stomach — protein absorption B. large intestine — bile production C. small intestine — glucose absorption D. pancreas — starch absorption

C

Which of the following statements about action potentials is correct? A) Action potentials for a given neuron vary in magnitude. B) Action potentials for a given neuron vary in duration. C) Action potentials are propagated down the length of the axon. D) Movement of ions during the action potential occurs mostly through the sodium pump.

C

Which of the following statements are fundamental to the clonal-selection and expansion theory of how the adaptive immune system functions? I. Each lymphocyte has a unique membrane receptor that recognizes one antigen. II. When the lymphocyte binds an antigen, it is activated and begins dividing to form many identical copies of itself. III. Only when a lymphocyte is infected by a virus does it undergo activation. IV. A clone of lymphocytes descend from a single activated lymphocyte and persist even after the pathogen is eliminated. A. only I and III B. only II and IV C. only I, II, and IV D. only II, III, and IV

C

Which pair incorrectly associates a physiological process with the appropriate hormone? A. release of stomach gastric juice — gastrin B. release of bicarbonate solution from the pancreas into the duodenum via the bile duct — secretin C. release of amylase from the pancreas into the duodenum via the bile duct — prolactin D. release of bile from the gall bladder into the duodenum via the bile duct — cholecystokinin (CCK)

C

Why do Na+ ions enter the cell when voltage-gated Na+ channels are opened in neurons? A) because the Na+ concentration is much lower outside the cell than it is inside B) because the Na+ ions are actively transported by the sodium-potassium pump into the cell C) because the Na+ concentration is much higher outside the cell than it is inside, and the Na+ ions are attracted to the negatively charged interior D) because the Na+ concentration is much higher outside the cell than it is inside, and the Na+ ions are actively transported by the sodium-potassium pump into the cell

C

A laboratory identifies two distinct forms of glucocorticoid receptor (receptors that bind cortisol). Glucocorticoid hormone receptor 1 (GR1) is expressed in many organ systems, but not in the brain or the anterior pituitary, while glucocorticoid receptor 2 (GR2) is expressed exclusively in the brain and anterior pituitary. Both receptors bind cortisol equally and engage cortisol biological action. A patient is identified with a mutation in GR2 that renders that specific glucocorticoid receptor non-functional (will not bind cortisol and will not enable cortisol's biological action). GR1 remains fully functional. Which physiological and endocrinological abnormalities will accompany this mutant GR2 genotype in the patient? In considering the following options, do NOT include in your thinking how insulin, glucagon, adrenalin (epinephrine) or the kidney might influence the proposed changes. A) Decreased circulating levels of ACTH, increased circulating levels of cortisol, elevated circulating levels of glucose and fatty acids. B) Decreased circulating levels of ACTH, decreased circulating levels of cortisol, elevated circulating levels of glucose and fatty acids. C) Increased circulating levels of ACTH, increased circulating levels of cortisol, decreased circulating levels of glucose and fatty acids. D) Increased circulating levels of ACTH, increased circulating levels of cortisol, elevated circulating levels of glucose and fatty acids. E) Increased circulating levels of ACTH, decreased circulating levels of cortisol, decreased circulating levels of glucose and fatty acids.

D

A patient with a pulse rate of 70 beats/minute and a stroke volume of 70 mL/beat (milliliters per beat) will have a cardiac output of _____. A. 1,000 mL/minute B. 1,750 mL/minute C. 2,800 mL/minute D. 4,900 mL/minute

D

A physician finds that a nine-year-old female patient is entering puberty much earlier than is usual. Such a condition is most likely the result of a tumor in the _____. A. hypothalamus, producing elevated levels of estradiol B. anterior pituitary, producing elevated levels of estradiol C. ovaries, producing elevated levels of cortisol D. anterior pituitary, producing elevated levels of LH and FSH

D

A pregnant woman comes into the hospital past her due date. The doctor decides it is time for the baby to be delivered. Before performing a cesarean section, the doctor wants to try to induce labor. Which of the following would she most likely inject? A. progesterone B. luteinizing hormone (LH) C. follicle-stimulating hormone (FSH) D. oxytocin

D

A reproductive hormone that is secreted directly from a structure in the brain is _____. A) estradiol B) progesterone C) follicle-stimulating hormone (FSH) D) gonadotropin-releasing hormone (GnRH)

D

Arrange in the correct sequence these components of the mammalian immune system as it first responds to a pathogen. I. Pathogen is destroyed. II. Lymphocytes secrete antibodies. III. Antigenic determinants from pathogen bind to antigen receptors on lymphocytes. IV. Lymphocytes specific to antigenic determinants from pathogen become numerous. V. Only memory cells remain. A. I → III → II → IV → V B. II → I → IV → III → V C. IV → II → III → I → V D. III → IV → II → I → V

D

Atria contract _____. A. just prior to the beginning of diastole B. during diastole C. immediately after systole D. during systole

D

Clonal selection and differentiation of B cells activated by antigen exposure leads to the production of _____. A) large quantities of the antigen initially recognized B) vast numbers of B cells with random antigen-recognition receptors C) long-lived erythrocytes that can later secrete antibodies for the antigen D) short-lived plasma cells that secrete antibodies for the antigen

D

Establishment of electrochemical gradients are key to the successful function of many cells, including enterocytes tasked with absorption of nutrients and water. One energy-consuming, membrane-bound cell structure is vital for enabling glucose, amino acid and water absorption: A. GLUT2 glucose transporter B. Na+/amino acid co-transporter C. Na+ ion channel D. Na+/K+ pump

D

Following the arrival of acid chyme in the small intestine, amino acids in the acid chyme stimulate: A. the release of cholecystokinin from the pancreas to activate peptide digesting enzymes. B. the release of gastrin from the wall of the duodenum to activate the release of peptide digesting enzymes from the pancreas. C. the release of secretin from the wall of the duodenum to stimulate the gall bladder to release peptide digesting enzymes. D. the release of cholecystokinin from the wall of the duodenum to stimulate the pancreas to release peptide digesting enzymes. E. the release of gastric juice from the wall of the duodenum to stimulate the pancreas to release peptide digesting enzymes

D

If a person loses a large amount of water in a short period of time, he or she may die from dehydration. Antidiuretic hormone (ADH) can help reduce water loss through its interaction with its receptors on its target cells in the kidney nephron _____. A. proximal tubule B. loop of Henle C. glomerulus D. collecting ducts

D

If a person loses a large amount of water in a short period of time, he or she may die from dehydration. Antidiuretic hormone (ADH) can help reduce water loss through its interaction with its target cells in the _____. A. anterior pituitary B. posterior pituitary C. proximal tubules of kidney nephrons D. collecting ducts of kidney nephrons

D

Immunological memory accounts for _____. A) the human body's ability to distinguish self from non-self B) the observation that some strains of the pathogen that causes dengue fever cause more severe disease than others C) the ability of a helper T cell to signal B cells via cytokines D) the ancient observation that someone who had recovered from the plague could safely care for those newly diseased

D

In a resting potential of a neuron in the brain, a typical example of a cation that is more abundant in its cytoplasm than it is in the extra-cellular fluid outside the neuron is _____. A. Cl- B. Ca++ C. Na+ D. K+

D

In the heart, there needs to be a short pause between atrial systole and ventricular systole to enable the atria to over-pack each ventricle with about 75ml of blood and optimize the volume pumped to both circulation circuits. The pause of about 0.1 sec is provided by slow conduction of the electrical signal across or through the _________. A. sinoatrial node B. right atrium C. purkinje fibers D. atrioventricular node

D

In type 2 diabetes, one of the major pathophysiological changes involves a reduction in the ability of insulin to stimulate cells to take up glucose after insulin binds to its cell surface receptor. Which of the following provide the MOST COMPLETE evidence consistent with this understanding? A. Early morning blood insulin levels are diminished below those normally found first thing in the morning (that is after an overnight fasting period, unless you eat while sleeping!) B. Blood glucose levels, 2 hours after receiving a measured oral dose of glucose, are elevated above 200 mg/dl compared to those normally found at this time (<140 mg/dl) after taking the same oral dose of glucose. C. Early morning blood insulin levels are elevated above those normally found first thing in the morning. D. Options B and C E. Options A and B

D

Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species? A. a river otter B. a mouse species living in a tropical rain forest C. a mouse species living in a temperate broadleaf forest D. a mouse species living in a desert

D

On completion of stomach digestion of a meal, acid chyme released from the stomach into the duodenum stimulates the S cells and I cells in the duodenal wall to release hormones into the blood that stimulate the pancreas to_____. A. neutralize the acidic mixture in the duodenum B. initiate the emulsification of lipids in the duodenum C. initiate the digestion of carbohydrates and proteins in the duodenum D. options A, B and C, combined

D

Secretin, a hormone released from S cells in the duodenal wall by acidic solutions, stimulates _____. A. the release of dissacharidases from the pancreas B. the release of CCK from I cells in the duodenal wall C. the release of bicarbonate solution from the pancreas D. options B and C, combined

D

The diagnosis of hypertension in adult humans is based on _____. A. the measurement of fatty deposits on the endothelium of arteries B. the measurement of the LDL/HDL ratio in peripheral blood C. a heart rate of over 90 beats per minute D. blood pressure being greater than 140 mm Hg systolic and/or greater than 90 mm Hg diastolic

D

The operation of the sodium-potassium "pump" moves _____. A. sodium and potassium ions into the cell B. sodium and potassium ions out of the cell C. sodium ions into the cell and potassium ions out of the cell D. sodium ions out of the cell and potassium ions into the cell

D

The velocity of blood flow and blood pressure is the lowest in capillaries because _____. A. the capillaries have internal valves that slow the flow of blood B. the diastolic blood pressure is too low to deliver blood to the capillaries at a high flow rate C. the systemic capillaries are supplied by the left ventricle, which has a lower cardiac output than the right ventricle D. the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system

D

Which of the following is an example of negative feedback? A. During birthing contractions, oxytocin (a hormone) is released and acts to stimulate further contractions. B. When a baby is nursing, suckling leads to the production of more milk and a subsequent increase in the secretion of prolactin (a hormone that stimulates lactation). C. After a blood vessel is damaged, signals are released by the damaged tissues that activate platelets in the blood. These activated platelets release chemicals that activate more platelets. D. Low acidic pH in the stomach 1-2 hours after a meal diminishes the release of gastric juice containing hydrochloric acid into the stomach lumen

D

Which of the following is the correct sequence of blood flow in humans? A. left ventricle → aorta → lungs → systemic circulation B. vena cava → right atrium → right ventricle → pulmonary vein C. pulmonary vein → left atrium → left ventricle → pulmonary circuit D. vena cava → right atrium → right ventricle → pulmonary artery

D

A 45-year old man, with many years of autoimmune type 1 diabetes (i.e., his own specific/acquired immune system has destroyed/is still destroying his pancreatic beta cells that secrete insulin), presents complaining of overall weakness and lightheadedness for quite a few weeks. His diabetes has been well controlled on insulin therapy (blood glucose levels between 100-124 mg/dl), but he has noticed increasing episodes of hypoglycemia (low blood glucose levels, <50 mg/dl) without explanation. Morning cortisol levels are very low, while adrenocorticotropic hormone (ACTH) levels are very high. Circulating levels of thyroid-related hormones (TSH, T3 and T4, see Q.13 diagram above) are normal, as are testosterone levels for this man's age. What is the most likely explanation for this recent onset of new symptoms over the last few weeks? A) Expansion of autoimmune destruction of his pancreatic beta cells to now include autoimmune destruction of his ACTH producing cells in the anterior pituitary. B) Chronic stress. C) A recent onset of dysfunction in his ability to synthesize steroid hormones from cholesterol that would diminish circulating levels of both cortisol and testosterone. D) The man has recently developed an anterior pituitary ACTH secreting tumor. E) Expansion of autoimmune destruction of his pancreatic beta cells to now include autoimmune destruction of his adrenal cortex

E

The human kidney is efficient at retaining salt while excreting urea because: A. salt is re-absorbed from nephron filtrate in the proximal tubule during sodium transport-driven uptake of salt, sugar and vitamins B. the high osmolality of the inner kidney medulla permits passive transport of water out of nephron filtrate in the descending loop of Henle C. salt is actively transported out of nephron filtrate in the ascending loop of Henle D. salt is actively transported out of nephron filtrate in the distal tubule E. all of the above

E

When a virus infects cells in the body: A. infected cells will present fragments of the virus on the cell's surface bound to MHC Class II molecules that will attract binding by a cytotoxic T cell B. infected cells will present fragments of the virus on the cell's surface bound to MHC Class I molecules which will attract binding by a helper T cell C. helper T cells activated by binding to viral antigen-presenting, but also viral infected, dendritic cells will amplify the body's cell-mediated immune response by stimulating the proliferation of activated T cells and B cells in the vicinity D. cytotoxic T cell binding to viral infected cells requires CD8 molecule binding E. only (c) and (d) will occur.

E