Structure and Function of the Human Body

Which of the following statements about the digestive system is correct?

1. The esophagus has many secretory glands for digestive juices distributed in it, and digestion is carried out by the digestive juice secreted from them.
2. Reducing the contents of the digestive tract into smaller pieces through chewing and the movement of the digestive tract is called chemical digestion.
3. The digestive tract is a tube running from the oral cavity to the anus, about 9 m long in total in an average adult.
4. The inner wall mucosa of the large intestine has villi, which allow efficient absorption of nutrients.

Which of the following statements about the oral cavity and saliva is incorrect?

1. Ptyalin, contained in saliva, is a digestive enzyme that breaks down protein into amino acids.
2. Saliva keeps the pH inside the oral cavity close to neutral, preventing tooth decay from acid.
3. The surface of the tooth crown is covered with enamel, the hardest part of the body.
4. The surface of the tongue has countless small projections called papillae, on which taste buds that detect taste are distributed.

Which of the following statements about the stomach is correct?

1. The time food contents stay in the stomach is relatively short for a food high in lipids.
2. Pepsin, contained in gastric juice, is an enzyme that breaks down lipids.
3. Pepsinogen is converted by gastric acid into pepsin, an enzyme that digests protein.
4. A component contained in gastric mucus plays an important role in the absorption of vitamin K in the large intestine.

Which of the following statements about the small intestine is incorrect?

1. Except for the upper part of the duodenum, the inner wall of the small intestine is smooth, with no folds or villi seen.
2. The duodenum is a C-shaped, curved part about 25 cm long continuing from the stomach, and the openings of the pancreatic duct and bile duct are located at the curved section.
3. It is a tubular organ 6 to 7 m long in total, divided into three parts: the duodenum, jejunum, and ileum.
4. Of the part of the small intestine continuing from the duodenum, roughly the upper 40% is the jejunum and the remaining approximately 60% is the ileum.

Which of the following statements about the pancreas is correct?

1. The pancreas is a digestive gland that supplies only the enzymes that digest carbohydrates and protein, and is thought not to be responsible for supplying an enzyme that digests lipids.
2. The pancreas is a digestive gland, and also an endocrine gland that secretes hormones regulating blood glucose (insulin and glucagon) and the like into the blood.
3. Trypsin in pancreatic juice is secreted already in its active form, and breaks down protein partially digested in the stomach (peptone) all the way to amino acids.
4. Pancreatic juice is strongly acidic, has the function of further breaking down contents that have become acidic in the stomach, and is secreted into the duodenum.

Which of the following statements about the gallbladder and bile is incorrect?

1. Most of the bile salts released into the intestine are reabsorbed in the small intestine and returned to the liver.
2. The gallbladder is an organ that concentrates and stores bile produced in the liver, and contracts to send bile into the intestine when contents enter the duodenum.
3. Bilirubin (bile pigment), contained in bile, is a waste product produced from the breakdown of white blood cells.
4. Bile salts, contained in bile, make the digestion of lipids easier and also assist in the absorption of fat-soluble vitamins.

Which of the following statements about the liver is correct?

1. Ammonia, produced when amino acids are broken down and the like, is metabolized in the liver into uric acid and excreted from the kidneys.
2. The liver is a storage organ only for fat-soluble vitamins, and water-soluble vitamins are not stored there.
3. Glucose absorbed in the small intestine is carried by the blood to the liver and stored as glycogen.
4. Alcohol is first metabolized in the liver into acetic acid, and then further metabolized into acetaldehyde.

Which of the following statements about the large intestine is incorrect?

1. Ordinarily, most of the components of feces are food residue, with water accounting for only about 5%.
2. It is a tubular organ consisting of the cecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.
3. Intestinal bacteria in the large intestine also produce substances such as vitamin K, needed for blood coagulation and calcium fixation in bone.
4. In the large intestine, water and electrolytes such as sodium, potassium, and phosphate are absorbed, forming solid feces.

Which of the following correctly matches a digestive enzyme with its function?

1. Lipase — a digestive enzyme contained in saliva that breaks down starch into dextrin and maltose
2. Maltase — breaks down carbohydrates into monosaccharides (glucose, galactose, fructose)
3. Ptyalin — a digestive enzyme, contained in pancreatic juice, that acts to break down lipids
4. Erepsin — a digestive enzyme on the intestinal mucosa that breaks down carbohydrates into monosaccharides

Which of the following statements about the absorption of nutrients in the small intestine is incorrect?

1. Carbohydrates and protein are broken down by the action of digestive enzymes into monosaccharides and amino acids respectively, and absorbed.
2. When lipids become chylomicron particles, fat-soluble vitamins are also taken up together.
3. After being absorbed by the epithelial cells of the small intestine's mucosa, lipids are carried throughout the body in their unchanged form, without being re-formed.
4. Lipids (triglycerides) are broken down by the action of a digestive enzyme (lipase).

Which of the following statements about the respiratory system is correct?

1. The larynx is a cylindrical organ surrounded by cartilage between the pharynx and the trachea, and also plays a role as the organ of voice production.
2. Of the airway, the part from the pharynx to the larynx is called the lower airway, and the part from the trachea through the bronchi to the lungs is called the upper airway.
3. Nasal mucus contains pepsin, serving as one of the airway's defense mechanisms.
4. The pharynx belongs only to the airway, and does not belong to the digestive tract.

Which of the following statements about the lungs is incorrect?

1. Across the alveolar wall, carbon dioxide diffuses from the blood into the alveolar air, and in exchange oxygen is taken up into red blood cells in the blood.
2. The lungs themselves have muscle tissue that moves them, and they expand and contract on their own to carry out respiratory movement.
3. The tissue surrounding and supporting the alveoli and capillaries is called the interstitium.
4. Inside the lungs, the bronchi branch finely, and the spherical sac-like part at their terminal end is called the alveolus.

Which of the following statements about the heart is correct?

1. The right side of the heart (right atrium, right ventricle) sends blood gathered from throughout the body out to the lungs.
2. Blood that has undergone gas exchange in the lungs enters the right side of the heart, from which it is sent out to the whole body.
3. The interior of the heart is divided into four cavities: the upper left and right ventricles, and the lower left and right atria.
4. The ventricles gather blood and send it to the atria, and the atria pump the blood out.

Which of the following statements about the vascular system is incorrect?

1. A blood vessel carrying blood pumped out from the heart is called an artery, and one carrying blood returning to the heart is called a vein.
2. Most of the capillaries running through the digestive tract wall gather into a blood vessel called the portal vein and enter the kidneys.
3. In veins running through the limbs, venous valves are well developed at regular intervals, preventing the backflow of blood.
4. Because the pressure placed on a vein is relatively low, its vessel wall is thinner than that of an artery.

Which of the following statements about plasma is correct?

1. Most of albumin serves as an antibody that specifically recognizes foreign substances in immune responses.
2. Albumin forms complexes with hormones, medicine ingredients, and the like, making them less susceptible to metabolism and excretion when carried by the blood.
3. Blood viscosity is mainly determined by the amount of lipid in the blood, and the water content of plasma and the amount of red blood cells have almost no effect.
4. Plasma is composed of about 50% water, with the majority of the remainder being protein.

Which of the following statements about red blood cells is incorrect?

1. A red blood cell is a disk-shaped cell with a depressed center, accounting for about 40% of the total blood volume.
2. Hemoglobin is a protein bound to iron, which binds with oxygen molecules where oxygen levels are high.
3. Red blood cells are produced in the bone marrow.
4. Most carbon dioxide binds with hemoglobin and is carried from peripheral tissues to the lungs.

Which of the following statements about white blood cells is correct?

1. Lymphocytes account for about one-third of white blood cells, and include T lymphocytes, which recognize foreign substances such as bacteria and viruses, and B lymphocytes, which produce antibodies against them.
2. Monocytes are the most numerous type of white blood cell, accounting for about 60% of them, and pass through blood vessel walls into tissue, taking in and breaking down bacteria, viruses, and the like by phagocytosis.
3. When infection or inflammation occurs, the total number of white blood cells increases, but the proportion of each type never changes.
4. Neutrophils account for only about 5% of white blood cells, few in number but the largest, and are called macrophages in tissue, having strong phagocytic activity.

Which of the following statements about platelets and the mechanism of hemostasis is incorrect?

1. Fibrin, a type of plasma protein, polymerizes at the wound to become fibrous fibrinogen.
2. Red blood cells, platelets, and the like become entangled in fibrin fibers, forming a blood clot that seals the wound.
3. A damaged blood vessel reduces blood flow by contracting its wall, preventing a large amount of blood from flowing out.
4. Platelets adhere and aggregate at the site of injury, covering the wound.

Which of the following statements about the spleen is correct?

1. The spleen is a fist-sized, sponge-like organ located in the upper left abdomen behind the stomach.
2. The spleen's main function is to filter out and process aged white blood cells from the blood flowing through it.
3. The spleen has no lymphatic tissue and plays no part in immune responses.
4. Red blood cells that have aged and lost flexibility slip through the spleen's mesh-like structure and return to the general circulation.

Which of the following statements about the lymphatic system is incorrect?

1. Lymphocytes and macrophages are densely packed inside a lymph node, and bacteria, viruses, and the like carried there by lymph fluid are eliminated there through immune reactions.
2. Lymph fluid is composed of almost the same components as plasma, but has less protein and contains lymphocytes.
3. Lymphatic vessels merge with one another and gradually become thicker, ultimately connecting to an artery beneath the collarbone.
4. The lymphatic system has no organ that acts as a pump the way the heart does, and the flow of lymph fluid is mainly driven by the contraction of skeletal muscle.

Which of the following statements about the structure of the kidney is correct?

1. The outside of the glomerulus is enclosed by the sac-like Bowman's capsule, and together they are called the renal corpuscle.
2. Reabsorption of waste products takes place in the renal corpuscle, and filtration of the blood takes place in the renal tubule.
3. The kidneys are a pair of broad-bean-shaped organs located above the diaphragm, on either side of the spine.
4. The renal tubule and the ureter together make up the nephron, the kidney's basic functional unit.

Which of the following statements about the production of urine in the kidney is incorrect?

1. At the renal tubule, nutrients such as glucose and amino acids in the primary urine, and water and electrolytes needed to maintain the blood, are reabsorbed.
2. Plasma components other than blood cells and protein are also filtered at the renal corpuscle.
3. Urine is produced by the filtration of blood, but microorganisms such as bacteria are always present even in a healthy state.
4. At the renal corpuscle, waste products in the blood, such as urea, are filtered and enter the renal tubule as primary urine.

Which of the following statements about the kidney is correct?

1. In the kidney, the regulation of excretion is carried out for water and electrolytes, particularly calcium.
2. One-half to one-third of the blood pumped out by the heart flows through the kidneys.
3. Vitamin K, whether ingested from food or biosynthesized in the body, is converted into its active form in the kidney.
4. The kidney also has a function as an endocrine gland, secreting a hormone that promotes the production of red blood cells in the bone marrow.

Which of the following statements about the adrenal gland is incorrect?

1. Aldosterone plays a role in regulating the excretion of electrolytes and water.
2. In the adrenal cortex, adrenaline and noradrenaline, which act on the autonomic nervous system, are produced and secreted.
3. Aldosterone, one of the adrenocortical hormones, has the action of retaining salt and water in the body and promoting the excretion of potassium.
4. The adrenal glands are attached to the top of each of the left and right kidneys, and consist of two layers, the cortex and the medulla.

Which of the following statements about the urinary tract (bladder, urethra) is correct?

1. Because men have a short urethra, infection can readily spread to the bladder when bacteria and the like invade.
2. When the bladder sphincter muscle at the bladder's outlet relaxes, the detrusor muscle of the bladder wall contracts at the same time, pushing urine out into the urethra.
3. In women, the prostate gland surrounds the urethra directly below the bladder, and can enlarge with age.
4. During urination, the bladder sphincter muscle at the bladder's outlet contracts at the same time as the detrusor muscle of the bladder wall relaxes.

Which of the following statements about the eye is correct?

1. Blood vessels run through the transparent cornea and lens, from which nutrients and oxygen are supplied.
2. The space between the retina and the lens is filled with a transparent, jelly-like tissue called the aqueous humor.
3. The space between the cornea and the lens is filled with tissue fluid (aqueous humor), producing a constant pressure inside the eye (intraocular pressure).
4. The iris lies in front of the lens, and adjusts near and far focus by changing the lens's thickness.

Which of the following statements about the eye is incorrect?

1. Vitamin A is essential to the reaction by which the photoreceptor cells that respond sensitively even to faint light sense light, and a deficiency causes reduced night vision (night blindness).
2. The lens becomes flatter when viewing a near object, and rounder and thicker when viewing a distant object.
3. Through contraction and relaxation of the ciliary body, the lens becomes rounder and thicker when viewing a near object, and flatter when viewing a distant object.
4. Photoreceptor cells that receive light are densely packed in the retina, and the retina's nerve fibers bundle together at the back of the eyeball to form the optic nerve.

Which of the following statements about the eyelid, conjunctiva, and lacrimal apparatus is correct?

1. In conjunctival congestion, the white of the eye turns red, but the underside of the eyelid does not turn red and remains white.
2. Because the eyelid's subcutaneous tissue is thick and sturdy, it rarely suffers internal bleeding or lacerations even from injury.
3. Tear fluid contains lysozyme, immunoglobulin, and the like, and works to protect the cornea and conjunctiva from infection.
4. The lacrimal gland is a secretory gland on the underside of the lower eyelid, producing tear fluid from lymph fluid as its material.

Which of the following statements about the nose is incorrect?

1. When an odor molecule stimulates the olfactory cells in the mucosa of the upper nasal cavity, the stimulus is conveyed to the brain's olfactory center.
2. The front part of the nasal septum is prone to injury and nosebleeds because it has an abundant distribution of capillaries in addition to thin mucosa.
3. The sense of smell is extremely sensitive but readily adapts, so that continuing to smell the same odor gradually leads to no longer perceiving it.
4. Because the tube connecting the paranasal sinuses and the nasal cavity is thick and wide, swelling of the nasal cavity's mucosa never causes inflammation in the paranasal sinuses.

Which of the following statements about the ear is correct?

1. The inner ear consists of two parts: the vestibule, the hearing organ that senses sound, and the cochlea, the balance organ that senses body balance.
2. In small children, the Eustachian tube is thick and short with a nearly horizontal course, so viruses and bacteria readily invade from the nasal cavity, causing infection.
3. The inside of the cochlea is filled with air, and the mechanism by which sound is sensed is that vibration conveyed from the auditory ossicles directly stimulates the auditory nerve.
4. The outer ear consists of three parts—the eardrum, the tympanic cavity, and the auditory ossicles and Eustachian tube—with the auditory ossicles amplifying the eardrum's vibration and conducting it to the inner ear.

Which of the following statements about the types of white blood cells and their roles is correct?

1. Lymphocytes account for only about 5% of white blood cells, few in number but the largest, with strong phagocytic activity, and are cells called macrophages in tissue.
2. Neutrophils can pass through blood vessel walls into tissue, migrating to and gathering at a site of infection, and taking in and breaking down bacteria, viruses, and the like by phagocytosis.
3. Among white blood cells, some are involved in infection by bacteria, viruses, and the like, but none is involved in allergy.
4. Monocytes proliferate in lymphatic tissue such as the lymph nodes and spleen, recognizing foreign substances such as bacteria and viruses and also producing antibodies (immunoglobulins) against them.

Which of the following statements about the central nervous system is correct?

1. The cardiac center, which regulates heart rate, and the respiratory center, which regulates breathing, are located in the spinal cord.
2. The function by which the brain's capillaries work to protect the interstitial fluid environment of the central nervous system from fluctuations in the composition of the blood is called the blood-brain barrier.
3. The brain's oxygen consumption is about 25% of the body's total, and its glucose consumption is about 20% of the body's total.
4. A spinal reflex means that all stimuli from the periphery are processed via the brain.

Which of the following statements about the blood-brain barrier is incorrect?

1. In the brain, the volume of blood circulation is about 15% of cardiac output.
2. Large molecules such as proteins, and even small molecules if ionized, have difficulty moving from the blood into the brain's tissue.
3. The brain's blood vessels have higher selectivity regarding the passage of substances than peripheral vessels.
4. In children, because the blood-brain barrier is developed, a medicine's ingredients that have entered the circulating blood have difficulty reaching brain tissue.

Which of the following statements about the skin is incorrect?

1. The arrector pili muscle contracts in response to stimuli such as changes in temperature or emotion, causing the pilomotor reflex (so-called 'goose bumps'), in which the pores rise up.
2. Melanin pigment is produced by melanin-producing cells (melanocytes) in the bottom layer of the epidermis.
3. The skin has a three-layer structure of epidermis, dermis, and subcutaneous tissue.
4. Apocrine glands (body odor glands) are distributed throughout the body, including areas without hair roots such as the palms.

Which of the following statements about the action of the autonomic nervous system on effector organs is correct?

1. When the sympathetic nervous system becomes active, the pupil dilates.
2. When the parasympathetic nervous system becomes active, the pupil dilates.
3. When the parasympathetic nervous system becomes active, a small amount of viscous saliva is secreted.
4. When the sympathetic nervous system becomes active, salivation increases.

Which of the following statements about the action of the autonomic nervous system on the heart and peripheral blood vessels is incorrect?

1. When the parasympathetic nervous system becomes active, heart rate decreases.
2. When the parasympathetic nervous system becomes active, peripheral blood vessels dilate and blood pressure falls.
3. When the sympathetic nervous system becomes active, peripheral blood vessels dilate and blood pressure falls.
4. When the sympathetic nervous system becomes active, heart rate increases.

Which of the following statements about the action of the autonomic nervous system on the trachea, bronchi, and stomach is correct?

1. When the sympathetic nervous system becomes active, gastric juice secretion increases.
2. When the parasympathetic nervous system becomes active, the trachea and bronchi dilate.
3. When the sympathetic nervous system becomes active, the trachea and bronchi dilate.
4. When the parasympathetic nervous system becomes active, the stomach's blood vessels constrict.

Which of the following statements about the action of the autonomic nervous system on the intestine and liver is incorrect?

1. When the sympathetic nervous system becomes active, glycogen is broken down in the liver and glucose is released.
2. When the sympathetic nervous system becomes active, intestinal motility increases.
3. When the parasympathetic nervous system becomes active, intestinal motility increases.
4. When the parasympathetic nervous system becomes active, glycogen synthesis takes place in the liver.

Which of the following statements about the action of the autonomic nervous system on the bladder and skin is correct?

1. When the sympathetic nervous system becomes active, the detrusor muscle relaxes and urination is suppressed.
2. When the parasympathetic nervous system becomes active, the detrusor muscle relaxes and urination is promoted.
3. When the parasympathetic nervous system becomes active, the arrector pili muscle on the body's surface contracts.
4. When the sympathetic nervous system becomes active, the detrusor muscle contracts and urination is promoted.

Which of the following statements about the autonomic nervous system is incorrect?

1. Effector organs are governed by two nervous systems, the sympathetic and the parasympathetic, which ordinarily work in opposition to each other.
2. The neurotransmitter released from the ends of the sympathetic nervous system's postganglionic fibers is noradrenaline.
3. When the parasympathetic nervous system becomes active, sweating from the sweat glands increases.
4. At the ends of the sympathetic nerve fibers innervating the sweat glands, acetylcholine is exceptionally released as the transmitter.