ATI TEAS 7 — All Questions

Which organ stores and concentrates bile until it is needed?

• a.The gallbladder✓
• b.The pancreas
• c.The liver
• d.The first part of the small intestine

The gallbladder holds bile between meals and releases it when fatty food arrives. The liver produces bile rather than storing it, the pancreas makes digestive enzymes, and the first part of the small intestine is where bile is delivered.

What is peristalsis?

• a.The absorption of water in the large intestine
• b.Wavelike muscle contractions that move food along✓
• c.The chemical breakdown of nutrients by enzymes
• d.The release of hormones that signal hunger

Peristalsis is the rhythmic squeezing of smooth muscle that propels contents through the digestive tract. Enzyme action, water absorption, and hunger signaling are separate processes that do not describe this movement.

What is the main function of the large intestine?

• a.Absorbing water and forming solid waste✓
• b.Absorbing the majority of amino acids
• c.Producing most digestive enzymes
• d.Secreting acid to kill swallowed bacteria

The large intestine reclaims water and electrolytes, compacting the remaining material into feces. Most enzymes come from the pancreas, nutrient absorption happens in the small intestine, and acid secretion occurs in the stomach.

How do villi and microvilli improve the function of the small intestine?

• a.They neutralize acid arriving from the stomach
• b.They secrete bile into the intestinal lumen
• c.They slow food down so digestion lasts longer
• d.They greatly increase the surface area for absorption✓

These finger-like projections multiply the absorptive surface many times over, so more nutrients cross into the blood and lymph. Bile comes from the liver, and neither slowing transit nor neutralizing acid is what the projections themselves accomplish.

Which organ produces digestive enzymes and also releases insulin and glucagon?

• a.The pancreas✓
• b.The spleen
• c.The thymus gland
• d.The liver

The pancreas has both roles: an exocrine portion releasing enzymes into the duodenum and islet cells releasing insulin and glucagon into the blood. The spleen filters blood, the liver processes nutrients and makes bile, and the thymus matures T cells.

What is the functional unit of the kidney?

• a.The nephron✓
• b.The renal pelvis
• c.The ureter
• d.The alveolus

Each kidney contains about a million nephrons, and every one filters blood and forms urine. The ureter drains urine away, the renal pelvis collects it, and the alveolus belongs to the lungs.

In which part of the nephron does filtration of blood first occur?

• a.The distal tubule
• b.The collecting duct
• c.The glomerulus✓
• d.The loop of Henle

Blood pressure forces water and small solutes out of the glomerular capillaries into the surrounding capsule, which is the first step. The loop of Henle, distal tubule, and collecting duct then modify that filtrate by reabsorption and secretion.

Which tube carries urine from the kidney to the urinary bladder?

• a.The ureter✓
• b.The urethra
• c.The renal artery
• d.The vas deferens

The ureter runs from each kidney down to the bladder. The urethra carries urine from the bladder out of the body, the renal artery delivers blood into the kidney, and the vas deferens is part of the male reproductive tract.

Antidiuretic hormone acts on the kidney to produce what effect?

• a.More dilute urine in larger amounts
• b.More glucose returned to the blood
• c.More sodium excreted in the urine
• d.More water reabsorbed and less urine✓

Antidiuretic hormone makes the collecting ducts permeable to water, so water returns to the blood and urine volume falls. Aldosterone is the hormone that governs sodium handling, and glucose reabsorption is not under this hormone's control.

Besides removing waste, which of these is a function of the kidneys?

• a.Producing bile for the digestion of fats
• b.Producing antibodies against infection
• c.Secreting insulin to lower blood glucose
• d.Regulating the pH of the blood✓

The kidneys adjust bicarbonate and hydrogen ion excretion, which is a major control on blood pH. Bile comes from the liver, insulin from the pancreas, and antibodies from plasma cells of the immune system.

Which waste product in urine comes mainly from the breakdown of proteins?

• a.Bilirubin
• b.Carbon dioxide
• c.Lactic acid
• d.Urea✓

Amino acids are deaminated in the liver, and the resulting ammonia is converted to urea for excretion by the kidneys. Bilirubin comes from broken-down hemoglobin, lactic acid from anaerobic metabolism in muscle, and carbon dioxide is exhaled rather than excreted as a urinary waste.

Which term describes the body's tendency to maintain a stable internal environment?

• a.Mitotic cell division
• b.Metabolism
• c.Homeostasis✓
• d.Diffusion

Homeostasis is the regulated stability of conditions such as temperature, pH, and glucose. Metabolism is the sum of chemical reactions, diffusion is one transport mechanism, and mitotic cell division produces new body cells.

What is the primary function of the myelin sheath on a neuron?

• a.It anchors the neuron to surrounding connective tissue
• b.It receives incoming signals from neighboring neurons
• c.It speeds the conduction of the nerve impulse✓
• d.It manufactures the neurotransmitters released at the synapse

Myelin insulates the axon so the impulse jumps between gaps and travels far faster than it would on a bare axon. Neurotransmitters are made in the cell body and terminals, dendrites receive signals, and glial cells rather than myelin provide structural support.

Which division of the nervous system prepares the body for 'fight or flight'?

• a.The somatic division
• b.The sympathetic division✓
• c.The parasympathetic division
• d.The enteric division

Sympathetic activity raises heart rate, dilates airways, and shunts blood to skeletal muscle. The parasympathetic division does the opposite by promoting rest and digestion, the somatic division controls voluntary movement, and the enteric division regulates the gut.

Which part of the brain coordinates balance and smooth voluntary movement?

• a.The occipital lobe of the cerebrum
• b.The medulla oblongata
• c.The hypothalamus
• d.The cerebellum✓

The cerebellum fine-tunes posture, balance, and the timing of movement. The medulla governs automatic functions such as heart rate and breathing, the hypothalamus regulates temperature and hunger, and the occipital lobe processes vision.

Damage to the medulla oblongata is life-threatening mainly because it controls:

• a.The sense of balance while walking
• b.The interpretation of visual information
• c.The formation of new long-term memories
• d.Heart rate and the rhythm of breathing✓

The medulla contains the cardiac and respiratory centers, so injury there can stop the heartbeat or breathing. Memory is a function of the hippocampus and cortex, vision belongs to the occipital lobe, and balance is handled by the cerebellum and inner ear.

What is a synapse?

• a.The branching region that receives incoming signals
• b.The junction where a signal passes between neurons✓
• c.The insulating layer wrapped around a long axon
• d.The portion of the neuron that contains the nucleus

A synapse is the gap where one neuron communicates with the next, usually by releasing a neurotransmitter. The insulating layer is myelin, the receiving branches are dendrites, and the region holding the nucleus is the cell body.

In a simple reflex such as the knee-jerk, where is the response coordinated?

• a.In the spinal cord✓
• b.In the cerebellum
• c.In the pituitary gland
• d.In the frontal lobe of the cerebrum

A reflex arc travels from sensory neuron to spinal cord to motor neuron, which is why the response happens before the brain interprets it. The cerebrum and cerebellum may register the event afterward, and the pituitary is an endocrine gland with no role in reflexes.

Which structure connects a skeletal muscle to a bone?

• a.A synovial membrane
• b.A ligament
• c.Cartilage
• d.A tendon✓

Tendons are dense connective tissue joining muscle to bone. Ligaments join one bone to another, cartilage cushions joint surfaces, and the synovial membrane secretes lubricating fluid inside a joint capsule.

Which two protein filaments slide past each other to shorten a muscle fiber?

• a.Actin and myosin✓
• b.Keratin and albumin
• c.Collagen and elastin
• d.Fibrin and thrombin

The sliding filament model describes myosin heads pulling on actin filaments to shorten the sarcomere. Collagen and elastin are structural proteins of connective tissue, keratin and albumin are unrelated to contraction, and fibrin and thrombin belong to blood clotting.

Skeletal muscle is best described as:

• a.Voluntary and without any striations
• b.Involuntary and striated in appearance
• c.Voluntary and striated in appearance✓
• d.Involuntary and without striations

Skeletal muscle is under conscious control and shows a banded pattern under the microscope. Cardiac muscle is striated but involuntary, and smooth muscle is both involuntary and unstriated, so the other combinations describe those tissues instead.

When the biceps contracts to bend the elbow, what does the triceps do?

• a.It detaches from the bone to allow movement
• b.It contracts with equal force at the same time
• c.It contracts first and then shortens further
• d.It relaxes and lengthens as the opposing muscle✓

Muscles work in antagonistic pairs: one shortens while its partner relaxes, because muscles can only pull. Simultaneous equal contraction would lock the joint, and muscles never detach from bone during normal movement.

Approximately how many bones are in the adult human skeleton?

• a.150
• b.300
• c.450
• d.206✓

An adult skeleton has about 206 bones. Infants are born with roughly 300, many of which fuse during growth, so 300 describes a newborn rather than an adult, and 150 and 450 are far from either figure.

Which tissue inside certain bones produces red and white blood cells?

• a.Red bone marrow✓
• b.Articular cartilage
• c.Compact bone tissue
• d.The periosteum

Red marrow is the site of hematopoiesis, forming red cells, white cells, and platelets. Compact bone provides strength, articular cartilage covers joint surfaces, and the periosteum is the membrane wrapping the outside of a bone.

The knee and the elbow are examples of which type of joint?

• a.Immovable fibrous joints
• b.Hinge joints✓
• c.Pivot joints
• d.Ball-and-socket joints

A hinge joint permits bending and straightening in one plane, which is how the knee and elbow move. Ball-and-socket joints such as the hip rotate in many directions, pivot joints allow rotation around an axis, and fibrous joints such as skull sutures barely move.

Besides support and movement, which mineral do bones store and release for the body?

• a.Zinc
• b.Calcium✓
• c.Iron
• d.Iodine

Bone is the body's calcium reservoir, releasing it when blood levels fall. Iodine is stored in the thyroid, most iron is held in hemoglobin and the liver, and zinc is not stockpiled in the skeleton.

Which cells break down bone tissue so that minerals can be released into the blood?

• a.Erythrocytes
• b.Osteoblasts
• c.Chondrocytes
• d.Osteoclasts✓

Osteoclasts resorb bone matrix, while osteoblasts do the opposite by depositing new bone. Chondrocytes maintain cartilage and erythrocytes are red blood cells, so neither remodels bone.

Which gland is often called the 'master gland' because it directs several other endocrine glands?

• a.The adrenal gland
• b.The pineal gland
• c.The pituitary gland✓
• d.The thyroid gland

The pituitary releases hormones that regulate the thyroid, adrenal cortex, and gonads, though it is itself directed by the hypothalamus. The thyroid and adrenal glands are among the targets it controls, and the pineal gland mainly secretes melatonin.

Which hormone raises blood glucose when levels fall between meals?

• a.Aldosterone
• b.Glucagon✓
• c.Calcitonin
• d.Insulin

Glucagon, released by pancreatic alpha cells, signals the liver to break down glycogen and release glucose. Insulin does the opposite by lowering blood glucose, calcitonin lowers blood calcium, and aldosterone regulates sodium.

The thyroid gland requires which dietary element to make its hormones?

• a.Phosphorus
• b.Iodine✓
• c.Magnesium
• d.Calcium

Thyroid hormones are built around iodine atoms, which is why deficiency can enlarge the gland. Calcium, magnesium, and phosphorus have important roles elsewhere but are not incorporated into thyroid hormone.

Most hormone systems in the body are controlled by which kind of regulation?

• a.Positive feedback
• b.Random secretion
• c.Negative feedback✓
• d.Continuous maximum output

In negative feedback, the response reduces the original stimulus, holding the variable near a set point. Positive feedback amplifies a change and is rare, used in events such as labor contractions, while random or maximal secretion would make regulation impossible.

Which gland releases epinephrine during a stressful event?

• a.The thymus
• b.The adrenal gland✓
• c.The parathyroid gland
• d.The salivary gland

The adrenal medulla secretes epinephrine, raising heart rate and blood glucose. The thymus matures T cells, the parathyroid glands regulate calcium, and salivary glands produce saliva.

Which cells produce antibodies during an adaptive immune response?

• a.Red blood cells
• b.Cytotoxic T lymphocytes
• c.B lymphocytes✓
• d.Platelets

B lymphocytes mature into plasma cells that secrete antibodies against a specific antigen. Cytotoxic T cells kill infected cells directly rather than secreting antibodies, and red cells and platelets have no role in antibody production.

What is an antigen?

• a.A protein the body makes to neutralize a pathogen
• b.A cell that engulfs and digests invading bacteria
• c.A substance recognized as foreign by the immune system✓
• d.A chemical that raises the body's temperature

An antigen is the foreign marker the immune system detects and responds to. The protein made to neutralize it is an antibody, the engulfing cell is a phagocyte, and a temperature-raising chemical is a pyrogen.

How does a vaccine protect a person from a disease?

• a.It permanently raises the body's core temperature
• b.It supplies antibodies borrowed from another person
• c.It prompts the immune system to form memory cells✓
• d.It kills any pathogen already present in the blood

A vaccine exposes the immune system to a harmless form of an antigen so memory cells can respond quickly to a later infection. Receiving ready-made antibodies is passive immunization rather than vaccination, and vaccines neither sterilize the blood nor change body temperature.

Which response is part of nonspecific, innate immunity rather than adaptive immunity?

• a.Recognizing a previously encountered antigen
• b.Inflammation at the site of a wound✓
• c.Producing antibodies against a specific virus
• d.Forming memory cells after an infection

Inflammation occurs the same way no matter what the invader is, which makes it innate. Antibody production, memory cell formation, and antigen recognition all target a particular pathogen and therefore belong to adaptive immunity.

Which layer of the skin contains blood vessels, nerve endings, sweat glands, and hair follicles?

• a.The stratum corneum
• b.The dermis✓
• c.The epidermis
• d.The subcutaneous fat layer

The dermis is the thick middle layer holding vessels, nerves, glands, and follicles. The epidermis and its outermost stratum corneum have no blood supply of their own, and the subcutaneous layer beneath is mostly fat and loose connective tissue.

What is the main protective role of melanin in the skin?

• a.It insulates the body against heat loss
• b.It absorbs ultraviolet radiation from sunlight✓
• c.It fights bacteria that land on the skin
• d.It waterproofs the surface of the skin

Melanin pigment absorbs ultraviolet light and limits damage to the DNA of skin cells. Waterproofing comes largely from keratin and oils, insulation comes from subcutaneous fat, and antibacterial defense comes from the skin's acidic secretions.

In a typical pregnancy, where does fertilization of the egg normally occur?

• a.In the fallopian tube✓
• b.In the uterus
• c.In the ovary
• d.In the cervix

Sperm normally meet the egg in the fallopian tube, and the fertilized egg then travels to the uterus to implant. The ovary releases the egg, the uterus receives the embryo afterward, and the cervix is the passage into the uterus.

The cell membrane is described as selectively permeable. What does this mean?

• a.It blocks every substance from entering or leaving the cell
• b.It allows anything dissolved in water to pass freely
• c.It allows some substances to cross while restricting others✓
• d.It dissolves whenever the cell is placed into water

A selectively permeable membrane controls which molecules cross, letting small nonpolar substances pass while regulating ions and large molecules. Blocking everything would starve the cell, free passage of all solutes would eliminate control, and the membrane does not dissolve in water.

Which organelle assembles amino acids into proteins?

• a.The ribosome✓
• b.The Golgi apparatus
• c.The lysosome
• d.The nucleolus

Ribosomes read messenger RNA and link amino acids into polypeptide chains. The Golgi apparatus modifies and packages proteins after they are made, lysosomes digest waste, and the nucleolus builds ribosome subunits rather than proteins.

Which structure is found in a plant cell but NOT in an animal cell?

• a.A cell membrane
• b.A nucleus
• c.Mitochondria
• d.A cell wall✓

Plant cells are enclosed by a rigid cellulose wall outside the membrane, which animal cells lack. Membranes, nuclei, and mitochondria are present in both types of eukaryotic cell.

Which organelle contains digestive enzymes that break down worn-out cell parts?

• a.The lysosome✓
• b.The rough endoplasmic reticulum
• c.The centriole
• d.The Golgi apparatus

Lysosomes hold hydrolytic enzymes that dismantle damaged organelles and engulfed material. The rough endoplasmic reticulum makes proteins, centrioles organize the spindle during division, and the Golgi apparatus sorts and ships products.

Which macromolecule is built from a chain of amino acids?

• a.A lipid
• b.A carbohydrate
• c.A nucleic acid
• d.A protein✓

Amino acids joined by peptide bonds form proteins. Carbohydrates are chains of sugars, lipids are built from fatty acids and glycerol, and nucleic acids are chains of nucleotides.

A red blood cell placed in pure distilled water will most likely:

• a.Swell as water moves into the cell✓
• b.Shrink as water leaves the cell
• c.Lose its nucleus into the water
• d.Stay exactly the same size

Distilled water is hypotonic to the cell's interior, so water moves in by osmosis and the cell swells and may burst. Shrinking happens in a hypertonic solution, and mature red blood cells have no nucleus to lose.

Which transport process requires the cell to spend energy?

• a.Active transport against a gradient✓
• b.Facilitated diffusion through a channel
• c.Osmosis of water across a membrane
• d.Simple diffusion of small molecules

Moving a substance from lower to higher concentration works against the gradient and requires ATP. Simple diffusion, osmosis, and facilitated diffusion all follow the gradient and are therefore passive.

In DNA, the base adenine always pairs with which other base?

• a.Cytosine
• b.Uracil
• c.Guanine
• d.Thymine✓

Complementary base pairing in DNA joins adenine to thymine and guanine to cytosine. Uracil replaces thymine only in RNA, so it is not a DNA pairing partner.

Which statement correctly distinguishes RNA from DNA?

• a.RNA contains no sugar while DNA contains ribose
• b.RNA is double-stranded while DNA is single-stranded
• c.RNA contains uracil while DNA contains thymine✓
• d.RNA is found only outside cells while DNA is inside

Uracil replaces thymine in RNA, and RNA also carries ribose rather than deoxyribose. RNA is typically single-stranded while DNA is a double helix, RNA is found inside cells, and both molecules contain a sugar.

What is the result of meiosis in humans?

• a.Two identical cells with 46 chromosomes each
• b.Two cells that are genetically identical clones
• c.Four cells with 23 chromosomes each✓
• d.One cell with 92 chromosomes

Meiosis halves the chromosome number and produces four genetically varied gametes with 23 chromosomes. Mitosis is what yields two identical 46-chromosome cells, and no normal human cell division produces a 92-chromosome cell.

An organism's observable physical traits are called its:

• a.Genotype
• b.Allele
• c.Karyotype
• d.Phenotype✓

Phenotype is what can be observed, such as eye color or height. Genotype is the underlying combination of alleles, a karyotype is a picture of the chromosomes, and an allele is one version of a single gene.