ATI Science Pretest Topics

Parathyroid hormone (PTH)

Produced in parathyroid; secreted when plasma calcium levels are low. Directly activates osteoclasts, causing reabsorption of calcium from bones. Also increases plasma calcium levels by inhibiting the kidneys’ ability to transfer calcium ions to urine.

Endocrine response speed

Because blood flows from gland to target organ, it takes longer for hormones to cause a response than it takes neurons of the nervous system.

Endocrine glands

Set of organs that release hormones directly into the circulatory system. Ductless glands.

Small intestine

Approximately 18 ft long. Large surface area due to villi and microvilli. Contains the duodenum, ileum, and jejunum.

Temperature sensors (thermoreceptors)

Located in both the hypothalamus and skin. Provide information to the hypothalamus, which acts as the body’s thermostat.

Electrons in outermost shell

Highest energy electrons and are most easily transferred.

Volumetric pipettes

High precision.

Nurses tape

Measures girth.

Graduated pipettes

Measure approximately 0.1–25 mL of liquids.

Surveyor’s wheel

Measures long nonlinear distances.

0.0008 g NaCl

Equivalent to 0.8 mg.

231 μL blood

Measured with a micropipette.

2 square blocks distance

Measured with a surveyor’s wheel.

External secretion

Pancreatic amylase that digests starch in the small intestine.

Pancreas

Special organ because it secretes both enzymes and hormones.

Nonsteroid hormones

Water-soluble hormones that bind to receptors on the surface of target cells and cannot pass through the phospholipid membrane.

Steroid hormones

Fat-soluble hormones made from cholesterol that can pass through cell membranes and affect gene expression.

Osteon

Grouping of concentric lamellae surrounding a central (Haversian) canal.

Canaliculi

Microscopic tunnels that allow communication between lacunae.

Octet Rule

Apart from hydrogen and helium, an atom’s valence shell is full when it contains 8 electrons.

Atom stability

Atoms are most stable when their valence shells are filled.

Period/Row relationship

An atom’s number of shells corresponds to its period (row) on the periodic table.

Group/Column relationship

Columns correspond to the number and configuration of an element’s valence electrons.

Order of elements

Elements are arranged by increasing atomic number; each element has one more proton than the element before it.

Longest long bone

Femur; contains the largest amount of yellow bone marrow.

Volkmann’s Canals

Channels through which blood vessels travel in bone.

Central (Haversian) canals

Passageways for nerves and blood vessels in bone.

Lacunae

Microscopic pockets between lamellae where bone cells reside.

Lamellae

Layers of bone tissue that make up an osteon.

2 most abundant molecules on Earth

Chitin and cellulose.

Fat molecule

1 glycerol + 3 fatty acids.

Noncovalent bonds

Hydrogen bonds and ionic bonds.

RNA molecules

Essential for converting information stored in DNA into proteins.

Distance formula

Distance = (speed of sound) × time.

Constant motion

Molecules above absolute zero are always moving (0 K = -273°C).

Ice vs water density

Ice is less dense than water, so it floats.

Mass Number

Mass Number = Protons + Neutrons

Atomic Number

Atomic Number = Protons

Neutrons

Neutrons = Mass Number − Atomic Number

Atomic Mass

Average mass of an element.

Fe

Iron.

Na

Sodium.

Dry ice

Example of sublimation (solid → gas).

Deposition

Gas → solid (example: ice crystals forming in clouds).

Triple Point

Temperature and pressure where solid, liquid, and gas coexist.

Critical Point

Temperature above which a substance coexists in both liquid and gas states.

Atlas (C1)

Allows head to nod 'yes.'

Axis (C2)

Allows head to shake 'no' due to the dens.

Prime mover

Contracting muscle.

Antagonist

Relaxing muscle.

Tendons

Attach muscle to bone.

Ligaments

Attach bone to bone.

Mineral resorption

Osteoclasts remove calcium from bone and release it into the bloodstream.

Mineralization

Osteoblasts deposit hydroxyapatite into bone matrix.

Hydrolysis

Water IN, breaks bonds apart.

Dehydration reaction (condensation)

Water OUT, forms bonds and builds larger molecules.

Peptide bond

Covalent bond linking amino acids.

Homeostasis

Maintenance of a constant internal environment through negative feedback mechanisms.

Renin

Produced by kidneys, regulates blood pressure.

Villi

Fingerlike projections in the small intestine that increase surface area & absorb nutrients.

Peyer’s Patches

Immune tissue in the ileum.

Endocrine glands

Ductless glands that release hormones into bloodstream. Slow onset, lasting effects. Examples include thyroid, pituitary, and adrenal glands that produce insulin and glucagon.

Exocrine glands

Glands that use ducts to secrete substances. Examples include sweat, salivary, and mammary glands which produce digestive enzymes.

Pancreas

An organ that functions as both an endocrine and exocrine gland.

Yellow bone marrow

Stores fat inside the medullary cavity of long bones.

Red bone marrow

Produces blood cells inside spongy bone.

Saltatory Conduction

A process in which a signal jumps from node to node in an axon.

Temporal Summation

A process where many signals arrive closely together and add up to trigger an action potential.

Vitamin D

A vitamin that helps absorb calcium and supports bone health; produced by UV light (sunlight).

Keratin

A protein found in hair, nails, and outer skin.

Osteon

The basic structural unit of compact bone.

Lamellae

Concentric rings that make up an osteon.

SI Units

The scientific measurement system.

Thermometer

Measures temperature in kelvin.

Balance

Measures mass in grams.

Ruler

Measures length in meters.

Beaker

Measures volume in liters/mL.

Pipette

Measures volume in liters/mL.

Empirical data

Data obtained through observation, measurement, or counting.

Carbohydrate

A type of macromolecule that includes sugars.

Monosaccharide

A single sugar unit.

Polysaccharide

Many sugar units bonded together.

Protein

A macromolecule made up of amino acids.

Lipids

Macromolecules that consist of fatty acids and glycerol.

Nucleic Acids

Macromolecules made of nucleotides, including DNA and RNA.

Ionic bond

A chemical bond formed by the transfer of electrons, resulting in attraction between oppositely charged ions, e.g., NaCl.

Polar covalent bond

A bond where electrons are shared unequally, resulting in partial charges.

Nonpolar covalent bond

A bond where electrons are shared equally, resulting in a balanced charge distribution.

Hydrogen bond

A weak attraction between molecules, such as between water molecules.

ISOTOPE

Atoms with the same number of protons but different numbers of neutrons.

Proton

A subatomic particle with a positive charge, located inside the nucleus.

Neutron

A subatomic particle with no charge, located inside the nucleus.

Electron

A subatomic particle with a negative charge, located outside the nucleus.

Physical Property

A characteristic that can be observed without changing the substance, such as mass, density, color, or melting point.

Chemical property

A characteristic that describes how a substance reacts, such as flammability, rusting, or reactivity.

Intensive Property

A property that does not depend on the amount of substance, e.g., density, color, boiling point.

Extensive Property

A property that does depend on the amount of substance, e.g., mass, volume, length.

Blood vessels

Structures that absorb the digested nutrients.

Smooth muscle

Muscle involved in moving material through the digestive system under parasympathetic nervous system control.

Saliva

A fluid that contains amylase, an enzyme that begins carbohydrate digestion in the mouth.