Biology Flashcards
Synonymous with antibody; produced in response to a specific foreign substance that recognizes and binds to that antigen and triggers an immune response.
Immunoglobulin
Vessels that carry blood toward the heart. These vessels are thin-walled and have valves to prevent backflow.
Veins
Synthesized and released by the thyroid gland, thyroid hormones triiodothyronine (T3) and thyroxine (T4) stimulate cellular respiration as well as protein and fatty acid synthesis and degradation.
Thyroid Hormones
A hormone that is secreted by the duodenum in response to the presence of chyme. CCK stimulates the release of bile and pancreatic enzymes into the small intestine, and promotes satiety.
Cholecystokinin (CCK)
The portion of the cell containing the centrioles.
Centrosome
Describes a situation in which an organism heterozygous for a trait will have a phenotype that expresses both alleles in full. Both alleles, therefore, are dominant.
Codominance
Insulating structure that surrounds axons. Action potentials cannot take place in areas of the axon that are myelinated.
Myelin Sheath
Type of muscle found within the heart; may contain one or two nuclei. Involuntary, like smooth muscle, but appears striated, like skeletal muscle. Able to depolarize independent of the nervous system.
Cardiac Muscle
Hormones that are synthesized by modifying amino acids. Most amino acid-derivative hormones act via secondary messengers, while some act in a fashion similar to steroid hormones.
Amino Acid-Derivative Hormones
Genes coding for alternative forms of a given trait.
Alleles
A surface protein expressed on red blood cells that can induce an immune response. Introduction of Rh factor into the blood of a person who is Rh- may result in a fatal hemolysis reaction.
Rh Factor
Synthesizes and releases many vital hormones, including follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, prolactin, endorphins, and growth hormone (“FLAT PEG”). The anterior pituitary is under the hormonal control of the hypothalamus.
Anterior Pituitary
An alkaline fluid synthesized in the liver, stored in the gall bladder, and released into the duodenum. Bile aids in the emulsification, digestion, and absorption of fats.
Bile
The central nervous system consists of the brain and the spinal cord.
Central Nervous System
An organism that makes ATP by aerobic respiration if oxygen is present, but that can switch to fermentation for sufficient ATP when oxygen is not available.
Facultative Anaerobe
The simplest division of a set of values; the middle value that divides the values into the upper half and lower half.
Median
The two thin-walled upper chambers of the heart. The right atrium receives deoxygenated blood from the venae cavae, while the left atrium receives oxygenated blood from the pulmonary veins.
Atria
Much more dense than spongy bone, compact bone consists of Haversian systems (osteons).
Compact Bone
Method of asexual reproduction by which prokaryotes divide. The circular DNA molecule replicates and then moves to the edge of the cell. The cell then divides into two daughter cells of equal size.
Binary Fission
Mutation in which a number of nucleotides (except multiples of three) are either deleted or inserted. Such mutations lead to a shift in the DNA reading frame and often result in the translation of nonfunctional proteins.
Frameshift Mutation
The likelihood of two genes on the same chromosome being separated during crossing over onto two different chromosomes; equal to the proportion of gametes that receive these recombinant chromosomes. If the recombination frequency of two particular traits is high, it can be inferred that they lie far apart from each other.
Recombination Frequency
The stage of the cardiac cycle in which the heart muscle relaxes and collects blood into its chambers.
Diastole
The layer of skin beneath the epidermis that is subdivided into the papillary layer and the reticular layer. It contains the sweat glands, sense organs, blood vessels, and the bulbs of hair follicles; it is derived from the mesoderm.
Dermis
A substance that is bound by an antibody, causing an immune reaction.
Antigen
Stem cells that can differentiate into multiple cell types within a particular group. For example, hematopoietic stem cells are able to differentiate into many different types of blood cells, but not into any other cell type.
Multipotent
Describes an allele that requires two copies to be expressed.
Recessive
Type of natural selection where the average phenotype is favored while those outside the norm are eliminated.
Stabilizing Selection
The fluid discharged during ejaculation. Semen consists of sperm cells and seminal fluid (fluid from the prostate and bulbourethral glands).
Semen
Lighter and less dense than compact bone, it consists of an interconnecting lattice of bony spicules (trabeculae). The cavities between the spicules contain bone marrow.
Spongy Bone
Slow-twitch muscle fibers. They are primarily aerobic and contain many mitochondria and high levels of myoglobin.
Red Fibers
Section of the digestive tract that can be subdivided into three sections: duodenum, jejunum, and ileum. Most digestion takes place in the duodenum and most absorption takes place in the jejunum and the ileum.
Small Intestine
Maintenance of a constant internal body temperature.
Thermoregulation
The separation of homologous chromosomes during anaphase I of meiosis.
Disjunction
Expressed as breaths per minute. Raising the respiratory rate can decrease the amount of carbon dioxide in the blood, thus increasing the pH. Likewise, decreasing the respiratory rate increases the concentration of carbon dioxide in the blood, resulting in a lower pH.
Respiratory Rate
Circulatory routes in which blood travels through two capillary beds before returning to the heart. Some examples include the hypophyseal portal system, the hepatic portal system, and the renal portal system.
Portal Systems
A solid ball of cells that develops from the zygote through cleavage. When the interior of the morula becomes hollow, it becomes known as a blastula.
Morula
The organ formed by the uterus and the extraembryonic membranes of the fetus. The placenta contains a network of capillaries through which exchange between the fetal circulation and the maternal circulation takes place.
Placenta
A fertilized egg. Develops into a morula after a number of rounds of cleavage.
Zygote
Fast-twitch muscle fibers. They are primarily anaerobic and fatigue more easily than red fibers.
White Fibers
Fingerlike projections that extend out of the small intestine in order to increase surface area for maximal absorption.
Villi
The muscular lower chambers of the heart. The right ventricle pumps deoxygenated blood to the lungs through the pulmonary arteries, while the left ventricle pumps oxygenated blood throughout the body through the aorta.
Ventricles
Synthesized and released by the anterior pituitary, TSH stimulates the thyroid gland to absorb iodine and to synthesize and secrete thyroid hormones. TSH is regulated by thyroid releasing hormone (TRH), which is released by the hypothalamus.
Thyroid-Stimulating Hormone (TSH)
Synthesized and released by the parathyroid gland, PTH increases blood Ca^2+ concentration by increasing Ca2+ reabsorption in the kidneys and by stimulating calcium release from bone.
Parathyroid Hormone (PTH)
The material that passes from the blood vessels into Bowman’s space.
Filtrate
Plasmids that have the ability to integrate into the host genome.
Episomes
Carries nutrients (monosaccharides, amino acids, and small fatty acids) absorbed in the small intestine to the liver, where they are modified to enter circulation.
Hepatic Portal Vein
The group of cells in a blastocyst (mammalian blastula) that develop into the embryo.
Inner Cell Mass
Network of capillaries within Bowman’s capsule that serves as the site of filtration. Blood cells and proteins are too large to be filtered, but ions, glucose, and amino acids readily pass into the filtrate.
Glomerulus
A protein secreted by parietal cells of the stomach that is necessary for vitamin B12 absorption.
Intrinsic Factor
Stores and releases hormones (oxytocin and ADH) synthesized by the hypothalamus. The release of these hormones is triggered by an action potential that originates in the hypothalamus.
Posterior Pituitary
A steroid hormone produced in the adrenal cortex that is responsible for reabsorption of sodium and water and excretion of potassium and hydrogen ions.
Aldosterone
A shunt that connects the right atrium to the left atrium in order to bypass the fetal lung.
Foramen Ovale
Produced and secreted by the δ-cells of the pancreas, somatostatin inhibits the release of glucagon and insulin.
Somatostatin
One of the twelve cranial nerves that provides parasympathetic signaling to the thoracic and abdominal cavities.
Vagus Nerve
Enzyme that catalyzes the conversion of carbonic acid to carbon dioxide and water as well as the formation of carbonic acid from carbon dioxide and water. Important in the bicarbonate buffer system.
Carbonic Anhydrase
A system of tubules that provides channels for ion flow throughout skeletal and cardiac muscle fibers to facilitate the propagation of an action potential.
Transverse Tubules (T-Tubules)
Secreted as pepsinogen by the chief cells of the stomach, this enzyme cleaves peptide bonds, starting the digestion of proteins into individual amino acids.
Pepsin
Glands that synthesize and secrete hormones into the circulatory system. Examples include the hypothalamus, pituitary gland, pineal gland, pancreas, testes, ovaries, adrenal glands, thyroid gland, and parathyroid glands.
Endocrine Glands
A multilayered sac of cells that protects and nourishes the developing ovum.
Follicle
The outermost of the three primary germ layers; gives rise to the skin, nervous system, lens of the eye, and inner ear.
Ectoderm
Created by analyzing recombination frequencies of linked genes; a schematic that shows the distance between two genes or the order of several genes on a chromosome.
Genetic Map
A shunt that connects the pulmonary artery to the aorta in order to bypass the fetal lung.
Ductus Arteriosus
Cells that produce myelin in the peripheral nervous system.
Schwann Cells
The innermost of the three primary germ layers; gives rise to the linings of the digestive and respiratory tracts and to parts of the liver, pancreas, thyroid, and bladder.
Endoderm
Organisms that require a host cell to express their genes and reproduce.
Obligate Intracellular Organisms
A collection of millions of neurons within the gastrointestinal system that governs the function of the GI tract. This system is able to function independently of the brain and spinal cord.
Enteric Nervous System
Hormone synthesized and released by the thyroid gland that decreases plasma Ca^2+ concentration.
Calcitonin
A balance between hydrostatic and oncotic pressure on both sides of a membrane, essential for maintaining proper fluid volumes and solute concentrations inside and outside the vasculature.
Starling Forces
Cells in the bone matrix that are involved in bone degradation.
Osteoclasts
Mutation in which one nucleotide base is substituted by another. The protein products may or may not be functional.
Point Mutation
Synthesizes and releases corticosteroids. Glucocorticoids are stimulated by adrenocorticotropic hormone (ACTH), whereas mineralocorticoids are stimulated by angiotensin II. Cortical sex hormones include androgens like testosterone.
Adrenal Cortex
Valves (the aortic valve and the pulmonic valve) that prevent backflow of blood from the arteries into the ventricles.
Semilunar Valves
Synthesizes and releases epinephrine and norepinephrine, which stimulate an increase in the metabolic rate and blood glucose levels.
Adrenal Medulla
The central cavity in the gastrula stage of embryological development; it is lined by endoderm and ultimately gives rise to the adult digestive tract.
Archenteron
Neurons that carry information to the central nervous system from the periphery. Also called sensory neurons.
Afferent Neurons
A unit of DNA that encodes a specific protein or RNA molecule.
Gene
A small, short-lived haploid cell created during oogenesis that receives very little cytoplasm, organelles, or nutrients.
Polar Body
Hormone synthesized and released by the ovaries, corpus luteum, and placenta. During the luteal stage of the menstrual cycle, the corpus luteum secretes progesterone, which, along with estrogen, stimulates the development and maintenance of the endometrial walls for implantation of the embryo.
Progesterone
A large vein that returns deoxygenated blood from the head and neck regions, as well as the upper extremities, to the right atrium of the heart.
Superior Vena Cava
Digestive enzyme secreted by cells in the duodenum. This enzyme converts trypsinogen to trypsin. Trypsin is then able to activate other pancreatic enzymes to allow digestion to continue within the duodenum.
Enteropeptidase
The most frequently occurring value in a set of observations.
Mode
The space between the axon terminal of one neuron and the dendrite of another neuron (or membrane of an effector organ) where neurotransmitters are released.
Synapse
Polar hormones incapable of permeating the cell membrane that bind to surface receptors and act through secondary messengers.
Peptide Hormones
A small molecule that transduces a hormonal signal from the exterior of the cell to the interior. Usually released when a peptide hormone binds to its receptor; cAMP is a common example.
Second Messenger
The stage of the cardiac cycle in which the heart muscle contracts and pumps blood.
Systole
The electrical impulse originates in the sinoatrial (SA) node, located in the right atrium. And then travels through the atrioventricular (AV) node, then through the bundle of His, and finally through the Purkinje fibers.
Pathway of the Electrical Impulse in the Heart
Essential organ of the human body responsible for the production of bile, detoxification of ingested substances, production of urea, and the processing and modification of nutrients for storage. The liver also produces albumin (a protein that maintains blood oncotic pressure) and clotting factors.
Liver
A short period of time immediately following an action potential in which neurons or muscle cells are unresponsive to a stimulus (absolute refractory period). In some cases, a stimulus that is much larger than usual causes an action potential in a cell in a refractory period (relative refractory period).
Refractory Period
All cells excluding the germ (reproductive) cells.
Somatic Cells
A highly specific form of immunity that develops in response to exposure to pathogens; consists of both humoral immunity and cytotoxic immunity.
Adaptive Immunity
Hormone secreted by the interstitial cells of the testes. Testosterone is responsible for embryonic sexual differentiation, male sexual development, and the maintenance of masculine secondary sexual characteristics.
Testosterone
A valve located between the right atria and the right ventricle. The valve consists of three cusps and prevents backflow of blood from the right ventricle to the right atrium.
Tricuspid Valve
Located in the testes, the seminiferous tubules are the site of sperm production.
Seminiferous Tubules
Ends of axons that form one side of the synaptic cleft; the location where vesicles of neurotransmitters are stored.
Synaptic Terminals
Subsequent infections by pathogens that trigger a more immediate response from the memory cells produced during the primary immune response.
Secondary Response
Stem cells that have the ability to become any cell within any system of the body. Embryonic stem cells are totipotent.
Totipotent
Portion of the nephron permeable only to water. The filtrate becomes more concentrated (loses water) as it travels through the descending limb due to the increasing concentration of the interstitium.
Descending Limb of the Loop of Henle
Portion of the nephron permeable to water and ions. As the filtrate flows down the collecting duct through the increasing concentration of the interstitium, the filtrate is concentrated. The degree of water reabsorption in the collecting duct is controlled by the action of the hormone ADH.
Collecting Duct
