growth hormone (GH)

hormone produced in the anterior pituitary that stimulates growth in general. Also called somatotropin.

prolactin (PRL)

protein hormone produced in the anterior pituitary that stimulates milk production by the breasts.

oxytocin

hormone synthesized by the hypothalamus and secreted by the posterior pituitary that stimulates contraction of the uterus during childbirth and ejection of milk during nursing.

antidiuretic hormone (ADH)

hormone synthesized by the hypothalamus and secreted by the posterior pituitary that stimulates the kidneys to reabsorb more water, reducing urine volume

thyroid hormone (TH)

amine hormone that affects virtually every cell in the body and can increase basal metabolic rate and body heat production, regulate tissue growth and development, and maintain blood pressure. T3 and T4 compose it.

calcitonin

a polypeptide hormone released by parafollicular cells of the thyroid gland in response to rise of blood Ca2+ levels. It does not have a known physiological role.

parathyroid hormone (PTH)

a protein hormone that controls calcium balance in the blood by increasing Ca2+ levels by stimulating the skeleton, kidneys, and small intestine.

mineralcorticoids

steroid hormones secreted by the zona glomerulosa of the adrenal cortex that helps control the balance of minerals, especially K+ and Na+, and water in the blood.

aldosterone

the most potent mineralcorticoid secreted by the zona glomerulosa of the adrenal cortex that stimulates the kidney tubules to increase Na+ reabsorption and to secrete K+ for elimination.

glucocorticoids

adrenal corticosteroids secreted by the zona fasciculata of the adrenal cortex that influence the energy metabolism and help stress resistance by keeping blood glucose levels fairly constant and by maintaining blood pressure.

cortisol

the primary glucocorticoid secreted by the zona fasciculata of the adrenal cortex that provokes gluconeogenesis and enhances the vasoconstrictive effects of the sympathetic nervous system to maintain blood pressure.

gonadocorticoids

adrenal sex hormones secreted by the zona reticularis of the adrenal cortex.

androgens

male sex hormones that compose the majority of gonadocorticoids.

catecholamines

a group of chemically similar neurotransmitters that includes epinephrine, norepinephrine, and dopamine.

chromaffin cells

cells of the adrenal medulla innervated by sympathetic fibers that secrete epinephrine and norepinephrine.

insulin

hypoglycemic, amine hormone secreted by the pancreas that lowers blood glucose levels, promotes protein synthesis and fat storage, and participates in neuronal development. It triggers glycogen formation, oxidation of glucose for ATP, and the conversion of glucose to fat.

epinephrine

primary hormone secreted by the adrenal medulla that stimulates metabolic activities and bronchial dilation.

norepinephrine

secondary hormone secreted by the adrenal medulla that has a greater influence on peripheral vasoconstriction and blood pressure.

glucagon

hyperglycemic, amine hormone secreted by the pancreas that stimulates the liver to breakdown glycogen to glucose, synthesize glucose from noncarbohydrates, and release glucose into the bloodstream.

estrogen

female sex hormone secreted by the ovaries that initiates the maturation of the female reproductive organs and the appearance of secondary sex characteristics of females at puberty.

progesterone

female sex hormone secreted by the ovaries that works with estrogen to promote breast development and cyclic changes in the uterine mucosa.

testosterone

male sex hormone secreted by the testes that initiates the maturation of the male reproductive organs and the appearance of secondary sex characteristics and sex drive.

thymus

gland in the superior thorax that secretes thymulin, thymosins, and thymopoietins involved in the development of T lymphocytes.

adrenal medulla

a knot of sympathetic nervous tissue inside the adrenal glands that synthesizes epinephrine and norepinephrine.

hirsutism

abnormal hairiness caused by the hypersecretion of gonadocorticoids.

pancreas

mixed gland located posteriorly to the stomach with both exocrine and endocrine functions. Its primary endocrine function is regulation of blood glucose levels.

erythrocyte

an anucleate, organelle-less cell with a diameter of 7-8 um that transports respiratory gases with the protein, hemoglobin.

leukocyte

the only complete cell of the formed elements that defends the body.

neutrophil

the most common type of granulocyte or leukocyte with a multilobed nucleus, a diamter of 10-12 um, and pale (acidic) and blue (basic) granules that kill bacteria using respiratory bursts.

eosinophil

a type of granulocyte with a two-lobed nucleus, a diameter of 10-14 um, and red, acidic granules filled with digestive enzymes that leads the counterattack against parasitic worms and plays a complex role in other diseases like allergies and asthma.

basophil

the least common type of leukocytes or granulocytes with a u-shaped or s-shaped nucleus, a diameter of 10-14 um, and large, histamine-containing granules.

lymphocyte

agranulocyte and the second most numerous leukocyte with a diameter of 5-17 um and spherical nucleus that is closely associated with lymphoid tissues.

monocyte

the largest leukocyte or agranulocyte with a diameter of 14-24 um and u- or kidney-shaped nucleus that act as highly mobile macrophages in tissue.

platelet

a cytoplasmic fragment of a megakaryocyte with a diameter of 2-4 um that are essential for the clotting process that occurs in plasma when blood vessels are ruptured or damaged.

diapedesis

passage of leukocytes through intact vessel walls into tissue.

amoeboid motion

a crawling-like type of movement used by white blood cells to reach sites of inflammation or tissue destruction where the cell forms temporary cytoplasmic projections called psuedopodia.

granulocyte

a type of leukocyte with obvious membrane-bound cytoplasmic granules and lobed nuclei.

agranulocyte

a type of leukocyte with spherical or kidney-shaped nuclei that lacks visible cytoplasmic granules.

hematocrit

the percentage of total blood volume occupied by erythrocytes. 47.0+/-5 in males and 42.0+/-5 in females.

differential white blood cell count

a blood test that determines the relative proportions of individual leukocyte types.

agglutinogens

red blood cell antigens that determine blood type.

agglutinins

unique ABO antibodies that act against RBCs carrying ABO antigens that are not present on a person's own erythrocytes.

pulmonary circuit

system of blood vessels that serves gas exchange in the lungs and carries blood to and from the lungs.

systemic circuit

system of blood vessels that serves gas exchange in the body tissues and carries blood to and from the heart.

superior vena cava

the vein that returns blood from body regions superior to the diaphragm to the right atrium.

inferior vena cava

the vein that returns blood from body regions inferior to the diaphragm to the right atrium.

pulmonary trunk

the artery that routes the blood from the right ventricle of the heart to the lungs for gas exchange.

pulmonary arteries

subdivisions of the pulmonary trunk that takes deoxygenated blood to the lungs before subdividing.

pulmonary veins

the four veins exiting the lungs with oxygenated blood and emptying into the left atrium of the heart.

aorta

the largest artery in the body that routes the blood from the left ventricle of the heart to the body tissues.

tricuspid valve

the right atrioventricular valve that has three flexible cusps.

mitral valve

the left atrioventricular valve with two cusps.

pulmonary valve

the right semilunar valve that guards the base of the pulmonary trunk, preventing backflow into the right ventricle.

aortic valve

the left semilunar valve that guards the base of the aorta, preventing backflow into the left ventricle.

intercalated disc

a junction of cardiac muscle cells anchored by desmosomes and containing gap junctions, allowing the myocardium to contract as one unit.

functional syncytium

the myocardium behaving as a single coordinated unit.

intrinsic conducting system

noncontractile cardiac cells specialized to initiate and distribute impulses throughout the heart, so it depolarizes and contracts in an orderly, sequential manner.

cardiac pacemaker cell

a part of the intrinsic cardiac conduction system with the special ability to depolarize spontaneously.

sinoatrial node

specialized myocardial cells in the wall of the right atrium just inferior to the superior vena cava that sets the pace (called the pacemaker) for the heart as a whole due to its fast depolarization rate.

atrioventricular node

specialized myocardial cells in the inferior portion of the interatrial septum just superior to the tricuspid valve that briefly delays the impulse from the SA node.

atrioventricular bundle

a group of specialized fibers in the superior part of the interventricular septum that conducts impulses from the atrioventricular node to the left and right ventricles.

right bundle branch

a pathway of the atrioventricular bundle that courses along the right side of the interventricular septum to the heart apex.

left bundle branch

a pathway of the atrioventricular bundle that courses along the left side of the interventricular septum to the heart apex.

subendocardial conducting network

modified ventricular muscle fibers of the conduction system of the heart that depolarizes the contractile cells of both ventricles.

electrocardiogram (ECG)

a graphic record of the electrical changes occurring during the cardiac cycle.

segment

a region on an ECG between two waves.

interval

a region on an ECG that contains a segment and one or more waves.

fibrillation

a condition of rapid, uncoordinated heart contractions.

tachycardia

an abnormally fast heart rate, greater than 100 beats/minute.

bradycardia

an abnormally slow heart rate, less than 60 beats/minute.

P wave

the first wave of an ECG that represents the movement of the depolarization wave from the SA node through the atria.

P-R interval

the time from the beginning of atrial excitation to the beginning of ventricular excitation that also includes atrial depolarization.

QRS complex

the large, second wave of an ECG that represents ventricular depolarization and precedes ventricular contraction.

S-T segment

the section of an ECG that represents the time wen the entire ventricular myocardium is depolarized.

Q-T interval

the time from the beginning of ventricular depolarization through ventricular repolarization.

T wave

the small, third wave of an ECG that represents ventricular repolarization.

systole

the periods of contraction in the cardiac cycle.

diastole

the periods of relaxation in the cardiac cycle.

cardiac cycle

all the mechanical events associated with blood flow through the heart in one complete heartbeat.

quiescent period

the period of total heart relaxation of the cardiac cycle.

dicrotic notch

the result of a pressure fluctuation that occurs when the aortic valve snaps shut.

isovoluetric contraction phase

the time when the ventricles are completely closed chambers and the blood volume in the ventricles remains constant as the ventricles contract.

regurgitation

backflow of blood in the heart.

heart murmurs

abnormal heart sounds that indicate valvular problems where closure is followed by a swishing sound due to the backflow of blood.

sounds of Korotkoff

the sounds of blood spurting in the brachial artery that are used in determining blood pressure.

pulse pressure

the difference between systolic and diastolic blood pressures.

mean arterial pressure (MAP)

the pressure that propels the blood to the tissues. diastolic pressure + 1/3 pulse pressure.

larynx

tube connecting the laryngopharynx and the trachea with nine different cartilages that acts as an air passageway, prevents food from entering the lower respiratory tract, and produces voice.

thyroid cartilage

large hyaline cartilage with a large laryngeal prominence of the larynx that forms the framework of the larynx.

cricoid cartilage

single ring of hyaline cartilage located inferior to the thyroid cartilage and superior to the trachea.

laryngeal prominence

a large ridge on the anterior surface of the thyroid cartilage often referred to as the Adam's apple.

arytenoid cartilage

paired pyramid-shaped hyaline cartilages of the larynx that anchors the vocal folds.

corniculate cartilage

paired small horn-shaped cartilages located atop the arytenoid cartilages that form part of the posterior wall of the larynx.

cuneiform cartilage

paired wedge-shaped hyaline cartilages that form the lateral aspect of the laryngeal wall.

epiglottis

single flap of elastic cartilage anchored to the inner rim of the thyroid cartilage that forms a lid over the larynx when swallowing.

vocal folds

the true vocal cords (elastic fibers covered with mucous membrane attached to the arytenoid cartilage) that vibrate with exhaled air for sound production.

vestibular folds

the false vocal cords (elastic fibers covered with mucous membrane located superior to the vocal folds) that protect the vocal folds and help close the glottis when swallowing.

glottis

the vocal folds and the slitlike passageway between the vocal folds.

respiratory membrane

the blood air barrier formed by the alveolar and capillary walls where gas exchange occurs.

respiratory zone structures

the alveolar sacs, alveolar ducts, respiratory bronchioles collectively.

conducting zone structures

all respiratory passageways that serve as access or exit routes to the respiratory zone structures, such as the nasal cavity, trachea, bronchi, and terminal bronchioles.