Endocrine and Reproductive Human Anatomy and Physiology

Vocabulary flashcards covering human endocrine system, reproduction, embryonic development, fetal circulation, and birth concepts based directly on the lecture notes.

Endocrine gland

Ductless gland that secretes hormones directly into body fluids/blood.

Exocrine gland

Gland that secretes products through ducts or tubes.

Target cell

Cell containing the receptor required for a particular hormone.

Paracrine secretion

Chemical messenger that targets a nearby cell.

Autocrine secretion

Chemical messenger that targets the same cell that secreted it.

Steroid hormone

Cholesterol-derived lipid-soluble hormone that crosses the cell membrane and binds an intracellular receptor.

Nonsteroid hormone

Usually amino-acid-derived water-soluble hormone that binds a membrane receptor and uses a second messenger.

First messenger

Hormone that binds the membrane receptor in nonsteroid hormone signaling.

Second messenger

Intracellular chemical that relays a hormone signal; cAMP is a common example.

Upregulation

Increase in the number of receptors, often in response to decreased hormone levels.

Downregulation

Decrease in receptor number, often in response to increased hormone levels.

Negative feedback

Process where rising hormone level decreases further hormone secretion.

Anterior pituitary regulation

Hypothalamic releasing/inhibiting hormones travel through the hypophyseal portal system.

Posterior pituitary regulation

Neural regulation where action potentials from the hypothalamus cause hormone release.

Growth hormone (GH)

Anterior pituitary hormone that promotes tissue growth, protein synthesis, and fat use.

Prolactin

Anterior pituitary hormone that promotes milk production.

TSH

Anterior pituitary hormone that stimulates the thyroid to release T3 and T4.

ACTH

Anterior pituitary hormone that stimulates cortisol and other glucocorticoids from the adrenal cortex.

ADH

Hormone made in hypothalamus and released from posterior pituitary that conserves water, decreases urine, and can cause vasoconstriction.

Oxytocin

Hormone made in hypothalamus and released from posterior pituitary that causes uterine contractions and milk ejection.

T3

Thyroid hormone that increases metabolism and supports growth; approximately 5 times more potent than T4 in lecture.

T4

Thyroid hormone that increases metabolism and supports growth and nervous-system maturation.

Calcitonin

Thyroid C-cell hormone that decreases blood calcium.

PTH

Parathyroid hormone that increases blood calcium by stimulating bone breakdown, increasing renal calcium reabsorption, and indirectly increasing intestinal calcium absorption through vitamin D.

Hyperthyroidism

Condition with high T3/T4 causing fast metabolism, weight loss, restlessness/anxiety, rapid heart rate, and frequent bowel movements/diarrhea.

Graves' disease

Common cause of hyperthyroidism.

Hypothyroidism

Condition with low T3/T4 causing slow metabolism, weight gain, fatigue, slow heart rate, and constipation.

Hashimoto's disease

Common cause of hypothyroidism.

Adrenal medulla

Inner adrenal region that produces epinephrine and norepinephrine for rapid fight-or-flight.

Adrenal cortex

Outer adrenal region producing aldosterone, cortisol, and adrenal androgens.

Zona glomerulosa

Adrenal cortex layer that produces aldosterone.

Zona fasciculata

Adrenal cortex layer that produces cortisol.

Zona reticularis

Adrenal cortex layer that produces adrenal androgens.

Aldosterone

Mineralocorticoid that causes kidneys to retain sodium and water and excrete potassium, increasing blood volume/pressure.

Cortisol

Glucocorticoid involved in stress and glucose metabolism that decreases protein synthesis, increases fatty-acid release, and increases glucose formation.

Alpha pancreatic cells

Cells in the pancreas that produce glucagon.

Beta pancreatic cells

Cells in the pancreas that produce insulin.

Delta pancreatic cells

Cells in the pancreas that produce somatostatin.

Insulin

Pancreatic hormone that lowers blood glucose and facilitates glucose use/entry by cells.

Glucagon

Pancreatic hormone that raises blood glucose.

Somatostatin

Pancreatic hormone that inhibits secretion of insulin and glucagon.

Melatonin

Pineal hormone regulating circadian rhythms.

Thymosins

Thymus hormones that promote T-lymphocyte development.

Erythropoietin

Kidney hormone that stimulates red blood cell formation.

General adaptation syndrome

Three-stage response to prolonged stress: alarm, resistance, exhaustion. GAS stage order - Alarm → Resistance → Exhaustion.

Meiosis I

Division in which homologous chromosomes separate.

Meiosis II

Division in which sister chromatids separate.

Seminiferous tubules

Tubules within testes where sperm production occurs.

Interstitial/Leydig cells

Testicular cells that produce testosterone in response to LH.

Sertoli/sustentacular cells

Cells that support and nourish developing sperm and produce inhibin.

Epididymis

Coiled tube where sperm mature and are stored.

Vas deferens

Muscular tube that stores/transports sperm.

Seminal vesicles

Glands that produce alkaline, fructose-containing fluid that nourishes and supports sperm.

Prostate

Gland that adds thin/milky slightly alkaline fluid and enzymes to semen.

Bulbourethral glands

Glands that produce alkaline mucus/pre-ejaculate that lubricates and helps neutralize the urethra.

Acrosome

Part of the sperm head containing enzymes used to penetrate structures surrounding the oocyte.

Endometrium

Inner uterine lining that changes during the menstrual cycle and receives implantation.

Myometrium

Smooth-muscle layer of uterus.

Perimetrium

Outer uterine covering.

Secondary oocyte

Cell produced after primary oocyte completes meiosis I; begins meiosis II but stops at metaphase II until fertilization.

Corpus luteum

Structure formed from ruptured follicle that secretes progesterone.

Corpus albicans

Degenerated corpus luteum when pregnancy does not occur.

LH surge

Hormonal event that triggers ovulation.

Estrogen

Hormone that promotes female secondary sex characteristics and endometrial growth.

Progesterone

Hormone that prepares and maintains the endometrium for possible pregnancy.

Corona radiata

Cell layer surrounding secondary oocyte that sperm must penetrate.

Zona pellucida

Protective layer around oocyte; sperm binds it and it later hardens to help prevent additional sperm entry.

Pronuclei

Male and female nuclei before they unite during fertilization.

Zygote

Cell produced by fertilization containing 46 chromosomes.

Cleavage

Rapid mitotic divisions that increase cell number without increasing overall embryo size. Cleavage sequence - 2-cell → 4-cell → 8-cell → morula → blastocyst.

Blastomeres

Smaller cells produced during cleavage.

Morula

Solid ball of approximately 16–32 cells.

Blastocyst

Hollow ball of cells that attaches to the endometrium.

Inner cell mass

Part of blastocyst that becomes embryo proper.

Trophoblast

Outer blastocyst cells that contribute to supporting/placental structures.

Implantation

Blastocyst attachment and embedding in the endometrium.

hCG

Hormone produced by trophoblast cells during implantation.

Chorion

Outermost extraembryonic membrane; chorionic villi contribute fetal portion of placenta.

Amnion

Innermost membrane that forms the amniotic sac.

Yolk sac

Structure for early nutrient transfer, first site of hematopoiesis, and source of germ-cell precursors according to lecture.

Allantois

Structure that contributes to umbilical blood vessels and early waste/fluid functions.

Gastrulation

Developmental process beginning around week 3 that forms the three primary germ layers.

Organogenesis

Formation of organs from the primary germ layers.

Teratogen

Agent/factor capable of causing abnormal development.

Ductus venosus

Shunts oxygenated blood from umbilical vein to inferior vena cava, bypassing most of liver; becomes ligamentum venosum after birth.

Foramen ovale

Opening between right and left atria allowing right atrium to left atrium blood flow to bypass lungs; becomes fossa ovalis after birth.

Ductus arteriosus

Connects pulmonary trunk/artery to aorta and bypasses lungs; becomes ligamentum arteriosum after birth.

Relaxin

Hormone from corpus luteum and placenta that inhibits uterine contractions and relaxes pelvic ligaments.

Parturition

Birth process at the end of pregnancy.

Colostrum

First thin/watery milk; rich in proteins and antibodies and lower in carbohydrates/fats than mature milk.

Neonatal period

Time frame from birth through the end of the fourth week.

Anterior pituitary hormones

GH, prolactin, TSH, ACTH, FSH, and LH.

Posterior pituitary hormones

ADH and oxytocin.

FSH in females

Promotes ovarian follicle development and estrogen production.

FSH in males

Supports sperm production.

LH in females

Triggers ovulation and corpus luteum formation and promotes sex-hormone production.

LH in males

Stimulates Leydig/interstitial cells to produce testosterone.

Epinephrine and norepinephrine

Adrenal medulla hormones involved in immediate fight-or-flight.

Purpose of meiosis

Produces haploid gametes containing 23 chromosomes.

Prophase I

Homologous chromosomes pair and crossing over may occur.