final exam for summer session

Gonads

Primary sex organs (testes and ovaries) that secrete hormones and produce gametes

Dartos muscle

Muscle that wrinkles scrotal skin, moving testes closer to the body for warmth

Cremaster muscle

Muscle that elevates the testes closer to the body

Tunica albuginea

Fibrous capsule of the testis containing lymphatic vessels, nerves, and blood vessels

Seminiferous tubules

Site of sperm production within the testes

Myoid cells

Cells that contract to push sperm and testicular fluid through the tubules and out of the testes

Interstitial (Leydig) cells

Cells that surround seminiferous tubules and produce androgens/testosterone

Sustentacular (Sertoli) cells

Cells on the basement membrane of seminiferous tubules that support developing sperm, form the blood-testis barrier, and secrete testicular fluid, ABP, and inhibin

Blood-testis barrier

Barrier formed by tight junctions of sustentacular cells that separates developing sperm from the immune system

Spermatogenesis

Production of sperm cells

Spermiogenesis

Maturation of spermatids into mature sperm

Spermatogonia

Undifferentiated, diploid (2n) germ cells that divide by mitosis and can become primary spermatocytes

Primary spermatocyte

Cell that undergoes meiosis I to form secondary spermatocytes

Spermatid

Haploid (n) cell produced at the end of meiosis; 4 form from each primary spermatocyte

Acrosome

Structure covering the sperm head containing enzymes that aid fertilization

Flagellum (sperm)

Tail structure that provides sperm mobility

Epididymis

Site of sperm maturation and storage; absorbs excess testicular fluid and provides nutrients

Ductus (vas) deferens

Tube that carries sperm and testicular fluid from the epididymis to the ejaculatory duct

Ejaculatory duct

Junction of the seminal vesicle duct and ductus deferens; passes through the prostate

Urethra (male)

Tube connecting the ejaculatory duct/bladder to the outside; transports semen and urine; has prostatic, membranous, and spongy regions

Seminal vesicles

Glands that secrete seminal fluid (60-70% of semen volume) containing fructose, prostaglandins, and coagulating proteins

Fructose (seminal fluid)

Sugar in seminal fluid used as an energy source for sperm

Prostaglandins (seminal fluid)

Stimulate smooth muscle contractions and promote sperm viability/survival

Coagulating proteins

Form a temporary clot in the female reproductive tract after ejaculation

Prostate gland

Gland that secretes prostatic fluid (20-30% of semen volume) containing citric acid, PSA, and antimicrobial chemicals

Citric acid (prostatic secretion)

Energy source in prostatic fluid that supports capacitation

Prostate-specific antigen (PSA)

Enzyme that dissolves the semen clot formed by coagulating proteins

Bulbourethral (Cowper's) glands

Glands that secrete thick alkaline mucus prior to ejaculation to neutralize urine and lubricate the urethra

Erectile bodies

Corpus cavernosa and corpus spongiosum; fill with blood during arousal

Glans

Enlarged tip of the penis containing the external urethral orifice

Gonadotropin-releasing hormone (GnRH)

Hormone secreted by the hypothalamus that stimulates the anterior pituitary to release FSH and LH

Follicle-stimulating hormone (FSH, male)

Stimulates sustentacular cells to produce androgen-binding protein

Luteinizing hormone (LH, male)

Stimulates interstitial cells to produce testosterone

Androgen-binding protein (ABP)

Binds and concentrates testosterone within the seminiferous tubules

Testosterone

Androgen that stimulates spermatogenesis and development of male secondary sex characteristics

Inhibin (male)

Hormone that decreases FSH secretion when sperm production is elevated

Erection

Enlargement/stiffening of the penis due to increased blood flow to erectile tissue

Emission

Movement of sperm and glandular secretions into the urethra during ejaculation

Expulsion

Contraction of muscles at the base of the penis to expel semen

Capacitation

Functional changes sperm undergo in the female reproductive tract enabling fertilization

Mons pubis

Fatty area over the front of the pelvis

Labia majora

Larger, elongated, fatty skin folds that enclose and protect external genitalia

Labia minora

Smaller, thin skin folds that protect the clitoris, vaginal, and urethral openings

Vagina

Thick-walled, elastic, muscular canal that receives the penis, serves as the birth canal, and is a passageway for menstrual fluid

Cervix

Narrow neck of the uterus extending into the vagina; contains pressure/stretch receptors

Perimetrium

Outer serous layer of the uterus

Myometrium

Thick, smooth-muscle middle layer of the uterus

Endometrium

Inner lining of the uterus; made of stratum functionalis and stratum basalis

Stratum functionalis

Layer of endometrium that cyclically thickens and sheds

Stratum basalis

Layer of endometrium that regenerates the stratum functionalis after shedding

Uterine (fallopian) tubes

Structures that transport ova to the uterus; site of fertilization (ampulla)

Fimbriae

Finger-like projections that sweep the ovulated oocyte into the uterine tube

Ovaries

Gonads that secrete estrogen and progesterone and house oocytes

Ovarian cortex

Outer region of the ovary where oogenesis and follicle development occur

Ovarian medulla

Inner region of the ovary containing blood vessels, lymphatics, and nerves

Oogenesis

Process of egg (ovum) development

Oogonia

Diploid germ cells in the fetal ovary that undergo mitosis

Primary oocyte

Oocyte formed when oogonia begin meiosis I during fetal development

Secondary oocyte

Cell formed when a primary oocyte completes meiosis I; ovulated but paused in meiosis II

Menopause

Occurs when the supply of primary oocytes runs out

Primordial follicle

Earliest follicle stage with a single layer of follicle cells

Primary follicle

Follicle stage where granulosa and thecal cells develop

Secondary follicle

Follicle stage where follicle cells expand and granulosa cells secrete follicular fluid

Vesicular (Graafian) follicle

Mature follicle with a fluid-filled antrum

Corona radiata

Layer of granulosa cells surrounding the ovulated oocyte

Corpus luteum

Structure formed from remaining granulosa/thecal cells after ovulation; produces progesterone

Corpus albicans

Degenerated corpus luteum formed when implantation does not occur

Menstrual phase

Days 1-5 of the uterine cycle; stratum functionalis sheds

Proliferative phase

Days 6-14 of the uterine cycle; new stratum functionalis develops

Secretory phase

Days 15-28 of the uterine cycle; endometrial glands secrete uterine milk

Granulosa cells

Ovarian cells stimulated by FSH to convert androgens to estrogen and produce inhibin

Thecal cells

Ovarian cells stimulated by LH to produce androgens

Estrogen

Hormone that drives oogenesis/ovulation, thickens endometrium, and thins cervical mucus

Progesterone

Hormone that sustains pregnancy, prevents uterine contractions, and thickens cervical mucus

Pre-embryonic period

Stage of development from fertilization to week 2

Embryonic period

Stage of development from week 2 to week 8

Fetal period

Stage of development from week 9 to birth

Zona pellucida

Glycoprotein-rich layer surrounding the oocyte that develops during the primary follicle stage

Perivitelline space

Fluid-filled space between the zona pellucida and the oocyte's plasma membrane

Capacitation (fertilization step 1)

First step of fertilization where sperm becomes fully motile and surface receptors are exposed

Acrosomal reaction

Step where sperm travels through the corona radiata, binds zona pellucida receptors, and releases enzymes to break down the zona pellucida

Cortical granules

Released when sperm enters the oocyte; enzymes destroy sperm-binding receptors to block polyspermy

Pronucleus

Genetic material of the sperm or oocyte before they combine during fertilization

Cleavage

Rapid mitotic divisions beginning ~30 hrs after fertilization; cell number increases, cell size decreases

Morula

16-cell stage of the developing embryo, still within the zona pellucida

Blastocyst

Stage after the embryo leaves the zona pellucida; has an inner cell mass and trophoblast

Inner cell mass

Pluripotent stem cells within the blastocyst that develop into the embryo

Trophoblast cells

Outer cell ring of the blastocyst that helps form the placenta and suppresses the maternal immune system

Human chorionic gonadotropin (hCG)

Hormone that maintains the corpus luteum; detected by pregnancy tests

Syncytiotrophoblast

Trophoblast layer that merges together, digests uterine lining, and produces hCG

Cytotrophoblast

Trophoblast layer that facilitates formation of chorionic villi

Epiblast

Layer of the inner cell mass that becomes the embryonic disc

Lacunae

Spaces formed when syncytiotrophoblast breaks down uterine blood vessels, pooling maternal blood

Yolk sac

First extraembryonic membrane to develop; forms part of digestive system, blood cells/vessels, and first germ cells

Amnion

Membrane enclosing the embryo/fetus in amniotic fluid

Amniotic fluid

Fluid that maintains temperature/pressure, allows movement, and comes from filtered maternal blood and fetal urine

Allantois

Membrane forming the base of the umbilical cord; develops into part of the urinary bladder

Chorion

Outermost membrane forming the embryonic part of the placenta and producing hCG

Gastrulation

Process establishing body axes and forming the three germ layers

Germ layers

Endoderm, mesoderm, and ectoderm; the three layers formed during gastrulation