MEIOSIS

General terms

1. Diploid – 2n; cells which have the full number of chromosomes; 46

2. Haploid – n; gametes have only half the normal amount; 23

3. Homologous pairs – 1 from each parent; 23 pairs; different forms of same trait

4. Mitosis – 2 cells with diploid number; same number as mother cell

5. Meiosis – 4 cells with haploid number; half the mother cells; 2 cell divisions

Mitosis

1. Purpose – carried on through out body

2. Sister chromatid – each contain identical genetic information; centromere

3. Interphase – replication of genetic material

4. Prophase – chromatin condenses to become chromosomes

-a. Chromatid – each chromosome consist of two sister chromatid

5. Metaphase – chromosomes line up middle of cell

6. Anaphase – sister chromatid pulled to different poles

7. Telophase – new cells form; start with 2n, wind up with 2n

Meiosis I

1. Prophase I – chromosomes form; each with 2 sister chromatids

-a. Synapsis – homologous chromosomes align

-b. Tetrads (bivalents) – 4 sister chromatids; 2 from each homologous pair

-c. Crossing over – homologous chromosomes exchange bits

2. Metaphase I – tetrads line up along the equator

3. Anaphse I – 1 member of each homologous pair pulled to opposite poles

-a. Independent assortment – 2^x , x = number of homologous pairs; >8 million

4. Telophase 1 – nuclear envelope; cytokenesis (not completely in sperm)

5. Interkinesis – like interphase; nuclear material not reproduced

Meiosis II

1. Prophase II – envelope disappears; chromatin condense

2. Metaphase II – chromosomes line up along equator

3. Anaphase II – sister chromatids pulled to opposite ends

4. Telophase II – envelope; nucleolus; cytokinesis (not complete in sperm)

MALE REPRODUCTIVE SYSTEM: ANATOMY

Scrotum

1. Scrotum - bag of skin, fascia hanging outside abdominopelvic cavity

2. Testes - are suspended in the scrotum

3. Midline septum - separates the scrotum into right and left halves

4. Adaptation - viable sperm not produced body temp.; 3 degrees cooler

5. Temperature regulation – cold, closer wrinkles; warm hangs lose

6. Dartos muscle - smooth muscle layer; wrinkle the skin when cold

7. Cremaster muscle - bands muscle from internal oblique elevate testes

Testes

1. Tunics – has two coverings

-a. Tunica vaginalis – outer, two layered; from peritoneum

-b. Tunica albuginea – fibrous capsule; covers testes; lobules from septa

-c. Lobules – about 300 wedge shaped compartments

2. Seminiferous tubules – 1 – 4 each wedge; tightly coiled sperm factory

3. Tubulus rectus – straight tube; all seminiferous tubules of a lobule; to

4. Rete testis – tubular network; from here epididymis

5. Interstitial cells (Leydig cells) – between tubules; make testosterone

6. Spermatic cord – connective tissue sheath; encloses all; vas deferens

The male duct system

1. Epididymis – comma; head caps penis

-a. Efferent ductules – collect sperm from rete testis

-b. Location – posteriorlateral aspect of the testes

-c. Size – uncoiled length of about six meters

-d. Sperm maturation – 20 days in epididymis; feed; begin to swim

-e. Ejaculation – smooth muscles in walls of epididymis; eject

2. Ductus deferens – 45 cm long; spermatic cord; inguinal canal

-a. Ampulla – ductus deferens expands before entering ejaculatory duct

-b. Ejaculation – smooth muscles in ductus deferens; peristalsis

3. Ejaculatory duct – from seminal v. and d. def.; in prostate; to urethra

4. Urethra – three named parts

-a. Prostatic urethra – from bladder; surrounded by prostate

-b. Membranous urethra – urogenital diaphragm

-c. Penile (spongy) urethra – through penis

Accessory glands

1. Seminal vesicles – size of little finger; posterior bladder; paired

-a. Secretions – 60% of ejaculate; yellow viscous; fructose; alkaline

2. Prostate gland – single donut shaped gland

-a. Secretions – about 1/3^rd ; citrate nutrient; enzymes; PSA; activation

3. Bulbourethral gland – double; pea shaped; inferior to prostate

-a. Secretions – prior to ejaculation; thick mucus; neutralize acid urine

-b. Cowper’s gland – alternative name

Penis

1. Root – attached base of the penis

2. Shaft – hangs loose

3. Glans penis – enlarged (corpus spongiosum) tip

4. Bulb – enlarged (corpus spongiosum) proximal; muscle attaches

5. Prepuce (foreskin) – cuff of loose skin around the glans

6. Erectile tissue – spongy network of connective and s. muscle; engorge

-a. Corpus spongiosum – midventral; surrounds urethra

-b. Corpora cavernosa – paired; dorsal; most of penis

-c. Tunica albuginea – fibrous connective tissue sheath; binds all three

Semen

1. Characteristics – milky white, sticky, mixture of sperm and excretions

2. Purpose – transport, nutrient source, activate, protect sperm

3. Fructose – from seminal vesicles; nutrient source

4. Sperm mobility – increased by relaxin and enzymes

5. Alkaline – neutralize vaginal acidity

6. Sperm – in 2 t0 5 ml of semen; 50 to 130 million sperm per ml

MALE REPRODUCTIVE SYSTEM: PHYSIOLOGY

Male sexual response

1. Erection – enlargement and stiffening of the penis

-a. Parasympathetic reflex – stimuli results in opening of arterioles

-b. Vascular spaces – in the erectile tissue fill

-c. Venous outflow – impeded by compression of drainage veins

-d. Bulbourethral gland – also parasympathetic; lubricate glans

-e. Impotence – emotional, vascular, or nervous system

2. Ejaculation – propulsion of sperm from the duct system

-a. Sympathetic– stimuli ; spinal reflex; penile sympathetic nerves

-b. Contraction – of smooth muscle in ducts and glands

-c. Bladder sphincter muscle – constricts; no urine or semen backflow

-d. Bulbospongiosus muscle – rapid series of contraction; 200”/s

-e. Climax (orgasm) – accompanies; pleasure;↑HR, BP, muscles contract

-f. Latent period – minutes to hours; longer as one ages

Spermatogenesis

1. Seminiferous tubules – cells in the wall at different stages of meiosis

2. Spermatagonia mitosis – forms two types of cells (after puberty)

-a. Spermatagonia – stem cell; in contact of basal lamina of epithelium

-b. Type A daughter cell – becomes a spermatagonium; basal lamina

-c. Type B daughter cell – toward lumen; become primary spermatocyte

3. Primary spermatocyte meiosis – forms four haploid cells

-a. Secondary spermatocytes – 2 cells; after meiosis I

-b. Early spermatids – 4 cells; round; haploid

4. Spermiogenesis – spermatids become sperm (spermatozoon)

5. Sperm – characteristics

-a. Head – almost entirely the nucleus

-b. Acrosome – lysosome like; hydrolytic enzymes

-c. Midpiece – contains mitochondria; for tail

-d. Tail – flagellum; mobility

6. Sustentacular cells (Sertoli) – from basal lamina to lumen

-a. Tight junctions – unbroken barrier; two compartments

-b. Basal compartment – cells that haven’t undergone meiosis

-c. Adluminal compartment – cells undergoing meiosis

-d. Blood testis barrier – protect genetically different cells; immune

-e. Other functions – nourish and chemically regulate spermatogenesis

7. Testicular fluid – androgens and metabolic acid; transport medium

8. Duration – spermatogenesis takes about 70 days

9. Epididymis – sperm further mature; swimming ability

Brain-testicular axis

1. Brain-testicular axis – hypothalamus, ant. pituitary, testes

2. GnRH – hypothalamus; anterior pituitary; release LH and FSH

3. LH (ICSH) – interstitial cells; make more testosterone

4. FSH – causes sustenticular cells to release androgen binding protein

-a. ABP – causes spermatogenic cells to bind, concentrate testosterone

5. Testosterone – promotes spermatogenesis

6. Feedback – GnRH inhibited by high levels of testosterone

-a. Inhibin – protein; Sertoli cells; ↑ sperm, ↑ inhibin, ↓ GnRH

8. Puberty – GnRH inhibiting levels keep rising; reach adult levels

9. Prenatal development – high levels of testosterone; repro structures

10. Maintenance – in adults for sperm production; repro no atrophy

Testosterone: other effects

1. Puberty – testosterone reaches adult levels

2. Spermatogenesis – causes this

3. Reproductive organs – ducts, glands, and penis; adult size, function

4. Male secondary sex characteristics – nonreproductive organ changes

-a. Hair growth – face, axillary, and pubic; chest and other body areas

-b. Larynx enlarges – voice deepens

-c. Skin – thickens and becomes oily

-d. Somatic effects – bone and muscle growth

5. Basal metabolic rate – also increases due to testosterone

6. Libido – important in sex drive in both men and women

FEMALE REPRODUCTIVE SYSTEM: ANATOMY

Ovary

1. Ovary – female gonad; flank uterus; 3 cm long; almond shaped

2. Ligaments – support ovary; other reproductive structures

-a. Broad ligament – peritoneal fold; supports ovaries; uterus, and tubes

-b. Ovarian ligament – medially to the uterus

-c. Suspensory ligament – laterally to abdominal wall; broad ligament

-d. Mesovarium – part of broad ligament

3. Ovarian artery – and ovarian branch of uterine; suspensory ligament

4. Tunica albuginea – fibrous capsule; covered by germinal epithelium

5. Germinal epithelium – cuboidal cells; continuous with peritoneum

6. Cortex – outer; well vascularized connective tissue; gametes form

7. Medulla – inner layer; larger blood vessels and nerves

8. Ovarian follicles – sac like structures found in the cortex

Ovarian follicles

1. Oocyte – the immature egg

2. Surrounding cells – different names; depending on number of layers

-a. Follicular cells – one layer of cells present

-b. Granulosa cells – when more than one layer present

3. Primordial follicle – 1 layer, squamous like cells surround oocyte

4. Primary follicle - two layers of cuboid/columnar granulose cells

5. Secondary follicle – an antrum appears between oocyte and granulosa

-a. Antrum – fluid filled space

6. Vesicular (Graafian) follicle – oocyte; stalk of granulosa cells

7. Ovulation – ripened follicle ejects its oocyte; every month

8. Corpus luteum – remnants of ruptured follicle

Uterine (fallopian) tubes or oviduct

1. Function – picks up ovulated oocyte; fertilization

2. Isthmus – constricted region close to where it enters the uterus

3. Ampulla – distal end; expands as it curves around ovary

4. Infundibulum – open funnel shaped end of the ampulla

5. Fimbriae – ciliated finger like projections from the infundibulum

6. Oocyte transport – several mechanisms

-a. Cilia – ciliated simple columnar; fimbriae; beat

-b. Secretions – nonciliated cells with microvilli

-c. Peristalsis – smooth muscle layers of the uterine tube

7. Mesosalpinx – part of broad ligament; suspends uterine tube

8. Pathologies – disconnections between uterine tube and ovary

-a. Ectopic pregnancy – in peritoneal cavity; naturally abort; bleeding

-b. Pelvic inflammatory disease –peritoneal infection; infertility

Uterus: gross anatomy

1. Location – pelvic cavity; anterior, rectum; inferior- superior bladder

2. Function – receive, retain, and nourish fertilized ovum

3. Body – the major part

4. Fundus – rounded part; superior to uterine tubes

5. Isthmus – narrowing between body and cervix

6. Cervix – narrow neck; projects into the vagina

-a. Cervical canal – the cavity of the cervix

-b. Internal os – opening to the uterus

-c. External os – opening to the vagina

7. Uterine support – several ligaments

-a. Round – anterior body wall and labia majora

-b. Mesometrium – part of the broad ligament; lateral support

-c. Uterosacral – from uterus to sacrum

-d. Lateral cervical (cardinal) – cervix, superior vagina to pelvis

8. Pathologies – several; two important

-a. Cervical cancer – inflammatory history; Pap smear; hysterectomy

-b. Uterine prolapse – birth; torn ligaments; protrudes through vagina

Uterine wall: histology

1. Perimetrium – outer most; visceral peritoneum

2. Myometrium – bulky middle layer of smooth muscle layers

3. Endometrium – mucosal lining of uterus

-a. Stratum functionalis – simple columnar; thick lamina propria; shed

-b. Stratum basalis – thinner; forms new functionalis

4. Vascular supply – related to monthly changes

-a. Uterine arteries – branch from internal iliac

-b. Arcuate arteries – branches in the myometrium

-c. Radial branches – into endometrium

-d. Straight arteries – into stratum basalis

-e. Spiral (coiled) arteries – into stratum functionalis; de, - regenerate

Vagina

1. Copulatory organ – thin walled tube; between rectum, bladder

2. Birth canal – passageway for delivery

3. Vaginal layers – three of them

-a. Adventitia – outer fibroelastic layer

-b. Muscularis – middle layer of smooth muscle

-c. Mucosa – stratified squamous epithelium; rugae; dendritic cells

4. Mucus – none produced by vagina; cervical glands above

5. Acid mantle – epithelial cells, glycogen; bacteria ferment, lactic acid

-a. Protection – from infection; hostile to sperm

6. Vaginal orifice – opening to exterior

7. Hymen – mucosa near the orifice form a partial partition

8. Vaginal fornices – recesses of vagina around cervix

Vulva: External genitalia

1. Mons pubis – fatty rounded area over pubic symphysis; hair

2. Labia majora – 2 elongated fatty folds; male scrotum

3. Labia minora – 2 thin hairless skin folds

4. Vestibule – recess; between labia minora; vaginal, urethral openings

5. Greater vestibular gland – opening in vestibule; lubricant

-a. Bulbourethral gland – homologous to this

-b. Bartholin gland – alternative name

6. Lesser vestibular glands – number of them; also provide lubricant

7. Paraurethral glands – paired mucus glands; near urethral orifice

-a. Prostate – homologous to this

-b. Skene glands – another name for this

8. Clitoris –anterior to vestibule; small protrusion; erectile tissue

-a. Erectile tissue – becomes engorged with blood when aroused

-b. Prepuce – hood; labia minora

9. Vestibular bulbs – s.c. erectile tissue; deep to labia majora

Mammary glands

1. Sweat glands – developmentally; modified; integumentary system

2. Breast – rounded skin covered structures; contain mammary glands

3. Areola – ring of pigmented skin; below center of each breast

-a. Sebaceous gland – rough; sebum reduces chapping, cracking skin

4. Nipple – protruding structures in the middle of each areola

-a. Smooth muscle – nipple becomes erect; tactile stimulation; cold

5. Lobes – 15 to 25; radiate around and open at the nipple

6. Suspensory ligament – connective tissue; anchors lobes

7. Lobules – smaller subdivisions of each lobe

8. Alveoli – compound alveolar glands; produce milk

9. Lactiferous duct – milk from alveoli to nipple

10. Lactiferous sinus – deep to areola; widening lact. duct; accumulate

11. Pregnancy – last trimester is when the above structures are seen

12. Breast cancer – most common malignancy in U.S. women

-a. Risk factor – family history, early menses, late menopause

-b. Diagnosis – self examination; mammogram

-c. Treatment – mastectomy, lumpectomy, chemo, radiation

FEMALE REPRODUCTIVE SYSTEM: PHYSIOLOGY

Oogenesis

1. Oogonia – in fetus; mitosis; growth

2. Primordial follicle – about 400,000; at birth

-a. Primary oocyte – in prophase I of meiosis; stays there

-b. Follicular cells – flattened cells which surround primary oocyte

3. Vesicular follicle – meiosis I is complete; begins meiosis II

-a. Secondary oocyte – haploid; most cytoplasm; arrested metaphase II

-b. First polar body – little cytoplasm; may do meiosis II; degenerate

4. Ovulation – with secondary oocyte in metaphase II

5. Fertilization – egg must be penetrated by sperm; finishes meiosis II

-a. Ovum – larger cell with most of the cytoplasm

-b. Second polar body – smaller cell; degenerates

Ovarian cycle: Follicular phase

1. Primordial to primary follicle – several begin; only one completes

-a. Activation – follicular squamous to cuboidal; 1^◦oocyte enlarges

2. Primary to secondary follicle

-a. Granulosa cells – cells surrounding primary oocyte now stratified

-b. Theca folliculi – layer of connective tissue around follicle

-c. Estrogen – theca cells, androgens; granulosa convert to estrogen

-d. Zona pellucida – membrane around oocyte; glycoproteins

-e. Antrum – fluid filled cavity around oocyte; now secondary follicle

3. Secondary to vesicular (Graafian) follicle

-a. Stalk – oocyte isolated on it; on one side of the follicle

-b. Corona radiate – capsule of granulosa cells still around oocyte

-c. Primary oocyte – complete meiosis I; secondary oocyte 1^st polar body

-d. Secondary oocyte – arrested in metaphase II

Ovarian cycle: ovulation

1. Ovulation – ovary wall ruptures; secondary oocyte released

2. Corona radiata – still surrounds secondary oocyte

3. LH – provides the stimulus for ovulation

Ovarian cycle: luteal phase

1. Corpus hemorrhagicum – atrum fills with clotted blood; reabsorbed

2. Corpus luteum – remaing granulosa and theca; new endocrine organ

-a. Progesterone – produced by corpus luteum

-b. Estrogen – produced by corpus luteum

3. Preganancy – corpus luteum remains 3 months; until placenta

4. Corpus albicans – no pregnancy; degenerates; small white scar

Ovarian cycle: establishing

1. Childhood – low estrogen released; feedback inhibition GnRH

2. Puberty – it approaches, hypothalamus ↓ sensitive estrogen feedback

3. GnRH – released in rhythmic patterns

4. Gonadotropins – release from pituitary is stimulated

5. Anovulatory period – gonadotropins levels ↑ few years; no ovulation

6. Menarche – first period; 3 years before regular and ovulatory

Ovarian cycle: hormonal interactions

1. GnRH – released by hypothalamus (day one)

2. Gonadotropins – blood level rise; stimulate follicle

-a. LH – causes thecal cell to release androgens

-b. FSH – causes granulosa cells to convert androgens to estrogens

3. Negative feedback – rising estrogen; pituitary ↓release gonadotropin

4. Positive feedback – very high estrogen; stimulates anterior pituitary

5. Gonatotropin surge – from positive feedback; mostly LH

6. Oocyte – effects of the LH surge are

-a. Primary oocyte – finishes meiosis I

-b. Secondary oocyte – through meiosis II up to metaphase II

-c. Ovulation – protrusion; no blood flow; weakens; ruptures; day 15

-d. Decrease in estrogen – damage to structures producing in

7. Corpus luteum – LH; from follicle left over; note name

8. Negative inhibition – estrogen, progesterone inhibit

-a. Inhibin – from corpus luteum; enhances feedback inhibition

9. Corpus luteum – fate can vary

-a. Implantation – of embryo; releases hormone to maintain c. l.

-b. Degeneration – caused by low LH, FSH; estrogen, progesterone ↓

10. Ovarian hormones – low level, day 28, LH and FSH released

Uterine (menstrual) cycle

1. Menstrual phase – days 1 through 5

-a. Functional layer – detaches; blood; out vagina

-b. Hormone level – initially, ovarian and gonadotropin levels lowest

-c. FSH – begin to rise; no feedback inhibition ovarian hormones

2. Proliferation phase – day 6 through 14

-a. Functional layer – estrogen causes basal layer to generate new one

-b. Uterine glands – enlarge and increase in number

-c. Spiral arteries – increase; endometrium becomes vascularized

-d. Progesterone receptors – estrogen increases their numbers

-e. Cervical mucus – thick & sticky; thin & crystalline; sperm move

3. Secretory phase (beginning) – days 15 through 28

-a. Implantation – prepared for

-b. Progesterone – acts on estrogen primed cells; glands and arteries

-c. Spiral arteries – more elaborate; coil more tightly

-d. Uterine glands – enlarge; glycoprotein; embryo before implantation

-e. Negative feedback – high estrogen; low LH

-f. Implantation – releases hormones to maintain corpus luteum

-g. Corpus luteum – degenerates if no implantation

4. Secretory phase (end) – approaching day 28

-a. Progesterone levels – fall due to corpus luteum degeneration

-b. Spiral arteries – kink and go into spasms

-c. Endometrial cells – deprived of oxygen; die; self digest

-d. Menstrual flow – spiral arteries constrict; fragment; slough off

Estrogen: extrauterine effects

1. Estrogen – similar effect to testosterone

2. Gamete production – oocyte and follicle maturation

3. Reproductive tract – maturation of ducts, external genitalia

4. Puberty growth spurts – bone growth

5. Secondary sex characteristics – as testosterone does in boys

-a. Breast growth – get larger

-b. Subcutaneous fat deposits – hips and breast area

-c. Pelvis – widened and lightening; child birth

-d Hair growth – in axillary and pubic areas

Progesterone: extrauterine effects

1. Uterine mobility – decreases this during pregnancy

2. Lactation – prepares breast for this

Female sexual response

1. Excitement – similar to male erection in some ways

-a. Blood engorgement – clitoris, vaginal mucosa, and breast

-b. Nipples – become erect

-c. Vestibular gland – secrete to lubricate vagina for penetration

2. Stimuli – touch or psychological

3. Orgasm – muscle tension, pulse, heart rate; uterus contract; pleasure

-a. Refractory period – not; as many orgasm in one experience