. Biology of Reproduction, lecture on Adult Female Reproductive Systems

Biology of Reproduction

Fall 1998

text: Human Reproductive Biology 2nd Edition - R.E. Jones: Read pages 26-62 for this lecture

VII. Adult Female 			back to VI. Feedback

	A. Reproductive Anatomy

		1. Uterus

		2. Fallopian Tube or Oviduct

		3. Broad ligament

		4. Ovary

			a. Surface Epithelium

			b. Cortex (outer layer)

				i. primary oocytes
				   (female germ cells, found within follicles)

				ii. some vertebrates have germinal bed

					(1) for continued production of 1o oocytes

		3. Medulla (inner layer)

			a. arteries, veins, nerves

		4. Hilus

	B. The Follicle

		1. Follicular Wall

		2. Oocyte

		3. Primordial Follicle   50 mm diameter

			a. 1o oocyte

			b. membrana granulosa

			c. zona pellucida

		4. Primary Follicle

			a. granulosa becomes cuboidal

			b. gains Theca

				i. connective tissue

				ii. invaded by blood vessels immediately

		5. Secondary Follicle

			a. up to six layer granulosa

				i. cell division = mitosis

		6. Tertiary Follicle   25mm diameter

			a. Theca externa = connective tissue

			b. Theca interna

				i. glandular

			c. 2-3 layers of granulosa

			d. Antral fluid in Antrum

				i. filtrate of blood from capillaries in the Theca

			e. corona radiata

			f. cumulus oophorus

		7. Follicular Atresia

			a. a female (any mammal) is born with all
			   the oocytes she'll ever have

				i. human embryo has 3.5 million follicles

				ii. fish, amphibians, reptiles & birds
				    have germinal beds

					(1) \ can produce 1o oocytes throught life

						(a) produced mitotically,
						    mature to ova meiotically

			b. most follicles are lost by atresia

				i. can happen at any stage

				ii. more prevalent at later, larger stages

					(1) atresia often occurs as a result of supporting
					    (steroidally) the follicle which will ovulate 

			c. follicular selection

				i. very few oocytes are ovulated

					(1) larger follicles,
					    with a greater blood supply,
					    get a greater share of gonadotropins

						(a) \ grow faster

					(2) which oocytes begin to grow are probably
					    controlled by the hypothalamus
					    via the vagus nerve

				ii. many follicles grow and then die

			d. those that grow and do not ovulate help make
			   steroids (E2) for positive feedback

		8. Steroid Production

			a. one of the 1o functions of follicle cells

			b. Estrogens:
			    any compound that causes the uterus to grow

				i. 3 natural estrogens

					(1) E2 = estradiol-17b

					(2) E1 = estrone

					(3) E3 = estriol

			c. Progestogens:
			      any compound that allows embryo
			      to implant/grow in the uterus

				i. P (progesterone)  (peripheral)

				ii. in the brain

					(1) THP = allopregnanolone = 3a-OH-DHP

					(2) Preg-S = pregnenolone sulfate

			d. Androgens:
			     any compound which will
				 stimulate growth of the seminal vesicles

				i. potent: most common in men

					(1) T = testerone

					(2)  DHT = dihydrotestosterone

				ii. weak: most common in women

					(1) DHEA = dehydroepiandosterone

					(2) androstenedione

			e. steroidogenesis







				     DHEA ® androstenedione
						÷ö  æ
					 T		             E1
				         ¯ ø    ÷ö
            ø  ÷ö
				 	 E3	       E2

				i. D5 pathway = ® = main follicular source of steroids from the ovay

					(1) Tertiary follicles

		Theca			  	                Granulosa

 cholesterol ®  ® pregnenolone
		   D5 	 ÷
      ÷           transported by diffusion
	androstenedione- - - - - - - - - - - - - - - - - ®




									      ¯ *FSH

	*required							E2

		9. Corpus Luteum (yellow body)

			a. formed after ovulation

			b. Luteinization

				i. product of LH surge (name of LH)

					(1) begins just before ovulation

				ii. theca thickens

				iii. granulosa divides (mitosis)

					(1) very fast

				iv. these cells now = luteal cells

				v. steroidogenic - D4 pathway = ®


				pregnenolone ® ® ® ® ® ® Progesterone

				       ¯					      ¯

				17-OH-preg  	   		          17-OH-P

				      ¯					              ¯

				DHEA ® ® ® ® ® ® ® ® androstenedione

		Theca			    	            Luteal cells (granulosa)

		 D5					    cholesterol ® pregnenolone
									                ¯ D4
								                 ÷    ¯ 	     
								    blood           ¯ (small amt)
								     (most)        17-OH-P


										           E1 ® E2

				vi. 3o follicle = 1/4 P : 3/4 E2
					(1) E2 stimulates LH surge via + feedback

					(1) \ luteinization

				vii. Corpus luteum = 2/3 P : 1/3 E2

		10. Follicles (summary)			In a woman (age 16-25)/ovary

			a. primordial	® 1o ® 2o			   79,500	    3,300

			b. 3o or antral: three categories

				i. resting						
										  		       } 47
				ii. ripe

				iii. graafian or vesicular				10

			c. Pre-ovulatory						   0 - 1

	C. Oocyte Maturation

		1. Primary Oocyte

			a. dipoid = 2N

				i. humans have 46 chromosomes

				ii. = 23 homologous pairs

					(1) each pair includes one chromosome contributed
					    from maternal and 1 from paternal parent 

				iii. arrested in prophase of meiosis I

			b. 99.9% of ovarian oocytes

		2. Reduction division (finish Meiosis I)

			a. equal division of homologous pairs,
			    but unequal division of cytoplasm

				i. only occurs in germ cells

			b. first polar body

				i. haploid = 1N

		3. Secondary Oocyte

			a. haploid

			b. ovulated as it begins Meiosis II ® then arrested

		4. Meiosis II

			a. = mitosis with 1N chromosomes

			b. stimulated by sperm penetration

		5. 2nd polar body

		6. Ootid

	D. Ovulation

		1. LH ® Oocyte maturation
			 a. Ovulation

				i. hyperemia

				ii. stigma formation

				iii. ovulation cone    (mammals)

					(1) LH ® E2 ® surface epithelium
                                      and/or thecal cells ® collagenase

						(a) inflammatory response?
						   smooth muscle contraction?

				iv. oocyte - cumulous oophorus attachment breaks

				v. fluid oozes out through the open stigma

				vi. oocyte flows out with antral fluid

				vii. oocyte caught by fimbriated extremity
				    of the fallopian tube

	E. Fallopian Tube = Oviduct = Uterine Tube

		1. Ostium = opening

		2. Frimbria(e) = fingers

		3. Infundibulum

		4. Ampulla

			a. ampullary-isthmic junction

				i. fertilization ususally takes place here

		5. Isthmus

		6. Intramural

		7. Uterotubal junction

		8. Cross-section

			a. Serosa (squamous epithelium)

			b. Smooth Muscle

				i. Longitudinal Layer

				ii. Circular Layer

				iii. each cell contracts rhythmically
				     in its own phase
					 - out of phase: no function
					   - in phase: peristaltic contraction

					(1) contractions integrated = coordinated

					(2) directional - wave of contraction
					    squeezes all the way down the tube

			c. Mucosa
			  (mostly connective tissue underlying epithelium)

			d. Ciliated columnar epithelium

				i. Goblet cells (mucus producing)

	F. Uterus

		1. myometrium

			a. smooth muscle

				i. inner circular
				outer longitudinal

		2. Endometrium

			a. epithelial cells

			b. uterine glands

			c. vascularity

		3. Cervix

			a. cervical canal leads to vagina

				ii. cervical os 

					(1) internal, external & opening

	G. Endometrium

		1. Uterine glands

			a. so many you cant see the mucosa

			b. E2 causes uterine gland growth, hyperemia

				i. mediated by growth factors (EGF's, IGF's)

			c. P + E2 ® secretion

				i. uteroglobin (protein)

			d. withdrawl of P + E2 ® death of endometrium

				i. sloughing

VIII. Adult Male