Reproduction and Development (Physio 26 Gecko) PDF

Chapter 26 -- Reproduction and Development **[26.1 Sex Determination]** [1. Describe the role of sex chromosomes in sex determination] - Sperm determines the sex - Sperm either gives the X or the Y determines gender - 1 pair of sex chromosomes: XX or XY - Determine genetic sex...

Chapter 26 -- Reproduction and Development **[26.1 Sex Determination]** [1. Describe the role of sex chromosomes in sex determination] - Sperm determines the sex - Sperm either gives the X or the Y determines gender - 1 pair of sex chromosomes: XX or XY - Determine genetic sex - Y is essential for male reproductive development - Autosomal cells = somatic cells that contain autosomes (22 pairs of non-sex chromosomes) - Gametes are haploid (egg & sperm cells) - Diploid cells = any cell with two complete sets of chromosomes - 1 set from each parent 46 total - Diploid refers to the NUMBER of chromosomes (46 total) or 2n - Autosomal cells = specific subset of diploid cells that EXCLUDE sex cells/gametes [2. Describe the bipotential reproductive structures of the early embryo] - Bipotential = can become male / female depending on what chemicals / hormones are present - SRY gene makes SRY protein / testes determining factor converts bipotential gonads into testes - SRY gene on Y chromosome Male - Absence of SRY gene female [3. Diagram the processes of sexual differentiation in male and female embryonic development] - Male -- (testosterone & AMH present) - **Gonadal cortex regresses** - **Gonadal medulla forms testis** - Wolffian duct forms epididymis, vas deferens, & seminal vesicle (if testosterone present) - **Leydig cells / interstitial cells** secrete testosterone converts wolffian duct into male accessory structures - Mullerian duct regresses due to **[Anit-mullerian hormone]** from the testicular **Sertoli cells**. (**AMH** present) - **DHT** develops prostate and external genitalia - Female -- (testosterone & AMH absent) - **Gonadal cortex forms ovary** - **Gonadal medulla regresses** - Wolffian regresses (if testosterone is absent) - Mullerian duct becomes Fallopian tube, uterus, cervix, and upper half of vagina (**AMH** absent) A diagram of a cell Description automatically generated [4. Describe and compare male and female gametogenesis] - Begins in utero - **Male Gametogenesis** - Haven't progressed past mitosis at birth - Germ cells are spermatogonia - Not dividing until puberty - Mitosis resumes at puberty - Resting pool of Spermatogonia - Continuous production of sperm from puberty death - **Female Gametogenesis** - Oogonia completes mitotic stage before birth - No resting pool of oogonia - Born with all eggs that will be produced - Begin 1^st^ steps of meiosis and arrest until puberty (primary oocytes) - Mature once a month at puberty until menopause - Primary oocytes if selected divide to become egg (secondary oocyte) and 1^st^ polar body - Ovulation = release of the secondary oocyte - If fertilization second meiotic division before the zygotic program - Secondary oocyte divides into mature gamete & 2^nd^ polar body  \*\*\*notice the **first step of meiosis** creates [primary spermatocytes and oocytes]. The **first division in meiosis** creates [2 identical spermatocytes] in men & [1 large secondary oocyte (egg)] in females + 1^st^ polar body (to get rid of extra chromosomes) **Second meiotic division** creates [haploid spermatids] that mature into sperm. In females, the [division does not complete unless the egg is fertilized]. **[26.2 Basic Patterns of Reproduction]** **5. Diagram the common hormonal control and feedback pathways for reproductive function** - Both sexes produce androgens and estrogens - Androgens = dominant in males - Testosterone from testis - Estrogens = dominant in females - Ovary produces estrogens, progestins, and androgens - **Aromatase** = enzyme that converts androgens to estrogens - Positive & negative feedback pathways A diagram of a steroid hormone Description automatically generated \***sex steroid hormones (controlled by LH release)**: androgens, estrogens, & progesterone. Aromatase converts androgens to estrogens. Inhibin inhibits secretion of FSH, and activin stimulates FSH secretion. \*Gonadal steroids typically suppress secretion of GnRH, FSH, and LH. EXCEPT if estrogen levels rise above threshold for 36 hours changes to positive feedback stimulates GnRH release [6. Explain the significance of pulsatile GnRH secretion] - From hypothalamus - Controls secretion of 2 anterior pituitary hormones - **FSH** = regulates gametogenesis in gonads - Inhibin INHIBIT FSH secretion - Activins stimulate FSH secretion & promote spermatogenesis, oocyte maturation, & development of embryonic nervous system - **LH** = controls production of sex hormones - Pulsatile GnRH release - Pulse generator involved in sexual maturity - After puberty, tonic GnRH release occurs in small pulses every 1-3 hours from a region in the hypothalamus called a **pulse generator**. [7. Describe some environmental factors that influence reproductive physiology] - In women: stress, nutrition, daylight, & environmental estrogens - In men: environmental estrogens **[26.3 Male Reproduction]** [8. Know the internal and external anatomy of the adult male reproductive and accessory structures & their function] - Male accessory glands contribute to semen - Prostate gland - Seminal vesicles - Bulbourethral (Cowper's) gland - Testes produce sperm & hormones - Leydig / interstitial cells produce testosterone - Sperm is produced in the seminiferous tubule 9\. Diagram the process of spermatogenesis - Spermatids = immature form of sperm undergo transformation into sperm - Need acrosome (head piece) formation for fertilization - Spermatogenesis requires gonadotropins and testosterone 10\. Explain the hormonal control of spermatogenesis  Step by step process from old book ABP is how testosterone travels in the blood \*Sertoli cells regulate sperm development, produce inhibin, activin, growth factors, enzymes, and androgen-binding protein \*Leydig cells / interstitial cells produce 95% of male's testosterone... other 5% comes from adrenal cortex A diagram of a cell Description automatically generated 11\. Describe the primary and secondary sex characteristics of the male and the hormones that influence their development - Androgens influence primary and secondary sex characteristics - Primary: internal organs & genitalia - Secondary: traits at puberty (hair, voice, libido, muscles) **[26.4 Female Reproduction]** [12. Know the internal and external anatomy of the adult female reproductive and accessory structures and give the functions of each. ] - Won't be asked this [13. Diagram and give timeline for follicular development from primordial follicle to corpus albicans] - Organization of ovary - Outer connective tissue & inner connective tissue (stroma) - Cortex contains follicles - Medulla blood vessels and nerves - Primordial follicle - Primary oocyte surrounded by granulosa cell - Will undergo atresia if not selected for maturation - Primary follicles - Primary oocyte grows - Granulosa cells divide - Secondary follicles - Follicles grow larger (multiplying granulosa cells) - Theca begins to form - Some fail and become atretic (apoptosis) - Tertiary follicle - Formation of a large fluid filled cavity (antrum) - A follicle that **remains from pool???** becomes the dominant follicle - Releases egg  **\*Good pic but don't memorize** A diagram of cell growth Description automatically generated 14\. SKIP [15. Diagram the ovarian and uterine stages of the menstrual cycle] Menstrual cycle = ovarian cycle + uterine cycle - Ovarian cycle & Uterine cycle occur simultaneously just in different locations - Ovarian cycle (follicle) - Follicular phase \~ follicular growth - Early follicular phase: - FSH grows the tertiary follicles - Granulosa cells and theca produce steroid hormones - Estrogen blocks FSH and LH - AMH [Anit-mullerian hormone,] prevents development of other follicles in this cycle - Endometrium proliferates because of estrogen - Mid -- to -- late follicular phase - High estrogen becomes positive feedback - LH and FSH surge - Uterus prepares for implantation, endometrium thickens - Ovulation \~ release egg from follicle - Inflammatory reaction attracts leukocytes that secrete prostaglandins - Mature follicle secretes matrix metalloproteinases (MMPs) - Follicle ruptures, releasing mature oocyte - Luteal phase \~ ruptured follicle become corpus leutum - Early -- to -- mid luteal phase - Granulosa and theca cells differentiate into luteal cells - Luteal cells secrete inhibin, progesterone, and estrogen - Negative feedback on hypothalamus - Endometrium prepares for implantation - Deposits lipids and glycogen increase in endometrial cells - Provides nutrients for embryo while placenta develops - Cervical mucus thickens - Late luteal phase & Menstruation - No pregnancy = corpus luteum degenerates into corpus albicans - Progesterone & estrogen levels drop and FSH and LH are secreted - Endometrium sloughs off menstruation Early follicular phase mid-late follicular phase Ovulation Early / mid luteal phase Late luteal phase & menstruation - Uterine cycle (uterine cycle) - Meneses - Proliferative phase - Secretory phase  Higher frequency in follicular phase A diagram of human body parts Description automatically generated  **Estrogen = causes uterine lining to build up** **Progesterone = maintains the uterine lining** - Progesterone is produced by the corpus luteum **Inhibin = selectively inhibits FSH** - FSH recruits additional follicles **LH = causes ovulation** **16. Relate the hormonal control and feedback patterns of the menstrual cycle to different stages of the ovarian and uterine cycles.** - Last diagram from above! [17. Describe the secondary sex characteristics of the female and the hormones that influence their development] - **Primary sex characteristics** are controlled by **estrogens** - **Secondary sex characteristics** controlled by **estrogens** - Breast development - Fat distributions (hips/upper thighs) - **Secondary sex characteristics** controlled by **androgens** - Pubic/axillary hair - Libido **\*\*\*secondary characteristics in males = only androgens** **\*\*\*secondary characteristics in females = both estrogen & androgens** **[26.5 Procreation]** 18\. SKIP 19\. Explain currently available contraceptive methods A white paper with black text Description automatically generated