Reproductive System Chapter 22

Introduction Both male and female reproductive systems function to produce and nurture sex cells (gametes) Males- sperm Females- eggs/oocytes

Gametes Most human cells have 46 chromosomes Two each of chromosomes 1-22 Sex chromosomes- XX female, XY male Sperm/egg have 23 chromosomes each Fertilization- joining of one egg and one sperm = 46 chromosomes

Meiosis Producing gametes

Egg/sperm

Sex determination Females can only give an X to her offspring Males can give either an X or a Y

Male reproductive system Primary sex organs (gonads)- testes Accessory sex organs- internal and external

Male reproductive system

Organs Testes, scrotum- sperm and T Epididymis- maturation Vas deferens- storage Urethra- travel through Accessory glands- seminal fluid production Penis- ejaculates sperm

Testes Paired structures within scrotum Sperm production Seminiferous tubules Site of production, contains spermatogenic cells Interstitial (Leydig) cells Between tubules Secrete testosterone

Regulation of testes by anterior pituitary and hypothalamus (LH and FSH) – causes secretion of testosterone and sperm production

Puberty T levels increase Maturation of sperm Secondary sex characteristics Larynx enlarges, vocal folds thicken Muscle/bone development Facial, pubic hair

Anabolic steroids Drugs that have similar effects to testosterone Increase primary and secondary sexual characteristics in the short term Watch Ben Affleck have a ‘roid meltdown (1994): http://www.youtube.com/watch?v=3FvlIwuQBO8

Epididymis/Vas deferens Coiled tubes on top of testes Maturation of sperm Vas deferens Muscular tubes for transporting sperm

Accessory glands Produce other components of semen (semen is not just sperm!) Seminal vesicles- enzymes, nutrients (fructose), neutralizes vaginal secretions Prostate gland- enzymes, neutralizing fluid, help with sperm motility Bulbourethral gland- lubricates, neutralizing fluid (urine)

Penis Multi-functional Sensory nerves convey pleasure

Erection

BP treatment

https://www.youtube.com/watch?v=-XQcnO4iX_U

Female reproductive system

Female reproductive organs Primary (gonads)- ovaries Accessory organs- internal and external All organs specialized to Produce gametes Favorable environment for fetal development Produce sex hormones

Organs Ovaries- produce eggs (at birth), hormones (estrogen/progesterone) Uterine (fallopian) tube- egg passes through, fertilization Uterus- site of fetal development Vagina- receives sperm

Ovaries Paired structure Cortex- compact tissue, contains masses of cells (ovarian follicles)

Uterine (fallopian) tubes Infundibulum with fimbriae Cilia assist in transport of egg Fertilization

Uterus Hollow, muscular structure Site of fetal development Layered Lumen Endometrium Myometrium Perimetrium

External organs Protection Pleasure

Gamete production Monthly cycle Alternates between ovaries Follicular phase- follicle growth in the ovary Ovulation phase- ovary releases egg Luteal phase- corpus luteum secretes hormones to prepare for pregnancy Alternates between ovaries

Follicular Phase Females are born with underdeveloped eggs, lifetime supply FSH stimulates production of a follicle in the ovary Follicle is basically a ball of cells that contains the egg

Ovulation Follicle begins secreting estrogen Positive feedback, increases LH (outside of ovulation, estrogen typically suppresses LH) LH surge causes release of egg

Luteal Phase 2-5 cm in diameter! Produces progesterone Progesterone preps uterus for implantation Lasts for 14 days, if no implantation If implantation occurs, the implanted embryo secretes a hormone that tells the corpus luteum to keep producing progesterone Progesterone inhibits LH

The uterus Has a cycle that corresponds with the ovarian cycle ~28 day cycle, day 1 of cycle corresponds with first day of period Menses- sloughing off of endometrial lining

Ovarian activity Plasma hormonal concentration LH FSH FSH LH Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ovarian activity Plasma hormonal concentration LH FSH FSH LH Regressive corpus luteum Early corpus luteum Developing follicle Mature follicle Ovarian events Corpus albicans Follicular phase Ovulation Luteal phase Days 1 7 14 21 28 Uterine activity Estrogens Plasma hormonal concentration Progesterone Progesterone Estrogens Thickness of endometrium Days 1 3 5 7 9 11 13 15 17 19 21 23 25 27 1 3 Menstruation Proliferative phase Secretory phase Menstruation

Birth control pills prevent pregnancy by maintaining high levels of estrogen and progesterone, which inhibit pituitary gland hormones and mimics pregnancy

Several methods of birth control

Fertilization

https://www.youtube.com/watch?v=_5OvgQW6FG4

Fertilization/Implantation

Assisted Reproductive Technology (ART) Pregnancy via artificial means Infertility affects 1 in 7 couples Ranges from medications to lengthy procedures such as in vitro fertilization (IVF)