NFS 203 Lecture 2: NFS 203 Ch 2

5 Pages
Unlock Document

Drexel University
Nutrition & Food Science
NFS 203
Beth Leonberg

NFS 203 Ch 2 Infecundity - Biological inability to have kids after 1 yr unprotected sex Fecundity - Biological ability to have kids Fertility - Actual production of kids Fetus - 8 weeks after conception until birth Subfertile - Reduced level of fertility w/ long time to conception (over 12 months) of repeated pregnancy losses - The capacity of one individual can make up for the diminished potential of the other - Can be diminished via diet, weight and lifestyle improvements - Women who have 2-3 miscarriages - Men who have sperm abnormalities - Women who ovulate infrequently Chances of Pregnancy - 20-25% for healthy couples - 30-50% conceptions lost by resorption into the uterine wall within the first 6 weeks after conception - 9% lost by miscarriage in first 20 weeks of pregnancy - Causes: - Defect in fetus - Material infection - Structural abnormalities of uterus - Endocrine or immunological disturbances Menstrual cycle - First half: follicular phase - Estrogen stimulates hypothalamus to secrete GnRH - GnRH stimulates pituitary gland to release FSH and LH - FSH prompts growth of follicles, stimulates estrogen production within the follicles - LH causes secretion of progesterone which prompt uterine wall to store glycogen and nutrients - Blood levels of FSH and LH are highest prior to ovulation (day 14) and the LH surge causes the release of an ovum from a follicle for ovulation - Second half: luteal phase - After ovulation - Corpus luteum from the original follicle that released the ovum secretes progesterone and estrogen which inhibit production of GNRH - Inhibition of GnRH stops release of FSH and LH and without it, ova within follicles dont mature or release - If ovum isnt fertilized, the hormones of the corpus luteum decline and the GnRH is able to stimulate the release of FSH and LH - Decreased progesterone and estrogen levels cause menstrual flow - Prostaglandins is produced by the uterus and can cause cramps - If ovum is fertilized, it will go to the uterus in 8-10 days - Corpus luteum continues to produce estrogen and progesterone and ceases function in first few months of pregnancy Male Reproduction - Levels of GnRH signal release of FSH and LH which trigger the production of testosterone - Testosterone and androgens stimulate maturation of sperm which is stored in the epididymis - Semen: mix of sperm, secretions of the testes, prostate and seminal vesicle Disruptions in Fertility 1) Adverse nutritional exposure 2) Severe stress 3) Infection 4) Structural problems 5) Chromosome abnormalities Nutrient & caloric intake and body fat affect fertility by: 1) Altering environment for developing sperm and eggs 2) Modifying hormone levels Body Fat and Fertility - Leptin: - Protein that decreases appetite, increases energy expenditure, and stimulates gonadotropin secretion - Elevated by high body fat - Reduced by low body fat Obesity - makes you subfertile with higher levels of estrogen, androgen and leptin - Hormonal changes favor irregular periods, ovulatory failure, anovulatory cycles (menstural cycle where ovulation doesnt occur) , and amenorrhea (absence of menstrual cycle) - Obesity in men is linked to lower testosterone and higher estrogen and leptin which can cause reduced sperm and erectile dysfunction - Increased risk of neural tube defects Low Fat - In an adolescant: - related to delayed menstruation and reduced fertility - In an adult - related to delayed conception, amenorrhea, lower libido, reduced sperm - Risk of early delivery Weight Loss in Normal Weight People - Weight loss exceeding 10-15% weight decreases estrogen, LH, FSH - Results: - Hypothalamic Amenorrhea (weight related amenorrhea) - anovulatory cycle - short/ absent luteal phase - Fixes to improve fertility: - Hormones return to normal when you restore 95% previous weight - Clomid if weight is gained - Use of GnRH, FSH and hormones Nutrients - Antioxidant
More Less

Related notes for NFS 203

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.