OB Chapter 3: Genetics, Conception, and Reproductive System

Genes

Formed by DNA and Proteins

Genotype

A persons genetic makeup

phenotype

The way in which these genes are outwardly expressed in physical traits

Advances in genetics

• the study of heredity

• focuses on single genes

genomics

• study of genes and their function and related to technology

• focuses on all genes

Recessive Genes

genetic disease and disorders are related defective__________

Autosomal-recessive

One defective gene carries disorders but doesn’t mean person has disorder

• Ex. Sickle Cell, Cystic Fibrosis, Thalassemia, Tay-Sachs Disease

Autosomal- Dominant

one or both genes in pair carry defect

• Huntington’s

• Xeroderma Pigmentation

X-linked inheritance

• X chromosome is mutated gene

• Male child mutated x chromosome will have disorders ( recessive→ dominant)

• Male children Y chromosome → father to son only

• Female children mutated X chromosome→ no disease

  • Ex. hemophilia

Genomic Medicine

Medical discipline using genomic information about patient to provide clinical care and outcomes.

• Newborn screenings for inherited diseases

• cell - free circulating DNA (biomarker factor)

• pharmacogenetics

• drug therapy for genetic disease

Genetic Testing

used to identify individuals who carry gene mutation when there is family history of genetic disorder

→ detect changes in embryos

• ex. downs syndrome, hemophilia, Tay-sach’s disease

Risk factors of genetic disorders

Pregnant mother who is over 35 y/o has a little boy and uncle with downs syndrome.

Teratogens

drugs, viruses, and infections that can cause birth defects or death to fetus.

What is teratogenic exposure based on?

length, amount and when exposure occurs

When is the fetus most vulnerable to teratogens?

8 weeks of gestation during organogenesis

Examples of drug teratogens

• alcohol

• ace inhibitors

• Carbamazepine (anticonvulsants)

• cocaine

• warfarin→ abortions and hemorrhaging

Examples of viral teratogens

• Chicken pox

• Rubella

• Syphilis

• Toxoplasmosis

• Zika

• Cytomegalovirus

oogenesis

Anterior pituitary gland secretes FSH hormone which causes the growth of follicles that secrete estrogen that causes the maturing of the ovum

Conception

fertilization of the egg within the outer third of the fallopian tubes

→ oocyte to zygote

1. mature ovum enters fallopian tube

2. sperm travels to fallopian tubes

3. ovum is fertilization

Where is sperm and maturated at?

epididymis

what hormones does the functional layer of the uterus secrete?

estrogen and progesterone which thickens wall

follicular phase

from first day of mensuration + 12-14 days after

Graafian follicle

__________matures due to LH & FSH hormone which produces estrogen

Estrogen peaks

What action causes ovulation to begin which release oocyte

Proliferation phase

• Occurs after mensuration and ends with ovulation

• endometrium becomes thicker

  Hint: part of the endometrial cycle

secretory phase

Occurs after ovulation and ends with mensuration

progesterone secreted from corpus luteum

Hint: part of the endometrial cycle

what is the purpose of glycogen being released from the corpus luteum?

Energy source for blastocyst

What week should all organs of the fetus be formed ?

week 8

The heart is formed by week ___ of gestation and begins to beat by week ___.

three; four

12 weeks ( 9cm/45g)

RBC produced in the liver, plate infusion, sex can be identified, eyelids are fused closed, FHR can be heard with doppler.

16 weeks ( 14cm/200g)

Lanugo on head, Meconium in intestine, teeth begins to form, sucking motions are made w/ the mouth skin transparent

20 weeks (20cm/450g)

Lanugo covers entire body, vernix caseosa covers the body, nails are formed, brown fat begins to develop

24 weeks (30cm/820g)

alveoli form in the lungs and begin to produce surfactant, footprints and fingerprints are forming, respiratory movement detected

28 weeks (37cm/1300g)

eyelids are open, adipose tissue develops rapidly. the respiratory system has developed to a point where gas exchange is possible but lungs are not fully mature.

32 weeks (42cm/2100g)

bones are fully developed. lungs are maturing increased amounts of adipose tissue.

36 weeks (47cm/2900g)

Lanugo begins to disappear. labia majoria and minora are equally prominent. testes are in upper portion of scrotum.

40 weeks (51cm/ 3400g)

fetus is considered full term at 38 weeks all organs and system are fully developed.

what prevents mothers and baby’s blood from mixing?

placenta membranes

placenta, Fetal waste products and CO2 if transferred from fetal blood to _____________ by diffusion

maternal sinuses

glucose, amino acids, and o2 transferred from the maternal blood sinuses by _________

Active transport

what is the functions of progesterone?

• facilitates implantation

• decreases uterine contractility

what are the functions of estrogen?

• enlargement of the breast and uterus

• maturing of graafian follicle

what is the function of hcg hormone?

stimulates the corpus luteum so it will continue to secrete estrogen and progesterone until placenta is mature

• rises rapidly during first trimester

• assessed in pregnancy tests.

what does the HPL (human placental lactogen)functions?

promotes fetal growth by regulating available glucose and stimulates breast development in preparation for lactation

At what week is the placenta fully functional?

8-10 weeks

The __________ inner membrane is developed from embryoblast and its outer membrane is formed by trophoblast. _____________ provides a sterile environment for the fetus.

amniotic sac

what is formed by the amniotic membrane during the first trimester but then if formed by the fetal kidneys during the second and third trimester?

amniotic fluid

what are the functions of amniotic fluid1?

• cushions the fetus from sudden movement

• prevents fetus to adhere to amniotic membranes

• allows fetal freedom of movement

• provides consistent thermal environment

polyhydramnios

excess amount of amniotic fluid

• risk facto for chromosomal, GI, cardiac, neural tube

Oligohydramnios

decreased amount of amniotic fluid

• risk facto for congenital renal problems

the umbilical cord connect the fetus to the placenta and consist of two ________ umbilical vessel and one umbilical _______.

arteries; vein

if there is only one umbilical vein and artery what is the fetus more at risk for ?

cardiac and vascular defects

umbilical arteries carry _________ blood and umbilical veins carry blood

Unoxygenated; oxygenated

How is infertility defined / diagnosed?

inability of conceive after 12 months of unpretected sex.

Male causative factors for infertility include

endocrine issues

• pituitary disease

• hypothalamic disease

• decreased levels of LH, FSH and testosterone

sperm antibodies that react against sperm causing a decrease in sperm motility

blocked structures of the male reproductive system

erectile dysfunction

gonadotoxins include

• Drugs ( chemotheraputics, calcium channel blockers, alcohol and heroin)

• Infections and viruses ( STI’s, mumps, prostatitis

• systemic illness

• Prolonged heat exposure to the testes( hot tubs, tight underwear, frequent cycling)

• pesticides

• radiation

what are the female factors that can lead to infertility

ovulatory dysfunction

• hormonal imbalances

• hyperthyroidism or hypothyroidism

• high levels of prolactin

• menopause before 40

damage to fallopian tubes (related to Pelvic inflammatory disease(PID) or endometriosis

cervical surgeries (cryotherapy)

risk factor for infertility for women include

• autoimmune disorders

• diabetes

• eating disorders / malnutrition

• alcohol

• excessive exercising

• obesity

• older age

• gonadotoxin therapy

diagnostic test for infertility include

• STI screenings

• Hormone test

• semen analysis

• detecting LH surge

• Ovarian reserve testing

a nurse is taking care of a male patient who is at risk for infertility. what information should she be aware of regarding the semen analysis?

• abstain from masturbating 2-3 days

• specimens must be collected with in an hour and taken to facility

• semen analysis includes the checking the volume, concentration, motility and morphology of sperm.

treatment for infertility includes

Male

• hormone therapy

• lifestyle changes

• corticosteroids

• antibodies to clear infections '

• repair hernias

Female

• lifestyle changes

• drug therapy → letrozole, injectable gonadotropins, GnRH pump, bromocriptine and Clomiphene Citrate (clomid)→ stimulates the release of LH FSH to promote ovulation

Artificial insemination

Sperm that has been removed from semen is deposited directly into the cervix or uterus using a plastic catheter

• The sample is collected by masturbation then sperm are separated from the semen and ­prepared for insemination. Sperm can be from partner or donor.

  Reasons for procedure:

• poor cervical mucus production due to previous surgery of the cervix

• anti-sperm antibodies

• decreased amount of sperm

• decreased sperm motility.

Testicular sperm aspiration

Sperm are aspirated or extracted directly from the testicles then it is microinjected into the ­harvested eggs of the female partner.→ intra-cytoplasmic injection.

• had an unsuccessful vasectomy reversal

• have an absence of vas deferens

• have an extremely low sperm count or no sperm in their ejaculated semen.

IVF

oocytes are harvested and fertilization occurs outside the female body in a laboratory.

Zygote intrafallopian ­transfer (ZIFT)

zygote is placed into the fallopian tube via laparoscopy 1 day after the oocyte is retrieved from the woman and IVF is used

Gamete intrafallopian ­transfer (GIFT)

In GIFT, sperm and oocytes are mixed outside the woman’s body and then placed into the fallopian tube via laparoscopy. Fertilization takes place inside the fallopian tube.

This procedure is used when there has been (1) a history of failed infertility treatment for anovulation, (2) unexplained infertility, and (3) low sperm count.

ET

ET is when, through IVF, an embryo is placed in the uterine cavity via a catheter.

Example of fertility condition in which this procedure is used is when the fallopian tubes are blocked