Reproductive physiology, anatomy & fetal development

description of the uterus

hollow, muscular, thick-walled organ shaped like an upside-down pear

Uterus funtion

to provide a safe environment for fetal development.

The uterine lining is cyclically prepared by steroid hormones for implantation of the embryo, a process known as nidation. Once the embryo is implanted, the developing fetus is protected until it is expelled.

What are the two major parts of the uterus

corpus and cervix

what is the corpus also known as

the uterine body

what portion of the uterus does the corpus comprise

 **upper two-thirds** (upper triangular portion)

what portion of the uterus does the cervix comprise

the lower third

what is the corpus mainly composed of

smooth muscle layer (myometrium)

what is the cervix also known as

the “neck” of the uterus

what is the name of the structure that is The **rounded uppermost portion** of the corpus that extends above the points of attachment of the fallopian tube

the Fundus

what is the structure called that is the the **elongated portion of the uterus** where the __fallopian tubes enter__

**cornua**

what is the portion of the uterus **between the internal cervical os and the endometrial cavity called**

Isthmus

How does the cervix change after pregnancy

changes from a circular opening of about 3 mm to a transverse slit with irregular edges.

Description of the fallopian tubes

* arise from each side of the uterus and reach almost to the side of the pelvis, where they turn toward the ovaries
* The fallopian tubes link the peritoneal cavity with the uterus and vagina. This linkage increases a woman’s vulnerability to disease processes in the pelvis.

what are the three parts of the fallopian tubes

The **isthmus, the ampulla, and the infundibulum (fimbria)**

Description os the Isthmus

straight and narrow, with a thick muscular wall and an opening (lumen) 2 to 3 mm in diameter (site of tubal ligation)

Description of the Ampulla

comprises the outer two-thirds of the tube.

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**Fertilization of the secondary oocyte by a spermatozoon** usually occurs here.

where does the ampulla end

at the fimbria

description of the fimbria

funnel-like enlargement with many moving fingerlike projections (fimbriae) reaching out to the ovary.

what are the four layers that make up the fallopian tubes

Peritoneum: covers the tube →

Subserous layer: contains the blood and nerve supply → 

muscular layer is responsible for the peristaltic movement of the tube →

The mucosal layer, next to the muscular layer, is composed of ciliated and nonciliated cells, with the number of ciliated cells more abundant at the fimbria.

What are the three function of the fallopian tubes

* Provide transport for the ovum from the ovary to the uterus (transport through the fallopian tubes varies from 3 to 4 days)
* Provide a site for fertilization
* Serve as a warm, moist, nourishing environment for the ovum or zygote (a fertilized egg).

Description of the ovaries

* two almond-shaped glandular structures just below the pelvic brim
* Each ovary weighs 6 to 10 g and is 1.5 to 3 cm wide, 2 to 5 cm long, and 1 to 1.5 cm thick.

what is each ovary maintained in place by

**ovarian, broad, and infundibulopelvic ligaments**

Ovarian ligament description

 the upper border of the round ligament and can alter the position of the ovary so that it can help the fimbria of the fallopian tube “catch” the ovum. 

purpose of the **Infundibulopelvic ligament**

suspends and supports the ovary.

Description of the breast

considered accessories of the reproductive system, are specialized sebaceous glands

what is the nipple composed of

mainly of erectile tissue, which becomes more rigid and prominent during the menstrual cycle, sexual excitement, pregnancy, and lactation.

description of the Areola

pigmented ring surrounding the nipple of breast

Biological functions of the breast

* Provide nourishment and protective maternal antibodies to newborns and infants through the lactation process
* Be a source of pleasurable sexual sensation.

**Follicle stimulating hormone (FSH) function**

Produced by the anterior pituitary during the first half of the menstrual cycle, stimulating the development of the graafian follicle

**Luteinizing hormone (LH) function**

Anterior pituitary hormone responsible for stimulating ovulation and for development of the corpus luteum

**Estrogens**

Estradiol and estrone produced by ovary

**what structure secretes Progesterone**

corpus luteum

when is progesterone found in its greatest amount

during the secretory (luteal or progestational) phase of the menstrual cycle. 

why is Progesterone often called the hormone of pregnancy

its effects on the uterus allow pregnancy to be maintained

what structure produces prostaglandins

cells of the endometrium

what are the two primary types of prostglandins

groups E and F

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* **PGE** relaxes smooth muscles and is a potent vasodilator 
*  **PGF** is a potent vasoconstrictor and increases the contractility of muscles and arteries. 
* Although their primary actions seem antagonistic, their basic regulatory functions in cells are achieved through an intricate pattern of reciprocal events.

Menarche

first period

puberty

* period when reproductive organs **mature**, & one becomes functionally capable of reproduction

period between childhood & __sexual maturity__

menstruation

* periodic uterine bleeding & vaginal discharge of bloody fluid from the nonpregnant uterus 

Menses begins from puberty and usually begins **14 days following ovulation**

what structure is key for the menstrual cycle to occur

the hypothalamus

what does the hypothalamus secrete in the beginning of the reproductive cycle

 gonadotropin-releasing hormones (GnRH)

what does  gonadotropin-releasing hormones (GnRH) do

allows anterior pituitary to secrete FSH and LH

what does FSH stimulate

development of ovarian **graafian follicles & production of estrogen**

Phase 2 in the neurohormonal basis of the female reproductive cycle

**Estrogen levels drop** and hypothalamic GnRH triggers ant. pituitary to release luteinizing hormone (LH)

Phase 3 in the neurohormonal basis of the female reproductive cycle

A marked **surge in LH** (day 13-14 of 28-day cycle) and small peak in estrogen precedes the release of  the ovum from the graafian follicle

at the end of the female reproductive cycle what happens if no fertilization occurs

progesterone & estrogen levels drop, menstruation occurs → the hypothalamus is stimulated to secrete GnRH

what are the 3 parts of the ovarian cycle

follicular phase, luteal phase, ovulation

how long is the ovarian cycle

approx. 28 days

what days of the ovarian cycle does the follicular phase occur

days 1-14 (can vary)

what days of the ovarian cycle does the luteal phase occur

days 15-28

what days of the ovarian cycle does ovulation occur

occurs on day 14 in length of cycle +/- 1-2 days 

what marks the end of the luteal phase

 ends with onset of menses

signs and symptoms that a female is ovulating

1. mid cycle bleeding
2. **mittelschmerz** – mid cycle or ovulation pain (due to estrogen)
3. thin cervical mucus
4. Higher body tension
5. Higher libido

what occurs during the follicular phase

Primordial follicle **matures** under influence of FSH and LH up to the time of ovulation.

what occurs during the luteal phase

Ovum leaves follicle; corpus luteum develops under LH influence and produces high levels of progesterone and low levels of estrogen.

what are the 3 phases of the endometrial cycle

menstrual phase

prolifertice phase

secretory phase

what phase of the endometrial cycle is the endometrium shed

menstrual phase

what days of the cycle does the menstrual phase take place

days 1-6

signs that a female is the menstrual phase

Cervical mucus is scant, viscous, and opaque

what are hormone levels like in the menstrual phase

Estrogen levels are low

what phase of the endometrial phase is the endometrium being built

the proliferative phase

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the Endometrium and myometrium **thickness increases**

what hormone influences the building of the endometrium

estrogen (estrogens are the builders- preparing uterus for a baby)

which phase of the endometrial cycle describes marked swelling and growth due to **progesterone**

the secretory phase

what is progesterone known as

“the maintainer”

what are the two possible outcomes of the endometrial cycle

Menses or preganancy

what days does the proliferative phase take place

days 7-14

when does estrogen peak

just before ovulation

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(proliferative phase)

what does cervical mucus look like during ovulaiton

Cervical mucus at ovulation is clear, thin, watery, and alkaline; it is more favorable to sperm and has increased elasticity on microscopic exams.

what days of the endometrial cycle does the secretory phase take place

days 15-26

what happens to estrogen and progesterone during the secretory phase

Estrogen **drops sharply**, and **progesterone dominates.**

what changes do you see in the uterus during the secretory phase

* Vascularity of the entire uterus increases.

Tissue **glycogen increases**, and the uterus is made ready for implantation.

what days of the endometrial cycle does the menstrual phase begin

days 27-28

what happens to estrogen and progesterone during the menstrual phase

Both estrogen and progesterone **levels drop.**

what changes do you see during the menstrual phase

* Spiral arteries undergo vasoconstriction.
* Endometrium becomes pale; blood vessels rupture → Blood escapes into uterine stromal cells 
* gets ready to be shed.

description of the corpus luteum

yellow body that develops within a ruptured ovarian follicle

which structure produces progesterone

**Corpus luteum**

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(during the second half of the menstrual cycle )

what is the purpose for the Corpus luteum producing progesterone

produces progesterone to maintain thick lining of the endometrium if pregnancy occurs

what happens to the corpus luteum if no implantation occurs

it degenerates

definition of mitosis

production of diploid body or somatic cell division in which a single cell divides with each new cell comprising of the same number of chromosomes, 46. ( skin, blood)

definition of meiosis

process by which germ cells divide and decrease their chromosomal number by one half, producing gametes (eggs and sperm). Each has 23 chromosomes 22 + one sex cell.

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**Two gametes, ova (egg) and spermatozoon unite resulting in 46 chromosomes or 23 pairs**

definition of oogenesis

*  process of egg or ovum formation that begins during fetal life in females.
* At birth ovaries contain \~2 million oocytes; at puberty \~300, 000

definition of spermatogenesis

process of maturation in males in which spermatocytes become spermatozoa

how long are ova considered fertile after ovulation

 12 to 24 hours

how long can sperm survive in the female reproductive tract

48-72 hours

what are the two layers that surround the ovum’s cell membrane

zona pellucida and corona radiata

description of the **zona pellucida**

**this is the layer closest to the cell membrane**

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 It is a clear, noncellular layer whose thickness influences the fertilization rate.

description of the corona radiata

Surrounds the zona pellucida,

a ring of elongated cells

because they radiate from the ovum like the gaseous corona around the ovum

what holds the corona radiata cells together

* Hyaluronic acid →The ovum has no power of movement of its own.

which hormone aids in the movement of the ovum during ovulation

Estrogen

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* During ovulation, high estrogen levels increase peristalsis within the fallopian tubes, which helps move the ovum through the tube toward the uterus.
*  The high estrogen levels also cause a thinning of the cervical mucus, easing passage of the sperm through the cervix, into the uterus, and up the fallopian tube.

where does the process of fertilization occur

The process of fertilization usually takes place in

what two process must sperm undergo for fertilization to occur

capacitation and the acrosomal reaction. 

what is capacitation

* the removal of the plasma membrane and glycoprotein coat overlying the spermatozoa’s acrosomal area and the loss of seminal plasma proteins. 
* If the glycoprotein coat is not removed, no fertilization

where does **Capacitation** occur

occurs in the female reproductive tract (aided by uterine enzymes) and takes about 7 hours.

Sperm that undergo capacitation take on three characteristics what are they

1\. the ability to undergo the acrosomal reaction,

2\. the ability to bind to the zona pellucida,

3\. the acquisition of hypermotility.

describe the **acrosomal reaction**

* The **acrosome caps of the sperm surrounding the ovum release their enzymes** (hyaluronidase, a protease called acrosin, and trypsin-like substances) → thus break down the hyaluronic acid that holds the elongated cells of corona radiata (the outer layer of the ovum) together
*  About a thousand acrosomes must rupture to clear enough hyaluronic acid for even a single sperm to penetrate the ovum successfully.

when does the **acrosomal reaction occur**

after capacitiation

what is the classification (days) of the preembryonic stage

1st 14 days: starting on the day the ovum is fertilized (conception)

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when does cellular multiplication occur

begins as the zygote moves through the fallopian tube toward the cavity of the uterus → takes 3 days or more

once cellular multiplication occurs what period does the zygote enter

zygote enters a period of rapid mitotic divisions called **cleavage**

what happens during the cleavage period

during this phase it divides into two cells, four cells, eight cells, and so on called **blastomeres**