Biology 101 Final | Professor Duong

What can happen within the first week of pregnancy to the mother?

The vomit center sends signals to regurgitate to prevent potential toxins to the developing embryo.

ectoderm

The outermost layer of cells in the developing embryo, responsible for forming structures such as the skin and nervous system.

What is the first week of pregnancy called?

The critical period

Fertilization

sperm meets the egg

Zygote

fertilized egg (single celled)

Embryo

Early stage of pregnancy, has no distinguishable features

fetus

later stages of development

Bilateral symmetry

symmetry in the left and right side of the body

how can we test for hCG presence?

at home pregnancy test via urine and blood work at a doctors office

primitive streak

the line in the embryo made during development which determines the left and right side of the body that indicates the embryo is preparing for tissue development (week 2&3)

fertilization

when the sperm meets the egg and combines to become a zygote (week 1)

what is a zygote

a fertilized egg (single celled)

Fetus

later stages of development

Cleavage

A period of rapid cell division at 1-4 days of conception

Necessary to develop later organs (week 1)

Progesterone

controls the thickness of the endometrium

Higher progesterone = thicker endom.

Implantation

Embryo attatches to the endometrium where it receives its nutrients and oxygen via the blood rich nature of it

hCG, what secretes it?

Human Chorionic Gonadotropin - produced by the embryo

the pregnancy hormone

detectable via urine (at home pregnancy test)

and via blood test (doctor's office)

Blastocyst

The name of the embryo after 5 days

Generates cells that can turn into any type of tissue

Research being done to create stem cells

develops a fluid sack to protect the inner contents

What is the purpose of hCG

alert the mom that she is pregnant

keep progesterone levels high so that the endometrium does not shed and allows for growth of the embryo

Scientists often stop research on embryo during what stage of development

Primitive streak formation

Extra Embryonic Structures

Chorion, Amnion, Amniotic fluid (Week 2&3)

Chorion

outer membrane of the embryo; forms the placenta which attatches to uterine wall anchoring the fetus and nourishes the fetus through the umbilical cord

Amnion

The inner membrane that produces and stores amniotic fluid

Amniotic fluid

liquid which surrounds the fetus during pregnancy and protects the fetus acting as a shock absorber

can turn yellow after the fetus develops and produces urine

The fluid contains nutrients, hormones, and antibodies

Umbilical Cord

Tissue which connects the placenta to the fetus; carries oxygen and nutrients to the fetus while removing carbon dioxide and waste products

Gastrulation

formation of the three germ layers: Endoderm, Mesoderm, Ectoderm. (Week 2&3)

Endoderm

Forms the digestive system and lungs

Mesoderm

ALL MUSCLES: cardiac, skeletal, smooth (uterus, bladder, digestive system). cartilage and bone

Organogenesis

All the organs begin to form (week 4)

When do heart beats begin?

week 4

When do limb buds appear?

week 4

SRY Gene Activation

SRY - Sex-determining Region on Y Chromosome

is present on the male's Y chromosome and if active will develop a male repro.; if it is not then will develop female repro. but will be infertile

if Y chromosome is not present then the embryo will develop a female reproductive system

(Weeks 5&6)

Wolfian ducts turn into...

vas deferens/ vasa deferentia

Mullerian ducts develop into...

fallopian tubes

Males carry which chromosomes

X & Y

Females carry which chromosomes?

X only

Ossification

existing tissue turns into bone tissue

(weeks 5&6)

Apoptosis of limb buds

process where the fingers and toes undergoes cell death to result in the formation of individual fingers and toes

(weeks 7&8)

syndactyly

webbed fingers or toes

Neurons generate action

action potential, electrical signals which allow contraction of muscle

(Weeks 7&8)

testes

produce sperm cells

epididymis

site of sperm development and activity

vasa deferentia

tubes lined with smooth muscle that move the sperm out of the testes during ejaculation

Seminal Vesicle

this adds fructose and prostaglandins to semen

Fructose serves as energy for sperm to travel

Prostaglandins induce contractions within the female uterus to propel sperm up into the fallopian tubes

Prostate gland

adds alkaline fluid to semen to protect sperm cells from the acidic environment of the vagina/reproductive tract

Bulbourethral gland

secretes mucus to lubricate the urethra before ejaculation, cleans the urethra of urine

Penis

external reproductive organ of a male to deposit semen to the female vagina

Scrotum

a sac of skin and muscle that holds the testes externally for cooler climate for survival

Bladder

Stores urine

Ejaculatory Duct

vas deferens and seminal vesicle meet

combines sperm, alkaline fluid, and other fluids from seminal vesicle before semen is ejaculated

Pathway of sperm

testes→epididymis→vas deferens→ejaculatory duct→urethra→penis

Semen contents

95% seminal fluid, 5% sperm

Vasectomy

permanent method of male birth control, cuts off vas deferens to block the release of sperm cells during ejaculation

Ovaries

organs that produce and store eggs, two ovaries which alternate in releasing a single egg (oocytes) once a month for one chance at fertilization

Fllicle

layer consisting of small cells which nourish and protect a single egg

corpus luteum

structure remaining after egg leaves follicle during ovulation

Fimbriae

finger like ends of the fallopian tube which help capture the egg into the fallopian tube during ovulation

Fallopian tube (oviduct)

the structure that the egg is released into during ovulation

site of fertilization and tubal ligation

Endometrium

Blood rich tissue that lines the inside of the uterus

thins and thickens based on pregnancy status

stays thick when pregnant

sheds if not pregnant

gives nourishment to the embryo

Cervix

neck of the uterus which dilates during pregnancy

Uterus

also known as the womb, site of pregnancy

Vagina

site of sperm deposit, known as the birth canal

pathway of the egg through the female repro.

Ovary --> Fallopian tube (where egg can be fertilized) --> Endometrium (where fertilized egg implants into the uterus)

Tubal ligation

permanent form of female birth control

requires cutting and tying off of the fallopian tube

How long does the egg last after ovulation

12-24 hours before it decomposes

Sperm lifespan

2-6 days

Breach position

when baby's head is in opposition of the birth canal which causes difficulty in delivering

C-section

incision made in the bikini line to take the baby out

What is the last to develop in pregnancy?

Respiratory and digestive system

Estrogen is important in...

egg development

Progesterone is important in...

egg release

thickening the endometrial tissue

pH of Vaginal tract

4.3 until ejaculation --> 7

Describe the main purpose of the ovarian cycle.

Preparing the body for potential pregnancy by releasing the egg from the follicle so that it can be fertilized

Main purpose of the menstrual cycle (uterine cycle)?

the endometrium is shed in preparation for pregnancy when the female is not pregnant

What happens to estrogen and progesterone levels in the blood during week 1 of the ovarian and menstrual cycles?

they drop and menstruation begins

What happens to the follicle in week 2 of the ovarian and menstrual cycle?

they reach maturity

what happens to estrogen in week 2 of the ovarian and menstrual cycle?

it peaks

What is triggered by a peak in estrogen (week 3 of ovarian and menstrual cycle)

ovulation

What happens to progesterone in week 3 of the ovarian and menstrual cycle?

it peaks

what event is triggered by a peak in progesterone? (week 4)

thickening of the endometrium

What is an empty follicle called? (Week 4)

Corpus Luteum

What are the uses of the female Birth Control pill or "the pill"?

- regulate menstrual cycles

- reduce symptoms of medical conditions (polycystic ovary syndrome, endometriosis, uterine fibroids, and perimenopause)

- reduce heavy periods

- missing/skipping periods

- prevent unplaned pregnancy

Antibiotics can...

decrease effectiveness of birth control

Active pills contain..

estrogen and progesterone

inactive pills contain...

Iron (Fe), sugar, or empty/placebo

How to increase efficacy of "the pill"?

- take same time daily

- iron and sugar pills used to regulate routine usage

how do BC pills affect estrogen and progesterone?

it keeps them stable

What is the result of preventing a peak in estrogen?

ovulation is prevented.

What is the result of preventing a peak in progesterone?

lighter period/fewer days since the endometrium never thickens

PCOS

- cysts in ovaries

- Causes potential infertility

Endometriosis

- endometrial tissue found in different areas of the reproductive system which cause complications

Uterine Fibroids

- Tumors that grow in the uterus

- Non cancerous

- Medication (BC) to help reduce growth

Menopause

When estrogen/progesterone levels decline to the point of almost non-existent

HUMAN REPRODUCTION AND DEVELOPMENT: Step 1

- Ovulation

• week 1

HUMAN REPRODUCTION AND DEVELOPMENT: Step 2

- Fertilization; zygote enters Fallopian tube

• week 1

HUMAN REPRODUCTION AND DEVELOPMENT: Step 3

- Cleavage occurs in the Fallopian tube

• week 1

HUMAN REPRODUCTION AND DEVELOPMENT: Step 4

- Primitive streak formation

• week 2&3

HUMAN REPRODUCTION AND DEVELOPMENT: Step 5

- Development of extraembryonic structures

• week 2&3

HUMAN REPRODUCTION AND DEVELOPMENT: Step 6

- Gastrulation

• week 2&3

HUMAN REPRODUCTION AND DEVELOPMENT: Step 7

- Organogenesis occurs

• week 4