Cleavage

Growth

Morphogenesis

Differentiation

First series of mitotic divisions in which overall original size of the zygote doesnt change, but the number of cells in the zygote increases.

Each cell receives a full complement of chromosomes and genes

refers to the shaping of the embryo and its first evident when certain cells are seen to move, or migrate, in relation to other cells.

By these movements, the embryo begins to assume various shapes.

when cells take on a specific structure and function, differentiation occurs.

The first system to become visibly differentiated is the nervous system.

Pre-embryonic Development

Embryonic Development

Fetal Development

* total gastration time: 3 weeks after fertilization

Not part of the embryo and fetus, instead are outside the embryo

- chorion

- yolk sac

- allantois

- amnion

the outermost embryonic membrane, that surrounds the embryo and other membranes.

Develops into the fetal half of the placenta.

- The organ that provides the embryo/fetus with nourishment and oxygen and takes away its waste

- only present during pregnancy

- fully functional at the end of the embryonic period

composed of 2 portions

- fetal portion made of chorionic tissue

- maternal portion made of uterine tissue

weeks 0-12 0: ovulation and fertilization

0-1: preembryonic development

1-8: embryonic stage

8-12: fetal stage

- formed about 4 days after fertilization

- compact ball of embryonic cells

- Formed around 5 days after fertilization

2 distinct parts:

- inner cell mass

- trophoblast

- occurs when cells in the morula split

- each half contains the exact same genetic info

- implantation someplace other than the uterus

- almost never go to term

- may become a life-threatening situation for the mother

- can be treated surgically or with medication

stage of development that begins with the second week and lasts until the end of the second month of development.

- after the embryo's journey down the fallopian tube, it will implant in the uterus, it has to first "hatch" out of the zona pellucida

- once implantation happens the pregnancy is clinically recognized

- 2nd week

- hormone secreted by trophoblast starting at the time of implantation

- helps maintain the corpus luteum

- signals the corpus luteum to secrete even high amounts of progesterone

- ovulation and menstruation do not occur

- is DETECTED BY HOME PREGNANCY TESTS

- 2nd week

- inner cell mass detaches from the trophoblast and flattens out into the embryonic disk

- embryo is transformed from a ball of cells into multiple layers of tissue

- cell migration forms 3 primary germ layers

ectoderm

mesoderm

endoderm

- third week

- tissue thickens on the backside of the embryo

- a groove forms when cells from the surface of the embryo move inward

- the folds fuse in the center and form the neural tube (develops into the brain and spinal cord)

- 3rd week

- begins beating around day 22

- beats twice as fast as mother's

- Formation of the nervous system

- Formation of the heart

- 4th week

- hands develop sooner than feet

- by the end of the embryonic period, the beginnings of fingers and toes can be seen

- limb buds (hands and feet) appear

- developing embryo is surrounded by extraembryonic membranes

- formed from blood vessels of the allantois

- connects the embryo to the placenta

- nutrients and oxygen-rich blood flow from the mom to the embryo

- carbon dioxide and other waste flow from the embryo back to the mother

- round trip from mom to embryo and back takes 30 seconds

- the mother's arteries bring oxygen and nutrient rich blood to the embryo

- her veins carry away blood containing carbon dioxide and other wastes

- these substances cross the placental membrane

- first synthesized by the trophoblasts before implantation occurs

- after implantation, the chorion takes over hCG production

- once fully formed, the placenta synthesizes hCG, as well as progesterone and estrogen

The spontaneous loss of a pregnancy before the fetus can survive outside the uterus.

- rate is highest in embryonic stage

- nearly 1 in 5 pregnancies end in miscarriage in the first 3 months

- genetic abnormalties are the most common cause

- embryo looks more human-like (7-8)

- all organ systems are established

- size at the end of this stage

(weight of a tablet of aspirin)

- Fetal Bones begin to harden

- Fontanels allow the skull to be flexible

- Sexual differentiation underway

(gonads differentiate into testes or ovaries)

- Fingernails, nipples, eyelashes, eyebrows, hair on head

- size at the end of this stage

(six inches long about 6 oz)

- fetus has been very active, but the movements have been too small for the mother to notice

- she may begin to feel fetal movements

around the 5th or 6th month

- kicks, pokes, hiccups

- white creamy substance covering the fetus

- protects the delicate fetal skin from the

amniotic fluid

- fine, downy hair that covers the fetus

- mostly lost before birth

- its purpose is not entirely clear

..starting at 26 weeks after fertilization

(third trimester)

- fetal movements can be felt by mother

- fetus covered in vernix and lanugo

- babies as young as 7 months

can survive outside the womb

- 12 inches 3 lbs

- fetus grows rapidly and accumulates fat

- lanugo and vernix mostly disappear before birt

- 95% of all fetuses are in a head-down position

- babies are considered full term at

35 weeks after fertilization

- blood volume increases by 40%

- followed by a large increase in the number of red blood cells

- lung capacity increases by 40%

- Growing uterus affects many areas of the body

- increases in size from 60-80 grams to 900-1200 grams

- compresses the bladder and may cause stress incontinence

- as the uterus grows, it pushes the abdominal cavity and widens the chest

- contains 14-20 lobules that contain blind sacs called alveoli

- mammary ducts lead from the lobules to the nipple

- during pregnancy, the ducts and alveoli increase

in number and size

- Sometimes strong uterine contractions that may be mistaken for true labor.

- true labor is marked by regular contractions that last 40 seconds or longer

- the cervix starts to open

- this triggers uterine contractions and the

release of oxytocin from the brain

- oxytocin further stimulates the uterus to contract

- contractions push the fetus downward

stretching the cervix more

- this positive feedback cycle repeats until the baby is born

The process of birth

- occurs in three stages

- may be preceded by a bloody show

- loss of mucous plug from the cervical canal

- prevented sperm and bacteria from

entering the uterus during pregnancy

- does not signal that labor is imminent

- Dilation

- Effacement

- Amniotic membrane usually ruptures

(water breaking)

- Over when the cervix is fully dilated

- Refers to the opening of the cervix

- Fully dilated = 10 cm (4 inches)

- Refers to the thinning of the cervix

- Cervix pulls upward towards the baby's head

 - Contractions

- Pushing Desire as baby's head

moves into the vagina

- the baby is born

- Once the baby is breathing

normally, cut umbilical cord

Afterbirth

- contractions shrink the uterus and dislodge the placenta

- Once the placenta and its membrane are out, birth is complete

- Alternative to vaginal delivery

- surgical incision in the front of

the abdomen and uterus

- performed when it is felt that it would be safer for

mom and baby than vaginal birth

Lactation requires the hormone prolactin

- Secreted after Birth

- Milk production takes a few days to start

Breasts produce colostrum before milk

- thin, yellow milky fluid

- contains many antibodies If baby is not

breast fed, milk production will stop

- all our genetic information is encoded in our dna

- are genes are short stretches of dna

- our dna is found in the nucleus of almost

every kind of cell in our bodies

- each long dna molecule gets packaged up into a chromosome

- various human disorders result from abnormal chromosome number and structure,

22 nonsex chromosomes

- nondisjunction

- down syndrome (trisomy 21)

- cri du chat syndrome

sex chromosomes

Sex chromosomal syndromes

xx or xy differ between the sexes

- abnormal sex chromosome number

- turner syndrome

- klinefeltner syndrome

- poly x females

- jacobs syndrome

Errors in chromosome separation

during meiosis I or II

- monosomy: only 1 copy of a chromosome

- trisomy: 3 copies of a chromosome (-1 or +1)

- Cause of many human disorders

- autosomal syndromes

- sex chromosomal syndromes

also called trisomy 21 because the individual usually has three copies of chromosome 21.

In most cases, the egg had two copies of this chromosome instead of one.

- risk increases with moms age

- a chromosomal deletion is

responsible for this syndrome

- named cat's cry because their

cry sounds like a meow

- portion of chromosome 5 is missing (deleted)

(xo) Has only one sex chromosome, an x; the o signifies the absence of a second sex chromosome.

Turner females are short with a broad chest and folds of skin on the back of their neck

The sex organs are small and underdeveloped. Do not undergo puberty or menstrate, breasts do not develop.

male has two or more x chromosomes in addition to a y chromosome.

- testes and prostate gland are underdeveloped

and there is no facial hair

- some breast development may occur

- large hand and feet and long arms and legs

- slow to learn but not mentally retarted unless they inherit more than 2 x chromosomes

- inherit more than two x chromosomes and therefore they have extra barr bodies n the nucleus.

- females with three x chromosomes have no distinctive phenotype aside from a tendency to be tall and thin

- some have delayed motor and language development

- (males xxy)

- can only result from nondisjunction

during spermogenesis

- usually taller, suffer from persistent acne, and tend to have speech and reading problems

- all of our genetic information is encoded in our DNA

- our genes are short stretches of DNA

- our DNA is found in the nucleus of almost

every kind of cell in our bodies

- each long DNA molecule gets packaged up into a chromosome

- everyone inherits 1 copy of a chromosome from mom and 1 copy from dad

- each chromosome contains the same genes

gene on a particular chromosome is called an allele

- masks the expression of a recessive allele

- represented with uppercase letters

- dominant is not the same as common

- Masked by a recessive allele

- represented with lowercase letters

genes of an individual for a particular trait or traits; designated by letters

- 2 alleles together determine a genotype (1 from mom & dad)

- the combination of the alleles determines our genotype

3 possible combinations:

 AA (homozygous dominant) - aa (homozygous recessive)

Aa (heterozygous)

homozygous dominant genotype

homozygous recessive genotype

heterozygous genotype

Haploid sex cell; the egg or a sperm, which join in fertilization to form a zygote

- carry one allele of each gene

Refers to physical appearance

(brown eyes, detached earlobes, freckles, straight hair, long eyelashes)

shows all possible combinations of alleles from genotypes of parents (one trait crosses)

Often used to test for dominant and recessive genes in two separate characteristics.

many of our characteristics are

influenced by more than 1 gene

- several different patterns of inheritance

- polygenic inheritance

- multiple allelic traits

- incomplete dominance

- sex-linked traits

- each dominant allele contributes

pigment to people's skin

- The more dominant alleles they have,

the darker their skin is 

- polygenic inheritance

- skin color

- more than one gene contributes to the phenotype

there are 3 possible alleles for the gene that controls blood type: A, B, or O.. A and B are dominant over O

- If both A and B are present, they are both expressed

  genotype: AA or AO phenotype: Type A

genotype: BB or BO phenotype: Type B

Genotype: AB Phenotype: Type AB

Genotype: OO Phenotype: Type O

Inheritance pattern in which the offspring has an intermediate phenotype compared to those of its parents

 example: hair, straight curly or wavy

- there is no dominant hair type

- straight HH, wavy HH', Curly H'H'

example, flower color (white + red = pink)

- blood type

- several alleles of a single gene

Allele that occurs on the sex chromosomes but may not control a trait that has nothing to do with the sex characteristics of an individual

color blindness

(the allele for red-green color blindness

is on the x chromosome, recessive)

- found on autosomes

(expression is influenced by sex hormones)

Example: baldness

- women must have 2 alleles for baldness

- testosterone + 1 allele = baldness for men

- therefore, the allele for baldness is dominant in men

but recessive in women

deals with the expression of genes by studying the DNA sequences of chromosomes.

- double stranded molecule

- found exclusively in the nucleus

- backbone of DNA molecule is PHOSPHATE and SUGAR

- Nucleotides (bases:)

Adenine (A) Tymine (T) (a only pairs with t)

Cytosine(C) - Guanine (G) (c only pairs with g)

spiral staircase twist of a DNA molecule

Chromosome

- coiled up DNA double helix

- humans have 46

- each chromosome is 1 long strand of DNA Gene

- segment of DNA

- humans have somewhere between

20,000 and 25,000 genes

- Creates proteins

- DNA is the blueprint for all proteins

needed in the body

- When a gene is turned on, its corresponding protein is made (The gene is "expressed")

- workhorses of the body & large molecules

- long strings of AMINO ACIDS

(20 different kinds of amino acids arranged in a specific order)

- proteins differ by the order and number of amino acids

- found in every part of the body carry out many different types of jobs

- give structure and shape to cells and tissues

- enable organs to function

- control different processes in the body Enzymes are a type of protein

- speed up chemical reactions

- allow cells to grow and reproduce

- the middleman between DNA and proteins

- DNA stays in the nucleus, but proteins are made in the cytoplasm

- RNA acts as the go-between

- is a mobile messenger that can travel from the nucleus out to the cytoplasm

- SINGLE stranded molecule

- the sugar is different than DNA

- instead of T RNA has U

- RNA bases can pair up with DNA bases

- assembled in the nucleus

- instructions spelled on in DNA are

copied into messenger RNA

- RNA bases are complementary to DNA sequence

- sets of 3 DNA bases code for amino acids

- mRNA carries the information out of the nucleus

Process whereby a DNA strand serves as a template for the formation of mRNA

- mRNA carries information out of the nucleus..

organelles in the cytoplasm where proteins are made

- made up of 2 halves that 'chomp' down on mRNA

Ribosomes move along the mRNA and read the letters in groups of 3

translates mRNA into protein (interpreter)

2 main features:

- anticodon: 3 base pairs that match up with mRNA

- amino acid that corresponds to the 3 base pair code

Each type of amino acid has its own tRNA molecule

Three-base sequence in a transfer RNA molecule base that pairs with a complementary codon in mRNA

- converting the mRNA sequence into a protein

- the anticodon loop of the tRNA pairs with the 3-base codon found in the mRNA

- the amino acids brought in by the tRNAs gets linked together in the growing protein chain

Permanent change in the DNA sequence

- may have no effect

- may cause a significant change

2 Common types:

point mutations & frameshift mutations

Change in only one base in the

sequence of bases in a gene

- sickle cell anemia

- Result from the insertion or deletion of bases into the DNA sequence

- The change usually results in an entirely new sequence of codons

THE CAT ATE THE RAT (if we lose c..)

THE ATA TET HER AT

- Caused by a mutation in the DNA sequence

- can be classified according to different factors

- type of chromosome affected

- dominant or recessive disease allele

- Anyone who inherits at least 1 dominant allele will have the disease

- Neurofibromatosis & Huntington Disease

- Affected children have at least 1 affected parent

- heterozygotes have the disease

- 2 affected parents may have affected children

- 2 unaffected parents will never have an affected child

- males and females are affected with equal frequency

- Affected person must inherit 2 recessive alleles

 Cystic Fibrosis, Phenylketonuria, Tay-Sachs disease, Albinism

Unaffected parents can have an affected child 

heterozygotes have a normal phenotype

- affected parents will always have affected children

- males and females are affected with equal frequency

- Mutation on the x chromosome

 almost always recessive

- color blindness is a common example of an xlinked disease

- more males than females are affected when a recessive trait is x-linked

- recessive alleles on the x chromosome are always expressed in males

- an affected son can have unaffected parents - an affected daughter must have an affected father and a mother who is either a carrier or who is affected

- if a mother is affected, all her sons will be too

prospective parents my want to know the chances of their child having a particular genetic disorder

helps determine the genotype of prospective parents

- charts a family's history of a particular genetic trait

EXAMPLE 1: 2 unaffected parents, affected child disorder is recessive, parents are heterozygotes (carriers)

EXAMPLE 2: Both parents are affected, but child is unaffected. Autosomal Dominant. Parents are Aa but passed on little as..

Biochemical testing

- performed for diseases caused by a missing enzyme

- not as conclusive as DNA testing DNA Testing

- takes advantage of the fact that the specific mutation in the DNA sequence that causes many diseases is known

- Amniocentesis

- Chorionic villi sampling

- Mother's blood

- obtains fetal cells from the amniotic fluid

- sample of the fluid is taken with a long

needle passed through the abdomen

- typically not performed until after the 12th week

- risk of miscarriage increases .5%

- Retrieves fetal tissue from the placenta

- sucked out with a long tube inserted through

the vagina into the uterus

- can be performed as early as the 5th week

- risk of miscarriage increases by .8%

- fetal cells can be separated from a sample of the mom's blood

- performed anytime after the 9th week

- only 1 in 70,000 cells will be from the fetus

- no increase in risk of miscarriage

- Performed when a couple wants to use invitro

- Examining the DNA of an egg would mean that egg could not be fertilized, instead scientists look at the DNA in the polar body

- A cell can be removed from a 6-8 cell embryo without impacting development, only embryos without the disease alleles would be transferred

- separation error during meiosis I (non disjunction)

and/or separation error during meiosis II

- bacterial

- viral (virus)

- caused by other organisms

- Chlamydia

- Gonorrhea

- Syphilis

- bacteria

- leading STD in US

- mens symptoms are either absent or mild

- symptoms in women include discharge and symptoms of urinary tract infections

- Bacteria

- Men experience symptoms 3-5 days after infection

(pain during urination, milky disharge)

- women are asymptomatic until they experience extreme abdominal pain

- result in PID (pelvic inflammatory disease)

- Bacterial

3 STAGES

- Primary: hard chancre at site of infection

- Secondary: rash

- Third: infect may progress to the cardiovascular and nervous system each stage can be separated by latent periods

- Not capable of reproducing on their own,

need a host for this to happen

contain 2 basic parts:

- outer capsid

- inner core of DNA or RNA

- viruses may have a latency period (inactive)

- genital herpes, genital warts, hepatitis B, HIV-AIDS

- caused by virus

2 types:

- HSV 1 - cold sores and fever blisters

- HSV 2 - genital herpes

- crossover infections do occur

- the appearance of blisters on the genitals is

preceded by a tingling or itching feeling

- caused by HPV

- about 20 million people in us infected

- carriers may not have signs

- associated with several cancers including cervical

- can be removed through surgery, acid, laser burning, or freezer

- A DNA virus that infects the liver

- only half of infected people experience

flu-like symptoms

- prevented with the HBV vaccine

- Thrichomoniasis

- pubic lice

- Caused by the organisms

- Accounts for 25% of all cases of vaginitis

- Symptoms include discharge and itching

- If untreated, it can invade the urinary tract

- May affect cervical cells,

eventually causing cervical cancer

- Caused by organisms

- Infest the pubic hairs

- lay eggs on base of hair

- can be easily treated

Human Immunodeficiency Virus

- infects T lymphocytes

- type of white blood cell

(key component of the immune system)

- causes AiDS in infected people

- needs a host to reproduce and survive

- needs to stay in bodily fluids

A - Acquired - it's a condition you must 'get'

I - Immune - affects the body's immune system

D - Deficiency - the immune system not work properly

S - Syndrome - There is a wide variety of different diseases and infections that people with AIDS can experience

- HIV stores its genetic info on a single strand of RNA

- once inside a host cell the viral

RNA is copied into DNA

- the viral DNA inserts itself into a host chromosome - This DNA contains instructions to

make new virus particles

Reverse Transcriptase

- enables RNA to be transcribed into DNA (backwards)

Inegrase - Splices the viral DNA into a host chromosome Protease

- Chops up viral proteins into small enough pieces to fit inside a new virus particle

- What people with AIDS die oF

- has the opportunity to occur because the immune system is severely weakened

- pneumonia, tuberculosis, and cancer

- As HIV replicates in the host, it can become resistant to drugs

- doctors recommend that patients take a cocktail of different drugs

- combines drugs from 2 different classes to effectively suppress the virus

- termination of a pregnancy before the fetus is able to survive outside the womb

- different types of abortions: spontaneous (miscarriage) or induced

- occur before 20th week of pregnancy

- chromosomal abnormalities are found in over half of early miscarriages

- the woman's risk of miscarriage drops significantly after the 10th week

- most common

- requires woman to go to hospital or clinic

- uterine aspiration

- dilation and evacuation

- surgical abortion

- only performed in first 3 months

- woman is given local anesthesia

- cervix is dilated with a series of metal rods

- contents of the uterus are suctioned out with a tube connected to a vacuum

- Surgical Abortion

- Performed in 4th or 5th month

- given anesthesia

- Cervix is dilated as in uterine aspiration

- Uterine contents are suctioned out with a vacuum - Walls of the uterus are scraped with a long instrument called a curette

- abortion pill to medically induce an abortion was approved by FDA in 2000

- can be prescribed by a family physician or

obstetrician/gynecologist and taken at home

- typically needs to be used in the first 9 weeks of pregnancy

- 2 drugs are taken 2 or more days apart Mifepristone

- blocks the action of progesterone

- causes the endometrium to break down Misoprostol

- induces uterine contractions Abortion is usually complete within a week

- if either medication fails the woman will require a surgical abortion

Roe vs Wade - legalized abortion in the US

PlannedParenthood vs Casey - weakened legal protections provided by roe vs wade

Inability to have as many children as desired

- 15% of American couples are infertile

- failure to get pregnant after 1 year of regular, unprotected intercourse

- problems with male 40%

- problems with female 40%

- problem with both partners 20%

Issues with sperm

- quantity, too few sperm reduces fertility

- quality, abnormal morphology (shape) and mobility (swimming) reduce fertility

Permanent:

- undescended testicles, sex chromosome abnormalties, infections that block the reproductive tract, chemotherapy

Reversible decrease in fertility:

heating of the testicles, smoking, sedentary lifestyle, alcohol consumption

Reproductive tract abnormalities:

fallopian tubes can become blocked as a result of Pelvic Inflammatory disease, endometriosis causes some structural abnormalities that complicate conception

Problems with Ovulation:

Post pubertal women can stop cycling or cycle irregularly, weight loss, athletic training, stress, certain drugs, obesity

- Artificial Insemination

- In Vitro Fertilization (IVF)

- In vitro maturation (IVM)

- Intracytoplamsic sperm injection (ICSI)

- Surrogacy

- Woman is given drugs to stimulate development of multiple eggs

- Sperm are directly placed in woman's vagina or uterus by a physician

- Sperm can be from her partner or a donor

- Useful if the male partner has low sperm count

- in a petri dish

- woman takes drug to stimulate follicle development

- oocytes are collected from the follicles using a thin needle

- sperm and egg are mixed together in dish

- after 2-4 days embryos are transferred

back to the mother's uterus

- success rates decline with increasing age of mother

- Used when a man has severe infertility

- a single sperm is injected into the cytoplasm of an egg

- bypasses the need for sperm to swim

- just like IVF, embryos are transferred back to the uterus 2-4 days later

risk with egg donation

- painful swelling of the ovaries from fertility drugs

- blood clots and kidney failure

Used by couples who can not carry a pregnancy

- woman who have a malformed uterus or

are not in good general health

- gay couples who want children 2 types:

traditional: - surrogate's eggs are fertilized with the man's sperm using artificial insemination

Gestational: - couple's own eggs and sperm are used, embryos created via IVF

Vasa deferntia cut and tied

- no sperm is in the semen

- almost 100% effective

Uterine tubes are cut and tied

- no eggs in uterine tube

- almost 100% effective

pill is taken daily, anterior pituitary

does not release FSH and LH

- about 100% effective

Injections monthly, anterior pituitary does not release FSH and LH

- almost 100% effective

Used Monthly Anterior pituitary

does not release FSH and LH

- about 100% effective

Newest device contains progesterone

and lasts up to five years

- prevents implantation

- more than 90% effective

Sponge permeated with spermicide

is inserted in vagina

- kills sperm on contact

- about 90% effective

Latex cap inserted into vagina to

cover cervix before intercourse

- Blocks entrance of sperm to uterus

- with jelly, about 90% effective

Latex cap held by suction over cervix

- delivers spermicide near cervix

- almost 85% effective

Latex sheath fitted over erect penis

- traps sperm and prevents STDS

- about 85% effective

Polyurethane liner fitted inside vagina

- blocks entrance of sperm to uterus

and prevents STDS

- about 75% effective

Penis withdrawn before ejaculation

- prevents sperm from entering vagina

- about 75% effective

Spermicidal products inserted before intercourse

- kills a large number of sperm

- about 75% effective