Biology Unit 1 (Reproduction)

Cleavage

-Cell division without growth

-Composed of three stages

-Happens so fast the cell doesn’t have time to replicate cytoplasmic contents

Morula

When the zygote has 16 cells

Blastula

embryo of the stage of implantation

Trophoblast

Forms placenta and secretes HCG

Human Growth Hormone

secretes estrogen + progesterone to maintain endometrium + prevent ovulation

Gastrulation

The formation of 3 primary germ layers

Gastrula

The developing embryo

Primary Germ Layers

The first layers of the cells that form during embryonic development

Ectoderm

-Outer germ layer

-Forms skin, nervous system (brain + spinal cord), sense organs

-Ectodermal cells form the neural tube

Mesoderm

-Middle germ layer

-Forms muscles, bones, and cartilage, components of blood

-Mesodermal cells will form the notochord- the backbone

Endoderm

-Inner germ layer

-Lining of the respiratory system and digestive system

Differentiation

The process that allows specialization of cell function. All future tissues and organs systems of the body will develop from the cells of the germ layers

Neurulation

-Development of the brain and spinal cord

-At two weeks, neurulation begins

-The developing embryo becomes a neurula

Germ layer

A group of cells that are going to differentiate collectively

Extra-embryonic membranes

System of membranes external to the embryo,. used for protection, nutrition, respiration, and excretion

Allantois

Forms the umbilical cord

Amnion

Fluid-filled sac used for protection

Chorion

Forms the placenta

Yolk Sac

Site for the first blood cell production

Placenta

-Formed from the chorion, it attaches the fetus to the uterine wall

-Nutrients and oxygen diffuses from the mother’s circulatory system to the baby and waste products leave that baby’s circulation

Fraternal Twins

-Dizygotic Twins

-Two eggs, two sperm, two separate fertilizations

-Twins are not genetically identical

Identical Twins

-Monozygotic Twins

-One egg, one sperm, one fertilization

-The zygote splits

-Twins are genetically identical

Parturition

The process of giving birth

Dilation

-Birth contractions cause cervix to dilate

Expulsion

-The baby is born

-It pushes through the cervix to the birth canal

Placental

After the birth, the placenta and umbilical cord (afterbirth)

Partuition Feedback Control

-Positive Feedback Mechanism

-Oxytocin released by pituitary gland

-Causes uterine contractions

-Cervix dilates and uterus to secrete prostaglandins

-Continues until birth

Lactation

-Positive Feedback Mechanism

-Caused by prolactin

-The suckling reflex

Teratogens

-An agent that causes a structural abnormality of a fetus due to exposure

-Worse during the first trimester

Home Pregnancy Test

Checks for HCG hormone in urine

Maternal Blood Test

Used to measure hCG levels, test for gestational diabetes, and evaluate chromosomal abnormalities

Ultrasound

Uses sound waves to create an image of the fetus, provides information about physical abnormalities, and is non-invasive

Amniocentesis

-A needle is used to draw amniotic fluid from the uterus

-Done at 14 weeks

-Used to check for chromosome abnormalities

-Highly Invasive

Chorionic villus sampling (CVS)

-Cells are taken from the chorion to create a Karyotype

-Around 9 weeks of pregnancy

-Used to check for chromosome abnormalities

-Highly invasive

Karyotype

An individuals complete set of chromosomes

Cell-free DNA prenatal screening

-A blood test is done to look for DNA fragments in the placenta

-Non-invasive but a positive test result must be confirmed with an invasive method

Fetoscopy

A procedure where a small instrument (laparoscope) is inserted into the uterus in order to see the fetus and placenta

Sterile

Inability to have kids

Infertile

Difficulty conceiving (Tryiing for 1+ years)

Male Infertility

-Obstruction in ductus deferens

-Low sperm count

-High # of non-viable sperm

-Inability to achieve erection

Fermale infertility

-Blocked oviducts

-Failure to ovulate

-Endometriosis

-Damage eggs

Artificial Insemination

-Sperm are collected and concentrated before being place in uterus

-Usually male infertility (cryopreservation)

Invitro Fertilization

Follicles that are closed to ovulation are identified and placed in glassware with sperm

In Vitro Maturation

Immature follicles are taken out of ovaries and are treated in the lab to avoid risks of stimulating ovaries

Gamete Intrafallopian Transfer (GiFT)

Sperm and egg are brought together in oviduct

Intracytoplasmic Sperm Injection (ICSI)

1 sperm is injected into an egg

Surrogate Mother

May be used by a infertile couple or a high risk mom

Super Ovulation

-Hormone treatment to cause ovulation of multiple eggs

-Women who have irregular cycles

-Increases chance of multiple births

Surgical Sterilization

-Vasectomy, tubal ligation and hysterectomy

-0% chance of pregnancy

Hormonal Contraceptives

Form of Reducing Reproductive Potential using hormones

Physical/Chemical Barriers

Form of reducing reproduction that includes barriers

Natural Methods

Form of reducing reproduction that can include ovulation tracking

Centrioles

During cell reproduction they produce microtubules that will eventually pull the chromatids apart

Chromosome

Short and fat DNA

Chromatid

Duplicated DNAthat is joined to its sister chromatid at the centromere and is separated during cell division.

Chromatin

-Long and thin DNA

-Stable form of DNA

Carbohydrates

Sugars

Monomer: Saccharide

Lipids

Monomer- Glycerol + Fatty Acids

Proteins

Monomers-Amino Acids

Nucleic Acids

Monomers-Nucleotide

Deoxyribonucleic Acid

Made of individual units called Nucleotides

G1 Phase (Interphase)

In this phase the new (baby) cell undergoes rapid growth and development

Synthesis Phase

During this stage DNA replicates (semi conservative DNA replication)

Centromere

A protein that holds two chromatids together; found all DNA

G2 Phase

Preparation for Mitosis

The centrioles replicate and move to opposite poles of the cell

2 centrioles replicate themselves

Prophase

-the nuclear membrane disintegrates

-the chromatin condense to become chromosomes (shorten and thicken)

-the centrioles produce spindle fibres

-the nucleolus disappears

Metaphase

-the alignment phase

-during metaphase the chromosomes align at the center (equator0 of the cell

-the spindle fibres attach to the centromeres of each chromosome

Anaphase

-the seperation phase

-during this stage the spindle fibres pull the chromatids apart

-they retract towards the poles of the cell

Telophase

-the spindle fibres disintegrate

-the nuclear membrane reforms around each set of DNA

-the chromosomes elongate and become chromatin (stable form of DNA)

-the cell membrane begins to invaginate

-the nucleolus reappears

Cytokinesis

-this is the last stage of the cell cycle

-the cell invaginates at the center to form two new identical daughter cells

Homologous chromosomes

-these are the chromosomes that have the size, shape, and genetic content

-they differ only in their alleles

Seminal Vessicle

-produces sugar and prostaglandins

-the sugar provides energy for the sperm

Prostate Gland

produces an alkaline base that reduces the acidity of the vagina

Cowper’s Gland

-provides a prejaculatory fluid

-it lubricates and provides a medium for sperm to swim

Vagina

An entrance for the erect penis to deposit sperm during sexual intercourse and an exit for the fetus during childbirth

Cervix

An opening/exit to the uterus, a thick-walled muscular organ hat expands to six times it’s size to accommodate a fetus

Endometrium

The lining of the uterus that is richly supplied with blood vessels to provide nutrients to a developing fetus. The - is affected by the changing hormone levels of the menstrual cycle

Myometrium

The external part of the uterus. Contains the muscle.

Follicle

Each follicle will eventually produce an egg

Oviducts

transfer an ovum from the ovary to the uterus. The lining of each tube is ciliated to create a current that moves the ovum toward the uterus

Fimbriae

finger like projections in the openings of the oviducts which sweep over the ovaries. The fimbriae are ciliated to sweep an ovum into an oviduct for it’s trip to the uterus

Glanol

Secretes chemical substances for use in the body or for discharge out of the body

Hormone

Chemical signals that are sent to many parts of body through the bloodstream

Negative Feedback Mechanism

regulatory system in the body that works to return the body to it’s normal internal state

Positive Feedback Mechanism

regulatory system in body that DOES NOT return the body to it’s normal internal state

Stages of the Menstrual Cycle

1. Follicular Stage

2. Ovulation

3. Luteal Stage

4. Menstruation