Reproduction and development - Second Copy Flashcards
What are Primary sex characteristics?
Organs present at birth (Testes, ovaries, penis, vagina)
What are secondary sex characteristics?
Developmental - prevalent after/during puberty (Facial hair, breasts, pubic hair)
What are ovaries?
Produce egg (Ovum), release estrogen and progesterone
What are the fallopian tubes?
Carries egg from ovary to uterus
What is the uterus?
The muscular organ where embryo develops
What is the cervix?
Tightly closed bottom of uterus, dilates during birth
What is the Vagina?
Birth canal, passage for sperm
What is the corpus Lutem?
- Temporary endocrine organ
- Old follicle after egg is released
- Broken down every month unless fertilization occurs
- Release estrogen and progesterone
What is the purpose of estrogen?
Thickens endometrium
What is the purpose of progesteron?
Maintains endometrium
What are the testes?
Produce sperm and testosterone
What are the seminiferous tubules? Where are they located?
Inside testes - Sperm production with Sertoli cells [FSH]
What are interstitial cells? Where are they located?
Inside testes - Produce testosteroen
What is the Epididymis?
Coiled tubes, store mature sperm
What is the vas deferens
Tube that carries sperm
What is the cawper gland?
Adds mucus to sperm, slightly basic
What is the seminal vesicle?
Adds sugar to semen (Energy for sperm)
What is the prostate gland?
Adds fluid to nourish and protect sperm (basic). Aids in release of sperm
What is the ejaculatory gland?
Opens to urethra, controls ejaculation
What is the urethra?
Tube that carries sperm and urine
What is the penis?
hehe (deposit sperm into vagina)
What are Sertoli cells?
Cells in seminiferous tubule that aid in sperm production
What is a germinal cell?
A cell that eventually becomes sperm
Where is the seminiferous tubule located?
In the testes
How many chromosomes do humans have?
46 (23 pairs)
What is the specific chromosome pair that determines sex?
23rd
What chromosomes do all humans have?
X
What chromosome do only men have?
Y
What does the Y chromosome dictate?
Stimulate production of testes
During development what do the testes secrete?
Secretes testosterone which leads to the development of male sex characteristics 6-7 weeks after fertilization.
What does the hypothalamus release to stimulate LH and FSH release from ant. Pit. Gland
GnRH
What does the pituitary gland secrete in response to GnRH?
LH and FSH
What is the role of LH?
Acts on interstitial cells to produce testosterone
What does FSH act on/role?
Sertoli cells - produce sperm (with the aid of testosterone)
What is the production of testosterone result in?
Negative feedback on hypothalamus
What does FSH do? [Females]
From pit. gland stimulates the growth of eggs. Signals ovaries to make estrogen
What is the role of FH? [Females]
Stimulates ovulation two weeks after menstruation. Stimulates corpus Luteum to make progesterone
What is the role of estrogen?
From ovaries, responsible for the development and regulation of the female reproductive system. Growth of endometrium
What is the role of progesteron?
From ovaries, prepares endometrium (Maintains and increases blood vessels)
What occurs on days 4-13 of the menstrual cycle?
Follicular phase - Blood levels of estrogen rise, growth follicle, medium levels of FSH and LH, low levels of progesterone, increase in endometrium thickness
What happens on day 14 of the menstrual cycle?
Ovulation - peak in LH levels, eggs released from ovaries, progesterone levels increase, estrogen lowers
What happens on days 15-28 of the menstrual cycle?
Corpus Luteum increases progesterone levels, and estrogen slowly lowers until 28, when menstruation occurs
What is menstration?
The shedding of the endometrium (if no implantation occurs)
What is morphogenesis?
Biological processes that causes a cell, tissue, or organism to develop it’s shape
What can pregnancy be split into?
Three trimesters or 2 halves
How long is pregnancy?
9 months, 40 weeks
What occurs during the first trimester?
Fertilization
Cleavage
Implantation
Gastrulation
Neurolation
Development of organs
What is clevage?
To split
What is nuerolation?
Formation of CNS
When does an embryo become a fetus?
8 weeks
What occurs during the second trimester?
Skin and hair grow
Fetal movement can be felt
Arms and Legs reach proportion
Eyes blink
Heartbeat can be heard (already developed in first trimester)
What occurs during the third trimester?
Increase in size, development of lungs, and fingernails, fetus can survive if born at this stage
What is the first half of pregnancy?
Embryonic development - Cells and tissues start to form, Structures to nourish embryo form
What is the second half of pregnancy?
Fetal development - Body growth, organ function,and system formation
When does fertilization occur? Where?
12 hours after ovulation, in the fallopian tubes
What is special about eggs and sperm to allow fertilization?
Both are gametes, meaniing the have half the DNA (23 chromosones)
When an sperm fertilizes a sperm what does it produce?
A zygote
Why is there only one sperm for one egg?
Depolarization of egg membrane prevents multiple sperm from entering egg
What is an acrosome reaction?
The acrosome reaction is a process where the acrosome, a cap-like structure on the sperm head, releases digestive enzymes to penetrate the egg’s outer layers.
What is a cortical reaction?
The cortical reaction is an egg’s response to sperm entry, where enzymes from cortical granules harden the zona pellucida (eggs membrane), blocking additional sperm and preventing polyspermy.
What is polyspermy?
Polyspermy is the fertilization of an egg by more than one sperm. This usually results in an abnormal number of chromosomes, leading to developmental issues that typically prevent the embryo from surviving.
What happens to the zygote?
Zygote division (clevage) - stays same size however
What does a zygotedevelop into?
Morula (16-32 cells)
What does the Morula do?
Travles to the unterus (3-5 days)
What does the Morula develop into?
The blastocyte
What is the structure of a blastocyte?
A hollow ball with an inner cell mass
What does the inner cell mass develop into?
Embroblast and then Embryo
What is the cavity in a blastocyte called?
Blastocoele
What is the outer layer of a blastocyte called?
Thropoblast
What does the thropoblast develop into?
Chorion and then placenta
What does the chorion deveolp into?
Placenta
What does the embroblast develop into?
Embryo
What is the role of the placenta?
Site of echange for oxygen and nutrients between mom and baby
What does the blastocyte do after developing?
Implants into endometrium
How does the trophoplast help implantation?
Releases enzymes to create path through endometrium
What does the trophoblast secrete?
hCG (Human Chorionic Gonadtropin)
What is the purpose of hCG
Maintains the endometrium by preventing breakdown of Corpus Luteum from breaking down (Continues to produce progesterone and estrogen)
At what times during pregnancy is hCG highest?
First 2 months falls off after month 4
What is responsible for hCG reduction by month 4?
After first trimester placenta produces enough progesterone and estrogen
What is grastulation?
When the single layer blastocyte develops into a three layered structure known as the gastrula
When does gastrulation occur?
Happens by week 2 after implantation
What are the three germ layers that are developed in gastrulation?
Ectoderm
Endoderm
Mesoderm
What does the ectoderm form into?
Skin and CNS
What does the endoderm develop into?
Respritory tract, digestive tract, endocrine organs
What does the mesoderm develop into?
Muscles, skeleton, blood vessels, reproductive systems
What does the space between the germ layers and trophoblast develop into?
Amnotic sac
What must happen to the Inner cell mass for gastrulation?
Mast flatten
What occurs after gastrulation?
Neurolation
What is neurolation?
Neurulation is the early developmental process in vertebrates where the neural tube, which eventually forms the brain and spinal cord, is created.
What are the steps of neurolation?
- The ectoderm thickens to form the neural plate
- The edges of the neural plate begin to elevate, forming neural folds, while the center forms a depression called the neural groove.
3.The neural folds continue to rise and move toward each other, while the neural groove deepens in the middle. - The neural folds meet at the midline and fuse, forming the neural tube..
- The neural tube fully closes, creating a hollow structure that will become the brain and spinal cord.
What occurs during weeks 3-8?
Membranes external to embryo develop, called extra-embryonic structures
What are the extra-embryonic structures?
Chorion - Becomes placenta
Allantois - Becomes umbillical chord
Yolk Sac - Makes red blood cells until bone marrow is developed
Amniotic sac - Provides protection
What does the trophoblast turn into?
Chorion
What is the purpose of chorionic villi?
Increase contact area with maternal blood
Carry blood to umbillical chord
After how long is the yolk sac around?
After 8 weeks the yolk sac shrinks
What is the positive feedback during childbirth?
- Post Pit. Releases oxytocin
- Uterine contracts
3a. Babies head pushes on cervix
3b. Prostoglandins is released (causes contractions) - Stretch recpetors send nerve impulse to post pit to release more oxytocin
Where is there a nerve impulse during reproduction and developemt?
During birth - Stretch receptors pick up babies head pushing against cervix resulting in a nerve impulse to be sent to the Post Pit.
What are the three stages of childbirth?
- Dialation (cervix, 10cm)
- Expulsion stage
- Placental Stage
What is a tetratogen?
Cause abnormal development
When is a tertogen most dangerous?
First 3 months - Greatest effect becuase cells are still dividing (greater % of damage)
Why do teratogens have no impact the first 2 weeks after conception?
No connection between mom and kid
Why does what the mother ingest affect the embryo/fetus?
The reason that what the mother ingests has an effect on the embryo/fetus is due to the transfer of nutrients through the amniotic fluid to the fetus.
What is FASD?
Fetal alcohol syndrome is the result of exposure to alcohol by a fetus during pregnancy. Common Physical, learning/thinking issues, and behavioural side effects of FASD include;
Facial features; small eyes, thin upper lip, flat nose bridge
Trouble with memory, learning new things, focusing, and thinking
Challenges in school with attendance, learning, behaviour, and interacting with others
What is IVF?
IVF is a treatment for infertility, its a series of procedures where mature eggs are fertilized by sperm in a lab and then the fertilized eggs are placed in a uterus
What are fertility drugs?
Fertility drugs are medications designed to help individuals or couples conceive by stimulating ovulation or enhancing reproductive functions
How do fertility drugs work?
They help promote the development and release of eggs from the ovaries, increasing the chances of conception. These medications can regulate menstrual cycles and address underlying hormonal imbalances.
What is artificial insemination
The medical procedure of injecting semen into the vagina or uterus - this is useful as it reduces the trip size and any obstacles obstructing semen
What are condoms?
Condoms work by creating a physical barrier between sperm and the vagina
What is the birth control pill?
Birth control pills are a form of medication that affect your hormones in order to prevent pregnancy
How do IUD’s work?
An IUD (intrauterine device) is a small, T-shaped contraceptive device inserted into the uterus to prevent pregnancy - creates an environment in the uterus that is inhospitable to sperm, reducing the chances of fertilization.
What is a diaphragm?
A diaphragm is a barrier method of contraception that is a dome-shaped cup made of silicone or rubber. It is designed to fit snugly over the cervix, preventing sperm from entering the uterus.
What is plan B
Levonorgestrel is a synthetic progestin used primarily as an emergency contraceptive. It prevents pregnancy mainly by inhibiting ovulation, which means it stops the ovaries from releasing an egg.
