Reproductive Flashcards
What is a zygote?
Zygote – Flashcard Format
✅ Definition:
• A zygote is the first cell of a new organism, formed when a sperm fertilizes an egg.
✅ Key Facts:
• Diploid cell (46 chromosomes) → 23 from sperm + 23 from egg.
• Undergoes rapid cell division (mitosis) to form an embryo.
• Occurs in the fallopian tube before implantation in the uterus.
✅ Why It Matters:
• It’s the starting point of human development.
• Abnormal zygote formation can lead to genetic disorders or failed implantation.
Describe the structure of the vagina
The vagina, a fibre muscular tube 7 to 9 cm long, which can stretch a great deal during the birth process
The vagina produces lubricating secretions, its home to millions of bacteria which help maintain vaginal health, lactobacilli produce lactic acid that helps maintain acid pH of less than 4.5
Low pH reduces the chance of invasion by external bacterial pathogens or fungi
Describe and explain the structure of the cervix
The cervix is the entrance to the uterus which extends to the vagina
It is 3 cm long and 2.5 in diameter
The opening of the cervix in the vagina is normally less than 1 cm wide but during child can expand to 10 cm and return to normal after delivery
During the menstrual cycle, the cervix is covered with a thick acid mucus to prevent bacteria from entering the uterus. However in the fertile states the mucus becomes thinner and plentiful will alkaline pH THOT to help the sperm through the cervix the uterus.
Explain the function structure of the uterus
The uterus the organ which the baby grows develops
The body and Fun have thick walls of smooth muscle
The body of the uterus is lined with endometrium which thickens and becomes more vascular each month in preparation for pregnancy. If pregnancy does not happen the thickened endometrium is lost during menstrual bleeding
If fertilisation does happen, the embryo and plant itself into the endometrium and it continues to grow and develop in the uterus after about 10 weeks is known as a fetus
Explain the structure and function of fallopian tubes
Fallopian tubes (oviducts) I found it either side of the uterus I know about 10 to 12 cm long with specialise ciliated epithelium
They are the site of fertilisation of the over (egg) by sperm
When over is released from the ovary, it is guided into the fallopian tubes by the wide ends of the tubes known as funnels of the OViduct or Fimbria
The ovaries are not physically attached to the fallopian tubes but are positioned near them to allow egg capture during ovulation by timbres which sweep them into the fallopian tubules
Explain the structure function of the ovaries
The ovaries, the primary sex organ, the source of mature eggs on the endocrine organ that produces steroid sex hormones, oestrogen, and progesterone (prepare endometrium for conception and maintain pregnancy if fertilisation occurs) these sex hormones aid in development of sex characteristics such as breast and female body shape
At birth, the ovaries contain 1 million follicles containing ovum no new eggs are developed after birth and 400 to 500 eggs will be ovulated during lifetime. These cells are called oocytes
In the ovaries immature eggs are found in follicles which mature each month when they are mature they’re about 1.5 cm it developed cells that secrete oestrogen and small amount of progesterone just before ovulation
A thick layer of material known as Zona pellucida forms around the oocyte due to follicle secretion and the mature follicle is called a Graafian follicle.
Describe the structure and function of the mammary glands
The mammary glands or breasts are modified sweat glands that are part of the skin system
Each gland consist of 15 to 20 lows which are separated from each other by connective tissue and fat each load contains a cost of alveolar glands which produce milk when a woman is lactating
The lactiferous ducks open outside via the nipple to release milk consisting of 88% water 7% lactose 4% fat one percent protein and various ions including calcium, sodium potassium phosphate and chloride and a wide range of growth factors along with antibodies to protect the baby from some diseases This is the ideal food for human babies.
Explain the step-by-step process of the menstrual cycle and the hormones involved
Step-by-Step Menstrual Cycle – Flashcard Format
✅ Overview:
• The menstrual cycle (~28 days) prepares the ovaries & uterus for pregnancy.
• Controlled by the hypothalamus, pituitary gland, ovaries, and uterus.
• Regulated by hormones: FSH, LH, estrogen, and progesterone.
- Follicular Phase (Days 1-14) – Egg Matures
🩸 Menstruation (Days 1-5):
• Old uterine lining sheds if no pregnancy.
• FSH (Follicle-Stimulating Hormone) from the pituitary gland stimulates ovarian follicles (each contains an oocyte).
🟢 Follicle Growth (Days 6-13):
• FSH makes follicles grow in the ovaries.
• One follicle becomes dominant Graafain follicle, producing estrogen.
• Estrogen thickens the uterine lining (endometrium) for implantation.
🚀 Ovulation (Day 14 – Egg Released):
• High estrogen triggers a surge of LH (Luteinizing Hormone) from the pituitary gland.
• LH causes the mature follicle to rupture, releasing a secondary oocyte from the ovary.
• The oocyte enters the fallopian tube, waiting for fertilization.
- Luteal Phase (Days 15-28) – Uterus Prepares for Pregnancy
💛 Corpus Luteum Formation (Days 15-21):
• The ruptured follicle becomes the corpus luteum in the ovary.
• The corpus luteum secretes progesterone & some estrogen.
• Progesterone maintains the uterine lining & prevents new follicles from developing.
⚠️ If No Pregnancy (Days 22-28):
• The corpus luteum breaks down → progesterone & estrogen drop.
• The uterine lining starts shedding, leading to menstruation (new cycle begins).
• Low hormones signal the pituitary to release FSH, starting a new cycle.
✅ If Pregnancy Occurs:
• Embryo releases hCG (human chorionic gonadotropin) → keeps the corpus luteum alive.
• Progesterone stays high, preventing menstruation.
Explain menopause and menarche
Menarche is the first period a girl has and is around 13 years of age but can arrange from 8 to 18. Usually it may take time for the mental cycle to settle into a regular pattern. The first few cycles do not produce mature over a normal menstrual cycle varies between 21 to 35 days.
Menopause takes place when the finite number of follicles in the ovaries are used up oestrogen and progesterone levels full menstrual periods become erratic and eventually stop usually between the ages of 45 to 55
Symptoms may be mild and the minor nuisance or they can suffer from palpitations night sweats hot flashes UTI loss of libido changes in mood long-term reduction in bone density increase risk of heart problems
Explain the function of the testes
Produce male sex hormone testosterone and sperm as well as the main sex organ
The test is developed in the abdomen wall in a fetus and descend into scrotum on the seventh month of fetal development. They are pad organs located outside the body cavity on the scrotal sex in maintain a temperature of 2 to 3° below body temperature which is essential for normal development of sperm.
The compartments are filled with a series of coiled tubes called seminiferous tubes where the sperm or formed and begin to mature . The sperm leave these tubes via the epididymus tube and enter the third section tubing called the vas deferents open (sperm duct)
It takes 60 days to produce basic sperm in the seminiferous tubes and another 10 to 14 days for them to mature as they move through the epipidymas and vas deferens taking a total of 70 to 74 days to complete
Explain the prostate gland
The prostate gland makes secretions which contain fructose and other sugars supplying the sperm with a source of energy
The vas deferens past the the prostate gland and secretions make up a large proportion of Seminole fluid (semen)
Explain the seminal vesicle
A gland that produces sugars and fluids to make up the seminal fluid
Explain the urethra
The urethra carries urine and Seminole fluid out of the penis, but not the same time of valve makes sure that you want at the same time
Explain Seminal fluid
Seminal fluid is comprise of sperm and secretions of various glands in the reproductive tract and ejaculated into the vagina at the serve during sexual intercourse at a volume of 1.5 to 5 CM cubed
Semen is slightly alkaline at 7.1 pH higher. This helps neutralise the acid fluid in the vagina although sperm cannot move in an acidic environment. The alkaline pH of Seminole fluid along with the alkaline mucus produced by the cervix at time of ovulation is key to sperm being able to function and move to the ovum?
Explain the penis its structure and the autonomic nervous connection
The penis transfer sperm from the body of a man into the reproductive system of a woman
It contains both spongy and reptile tissue and the number of blood space (venous sinuses) which can fill up with blood increasing blood flow and making the penis erect
Penal erection is parasympathetic nerve reflex originating high sentences of the brain however may also be triggered by stimulation of the skin and genital region
Upon ejaculation, sperm and semi fluid is ejaculated from the urethra into the vagina
Describing explain the male sex hormone
Testosterone is the mill sex home and produced in the testes is essential for development of male sexual organs, production of sperm and seminal fluid
It is needed for the development of maintenance of male secondary sex characteristic such deep voice, facial body hand, male body shape
Testosterone is anabolic steroid and stimulates both bone and muscle development
For fertilisation to occur, what is the optimum window?
For fertilisation to occur sperm must enter the vagina between five days before and one day after ovulation
Ovulation being the release of the egg from the ovary into the fallopian tubes where it can be fertilised the time scale is five days as sperm can remain fertilising capable for five days in the vagina although the ovum remains viable between 12 to 14 hours
What is the average sperm per centimetre cubed?
15 to 200,000,000 sperm per CM
Explain the process of capacitation
Capacitation is the reason why sperm cannot fertilise an egg until they have been in the female reproductive system for several hours as they need to be acted on by the secretions in the uterine tract
The process appears to remove Seminal fluid from the sperm and alter the plasma membrane enabling the surface membrane to bind with the egg
Explain the rule of acrosomes once the sperm has reached the egg and has been acted on by capacitation
Acrosomes call a cup like structure on the head of the sperm that contain digestive enzymes that help break down the zona pellucida of the egg which takes 20 minutes the first phone to penetrate the entire zone and reach the plasma membrane fuses with the membrane itself the head of the sperm passing through to the cytoplasm and the tail being left behind
Explain the set of events that happens to create a zygote open until it’s implantation into the endometrium
Once the spam has fertilise ovum it forms a zygote as well as a fertilisation membrane which consist of enzymes that prevent penetration of other sperm into the egg
A few hours after the fertilisation the zygote divides by meiosis or secondary meiotic division remaining in the oviduct for 3 to 4 days dividing by mitosis
The ball of cells forms a blastocyst and eventually the smooth muscle in the uterine tube relaxes due to increased progesterone levels and the early embryo is allowed to enter the uterus where it will be implanted into the endometrium
Describe the development of an embryo into a fetus
Development of an Embryo into a Fetus – Flashcard Format
- Fertilization (Day 0)
• Sperm fertilizes the egg in the fallopian tube, forming a zygote (single-cell embryo). - Cleavage (Days 1–3)
• Zygote undergoes rapid mitotic divisions → becomes a morula (solid ball of cells). - Blastocyst Formation (Days 4–6)
• Morula develops into a blastocyst (fluid-filled structure).
• Implantation occurs in the uterus around day 6–7. - Gastrulation (Week 3)
• Formation of three germ layers:
• Ectoderm → Skin, nervous system.
• Mesoderm → Muscles, bones, heart, blood.
• Endoderm → Digestive & respiratory systems. - Neurulation & Organogenesis (Weeks 4–8)
• Neural tube forms → develops into brain & spinal cord.
• Heart begins beating (~Week 4).
• Major organs & limbs start developing. - Fetal Stage (Week 9–Birth)
• Embryo is now called a fetus.
• Growth & maturation of organs, muscles, and bones.
• Brain development accelerates.
• By Week 12, reflexes develop, and sex organs form.
• By Week 24, lungs develop but aren’t fully mature.
• By Week 37+, fetus is full-term and ready for birth.
Let me know if you want a deeper breakdown of any stage!
What is the sack that the fetus is held in called?
The amniotic sac contains amniotic fluid which supports a development of the fetus protect protect from damage
Explain the role of placenta
Role of the Placenta – Flashcard Format
• Definition: A temporary organ that develops during pregnancy to support the fetus. It’s at touches to the uterus to the fetus via the umbilical cord.
• Function: Facilitates the exchange of oxygen, nutrients, and waste between mother and fetus.
Key Roles:
1. Gas Exchange
• Transfers oxygen from mother to fetus.
• Removes carbon dioxide from fetal blood.
2. Nutrient Supply & Waste Removal
• Delivers glucose, amino acids, fatty acids, and vitamins.
• Eliminates fetal urea, uric acid, and CO₂.
3. Hormone Production
• hCG (human chorionic gonadotropin): Maintains corpus luteum → continues progesterone production.
• Progesterone: Maintains uterine lining, prevents contractions.
• Estrogen: Promotes uterine growth and blood flow.
4. Immune Protection
• Transfers antibodies (IgG) from mother to fetus for passive immunity.
5. Acts as a Barrier
• Blocks some harmful substances but not all (e.g., alcohol, nicotine, drugs can pass).
