Body systems unit 3
what is homeostasis?
the tendency for an organism or cell to maintain a constant internal environment within tolerance limits.
What physiological processes help maintain internal equilibrium?
Body temperature, carbon dioxide concentration, blood pH, blood glucose levels, and water balance
How is homeostatis controlled? (feedback)
Homeostasis is controlled by negative feedback. Conditions are brought back to a set value as soon as it is deected that they have deviated from it. When specializeed receptors detect an internal change, a response is generated to correct it, when returned to normal, the effector ceases to generate that response. (on graph it looks like a bunch of zigzags that slowly get smaller)
What system are hormones produced from?
Hormones are chemical susbstances produced and secreted from the endocrine glands (in the endocrine system). The hormones carry messages around the body through the bloodstream.
Hormone and target cell specificity
Secreted hormones act on target cells to elicit a response. Each target cell contains specific receptor proteins for various hormones. Once it binds to the receptor it triggers other reactions within the target cell. The hormone combines with the receptor the same way a key fits a lock.
Examples of endocrine glands
the pancreas, adrenal gland, thyroid gland, pineal gland, the gonads (ovaries + testes). Neuroendocrine glands include the hypothalamus and pituitary gland, which link the nervous and endocrine systems.
What are control centers?
areas deep inside the brain that establish interactions between external or internal stimuli and bodily functions, as well as they endocrine system. They are an interface for homeostatic control.
What is the hypothalamus?
The section of the brain that links the nervous and endocrine systems in order to maintain homeostasis. It receives info from nerves in the body and other parts of the brain and initiates endocrine responses. It secretes neurochemicals (releasing factors) into a portal system which stimulates or inhibits the pituitary gland. It also secretes hormones directly into the bloodstream via neurosecretory cells that extend into the pituitary gland.
What is the pituitary gland?
It lies adjacent to the hypothalamus and is direct contact with it due to the protal blood system. It controls the secretion of other endocrine glands (master glands). It gets its instruction from the hypothalamus and consists of two lobes.
What is the anterior lobe (adenohypophysis)?
a lobe in the pituitary gland that releases hormones in response to stimulation by hypothalamic releasing factors. It is on the left side of the pituitary gland and contains endocrine cells as well as capillary beds. Hormones it releases includes thyroid stimulating hormones, protactin, growth hormones, and gonadotropins.
What is the posterior lobe (neurohypophysis)?
the lobe in the pituitary gland that releases hormones produced by the hypothalamus itself via neurosecretory cells. It is on the right side of the lobe and creates hormones like oxytocin and antiduretic hormone.
What are tropic hormones?
Hormones that target endocrine glands to secrete other hormones.
How does the process from hypothalamus to endocrine gland work?
The hypothalamus regulates the pituitary gland. It receives signals from sensors in the body and secretes releasing hormones. These hormones stimulate the pituitary gland to secrete other hormones that act on other endocrine glands.
Why is blood glucose regulated?
High levels of glucose in the blood can damage cells, making it necessary for glucose to be regulated even if needed to make ATP
How is blood glucose regulated?
Pancreatic cells monitor blood glucose. Absorption of glucose from digestion in the intestine increases blood sugar. Glucoregulation is an example of negative feedback, and uses the hormones insulin and glucagon.
If glucose is too high:
- insulin is released from beta cells of the pancrease to cause a decrease in blood glucose concentration
- this involves the stimulation of glycogen synthesis in the liver (glycogenesis), which promotes glucose uptake by the liver and adipose tissue, increasing the rate of glucose breakdown (increasing cell respiration rates)
When glucose is too low:
- glucagon is released from alpha cells of the pancreas and cause an increase in blood glucose concentration
- this involes the stimulation of glycogen breakdown in the liver (glycogenolysis), which promotes glucose release by the liver and adipose tissue, reducing cell respiration rates and the rate of glucose breakdown.
What is an exocrine gland?
A gland which releases its products into a duct (e.g digestive enzymes)
What is the effect of insulin on target cells?
Insulin causes migration of membrane proteins and absorption into the cell
What is the effect of glucagon on target cells?
glucagon causes breakdown of polymer storage products in the liver.
effects of glucose imbalance (Diabetes)
Diabetes melitus is a metabloic disorder caused by high blood glucose over a prolonged period. The body either does not produce insulin (type I) or fails to respond to insulin production (type II). Glucose stays in the blood after meals instead of entering the cells, causing a high blood sugar. Having cells without glucose results in fatigue and using fat and protein for metabolic energy. Glucose is excreted in the urine. Over time, the eyes, nerves and kidneys are damaged, and severe infection (gangrene) can occur in the limbs.
Causes + risk factors of Type I diabetes
Type I diabetes results from a failure of insulin production by the beta cells due to an autoimmune disease which destroys the beta cells in the pancreas. This is caused by genetics, environment factors, and auto-immune factors that are not well understand. Symptoms are increased thirst & urination, kidney failure, constant hunger, weight loss, blurred vision and nerve damage. It affects children and young people.
Causes + risk factors of type II diabetes
type II diabetes is the inability to process or respond to insulin due to a deficiency of insulin receptors or glucose transporters on target cells. It is caused by lifestyle (obesity, bad diet, no excercise), genetics, and aging. Symptoms include fatigue, slow healing, pain, and numbness in hands. It affects older people.
treatment for type I diabetes
treament includes injections, oral medicine, dieting and excercise, as well as blood glucose monitoring. Injections are mostly done pre-meal time to prevent a peak of blood glucose when food is digested.
treatment for type II diabetes
treatment includes diet, excercise, and blood glucose monitoring (sometimes insulin injections + oral medicine). Sugar should be avoided, and starchy food should only be consumed if it has a low glycemic index (digested slowly)
What are circadian rhythms?
they are controlled by a biological clock within the brain. This rhythm is a 24-hour cycle & continues even if a person is placed experimentally in continuous light or darkness. This rhythm is controlled by melatonin.
What are suprachiasmatic nuclei (SCN)?
they are groups of cells in the hypothalamus of the brain which set a daily rhythm. They control the secretion of the hormone melatonin by the pineal gland. When the retina us stimulated through expose to light, the release of melatonin is inhibited.
What is melatonin
Melatonin is a hormone produced by the pineal gland in darkness. It targets the pituitary and other glands, and synchronizes the circadian rhythms including sleep timing and blood pressure regulation. Melatonin secretion increases at night and slows down at dawn. One of the effects is the sleep-wake cycle. High melatonin levels cause drowsiness while lower levels encourage waking. Melatonin receptors are also in the kidneys, suggesting that decreased urine production at night may be another function of this hormone.
Melatonin effects on graph
Melatonin starts to rise as the pineal gland begins to produce melatonin in the evening. Melatonin levels peak in the middle of the night, and then they decrease as melatonin declines in the daytime.
Melatonin effects throughout the body
Melatonin is:
released from white blood cells and helps regulate the immune system
released in the retina, can regulate cell growth locally
able to protect skin cells against UV damage and regulate skin pigmentation
a general antioxidant and has cell-protective properties
able to dilate and contract blood vessels
able to inhibit the release of insulin from beta cells in the pnacreas
controls the timing of other functions with its day/night rhythm
regulates hormone release (esp for reproduction + sexual maturation)
What is jet lag?
condition caused by travelling rapidly between time zones, includes sleep disturbance, headaches, fatigue and iritability. jet lag is caused by the pineal gland continuing to set a circadian rhythm for the point of origin rather than the current time zone.
What are the adrenal glands?
they are a pair of organs involved in regulating stress response and blood sugar levels. They are located on top of the kidneys. Each adrenal gland is composed of the adrenal medulla (inner layer) and the adrenal cortex (outer layer), which each produce different hormones and function as independent organs.
How is the short-term stress response regulated?
the adrenal medulla secretes epinephrine and noepinephrine, which regulate the fight-or-flight response. The sympathetic nervous system neurons send a signal from the hypothalamus to the adrenal medulla to produce the hormones and an excitatory neurotransmitter. This causes an increase in breathing and heart rate, blood pressure and flow, glycogen conversion to glucose, and pupil dilation. Epinephrine is fast-acting and therefore used in life-threatening conditions.
Chemoreceptors and the control of the heart rate
heart rate is controlled by the autonomic nerbous system, which responds automatically to changes in body conditions. When excercising, mor co2 is in the blood, which is detected by chemoreceptors in the medulla oblongata. A nerve signal is sent to the SA node to speed the heart rate. The vagus nerve reduces heart rate when co2 levels fall.
Baroreceptors in control of the heart beat
Nerves supplying the cardiovascular centre bring impulses from stretch receptors (baroreceptors) located in the walls of the aorta, the carotid arteries, and the wall of the right atrium. When change in blood pressure is detected, the rate of heartbeat is either lowered by impulses via the vagus nerve (too high), or increased via the cardiac nerve (too low)
How do chemoreceptors control feedback of ventilation rate?
chemoreceptors in the arteries monitor blood pH, determine by the co2 concentration in the blood and communicate with the brainstem (medulla and pons). If blood pH is low, breathing becomes deeper and more frequent.
How is peristalsis controlled?
as food passes along the gut, secretions are added to it from gland cells in the stomach and from the pancreas into the small intestine. Enzymes in these secretions hydrolyze the molecules so that they can pass through the epithelium cells that line the gut. Food is mixed with enzymes from the pancreas under the action of muscles. The mass of food is moved along the digestive tract under the subsequent contraction of circular and longitudinal muscles in the wall of the small intestine (peristalsis)
Mechanism of swallowing
The first phase of swallowing (from mouth to pharynx) is voluntary and controlled by the cerebral cortex. The remaining phases are involuntary and controlled by the medulla oblongata and coordinated by the enteric nervous system. Food touches the walls of the pharynx (stimulus), which touches the receptors in the walls of the pharynx (receptor). The parasympathetic nerves send impulses via the swallowing centre in the medulla oblongata, causing a contraction of muscles in the pharynx and esophagus (peristalsis).
What is thermoregulation?
Control of core body temperature to keep it close to a set point (can differ at different times of the day, year, organism, etc). Negative feedback is the basis of thermoregulation.
How is body temperature monitored?
By peripheral thermoreceptors in the skin and central thermoreceptors in the core of the body and hypothalamus. The hypothalamus regulates them by taking in information by thermoreceptors and initiates responses.
heat generation via metabolism
Heat is generated by metabolism in cells, and then distributed by the blood circulation. Some organs are more metabolically active (e.g heart, lungs, kidneys, brain). Metabolic rate can be decreased or increased to adjust amount of heat generation.
How is metabolic rate increased?
The hypothalamus secretes thyrotropin releasing hormone (TRH), which activates the pituitary gland to release thyroid stimulating hormone (TSH), which in turn stimulates thyroxin (T4) production by the thyroid gland. Thyroxin in the blood stimulated oxygen consumption and increases the metabolic reactions that generate heat as a waste product.
Adipose Tissue and insulation
Adipose tissue acts as an insulator and reduces heat loss. Brown adipose tissue can generate heat at a rapid rate. Small mammals and newborn babies have larger quantities of this type of adipose tissue, as they are particularly prone to heat loss.
How does sweating allow for a decrease in temperature?
Hydrogen bonds broken in water molecules through evaporation need energy. Energy taken to break these bonds are removed from the body, reducing temperature.
How does vasodilation lower body temperature?
Vasodilation is the widening of blood vessels. Blood vessels become wider and move closer to the skin's surface, resulting in heat to be transported away easier (conduction and convection)
How does vasoconstriction allow for increasing body temperature?
vasoconstriction is the narrowing of blood vessels. Blood vessels become more narrow and deeply burried inside the muscle tissue. This will remove the blood flow from the surface of the skin, and therefore reduce heat loss through the skin.
What is asexual reproduction
There are no gametes formed. The offspring is essentially a clone. Examples include binary fission, mitosis, budding, fragmentation, vegetative reproduction, parthenogenesis.
What is the product of sexual reproduction?
haploid gametes are formed, which during sexual intercourse and fertilization form again a diploid zygote.
Differences between male and female gametes in sexual reproduction
Males: travel to the female, smaller and faster, only enough food reserves for the gamete, large numbers are produced.
Females: gametes are non-motile, larger due to large food reserves for embryo development, few are produced.
Pros and cons of sexual reproduction
Pros: genetic recombination allows for adaptivity, offspring are widely dispersed (e.g oceans)
Cons: need a mating partner, sexual products are small, often is seasonal, more time is invested in parental care
Pros and cons of asexual reproduction
pros: no need to locate mate, large number of offspring created, individduals are perfctly well adapted if conditions are optimal, may occur non-seasonally
cons: no genetic recombination, offspring usually locally dispersed
What are the testes?
where sperm cells begin their development. It produces millions of sperm every day, as well as testosterone.
What is the scrotum?
a sac-like structure that contains the testes. One function of the scrotum is to house the testes outside the main body cavity, a location that is cooler than normal body temperature, which is optimum for sperm production.
What is the epididymus?
Where sperm complete their development and are stored in along, thin, coiled tube attached to each testis. Sperm mature here and become able to move. Sperm stored awaiting ejaculation.
What are the seminal vesicles, prostate gland, and bulbourethral glands?
They secrete fluids that function in the transport and survival of sperm: semen. The seminal vesicle adds nutrients for respiration and mucus for protection. The prostrate adds alkaline fluids that neutralise vaginal acids. The urethra delivers semen and urine during ejaculation and excretion.
What is the vas deferens?
They are the connecting ducts. Muscular contractions propel sperm from the epididymis through the urethra.
What is the penis?
an organ consisting mainly of specialized tissue called erectile tissue. Filling of this tissue with blood causes an erection.
How do seminiferous tubules work? + testes structure
These tubules make up the testes and are where sperm is produced. From puberty the tubules produce sperm cells throughout the life of a man. They are lined by germinal epithelial cells which divide repeatedly and give rise to the spermatozoa (sperm cells). The tubules lead to the epidydmis, a much coiled tube which leads to the sperm duct. Sertoli cells provide nutrients to the developing sperm. Between the tubules is connective tissue containing blood capillaries and interstitial cells (leydig) which secrete testosterone.
Process of spermatogenesis
Mitosis produces more spermatogonia (some return to basement membrane), some grow to become primary permatocytes. FSH stimulates Meiosis I in the seminiferous tubules. It also stimulates the sertoli cells to provide nourishment for the sperm. LH stimulates the leydig cells to produce testosterone which stimulates Meiosis II. Meiosis II produces 4 haploud spermatids and testosterone stimulates differentiation. They differentiate into sperm, causing tail development and a midsection with mitochondria. Sperm are then stored and develop motility in the epididymis.
Structure + functions of sperm
It is one of the smallest human cells, the flagellum mid-piece allows for motility, and mitochondria nearby provide energy for movement. The shape is streamlined for speed and efficiency. There are very few cytoplasmic organelles. The head has a specialized secretory vesicle called the acrosomal vesicle that helped the sperm penetrate the egg's zona pellucida. Contains a haploid nucleus.
Maturation of the male reproductive system
Hromones released during puberty enable the development of sex organs and secondary sex characteristics. Gonadotropin releasing hormone (GnRH) is secreated in a fetus about 10 weeks after fertilization. It continues during pregnancy and then stops after childbirth. During puberty it restarts and continues through puberty and adulthood. GnRH triggers the anterior pituitary gland to release folicle stimulating hormone for testes growth, and lutenizing hormone for testosterone secretion.
Functions of testosterone
Stimulates spermatogenesis, stimulates secondary sex-characteristics (body hair, layrnx growth, height), growth of penis, increases secretion of body oils, and increases sex drive.
Regulation of sperm production
A negative feedback system occurs when there is a large production of FSH. Inhbin (released from tubules) and testosterone are released and act as inhibitors to the anterior pituitary gland. This maintains a constant sperm production and hormone level.
What are the ovaries?
The ovaries are where egg cells are produced. Each developing egg is contained inside a follicle. The ovaries also produce estrogen and progesterone.
What is the oviduct?
Also called a fallopian or uterine tube. It is a narrow tube about 10 cm long, which serves as a passageway to the uterus. It is the site of fertilization.
What is the uterus?
the uterus is a hollow, muscular organ with thick walls. If an egg is fertilized by a sperm cell, the uterus functions to contain and protect the developing baby. The muscular walls contract to help with the birthing process.
What is the cervix?
the cervix connects the uterus to the vagina. It is a muscular opening/entrance. When an egg is fertilized, the cervix closes to protect the developing fetus and opens to form the birth canal.
What is the vagina?
The vagina receives the penis and sperm during intercourse, is the birth canal thorugh which the baby exits, and a passageway for menstural flow.
What is the germinal epithelium?
It is an outer layer of cells in the ovary.
What are the primary follicles?
The primary follicles contain the primary oocyte, surrounded by a single layer of supporting follicle cells (much smaller than mature follicle).
What are mature follicles?
Mature follicles contain the secondary oocyte, ready for ovulation.
What is the secondary oocyte?
it is a haploid gamete. The final stage of meiosis occurs after fertilization.
What is the medulla (ovary)?
The medulla is the central main body of the ovary, including blood bessels, lymph and nerves.
structure of the mature egg
follicle cells around the egg provide nutrients to support development, the zona pellucida (wall around egg) consists of a glycoprotein that protects the egg and prevents sperm entry, the 1st polar body will break down, the nucleus contains 23 chromosomes passed from mother to child, the cytoplasm contains nutrients for development, and the cortical granules make the zona pellucida impenetrable to sperm after fertilization to prevent polyspermy.
Process of Oogenesis
1. During fetal development, large numbers of oogonia are formed by mitosis (2n).
2. The oogonia enlarge and undergo meiosis, but stop in prophase I until puberty (primary oocytes).
3a. At puberty, some follicles develop each month in response to FSH - the oocyte completes the first meiotic division, the cytoplasm division is unequal and creates a polar body, and the secondary oocyte continues into meiosis II and halts at prophase II.
3b. Secondary oocytes develop with the follicle (ruptures once mature) and are released with small number of cells (egg) into the fallopian tube, the remaining follicle cells remain in ovary to form the corpus luteum.
4. The oocyte completes meiosis II if the cell is fertilized and another polar body.
5. the polar bodies degenerate
How and when are hormones in the female reproductive system released?
at age 9-13, the hypothalamus begins to release GnRH hormone to the anterior pituitary gland. FSH and LH are also released from the anterior pituitary gland, and are involved in the release of oestradiol (estrogen) and progesterone.
what is female FSH?
Follicle stimulating hormone is a gonadotropin (produced in pituitary and acts on ovaries) and promotes the development of follicles in the ovary
what is female LH?
the lutenizing hormone is a gonadotropin and promotes oulation and the formation of the corpus luteum.
What are estrogen and progesterone?
they are hormones first secreted by the mother's ovaries and later her placenta. In the absence of fetal tstosterone and the presence of meternal estrogen and progesterone, female reproductive organs develop. At puberty the secretion of estrogen and progesterone increases, causing primary sexual characteristic of egg release, and the development of secondary sexual characteristics such as breast enlargement, skeletal development (pelvis) and pubic hair growth.
menstrual cycle follicular phase
Happens from days 1-13. In the first 5 days, the shedding of the endometrium happens (mensturation). during the whole follicular phase, FSH increases, stimulating folliicle development. As follicle cells develop, oestradiol is secreted and stimulated endometrium development. Low levels of estrogen inhibit the release of LH.
menstrual cycle ovulatory phase
day 14. High amounts of estrogen stimulate the release of LH. LH stimulates completion of meiosis in the oocyte and causes the release of the mature egg (ovulation). The egg then moves through the fallopian tube, promoting the conversion of the follicle wall into a temporary gland (corpus luteum). Ovulation provides the female gamete once a month, causing the ovum to move down the fallopian tube by peristalsis and cilia.
menstrual cycle luteal phase beginning
the corpus luteum secretes both oestradiol and progesterone. Progesterone stimulates the endometrium and prepares the uterus to receive a fertilized egg. It prevents uterine contractions and inhibits FSH and LH
mestrual cycle luteal phase ending
Levels of FSH and LH in the bloodstream decrease due to high progesterone levels, causing the corpus luteum to degenerate. Levels of progesterone and estrogen fall as a result, meaning the extra lining of the uterus is no longer maintained (onset of menstruation). Falling levels of progesterone cause the secretion of FSH by the pituitary (positive feedback).
Uterine cycle
First half is the menstrual flow and proliferative phases - the uterine membrane breaks down during menstruation and starts to be built up again slowly. The second hal is the secretory phase - the endometrium becomes thicker and more richly supplied with blood vessels in preparation for implantation.
What happens if the egg is fertilized?
the developing embryo itself becomes an endocrine gland, secreting a hormone (HcG) that circulates in the blood and maintains the corpus luteum by keeping estrogen and progesterone high. When the corpus luteum breaks down, the placenta takes over as an endocrine gland, secreting estrogen and progesterone to prevent ovulation and maintain the endometrium.
process of fertilization
1. the sperm pushes through follicular cells and binds to receptors in the zona pellucida
2. enzymes are released from the acrosome and digest the glycoprotein based zona pellucida
3. The membranes of the sperm and ovum fuse, stimulating vesicles to release proteases into the zona pellucida which causes it to harden and become impenetrable to subsequent sperm, and an influx of ca2+ into the ova which prompts the completion of meiosis II
4. the nucles of the sperm cell is deposited into the ovum's cytoplasm and fuses witht he ovum's nucleus to form a diploid zygote.
What is a blastocyst?
a blastocyst is a fluid filled cavity in the middle of the morula after continuous division (morula - ball of cells formed after series of mitotic divisions). The blastocyst contains an inner mass of cells (develops into embryo), an outer layer (develops into placenta) and a fluid filled cavity.
how does a blastocyst get implanted?
the formation of the blastocyst is in the fallopian tubes and uterus prior to implantation. When it reaches the uterus, it will embed itself in the endometrium. The developing embryo will gain nutrients and oxygen from the endometrium fluid (supplied by capillary network). The implantation of the blastocyst causes the formation of the placenta, connecting the fetus to the maternal uterus. Tissue cells differentiate, allowing for the development of membranes (amnion + chorion) as well as the yolk sac. Invading blood cells establish fully functional umbilical cord vessels.
How does pregnancy testing work?
Pregnant women have high hCG conentration. Antibodies to hCG are engineered to carry colored granules. ELISA tests indentify hCG based on the colour change. Free monoclonal antibodies specific to hCG are conjugated to an enzyme that changes the colour of a dye. A second set of antibodies are immobilized ot the dye substrate. if hCG is present in urine, it will interact with both antibody sets, bringing the enzyme into physical proximity of the dye and changing its colour. A third set of antibodies bind to any unattached enzyme-linked antibodies, functioning as a control. No control line means test is faulty.
How is the placenta structured?
the placenta is a disc shaped structure that nourishes the fetus. It is formed from development of the trophoblast and eventually invades the uterine wall. Maternal blood pools via open ended arterioles intervillous spaces within the placenta (lacunae). Chorionic villi extend into the blood pools, mediating material exchange from the villi to the fetus from the umbilical cord.
How does material exchange in the placenta work?
chorionic villi are lined by microvilli to increase availlable surface area for material exchange. Fetal capillaries are close to the villi to minimize diffusion distance from the blood in the lacunae. Oxygen, nutrients, vitamins, antibodies and water go to the fetal capillaries. Fetal waste (co2, urea, hormones) go into the maternal blood vessels.
Hormonal roles in the development of the fetus
the placenta takes over the hormonal role of the ovaries (12 weeks) and produces estrogen and progesterone. Estrogen stimulates the growth of uterine muscles and the devlopment of the mammary glands. Progesterone reduces contractions, maternal immune responses, and maintains the endometrium. Both estrogen and progesterone levels drop near the time of birth.
What is the amnion?
the amnion is the membrane that encloses the anmiotic fluid, and is ruptured before birth.
what is the amniotic fluid?
fluid that protects the etus against mechanical shock, drying out and temperature fluctuations.
The amniotic sac functions + purpose
fetus develops in a fluid filled space encolses by the amniotic sac. It functions as a barrier against infections, absorbs pressure, creates buoyancy so the fetus doesn't have to support its own weight while the skeletal system develops, and prevents the dehydration of fetal tissues.
hormonal role in labour/childbirth
stress caused by the fully grown baby stretching the uterus walls induces the release of chemicals that trigger a rise in estrogen. Estriol (estrogen) increases responsiveness of the uterus walls to oxytocin by increasing oxytocin receptor numbers. It also inhibits progesterone (was proventing contractions). Stretch receptors on the uterus trigger the release of oxytocin from the posterior pituitary gland, causing muscle contraction and inhibiting progesterone. The fetus responds to contraction by releasing prostaglandins, which triggers more and stronger contractions (positive feedback). Contractions stop when the baby is birthed (no more stretching).
causes of infertility in males
failure to achieve or maintain erection, structurally abnormal sperms, sperms with poor mobility, short-lived sperms, too few sperms, and a blocked sperm duct
causes of infertility in females
cervix conditions which cause sperm death, uterus conditions that prevent implantation of the blastocyst, eggs that fial to mature or be released, and blocked or damaged oviducts that prevent the egg from reaching sperms.
hysterosalpingograms
a special x-ray that can see if the fallopian tubes are blocked. A dye is infused through the cervix into the uterus, allowing it to flow into the fallopian tubes and pelvic cavity. If the woman has a clear fallopian tube, dye will come out the ends of the tubes.
steps of in vitro fertilization
Down regulation: drugs halt the secretion of FSH and LH (stops estrogen and progesterone production), drug treatment takes 2 weeks and is delivered in the form of nasal spray. Quantity and timing of egg prodcution is controlled
superovulation: large amounts of FSH are injected to stimulate development of many follicles. Follicles are treated with hCG, stimulating the follicles to mature and then an egg is collected (aspiration needle) prior to follicles rupturing.
Fertilization: extracted eggs are incubated in the presence of sperm sample and then analyzed to make sure it's successful
implantation: two weeks prior, woman takes progesterone to develop the endometrium. Healthy embryos are transferred into the uterus (multiple inserted for improved chance). two weeks after, a pregnancy test is taken to determine if it has been successful
What is menopause?
a decrease in estrogen and progesterone results in the end of menstrual cycles. The amount of functioning follicles has decreased, causing a decline of the hormones in the blood. Symptoms include blood vessels alternately constricting and dilating (hot flashes), mood changing, rising cholesterol levels, diminishing bone mass, and increase risk of uterine cancer, breast cancer, and heart disease
what is HRT?
Hormone replacement therapy is used to alleviate symptoms of menopause. Typically estrogen, progesterone, and testosterone are used. Side effects include hair loss, fatigue, breast tenderness, joint pain, and possible risk of coronary heart disease.