Final Exam Notes Flashcards
Peritubular capillaries
Surround the nephron so that you can do exchanges between the filtrate that is in the nephron and the blood
Vasa Recta
Peritubular capillaries that surround the loop of Henle
Glomerular Filtration Rate
GFR
Typically about 115-125 ml/min; thats all of them together; that’s how much filtrate you are making per minute
How do you increase your glomerular filtration rate?
By vasodilating the afferent arteriole to have higher blood pressure in blood capillary; you don’t have as much as a pressure drop in the blood vessel; so if you want to increase your GFR you want to increase your blood flow so you dilate the afferent arteriole
How much filtrate gets reabsorbed in the proximal tubule?
About 65% of GFR
What is the job of the distal tubule?
To regulate the salt content of filtrate
The pumping in the proximal tubule is predominantly
A sodium pump
What is the function of the Loop of Henle?
To create a concentration gradient so that the interstitial has a greater osmotic concentration as you move down the tubule. It does not concentrate the fluid
If we are hydrated what do we want for the walls of our collecting duct?
You want them to be impermeable to water so you can get rid of the excess fluid
If we are dehydrated what do we want for the walls of our collecting duct?
We want to save our fluids so we will make the walls of the collecting duct as permeable as possible
How do we adjust the permeability of the collecting duct?
We use the Antidiuretic Hormone
Comes from the Posterior Pituitary Gland
The neurons carry axons down to the pituitary
Antidiuretic causes you to retain water; makes the collecting duct more permeable so water moves out. If the osmotic concentration falls, that inhibits ADH secretion. If the osmotic concentration of your blood rises, that means you lost water, that means your blood is more concentrated than it should be, so you stimulate the production of ADH secretion. If you are dehydrated the ADH won’t make you hydrated again, it will just help you hold onto your water.
How does the Loop of Henle set up a concentration gradient?
The thick ascending limb is impermeable to water and solutes & there’s all types of mitochondria in these cells and ion pumping; sodium ions being pumped out. The thin descending limb of loop of henle is permeable to solutes and water. Fluids primarily will leave the filtrate, making the inside more concentrated. About 20% of the fluid that you produce from the glomerulus is reabsorbed as the filtrate goes through the loop of henle
Job of the Distal Convoluted Tubule
Job is to regulate salt; sodium in the body
Are active transport pumps that pump out sodium
Na+/K+ coupled pump
Hormone Aldosterone
Regulates ion pumping in the distal tubule. Without aldosterone 80% of the remaining Na+ is reabsorbed. With aldosterone 100% of the remaining Na+ can be reabsorbed & potassium will be secreted from the blood to the filtrate. In order to get rid of excess potassium, you need some aldosterone. Also good when your sodium levels are low. Secreted by Adrenal Cortex. Stimulated by high blood [K+], low sodium does NOT stimulate adrenal cortex. Is stimulated by angiotensin II.
Granular Cells
Secrete renin. Do this when the blood flow becomes too low in the afferent arteriole. The cells act like stretch receptors. If the cells are not stretched enough (e.g. low flow, low cardiac output), the granular cells will secrete renin
Angiotensinogen
A plasma protein produced by the liver that is always present in the blood. Is converted into Angiotensin I by Renin
Angiotensin II
An active enzyme in the walls of the pulmonary vessels. Acts on the adrenal cortex & acts as a vasoconstrictor. Causes aldosterone to be secreted which increases sodium pumping leading to more water to be reabsorbed so blood volume will go back up again.
Atrial Natriuetic Hormone
From right atrium. Is in response to an increase in stretching (ie: too much blood volume). It is going to help you get fluid from the body. Helps in fluid removal. Inhibits ADH so dilute filtrate just comes out. Inhibits renin & aldosterone because in combination they help bring sodium from the filtrate and water follows by osmosis and you already have too much water. Increases glomerular capillaries permeability so GFR increases. Greater filtration, greater fluid loss
Juxtaglomerular Apparatus
It is half distal tubule and half afferent arteriole. Within the afferent arterioles are granular cells which secrete renin. Within the distal tubule are macula densa cells
Granular cells
Within the afferent arterioles. Secrete renin
Macula Densa Cells
Within the distal tubule. Are responsive to sodium concentration. They inhibit the granular cells from secreting renin if the sodium concentration is too high
We secrete renin when blood volume is…
When blood volume is low you secrete renin
In our lab what happened when we drank the distilled water?
You diluted your blood by drinking distilled water. The osmotic concentration fell. Hypothalamus sensed a reduction in osmotic concentration, there inhibiting ADH secretion. You want copious quantities of dilute water that you secrete. In the heart it will cause an excess of blood volume, stretching the atria and inhibits ADH, renin, and aldosterone sequence
What happened in the lab if we had the isotonic saline
We did not alter the osmotic concentration. ADH wouldn’t immediately be affected because you didn’t change osmotic concentration but blood volume would increase which would inhibit ADH and the system. You increase copious amounts of dilute urine. The blood volume then comes back normal but without getting rid of the salts your osmotic concentration begins to rise. High sodium filtrate, sensed by macula densa cells, which inhibits renin
Mitosis
Process of making exact copy of daughter cells
How many chromosomes do humans have?
46
Prior to cell division what is the first thing chromosomes do?
make copies of themselves
Centromere
Protein material that holds 2 chromosomes together
Prophase
After the chromosomes are copied, the nucleic membrane dissolves
Metaphase
Chromosomes line up with one another in the center of the cell in no particular order. The spindle fibers form at the poles.
Anaphase
Spindle fibers begin to shorten and pull the chromatids apart towards the respective poles
When the 2 chromatids are attached by the centromere
They are a chromosome, when they are pulled apart they are called 2 chromosomes
Telophase
Chromosomes are at the poles
Cytokinesis
Follows mitosis. The actual physical dividing of the cell membrane forming 2 daughter cells
Meiosis
Reduction division. Diploid cells make haploid cells
Meiosis I
Prophase I: copy DNA, “dissolve” nuclear membrane
Metaphase I: homologous chromosomes pair up & pairs align down metaphase plate; are not breaking the chromatids from the centromere
Anaphase I: the pairs move to opposite poles
Telophase I: the pairs reach the opposite poles
Cytokinesis: gives us 2 daughter cells. Each of these daughter cells are haploid, they have 1 chromosome and 2 chromatids attached
Meiosis II
Anaphase II: break chromatids apart
At the very end we end up with 4 daughter cells that are haploid, about 1/4 of the size of the original cells that we started with. These haploid cells are called gametes.
Gametes
A set of haploid cells that fuse together with another set of cells. So if 2 gametes were to fuse they would form a diploid cell
Syngamy
The fusing of 2 gametes to create 1 diploid cell = a zygote
Spermatogenesis
Spermatogonia: the germline cells in the testes and they divide by mitosis so you get an exact copy, 2 primary Spermatocytes (both diploid cells), but we give them a different name because these are the cells that are going to go under meiosis; form secondary Spermatocytes after meiosis I (haploid cells); undergo Meiosis II to form Spermatids
T/F: The first primary spermatogonia undergo meiosis
False
The first primary spermatogonia does not go under meiosis but rather forms another spermatocyte which will go under meiosis
How many spermatids do we get for each spermatocyte that goes under meiosis?
Get 4 Spermatids (haploid cells) for each spermatocyte that goes under meiosis
Oogenesis
Creation of the eggs
Oogonia
Diploid cells that undergoes mitosis. Forms 2 primary oocytes (diploid cells).
Do both oocytes undergo meiosis?
Yes, both oocytes undergo meiosis, 1 difference between males and females
Describe cytokinesis in females & males
The cytokinesis is about equal in males but unequal in females so we get 1 big cell and 1 small cell; the smaller cell would be called the polar body and the bigger would be the secondary oocyte; the polar body does not make it, it gets recycled
How many secondary oocytes do we get from a primary oocyte?
1 primary oocyte will make 1 secondary oocyte (haploid), which is a large cell
What does the secondary oocyte undergo?
Secondary oocyte undergoes meiosis II which is also unequal Forms Ovum (haploid) and polar body; so single primary oocyte creates 1 gamete
T/F: Males can keep regenerating spermatogonia but females lose theirs
T
The biggest cell in your body is
the primary oocyte when it is mature; that way when you divide the Ovum/gamete will be large also
What does growth imply?
It is an increase in mass. Can’t occur until implantation on the uterine wall where the cell receives nutrients.
What does development imply?
Implies cell division and differentiation but no input of energy or cell size
Testes
Site of spermatogenisis
Store sperm in
Epididymus
Spermatochord
Connective tissue that surrounds the vans deferens
Prostate has a high or low pH
Has a high pH fluid
Seminiferous tubule
Where meiosis occurs and sperm are formed
Sertoli cells are also referred to as
Nurse cells, they help with spermatogenesis
Lydig cells
The interstitial cells, secrete the male sex steroid testosterone
Do the ovaducts connect to the ovary?
Ovaducts are NOT in physical contact with the ovary; they surround it but there’s no physical contact
Follicles
Ovarian tissue surrounding germ-line (oogonia) cells
Primordial follicles
Had these from birth
Primary follicles
Have grown, and they are encapsulating a primary oocyte
The primary oocyte will undergo…
Meiosis I leaving behind a secondary oocyte and a polar body
Secondary follicle
Encapsulates secondary oocyte
T/F: When the secondary oocyte is ovulated meiosis is officially complete
False, meiosis is not complete yet. It takes fertilization to finish meiosis
Corona Radiata
The cells that surround the ovulated oocyte
Zona pellucida
The non cellular material surrounding the ovulated oocyte
Graafian or Vesicular Follicle
The mature follicle that surrounds the large/ready oocyte
Approximately how long does it take to go from a primary oocyte to an ovulated oocyte?
about 2 weeks
About how long is the ovarian cycle?
28 days
About how long is the follicular phase?
About 14 days
About how long is the luteal phase?
About 14 days
Difference between corpus luteum and corpus albican?
Corpus Luteum is the functional one
Corpus Albican is the degenerating one that will restart the cycle
Follicular cells
Secrete estrodial; the female sex steroid estrogen
Lutenizing Hormone (LH)
Anterior pituitary hormone
Referred to as a gonadotropin b/c of action on the gonads
Acts on interstitial tissue causing male cells to make testosterone. Stimulate making the sex steroid. Important in sex steroids/hormones
Follicle Stimulating Hormone (FSH)
Anterior pituitary hormone
Referred to as a gonadotropin b/c of action on the gonads
Acts on sertoli cells triggering spermatogenesis. Is important in gamete production
Stimulates the follicles to growth and causes the development of more LH receptors
Gonadotropin releasing hormone (GnRH)
Comes from hypothalamus goes through portal vein to the anterior pituitary and causes the anterior pituitary cells to secrete the gonadotropins
What happens to the feedback loop if you produce too much testosterone?
If you produce too much testosterone, it inhibits the hypothalamus and the anterior pituitary so GnRH and LH won’t be produced. It inhibits FSH production
Proliferative phase of the Uterine Cycle
About 3 days into the ovarian cycle the lining of the endometrium (inner lining) on the uterus begins getting thicker. Increase in FSH causes an increase in the receptors for LH which causes more estrogen secretion so the uterus gets thicker. When at high levels of estrogen, it has a positive effect on hypothalamus to cause GnRH secretion that causes spike in LH & FSH, which triggers ovulation.
Secretory phase of the uterine cycle
When corpus luteum becomes present it gets thicker and more blood vessels come in
Menstrual phase of the uterine cycle
The uterine lining starts to atrophy
The corpus luteum produces
Estrogen - responsible for proliferation of uterine cells
Progesterone - isn’t seen until second phase when corpus luteum is present
What triggers ovulation?
More LH leads to ion pumping in secondary oocyte (Graafian follicle) causing the cell to swell and explode, triggering ovulation. The secondary follicle is completely disrupted.
What happens after explosion of follicle?
Occurs after ovulation. You have a drop off in estrogen so you go back to your baseline levels of LH & FSH. The baseline levels of LH are now responsible for the reorganization of the corpus luteum
Together high levels of estrogen & progesterone do what in terms of uterine cycle?
High levels of estrogen & progesterone together inhibit the hypothalamus so GnRH falls; therefore LH falls; therefore estrogen & progesterone levels fall; therefore uterine lining falls off
Which phase is perfect for implantation?
Middle of the secretory phase
How does pregnancy maintain the uterine lining?
The developing embryo (fetus) secretes chorionic gonadotropin (fetal hormone) which is an analog to GnRH. It acts like LH which maintains the corpus luteum and stimulates the corpus luteum to produce estrogen and progesterone in order to maintain the uterine lining. After several weeks of pregnancy the placenta is developed enough and produces estrogen & progesterone on its own (takes over the job of the sex steroid production so the corpus luteum is no longer needed)
What are you testing for in at home pregnancy tests?
Chorionic Gonadotropin - the fetal hormone
If you are 4/5 months along in the pregnancy the test will come up as negative because the placenta has now taken over the production
What happen to estrogen levels during the follicular phase?
Estrogen levels increase
What happens to the uterine lining if estrogen and progesterone levels fall off?
The uterine lining falls off and we start the menstrual cycle
How does birth control work?
It hormonally mimics pregnancy. Estrogen and progesterone in birth control pills. Together the high levels of estrogen and progesterone inhibit LH. By inhibiting LH production, birth control pills inhibit ovulation
Granulosa cells secrete
Estrogen
LH acts on
Theca cells
Precursor to estrogen
Androgen
What happens if a woman does not have enough fat?
Production of the steroids, androgen and estrogen, are derived from cholesterol through metabolic pathways so having an appropriate level of body fat impacts the production of sex steroids. If a woman does not have enough body fat, she does not make enough estrogen from the androgen precursor
Describe the link between estrogen and bones
Estrogen helps maintain your bones. Bones tend to be catabolized and not rebuilt. Estrogen promotes bone replacement.
How do you get an erection?
Job of corpus spongiosum. Engorgement of blood in the corpus spongiosum causes erection.
Describe the penile arterioles prior to sexual excitement
Normally prior to sexual excitement there is a tonic sympathetic input to the penile arterioles causing slight vasoconstriction. The blood flow in is matching the blood flow drainage
What happens to the input during sexual excitement?
Going to get a decrease in the sympathetic input and an increase in the parasympathetic input thereby causing dilation of the arterioles. Increase in heart rate, cardiac output & blood pressure due to sympathetic input, so there is an increase in blood flow. The increase in blood flow to the penis exceeds the venous drainage causing engorgement of penile tissue.
Lubrication
Sympathetic input to bulbourethral glands
Emission
Move sperm from epididymis to ejaculatory duct & secretion from seminal vesicles & prostate. Caused by sympathetic input to smooth muscles during sexual stimulation.
Ejaculation
Continual contraction of smooth muscles in urethra, combination of sympathetic & parasympathetic stimulation
Pronephros
Formed first
4th - 6th week of embryonic life
Pronephric Duct
Also known as the Wolffian duct
Amnion
Maintains shape of developing embryo. Surrounds the developing embryo. Filled with fluid. Most important in maintaining the shape of the developing embryo; support the round yolk & allows for good cleavage. Is a shock absorber for the developing embryo. Amniotic sac is what breaks when a woman’s “water breaks”
Chorion
Along with the allantois forms the placenta
Allantois
Is like a sac. Receptacle for metabolic wastes. Out pocket of the gut tube.
Yolk Sac
Yolk of a bird egg is the ovum. Humans have little yolk in their eggs because we have placental development. We already get nourishment from the mother’s blood
In males does the wolffian duct stay or disappear
Stays
Spermatogonia and Oogonia are both
First sex cells
Mullerian duct
Paramesonephric duct
What happens if you end up with testosterone being produced in development
The mullerian duct will eventually disappear. The primary sex chords grow out, surround the germline cells and become the seminiferous tubules. Seminiferous tubules connect via the rete testis with the mesonephric tubules. The wolffian duct will become the epididymis and the vas deferens. The sperm that go through the wolffian duct will end up at the urethra and go out through the same duct as the urine. The primary sex chords become seminiferous tubules which secrete testosterone and mullerian inhibitory hormone, which inhibits the mullerian duct
Down syndrome
When women are older they are more likely to reproduce a child with down syndrome
Nondisjunction
Within sex chromosomes, extra X chromosome. A problem in meiosis
Klinefelter’s syndrome
Extra X. Y chromosome has genes for creating male so normal sperm (X) or (Y). Abnormal (XX) so XXX or XXY
Turner’s syndrome
Only have one X chromosome, have female structure
Capacitation
Gain ability to fertilize an oocyte from mobile sperm
Acrosome
Contains digestive enzymes, releases enzymes when met with sperm (acrosomal reaction)
Cortical Reaction
Physical contact of sperm triggers release of cortical granules. Have chemicals that react with zona pellucida making it impenetrable to sperm. After contact, depolarizes membrane of oocyte, opens Ca+ channels trigger for exocytosis of cortical granules. The fertilization membrane derived from zona pellucida upon reaction with contents of cortical granules
What happens to the secondary oocyte after fertilization
Undergoes meiosis 2, a functional ovum with diploid zygote
Morula
Solid ball of cells after divisions of mitosis
Blastocyst
Cavity within middle of ball. Hollow ball of cells
Cytotrophoblast
Outside of ball. Has digestive enzymes that blows projections into the uterine lining and grows into finger like projections of it – fertilized egg is now attached to uterine lining
Inner cell mass
Inside of ball
Zygote development
Development of zygote–> early cleavage–> morula–> early blastocyst–> late blastocyst (takes about a week)
Ectopic pregnancy
Implantation occurs at sites NOT in uterus, high proportion of deaths of baby. Some occur outside reproductive tract, will be surgically removed during birth
Embryological tissue sites
Endoderm - forms yolk sac
Ectoderm
Mesoderm - forms last next to forming body; bones, heart, skeletal tissue
Eventually allantois - will grow out of inner margin of endodermal tissue -> out to chorion
Mesodermal cells outside embryonic body will form
blood cells
Mesodermal cells inside embryonic body will form
Blood cells and heart
Our placenta
Made out of chorion and allantois
Stages of Development
Embryonic - 0 to 9 weeks; major differentiation
Fetal - 9 weeks to 38 weeks (birth); major time of growth, some differentiation
Gestation - time in uterus
Parturition - delivery of baby
Chorionic Somatotropin (CS)
Aka placental lactogen. Acts on mother to reduce glucose uptake and stimulate lipolysis (breaks down mother’s fat) which increases the level of fatty acids in her blood; so if the mom is not using the glucose/fatty acids than it is made available to the developing baby
Chorionic Thyrotropin
Acts on the mother’s thyroid gland
Parathyroid Hormone
related peptide (PTH rp): if calcium levels get too low this breaks down the mother’s bones to provide the baby with calcium
Relaxin
breaks down much of the collagen connective tissue and softens the cervix to make it easier for the baby to pass through, also relaxes and breaks down the collagen connective tissue of the pubic symphysis, this is late into gestation; Increasing the size of the birth canal
Corticotropin Releasing Hormone
acts on fetus rather than the mother: acts on fetal anterior pituitary to produce ACTH (adrenalcorticotrophic hormone) which acts on the fetal adrenal cortex and which causes production of cortisol & DHEA. The cortisol stimulates the fetal lungs which when mature stimulate surfactant leading to an increase in the number of receptors for oxytocin
What part of the body needs to be developed enough in order for the fetus to form hormones?
Adrenal cortex
Function of cholesterol in fetal development
Mother gives placenta cholesterol; placenta converts cholesterol into progesterone which can go back into the mother; some cholesterol goes into the adrenal cortex of the fetus where if the fetus is developed enough it can create dihydroepiandrosterone (DHEA) which is converted into estrogen in the placenta and then into the mother
States of Parturition
Dilation: Cervix dilates up to 10 cm. Amniotic sac breaks. Contractions of the uterus are becoming more regular.
Expulsion of baby: Forceful uterine contractions. Abdominal muscles aid in delivery
Placental expulsion: Uterine contractions continue to constrict mother’s blood vessels so the mother does not have obsessive bleeding. After birth (placenta) is expelled
How long does it typically take for the uterus to go back to normal after birth
After birth, the uterus takes 4-6 weeks to return back to normal size; it goes by faster if the mother does not breast feed
Effects of Estrogen on the Uterus
Increases the number of gap junctions between myometrial cells → the uterus is converted to a single unit. It also increases the number of receptors to oxytocin in myometrium; low levels of oxytocin finally stimulate uterine contractions when uterus becomes sensitive enough; the contractions push the fetus on to cervix; the sensory input to hypothalamus causes an increase in oxytocin release which causes more contraction causing the positive feedback loop
How Interleukin 8 helps along with estrogen
Almost acts as an inflammatory response. Surfactant (made towards the end of gestation) in the amniotic fluid stimulates the macrophages in uterus to produce interleukin 1 which along with uterine stretching cause nuclear factor kB in uterus which causes creation of interleukin 8 which increases the number of receptors for oxytocin in uterus. So once the baby has surfactant it helps set the stage for its own delivery. Important to remember that interleukin 8 and estrogen both increase the number of receptors for oxytocin in uterus
Once the baby is born and the placenta is expelled
Estrogen levels decrease. Progesterone levels decreases. Remaining endometrium discharged (LOCHIA – the remaining endometrium expelled)
Dizygotic Twins
2 zygotes, 2 fertilized secondary oocytes. Fraternal twins
Monozygotic Twins
1 zygote. Morula (or earlier) splits in two, each develops into blastocyst → each forms placenta etc. ORR:
Blastocyst develops & then inner cell mass splits; each part develops into complete fetus but one placenta. Inner cells partially splits. Conjoined twins
Ampulla
Swelling. Reservoirs for milk
Alveolar glands
Alveoli produce the milk
Prolactin
From anterior pituitary. Secretion controlled by hypothalamus. PRH = Prolactin releasing hormone. PIH = Prolactin inhibiting hormone
Difference between prolactin levels in males and females
Brain communicator is dopamine. Present in both males & females; in males dopamine dominates over the PIH so prolactin is not formed; true for females up until puberty. In males, PIH dominates over PRH therefore no prolactin. In females, PIH dominates over PRH until puberty, then estrogen starts to rise and estrogen will enhance PRH so prolactin secretion rises
What effect do estrogen and progesterone have on milk production?
Mostly progesterone inhibits milk production. At parturition when estrogen and progesterone levels drop, there is no inhibition on milk production so milk’s produced
What effect do prolactin and chorionic somatotropin have on breast development?
The 2 act together on the breast tissue to synthesize the enzyme needed for milk production. Therefore breasts usually enlarge
Colostrum
W/o lactose. Grey, all antibodies
What impact does suckling have?
The physical withdrawal of milk is sensed, neurologically triggers releasing hormones so an increase in prolactin and an increase in oxytocin. Prolactin stimulates milk production. Oxytocin causes smooth muscle contractions in ducts “milk let down”
For breast feeding, can you stop and then go back to it later?
In order to breast feed an infant you need to keep doing it otherwise you will lose the manufacturing equipment. Mother typically makes as much as milk as the baby needs (as the baby’s suckling). Without suckling, the uterus may return to its normal shape faster
What are some advantages of breast feeding?
Immunize the child
Nourishment of child
Menopause
As the women is aging she keeps using up her oocytes so she has fewer and fewer primordial follicles and germ cells; lost every month. She is running out of follicles. Running out of source of estrogen b/c it is derived from the follicles. Lose corpus luteum. Does not have steady period. Lose good cholesterol levels; heavy chance of serious vascular diseases. Woman experience mood changes. Estrogen helps maintain bone density by stimulating osteoblasts
How does viagra work?
Parasympathetic nerves in the penis release nitric oxide (gas) instead of acetylcholine. Stimulates an enzyme (guanyl cyclase) in post-synaptic smooth muscle cells, makes cGMP which will lead to. Enzyme will catalyze a reaction which will lead to the relaxation of smooth muscle cells therefore vasodilation of the arterioles. cGMP broken down by an enzyme so vasodilation stops, so if you can block this enzyme you maintain vasodilation and your erection and wah-lah!
LH in Females
Acts to stimulate the production of estrogen
FSH stimulates the development of gametes (development of follicle, etc)
LH in Males
Responsible for testosterone production
