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