GU PHYS Flashcards
What are the functions of the kidneys?
Regulation of water, inorganic ion balance, and acid base balance (in cooperation with the lungs)
Removal of metabolic waste products from the blood and their excretion in the urine
Removal of foreign chemicals from the blood and their excretion in the urine
Glucogeneogenesis
Production of hormones and enzymes
What hormones and enzymes do the kidneys produce?
Erythropoietin, which controls erythrocyte production
Renin, an enzyme that controls the formation of angiotensin, which influences blood pressure and sodium balance
Conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D, which influences calcium balance
What are the major functions of the Glomerulus/Bowman’s capsule?
Forms ultrafiltrate of plasma
What are the controlling factors of the Glomerulus/Bowman’s capsule?
Starling forces (Pgc, Pbs, pie GC)
What are the major functions of the proximal tubule?
Bulk reabsorption of solute and water
Secretion of solute except K and organic acids and bases
What are the controlling factors of the proximal tubule?
Active transport of solute with passive water absorption
Parathyroid hormone inhibits phosphate ion reabsorption
What are the major functions of the loop of henle?
Establishes medullary osmotic gradient at the juxtamedullary nephrons
Secretion of urea
What are the major functions of the descending loop of henle?
Bulk reabsorption of water
What are the controlling factors of the descending loop of henle?
Passive water reabsorption
What are the major functions of the ascending loop of henle?
Re-absorption of sodium and chloride
What are the controlling factors of the ascending loop of henle?
Active transport during reabsorption by co-transport
What are the major functions of the distal tubule and cortical collecting ducts?
Fine-tuning of the reabsorption and secretion of small quantities of useful solute remaining
What are the controlling factors of the distal tubule and cortical collecting ducts?
Aldosterone stimulates sodium reabsorption and K secretion
PTH stimulates calcium ion reabsorption
What are the major functions of the cortical and medullary collecting ducts?
Fine-tuning of water reabsorption
Reabsorption of urea
What are the controlling factors of the distal tubule and cortical collecting ducts?
Vasopressin increases passive reabsorption of water
What are the muscles of micturtion and their innervation?
Define micturition
urination
Describe the process of micturition
Full bladder stimulates spinal reflexes
Detrusor muscle contraction
Inhibition of sympathetic input and opening of internal/external urethral sphincters
What is a trigone?
Common sites of persistent UTIs
The pontine control centers mature between ages 2 and 3, what are the two stages?
Pontine storage center and pontine micturition center
What is the pontine storage center?
Inhibits micturition
Inhibits the parasympathetic pathways
Excites sympathetic and somatic efferent pathways
What is the pontine micturition center?
Promotes micturition
Excites parasympathetic pathways
Inhibits sympathetic and somatic efferent pathways
How is urine created?
The glomerulus and Bowman’s capsule both sit inside the renal corpuscle. The glomerulus is actually finistrated by surrounding podocytes with arterieies and they have little slits that can allow SMALL solutes to go through. If it is allowing bigger things like protein to go through, thats a problem. The yellow image in the outline of how things occur in the glomerulus
What are the two types of nephrons and their functions?
Some sit in the cortex (aka cortical nephrons)
Some sit in the medulla (aka juxtamedullary nephrons) sit lower and deeper into the medulla and next to the vasa recta. The vasa recta help set up the osmotic gradient of the loop of henle to be able to reabsorb water. Aquaporons provide little openings here for water to flow out of the nephron and into the medulla and then into the blood. The vasa recta has many many solutes that sets up a gradient that gets higher as we get closer to the medulla.
What are the 3 forces of glomerular filtration and their net gives us, what value?
glomerular capillary hydrostatic pressure (pushing fluid out)
capsular hydrostatic pressure (opposing filtration)
blood colloid osmotic pressure (opposing filtration)
The net of these give us our GFR.
How is the anatomical makeup of the renal capsule sufficient physiologically to carry out the kidneys necessary functions?
We have our afferent arteriole coming and a podcytes around the arteries and the efferent arteriole tha exit. Sitting really close to these arterioles is actually the loop of henle. The nephrons aren’t nice and straight, they curl around. The ascending loop of henle kind of wraps around and creates this band of specialized cells and tissue fibers that form what we know as the macula densa and the walls of the glomerulus also actually have juxtaglomerular cells.
What is the name of the macula densa and the juxtaglomerular cells together?
The juxtaglomerulur complex. Cells from the glomerulus and cells from the loop of henle form this apparatus.
What is the function of the juxtaglomerular complex?
Regulate ion, water balance, and blood pressure
What are the functions of paratubular capillaries?
They set up a gradient just a little in addition in the cortex, but not as much as the vasa recta
What is the flow of blood through the nephron again and what forces are applied?
Our afferent arteriole comes in, blood is filtered through the combination of pressures. Then blood is secreted, because through out the nephron, we can actually push things into and pump things into the nephron and we can also reabsorb things.
Remember filtration occurs in the glomerulus
Secretion and reabsorption happens in the tubule
The sum of these three processes actually equals what come sout of the nephron (urinary excretion).
What are the forces involved in filtration?
Hydrostatic pressure in the capillaries forces filtrate into bowmans capsule. The two opposing forces are hydrostatic pressure in the capsule and oncotic pressure is the pull of proteins. The sum of these gives us our net GFR.
What is the glomerular filtration rate?
Volume of fluid filtered from the glomeruli and Bowman’s space per unit of time
What are some ways we can increase and decrease GFR?
Proteins
Obstruction of the nephron
When a patient has diarrhea, they are using water and sodium, so their plasma volume drops and their venous pressure drops. What happens in the kidney to combat this?
A decrease in venous pressure means a decrease in venous return and decreased atrial pressures. Decreased baroreceptor activity and stretch on the heart. Everything is decreased on the left. The sympathetic nervous system in the kidneys is activated and so we will have constriction of the afferent renal arteriole to let less blood into the renal glomerulus, by letting less blood in, we are decreasing our hydrostatic pressure and filtration. Therefore we don’t want to make more urine, this is how sodium and urine output decreases.
How would a well hydrated person’s GFR be different from someone who is dehydrated?
Higher blood volume → better renal perfusion.
Leads to increased renal plasma flow (RPF).
This supports a higher or normal GFR.
The afferent arteriole is typically vasodilated, allowing more blood into the glomerulus, and enhancing filtration.
What does passive diffusion for sodium and water reabsorption look like?
How do we use passive diffusion in the kidneys?
Urea secretion
Where are glucose molecules absorbed?
Movement of substances from apical (between tubular lumen and cell) or basolateral membrane (interstitial space next to the capillaries and the cell)
How does glucose play a role in the mediated transport of ions in the kidneys?
Glucose may get left behind in the tubular epithelial cell and lead to Glycosuria and transport maximum causing osmotic diuresis. This causes a lot of water reabsorption, because glucose attracts water, so they will have a lot of glucose in their urine, but they will also have to pee a lot (polyuria). They also tend to get really dehydrated (polydypsia, polydysphagia)
What are the components of nitrogenous wastes?
- Urea from amino acid breakdown and it is the largest solute component
- Uric acid from nucleic acid metabolism
- Creatinine from the metabolite of creatinine phosphate
- Other normal salts found in urine include sodium, K, phosphate, sulfate, Calcium, magnesium, and bicarb
Abnormally high concentrations of any constituent or abnormal components such as blood proteins, white blood cells, bile pigments, may indicate pathology
Which main solute is used to measure kidney functions?
Creatinine
How could glucose cause an abnormal urinary constituet? What would be the name of the condition and its possible causes?
The name of the condition is glycosuria and it’s possible causes include Diabetes mellitus
How could proteins cause an abnormal urinary constituet? What would be the name of the condition and its possible causes?
The name of the condition is either proteinuria or albuminuria. It’s possible causes include non-pathologic examples are excessive physical exertion or pregnancy and pathological examples include glomerulonephritis, severe hypertension, Heart failure, often and initial sign of renal disease
How could ketone bodies cause an abnormal urinary constituet? What would be the name of the condition and its possible causes?
The name of the condition is ketonuria and causes include excessive formation of ketone bodies like with starvation and untreated diabetes mellitus
How could hemoglobin cause an abnormal urinary constituet? What would be the name of the condition and its possible causes?
The name of the condition is hemoglobinuria and it’s possible causes include various reasons such as transfusion reactions, hemolytic anemia, severe burns, etc.
How could bile pigments cause an abnormal urinary constitute? What would be the name of the condition and its possible causes?
The name of the condition is called bilirubinuria and it’s possible causes include liver disease, like hepatitis or cirrhosis, or obstruction of bile ducts from liver or gallbladder
How could erythrocytes cause an abnormal urinary constitute? What would be the name of the condition and its possible causes?
The name of the condition is called hematuria and it’s possible causes include bleeding urinary tract due to things like trauma, kidney stones, infection, or cancer
How could leukocytes cause an abnormal urinary constituet? What would be the name of the condition and its possible causes?
Aka pus and The name of the condition is called pyuria. It’s possible causes include UTI
Deficiencies and consequences in sodium can be caused by?
Hypernatremia: CNS dehydration
Hyponatremia: Side effects of mental confusion
Deficiencies and consequences in K can be caused by?
Hyperkalemia: skeletal muscle weakness, flaccid paralysis
Hypokalemia: cardiac arrhythmias, flattened T wave on ECG
Deficiencies and consequences in calcium can be caused by?
Hypercalcemia: cardiac arrhythmia and cardiac arrest, excess bone break down
Hypocalcemia: tingling fingers, tremors, skeletal muscle, cramping in the legs
Deficiencies and consequences in phosphate can be caused by?
Hyperphosphatemia: Hypoparathyroidism
Hypophosphatemia: bone issues
What is creatinine and how is it used diagnostically?
This is the best approximation of GFR. Filtered at the renal corpuscle. No reabsorption. A small amount of excretion.
This gives us the biggest indicator of filtration and letting us know if the kidneys are functioning properly.
Deficiencies and consequences in chloride can be caused by?
Hypochloremia: aldosterone deficiency
Deficiencies and consequences in magnesium can be caused by?
Hypomagnesemia: Trimmers, increased neuromuscular excitability, cardiac arrhythmias
What is the normal result of creatinine in men?
0.7 to 1.3
What is the only substance in the body that is solely filtered through the kidneys?
Trick question, the answer is none of them
How do we measure kidney function?
Creatinine clearance
What is the normal result of creatinine in women?
0.6 to 1.1
Why is it that women have a lower blood creatinine level than men?
Women often have a lower blood creatinine level than men because women often have less muscle mass than men and creatinine level varies based on a person’s size and muscle mass
How is the proximal convoluted tubule important for sodium transport?
Sodium is often found in the extracellular space and maintains our blood pressure. A lot of sodium absorption occurs in the PCT and it works as a co-transporter (glucose) or counter-transporter (H+)to reestablish the net absorption of sodium and water. “where sodium goes, water flows”
How is the ascending loop of Henle important for sodium transport?
It works as a co-transport using a sodium-K-two chloride cotransporters (NKCC). Reabsorption of sodium chloride occurs but NOT water. Na and Cl will be passively diffused while the K will be counter-transported.
Where do diuretics works?
The ascending loop of henle
How does the descending loop of Henle work for sodium transport?
It actually has no part in sodium transport because it is only permeable to water which flows due to the osmotic gradient set up by the ascending loop of Henlee and the vasa recta
How does the RAAS system function?
So we have the RAAS system and this is where we start to talk about aldosterone in the DCT. Collecting duct is where we start talking about ADH, so our RAAS system is activated, when we have low sodium, low blood volume, low blood pressure.
How does the RAAS system get stimulated?
The juxtaglomerular complex is going to sense this decrease in blood pressure. We’re gonna have the release of renin, at the same time the liver releases angiotensinogen. Renin cleaves that angiotensinogen to become angiotensin I, which will flow through the blood into the lungs, where ACE actually converts angiotensin I to angiotensin II. Angiotensin II stimulates the kidneys. And will stimulate the adrenal cortex to release aldosterone, which will go to the DCT and result in sodium and water reabsorption.
How do the distal convoluted tubule in the RAAS system work together?
Low sodium, blood pressure, blood volume
Renin secretion equals angiotensinogen which leads to angiotensinogen one and then angiotensinogen one is cleared into angiotensinogen too by Ace. Aldosterone secretion occurs by the adrenal glands in the DCT.
What will Angiotensin II also cause?
Diffuse vasoconstrcition to help increase blood pressure
What happens in the body in response to increased in blood pressure?
When we want to decrease blood pressure. So when someone is for example in heart failure or they’re just you know overly hydrated or well hydrated. Naturesis via atrial natriuretic peptide (ANP) Which I talked about cardiology the atria will sense distention and what’s called an ANP to actually work to decrease aldosterone secretion so less sodium and water reabsorption in an attempt to get the kidneys to get rid of sodium and water, because we want to decrease our plasma volume. This will result in afferent arterial dilation and efferent and efferent constriction which will increase those pressures in those hydrostatic pressures to increase our GFR and again try to get rid of more sodium try to get rid of more water to then decrease plasma volume.
How do the collecting ducks and sodium reabsorption work together?
Passive sodium ions diffuse with the sodium K ATPase pump. Aquaporins Reabsorb the water in their presence is influenced by vasopressin and anti-diuretic hormone (ADH). They are released by the posterior pituitary gland. Non-osmotic diaries by central diabetes insipidus (DI) or nephrogenic DI. Typical symptoms include polydipsia.
How does Non-osmotic diuretics by central diabetes insipidus (DI) or nephrogenic DI occur?
We have those glucose channels that work in the beginning and proximal proximal convoluted tubule, that are full so we have extra glucose in the lumen. We’re pumping sodium into the interstitial fluid but the water wants to stay with t large glucose molecules so despite the presence of aquaporons. There’s also another condition called diabetes insipidus or nephrogenic diabetes, we have these aquaprorons hat are simulated by ADH but in people with diabetes insipidus there’s either a failure of release of ADH or inability of the kidneys to respond so actually there’s no aquaporons here so it’s kind of the same thing that’s its called diabetes insipidus, but this really has to do with ADH, not even glucose. In regular diabetes there’s glucose molecules here that are stuck in the water, but in diabetes insipidus there’s no glucose molecules, no aquaporons.
How would ADH be regulated in a well hydrated person?
Image shows a very well-hydrated person. The presence of ADH really has to do with the osmolality and plasma volume. Somebody drank a lot of water. Osmolality of their body fluids decrease and dilute blood volume. Body fluid it’s dilute , because they have more water. So the Osmo receptors all over the body that sense its diluted, let’s drop the amount of ADH/vasopressin off, because we don’t want to have more aquaporons. We don’t want to reabsorb water. We want to pee more water out.
What regulates vasopressin secretion?
The posterior pituitary
How would ADH be regulated in a dehydrated person?
Dehydrated person. We want more aquaporons. We want to reabsorb water. We want to have ADH or vasopressin, because our plasma volume is low
How does the body handle calcium and phosphate?
Some free calcium is filtered but then reabsorbed in the PCT. Hormonal control of calcium reabsorption in the DCT and CD occurs when PTH is released in response to low plasma calcium. PTH also activates 1-hydroxylase Enzyme to activate vitamin D increases calcium absorption in the G.I. tract. When calcium drops our parathyroid gland secretes PTH to reabsorb calcium, which happens in the distal duct and activate vitamin D for increased calcium reabsorption.
How does the body handle K?
Majority is filtered in the glomerulus and then reabsorbed. It is heavily influenced by aldosterone. K is a co-transport. Increase in aldosterone secretion from the adrenal cortex going to collecting ducts will result in much more secretion of water/sodium reabsorption in exchange for ** K secretion. This is where K sparing diuretics work!!
How does the body handle urea?
100% is filtered but then absorbed and secreted via diffusion. It assists with a hypertonic medullary gradient. breakdown of amino acids it’s filtered 100% in the glomerulus and then secreted. In the medulla to form that major gradient, of getting deeper into the kidneys is 1200 mOsm and some is due to urea down there. About 15% of it actually excreted.
When would we expect to see K in the urine?
K is secreted from cortical collecting ducts and excreted in the urine in individuals with high K. In individuals with low plasma (dehydrated) will have high K levels. With sodium being reabsorbed, we can see high levels of K. We could have high levels of K due to dehydration, low plasma, bananas.
When aldosterone is present in the DCT, what happens?
increase sodium reabsorption and water. Potassium excretion.
When would PTH be high?
Vitamin D deficiency: ↓ Ca²⁺ absorption from gut and ↑ PTH to compensate
Chronic kidney disease (CKD): ↓ phosphate excretion → ↑ serum phosphate, ↓ 1-alpha hydroxylase activity → ↓ calcitriol (active Vit D), Leads to hypocalcemia → ↑ PTH
Malabsorption syndromes (e.g., celiac, bariatric surgery): ↓ calcium and vitamin D absorption
Hypocalcemia from other causes (e.g., pancreatitis, medications like loop diuretics)
When would we expect to see increased calcium excretion?
So the bones will work with the kidneys and PTH to help raise calcium levels.
**Hypercalcemia (Any Cause): **High serum calcium = more filtered load at the glomerulus → increased urinary calcium excretion. Vitamin D toxicity
**Loop Diuretic Use (e.g., Furosemide): **Inhibits Na⁺/K⁺/2Cl⁻ transporter in the thick ascending limb.. This disrupts the positive luminal charge, which normally drives calcium reabsorption → result: ↑ calcium excretion.
High Sodium Intake: Sodium and calcium reabsorption are linked, especially in the proximal tubule. High Na⁺ → less Ca²⁺ reabsorption → ↑ urinary calcium.
Renal Tubular Disorders
osteoclasts get chomped
When would we expect to see increased calcium reabsorption?
Elevated Parathyroid Hormone (PTH): PTH increases calcium reabsorption in the distal convoluted tubule., Also increases calcium release from bone and activates vitamin D → more calcium absorption in the gut., Classic in primary hyperparathyroidism or secondary hyperparathyroidism.
Increased Calcitriol (1,25-dihydroxyvitamin D): Increases intestinal calcium absorption and renal reabsorption. Seen in vitamin D supplementation or granulomatous diseases (like sarcoidosis or TB, which activate vitamin D via macrophages).
Volume Depletion / Hypovolemia: Body retains sodium and water → also increases passive proximal calcium reabsorption with sodium. Calcium follows sodium and water reabsorption in the proximal tubule.
Thiazide Diuretic Use: Thiazides increase calcium reabsorption in the distal tubule. Commonly used in patients with calcium kidney stones because they help reduce urinary calcium excretion.
** Hypocalcemia:** Triggers PTH secretion → ↑ renal calcium reabsorption.
What is the renal mechanism for managing H+?
Remember increased carbon dioxide means more H+ in therefore lower pH or acidity.
H+ increase to compensate for CO2, so we push the equation towards the right and therefore we decrease pH to cause more acidity.
Anything that binds to a hydrogen ion is known as a what?
A buffer
Carbon dioxide and bicarb are major extracellular buffers
Protein and phosphates are major intracellular buffers
Renal and respiratory systems work together to maintain what?
PH balance
The respiratory system worked by either hyper or hypoventilating
The kidneys altered bicarb concentrations via secretion or reabsorption
What does bicarb reabsorption look like?
The epithelial cells of the nephron have carbonic anhydrase. If someone needs to get rid of H+, the epithelial cells will take water and the carbon dioxide using carbonic anhydrase to develop carbonic acid which will secrete H+ and absorb the bicarb into the interstitial fluid and the blood so that bicarb can bounce around and be used as a buffer.
What does the formation of new bicarbonate via ammonium secretion look like?
We can also form carbonate in the kidneys via ammonia. Ammonia excretion occurs and we will transport glutamine. With the breakdown of glutamine we will have the formation of ammonia and bicarb. H+ ions are buffered by glutamine breakdown
What are the two compensatory mechanisms for excretion of H+ ions when the environment is acidic?
Compensatory mechanisms to be able to get rid of more and more H+ through ammonia and then through the binding of H+to phosphate in the kidneys
What does K buffering look like and how does it work?
The hydrogen ion shifts in and out of cells in the opposite direction of K to maintain cation balance. Protein and hemoglobin buffering happens too. Hyperkalemia for example. K transport with all this extracellular K floating around i.e. blood vessels right extracellular we’re kind of here in the blood vessels in the interstitial fluid we’ve got a lot of H+ so we ship that into the cell in the opposite direction of the K and just helps buffer for a little bit to help prevent it from damaging parts of the body. We can see people who are really acidotic they can become hyperkalemic because we’re putting all of these K+ back into their blood in attempt to shift those H+.
What does non-bicarbonate buffering a.k.a. a phosphate look like?
Before you know we talked about glutamine as a kind of non-bicarb system but also phosphate we also can can bind so what will happen is we will have H+. Bicarb created H+ will then go and bind you know to phosphate so we can pick up more H+ to get them and prepare them for excretion to buffer more. This happenes in the tubular lumen of the kidneys.
What are the different acid based disorders?
Respiratory
Acidosis= hypoventilation
Alkalosis= hyperventilation
Metabolic
Acidosis= hypoxia (increased lactic acid-can also get form sepsis), diabetic ketoacidosis, loss of HCO3 in diarrhea
Alkalosis= vomiting (loss of HCl)
What are the four buffer mechanisms we discussed?
glutamate, bicarb, phosphate, potassium
What is mitosis?
There are four stages in total (Plus interphase). Happens in somatic cells. Purpose is cell proliferation. Produces to diploid daughter cells. Chromosome number remains the same. Genetic variation doesn’t change. This is essentially cellular replication reproduction of cells with production of two diploid (46 chromosomes) daughter cells.
What things about mitosis and meiosis are the same?
Produce new cells
Similar basic steps
Start with a parent cell
What is meiosis?
Eight stages in total (plus Interphase). Happens in germ cells. Purpose is sexual reproduction. Produces four haploid (23 chromosomes) daughter cells. Chromosome number is halved in each daughter cell. Genetic variation increased
What is spermatogenesis?
Formation of male gamete (Sperm)
Gametes/ oocytes. We have sperm in the seminiferous tubules that goes through several miotic divisions to then form four haploid spermatids and then sperm cells with 23 chromosomes
Sperm isn’t made until puberty.
What are the seminiferous tubules and what about their anatomy contributes to spermatogenesis?
Seminiferous tubules consist of a thick stratified epithelium surrounding a central fluid-filled lumen containing four important types of cells: sustentocytes (Sertoli cells), spermatogenous cells, myoid cells, interstitial endocrine cells (Leydig cells).
What is the function of myoid cells?
Smooth muscle like cells surrounding seminiferous tubules that contract to squeeze sperm in testicular fluid through the tubules
Where and how does Spermatogenesis occur?
Occurs in the seminiferous tubules. Begins at puberty around 14 years of age. Adult males make about 90 million sperm daily. Females are born with all of there eggs.
How can sperm create an autoimmune disease?
Sperm doesn’t form until puberty, so it is absent during immune system development. So sperm is technically a foreign substance and therefore in instances where the proper physiologic processes don’t take place, a person could get an autoimmune disease. Sperm need to be kept seperate in the body to avoid being attacked by the immune system. The semniferous tubules have four very specialized type cells that help to do this.
What are the functions of Sertoli cells (Sustenocytes)?
Supporting cells and play role in sperm formation, form blood testes barrier so the immune system doesn’t attack it, nutrients, secretion of testicular fluid
What is the function of spermatogenic cells?
Cells that are surrounded by sustenocytes and give rise to sperm
What is the function of interstitial endocrine cells (Leydig cells)?
Produce testosterone
What are the phases of spermatogenesis and what occurs in each?
**Mitosis **of spermatogonia (Stem cell) Forms to spermatocytes
**Meiosis: **spermatocyte form secondary spermatocytes, which form spermatids
Spermiogenesis: spermatids become sperm
What is the process of spermatogenesis?
Spermatogonia, so stem cells that are indirect contact divide continuously by mitosis and during that time they differentiate into type A and B daughter cells. Type B daughter cells undergo meiosis to then become secondary spermatocytes undergo meiosis. Secondary spermatocytes rapidly undergo to become two duirng meotic division. Then we have spermatoza which are round cells with very large nuclei they dont do anything, theyre immobile. They contain the number of chromosomes. Things occur as the sperm continue to flow through testes and undergo further differentiation like elongate, they lose cytoplasm, form their tail, form typical kind of sperm structure that we’re used to with like a headpiece and a tail.
How long does the process of spermatogenesis take?
Spermatogenesis takes 64 to 72 days if conditions are hospitable.
How do the sperm function after spermatogenesis?
Sperm are unable to swim, but pressure of testicular fluid pushes and immotile sperm into the epididymis where they gain motility and fertilizing power
What is the physiology of an erection?
The parasympathetic innovation causes local release of nitric oxid. NO causes arterial dilation and relaxation of the vascular smooth muscle this is all parasympathetic. The corpus cavernosa, the structure of the top of the penis just above the urethra expands and fills with blood. Here we start to see issues with erectile dysfunction. The corpus spongiosum keeps the urethra open
What are some typical reasons for ED?
Multiple reasons it’s about 50% of men over the age of 40 have ED. Part of it has to do with some of the parasympathetic nerves are releasing little to no NO. RF: psychological, alcohol, drugs, blood pressure meds like beta blocker, atherosclerosis, so blood vessels in the penis where individuals are unable to get an engorgement of the penis, so they have that crisis in the nervous system. History of a stroke, neuropathy
Ejaculation is mediated by spinal reflexes in what structures?
Ductus deference, prostate, and seminal glands contract and empty contents into the prostatic urethra
Semen and urethra trigger spinal reflections through somatic neurons and affect the Bulbosponogiosus muscle, which undergoes a rapid series of contractions that cause an explosion of sperm at 500 cm/s. This is close to about 11 mph (purposefully to help with fertilization)
Ejaculation is followed by?
Resolution is the period of muscular and psychological relaxation where the arteries and arterioles are constricted by signals from sympathetic nerves reducing blood flow to the penis.
What is the latent (refractory) period of ejaculation?
The time during which man is unable to achieve another orgasm. This can last minutes to hours. The latent lengthens with age. Some people with ED concerns can get an erection, but cannot ejaculate.
How many people does infertility affect?
Infertility affects roughly one and seven couples in America
What is the most common cause of infertility?
Infertility is often caused by problems with sperm quality or quantity. Gradual decline and male fertility have been occurring in the past 50 years
What sperm characteristic has the most significant impact on miscarriages?
sperm quality or quantity
What is one of the biggest beliefs about infertility?
Some believe the main culprit is foreign molecules ingested such as environmental toxins, phthalates (Oily solvents from plastics), Pesticides, herbicides, etc.
Infertility can also be caused by what other factors?
Estrogen-like compounds block the action of male sex hormones
AntibioticsSuch as tetracycline may suppress sperm formation
Radiation, lead, marijuana, and excessive alcohol can cause abnormal sperm to be produced (To head, multi-tailed)
Defects and calcium channels, hormonal imbalance, and oxidative stress
Thermal related events, such as sperm are overuse of hot tubs may inhibit sperm maturation
What hormones are involved in the control of male reproduction?
Gonadotropin-releasing hormone (GnRH)
Follicle stimulating hormone (FSH)
Luteinizing hormone (LH)
What is the main function of GnRH?
released by the hypothalamus is released in pulsatile way every 90 mins. Which stimulates the anterior pituitary to secrete FSH and LH which will go on to make Sertoli cells and leydig cells. The leydig cells will then go on to make testosterone, aid in sperm formation, and help with some of the secondary sex characteristics. FSH goes to the sertoli which will stimulate spermatogenesis but also have negative inhibitory effects on the anterior pituitary (negative feedback mechanisms). Mostly used during puberty, but also some throughout the life cycle
Do men have GnRH all throughout the lifespan?
Yes, but it spikes during puberty to develop secondary sex characteristics
What are some of the other actions of testosterone?
Testosterone is synthesized from cholesterol and does the following functions:
Maintains male secondary sex characteristics and accessory reproductive organs and libido
Converted to die Hydro testosterone (DHT) In the prostate and estradiol in some brain neurons
Prompts spermatogenesis
Has multiple anabolic affects throughout the body
Deficiency leads to atrophy of accessory organs, semen volume declines, an erection or ejaculation are impaired, treatment is testosterone replacement
What are secondary sex characteristics?
These are the features introduced in non-reproductive organs by the male sex hormones. Mainly testosterone
What are the male secondary sex characteristics?
Appearance of pubic, axillary, and facial hair
Enhanced growth of hair on chest or other areas
Larynx enlargement causes deepening of voice
Skin thickens and becomes oily
Bones grow and increase intensity
Skeletal muscle muscles increase in size and mass
Boost basil metabolic rate
This is the basis of sex drive or libido in males
