Final Exam Flashcards
Set 1: Kidney Structure & Function:
Renal Lecture 1
That are the roles of the kidneys?
Balance salt & water, regulate ions, maintain pH, excrete wastes, produce EPO, produce renin, activate Vitamin D.
What do the kidneys filter per day?
200L/day.
What are the parts of the urinary system and their functions?
Kidneys: Make urine.
Ureters: Transport urine to bladder.
Bladder: Stores urine.
Urethra: Excretes urine.
What is the size and location of the kidneys?
Bean-shaped, retroperitoneal (T12-L3), size ~150g, 12 x 6 x 3 cm.
What protects the kidneys?
Rib cage (right kidney lower due to liver).
That is the shape of the kidneys, and what is the protective structure?
Concave (hilum to renal sinus), with supportive layers:
Renal capsule: Barrier to damage.
Perirenal fat: Cushions, stabilizes.
Renal fascia: Anchors kidney/adrenal.
Set 2: Kidney Anatomy & Circulation
What is the internal anatomy of the kidneys?
Cortex: Filtration & urine formation.
Medulla: Striped due to pyramids & columns.
Pelvis: Funnels urine to ureter via calices.
Smooth muscle moves urine by peristalsis.
What is the circulatory pathway through the kidney?
Renal Artery → Segmental Artery → Interlobar Artery → Arcuate Artery → Cortical Radiate Artery → Afferent Arteriole → Efferent Arteriole → Peritubular Capillaries/Vasa Recta → Cortical Radiate Vein → Arcuate Vein → Interlobar Vein → Renal Vein.
How much blood do the renal arteries supply to the kidneys?
~1/4 cardiac output (~1.2 L/min).
What is the role of the Renal Plexus?
The renal plexus, a sympathetic nerve supply, regulates blood flow and the filtration rate by controlling blood vessel diameter.
Set 3: Kidney Filtration Process
What happens during the blood filtration process in the kidneys?
Blood enters via the renal artery, gets filtered in the glomerulus, and passes into the Bowman’s capsule.
What are the functions of the different parts of the nephron?
PCT: Reabsorbs nutrients.
Loop of Henle: Water reabsorption (descending) and ion reabsorption (ascending).
DCT: Reabsorption & secretion.
Collecting Duct: Concentrates urine.
What is the function of the Juxtamedullary nephron?
It has a long Loop of Henle for efficient water reabsorption, especially in times of dehydration.
What is the filtration function of the Glomerulus?
The glomerulus filters blood into Bowman’s capsule, removing waste products.
Set 4: Juxtaglomerular Complex & Blood Pressure Regulation
Where is the Juxtaglomerular Complex (JGC) located?
Between the early DCT and afferent/efferent arterioles.
What are the components of the JGC?
Granular (JG) cells, which secrete renin, and Macula Densa cells, which monitor filtrate and adjust GFR.
How does the JGC regulate blood pressure and filtration?
The JGC releases renin, which helps control blood pressure and GFR by influencing the RAAS system.
Set 5: Urethra & Micturition
What are the differences between male and female urethras?
Males: Longer (~20 cm), internal sphincter (smooth muscle, involuntary), external sphincter (skeletal muscle, voluntary).
Females: Shorter (~4 cm), internal sphincter (involuntary), external sphincter (voluntary).
What is the function of the trigone in the bladder?
The trigone is a triangle formed by the openings of the ureters and urethra; it is clinically important for UTIs.
What must happen for micturition to occur?
The external urethral sphincter must open, the pontine micturition center must be activated, the internal urethral sphincter must open, and the detrusor muscle must contract.
What is the capacity of the bladder?
Normal bladder capacity is 500 mL (can hold up to 1000 mL).
Set 6: Kidney Pathologies & Disorders
What is pyelonephritis?
A kidney infection usually caused by a UTI spreading to the kidneys, leading to pain and potential damage.
What is the treatment for kidney stones?
Kidney stones can block urine flow and are typically treated by lithotripsy.
What would happen if albumin levels in the blood were insufficient?
A drop in blood osmotic pressure would occur, leading to a rise in filtrate production.
Renal Lecture 2
Glomerular Filtration Overview;
What is the process of glomerular filtration?
Passive and nonselective, driven by capillary pressure, efficient due to high permeability and pressure difference, filters 180 L/day.
What is the Filtration Membrane and its components?
Fenestrated capillary endothelium, basement membrane, and visceral membrane (podocyte foot processes).
What does the filtration membrane allow to pass?
Small molecules and water pass easily, while proteins and blood cells are blocked. Larger proteins indicate membrane damage.
Pressure and Filtration:
What is the role of hydrostatic and osmotic pressure in glomerular filtration?
HPg (glomerular blood hydrostatic pressure) pushes fluid out, OPg (blood colloid osmotic pressure) pulls fluid back in, and HPc (capsular hydrostatic pressure) pushes fluid into blood. The net filtration pressure (NFP) determines filtrate formation.
Glomerular Filtration Rate (GFR):
What is the Glomerular Filtration Rate (GFR)?
The rate at which filtrate is formed (~125 mL/min), influenced by filtration surface area, membrane permeability, and NFP.
What affects the GFR?
Large surface area, membrane permeability, and net filtration pressure. A drop in BP or dehydration can decrease GFR.
Regulation of GFR:
What are the three mechanisms regulating GFR?
Renal Autoregulation (intrinsic): Adjusts nephron blood flow via myogenic mechanism and tubuloglomerular feedback.
Neural Controls (extrinsic): SNS redirects blood to vital organs during stress, affects afferent arterioles.
Renin-Angiotensin System (extrinsic): Activated by low BP or sodium, causes vasoconstriction and increased GFR.
What is the myogenic mechanism of GFR regulation?
It responds to changes in blood pressure. High BP causes afferent arteriole constriction to reduce blood flow; low BP causes relaxation to increase blood flow.
What is the tubuloglomerular feedback mechanism?
Macula densa cells monitor NaCl levels; high NaCl causes vasoconstriction, low NaCl causes vasodilation.
Hormonal and Neural Control of GFR:
How does the Renin-Angiotensin System affect GFR?
Renin release leads to angiotensin II, a potent vasoconstrictor, increasing blood pressure and filtration rate.
How do neural controls influence GFR?
Under stress, sympathetic activation causes vasoconstriction, decreasing GFR and redirecting blood to vital organs.
Tubular Reabsorption and Secretion:
Why is tubular reabsorption important?
It ensures that most filtered blood volume is reabsorbed (around 45 minutes for total blood volume), preventing wasteful excretion.
What are the key principles of tubular reabsorption?
Organic nutrients like glucose are 100% reabsorbed. Reabsorption can be active (e.g., Na+) or passive (e.g., water via aquaporins), and regulated by hormones.
What substances are actively vs. passively reabsorbed?
Active reabsorption: Sodium, glucose, amino acids. Passive reabsorption: Water, lipid-soluble substances, urea.
What substances are not reabsorbed, and why?
Creatinine (waste product), urea (partially reabsorbed), and drugs/medications (excreted).
Pressure and Filtration in the Glomerulus:
Why is glomerular blood pressure so high?
The glomerular capillaries are drained by a high-resistance efferent arteriole, maintaining high pressure across the capillary bed for filtration.
Renal Lecture 3
Tubuloglomerular Feedback Mechanism
What are the correct statements in the tubuloglomerular feedback mechanism?
A. Granular (JG) cells monitor the amount of stretch of the afferent arteriole.
B. Increased stretch prompts vasoconstriction of the afferent arteriole.
C. Macula densa cells release ATP in response to fast flowing filtrate.
D. A rise in glomerular blood pressure prompts vasoconstriction of the efferent arteriole (incorrect).
Renal Tubular Transport
Describe the transcellular and paracellular routes of renal reabsorption.
Transcellular Route: Transport across apical and basolateral membranes, diffusion through cytosol, movement into peritubular capillary via interstitial fluid (similar to intestinal absorption).
Paracellular Route: Movement through leaky tight junctions (mainly in PCT), movement into capillary (mainly for H2O and some ions like Ca++, Mg++, K+, Na+).
Passive and Active Reabsorption
What are the mechanisms of passive reabsorption in the kidneys?
Diffusion, facilitated diffusion, osmosis.
Moves along electrochemical gradients, no ATP needed.
Na+ reabsorption pulls Cl-, water follows Na+ via aquaporins.
Kidney Regions and Functions
How do the regions of the kidney function in reabsorption and secretion?
Cortex: 65% reabsorption (H2O, Na+, glucose, amino acids). Na+ (by aldosterone), Ca2+ (by PTH).
Outer Medulla: Secretes H+, NH4+, K+ (by aldosterone), reabsorbs water (by ADH).
Inner Medulla: Secretes K+ (by aldosterone), regulates blood pH.
Tubular Secretion and Functions
What are the functions of tubular secretion?
Dispose of unwanted substances (e.g., drugs and metabolites bound to plasma proteins).
Eliminate substances with passive reabsorption (e.g., urea, uric acid).
Excess K+ ion disposal, maintain blood pH (e.g., secreting excess H+).
Secretion occurs mainly in the PCT, and also in the late DCT and early collecting ducts.
Countercurrent Mechanism and Osmolarity
What is the countercurrent mechanism in the kidney?
Descending limb: Permeable to water, so water moves out by osmosis.
Ascending limb: Reabsorbs Na+ and Cl-, impermeable to water.
Osmolarity can reach 1200 mOsm in juxtamedullary nephrons.
Renal Clearance and Kidney Function
What is renal clearance, and how is it measured?
Renal clearance is the volume of plasma from which kidneys clear a substance per minute.
Formula: C = (U × V) / P, where U is concentration in urine, V is urine flow rate, and P is concentration in plasma.
Inulin is used to measure GFR (glomerular filtration rate).
Urine Composition and Abnormalities:
Descending limb: Permeable to water, so water moves out by osmosis.
Ascending limb: Reabsorbs Na+ and Cl-, impermeable to water.
Osmolarity can reach 1200 mOsm in juxtamedullary nephrons.
What are the normal and abnormal components of urine?
Normal: 95% water, 5% solutes (urea, Na+, K+, PO43−, SO42−, creatinine, uric acid).
Abnormal: Glucose (diabetes), proteins (kidney issues), ketones (starvation/diabetes), blood (hematuria), leukocytes (UTI).
Electrolyte Imbalances
What are the symptoms of electrolyte imbalances?
Hypernatremia (excess sodium): Confusion, muscle twitching, coma.
Hyponatremia (low sodium): Brain swelling, confusion, shock.
Hyperkalemia (high potassium): Cardiac arrhythmias, muscle weakness.
Hypokalemia (low potassium): Muscle weakness, arrhythmias, confusion.
Hormonal Regulation and Feedback Mechanisms
How does the RAAS system regulate blood pressure and fluid balance?
RAAS System: Renin → Angiotensin I → Angiotensin II → Vasoconstriction & aldosterone release, which increases Na+ and H2O reabsorption, raising blood volume and pressure.
Renal Lecture 4
Topic 1: Renal Function & Clearance
If one says that the renal clearance of a substance is 140 (assume normal GFR), what does this mean?
he substance is freely filtered and some is also secreted.
What does alcohol do to act as a diuretic?
Inhibits the release of ADH.
Topic 2: Micturition & Incontinence
What are the three requirements for micturition?
Detrusor muscle must contract, internal urethral sphincter must open, external urethral sphincter must open.
What triggers the micturition reflex at 200 ml of urine?
Stretch receptors send afferent signals to the sacral spinal cord, efferent signals via parasympathetic nerves cause detrusor contraction, and the internal sphincter relaxes.
What is stress incontinence?
Urine leakage from pressure (e.g., coughing).
Topic 3: Renal Failure & Dialysis
What is renal failure and what are its symptoms?
Renal failure is reduced or stopped filtrate formation due to damaged nephrons, with symptoms like nitrogen buildup, acidity, and edema.
What is Peritoneal Dialysis and how is it done?
It uses the peritoneal membrane for filtration, done at home/work with no hospital visits, dialysate infused to remove waste from the blood.
Topic 4: Fluid Compartments & Electrolytes
What is the primary difference between intracellular and extracellular fluid compartments?
ICF makes up about 60% of body fluid, while ECF makes up 40%. ECF is divided into plasma and interstitial fluid.
How do electrolytes differ from non-electrolytes?
Electrolytes dissociate into ions, creating more particles in solution, and are essential for osmotic balance.
Topic 5: Hormonal Regulation of Fluid Balance
How does ADH affect water reabsorption?
DH prompts the kidney to reabsorb and conserve water, reducing urine output.
What happens when plasma osmolality increases?
Thirst increases, leading to water intake, and ADH secretion stimulates water reabsorption.
Topic 6: Sodium & Aldosterone
How does aldosterone regulate sodium balance?
Aldosterone promotes sodium reabsorption in the DCT and collecting ducts, essential for sodium balance.
What triggers aldosterone release?
Renin-Angiotensin system and high potassium or low sodium levels.
Topic 7: Water Balance & Disorders
What is dehydration, and what are its consequences?
Dehydration is water loss or fluid + salt loss, leading to increased ECF osmotic pressure and cell shrinkage.
What is hypotonic hydration?
It dilutes sodium in the ECF, causing water to move into cells, resulting in cell swelling.
Topic 8: Thirst Mechanism & Water Regulation
How does the body respond to low plasma volume?
Low plasma volume triggers thirst via baroreceptors and activates renin-angiotensin to increase water intake.
What is the role of ADH in the thirst mechanism?
DH regulates water reabsorption; it increases in response to high plasma osmolality and decreases with low plasma volume.
Topic 9: Disorders of Water & Electrolyte Balance
What is hyperkalemia, and how is it affected by damaged kidneys?
Hyperkalemia occurs when kidneys cannot excrete potassium, leading to high levels of potassium in the blood.
What is the effect of aldosterone on potassium?
Aldosterone promotes the excretion of potassium, reducing its levels in the body.
Renal Lecture 5
Electrolyte and Fluid Balance
Which of the following statements is FALSE?
e. Bicarbonate ion is the major anion found in interstitial fluid.
Explanation: The major anion in interstitial fluid is chloride (Cl⁻), not bicarbonate.
Which of the following factors will trigger increased release of ADH?
e. B and D
Explanation: A decrease in ECF volume (B) and an increase in ECF osmolarity (D) both trigger the release of ADH to conserve water.
Sodium’s role and its balance:
Aldosterone increases sodium reabsorption to raise blood pressure.
ADH helps maintain sodium balance through water reabsorption.
ANP reduces sodium reabsorption to lower blood pressure.
Potassium, Calcium, and Phosphate Balance
Potassium Balance - What is the impact of high ECF K+?
Explanation: High potassium levels in the extracellular fluid (ECF) are toxic, especially in cardiac muscle. The kidneys regulate potassium by reabsorbing it in the proximal convoluted tubule (PCT) and nephron loop, while excess K+ is secreted in the distal convoluted tubule (DCT).
Calcium and Phosphate Balance
Hormones:
PTH (Parathyroid hormone) increases blood calcium by stimulating osteoclasts in the bone, promoting reabsorption in kidneys, and activating Vitamin D.
Calcitonin decreases blood calcium levels.
Acid-Base Balance Mechanisms
Acid-Base Balance Mechanisms include:
Buffer Systems: Bicarbonate, protein, and hemoglobin buffers neutralize pH changes.
Respiratory Mechanism: CO₂ regulation helps control blood pH by adjusting ventilation.
Kidney Mechanism: Excretes H⁺ and reabsorbs HCO₃⁻ to balance pH.
Strong vs. Weak Acids
Explanation: Strong acids fully dissociate, increasing H⁺ concentration, while weak acids only partially dissociate, causing a smaller change in pH.
Phosphate Buffer System
HPO₄²⁻ is the weak base in the phosphate buffer system. Type A intercalated cells in the kidneys secrete H⁺ and generate new bicarbonate (HCO₃⁻).
Renal Function and Regulation
Bicarbonate Reabsorption in the kidneys
Explanation: Bicarbonate is reabsorbed indirectly via bicarbonate formed in tubule cells. Na⁺ follows bicarbonate into the blood.
What happens during respiratory acidosis?
Explanation: Respiratory acidosis occurs during hypoventilation, allowing CO₂ to accumulate in the lungs, which decreases pH and increases PCO₂.
Clinical Scenarios and Acid-Base Disorders
Problem: pH = 7.6, P(CO2) = 24 mm Hg, HCO3- = 23 mEq/L
A:
Diagnosis: Respiratory Alkalosis with compensation.
Explanation: A pH higher than normal indicates alkalosis, and low CO₂ is compensating for this.
What is the diagnosis for: pH = 7.25, P(CO2) = 46 mm Hg, HCO3- = 33 mEq/L?
Diagnosis: Mixed Acid-Base Disorder: Metabolic alkalosis with respiratory compensation.
Explanation: The high HCO3- indicates metabolic alkalosis, while the high PCO₂ suggests respiratory compensation.
Endocrine and Hormonal Regulation
Aldosterone’s direct actions
Aldosterone increases sodium reabsorption, indirectly increasing water retention, which raises blood volume and pressure. It also promotes potassium excretion.
Metabolic and Respiratory Acidosis/Alkalosis
What factors affect respiratory acidosis?
Explanation: Respiratory acidosis is caused by hypoventilation, leading to CO₂ buildup, which increases acidity in the blood.
Reproductive System Lecture 1
Phase 1: Creating Active Recall Questions
What are the primary functions of the male reproductive system?
Produce and deliver sperm for fertilization.
Produce male hormones (testosterone) for secondary sexual characteristics and reproductive functions.
What are the primary functions of the female reproductive system?
Produce eggs (ova) for fertilization.
Provide a site for fertilization and fetal development.
Produce female hormones (estrogen, progesterone) for menstrual cycles, pregnancy, and secondary sexual characteristics.
What should you understand before studying the anatomy and physiology of the reproductive systems?
Basic human anatomy (organs involved in reproductive processes).
Endocrine system (hormonal regulation and feedback loops).
Cell division and gametogenesis (spermatogenesis in males and oogenesis in females).
Genetics (chromosomes and inheritance).
What are the differences between cyclical and steady reproductive systems?
Female System (Cyclical): Undergoes monthly cycles (menstrual cycle), influenced by estrogen and progesterone.
Male System (Steady): Continuous sperm production, testosterone levels relatively constant, no cyclical fluctuations.
What are the key differences allowing the female system to be cyclical and the male system to be steady?
Female Cyclical System: Hormonal fluctuations regulate ovulation, menstruation, and uterine preparation for pregnancy.
Male Steady System: Continuous sperm production, constant secretion of testosterone, not tied to a cycle.
What are the key anatomical features of the male reproductive system?
Testes: Located in the scrotum, external to the abdominopelvic cavity, produce sperm and testosterone. Temperature regulation (testes are 30°C cooler than body temperature) is crucial for spermatogenesis.
Ovaries vs. Testes: Ovaries are inside the abdominopelvic cavity, while testes are external for temperature regulation.
What is the role of the tunics in the testes?
Tunica Vaginalis: Outer, 2-layered membrane.
Tunica Albuginea: Fibrous capsule dividing the testis into lobules with seminiferous tubules for sperm production.
How do the Dartos and Cremaster muscles contribute to temperature regulation of the testes?
Dartos Muscle: Contracts in cold to wrinkle and pull testes closer, relaxes in heat to loosen.
Cremaster Muscle: Pulls testes closer in cold, relaxes in heat for cooling.
What is the process of testicular descent?
Testicular Descent: The testes descend from the abdominopelvic cavity into the scrotum before birth.
Seminiferous Tubules: Arranged to avoid overlap for proper sperm production.
What is the pathway of sperm from production to ejaculation?
Sperm is produced in seminiferous tubules, travels through the tubulus rectus, rete testes, efferent ductules, epididymis (matures), ductus deferens, and urethra.
What are the roles of Leydig and Sertoli cells in the testes?
Leydig Cells: Produce testosterone, located between seminiferous tubules, ‘interstitial.
Sertoli Cells: Support spermatogenesis, located inside seminiferous tubules.
What is the blood supply to the testes?
Testicular Arteries: Branch from the abdominal aorta to supply blood to the testes.
Testicular Veins: Form the pampiniform plexus, a network of veins around the testicular artery.
What is the role of the pampiniform plexus?
Cools the blood in the testicular artery before it reaches the testes to maintain a lower temperature for sperm production.
What is the sperm pathway from the epididymis to the exterior?
Epididymis: Sperm mature over 20 days and gain motility.
During Ejaculation: Smooth muscle contracts, propelling sperm into the vas deferens.
Sperm Not Ejaculated: Stored for 2-3 months in the epididymis and recycled if not ejaculated.
What is the function and pathway of the ductus deferens?
Length: ~45 cm long.
Pathway: Travels from the epididymis to the ejaculatory duct, passing through the prostate gland into the urethra.
What is a vasectomy?
A method of birth control where the vas deferens is cut or blocked to prevent sperm from reaching the urethra.
What is the structure and function of the urethra?
Function: Serves both urinary and reproductive functions.
Regions: Prostatic urethra, intermediate part, and spongy urethra.
What are the seminal vesicles and their role in semen?
Location: Behind the bladder.
Function: Contribute 70% of semen, providing fructose for sperm energy and enzymes for motility.
What is the prostate gland, and what does it contribute to semen?
Location: Chestnut-shaped, encircles the urethra beneath the bladder.
Function: Produces a milky secretion (1/3 of semen), containing enzymes and PSA to activate sperm.
What are the bulbourethral glands, and what is their role?
Location: Below the prostate.
Function: Secrete clear mucus to clean urine traces and provide lubrication before ejaculation.
What are the key structures of the penis?
Function: Delivers sperm into the female reproductive tract.
Parts: Root, shaft, glans penis (enlarged tip), foreskin (prepuce, removed in circumcision).
What is the internal structure of the penis?
Spongy Urethra: Part of the urethra in the penis.
3 Corpora:
2 Corpora Cavernosa: Paired dorsal tissues.
1 Corpus Spongiosum: Midventral tissue, forms glans and bulb.
What is the composition of semen?
Functions: Transport medium for sperm, provides nutrients (fructose, citrate), chemicals (PGs, ATP, antibiotics) to protect and activate sperm.
pH: 7.2-7.6, neutralizes vaginal acidity.
Volume: 2-5 ml per ejaculation.
Sperm Concentration: 50-100 million/ml.
What is the difference between Sertoli and Leydig cells?
Sertoli Cells: Support spermatogenesis inside seminiferous tubules.
Leydig Cells: Located between seminiferous tubules, produce testosterone.
What are steroid hormones, and how are they related to testosterone?
Steroid Hormones: Derived from cholesterol, lipid-soluble, regulate gene expression.
Testosterone Synthesis: Produced by Leydig cells.
What are the actions of testosterone?
Gonadal: Growth/maturation of gonads and accessory organs, essential for spermatogenesis.
Somatic: Growth spurts, vocal cord growth, sweat secretion, hair growth (face, chest, groin).
Metabolic: Anabolic effects like hematopoiesis and BMR.
CNS: Affects libido and aggression.
How does steroid hormone action work?
Diffusion: Steroid hormone diffuses through plasma membrane.
Binding: Binds to intracellular receptor.
Nuclear Entry: Receptor-hormone complex enters the nucleus and binds to DNA.
Transcription: Initiates transcription and protein synthesis.
How are gonadotropins involved in steroidogenesis?
FSH: Stimulates Sertoli cells for spermatogenesis, requires testosterone.
LH: Stimulates Leydig cells to secrete testosterone.
GnRH: Stimulates the release of FSH and LH.
What is the role of Inhibin in regulating testosterone production?
Inhibin is released by Sertoli cells and inhibits FSH secretion, helping balance sperm production.
Male Reproductive System
Testes and Spermatogenesis
Reproductive System Lecture 2
What will occur as a result of non-descent of the testes?
Viable sperm will not be produced.
What are the main steps in spermatogenesis?
Spermatogonium (diploid) → Primary spermatocyte → Secondary spermatocyte → Spermatid → Spermatozoan.
What is the function of Sertoli cells?
Nourish developing spermatozoa.
Secrete fluid into seminiferous tubule lumen.
Digest cytoplasm discarded by spermatozoa.
Bind FSH and testosterone.
Produce inhibin.
What is the function of the blood-testis barrier?
Prevents immune response against developing sperm by isolating them from the blood supply.
What is the function of Leydig cells?
Located between seminiferous tubules.
Have receptors for LH and secrete testosterone to support spermatogenesis and accessory organs.
Sperm Maturation and Transport
What are the functions of the epididymis?
Sperm spend ~20 days here.
Undergo further maturation, including membrane and enzyme changes for:
Sustained motility.
Ability to bind to an egg.
What is the function of the bulbourethral glands?
Secrete thick, clear mucus to neutralize traces of acidic urine in the urethra.
What are the contributions of the seminal vesicles and prostate gland to semen?
Seminal vesicles: Secrete viscous, yellow fluid rich in fructose (energy for sperm) and prostaglandins (help sperm movement and viability).
Prostate gland: Secretes thin, milky fluid to neutralize the acidity of the male urethra and female vagina.
Which hormones regulate male reproductive function?
GnRH (from hypothalamus) stimulates FSH and LH release from the anterior pituitary.
FSH stimulates Sertoli cells to support spermatogenesis.
LH stimulates Leydig cells to produce testosterone.
Testosterone supports sperm development and male secondary sexual characteristics.
Inhibin (from Sertoli cells) inhibits FSH release.
Female Reproductive System
Ovaries and Oogenesis
What are the primary functions of the female reproductive system?
Produce gametes and hormones.
Prepare to nurture a developing embryo.
Describe the gross and microscopic anatomy of the ovaries.
External covering: Germinal epithelium and tunica albuginea.
Ovarian cortex: Contains follicles at different stages of development.
Ovarian medulla: Contains blood vessels and connective tissue.
What are the key hormones involved in female reproductive function?
GnRH: Stimulates FSH and LH release.
FSH: Promotes follicle development.
LH: Triggers ovulation and corpus luteum formation.
Estrogen & progesterone: Regulate menstrual cycle and pregnancy support.
Oviducts (Uterine/Fallopian Tubes)
What are the structures of the uterine tubes and their functions?
Fimbriae: Direct oocyte into the ampulla.
Ampulla: Common site of fertilization.
Isthmus: Narrow portion leading to the uterus.
How does the structure of the oviduct assist in oocyte movement?
Ciliated epithelium: Moves the oocyte toward the uterus.
Smooth muscle contractions: Aid in transport.
Uterus and Cervix
What are the three layers of the uterine wall?
Perimetrium: Outer connective tissue layer.
Myometrium: Thick smooth muscle layer for contractions.
Endometrium: Inner mucosal layer with two sublayers:
Stratum functionalis: Shed during menstruation.
Stratum basalis: Regenerates functionalis layer.
What is the function of the cervix?
Produces mucus that blocks bacteria.
Becomes less viscous at midcycle to facilitate sperm entry.
Vagina and External Genitalia
Describe the structure and function of the vagina.
Muscular tube (8-10 cm long).
Lined with stratified squamous epithelium (resistant to friction).
No glands; lubricated by cervical secretions.
Acidic pH to deter infections.
What are the major components of the external genitalia (vulva)?
Mons pubis: Fatty tissue covering the pubic symphysis.
Labia majora: Outer, hair-covered folds (homologous to the scrotum).
Labia minora: Inner, hair-free folds.
Clitoris: Erectile tissue (homologous to the penis).
Vestibule: Contains the openings of the urethra, vagina, and greater vestibular glands.
Short Answer Questions
What happens during spermiogenesis?
Spermatids undergo nuclear and cytoplasmic reorganization to form spermatozoa, developing a flagellum for motility.
Why does the vaginal epithelium store glycogen?
Glycogen is metabolized by resident bacteria to lactic acid, creating an acidic environment that protects against infections.
What is the function of the corpus luteum?
Forms from the ovulated follicle and secretes progesterone to maintain pregnancy.
What is the role of the broad ligament in female reproductive anatomy?
Supports the uterus, ovaries, and oviducts within the pelvic cavity.
Why are the uterine arteries and spiral arteries important in pregnancy?
They supply the endometrium with nutrients and oxygen to support embryo implantation and fetal development.
Reproductive System Lecture 3
Ovarian Anatomy and Function
What are the primary functions of the ovaries?
(i) Production of female gametes (oocytes).(ii) Secretion of reproductive hormones (estrogen, progesterone, inhibin, relaxin).
Oogenesis and Follicular Development
What are the two main structures within the ovary?
(i) Ovarian cortex - Contains ovarian follicles.(ii) Ovarian medulla - Contains blood vessels, lymphatics, and nerves.
What are ovarian follicles, and how do they develop?
Ovarian follicles consist of an oocyte surrounded by follicular cells. They progress through the following stages: primordial, primary, secondary, antral (tertiary), preovulatory (Graafian), and corpus luteum or corpus albicans (if no fertilization occurs).
When does oogenesis begin and end?
It begins during fetal development and is completed only upon fertilization of the secondary oocyte.
What are the key differences between primary and secondary oocytes?
Primary oocytes are arrested in prophase I of meiosis until puberty.
Secondary oocytes are arrested in metaphase II and only complete meiosis if fertilization occurs.
How does follicular development proceed?
Primordial follicle → Single layer of squamous cells surrounding oocyte.
Primary follicle → Granulosa cells proliferate, zona pellucida forms.
Secondary follicle → Theca layers form, antrum begins developing.
Antral follicle → Large antrum forms, granulosa and theca cells secrete estrogen.
Preovulatory (Graafian) follicle → Dominant follicle ready for ovulation.
Hormonal Regulation of the Ovarian Cycle
How do estrogen and progesterone influence the menstrual cycle?
Estrogen: Stimulates follicular development, endometrial proliferation, and secondary sexual characteristics.
Progesterone: Prepares the endometrium for implantation and maintains pregnancy.
What role does GnRH play in female reproduction?
Gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the anterior pituitary to release FSH and LH.
How do FSH and LH regulate the ovarian cycle?
FSH stimulates follicular growth and estrogen production by granulosa cells.
LH triggers ovulation and maintains the corpus luteum.
Ovulation and Luteal Phase
What triggers ovulation?
A surge in LH causes the dominant follicle to release the secondary oocyte into the fallopian tube.
What happens to the follicle after ovulation?
It transforms into the corpus luteum, which secretes progesterone to support potential pregnancy.
What maintains the corpus luteum if pregnancy occurs?
Human chorionic gonadotropin (hCG), secreted by the early embryo.
Uterine (Menstrual) Cycle
What are the three phases of the uterine cycle?
Menstrual phase (Days 1-5): Endometrial lining sheds due to low estrogen and progesterone levels.
Proliferative phase (Days 6-14): Rising estrogen levels rebuild the endometrial lining.
Secretory phase (Days 15-28): Progesterone prepares the endometrium for implantation.
What hormonal changes occur if fertilization does not happen?
The corpus luteum degenerates, progesterone and estrogen levels drop, and menstruation begins.
Female Sexual Response
What are the major physiological changes during female sexual arousal?
Increased blood flow to the clitoris, vaginal lubrication, and rhythmic contractions of pelvic muscles.
What neurotransmitter plays a key role in female sexual arousal?
Nitric oxide (NO), which promotes vasodilation.
Pregnancy and Hormonal Changes
What hormonal changes occur during puberty in females?
Increased secretion of GnRH, stimulating FSH and LH release.
Estrogen leads to breast development, wider hips, and the onset of menstruation.
What is the role of relaxin during pregnancy?
It loosens the pubic symphysis and softens the cervix for labor.
What are the major hormonal changes during pregnancy?
hCG: Maintains the corpus luteum and prevents menstruation.
Estrogen: Promotes uterine growth and mammary gland development.
Progesterone: Maintains the endometrium and inhibits uterine contractions.
Puberty and Menopause
What is menopause, and what causes it?
The permanent cessation of menstruation due to ovarian follicle depletion and declining estrogen level
What are the symptoms of menopause?
Hot flashes, vaginal dryness, osteoporosis, mood swings, and increased cardiovascular risk.
Clinical Conditions Related to Female Reproduction
What is polycystic ovary syndrome (PCOS), and what are its symptoms?
A hormonal disorder characterized by irregular ovulation, excess androgen levels, and ovarian cysts. Symptoms include acne, hirsutism, and infertility.
What is endometriosis?
A condition where endometrial tissue grows outside the uterus, causing pain and infertility.
What is the most common cause of female infertility?
Ovulatory disorders, such as PCOS or premature ovarian failure.
Reproductive System Lecture 4
🧬 Fertilization & Early Embryonic Development
How long after ovulation is an egg viable for fertilization?
roughly 24 hours
How long can sperm remain viable in the female reproductive tract?
up to 5 days
What is sperm capacitation and why is it important?
A maturation process occurring in the female tract that makes sperm capable of fertilizing an egg. It involves increased motility and plasma membrane fragility, allowing the acrosome reaction.
What is the role of seminal fluid in capacitation?
It contains factors that inhibit capacitation until the sperm is in the female reproductive tract.
In IVF, how is capacitation achieved?
By washing sperm or using a Percoll gradient to remove inhibitory factors.
🧫 Acrosome Reaction & Polyspermy Prevention
What triggers the acrosome reaction?
Binding of the sperm to the zona pellucida of the oocyte.
- Approach
- Acrosomal Reaction (binds to zona-pellucida)
- Binding (Oocyte plasma membrane sperm binding receptor)
- Fusion (sperm and oocyte plasma membrane)
- Block to poyspermy (Oocyte membrane block, cortial reaction).
Why must the acrosome reaction happen only after binding to the zona pellucida?
To ensure that only sperm in the correct location release enzymes to penetrate the oocyte.
What is polyspermy, and how is it prevented?
Fertilization by more than one sperm. Prevented by:
Fast block: Depolarization of oocyte membrane.
Slow block: Cortical reaction alters zona pellucida to block further sperm
🧫 Zygote to Blastocyst Development
What is a zygote?
A fertilized egg cell with a fused 2N nucleus from male and female pronuclei.
Define morula and blastocyst.
Morula: Solid ball of 16+ cells.
Blastocyst (burrows into endometrium): Hollow structure with inner cell mass (embryoblast) and outer trophoblast layer.
Implantation of Blastocyst:
Day 4: early blastocyst floats in uterine cavity, degenerates from zona pellucida.
Day 6: Blastocyst adheres to uterine wall.
Day 7: Implementation as trophoblast invades uterine wall. Cytotrophoblast (inner cellular layer); syncytiotrophoblast (outer multinucleatide invasice layer).
Day 9: implantation continues - embryonic disc (bilayer) - epiblast, hypoblast.
Day 11: implantation complete. amniotic sac, yolk sac form.
Conception to 2 weeks - Germinal Period
3 to 8 weeks - Embryonic Period
9 weeks to term - fetal period
Epiblast’s three categories:
Ectoderm, mesoderm, endoderm
Ectoderm: Gives rise to the skin, nervous system, and sensory organs.
Mesoderm: Forms muscles, bones, circulatory system, and other connective tissues.
Endoderm: Develops into internal organs such as the lungs, liver, and digestive system.
See diagram
When does implantation occur?
round day 6 after fertilization.
What will the trophoblast become?
Part of the placenta and structures interfacing with maternal blood.
Placentation:
Maternal and fetal blood supplies, are NOT in direct contact; nutrient, gases, wastes, diffuse through: trophoblast layer, mesenchyme, fetal capillary endothelium.
Normal term Placenta is
500 g,. 15-20 cm in diam. 2-3 cm thick.
FYI: umbilical cord: 50-70 minutes in length
🩸 Placenta & Hormonal Regulation
What are the two major functions of the placenta?
Exchange of nutrients, gases, and waste.
Endocrine function (hormone production).
What is the main function of hCG?
Maintains the corpus luteum to sustain progesterone and estroge* secretion in early pregnancy.
- can detect pregnancy 3 days after missed period.
Missed period is based on what:
detection of hCG in blood or urine.
What is the function of human placental lactogen (hCS/hPL)?
Promotes breast development.
Supports fetal bone growth.
Increases maternal glucose availability (by lowering insulin sensitivity). - or there is also placental growth hormone that stimulate lipolysis, and gluconeogenesis to support fetal growth.
How does estrogen support pregnancy?
Maintains endometrium, supports breast development, and gradually takes over from the corpus luteum.
What is the source and function of progesterone during pregnancy?
Initially from the corpus luteum, later from the placenta. It relaxes smooth muscles (e.g., uterus, GI tract, ureters, GE sphincter, intestines).
🧍♀️ Maternal System Changes
Why do pregnant women experience physiological anemia?
Blood volume increases (~40%), but plasma increases more than RBCs.
- Pulse increase. by 15-20 beats/min in 3rd trim.
- Nausea is caused by increased progesterone and hCG levels. can lead to hyperemesis gravidanum.
What causes myocardial hypertrophy during pregnancy?
Myocardial hypertrophy is due to increased contractility and cardiac output (CO).
When does blood pressure decrease to its lowest during pregnancy?
Blood pressure decreases slowly to its nadir at around 24 weeks of pregnancy.
Why is there an increased risk of UTIs during pregnancy?
High progesterone decreases bladder tone and increases urinary stasis.
How much do the kidneys increase in length during pregnancy?
Kidneys increase in length by 1-1.5 cm due to increased renal blood flow.
How does bladder capacity change during pregnancy?
Bladder capacity nearly doubles, and bladder tone decreases.
How does glomerular filtration rate (GFR) change in early pregnancy?
GFR increases by 30-50% in the first trimester.
What hormonal effects impact renal function during pregnancy?
High progesterone promotes Na and water loss, while increased aldosterone and estrogen promote salt and water retention.
Why is there an increased risk of urinary tract infections during pregnancy?
The increased risk is due to reduced bladder tone, which can lead to urinary stasis, and hormonal changes that affect the urinary tract.
What are Braxton Hicks contractions?
Irregular uterine contractions during pregnancy that are not coordinated labor contractions.
What causes pregnancy-related nausea?
Likely increased levels of hCG and progesterone.
What fetal structures bypass parts of circulation?
Foramen ovale: Shunts blood from right to left atrium.
Ductus venosus: Bypasses liver, directing blood toward the heart.
Reproductive System Lecture 5
👶 Parturition (Labour & Delivery)
What are the three stages of parturition?
Dilation – Cervix dilates to 10 cm; longest and most variable stage.
Expulsion – From full dilation to delivery of the baby.
Placental – Delivery of the placenta, usually within 30 minutes.
Which fetal hormone helps initiate parturition and why?
Fetal cortisol; it may trigger labour and stimulates surfactant production in fetal lungs—critical for postnatal breathing.
What is the significance of high estrogen levels near term?
Increases oxytocin receptor expression in myometrium.
Antagonizes the relaxing effects of progesterone to promote uterine contractions.
What are the two key hormones in labor and their sources?
Oxytocin – from maternal posterior pituitary.
Prostaglandins – from placenta and uterus.
🔁 Neuroendocrine Feedback & Hormonal Triggers
Why doesn’t high oxytocin in late pregnancy trigger labor immediately?
Because progesterone levels are still high and oxytocin receptor density on the uterus is initially low.
What triggers the neuroendocrine reflex to initiate labor?
Pressure from the baby’s head on the cervix → stimulates oxytocin release → stimulates prostaglandin synthesis → promotes uterine contractions (positive feedback).
How do contractions contribute to placental delivery and reduced bleeding?
They compress uterine blood vessels, detach the placenta, and limit postpartum bleeding.
🍼 Lactation: Hormonal Regulation
What is the structure responsible for milk production in the breast?
The alveolus, lined with milk-secreting epithelial cells.
Which hormones stimulate breast development during pregnancy?
Estradiol and progesterone (promote alveolar and ductal growth).
Prolactin, glucocorticoids, hCS (support and permit development).
Why is actual milk secretion minimal during pregnancy despite prolactin presence?
High estradiol and progesterone inhibit prolactin’s full action on milk secretion.
What change postpartum allows milk secretion to begin?
Drop in estradiol and progesterone, removing the inhibition on prolactin action.
💧 Milk Let-down Reflex
Which hormone is responsible for milk production, and what does it stimulate?
Prolactin – stimulates synthesis of casein, lactose, and fatty acids.
Which hormone is responsible for milk ejection (let-down), and how?
Oxytocin – causes contraction of myoepithelial cells around alveoli.
What maintains continued lactation postpartum?
Continuous nursing stimulation (suckling) → maintains prolactin and oxytocin release via neuroendocrine reflexes.
🍽️ Nutrition During Pregnancy
What key nutrients are crucial during pregnancy and why?
Vitamins:
Vitamin D – bone health
Folic acid – prevents neural tube defects
Vitamin K – clotting
Minerals:
Iron – prevent anemia
Calcium – fetal bone development
