SUGER Flashcards
What capillaries make up the glomerulus? and therefore the endothelial lining is
Fenestrated capillaries
fenestrated
What arteriole is blood fed into glomerulus
Afferent arteriole
What arteriole drains the glomerulus
efferent arteriole
How many layer are there within the glomerular basement membrane
3
Endothelial side
Lamina Rara Interna (Heparan sulfate)
Lamina Densa (Type 4 collagen, laminins)
Lamian Rara Externa (Heparan sulfate)
Podocyte layer
What is/isn’t allowed to enter the bowman’s capsule
Formed elements not allowed + negatively charged substances
Elements such as H2O, small proteins, nutrients + positively charged substances allowed in
What are the layers of the bowman’s capsule ?
Parietal (simple squamous epithelial cells)
Visceral (podocytes)
What is the space between podocytes called?
Filtration slits
What protein spans across adjacent podocytes?
Nephron because they span across filtration slits they are called Nephron diaphragm
What is the role of a mesangial cell?
Phagocytose any macromolecule that gets stuck in the slit diaphragm
Contractile ability - afferent/efferent arterioles
Bind to JG cells to secrete renin
What is glomerular filtration rate?
Plasma volume that is being filtered out of glomerulus and into Bowmans capsule for every 1 minute 125ml/min
What factors affect glomerulus filtration rate?
Net filtration pressure: Pressing forcing out - Pressure forcing in
Pressure forcing out = glomerular hydrostatic pressure + colloid osmotic pressure
Pressure forced in = colloid osmotic pressure + capsular hydrostatic pressure
Permeability of glomerulus + Surface Area= Filtration Coefficient
GFR= NFP x KF
Relationship between NFP & GFR
Directly proportional
Relationship between GFR and Filtration coeffeicent
Directly proportional
What makes up the filtration co-efficient
surface area + permeability of glomerulus
What is the GHP and BP relationship
directly proportional and therefore dependent on systemic circulation
What is osmolality
Volume of particles per kg of solvent
OSMOLALITY = moles/kg
What is tubular secretion
Substances flowing from blood to kidney tubules (active transport)
What is tubular reabsorption
Substances flowing from tubules to blood
Active or passive
Proximal tubule bulk reabsorption
3Na+/2K+ ATPase pumps
Secondary Active transport: Na+ &Glucose/amino acids/lactate channel
Secondary Active transport: Na+ & H+ pump. H+ combines with HCO3- in a proximal convoluted tube to form H2CO3. This then with the enzyme carbonic anhydrase goes to become H20 + CO2
Paracellular transport
Urea is also reabsorbed via lipid
What substances have a 100% reabsorption
Glucose
Amino Acids
Lactate
What is obligatory water reabsorption
When the water is following the actual salt into the blood
By which transport mechanism is drugs undergo tubular secretion
Active transport
What is the importance of tubular secretion
Might not be able to get rid of that substance because it got reabsorbed too much/or couldn’t filter/lipid-soluble
What happens to the osmolality as you go from renal cortex to renal medulla
Increases therefore have less H20 in comparison to solutes which is high = hypertonic
What two things make up the loop of Henle
Ascending limb
Descending limb
What makes up the nephron
Bowman’s Capsule, Glomerulus, PCT, DCT, Loop of Henle
What is the name of the cotransporter found in ascending limb of Loop of Henle?
Na+/K+/Cl- co transporter
Reabsorbs all of Na+ and Cl- and some of K+ into blood
What is the Counter Current Exchange Mechanism
When the ascending limb goes up and pumps out Na+, K+, Cl- with the cotransporter making the medullary interstitial space salty.
This causes the water travelling down the descending limb to leave via aquaporin 1 (obligatory water reabsorption)
Water leaves the descending limb until the kidney tubules plasma osmolality is equal to descending limb isotonic
Why cant solutes leave out of the descending limb
Or water leave ascending limbs
The descending limb is impermeable to solutes
The ascending limb is impermeable to water
What is the osmolality in the distal convoluted tube
Hypotonic as most of the solutes have left through the cotransporter in comparison to the plasma osmolality
What is the vasa recta
peritubular capillary in the medulla
branch of efferent arteriole
slow blood flow
Parallel to the loop of Henle
Involved in the counter current multiplier system
What happens in the vasa recta
There is a high concentration of NaCl in the instertial fluid. Moves into the vasa recta as the osmolality increases as you go down vasa recta. At the same time high conc of H20 moves from vasa recta to instertial fluid
As osmolality decreasesas you go up vasa recta NaCl is being pushed out. H2O moves back in
Counter Current Multiplier mechanism significance
Prevents the rapid removal of sodium chloride from the medullary interstitial in order to maintain sality gradient
Delivers O2 to tissues
How is calcium reabsorbed in the early distal convoluted tubule
Low Ca+ levels detected by chief cells causes parathyroid to secrete parathyroid hormone.
Parathyroid hormone binds to receptors distal convoluted tubule then causes adenyl cyclase mechanism opening up Ca2+ channel.
Calcium reabsorbed then by secondary calcium channel
What drug inhibits the sodium chloride symporter in the early distal convoluted tubule
Thiazide
Its a diuretic
What does the adrenal gland secrete
Aldosterone
Stimulates: Angiotensin 2, Na+ concentration
Inhibit: Low K+ levels
What is distal convoluted tubule impermeable to?
Water
What are principal cells responsible for?
Maintaining mineral balance in cells
What are intercalated A and B cells
maintaining acid-base balance
Where intercalated cells found
Collecting duct
What do intercalated A cells secrete
What do intercalated B cells secrete
Acid
Base
What secretes ADH
Pituitary gland
What stimulates the release of ADH
Increase in osmolality
Angiotensin 2
What cells do ADH act on and where can the be found?
Collecting duct
Act on principal cells
What cells make up collecting duct
Principal cells
Intercalated cells
What happens once ADH binds to receptor of principal cells
Stimulates Gs protein
Goes to adenyl cyclase and converts ATP in cAMP
cAMP —-> pKa
pKa results in the fusion of vesicles containing aquaporins to go to collecting duct membrane
What ions depend on the hormone secreted and therefore reabsorbed into blood stream.
Where can this be found
Principal cells
Amount of Aldosterone present depends on Na+ that is being reabsorbed in late distal convoluted tubule
What is urea recycling
urea is secreted at the last part of the collecting duct via facilitated diffusion and gets reabsorbed by ascending limb.
Importance:
1, Make concentrated urine
2. Wants to contribute to medullary interstitial gradient
What happens to urine
Most goes down collecting tubule
Some gets recycled
What is absorbed by Proximal convoluted tube
Na+ (65%)
H2O (65%)
HCO3- (90%)
K+ (60%)
Cl- (50-60%)
Ca+ (60%)
Urea (50%)
Glucose, Amino Acids, Lactase (100%)
Vasa recta
parallel to loop of Henle
What is secreted into Proximal Convoluted tube
Drugs
H+
NH4+
Creatinine
=All require ATP
What is absorbed by Loop of Henle
Descending limb
25% water
Ascending limb
Na+ : 25%
K+ : 30%
2Cl- : 30%
What happens in parietal cell of distal convoluted tube when there is low bp
Zona glomerulosa secretes aldosterone
Stimulates genes and secretes 3 proteins in principal cell
One of the proteins allows sodium to enter the principal cell
Another protein allows 3Na+/2K+
Another one is to secrete potassium K+ into the late distal convoluted tube
ADH secretes causes aquaporin to open up
Intrinsic renal autoregulation
Myogenic mechanism
Tuboglomerular feedback system
Myogenic mechanism renal autoreg
High BP
⇡BP ⇢ ⇡G.H.P ⇢ ⇡G.F.R
⇡BP ⇢ ⇡Stretch⇢ ⇡contraction ⇢ ⇡vasoconstriction ⇢ ⇣GBF ⇢ ⇣GFR
⇡BP ⇢ ⇡G.F.R ⇢ high or low NaCl
high
Macula Densa
⇑Na+ ⇑Cl-
Adenosine
causes afferent arteriole to constrict by acting on smooth muscle cell- vasoconstriction smaller diameter and therefore lower GBF, less filtration and lower GFR lower NaCl
Inhibits JG cells to secrete renin
Macula Densa
⇓Na+ ⇓Cl-
NO PGI2
causes afferent arteriole to dilate by acting on smooth muscle cell - vasodilation larger diameter and therefore ⇡ GBF, ⇡ filtration and ⇡ GFR ⇡ NaCl
Stimulates JG cells to secrete renin
Extrinsic renal autoregulation
Sympathetic N.S (⇣SBP)
RAAS
Sympathetic nervous system
SNS gets activated when BP is really low
- Increases heart rate, increases stroke volume to increase cardiac output and bp
- Causes the vasoconstriction of the afferent arterioles to get more blood flow to other organs
- Causes vasoconstriction of the systemic arteries via alpha 1 receptor to increase bp triggers renin release from beta 1 receptors
Renin Angiotensin Aldosterone ADH System (RAAAS)
When there is low BP.
Low Bp ⇢ Low GFR
JG cells secrete more renin
renin causes angiotensinogen which is secreted by the liver to cleave and become angiotensin 1
Angiotensin 1 combine with Angiotensin converting enzyme (ACE) in the lungs and cleaves it to become angiotensin 2
AT2 affects other systems
What does angiotensin 2 do in PSNS? R.A.A.S
In CNS: Increase in thirst
In CNS: This causes the increase of ADH to be secreted by the `pituitary gland affecting the collecting tubule to become more permeable to H20. This increases the BV and therefore BP
In the adrenal cortex: binding to the zona glomerulosa secretes more aldosterone causing the increase of absorption of Na+ and H20 of parietal cells in DCT. This increases the BV and therefore BP
In kidneys: Binds to receptors of efferent arterioles and causes vasoconstriction and therefore increases GFR. Binds to cells of PCT via receptors and causes it to increase the reabsorption of sodium and water. Increasing BV and then BP
In systemic arterioles: causes vasoconstriction, increase in SVR, increase in BP
What does ADH do?
Put aquaporins in the tubular membrane, water can therefore be funnelled in tubular cells and into the blood.
What makes up the urinary bladder
Detrusor muscle
Internal & External urethral sphincter
urogenital diaphragm
Receptors in what muscle of the urinary bladder contain stretch receptos
Detrusor muscle
Mechanism of micturition of empty bladder
Receptors in the urinary bladder detect low action potential in the sacral spinal cord S2-S4
Stimulates neurons that will take these ascending fibres upwards into the thoracolumbar region of the spinal cord T11-L2 to synapse with preganglionic motor neurons
Then they synapse on the cell bodies of the inferior mesenteric ganglion
The hypogastric nerve carries impulses and attaches to detrusor muscles (relax). Secretes NE, which attaches to the receptor. NE also binds to receptors on the internal sphincter muscle (contract)
Impulses also carried up pons and cerebral cortex
This stimulates the pontine storage centre and inhibits the pontine micturition centre in the pons
impulses from the pontine storage centre and synapse with inferior mesenteric ganglion. They also carry down to preganglionic motor neurons.
Impulses carry to the detrusor muscle and secrete Ach, increasing Ca+ in muscles and causing contraction.
There are also impulses carried to the anterior ventral horn of the sacral spinal cord and synapse with cell bodies. The impulses travel to the pudendal nerve and bind to nicotinic receptor
Main contents of urine
95% H2O
rest are ions
uric acid
drugs
toxins
How much urine is stored in an empty bladder
10-20ml
What is it called when glucose is in urine
Glycosuria → diabetes mellitus
High amounts of protein in the urine
Caused due to an increase in BP glomerulonephritis, heart failure
>150mg/day urine 1st sign of renal disease
Name the 3 things to make up the Glomerular Filtration barrier.
- Fenestrated capillary endothelium.
- Double layer basement membrane.
- Foot processes of podocytes.
Name 5 factors that determine a molecule crossing the filtration barrier.
- Pressure.
- Size of the molecule.
- Charge of the molecule (negative molecules are repelled).
- Rate of blood flow.
- Binding to plasma proteins.
What force favours glomerular filtration?
Hydrostatic pressure of the glomerular capsule.
Name 2 forces that oppose glomerular filtration.
- Hydrostatic pressure of the bowman’s space.
- Oncotic pressure of the glomerular capsule.
Does the bowman’s space exert an oncotic pressure?
No. There are no proteins in the Bowman’s space.
What equation could be used to calculate the net glomerular filtration pressure?
HPgc - HPbs - πgc
What effect does vasoconstriction of the afferent arteriole have on GFR?
GFR will decrease as the HPgc decreases.
What effect does vasodilation of the afferent arteriole have on GFR?
GFR will increase as the HPgc increases.
What effect does vasoconstriction of the efferent arteriole have on GFR?
GFR will increase. Efferent arteriolar constriction tends to push blood back to the glomerulus and so increases the HPgc.
What effect does vasodilation of the efferent arteriole have on GFR?
GFR will decrease as the HPgc decreases.
What is tubuloglomerular feedback?
Macula densa cells of the DCT detect NaCl levels and use this as an indicator of GFR.
NaCl levels increase as GFR increases.
Where are the macula densa cells located?
They are epithelial cells found within the DCT. They sit between the afferent and efferent arteriole of the glomerulus.
How could you measure GFR?
Look at the excretion of a marker substance.
List 3 qualities necessary of a marker substance.
- Freely filtered.
- Not metabolised.
- Not reabsorbed or secreted.
What substance can be used clinically to estimate GFR?
Creatinine.
What is the usual value of the filtration fraction?
20%
Define renal clearance.
Volume of plasma from which a substance is completely removed by the kidney per unit time.
How much H2O do we intake in a day?
2.5L
How much salt do we intake in a day?
10g
What is the equation for plasma osmolality?
2(Na + K) + glucose + urea
How is tonicity regulated?
By controlling the H20 movement.
Is ADH a vasoconstrictor or a vasodilator?
Vasoconstrictor.
How is fluid volume regulated?
By controlling Na+ movement.
List the 3 main triggers for the release of Renin.
- Sympathetic stimulation.
- Low BP detected by afferent arteriole.
- Low Na+ detected by macula densa cells.
What is the function of ACE?
Converts angiotensin 1 into angiotensin 2.
What is the function of atrial natriuretic peptide (ANP)?
ANP is a renal vasodilator. It inhibits aldosterone release induced by Angiotensin 2 and it closes ENaC channels
What channels do loop diuretics target?
NKCC2
What channels do Thiazides target?
NCC
Name 3 types of drugs you could give to someone with hypertension.
- Diuretics.
- Vasodilators.
- ACE inhibitors.
Name 3 urinary buffers.
- Ammonium.
- Phosphate (commonest urinary buffer).
- Bicarbonate.
How does respiratory acidosis effect the ammonium buffer?
The uptake and synthesis of ammonia is increased.
Is renal compensation to an acid/base disturbance fast or slow?
Slow. Respiratory compensation is fast.
What is the renal compensation mechanism for respiratory acidosis?
Increased ammonia production. H+ secretion increases and HCO3- reabsorption increases.
What is the renal compensation mechanism for respiratory alkalosis?
H+ secretion decreases and HCO3- reabsorption decreases.
What is the respiratory compensation mechanism for metabolic acidosis?
Chemoreceptors are stimulated enhancing respiration. PaCO2 decreases.
What is the respiratory compensation mechanism for metabolic alkalosis?
Chemoreceptors are inhibited reducing respiration. PaCO2 increase.
What does erythropoietin (EPO) do?
Stimulates bone marrow, promotes RBC maturation.
What is the role of the Kidneys in Vitamin D activation?
Converts 25-OH D into 1,25-diOH D. (Enzyme: 1-hydroxylase)
What is the diff between a male and female urinary bladder
Female urethra doest have a prostate and an external sphincter
The urethra is also shorter
Receptors of urinary bladder involved in micturition
Detrusor muscle: M3 receptor & B3 receptor
Internal sphincter: alpha 1 receptor
External sphincter: nicotinic receptor
The three important efferent nerves involved in micturition
Comes from the sacral region: pelvic nerve (parasympathetic) Ach-> M3 receptor
Increased stimulation leads to contraction of the detrusor muscle
Comes from sacral region: pudendal nerve (somatic) Ach-> nicotinic
This leads to the external sphincter contract
SNS system: Presynaptic ganglion -> Post sympathetic fibre (Hypogastric) NA-> B3 receptor. relaxation of the detrusor muscle
Presynaptic ganglion -> Post sympathetic fibre (Hypogastric) NA-> alpha 1 receptor -> relaxation of internal sphincter
The sensory afferent nerve involved in micturition called
Pelvic nerve attached to detrusor muscle
Full bladder micturition
Voiding Reflex
Afferent nerve fibres send impulses goes to ventral grey horn → interneurons → parasympathetic efferent fibres causes contraction of detrusor muscle
What are the 4 main layers of the epidermis of the skin?
- Keratinised squames.
- Granular layer.
- Spinous layer (the thickest layer).
- Germinative layer.
What is the role of Filaggrin?
Produces natural moisturising factor.
Why are protease inhibitors in the skin important?
Protease inhibitors prevent the breakdown of corneodesmosomes.
What is the ideal pH of the skin?
5.5
What is the SRY protein called?
Testis determining factor: under its influence male development takes place.
What is the importance of testis determining factor?
Under its influence male development takes place.
What cells are responsible for secreting testosterone?
Interstitial cells of Leydig.
What is the blood supply to the upper 2/3 of the anal canal?
The superior rectal artery (branch of IMA).
What is the blood supply to the lower 1/3 of the anal canal?
The inferior rectal artery (branch of internal pudendal artery).
What part of the anal canal receives autonomic innervation?
The upper 2/3 (lower 1/3 is somatic innervation).
Which anal sphincter receives autonomic innervation and is involuntary?
The internal anal sphincter.
Which urethral sphincter is composed of smooth muscle?
The internal urethral sphincter.
When is the periaqueductal grey suppressed?
In storage. (Active in voiding).
What is the external urethral sphincter?
Skeletal muscle, voluntary sphincter.
Composed of the rhabosphincter and pelvic floor.
Do the urethral sphincters receive parasympathetic or sympathetic innervation?
Sympathetic.
When are the urethral sphincters activated?
In storage - activation causes contraction of the sphincters.
Spermatogenesis: what do type B cells differentiate into?
They differentiate into primary spermatocytes that will then go onto meiosis.
Spermatogenesis: where are type A cells located?
Outside the blood-testes-barrier.
Spermatogenesis: what does meiosis 1 produce?
2 secondary spermatocytes.
Spermatogenesis: what does meiosis 2 produce?
4 spermatids.
What changes does the sperm make with regards to its structure?
- It discards excess cytoplasm.
- Grows flagellum.
- Lots of mitochondria.
- Acrosomes at its head.
What is the function of the epididymis?
Storage and maturation of sperm. Sperm normally stay in the epididymis for 60 days.
What is the affect of FSH on the testes?
Stimulates spermatogenesis and sertoli cells. Sertoli cells produce MIF (mullerian inhibiting factor) and inhibin and activin which acts on the pituitary gland to regulate FSH.
What is the affect of LH on the testes?
Stimulates Leydig cells to produce testosterone.
What is ovulation?
The release of an oocyte from a follicle.
What hormone stimulates ovulation?
LH.
In humans, is the sex of the embryo determined by the sperm or egg?
The sperm - can contribute an X or Y. The egg is always X.
What is the secretory phase?
When the corpus luteum releases progesterone and the endometrium generates blood vessels and proteins etc needed for the implantation of a fertilised embryo.
What is the proliferative phase?
When the endometrium grows rapidly under the influence of oestrogen.
What does the corpus luteum degenerate into?
The corpus albicans.
What is capacitation?
The final stage of sperm maturation that occurs in the female genitalia. Before this spermatozoa would be unable to fertilise an oocyte.
What is block to polyspermy?
After a sperm has fertilised the egg, the egg needs to prevent further sperm fertilising it.
What are the mechanisms to ensure block to polyspermy?
Enzymes are released that harden the zona pellucida and inactivate sperm binding sites.
What hormone does the hypothalamus release that stimulates release of the gonadotropins?
GnRH - gonadotropin releasing hormone.
What cells does FSH act on in males?
Sertoli cells.
What cells does FSH act on in females?
Granulosa cells.
What cells does LH act on in males?
Leydig cells.
What cells does LH act on in females?
Theca cells.
What is the function of sertoli cells?
They release MIF, inhibin and activins (regulate FSH secretion), and androgen binding protein (increases testosterone concentration).
What is the function of granulosa cells?
They convert androgens into oestrogen using aromatase enzyme.
What is the function of leydig cells?
they produce testosterone.
What is the function of theca cells?
They produce androgens (oestrogen precursors) which diffuse into granulosa cells to form oestrogen.
What enzyme converts androgens into oestrogen?
Aromatase.
What is the predominant hormone responsible for the proliferative phase?
Oestrogen.
What is the predominant hormone responsible for the secretory phase?
Progesterone.
Where do primordial germ cells originate from in the embryo?
The epiblast.
Until what week are male and female primitive gonads identical?
Week 6.
What is the mesovarium?
Mesentery attaching the ovary to the posterior broad ligament.
Define menopause.
Cessation of menstruation.
What physiological changes happen in menopause?
There is depletion of the primordial follicles. Oestrogen levels decrease; FSH and LH therefore increase as they’re not inhibited by negative feedback.
What happens to oestrogen levels at menopause?
They fall.
What happens to LH and FSH levels at menopause?
They increase as they’re no longer inhibited by negative feedback.
What are the short-term symptoms of menopause?
Hot flushes, night sweats, palpitations, irritability, lethargy, decreased libido, vaginal dryness, vaginal pH change, dry skin and hair, brittle nails.
What are the long-term symptoms of menopause?
Osteoporosis and increased risk of cardiovascular disease.
Name 4 treatments that can help with the symptoms of menopause.
- HRT.
- Sedatives.
- Calcium supplements.
- Vitamin D supplements.
What hormones are given in HRT?
Oestrogen and progesterone.
What is the advantage of HRT being given as a patch as opposed to orally?
The hormones go straight into the bloodstream and so bypass the liver.
What are the risks of HRT?
Small increased risk of cervical, breast and endometrial cancer.
What are the two main types of stem cells?
- Embryonic stem cells - pluripotent.
- Somatic stem cells - multi-potent.
Name 3 diseases that stem cells could help to cure.
- Parkinsons disease.
- Alzheimers.
- Type 1 diabetes.
What are the 3 main characteristics of stem cells?
- Self renew over long periods.
- Undifferentiated.
- Can generate other cells: pluripotent/multipotent.
Where in the embryo do embryonic stem cells come from?
The inner cell mass.
What are the 3 histological layers of the uterus?
- Endometrium - mucosal lining, pseudostratified columnar.
- Myometrium - smooth muscle wall.
- Perimetrium.
What is the function of the smooth muscle in the myometrium?
It helps the uterus to expand and acts to protect the foetus. It also provides a mechanism for foetal expulsion.
What are the characteristics of the endometrium in the proliferative phase?
Straight glands, no secretions. Stromal and epithelial mitoses.
What are the characteristics of the endometrium in the early secretory phase?
Coiling of glands and subnuclear vacuoles
What is the decidua basalis?
A part of the endometrium invaded by trophoblast.
What is the decidua capsularis?
A part of the endometrium overlying the blastocyst.
What is the decidua parietalis?
Endometrium lining the rest of the uterine cavity.
What invades the decidua basalis?
Syncytiotrophoblast.
What is the role of the syncytiotrophoblast?
Uptake of oxygen and nutrients from the maternal blood.
Release of CO2 and waste products into the maternal blood. The exchange surface is gradually increased during maturation due to branching of the villi.
What is the role of the cytotrophoblast?
Forms solid masses covered by syncytiotrophoblast - primary chorionic villi. These masses become filled with stroma, forming secondary chorionic villi. Capillaries appear in the stroma – tertiary chorionic villi.
What hormonal pathway is likely to be responsible for a decrease in urine production?
Renin angiotensin aldosterone system.
Why is it important that the chorionic villi branch in maturation?
Branching increases the surface area for exchange of nutrients.
Why can a tumour of the pituitary gland affect vision?
The optic chiasm lies just above the pituitary gland and is likely to be affected if there’s a tumour.
What are the two types of hormone?
- Made at response e.g. steroids.
- Stored and released at response e.g. pituitary hormones (peptides).
Where are the receptors for steroid hormones located?
Steroid receptors are intracellular - steroids pass through plasma membranes bound to proteins.
Where are the receptors for peptide hormones located?
On cell membranes.
What are the purposes of the endocrine system?
- Communication between cells.
- Integrates whole body physiology.
- It can make rapid adaptive changes.
- Maintains the metabolic environment.
Briefly describe the mechanism of ACTH.
Hypothalamus -> CRH -> anterior pituitary -> ACTH -> adrenal glands -> cortisol release -> negative feedback on hypothalamus and pituitary.
Briefly describe the mechanism of LH and FSH.
Hypothalamus -> GnRH -> anterior pituitary -> FSH/LH -> sertoli cells, leydig cells/granulosa cells, theca cells -> oestrogen, testosterone, inhibin -> negative feedback on hypothalamus and pituitary.
How would you describe growth hormone secretion from the anterior pituitary?
It is secreted in a pulsatile fashion and increases during deep sleep.