GENITOURINARY Flashcards
what makes up the glomerular filtration barrier
fenestrated endothelium, Glomerular basement membrane (double thickness), podocyte foot processes
how much of the cardiac output does the kidney receive
20 % - 1L
what size of molecule can pass through the filtration barrier
10kDa or smaller
is the glomerular basement membrane positively or negatively charged
it is negatively charged - through heparin sulphate
what can pass through the glomerular filtration barrier
glucose, amino acids, creatinine, sodium, potassium, urea, bicarbonate disulphide and chloride
what are mesangial cells
they are modified smooth muscle cells - for support
what factors effect glomerular filtration
hydrostatic pressure out the capillary
hydrostatic pressure out of bowman’s capsule
oncotic pressure in the capillary
together they make the net filtration pressure
what is the only protein that should be found in urine
Tamm Horsfall
how do you calculate the GFR
NFP X kF (filtration coefficient)
what is the average GFR
125ml/min
what substance is used to measure GFR in clinic
creatinine
why is creatinine used to measure GFR
it isnt metabolised, it isnt secreted or absorbed by the tubules and it is freely filtered
how much plasma is filtered in 24 hours
180L in 24 hours (3L of plasma at 125ml every minute)
what is renal clearance
it is a measure of how much a substance is secreted/absorbed
how long a particular substance is removed from the plasma by the kidney and excreted in the urine
what happens to arterioles to increase the GFR
dilate the afferent arteriole and constrict the efferent arteriole. it increases the blood at the renal capsule
what happens to the arterioles to decrease the GFR
constrict the afferent arteriole and dilate the efferent arteriole. it decreases blood in the renal capsule
what cells are involved in tubuloglomerular feedback
the juxtagloerular apparatus
what cells detect a decrease in NaCl
the macula densa cells - in the distal convoluted tubule
what cells detect a decrease in the blood pressure
the granular cells of the afferent arteriole
what happens when there is a decrease in sodium and blood pressure in the kidney
then renin is secreted from the glomerular cells which acts in the RAA system
what is reabsorbed in the proximal convoluted tubule
glucose, amino acids, lactate, sodium, phosphate, bicarbonate, hydrogen ions, water and chloride
what is secreted in the proximal convoluted tubule
organic ions
what is the main driver of reabsorption of sodium ions
the Na/K ATPase basolaterally - builds up the concentration of sodium
what molecules do sodium cotransport
glucose, amino acids and lactate
what is sodium antiported with in the proximal convoluted tubule
it is antiported with H+ (maintains electrical charge)
how is HCO3- reabsorbed
tubular sodium/hydrogen antiporter. H+ and HCO3- in the lumen forms H2CO3 (via carbonic anhydrase) which then dissociated to H20 and CO2. CO2 diffuses into the RCT cell and H2O moves in via aquaporins. in the cell CO2 and H2O combine (carbonic anhydrase) to H2CO3 and this dissociates to H+ and HCO3-.
H+ is antiported into lumen
HCO3- basolaterally absorbed into capillary
what are the two sections of the loop of henle
the thin descending and the thick ascending
where in the loop of henle is water reabsorbed
in the thin descending loop
where in the loop of henle are ions reabsorbed
in the thick ascending loop
how does the concentration gradients cause reabsorption in the loop of henle
the descending limb loses H2O and ions remain. Therefore there is an increased concentration. In the ascending limb you lose Na and Cl with water remaining. therefore the concentration descreases
what channel transports Na+, K+ and 2CL- from the lumen into the LOH cell
the NKCC2 channel
what part of the RAA system acts on the NKCC2
aldosterone
what happens in the distal convoluted tubule
there is fine regulation of sodium, chlorine phosphate and water reabsorption
where are the macula densa cells found
in the distal convoluted tubule
what happens in the collecting duct of the kidney
there is water reabsorption and acid/HCO3- regulation
what are the two cell types found in the collecting ducts
the principal cells and intercalated cells
what are the features of the principal cells of the collecting duct
there are aquaporin 2 channels - responds to ADH action which increases water absorption
there are ENaC channels which is acted on by aldosterone. the result is more sodium reabsorption and potassium secretion
what are the intercalated cells in the collecting ducts for
it is involved in reabsorbing HCO3- and secreting H+
What is the distribution of fluid in the ICF and the ECF
42L
- 28L in ICF
- 14L in ECF - 11L in IF and 3L in plasma
what is plasma osmolarity
300 mOsm
what is fluid volume regulated by in the long term
RAA and ADH
what are the factors controlling potassium
diet and aldosterone
where is most of the potassium absorbed in the renal tubule
in the proximal convoluted tubule
where is ADH/vasopressin made in the body
it is manufactures in the hypothalamus
where is ADH /vasopressin secreted from
the posterior pituitary
what is ADH/vasopressin affected by
osmoreceptors (a small change activates ADH) and baroreceptors (these arent as sensitive so need a large change to activate)
what happens in the body when you drink a lot of water
there is a decrease in fluid mOsm which causes an inhibition of ADH release. this means there is less plasma AQDH and therefore there is an increase water excretion at the loop of henle and the collecting ducts
what happens if there is a decrease in the extracellular fluid in the body
there is an increase in baroreceptor firing, which cases stimulation of ADH release. this causes an increase in plasma ADH. and therefore there is a decrease in excretion of water at the LOH and CD
what is the RAA system
renin converts angiotensinogen to angiotensin 1. ACE (from the lungs) then converts angiotensin 1 to angiotensin2. angiotensin 2 causes release of aldosterone, as well as increased ADH stimulation and increased blood pressure (acts as a vasoconstrictor)
what is the main ECF ion
sodium - sodium determines blood pressure
where is aldosterone made
from the zona glomerulosa of the adrenal cortex
what is ANP
it is produced by cardia atrial myocytes when there is an increased blood pressure in response to atrial stretch. it is an antagonist to ENaC, aldosterone and increases GFRand increases sodium excretion.
what is the link between the parathyroid hormone and the kidney
parathyroid hormone is released from the parathyroid gland, when there is decreased calcium in the plasma. this directly increases calcium reabsorption. it stimulates the active form of vitamin D in the body as well (also involved in calcium absorption)
what is the average pH of the body
7.35 - 7.45
what is acidemia
when the environment is more acidic but it is still in the normal range
what is alkalemia
when the environment is more alkaline but still in the normal
what is the equation to calculate the anion gap
[[Na+]+[K+]] - [[Cl-]+[HCO3-]]
what is the main urinary buffer
HCO3-
what does the concentration of buffer molecules in acid/alkalosis depend on
the driving factor - the thing causing the change (acidosis/alkalosis)
compensation - trying to restore the normal
what is the kidneys endocrine function
- EOP (erythropoietin) which stimulates RBC maturation in the bone marrow, it is produced in the peritubular cells of the renal cortical interstitium
- activation of vitamin D
what causes an increase of EPO in the body
anaemia, altitude, cardiopulmonary disorders
what causes a decrease in EPO in the body
polycythemia (increased Hb abnormally in blood), renal failure
how does activation of vitamin D occur
calcediol (25-DeH VitD3) in the liver is transported to the kidney where it is activated to calcitriol (1,25 - vitaminD3). this then worked in the intestines, bone, kidney and parathyroid
what is the action of active vitamin D in the body
intestines - increased PO4 absorption and increase calcium
bone - increased reabsorption
Kidney - increased PO4 reabsorption and increased calcium reabsorption
parathyroid - decreased parathyroid hormone (low PTH inhibits bone resorption)
what is present in the walls of the bladder
detrusor muscles
what sort of muscle is present in the internal urethral sphincter
smooth muscle
what nerve stimulates the internal urethral sphincter
syplathetic nerve - hypogastric T1-L2
what muscle is present in the external urethral sphincter
skeletal muscle
what nerve innervates the external urethral sphincter
somatic pudendal nerve - s2, s3, s4
what happens during bladder filling
the detrusor relaxes, the internal and external urethral sphincter is shut = contracted (shut)
what happens to the bladder during micturition/pee
the detrusor muscle contracts (increased sympathetic tone) and the internal and external urethral sphincter relaxes (opens), due to a reduced sympathetic tone
what is the primitive bladder stretch reflex
when there is peeing (until childhood) due to a spinal reflex to a increased bladder filling.
what happens if the primitive bladder stretch reflex persists
you get an incontinence syndrome
what is the bladder and urinary tract function
store urine at a low pressure, fill to a comfortable volume (receptive relaxation). there is a voluntary initiation to peeing
when does the primordial germ cell migrate to the urogenital ridges
6 weeks
what causes female sex differentiation
when there is no SRY it means there are no leydig or sertoli cells meaning no testosterone and AMH (wolffian ducts regress). the Mullerian ducts develops, and with the action of oestrogen, the vagina, citerus, ovaries and ova is made
what causes male sex development
there is the presence of SRY, causing development of leydig and sertoli cells meaning there is testosterone and AMH present. this causes the development of wolffian ducts, testes and sperm
what do sertoli cells produce
AMH
what do leydig cells produce
testosterone
what does the external genitalia respond to in males
dehydroxytesterone
what coverts testosterone to DHT
5 alpha reductase
what occurs in gametogenesis (male)
- mitosis occurs at puberty onwards making spermatogonia type A and B
- meiosis then occurs - M1 makes the primary to secondary spermatocyte, M2 makes the secondary spermatocyte to the spermatid (M2 continuous after pruberty)
where do the spermatids mature in the males
they mature in the epididymis to spermatozoa
how long does the spermatids mature in the epididymis
64 days
what is the maturation process of spermatogonia to spermatozoa
spermatogonia B develops into primary spermatocyte. these then undergo M1 to make two secondary spermatocyte. M2 then happens and it makes 4x spermatids. these then develop into spermatozoa
what is the process of spermatids called spermatozoa called
spermiogenesis
what is the process of spermatogonia to spermatid called
spermatogenesis
what is the process of gametogenesis in females
- mitosis occurs at prebirth in the foetus to make primary oocytes.
- mitosis 1 then occurs to make secondary oocytes, and then M2 occurs to make oogonia.
in females when is M1 arrested until
until menarche - the 1st period
when does M2 occur in women
it occurs after fertilisation
what is the development from primary oocyte to oogonia
the primary oocyte undergoes M1 which becomes secondary oocyte and a polar body. the secondary oocyte M2 to produce oogonia and 3 polar bodies
what happens in puberty in women
primary development is by FHS and LH stimulating gonadotropins. secondary development is then caused by adrenal androgens
what is the path that sperm takes in the male reproductive system
Seminiferous tubules (spermatogenesis) - rete testis - efferent ducts - epididymis - vas deferens - ejaculation duct (joined by seminal vesicles) - (nothing) - urethra - penile urethra SREEVENUP
what is the pathway that the testes descends through
it descends through the inguinal canal by the processes vaginalis. It is covered in tunica vaginalis and fibrous capsule tunica albuginea
why are the testis found outside the body cavity
cooler - pampiniform plexus descends to exchange heat with the environment and cooler arterial blood to the testis
what makes up the blood testis barrier
sertioli cell tight junctions
what is the function of the blood testis barrier
to prevent an immune response to sperm and sperm movement into the systemic circulation
what is the female HPG axis
the hypothalamus releases GnRH, which then acts on the anterior pituitary to release FSH. this acts on the granulosa cells of the follicle and causes egg maturation.
Inhibitin inhibits FHS release. Oestrogen release acts to increase LH until it reaches threshold and there is an LH surge causing ovulation. The granulosa cells then become the corpus luteum and makes progesterone
what is the male HPG axis
GnRH from the hypothalamus then stimulates the anterior pituitary to make FSH and LH. FHS works on sertoli cells to make AMH, and LH works on the leydig cells to make testosterone. Sertoli cells make inhibin which acts on the anterior pituitary to reduce FSH.
testosterone acts on the sertoli cells to make sperm
testosterone is acted on by 5 alpha reductase to make DHT
what is DHT needed for in male development
external genitalia
where are androgens made in the adrenal glands
in the zona reticularis
what are the two stages of the menstrual cycle
follicular/proliferative and the luteal/secretory phases
what happens during the follicular phase of the menstrual cycle
there is follicular development and the womb lining proliferates
what happens during the luteal phase of the menstrual cycle
the oocyte is released and the follicle becomes the corpus luteum, in the womb lining there are large gaps in the structure with skinnier irregular tubes seen on H+E
where is GnRH made in the body
made in the hypothalamus
what are the effects of oestrogen production
increased LH (positive feedback), inhibition of FSH and it thickens the endometrium to prepare for ovulation
what happens to hormone levels if the oocyte is fertilised
then there is hCG produces as well as progesterone continually produced from the corpus luteum. oestogen also stays high
what happens if there is no fertilisation
then the corpus luteum breaks down and progesterone levels drop. this causes the womb lining to shed and the cycle then repeats
where does fertilisation occur
in the ampulla of the fallopian tube
what are the layers of the uterus
the endo, myo and perimetrium
what happens during labour
relaxin and oestrogen causes relaxation of the cervix. oxytosin then stimulates the uterine wall to contract
what happens on day 1 of fertilisation
there is the sperm acrosomal reaction at the zona pellucida which causes a calcium influx. this allows the sperm to fertilise the egg and the male and female pronuclei form. Syngamy occurs and the two nuclei combine to make a 2n nucleus
- fertilisation
what happens on day 2-3 after fertilisation
there is mitotic division 1-2-4-8 (these cells are totipotent)
- cleavage
what happens on day 4 after fertilisation
this is the 16 cell stage called a morula.
- compaction
what happens day 5 after fertilisation
the 32 cell stage, and the formation of the blastocyst. there is an inner cell mass formed called the epiblast, and an outer ring of cells called the trophoblast. the cells are pluripotent at this stage
- cantation
what happens day 6 after fertilisation
the zona pellucida is discarded which is key for fertilisation
- hatching
what happens 7 days after fertilisation
implantation of the blastocyst
what are the three stages of implantation
apposition = unstable binding attachment = stronger adhesion invasion = lacunar flow: uteroplacental circulation is established by the syncytotrophoblast and maternal sinusoids
what is the cell type found in the epididymis and the vas deferens
pseudostratified columnal with stereocilia
where is urothelium found
renal, pelvis, ureters, bladder and urethra (except penile)
what are the different layers of the skin
epidermis, dermis and subcutaneous tissue
what are the layers found in the epidermis of the skin
the stratum basale (deepest) the stratum spinosum the stratum granulosum the stratum lucidum the stratum corneum
what are the functions of the skin
barrier to infection, thermoregulation, protection against trauma, protection against UV, vitamin D synthesis and regulation of H2O loss
what are the membranes of the renal corpuscle like
they are fenestrated and negatively charged
what are the two layers of the bowmans capsule in the renal corpuscle
the basement membrane and the parietal epithelial cells
