Urogenital System Flashcards
urinary system
kidneys and ducts that transport urine out of the body
reproductive system
gonads and ducts which carry eggs or sperm away
role of kidneys
water balance, collection and excretion of (nitrogen) waste, and salt balance
uriniferous tubule
comprised of nephron and collecting tube
blood brought into kidney via renal arteries and flows into glomerulus (capillaries)
blood filtered at renal capsule
blood leaves kidneys through renal vein
nephron
proximate, intermediate, and distal tubules where filtrate passes through
filtrate composition altered during transport as water and nutrients are removed
intermediate nephron is expanded in mammals to become loop of henle
collecting tube
where filtrate empties
human kidneys
cortex (nephrons) and medulla (collecting duct and loop of henle) regions
urine produces flows into minor calyx, major calyx and collects in renal pelvis that connects to the bladder via the ureter
Homeostatsis
constant or near constant internal environment
Ammonotelism
is direct excretion of ammonia (in majority of fish)
flushed out in aquatic animals that live in water
has high solubility,water loss, toxicity, and low energy cost
uricotelism
excretion of uric acid (in reptiles and birds)
kidneys form uric acid that mixes with salts that are excreted
low water solubility, water loss and toxicity, but requires lots of chemical energy
ureotelism
excretion of urea (in mammals)
kidneys convert ammonia into concentrated urea, water content can be modified
medium water solubility, water loss, and toxicity, but high energy cost
variation in nitrogen elimination
lungfish can excrete ammonia when in water but also as urea during dry season
alligators can excrete ammonia or uric acid
turtles can excrete all thee forms of nitrogen
osmoregulation and osmolarity
homeostatic regulatory mechanism used to maintain the concentration of water and ions in the body
osmolarity is total solute concentration
fresh water vs saltwater fish osmoregualtion
freshwater fish are hypersomotic and can overhydrate
saltwater fish are hypoosmotic and can dehydrate
mass filtration
allows water loss, expunge water from system
filtration between glomerulus and renal capsule
filtration in renal corpuscle
fluid and small solutes are pushed through pores over GBM and podocytes
larger molecules remain the the cell
blood pressure provides force (renal arteries for aorta)
nephrons of freshwater fish
distal tubule removes important nutrients from filtrate
most of the water is left
nephrons of saltwater fish
remove glomerulus and renal capsule, reduce initial amount of filtrate, lost distal tube allowing greater water retention
conserving water on land
filtration is not selective
reabsorption is selective and highly regulated by a loop of Henle, resulting in concentrated urine
mammalian proximal tubule
blood is filtered through glomerulus and renal capsule
proximal tubule is where salt, nutrients, and water are reabsorbed, proximal tubule epithelium is covered in microvilli (greater absorption)
loop of henle
elongated loop is used to create osmotic gradient in medulla of kidney
Na pumped out creating gradient osmotic pressure for water to flow in
filtrate flows through collecting duct is reabsorbed due to gradient (greater osmolarity)
mammalian nephron
distal tubule incorporated into loop of henle to absorb more salt
hormones control water permeability in distal tubule and collecting duct
when dehydtated water moves across the membrane and reabsorbed (leaves tubule)
when hydrated membrane is made impermeable to allow water to be expelled (won’t leave tubule)
salt glands
tetrapods that spend a lot of time in saltwater excrete salt through salt glands instead of kidneys
sharks as osmoconformers
sharks keep their blood osmolarity near seawater
keep higher amounts of urea in blood making it isotonic
Different solutes in blood and seawater but same osmolarity
3 types of kidneys in verebrates
pronephros: found in larval forms and some adult fish
mesonephros: found in most fish and amphibians
metanephros: found in amniotes
holonephrons
separate parts of one kidney
gastrulation
process that creates the initial gut of animal
neutrulation
process of forming the initial neural tube coincides with gastrulation
3 layers of germ layer
ectoderm, mesoderm, and endoderm
where does the urogenital system form
urogenital ridge from the mesoderm in a position dorsal to the coelom (coelom is body cavity between alimentary canal and body wall)
nephric and genital ridges rise from the urogenital ridge
development of uriniferous tubules
nephric tubules are formed within nephritic ridge
tubule appear in 1/3 places (pronephrons, mesonephros, and metanephros) this is basis for tripartite concept
ducts of nephric tubules
pronephros connection to the pronephric duct
mesonephros coopt and rename mesonephric duct
archinephric duct is the general name for duct
metanephros use metanephric however the other tubules and associated ducts do form
reproductive ducts
if gonads produce sperm archinephric ducts become vas deferens that carry sperm to the urethra
if gonads produce ova mullerian duct arises next to the archinephric duct become basis of oviduct
segmented oviduct
funnel: collects eggs from ovaries
shell gland: secretes albumen and mucus
isthmus: connects shell gland to uterus
uterus: gives nutrients to egg while held
oviducts in amniotes
archinephric duct is reduced/lost
metanephric kidneys are emptied by ureter
oviducts carry eggs
shell gland add shells to eggs that will be laid outside body (reptiles and birds)
oviducts in mammals
fallopian tubes is oviduct between ovaries and uterus
uterus is formed by joining of two oviducts into single chamber that leads to vagina (houses embryo)
nutrients and oxygen are shared with embryo via placenta
opossums vaginal system
uterus empties into vaginal sinus which splits into 2 lateral vaginas
lateral vaginas reconnect at the urogenital sinus
kangaroo vaginal system
lateral vaginas are joined by central vaginal canal at the urogenital sinus
vagina variation in other mammals
oviducts (fallopian tubes) empty into uterus that connects to single vagina
uterus may have several configurations:
duplex: 2 separate uteri
bipartite: partial fused uteri
bicornuate: more fused
simplex: single uterus chamber (humans)
3 compartments of cloaca
coprodeum: connected to intestines
urodeum: connected to bladder
proctodeum: connected to genitals, this is where external genitals form
cloaca repoductive ducts
oviduct has separate opening into cloaca from urinary system (genital and urinary papilla)
vas deferens joins urinary tract into common one (urogenital papilla)
placental mammals cloaca
coprodeum –>rectum
urodeum –> urethra
proctodeum –> vagina
if vas deferens instead, proctodeum is urethra
pleiotrophy
when one gene has a wide influence over anatomical form
homeotic genes are an example that control a host of secondary genes that are responsible for building parts of anatomy
Hox genes
subtype of homeotic gene that specifies regions of an embryo, determine where leg is created
cells need something to tell them what to be
knock out genes
prevents the gene from doing its job during development to see what results are (named after what it lacks)
abnormalities and Mullerian ducts
agenesis: absence of body part
atresia: opening or passage of tract closed
septation: additional partitions within the organ
Formation of Mullerian duct
forms parallel to the Wolffian duct
Mullerian formation in mice-knockout genes
Pax 2: adult lack kidneys or reproductive tract
Lim1: adults lack uterus/vagina or vas deferens
Emc2: adults lack kidneys and reproductive organs
Wnt family: no oviducts formed
Mullerian formation problems in humans: HNF1B and MKKS
HNF1B: mutations in this gene cause maturity onset diabetes of the young, may cuase mullerian or vaginal aplasia
MKKS: McKusick- Kaufman syndrome, causes malformation of Mullerian ducts created blockages in vagina and leading to a build up of fluid in the pelvis (Hydrometrocolpos)
Mullerian inhibiting substance (MIS)
prompts Mullerian regression
if testes form without it ovaries and uterus will also form
if ova forms but MIS is expressed, Mullerian ducts and derivatives will not develop
Persistent Mullerian duct syndrome (PMDS)
rare recessive condition where testes are present and functional and Mullerian duct tissue remain
Hand-foot genital syndrome
autosomal dominant disorder
symptoms include shortened thumbs and big toes
initial pair of gonads
neither testis nor ovaries- indifferent gonads
germ cells in gonads
form outside of embryo itself and travel inwards to enter the gonads
germ cells medulla vs cortex
it they enter medulla they expand to form the testis cords
if they enter the cortex they form follicies leading to vary development
testis and vas deferens
testis surrounded by tunica albuginea
coiled seminiferous tubules within testis create sperm
tubules straighten into tubuli recti before joining rete testis
sperm travels to efferent ductules into epididymis (where stored)
smooth muscle pushed sperm into vas deferens (during ejaculation) until reaching urethra
3 glands that add fluid to sperm
seminal vesicle: adds thick, fructose secretion
prostate: adds alkaline material to protect sperm from acidity in the urinary tract
bulbourethral: adds mucus
fluid and sperm is semen
layers of oviduct
tunica albuginea: outer connective tissue
cortex ( has ova)
medulla
follicle
ova and associated follicle cells
ova wrapped in layers of follicle derived from connective tissue
ovulation and menstruation
ovulation: mature ova released from ovary
ova moves though oviduct into uterus
menstruation: ova flushed out
internal fertilization
eggs remain in uterus or embryo is evtually sealed in calcareous egg, sperm deposited into oviduct and travels up to fertilize egg (copulation)
external fertilization
sperm and eggs released into the water
intromittent organ
used to achieve copulation by momentary apposition of cloaca
pelvic claspers in chondrichthyans
gonopodium in teleost
hemipenis in lizards and snakes
spermatophore
the cap of sperm on the top of gelatinous pedestal, the male leaves it in front of the female, and the receptive female will nip the top with her cloaca
hemotumescence, evagination and invagination
h: muscle action and blood infiltration during erection
e: hemipenis moves outside the cloaca and turns inside out
i: retractor muscles pull hemipenis back in and outside in again
sulcus spermaticus
sperm runs along this outer groove of hemipenis
corpora cavernosa and sulcus spermaticus (turtles)
cc: two bands of tissue in penis
ss: groove in between two bands of tissue
mammal penis
composed of copora cavenosa, corpus spongiosum surrounds sulcus turning it into tube (cavernous urethra)
(in some) baculum bone located in connective tissue to aid in stiffness
blood flow of penis
during erection nerve stimulation cause increased blood flow in internal pudendal artery
inhibition of blood flow back into the internal pudendal vein
sexual conflict
evolutionary interests of sexes differ, males and females want different outcome of copulation
female sperm storage (FSS)
(in vertebrate with internal fertilization) females have capacity to store sperm
FSS structures
birds have sperm storage tubules invagination (cavity) along utero vaginal junction (UVJ)
Female cryptic choice and sexual conflict in gartner snakes
once female gives off pheromones males for mating ball around females
females can store sperm and selectively use the sperm later
males prevent other from gaining sperm by copulatory plugs that acts a spermatophore that prevent other males copulation
case study of garter snakes
males and females are in sexual conflict arms race
copulation time determined by the size of the copulatory plug left by the male
duck copulation experiment
ducks stimulated to evert into tubes mimicking different shaped vaginas
male organ cannot successful evert into glass tubes shaped like female vagina
when with a preffered male female can contract and relax muscles to allow for male to evert
