Topic 18: Vertebrate Systems Development-5 Reproductive Systems

Both the excretory and reproductive systems are derived from?

intermediate mesoderm

Because the excretory and reproductive systems are derived from intermediate mesoderm, both systems are ( )

primitively segmental

Most preconceived notions about kidneys, their shape, and origin are colored by the ( ) condition

mammalian

Recall that those vertebrates that retain the entire kidney derived from every body segment are said to have a ( ) or ( )

holonephros

“holonephric” kidney

Primitively/initially, there is an intermediate mesoderm segment, and thus ( ). Few vertebrates still retain such a long kidney

kidney or gonad segment for every body segment

Only the most primitive remaining vertebrates have a ( )

holonephros

the cranial-most part of the kidney, the ( ) develops first, but is subsequently lost. However, it is critically important, because it induces the development of the more caudal segments of the kidney

pronephros

The remaining portion of the kidney is the, excluding the pronephros, is the ( ). This is found in many fishes, and some amphibians

opistonephros

cool

Gonadal materials develop in a ridge that is also derived from ( ), and runs roughly parallel to the ( )

intermediate mesoderm

nephric ridge

The reason we didn’t see gonadal materials prior was because the ( ) expresses only in the ( )

gonadal ridge

more caudal/posterior region of the body

cranial to middle part of the body

more caudal region of the body

In a male, the ( ) are still draining from the anterior/cranial end of the ( ) to the ( )

renal tubules

opistonephros

archinephric duct

what is the archinephric duct also known as?

the mesonephric duct

Testes attach to the anterior/cranial end of the ( ) via ( ) and ( )

archinephric duct

rete testes

vasa efferentia

Once the testes attach to the archinephric duct via rete testes and vasa efferentia, the ( ) is essentially taken over by the ( ) for ( ) and is now known as the ( ) or the ( )

archinephric/mesonephric dust

gonad

sperm transport

ductus deferens

vas deferens

The archinephric/mesonephric duct has essentially been co-opted/taken over by the ( ). As this happens, the ( ) regresses

testes

mesonephros

As the mesonephric duct is being taken over by the testes, the ureter is only draining the ( )

posterior/metanephric kidney

label and draw

label and draw

Note how testes take over mesonephric duct in males

okay

The condition in females is similar in pretty much all ( ), from ( ) to ( )

gnathostomes

fish

amniotes

In females, there is no battle for the ( ). In females, the ( ) leave the ( ) duct to the kidney, and ( )

duct

ovaries

mesonephric/archinephric

build their own duct

In females, the ( ) still grows forward toward the ( )

ureter

metanephros

females do not take over the ( ), but rather, build their own, separate ( )

mesonephric duct

oviduct

The end of the oviduct does not insert into the ( ) . It is just a ( ). Elaborated edges of the funnel are called ( )

ovary

funnel

fimbria

Note how ovaries do not take over mesonephric duct in females

yes

The metanephric kidney forms from the ( )-most kidney segments, but mammalian kidneys actuall move ( )

caudal

cranially (the term “ascent” is used in orthograde humans)

What is the mechanism to kidney movement in mammals?

The mechanism of this is not perfectly understood. Some researchers say that kidneys actively move cranially, whereas other suggest they stay in place and the body grows and expands past them

How do kidneys move?

They do so by attaching successively to more cranial segmental arteries, while simultaneously detaching from more caudal segmental arteries (sorta like climbing a ladder)

The final connecting arteries of the kidney are the paired

Renal arteries

As the kidneys attach to successively more cranial segmental arteries, the ureters stretch to retain their connections to the ( ), and the ( )

metanephric kidney cranially

bladder caudally

kindeys “ascend” to just caudal to ( ) and ( )

diaphram

liver

the ( ) kidney is a bit lower due to ( )

right

mass of liver

Kidneys and gonads pass one-another, so the ( ) and ( ) in males must cross one-another

ureter

ductus deferens

the ( ) and ( ) pass ( ) to the ureter

gonadal arteries

ductus deferens

ventral

The gonads start development near the ( ) but you will recall mammalian gonads are not in the ( )

mesonephric kidney

middle of the body

Mammalian gonads actually move ( )

caudally ( the term “descent” is used in orthograde humans)

The gonads follow a tract of ( ) called the ( ) into a more ( ) position. Near the ( ) of the ( ) in females, ( ) in males

connective tissue ( some liken it to a slide)

gubernaculum

caudal position

brim cranial edge

pelvic girdle

all the way out of the body

As the gonads move more caudally, they do not attach and detach from successively more ( ) . Rather, the paired ( ) stretch and remain connected ( ). Thus, ( )

caudal segmental arteries

gonadal arteries

near where they started

gonadal arteries are often quite long and sometimes connected to the nearby renal arteries

In males, the ( ) tear right through the body wall to reside in their own separate sac, the ( ). As they do this, they take with them equivalents to all the ( ) with them as the ( )

testes

scrotum

body wall layers

scrotum is built

There will be a thin/tiny layer of all body wall parts equivalent to the ( ) and a tiny bit of coelom in each side of the ( ) . Called the ( )

scrotum

scrotal sac

tunica vaginalis

woah

woah

In females, erectile tissue is ( ), the ( ) do not fuse in the midline and do not enlarge as much

present

bulbs

The bulbs of the vestibule form separate masses of ( ) on either side of the ( )

erectile tissue

vaginal opening

The bulbs of ( ) will become the ( ) , singular ( )

the vestibule

labia minora

minorum

Because the bulbs of the vestibule dont fuse in the midline, the female ( ) cannot be enclosed in the midline as in the ( ) of the male

urethra

corpora spongiosa

The tip end of the midline columns is the ( ). Right and left ( ) form ( ) of clitoris

clitoris ( similarly sensitive to glans of males)

crura

(much smaller) corpora cavernosa

okay

where is the clitoris, labia majorum and minorum (3 total)

males have ( ) of erectile tissue

three columns

The right and left bulbs fuse in the midline to form the ( ) which ( )

corpora spongiosum

surrounds the urethra

In males, the urethra emerges out of tip of enlarged genital tubercle- the ( )

glans of the penis

In males, at the tip of the ( ) that is the ( )

bulbous dilation

glans of the penis

In males, right and left ( ) remain independent and form the paired ( )

crura

corpora cavernosa

The right and left sides of the penis are bound to one another by what?

tunica albuginea