Let's continue with the
bladder and the urethra.
So the bladder is going to receive
urine via the two ureters.
Urine is being produced by the kidneys, the
ureter have descending along the posterior
abdominal wall and then they're
going to enter into the bladder.
Now this view is of a male
bladder and actually we are looking at
it as if someone is standing behind me.
Someone standing behind me and looking
through my pelvis into the posterior
aspect of the bladder. And the posterior
aspect of the bladder has been opened up.
So what we can see here is the apex of the
bladder that's attaching to the anterior
abdominal wall. So the apex is attaching
to the anterior abdominal wall
just above the pubic symphysis.
We can see these nice muscular
detrusor muscle fibers forming the wall.
We can see the internal surface
of the bladder is elevated
into these rugae
allowing the bladder
to be distensible.
We can also see that we
have this smooth region
of the bladder and this
is known as the trigone.
This is kind of a triangular shaped area
that is flat and doesn't contain
these rugae and the detrusor muscle.
It doesn't really contract
and that's a good thing. As when the
bladder wants to eject the urine
the body of the bladder can
contract forcing urine out.
If the trigone contracted then the
urine within the bladder would just be
compressed it wouldn't been ejected.
At the apex, these two apices
of the trigone here and here
we see an opening for the two ureters
we see the ureteral orifice.
And then this trigone take
us down into the urethra
and here we can see the urethra.
Now in the male the urethra
passes through the prostate gland and
we can see the prostate gland
surrounding the urethra and this will
be the prostatic part of the urethra.
So we can see the bladder
is storing the urine
and then when its comes to being
ejected with micturition
so the urine passes through the urethra.
We can see on this diagram here,
the urine is going to pass through the urethra
which is at level of the prostrate
and then its going to
pass through the penis.
So we can see with the notes
now alongside the diagram
that the bladder has an apex.
It has a body, has a fundus
and then it take us down
into this neck here.
So we can see the neck of the bladder
here and we can see the trigone.
We can see the apex up
here. We can see a nice
body along the superior
surface and then the fundus
this posterior aspect of the bladder.
We can see we have got a nice detrusor muscle
allowing the muscle to constrict tightly.
It's got four surfaces, the bladder.
It's got this superior surface
and then its going to have
two inferolateral surfaces
that converge much like
a front of a boat.
The inferolateral surfaces that
converge and form the apex.
And then you have got the
superior surface here.
We will then find posteriorly, near
the fundus, this posterior surface.
The bladder neck, as I said, tapers and
we have found the urethra orifice
and urine passes through
this internal urethra orifice.
and it enters into the
prostatic part of urethra.
The internal urethral orifice
marks the beginning of the urethra.
And like I said this initially passes through the
prostrate. But it exits the pelvis by entering
into the base of the penis. And here
we can see we have various parts
of our urethra passing
through the penis.
We can see we have this what's called
intramural urethra or this preprostatic part.
That's just the portion by the neck of the
bladder before it's got into the prostrate.
We then have a prostatic urethra
which is important. As this is where
semen from the seminal
vesicles and sperms from the
testes can enter into
ureter for ejaculation.
So here we have
the prostatic urethra
We then have a portion of the
urethra called the membranous part
and this passes through
the pelvic diaphragm.
As it's leaving the pelvic
and entering the perineum
because the actual penis itself
is found within the perineum.
And urethra running through the
penis is known as the spongy urethra.
As it running through a rectal
tissue called corpus spongiosum.
So four parts to the penis.
A intramural or pre-prostatic part. A prostatic
part that runs through the prostate.
A membranous part that passes through
the pelvic diaphragm. And a spongy part
that runs through the corpus spongiosum.