[1b] Tractus Urinaria 2003

7/29/2019 [1b] Tractus Urinaria 2003

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DEPARTEMEN ANATOMI

FK-USU

MEDAN

Tractus urinarius


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The urinary system of the human body consists of

two kidneys, two ureters, the bladder and a singleurethra.

The kidneys are located on the posterior wall of the

abdomen at waist level. Each kidney is roughly 10

cm long and 5 cm wide, and is encased in a fibrousouter capsule called the renal capsule.

The main function of the kidneys is to control blood

volume and composition. They do this by filtering

the blood to remove waste products, salts andwater. These are secreted in the form of urine.


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The kidneys are located in the posterior part of theabdomen.

There is one on each side of the spine ,the right kidneysits just below the liver, the left below the diaphragmaand adjacent to the spleen.

Above each kidney is an adrenal gland (also called the

suprarenal gland). The asymmetry within the abdominalcavity caused by the liver results in the right kidneybeing slightly lower than the left one while the left kidneyis located slightly more medial.

The kidneys are retroperitoneal and

They are approximately at the vertebral level T12 to L3. The upper parts of the kidneys are partially protected by

the eleventh and twelfth ribs.

Congenital absence of one or both kidneys, known as

unilateral or bilateral renal agenesis, can occur


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Ureter The ureters deliver urine to the bladder from the kidney to

bladder.

The ureters are retroperitoneal, which means that they are

located in the retroperitoneal space .

In adults the ureters are approx 12 inches (30 cm) long and have

a muscular coat that tightens and relaxes to move urine away

from the kidney. This muscular action is controlled by the

autonomic nervous system (ANS) and operates in a similar way

to that of peristalsis in the digestive system.

The ureters pass through the posterior surface of the bladder at

the Ureter Orifices.

Urine drains through the ureters directly into the bladderas there

are no sphincter muscles or valves at the ureter orifices


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Bladder

The bladder is located on the floor of the pelviccavity. (Other organs, glands and tissues located

in the pelvic cavity include the rectum, gender-

specific reproductive organs, parts of the small

intestine, blood vessels, lymphatic vessels, andnerves).

The bladder is located anterior to (i.e. in front of)

the rectum in males.

In females it is also in front of the uterus and

upper vagina so its location is described simply

as "anterior to the uterus and upper vagina".


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The urinary bladder is a musculomembranoussac whose shape is affected by factors including

the person's age and sex - as well as the volume

of urine it contains at the time.

The "superior" or "abdominal" surfaces, and the

"lateral" surfaces of the bladder are covered by

peritoneum.


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Bladder in pelvic cavity


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Structure of Bladder

The bladder itself ("musculomembranous sac") consists of 4

layers: Serous

The outer "serous" layer is a partial layer derived from theperitoneum.

MuscularThe detrusor muscle is the muscle of the urinary bladderwall.It consists of three layers of smooth (involuntary) musclefibres. The external layer is longitudinal, the middle layer iscircular configuration, and the internal layer is longitudinal .

Sub-mucous

This is a thin layer of areolar tissue . Mucous

The innermost layer,which contains transitional epitheliumtissue that can stretch. The ability of this tissue to stretch isimportant because it contains variable volumes of liquid - as

the bladder is filled and emptied several times per day.Because it is only loosely attached to the (strong and


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Female urethra

At only about 1.5 inches (35 mm) long, the female adult

urethra is shorter than the adult male urethra (approx. or

8 inches, or 200mm).

The female urethra is located immediately behind the

pubic symphysis and is embedded into the front wall of

the vagina.

The urethra itself is a narrow membranous canal that

consists of three layers:

Muscular layer- continuous with the muscular layer of

the bladder, this extends the full length of the urethra.

Thin layer of spongy erectile tissue - including

plexus of veins and bundles of smooth muscle fibres.

Located immediately below the mucous layer.


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Mucous layer- internally continuous with thebladder and lined with laminated epithelium that is

transitional near to the bladder.

After passing through the urogenital diaphragm ,the

female urethra ends at the external orifice ofurethra - which is the point at which the urine leaves

the body. This is located between the clitoris and the

vaginal opening.

The passage of urine along the urethra through theurogenital diaphragm is controlled by the external

urethral sphincter, which is a circular muscle under

voluntary control (that is, it is innervated by the

somatic nervous system, SNS


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Male urethra

At about 8-9 inches (200 mm) long, the adultmale urethra is longer than the adult female

urethra (of approx. 1.5 inches 35 mm).

It has three portions (the pros tat ic u rethra, the

membranous urethra, and the spon gy urethra)and extends from the neck of the bladder to the

meatus urinarius at the end of the male

penis/urethra.


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The three regions/sections of the male urethra are:

Prostatic UrethraThe prostatic urethra begins at the neck of the bladder

and includes all of the section that passes through theprostrate gland. It is the widest and most dilatable partof the male urethral canal.

Membranous Urethra

The membranous urethra is the shortest and narrowestpart of the male urethra. This section measures approx.0.5 - 0.75 inches (12 - 19 mm) in length and is thesection of the urethra that passes through the maleurogenital diaphragm.The external urethral sphincter(muscle) is located in

the urogenital diaphragm (as for the female urethra).The passage of urine along the urethra through theurogenital diaphragm is controlled by the externalurethral sphincter, which is a circular muscle undervoluntary control (that is, it is innervated by the somatic

nervous system, SNS).


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Spongy Urethra The spongy urethra is the longest of the three

sections.

It is approx. 6 inches (150 mm) in length

It is contained in the corpus spongiosum thatextends from the end of the membranous portion,

passes through the penis, and terminates at the

external orifice of the urethra - which is the point

at which the urine leaves the body.


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Thank you

[1b] Tractus Urinaria 2003

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