Kidney to Bladder

The two upper urinary tract organs are…

1. Kidneys

2. Ureters

The two lower urinary tract organs are…

1. Bladder

2. Urethra

Give main characteristics of the kidneys

• They are bilateral bean-shaped organs, reddish-brown in Color, and surrounded by smooth fibrous capsule

• Between 5th and 9th week of gestation, the kidneys typically ascend from the pelvis to a position high on the posterior abdominal wall (typically extend from T12-L3)

• Right kidney is often lower due to liver

• Retroperitoneal

• Surrounded by perinephric fat which extends into the renal sinuses

Which two nerves run posterior to the kidneys?

1. Iliohypogastric nerve

2. Ilioinguinal nerve

_______________ sit atop each kidney. What do they do?

Suprarenal / Adrenal Glands

• Release catecholamines and steroids

• Plays a role in blood pressure regulation

• Function as part of the endocrine system, completely separate in function from the kidneys

• Separated by the kidneys by fascial septum

Name and describe the parts of the kidney

1. Hilum/Hilus : area where vessels, lymphatics, and nerves enter and leave the kidneys; continuous with renal sinus

2. Renal cortex: continuous band of pale tissue that completely surrounds the renal medulla

3. Renal medulla: between the renal cortex and renal sinus

4. Renal sinus: area between the renal medulla and pelvis/hilum

5. Renal columns: internal extensions of the renal cortex — divides the renal medulla into renal pyramids

6. Renal papilla: apical openings of the pyramids projecting into the renal sinus

7. Minor calyx: receive urine from the papillary ducts (contained in renal papilla)

8. Major calyx: when 2-3 minor calyx unite

9. Renal pelvis: when 2-3 major calyx unite → ureter

Identify

1. Renal column

2. Renal column

3. Major calyx

4. Renal artery

5. Hilum

6. Renal vein

7. Renal pelvis

8. Ureter

9. Minor calyx

10. Renal sinus

11. Renal papilla

12. Renal cortex

13. Renal pyramid

The _______ artery carry unfiltered blood into the kidney: it is a lateral branch of the __________ that usually arise just _______ to the origin of the SMA. The left artery is ______ and originates _______ than right artery. The right artery is ______ and passes _________ to the inferior vena cava. Tha arteries are _________ to the veins.

Renal, abdominal aorta, inferior, shorter, higher, longer, posterior, posterior

The _______ veins carry filtered blood out of the kidneys; they are formed by many smaller veins at the ______. They are ________ to the renal arteries; the left vein is _________ than the right, crosses ________ to the abdominal aorta and __________ to the SMA.

Renal, Hilum, anterior, longer, anterior, posterior

The kidneys receive _______% of the cardiac output of blood

20-25

Identify

1. Inferior vena cava

2. Right renal artery

3. Right renal vein

4. Abdominal aorta

5. Left renal vein

6. Left renal artery

7. Superior Mesenteric Artery

What are the 3 main functions of the kidneys? Describe each one slightly (covered more in physiology)

1. Produces urine — excretion of waste, excess medicine, organic materials

2. Filters blood — most of the contents of the blood goes back to the bloodstream, some is excreted as urine

3. Regulates aspects of homeostasis: blood pressure, water balance, balancing of electrolytes, acid-base balance, RBC production, activation of vitamin D

• Essential to clear bacterial components and cytokines from the blood

What are nephrons? (answer very general, again covered in physiology)

They are the functional unit of the kidneys

• 1-2 million in each kidney

• Important in filtration, reabsorption, and secretion

• Starts in the cortex and loops down into medulla

What is defined as a kidney lobe?

Renal pyramid + surrounding cortical tissue

Cortical nephrons are primarily responsible for ___________ whereas juxtamedullary nephrons are primarily responsible for ____________.

Excretion and regulation, concentrating and diluting urine

Define and describe (generally) what a glomerulus is

The filtering unit of the kidney

• A unique bundle of capillaries lined by delicate fenestrated endothelia, a complex mesh of protein that serve as the glomerular basement membrane, and specialized cells that form the slit diaphragms between interdigitating foot processes

• Enclosed in the renal corpuscular capsule, or Bowman’s capsule

What are juxtaglomerular cells?

Cells located in the walls of the afferenr arterioles, that act as baroreceptors, sensing changes in blood pressure, and respond to low BP, low salt diets, and sympathetic stimulation

Ureters are _____peritoneal muscular tubes that transport urine from the ________ to the _______. They are about 25cm long, and 3 mm thick. They are made up of _______ muscle arranged in spiral, longitudinal, and circular bundles

Retro, kidneys, bladder, smooth

The renal pelvis becomes continuous with the ureter at the ______________. The ureter then descends onto the antero-medial aspect of the _________, then cross anteriorly over the ____________, at the division of _________ and _________ to enter the pelvic cavity. The ureter then enters on the postero-lateral wall of the _______

Ureteropelvic junction, psoas major, common iliac artery, external and internal iliac arteries, bladder

How does urine go from the kidneys to the bladder (I.e. what happens)

An increase in pressure (in the kidneys) initiates a peristaltic contraction beginning in the pelvis and spreading downward along the ureter to force urine toward the bladder

What arteries provide blood supply to the ureters?

1. Renal arteries — upper part

2. Gonadal and common iliac arteries — middle part

3. Branches of the internal iliac arteries — lower part

Give characteristics of the bladder, in general

• Is the most anterior element of the pelvic viscera

• Sub/Infra peritoneal

• Shaped like a 3 sided pyramid that has tipped over to lie on one of its margins

• Becomes a pelvic organ after puberty — in the newborn, it’s small and cannot concentrate urine

• Hollow, muscular organ that stores urine

• Expels urine through the urethra

Describe the anatomy of the bladder

1. Rugae: folds in the wall of the bladder when it is empty; allows for expansion (they disappear as it expands)

2. Has 4 layers: mucous coat, sub-mucous coat, muscular coat (contains transitional epithelium and detrusor muscle), and serous coat)

3. Detrusor muscle: interlaced smooth muscle fibers of the muscular coat — forms the internal urethral sphincter, innervated by parasympathetic fibers (that causes contraction)

T/F:

1. The cellular thickness of the bladder changes based on how much urine it holds

2. The bladder most often holds about 1L of urine before the need to urinate (micturition) emerges

1. True

2. False → it may hold up to 1L of urine, but the urge to urinate occurs once it contains 200mL (in adults, the normal urge to urinate usually occurs as the bladder exceeds 500 mL)

What nerves innervate the detrusor muscle?

S2-S4 parasympathetic fibers via the pelvic splanchnic nerves

What is the trigone?

An area of increased sensitivity to stretch

• Triangle formed by two ureteral openings and internal urethral sphincter

Give some differences between the external and internal urethral sphincters

1. Location: internal is at base of the trigone/bladder, external is in the deep perineal space of the urogenital diaphragm

2. Muscle type: internal is smooth muscle (involuntary), external is striated muscle (voluntary)

3. Innervation: sympathetic innervation for internal, autonomic innervation (pudendal nerve S2-4) for external

Identify

1. Detrusor muscle

2. Body of the bladder

3. (Urothelium) Rugae

4. Ureteral opening

5. Trigone

6. Urethral opening

7. Bladder neck

8. Internal Urethral Sphincter

9. Urethra

10. External Urethral Sphincter

Identify

1. Detrusor muscle

2. Body of the bladder

3. (Urothelium) Rugae

4. Ureteral opening

5. Trigone

6. Urethral opening

7. Bladder neck

8. Internal Urethral Sphincter

9. Urethra

10. External Urethral Sphincter

Identify

1. Rectum

2. Uterus

3. Vagina

4. Urinary bladder

Identify

1. Urinary bladder

2. Rectum

3. Prostate gland

What artery/ies provide the primary and supplementary supply of blood to the female bladder ?

Primary: superior vesical artery (from internal iliac (anterior trunk) → umbilical →)

Supplementary: vaginal artery, obturator artery, inferior gluteal artery

What artery/ies provide the primary and supplementary supply of blood to the female bladder ?

Same as female, but vaginal artery → inferior vesical artery

Describe the innervation of the bladder

Pelvic splanchnic nerves primarily relay somatic sensory information regarding bladder wall stretch

• Parasympathetic Fibers :

  • S2-S4 spinal cord via the pelvic splanchnic nerves and inferior hypogastric plexus

  • Provide MOTOR innervation the the detrusor muscle = promotes contraction of the detrusor muscle

  • Inhibit contraction of the internal urethral sphincter

• Sympathetic Fibers:

  • Conveyed from lower thoracic and upper lumbar spinal cord via the sacral splanchnic nerve to the hypogastric plexus and nerves

  • Promotes contraction of the internal urethral sphincter

  • Helps inhibit detrusor contraction during early filing phase