Kidney Anatomy and Position

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Questions and Answers

What is the relative position of the right kidney compared to the left kidney?

The right kidney lies lower than the left kidney. (correct)

The right kidney is positioned posterior to the left kidney.

The right kidney is higher than the left kidney.

The right kidney is located to the left of the left kidney.

Which rib corresponds to the superior part of the left kidney?

10th rib

11th rib (correct)

9th rib

12th rib

At which spinal level does the hilum of the kidneys generally lie?

Transpyloric plane (correct)

What defines the posterior abdominal wall region where the kidneys are located?

T12-L3 Signup and view all the answers

Which of the following is NOT typically considered a retroperitoneal organ?

Spleen Signup and view all the answers

What is the external layer surrounding the kidneys called?

Renal capsule Signup and view all the answers

Which structure is responsible for the major calyx draining into the renal pelvis?

Minor calyx Signup and view all the answers

Which part of the nephron is located in the renal cortex?

Convoluted tubules Signup and view all the answers

What is the primary function of the renal medulla?

Reabsorption of water and nutrients Signup and view all the answers

Which artery is the first point of arterial supply to the kidneys?

Abdominal aorta Signup and view all the answers

Which location corresponds to the pelviureteric junction constriction?

At the apex of the renal pelvis Signup and view all the answers

What type of fat surrounds the kidneys, providing cushioning and protection?

Perinephric (perirenal) fat Signup and view all the answers

How many segmental arteries supply blood to the kidneys?

Five Signup and view all the answers

Which blood vessels supply the inferior part of the ureters?

Common iliac artery and inferior vesical artery Signup and view all the answers

What is the primary parasympathetic nerve innervating the kidneys and ureters?

Vagus nerve (CN X) Signup and view all the answers

Which lymph nodes are responsible for the lymphatic drainage of the superior part of the ureters?

Aortic/caval lymph nodes Signup and view all the answers

Which structure is NOT located on the superior surface of the bladder?

Prostate gland Signup and view all the answers

What is the main function of the detrusor muscles in the bladder?

Contract during urination Signup and view all the answers

Which region of the ureters receives blood supply from the abdominal aorta?

Middle Signup and view all the answers

What is the anatomical term for the area between the ureteric openings and the urethral opening in the bladder?

Trigone Signup and view all the answers

Which anatomical structures lie posterior to the bladder?

Seminal vesicles and ampulla of the ductus deferens Signup and view all the answers

What is the primary arterial supply of the bladder?

Superior vesical artery Signup and view all the answers

What is the primary function of the parasympathetic innervation to the bladder?

Relaxes the internal urethral sphincter Signup and view all the answers

Which structures drain lymphatic fluid from the fundus and neck of the bladder?

Internal iliac nodes Signup and view all the answers

Which part of the male urethra is most susceptible to injury during catheterization?

Membranous Signup and view all the answers

What is the venous drainage pattern for the female urethra?

Veins follow the arteries of the same name Signup and view all the answers

Which nerves provide the afferent fibers for reflex and pain sensation from the bladder?

Pelvic splanchnic nerves Signup and view all the answers

What is the primary function of the hypogastric plexus in relation to bladder function?

Inhibits the detrusor muscle Signup and view all the answers

The dorsal artery of the penis supplies which part of the male urethra?

Spongy Signup and view all the answers

Where do the internal pudendal artery and vaginal arteries primarily supply in females?

Urethra Signup and view all the answers

Which structure is part of the prostatic urethra?

Prostatic utricle Signup and view all the answers

Study Notes

### Kidney Position and Anatomy

Located on the posterior abdominal wall, between T12 and L3.
Right kidney is slightly lower than the left kidney.
Hilum: The point where vessels, nerves, and ureters enter and exit the kidney, located at the transverse plane 5cm from the midline.
Superior part:
- Left kidney: 11th rib
- Right kidney: 12th rib
Inferior part: Iliac crest

Kidney Internal and External Features

Renal capsule: A thin, fibrous membrane that surrounds the kidney, providing protection and support.
Perirenal fat: Surrounds the kidney to provide cushioning and insulation.
Renal fascia: A thick, fibrous membrane that surrounds the kidney and adrenal gland, attaching to the diaphragm superiorly and the psoas fascia laterally.
Paranephric fat: Surrounds the renal fascia and provides additional cushioning and insulation.
Cortex: The outer layer of the kidney, composed of:
- Cortical labyrinths: Contain renal corpuscles, convoluted tubules, and collecting tubules.
- Medullary rays: Contain straight tubules and collecting ducts.
- Ultrafiltration: This is where blood is filtered in the nephrons.
Medulla: The inner layer of the kidney, composed of:
- Medullary pyramids: Contain straight tubules, loops of Henle, and collecting ducts.
- Renal columns: Connect the cortex with the medulla and contain blood vessels and anchoring structures.
- Reabsorption: This is where water, nutrients, and electrolytes are reabsorbed back into the blood.
Renal papilla: The tip of the renal pyramid which drains urine into the minor calyx.
Minor calyx: A small funnel-shaped structure that collects urine from the renal papilla.
Major calyx: Formed by the fusion of minor calyces, which collect urine from multiple minor calyces.
Renal pelvis: A funnel-shaped structure that collects urine from the major calyces and sends it to the ureter.

Kidney Blood Supply and Lymphatic Drainage

Arterial Supply:
- Abdominal aorta (T12) to renal arteries (L1/L2 IVD)
- Renal arteries branch into 5 segmental arteries (superior, anterosuperior, anteroinferior, inferior, and posterior segments).
- Extrahilar arteries also contribute to the blood supply.
Venous Drainage:
- Segmental veins drain into renal veins, then to the inferior vena cava.
Lymphatic Drainage:
- Lymph vessels follow the renal arteries to aortic lymph nodes (para-aortic).

### Ureters

Course*
Start at the apex of the renal pelvis (L1).
Pass down the posterior abdominal wall.
Cross the transverse processes of the L vertebrae.
Travel anteroposterior to the bifurcation of the common iliac arteries.
Reach the ischial spine.
Finish at the posterosuperior angle of the bladder.
Constrictions*
There are three constrictions along the ureter's course:
- Pelviureteric junction
- Level of the common iliac arteries
- Entrance into the bladder

### Ureter Blood Supply and Lymph Drainage

Blood Supply: Supplied by branches from:
- Renal vessels
- Gonadal vessels
- [Abdominal aorta]
- Common iliac vessels
- Internal iliac vessels
Lymphatic Drainage:
- Superior: Aortic/caval lymph nodes
- Middle: Common iliac nodes
- Inferior (pelvic): External/internal iliac lymph nodes

### Bladder Anatomy

External Anatomy*
Hollow, strong muscular walls.
Apex: Superior edge of the pubic symphysis, attached by the median umbilical ligament.
Fundus: Opposite the apex.
Body: Between the apex and fundus.
Neck: Origin of the urethra.
Internal Anatomy*
Detrusor muscles: Forms the main body of the bladder wall.
Internal urethral sphincter: A smooth muscle sphincter that regulates urine flow passively.
Trigone: A triangular region at the bladder's base, with openings for the ureters and urethra.
Inter-ureteric torus: A ridge located between the ureteric openings.

### Bladder Relations

Superior: Peritoneum, small intestine, sigmoid colon
Posterior: Seminal vesicles, ampulla of the ductus deferens, rectovesical septum, rectovesical pouch, rectum (in males), uterus, uterine tubes & uterovesical pouch (in females).
Inferolateral: Pubic bones, pelvic floor, retropubic space (apex), prostate gland (neck in males).

### Bladder Blood Supply, Lymphatic Drainage, and Innervation

Arterial supply:
- Superior vesical artery (from anterior trunk of the internal iliac artery): Anterosuperior parts.
- Inferior vesical artery (in males) or Vaginal artery (in females): Fundus and neck.
Venous drainage: Vesical venous plexus drains into the inferior vesical vein, then internal iliac vein, and finally the internal vertebral venous plexus.
Lymphatic drainage:
- Superolateral: External iliac nodes
- Fundus and neck: Internal iliac nodes.
Innervation:
- Sympathetic: Hypogastric plexus (T11-L2/L3) via vesical plexuses.
- Inhibits the detrusor muscle (relaxation), contracts internal urethral sphincter, pain from superior surface.
- Parasympathetic: Pelvic splanchnic nerves (S2-S4).
- Motor to detrusor muscle (contraction), relaxes internal urethral sphincter, afferent (reflex and pain) fibres.

### Urethra

Females*
Straight tube: ~4cm long.
Origin: Internal urethral orifice in the bladder.
Course: Runs distally along anterior wall of vagina.
Opening: Vaginal vestibule at the external urethral orifice.
Males*
Intramural: Located within the neck of the bladder, near the internal urethral sphincter.
Prostatic: Runs through the prostate gland.
- Urethral crest: A longitudinal ridge in the prostatic urethra
- Prostatic sinuses: Lateral recesses along the urethral crest, containing prostatic ducts.
- Seminal colliculus: A small elevation that contains the prostatic utricle and the openings of the ejaculatory ducts.
Membranous: Passes through the perineal membrane, just inferior to the prostate gland.
- External urethral sphincter: A skeletal muscle sphincter that allows for voluntary control of urination.
Penile/Spongy: Runs through the corpus spongiosum, extending from the bulb of the penis to the external urethral orifice.
- Narrowest part of the urethra.
- Contains bulbourethral glands and the navicular fossa.

### Urethra Blood Supply, Lymphatic Drainage, and Innervation

Arterial supply:
- Males:
  - Prostatic branches of inferior vesical and middle rectal arteries (intramural, prostatic, membranous)
  - Dorsal artery of the penis (spongy)
- Females:
  - Internal pudendal artery
  - Vaginal arteries
Venous drainage: Veins follow the arteries of the same name.
Lymphatic drainage:
- Males:
  - Internal iliac lymph nodes (intramural, prostatic, membranous)
  - Deep inguinal lymph nodes (spongy)
- Females:
  - Internal iliac lymph nodes
Innervation:
- Females:
  - Vesical nerve plexus and pudendal nerve: Mixed sympathetic, parasympathetic, and visceral afferent fibers.
- Males:
  - Prostatic nerve plexus: Mixed sympathetic, parasympathetic, and visceral afferent fibers.
  - Dorsal nerve of the penis: Sensory innervation for the penis.

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Description

This quiz explores the anatomical position and features of the kidney, including its placement in the abdominal cavity and the protective layers surrounding it. Understanding these details is crucial for grasping the kidney's function and its relationship with surrounding structures.