The Renal System

2 Kidneys- Produces urine

2 Ureters

- transports urine

1 Urinary bladder

- stores urine

1 Urethra

- conducts urine

to outside

Renal Capsule- inner layer lines renal sinus

Adipose Capsule

- fat padding around kidney

Renal Fascia

- outermost layer

3 Layers Surrounding the Kidney

Transverse Section

Renal papilla

Outer renal cortex

Central renal

pyramid

Inner renal medulla

Renal pelvis

Minor calyx

Ureter

Major calyx

Calyx - singular

Calicies - plural

Calyx – ‘cup’

Pelvis = basin

There are 6-18 renal pyramids in a kidney:

- The renal papillae project into renal sinus.

Collection of Urine

Renal lobe

- Contains renal pyramid, overlying cortex, adjacent renal column.

Minor calyx

Major calyx

Renal Pelvis (continuous with ureter)

Renal Blood Supply

• Renal artery

• Segmental artery

• Interlobar artery

• Arcuate artery

• Afferent arteriole

Veins carry same names

• Interlobular artery

The Nephron

Loop of Henle (nephron loop)

Proximal convoluted tubule (PCT)

Distal convoluted tubule (DCT)

2. Renal Tubule

Bowman’s Space

Glomerulus

Bowman’s Capsule

1. Renal Corpuscle

The Nephron has 2 parts:

~85% Cortical NephronsShort loop of Henle.

Efferent arteriole

becomes peritubular

capillaries.

15% JuxtamedullaryCloser to medulla.

Loop of Henle deeper.

Efferent arteriole

becomes vasa recta.

Juxtaglomerular Apparatus

Macula Densa – specialized portion of DCT.

Juxtaglomerular (JG) Cells – specialized

cells, mostly surrounding afferent arteriole.

Sits in between afferent and efferent arteriole – for communication regarding renal function.

For changing diameter of afferent arteriole.

• Blood arrives at afferent arteriole.

Glomerulus – Fenestrated Capillary bed

• Blood departs via efferent arteriole.

Filtrate “filtered” at Glomerulus.

• Blood goes into a) Peritubular or

b) Vasa recta capillaries

• Blood exits via renal venule, vien.

The Nephron

• Actively reabsorbs– Nutrients (glucose, amino acids)– Ions– Small Plasma proteins

Proximal Convoluted Tubule

• Lined with simple cuboidal epi– With microvilli (brush border)– Large surface area

Descending limb

Ascending limb• Thin segment is simple squamous epi.• Thick segment is simple cuboidal epi (no nicrovilli)• For Water balance

Loop of Henle

Actively secretes ions and other materials

Distal Convoluted Tubule

Lined with simple cuboidal epi.

Lined with simple cuboidal epi.

Collecting Duct

Changes to simple columnar epithelium deeper in the medulla.

Bladder is lined with . . . Transitional epithelium