4. Kidneys, Ureters, Suprarenal Glands

Functions of kidneys

- Erythropoietin synthesis

- Renin synthesis

- Vit D activation

What surrounds the kidney?

Perirenal fat capsule

Level of L & R kidney

L: T12-L3

R: Slightly lower

What muscle is inferior to the kidney?

Quadratus lumborum muscle

Renal hilum

Entrance/exit for neuromuscular structures and ureter

Renal sinus

Space filled with fat, branches of vasculature, urine collecting structures

Renal capsule

- Tough fibrous layer

- Within perirenal fat

Structures within the renal cortex

Contains renal corpuscles, proximal / distal tubules, proximal collecting ducts

Renal column

Cortex between renal pyramids

Structures within the renal medulla/pyramids

Loop of Henle and distal collecting tubules

Function of renal medulla/pyramids

Drainage to calyces

Function of calyces

Collect urine from collecting ducts

Flow from renal pyramid to renal pelvis

1 pyramid → 1 minor calyx

2-3 minor calices → major calyx

2-3 major calices → renal pelvis

Structures of nephron

- Renal corpuscle

- Renal tubules

- Collecting duct system

Structures of the renal corpuscle

Bowman's capsule and glomerulus

Structures of the renal tubules

Proximal convoluted tubule, loop of henle, distal convoluted tubule

3 processes of urine formation within nephron

1. Filtration through glomerulus

2. Reabsorption

3. Secretion solutes into tubules

How much blood does the kidney filter a day? How much urine is produced?

180 L/day → 1.5 L urine

Blood flow from aorta to IVC

Aorta → renal artery → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries → renal vein → IVC

General blood supply to kidney

Each artery supplying nephron has 2 capillary systems: 1 within renal corpuscle and 1 surrounding tubular/collecting duct portion of nephron

What surrounds the adrenal glands?

Connective tissue and fat

What does the adrenal cortex secrete?

- Corticosteroids

- Mineralocorticoids

- Sex hormones (androgens, estrogens)

What does the adrenal medulla secrete?

- Epinephrine

- Norepinephrine

Length of ureter

25-30 cm

Peristalsis of ureter is controlled by...

Internal pacemaker via sympathetic OR parasympathetic

Location of the ureter

Descends peritoneal to cross pelvic brim at bifurcation of common iliac vessels

3 sites of ureter where kidney stones commonly get stuck/cause pain

- Renal pelvis and ureter junction

- Ureter crossing pelvic brim

- Ureter cross wall of urinary bladder

Layers of the ureter (superficial to deep)

1. Tunica adventia

2. Muscular

3. Mucosa

Composition of mucosa layer of ureter (2)

- Epithelium

- Lamina propria

Composition of muscular layer of ureter (2)

- Circular muscle

- Longitudinal muscle

Composition of tunica adventia layer of ureter (2)

- Connective tissue

- Adipose

The branches of the renal arteries branch off of the...

Abdominal aorta

Level of renal arteries branching off the abdominal aorta

L1-L2 (just below SMA)

Right renal artery in relation to IVC

Posterior to the IVC

The renal arteries divide into...

5 segmental arteries

Blood supply with kidney ascending during development

Common iliac → distal aorta → abdominal aorta

Kidney transplants

Placed lower in abdomen, attached to common iliac vessels (and leave diseased kidney)

Location of renal veins

Anterior to renal arteries, passes between SMA and aorta

Where do the renal veins drain into?

IVC

Difference between L and R renal veins

Left is longer!

Which veins drain into the L renal vein?

Left suprarenal and left gonadal vein

Arterial supply of the ureters (4)

- Renal arteries

- Aorta

- Gonadal arteries

- Iliac arteries

Where does the venous drainage of the ureters drain into?

Renal and gonadal veins

Blood supply of suprarenal glands (+ where the arteries branch from)

- Superior suprarenal a. — from inferior phrenic a.

- Middle suprarenal a. — from aorta

- Inferior suprarenal a. — from renal a.

Drainage of L and R suprarenal veins

R: Into IVC

L: Into L renal vein

Innervation of kidneys

Sympathetic: Least splanchnic nn. (pain = T12-L2 dermatomes)

Pregang: Aorticorenal ganglia

Parasympathetic: Vagus

Innervation of suprarenal glands

- Greater splanchnic nn.

- Presynaptic fibers travel with paravertebral and aortic ganglia → direct synapse on chromaffin cells of suprarenal medulla

Innervation of abdominal ureters

Renal, abdominal aortic, superior hypogastric plexuses

What is responsible for pain of the ureter? Location?

- Visceral afferents of sympathetics to T11-L2

- Ipsilateral LQ and groin

Attachments of quadratus lumborum

Transverse process of L5, iliac crest, iliolumbar ligament & transverse process of L1-L4 and rib 12

Function of quadratus lumborum

- Stabilizes rib 12 with diaphragmatic contraction w/ inspiration

- Unilateral bending of trunk

Blood supply of quadratus lumborum

Lumbar arteries

Innervation of quadratus lumborum

T12-L4

Attachments of psoas major

T12-L5 vertebral bodies/TPs/discs & lesser trochanter of femur

Function of psoas major

- Flex thigh at hip

- Flex vertebral column

Blood supply of psoas major

Lumbar and iliolumbar arteries

Innovation of psoas major

Ventral rami of L1-L3

FYI of psoas minor

- Absent in 40% of individuals

- DOES NOT exit abdominal cavity like major

Attachments of psoas minor

T12 and L1/discs & pectinial line

Function of psoas minor

Weak flexion of lumbar vertebral column

Blood supply of psoas minor

Lumbar arteries

Innervation of psoas minor

Anterior rami of L1

Attachments of iliacus

Iliac fossa & lesser trochanter of femur

Function of iliacus

Flexes thigh at high

Blood supply of iliacus

Lumbar and iliolumbar arteries

Innervation of iliacus

Femoral nerve (L2-L4)

Which muscles are responsible for flexing the thigh at the hip?

Psoas major and iliacus (iliopsoas)

Which muscles work together to flex the vertebral column against resistance?

Psoas major and iliacus (iliopsoas)

Nerve of T12

Subcostal

Nerve of T12-L1

Iliohypogastric

Nerve of L1

Ilioinguinal

Nerve of L2-L3

Lateral femoral cutaneous

Nerve of L2-L4

Femoral & obturator

Nerve of L1-L2

Genital femoral

Subcostal nerve

Sensory: T12 dermatome

Motor: Lateral and anterior abdominal wall muscles

Iliohypogastric nerve

Sensory: Above pubis and laterally along QL to abdominal wall

Motor: Abdominal wall

Ilioinguinal nerve

Sensory: Inguinal region, labia majora, uppermedial thigh (across inguinal canal to genital)

Motor: Abdominal wall

Location/passage of genitofemoral nerve

Through psoas

Genitofemoral nerve branches

Genital branch/motor: Deep inguinal ring to cremasteric muscle (male), terminates at labia majora (female)

Femoral branch/sensory: Upper anterior thigh

Lateral femoral cutaneous

Sensory: Lateral thigh (through psoas, posterior to inguinal ligament)

Femoral nerve

Sensory and motor: Anterior thigh

Location/passage of femoral nerve

Lateral to psoas major, exits abdominal with femoral artery

Obturator nerve

Sensory and motor: Medial thigh

Location/passage of obturator nerve

Posterioromedially to psoas, exits obturator canal