generate all key high yield info for Respiration and Integration R&I block for 1st year students M1 for batterjee medical college examinations jeddah for lectures “Glomerular filtration” physiology “Histology of Kidney”, “Tubular processing of Glomerular filtrate” , “Anatomy of kidney and suprarenal gland”, Make sure all info is relevant for batterjee medical college examinations and then at end of each topic generate all high yield mcqs that appear frequently in past year BMC exams and put pictures

Reading File

Finding Sources

Reading File

Finding Sources

Reading File

Finding Sources

Reading File

Searching Images

kidney anatomy cortex medulla nephron cross section diagram

Searching Images

glomerular filtration barrier Bowman capsule podocyte diagram

Reading File

Searching Images

kidney histology proximal tubule distal tubule collecting duct light microscopy

Searching Images

suprarenal adrenal gland anatomy zones cortex medulla

Reading File

Searching Images

tubular reabsorption proximal tubule sodium glucose cotransport diagram physiology

Searching Images

renal clearance GFR starling forces filtration fraction diagram

🏥 BMC M1 — R&I Block High-Yield Study Guide

Batterjee Medical College, Jeddah | First Year | Examinations Preparation

TOPIC 1: GLOMERULAR FILTRATION — Physiology

📌 Overview of Renal Processes

Urine formation results from three sequential processes:

Urinary Excretion = Filtration − Reabsorption + Secretion

Process	Location	Key Feature
Glomerular filtration	Glomerulus → Bowman's capsule	Bulk, non-selective (except proteins)
Tubular reabsorption	All tubule segments	Selective, high-volume
Tubular secretion	Tubules → lumen	Organic acids/bases, K⁺, H⁺

Figure: Four patterns of renal handling — filtration only (A), partial reabsorption (B), complete reabsorption (C), filtration + secretion (D)

📌 Glomerular Filtration Rate (GFR)

Parameter	Normal Value
GFR (both kidneys)	125 mL/min = 180 L/day
Renal blood flow	~20–25% of cardiac output
Filtration fraction	~20% (GFR/RPF)
Plasma protein concentration in filtrate	~0 (proteins NOT filtered)

Why is a high GFR critical?

Exposes the entire ECF to tubular scrutiny >10 times/day
Allows rapid elimination of toxins
In ESRD (GFR reduced to 10% of normal), BUN rises ~10× to maintain excretion balance

📌 Glomerular Filtration Barrier (3 Layers)

Layer	Feature	Function
Fenestrated endothelium	70–100 nm pores	Blocks blood cells, allows water + solutes
Glomerular basement membrane (GBM)	Negatively charged collagen IV	Charge barrier (repels albumin)
Podocytes (visceral epithelium)	Foot processes + filtration slits	Size + charge selectivity

Figure: Scanning EM of glomerulus showing capillary loops, podocytes, foot processes, Bowman's capsule, and filtration slits

📌 Starling Forces Governing Filtration

Net Filtration Pressure = (P_GC − P_BS) − (π_GC − π_BS)

Force	Direction	Approx. Value
Glomerular capillary hydrostatic pressure (P_GC)	↑ Filtration	~60 mmHg
Bowman's space hydrostatic pressure (P_BS)	↓ Filtration	~18 mmHg
Glomerular oncotic pressure (π_GC)	↓ Filtration	~32 mmHg
Bowman's space oncotic pressure (π_BS)	↑ Filtration	~0 mmHg
Net filtration pressure		~10 mmHg

📌 Factors That Change GFR

Factor	Effect on GFR	Mechanism
↑ Afferent arteriole constriction	↓ GFR	↓ P_GC
↑ Efferent arteriole constriction	↑ then ↓ GFR	↑ P_GC initially, then ↑ oncotic pressure
Angiotensin II	↑ Efferent tone → maintains GFR in low flow	Efferent constriction
NSAIDs	↓ GFR	Block prostaglandins → afferent constriction
↑ Plasma protein	↓ GFR	↑ oncotic pressure
Urinary obstruction	↓ GFR	↑ P_BS

📌 GFR Measurement — Renal Clearance

Clearance = (U_x × V̇) / P_x

Gold standard marker = INULIN (exogenous)

Freely filtered, NOT reabsorbed, NOT secreted, NOT synthesized or broken down
Inulin clearance = GFR exactly

Clinical estimate = Creatinine clearance

Creatinine is freely filtered + small amount secreted → slightly overestimates GFR (~140 mL/min vs 125 mL/min)

Substance	Clearance (mL/min)	Interpretation
Glucose	0	Completely reabsorbed
Sodium	0.9	Mostly reabsorbed
Inulin	125	GFR marker
Creatinine	~140	Filtered + secreted
PAH	~625	Filtered + secreted → measures RPF

Key rule:

Clearance < inulin → net reabsorption
Clearance > inulin → net secretion
Clearance = inulin → only filtered

📌 Autoregulation of GFR

GFR is maintained constant over MAP 80–180 mmHg via:

Myogenic mechanism — afferent arteriole constricts when stretched
Tubuloglomerular feedback (TGF) — macula densa senses ↑ NaCl → releases adenosine → afferent constriction

🧠 High-Yield MCQs — Glomerular Filtration

Q1. Normal GFR in an adult is:

A) 60 mL/min
B) 100 mL/min
C) 125 mL/min ✓
D) 180 mL/min

GFR = 125 mL/min (180 L/day). This is a consistently tested value at BMC.

Q2. Which substance is used as the gold standard to measure GFR?

A) Creatinine
B) PAH
C) Inulin ✓
D) Urea

Inulin is freely filtered, neither reabsorbed nor secreted, not metabolized, physiologically inert.

Q3. A substance has a clearance of 70 mL/min. Inulin clearance is 125 mL/min. This substance is:

A) Only filtered
B) Filtered and partially reabsorbed ✓
C) Filtered and secreted
D) Not filtered at all

Clearance < inulin → net reabsorption occurs.

Q4. Which of the following DECREASES GFR?

A) Dilation of afferent arteriole
B) ↑ Glomerular capillary pressure
C) NSAIDs ✓
D) ↑ Renal blood flow

NSAIDs block prostaglandins → afferent arteriole constricts → ↓ P_GC → ↓ GFR. Critical for pharmacology integration.

Q5. The filtration barrier between glomerular blood and Bowman's space includes all EXCEPT:

A) Fenestrated endothelium
B) Glomerular basement membrane
C) Podocyte filtration slits
D) Macula densa cells ✓

Macula densa is part of tubuloglomerular feedback, not the filtration barrier.

Q6. Oncotic pressure in Bowman's capsule is normally:

A) 32 mmHg
B) 18 mmHg
C) 0 mmHg ✓
D) 10 mmHg

Virtually no protein enters the filtrate, so oncotic pressure in Bowman's space ≈ 0.

Q7. Creatinine clearance slightly overestimates GFR because creatinine is:

A) Reabsorbed by tubules
B) Secreted by tubules ✓
C) Synthesized in tubules
D) Bound to plasma proteins

Q8. What is the filtration fraction?

A) GFR/Renal Blood Flow
B) GFR/Renal Plasma Flow ✓
C) Urine output/Plasma volume
D) Filtered load/Excreted amount

FF = GFR/RPF = 125/625 ≈ 20%

TOPIC 2: HISTOLOGY OF THE KIDNEY

📌 Overview of Renal Histology

The kidney is composed of cortex and medulla. The functional unit is the nephron (~1 million per kidney).

Figure: Labeled nephron showing Bowman's capsule, glomerulus, proximal tubule, Loop of Henle, distal tubule, collecting duct in cortex and medulla (Harrison's)

📌 Nephron Components — Histological Features

1. Renal Corpuscle (Glomerulus + Bowman's Capsule)

Component	Histology	Notes
Glomerulus	Tuft of fenestrated capillaries	Supported by mesangial cells
Parietal layer of Bowman's capsule	Simple squamous epithelium	Lines outer capsule
Visceral layer	Podocytes (modified epithelium)	Foot processes wrap capillaries
Mesangial cells	Between capillary loops	Phagocytic, contractile, matrix production
Juxtaglomerular (JG) cells	Modified smooth muscle of afferent arteriole	Secrete renin
Macula densa	Columnar cells of distal tubule	Senses NaCl; controls renin release

2. Proximal Convoluted Tubule (PCT)

Feature	Detail
Epithelium	Simple cuboidal with prominent brush border (microvilli)
Cytoplasm	Highly eosinophilic (acidophilic) — many mitochondria
Lumen	Relatively narrow, indistinct (due to brush border)
Location	Cortex
Function	Reabsorbs ~65–70% of filtered Na, water, glucose, amino acids, HCO₃⁻

BMC HY: PCT is distinguished from DCT by: larger cells, more eosinophilic cytoplasm, brush border, narrower lumen.

3. Loop of Henle

Segment	Epithelium	Permeability
Descending thin limb	Simple squamous	Permeable to water; impermeable to solutes
Ascending thin limb	Simple squamous	Impermeable to water
Thick ascending limb	Simple cuboidal/columnar; NO brush border	Actively transports Na, K, Cl (NKCC2)

4. Distal Convoluted Tubule (DCT)

Feature	Detail
Epithelium	Simple cuboidal, NO brush border
Cytoplasm	Less eosinophilic than PCT
Lumen	Relatively wider, more distinct than PCT
Location	Cortex — returns near glomerulus of origin
Function	Reabsorbs Na (aldosterone-sensitive); Ca²⁺ reabsorption (PTH)

5. Collecting Duct

Feature	Detail
Principal cells	Pale cytoplasm, respond to ADH (AQP2 insertion) and aldosterone
Intercalated cells (Type A)	Dark cytoplasm, secrete H⁺; reabsorb K⁺
Intercalated cells (Type B)	Secrete HCO₃⁻
Epithelium	Simple cuboidal → columnar in papillary duct

📌 PCT vs DCT Comparison Table (High-Yield)

Feature	PCT	DCT
Brush border	Yes (prominent)	No
Cell size	Larger	Smaller
Cytoplasm	Strongly eosinophilic	Pale/less eosinophilic
Lumen	Narrow, irregular	Wider, distinct
Mitochondria	Abundant (basal striations)	Moderate
% of cortex area	More numerous	Fewer

📌 Juxtaglomerular Apparatus (JGA)

Components:

JG cells — modified smooth muscle of afferent arteriole → secrete renin
Macula densa — modified DCT cells sensing NaCl delivery
Extraglomerular mesangial cells (lacis cells) — between JG cells and macula densa

Function: Regulates GFR (tubuloglomerular feedback) and systemic blood pressure (RAAS).

📌 Renal Interstitium

Cortical interstitium: sparse, few fibroblasts
Medullary interstitium: prominent fibroblasts that synthesize prostaglandins and erythropoietin

🧠 High-Yield MCQs — Histology of Kidney

Q1. The proximal convoluted tubule is distinguished histologically by:

A) Wide clear lumen and pale cells
B) Brush border and eosinophilic cytoplasm ✓
C) Simple squamous epithelium
D) Absence of mitochondria

Q2. Which cells of the kidney produce renin?

A) Podocytes
B) Juxtaglomerular (JG) cells ✓
C) Macula densa cells
D) Principal cells of collecting duct

JG cells are modified smooth muscle cells of the afferent arteriole.

Q3. The macula densa is located in which part of the nephron?

A) Proximal convoluted tubule
B) Ascending thick limb of Henle
C) Distal convoluted tubule ✓
D) Collecting duct

Q4. In a kidney cross section, tubules with NO brush border, pale cytoplasm, and wider lumens are most likely:

A) Proximal convoluted tubules
B) Distal convoluted tubules ✓
C) Thick ascending loop of Henle
D) Collecting ducts

Q5. Which cells in the collecting duct are responsible for water reabsorption in response to ADH?

A) Principal cells ✓
B) Type A intercalated cells
C) Type B intercalated cells
D) JG cells

Q6. The visceral layer of Bowman's capsule is composed of:

A) Simple squamous epithelium
B) Podocytes ✓
C) Columnar epithelium
D) Transitional epithelium

Q7. Which segment of the nephron is impermeable to water but actively transports NaCl?

A) Descending thin limb of Henle
B) Thick ascending limb of Henle ✓
C) Collecting duct (without ADH)
D) Proximal tubule

This is the "diluting segment" — impermeable to water, active NKCC2 transport builds medullary gradient.

Q8. Mesangial cells in the glomerulus are important because they:

A) Filter blood
B) Produce renin
C) Are phagocytic and provide structural support ✓
D) Reabsorb glucose

TOPIC 3: TUBULAR PROCESSING OF GLOMERULAR FILTRATE

📌 Key Concept

The kidney filters 180 L/day but excretes only ~1.5 L — reabsorbs 99% of the filtrate.

Tubular reabsorption is quantitatively large and highly selective — glucose and amino acids are 100% reabsorbed; waste products (urea, creatinine) are poorly reabsorbed.

📌 Proximal Tubule — Bulk Reabsorption (~65–70%)

Substance	% Reabsorbed	Mechanism
Na⁺	~65%	Na⁺/K⁺-ATPase (basolateral); passive via tight junctions
Water	~65% (iso-osmotic)	Osmosis through AQP1
Glucose	100% (at normal plasma levels)	SGLT2 (apical), GLUT2 (basolateral)
Amino acids	~100%	Na⁺-coupled cotransporters
HCO₃⁻	~80%	Na⁺/H⁺ exchange + carbonic anhydrase
Phosphate	~80%	Na⁺-phosphate cotransporter (inhibited by PTH)
Urea	~50% passive	Passive (follows water)
K⁺	~65%	Passive, paracellular

Glucose Transport Maximum (Tm):

Transport maximum for glucose = 375 mg/min
Threshold plasma glucose = ~180 mg/dL → above this, glucose spills into urine (glucosuria)

📌 Loop of Henle — Countercurrent Mechanism

Limb	Water	Solute
Descending thin	Permeable	Impermeable → fluid becomes concentrated
Ascending thin	Impermeable	Some passive NaCl diffusion
Thick ascending	Impermeable	Active NKCC2 transport (blocked by furosemide)

→ Creates hypertonic medullary interstitium → essential for urine concentration

📌 Distal Tubule & Collecting Duct — Fine-Tuning

Segment	Key Transporters	Regulated By
DCT	Na⁺-Cl⁻ cotransporter (NCC)	Aldosterone
DCT	Ca²⁺ reabsorption (TRPV5)	PTH, Vitamin D
Collecting duct principal cells	ENaC (Na), ROMK (K secretion)	Aldosterone
Collecting duct principal cells	AQP2 insertion	ADH (vasopressin)
Type A intercalated cells	H⁺-ATPase	Acid-base balance

📌 Hormonal Control of Tubular Processing

Hormone	Site of Action	Effect
Aldosterone	DCT + collecting duct	↑ Na⁺ reabsorption, ↑ K⁺ secretion, ↑ H⁺ secretion
ADH (vasopressin)	Collecting duct	↑ Water reabsorption via AQP2
PTH	PCT + DCT	↓ Phosphate reabsorption, ↑ Ca²⁺ reabsorption
Angiotensin II	PCT	↑ Na⁺/H⁺ exchange → ↑ Na⁺ reabsorption
ANP/BNP	Collecting duct	↓ Na⁺ reabsorption

📌 Potassium Handling

PCT: 65% reabsorbed passively
Thick ascending: 25–30% reabsorbed via NKCC2
Collecting duct: K⁺ secretion regulated by aldosterone
Hypokalemia → ↓ K⁺ secretion; Hyperkalemia → ↑ K⁺ secretion via ROMK

📌 Urea Recycling

~50% reabsorbed in PCT passively
Secreted in thin limbs of Henle
Reabsorbed in collecting duct (facilitated by UT-A1 transporters, stimulated by ADH)
Urea recycling contributes to medullary hypertonicity

📌 Acidification of Urine (H⁺ Secretion)

Location	Mechanism	% of H⁺
PCT	Na⁺/H⁺ exchanger (NHE3)	~80%
Thick ascending	NHE3	Small
Collecting duct Type A	H⁺-ATPase & H⁺/K⁺-ATPase	~20%

Buffers in urine: phosphate (titratable acid) and ammonia (NH₃ → NH₄⁺)

Figure: Proximal tubule apical and basolateral transporters — SGLT2, NHE3, Na-phosphate, Na-amino acid cotransporters (Harrison's)

🧠 High-Yield MCQs — Tubular Processing

Q1. At normal plasma glucose levels, glucose is:

A) Filtered and 50% reabsorbed
B) Completely reabsorbed in the proximal tubule ✓
C) Secreted by the distal tubule
D) Excreted in small amounts

SGLT2 in PCT reabsorbs all filtered glucose at plasma levels <180 mg/dL.

Q2. Furosemide (a loop diuretic) works by blocking:

A) Na⁺/K⁺-ATPase
B) NKCC2 in the thick ascending limb ✓
C) ENaC in the collecting duct
D) SGLT2 in the proximal tubule

Q3. Aldosterone primarily acts on which cells?

A) JG cells
B) Proximal tubule cells
C) Principal cells of the collecting duct ✓
D) Podocytes

Aldosterone → ↑ ENaC expression → ↑ Na⁺ reabsorption, ↑ K⁺ secretion.

Q4. ADH (vasopressin) increases water reabsorption by inserting which channel?

A) AQP1
B) AQP3
C) AQP2 ✓
D) ROMK

ADH → V2 receptor → cAMP → AQP2 insertion into apical membrane of principal cells.

Q5. A patient with plasma glucose of 250 mg/dL will have glucosuria because:

A) Glucose is poorly filtered
B) GLUT2 is saturated in the DCT
C) The transport maximum (Tm) for glucose is exceeded ✓
D) ADH inhibits glucose reabsorption

Q6. PTH acts on the kidney to:

A) ↑ Phosphate reabsorption
B) ↓ Phosphate reabsorption + ↑ Ca²⁺ reabsorption ✓
C) ↑ Na⁺ reabsorption
D) ↓ Water reabsorption

Q7. The descending thin limb of Henle is:

A) Impermeable to water, permeable to NaCl
B) Permeable to water, impermeable to NaCl ✓
C) Permeable to both water and NaCl
D) Active transporter of NKCC2

Descending limb: water leaves → fluid becomes concentrated. Ascending limb: NaCl leaves (active) → fluid becomes diluted.

Q8. Which formula is used to determine if net reabsorption or secretion occurred?

A) GFR = (U_x × V̇)/P_x
B) Filtered load = GFR × P_x; compare to excreted amount ✓
C) Osmolality = 2 × [Na] + glucose/18 + BUN/2.8
D) Clearance = U_x/P_x

If excreted < filtered → reabsorption; if excreted > filtered → secretion.

TOPIC 4: ANATOMY OF THE KIDNEY AND SUPRARENAL GLAND

📌 Position & Relations of the Kidney

Feature	Right Kidney	Left Kidney
Vertebral level	T12–L3	T12–L3 (slightly higher)
Peritoneal relation	Retroperitoneal	Retroperitoneal
Anterior relations	Liver, right flexure of colon, 2nd part of duodenum (no peritoneum)	Stomach, spleen, pancreas, left flexure of colon
Superior relation	Right suprarenal gland	Left suprarenal gland

Key point: Right kidney is lower than the left (liver pushes it down). The right kidney is directly related to the 2nd part of duodenum (retroperitoneal, no peritoneum between them).

📌 External Anatomy

Shape: Bean-shaped, ~11 cm × 6 cm × 3 cm
Weight: 125–170 g (men); 115–155 g (women)
Hilus: Medial concave border — entry of renal artery + nerves; exit of renal vein, lymphatics, ureter
Renal sinus: Space inside hilus containing renal pelvis, calyces, vessels, fat
Renal capsule: Fibrous, non-distensible

Figure: Coronal cross-section of kidney showing cortex, medulla (pyramids), calyces, renal pelvis, and ureter

📌 Internal Structure

Layer	Contents
Cortex (outer, granular)	Glomeruli, PCT, DCT, cortical collecting ducts
Medulla (inner, striated)	Loops of Henle, collecting ducts, vasa recta
Renal pyramids (8–18)	Medullary cones, base at corticomedullary junction, apex = renal papilla
Renal columns (of Bertin)	Cortical tissue between pyramids
Minor calyx → Major calyx → Renal pelvis → Ureter	Urine drainage

📌 Renal Blood Supply

Pathway:

Aorta → Renal artery → Segmental arteries → Interlobar arteries → Arcuate arteries (at corticomedullary junction) → Interlobular arteries → Afferent arterioles → Glomerular capillaries → Efferent arterioles → Peritubular capillaries / Vasa recta → venous drainage

Feature	Note
Renal artery origin	Lateral aorta at L1–L2
Right renal artery	Longer; passes posterior to IVC
Segmental arteries	End arteries — no anastomoses → infarcts are wedge-shaped
Vasa recta	Supply medulla; form countercurrent exchange system

📌 Two Types of Nephrons

Type	Location	Loop of Henle	Function
Cortical nephrons (85%)	Outer cortex	Short loop	General filtration
Juxtamedullary nephrons (15%)	Inner cortex	Long loop into deep medulla	Urine concentration via countercurrent

📌 Renal Lymphatics & Nerves

Lymph: follows renal vessels → paraaortic lymph nodes
Nerves: Renal plexus (T10–L1) sympathetic fibers; renal pain referred to loin/groin (T10–L1 dermatomes)

📌 Suprarenal (Adrenal) Glands

Feature	Right	Left
Shape	Pyramidal	Semilunar (crescent)
Position	Anteromedial to upper right kidney	Anteromedial to upper left kidney
Relation	IVC anteromedially; liver anteriorly	Aorta; left renal vein; splenic vessels
Weight	~4 g	~4 g

Blood supply:

Superior suprarenal artery → inferior phrenic artery
Middle suprarenal artery → aorta
Inferior suprarenal artery → renal artery
Single suprarenal vein: Right → IVC; Left → left renal vein

📌 Histology of the Suprarenal Gland

Figure: Adrenal gland zones — glomerulosa (mineralocorticoids), fasciculata (glucocorticoids), reticularis (androgens), medulla (catecholamines)

Mnemonic: GFR + M → "Go Find Receptor Medulla"

Zone	Cells Arrangement	Hormone
Zona glomerulosa (outer)	Rounded clusters	Aldosterone (mineralocorticoid)
Zona fasciculata (middle, thickest)	Parallel cords; lipid-laden "spongiocytes"	Cortisol (glucocorticoid)
Zona reticularis (inner)	Anastomosing cords	Androgens (DHEA)
Medulla (innermost)	Chromaffin cells	Epinephrine (80%), Norepinephrine (20%)

BMC HY: Zona fasciculata is the thickest zone. Chromaffin cells of the medulla are modified postganglionic sympathetic neurons. The right suprarenal vein drains directly into the IVC (clinically important in laparoscopic surgery).

🧠 High-Yield MCQs — Anatomy of Kidney and Suprarenal Gland

Q1. The kidneys lie at which vertebral level?

A) L1–L4
B) T12–L3 ✓
C) T10–L1
D) L2–L5

Q2. The right kidney is lower than the left because:

A) The liver occupies the right upper quadrant ✓
B) The right renal artery is longer
C) The right suprarenal gland is larger
D) The right ureter is shorter

Q3. The renal artery originates from the aorta at which level?

A) T12
B) L1–L2 ✓
C) L3
D) T10

Q4. Segmental arteries of the kidney are:

A) Freely anastomosing
B) End arteries ✓
C) Branches of the renal vein
D) Located in the renal pelvis

End arteries = no anastomoses → occlusion causes wedge-shaped infarction.

Q5. Cortical tissue extending between medullary pyramids is called:

A) Minor calyx
B) Renal sinus
C) Columns of Bertin (renal columns) ✓
D) Vasa recta

Q6. Juxtamedullary nephrons differ from cortical nephrons in that they:

A) Lack a glomerulus
B) Are more numerous (85%)
C) Have longer loops of Henle extending into deep medulla ✓
D) Do not have efferent arterioles

Q7. The left suprarenal vein drains into:

A) Inferior vena cava
B) Left renal vein ✓
C) Aorta
D) Left gonadal vein

Right suprarenal vein → IVC directly; Left suprarenal vein → left renal vein.

Q8. Which zone of the adrenal cortex is responsible for cortisol production?

A) Zona glomerulosa
B) Zona fasciculata ✓
C) Zona reticularis
D) Adrenal medulla

Q9. Which structure passes through the renal hilus?

A) Renal artery, renal vein, ureter
B) Renal artery and ureter only
C) Renal artery, renal vein, ureter, lymphatics, and nerves ✓
D) Ureter and renal vein only

Q10. The arcuate arteries of the kidney are located at:

A) Cortical surface
B) Corticomedullary junction ✓
C) Renal sinus
D) Deep medulla

Q11. Chromaffin cells of the adrenal medulla are embryologically derived from:

A) Mesoderm (same as adrenal cortex)
B) Neural crest cells ✓
C) Endoderm
D) Lateral plate mesoderm

Adrenal cortex → mesoderm; Adrenal medulla → neural crest (modified sympathetic neurons).

Q12. Which anterior relation of the right kidney has NO peritoneum between them?

A) Liver
B) 2nd part of duodenum ✓
C) Right colic flexure
D) Small intestine

The duodenum is also retroperitoneal, so it lies directly against the right kidney without a peritoneal layer.

📋 Quick Summary Table — All 4 Topics

Topic	Most Tested Values/Facts
Glomerular Filtration	GFR = 125 mL/min; Inulin = gold standard; FF = 20%; Net filtration pressure ~10 mmHg
Kidney Histology	PCT = brush border + eosinophilic; DCT = no brush border, wide lumen; JG cells → renin; Macula densa = DCT
Tubular Processing	Glucose 100% reabsorbed (PCT, SGLT2); Tm glucose ~375 mg/min; threshold ~180 mg/dL; Aldosterone → Na reabsorption; ADH → AQP2
Kidney & Suprarenal Anatomy	Kidneys T12–L3 retroperitoneal; Right kidney lower; Renal artery at L1–L2; End arteries; Right adrenal vein → IVC; Left → renal vein; Zona fasciculata = cortisol

Sources: Guyton & Hall Textbook of Medical Physiology (9780443111013); Medical Physiology — Boron & Boulpaep (9780323319737); Harrison's Principles of Internal Medicine, 21st Ed.; Ganong's Review of Medical Physiology, 26th Ed.

This is a shared conversation. Sign in to Orris to start your own chat.