Anatomy of the Kidney

Comprehensive vocabulary flashcards detailing the anatomical features, dimensions, relations, blood supply, coverings, and microscopic layout of the human kidneys based on lecture notes.

Excretory Systems

The four main waste elimination systems in the human body, consisting of the urinary system, bowel, lungs, and skin.

Components of Urinary System

The anatomical structures that make up the urinary system: $2$ kidneys, $2$ ureters, $1$ urinary bladder, and $1$ urethra.

Functions of the Kidneys

Kidneys remove waste products of metabolism, excess water, and salts from blood, and maintain systemic pH.

Retroperitoneal Location

The position of the kidneys situated on the posterior abdominal wall, one on each side of the vertebral column, located behind the peritoneum.

Vertebral Extent of the Kidneys

The vertical span of the kidneys occupying the lumbar region, extending from the upper border of T12 to the centre of the body of L3.

Positional Asymmetry of the Kidneys

The right kidney is slightly lower than the left by $1\,\text{cm}$, while the left kidney is located a little nearer to the median plane than the right.

Kidney Dimensions

The external measurements of a kidney, being about $11\,\text{cm}$ long, $5\,\text{cm}$ broad, and $3\,\text{cm}$ thick, with the left kidney being slightly longer and narrower than the right.

Kidney Weight

The average weight of a kidney in adults, which is $150\,\text{g}$ in males and $135\,\text{g}$ in females.

Fetal Kidney Structure

The lobulated form of the kidney during fetal development, made up of about $12$ lobules that fuse after birth to become uniformly smooth in adults.

Renal Hilum

The depressed middle part of the concave medial border of the kidney through which structures enter and exit.

Anterior Relations of the Right Kidney

The anatomical structures located anteriorly to the right kidney: suprarenal gland, liver, second part of the duodenum, and right colic flexure.

Anterior Relations of the Left Kidney

The anatomical structures located anteriorly to the left kidney: suprarenal gland, spleen, stomach, pancreas, left colic flexure, and coils of jejunum.

Posterior Relations of the Kidneys

Structures located posterior to the kidneys including the diaphragm, costodiaphragmatic recess of the pleura, ribs (11th and 12th for left; 12th for right), psoas, quadratus lumborum, and transversus abdominis muscles, along with subcostal (T12), iliohypogastric (L1), and ilioinguinal (L1) nerves.

Renal Arteries

Large arterial vessels that supply the kidneys, arising as direct branches from the abdominal aorta.

Renal Veins

Venous structures draining blood from the kidneys into the inferior vena cava, with the left renal vein being longer than the right.

Nerve Supply of the Kidney

Innervation consisting of sympathetic fibers derived from T12–L1 segments and parasympathetic fibers derived from the vagus nerve.

Renal Pelvis

A dilated sac occupying the renal sinus that divides inside the sinus into two or three major calices.

Minor Calyx

A cup-shaped structure ( numbering $10$ to $12$ per kidney) that surrounds one or more renal papillae to collect urine from the papilla.

Fibrous Capsule

The innermost layer or true capsule directly surrounding and covering the kidney.

Perinephric Fat

The middle fatty capsule consisting of a collection of fatty tissue that acts as a shock absorber and helps maintain the kidney in its anatomical position.

Renal Fascia

The outermost false capsule composed of anterior and posterior layers that enclose the kidney and suprarenal gland, merging superiorly with diaphragmatic fascia to move with respiration.

Uriniferous Tubule

The microscopic structural component of the kidney, consisting of an excretory part called a nephron and a collecting tubule.

Nephron

The basic functional excretory subunit of the uriniferous tubule, occurring in numbers of over one million per kidney.

Morris Parallelogram

A surface marking diagram on the back defined by horizontal lines at T11 and L3 spine levels and vertical distance lines at $2.5\,\text{cm}$ and $9\,\text{cm}$ from the midline, used to outline the position of the kidneys.

Renal Angle

The angle formed between the last rib and the lateral border of the erector spinae muscle, occupied by the kidney.

Vertebrocostal Angle

The angle formed between the last rib and the lateral border of the vertebral column, occupied by the lower part of the pleural sac.