BIO 313 Lab - Urinary System

Adrenal gland (suprarenal gland)

Hormone-producing glands located superior to the kidneys.

Pyramid shaped.

Afferent arteriole

The small artery that carries blood toward the capillaries of the glomerulus.

Ascending limb

The limb of the loop of Henle that carries fluid from the medulla towards the cortex of the kidney (distal convoluted tubule).

Impermeable to water.

Capsule

Outer membrane covering kidney.

Collecting duct

Collects urine from multiple distal convoluted tubules, passes through renal pyramid and empties through renal papilla into minor calyx.

Cortex

Outer, light colored region extending from capsule to base of pyramids and into spaces between pyramids as renal columns.

Descending limb

The limb of the loop of Henle that carries fluid from the cortex towards the medulla of the kidney.

Permeable to water.

Distal convoluted tubule

Short, twisted segment connecting nephron loop with collecting duct.

Efferent arteriole

Carries blood away from glomerulus into peritubular capillary bed.

Letter A in picture.

External urethral orifice

Opening of the urethra to the outside.

Letter P in picture.

Glomerular capsule (Bowman's capsule)

Double walled tubular component.

Glomerular filtration

The first step in urine formation in which substances in blood pass through the filtration membrane and the filtrate enters the proximal convoluted tubule of the nephron.

Glomerulus

Capillary bed located within glomerular capsule.

Hilum

Notch, or indentation, in center of medial surface of kidney.

Location of entrance/exit of renal vessels, nerves (consist of sympathetic fibers that regulate vascular smooth muscle of kidneys and renin secretion), and ureter.

Kidney

Paired, bean-shaped organs located just above the waist between the parietal peritoneum and the posterior wall of the abdomen.

Retroperitoneal.

Right kidney is slightly lower than the left kidney (due to liver).

Average adult kidney: 1 - 1 1/2" thick, 2 1/2" wide, 5 1/2" long.

Major calyx

Minor calices combine to form major calices.

Minor calyx

Cup-like structure attached to apex of each pyramid; collects urine from collecting ducts of attached pyramid.

Medulla

Inner, darker region of kidney.

Consists of renal pyramids and renal papillae.

Nephron

The functional unit of the kidney that produces urine.

Each is composed of a tubular and a vascular component.

First part: in cortex; renal corpuscle.

Nephron loop

Loop of Henle

Consists of:

-descending limb

-nephron loop (bend in tubule)

-ascending limb

Penile urethra

Portion of male urethra that passes through the penis to the external urethral orifice.

Prostatic urethra

Portion of the male urethra that passes through the prostate gland.

Proximal convoluted tubule

Short, twisted segment connecting the glomerular capsule with the nephron loop.

Renal artery

Delivers blood to kidney (nearly 25% of resting cardiac output cycles through the kidney with each heartbeat).

Branches into progressively smaller and smaller vessels inside the kidney.

Posterior to renal vein at hilum of kidney.

Renal column

Area of cortical tissue running between the medullary pyramids.

Renal corpuscle

First part of the nephron.

Responsible for the initial step in urine formation (glomerular filtration).

Consists of:

-glomerular capsule

-glomerulus

Renal papilla

Apex of renal pyramid.

Directed toward center of kidney.

Drains urine into minor calices.

Renal pelvis

Major calices drain into expanded region at origin of ureter.

Renal pyramid

Dense network of nephrons.

Triangular shaped subdivisions of medulla of kidney.

Renal vein

Carries blood exiting kidneys to inferior vena cava.

Anterior to renal artery.

Letter D in picture.

Retroperitoneal

Located behind the peritoneum.

Ureter

Slender tube that is a continuation of the renal pelvis that courses to the urinary bladder.

Located retroperitoneal.

Peristaltic waves of smooth muscle contraction in the wall of the ureters propels urine into the bladder.

Urethra

The duct that conducts urine from the neck of the bladder to the outside of the body via the external urethral orifice.

Urinary bladder

A hollow, muscular, and collapsible organ located in the pelvic region posterior to the pubic symphysis.

Has two separate openings for each of the two ureters and an opening for the urethra.

Urine

Fluid wastes removed from the body by the kidneys.

Components:

-Urea

-Na+

-K+

-PO4^3-

-SO4^2-

-Creatinine

-Uric acid

-Smaller amounts: Ca^2+, Mg^2+, HCO3^-

Flow of blood through kidney

renal artery-->interlobar artery-->arcuate artery-->cortical radiate artery-->afferent arteriole-->glomerular capillaries-->efferent arteriole-->peritubular capillaries-->vasa recta-->cortical radiate vein-->arcuate vein-->interlobar vein-->renal vein

Flow of filtrate and urine through urinary system

1. glomerulus

2.capsular space

3.PCT

4. loop of hence

5.DCT

6. collecting Duct

7. Papillary duct

8. minor calyx

9. major calyx

10. renal pelvis

11. ureter

12. urinary bladder

13. urethra

14. external urethral orifice

Urethra comparison

Female:

-length: 1.5"

-embedded in the anterior wall of the vagina

-external urethral orifice lies in vestibule between vaginal opening and clitoris

-UTIs are not uncommon due to shortness of urethra and proximity of external urethral orifice to anus

Male:

-length: 8"

-prostatic urethra

penile urethra

-2 functions: passageway for semen (reproductive) and urine (urinary)

Urinalysis

Gross inspection:

-color

-turbidity

Dipstick

-specific gravity

-pH

-glucose

-heme

-protein

-leukocyte esterase

-nitrites

-ketones

-bilirubin/urobilinogen

Microscopy:

-WBCs

-RBCs

-bacteria

-crystals

-casts

Glucosuria

The presence of detectable amounts of glucose in the urine.

Proteinuria

Urinary protein concentration is greater than normal.

Bilirubinuria

The presence of bilirubin in the urine.

Ketonuria

The presence of ketone bodies (acetoacetic acid, beta-hydroxybutyric acid, acetone) n the urine.

Hematuria

The presence of an abnormally high number of red blood cells in the urine.

Hemoglobinuria

The presence of hemoglobin in the urine.

Bacteriuria

The presence of bacteria in the urine.

Pyuria

The presence of significant number of white blood cells in the urine.

Cortex histology

Medulla histology

Medulla vs cortex