By :Sweet Yvonne Regalado

Human Urinary System

kidney

Urinary system

ureter

uretra

Gallbladder

URINARY SYSTEM

also called the EXCRETORY SYSTEM is the organ system that

produces, stores, and eliminates urine. In humans it includes two kidneys, two

ureters, the bladder and the urethra.

Kidney

Kidney bean shape lie against the dorsal wall in a retroperitoneal position in the superior lumbar region

Remove liquid waste from the blood in the form of urine.

Keep a stable balance of salts and other substances in the blood.

Produce erythropoietin, a hormone that aids the formation of red blood cells.

Renal capsule◦ Surrounds each kidney◦ Gives a fresh kidney a glistening

appearance

Adipose capsule◦ Surrounds the kidney◦ Provides protection to the kidney◦ Helps keep the kidney in its correct

location

Ptosis◦ is a condition when the kidney drop into a

lower position

Hydronephrosis◦ condition when urine can no longer pass

through the ureters back up and exert pressure on the kidneys tissue.

RENAL CORTEX -the outer region, which is light in color

RENAL MEDULLA -deep to the cortex is a darker reddish-brown area.◦ Basically with a triangular regions with a striped

appearance the medullary pyramids.◦ The pyramids are separated by extensions of cortex

like tissue called the renal columns.

RENAL PELVIS – medial to the hilus is a basin like cavity.◦ Extension of the pelvis(calyxes) surround the tips of

medullary pyramid and collect urine draining from them.

Internal anatomy of the kidneyDiagrammatic view of coronally

sectioned kidney, illustrating major blood vessels

Internal anatomy of the kidneyDiagrammatic view of coronally

sectioned kidney, illustrating major blood vessels

The renal artery, which enters the kidney breaks up into segmental, lobar and then interlobar arteries that travel outward through the medulla.

Interlobar arteries split into arcuatearteries which branch to produce interlobular arteries which serve as the cortex.

Structural functional unit of the kidney.

Responsible for forming the urine. Main structures of the nephrons :

◦ Glomerulus◦ Renal tubule (Bowman’s capsule)

A specialized capillary bed Attached to arterioles on both sides

(maintains high pressure)◦ Large afferent

arteriole◦ Narrow efferent

arteriole

Glomerular(Bowman’s) capsule

Proximal convoluted tubule

Loop of Henle

Distal convoluted tubule

CORTICAL NEPHRONS◦ Located entirely

in the cortex◦ Includes most

nephrons

JUXTAMEDULLARY NEPHRONS◦ Found at the boundary

of the cortex and medulla

Arise from efferent arteriole of the glomerulus

Normal, low pressure capillaries Attached to a venule Cling close to the renal tubule Reabsorb (reclaim) some substances

from collecting tubes

Results of three processes FiltrationoGlomerulus act as a filteroNon-selective passive process.

oThe filtrate that is formed is essentially blood plasma without blood protein.

oNonselective passive processoWater and solutes smaller than proteins are

forced through capillary walls

oBlood cells cannot pass out to the capillaries

oFiltrate is collected in the glomerular capsule and leaves via the renal tubule.

ReabsorptionThe filtrate contains many useful substance which must

be reclaimed from the filtrate and returned to the blood.

The peritubular capillaries reabsorb several materials Some water

Glucose

Amino acids

Ions

Some reabsorption is passive, most is active

Most reabsorption occurs in the proximal convoluted tubule.

Nitrogenous waste products◦Urea◦Uric acid◦Creatinine

Excess water

SECRETION - Reabsorption in Reverse

Some materials move from the peritubularcapillaries into the renal tubules Hydrogen and potassium ions

Creatinine

Materials left in the renal tubule move toward the ureter.

Water 99% Sodium 99.5% Glucose 100% Amino acids 100% Phenol 0% Urea 50%

Water 1% Sodium 0.5% Glucose 0% Amino acids 0% Phenol 100% Urea 50

Colored somewhat yellow due to the pigment urochrome (from the destruction of hemoglobin) and solutes.

Sterile Slightly aromatic Normal pH of around 6 Specific gravity of 1.001 to 1.035

Slender tubes attaching the kidney to the bladder◦ Continuous with the renal pelvis◦ Enter the posterior aspect of the bladder

Runs behind the peritoneum Peristalsis aids gravity in urine transport Passageways that carry urine from the kidney

to the bladder.

Smooth, collapsible, muscular sac

Temporarily stores urine

When the bladder is empty it is collapsed,5 to 7.5 cm long at most and its wall are thick and thrown into folds

If the interior of the bladder is scanned three openings are seen-the two ureter openings and the single openings of the urethra which drains the bladder .

The smooth triangular region of the bladder base outlined by these three openings is called trigone.

Trigone is important clinically because infections tend to persist in this region.

Thin-walled tube that carries urine from the bladder to the outside of the body by peristalsis

Release of urine is controlled by two sphincters◦ Internal urethral sphincter (involuntary)◦ External urethral sphincter (voluntary

Both sphincter muscles must open to allow voiding◦ The internal urethral sphincter is relaxed

after stretching of the bladder◦ Activation is from an impulse sent to the

spinal cord and then back via the pelvic splanchnic nerves

◦ The external urethral sphincter must be voluntarily relaxed

Normal amount of water in the human body◦ Young adult females – 50%◦ Young adult males – 60%◦ Babies – 75%◦ Old age – 45%

Water is necessary for many body functions and levels must be maintained

Functional kidneys are developed by the third month

Urinary system of a newborn◦Bladder is small◦Urine cannot be concentrated

There is a progressive decline in urinary function

The bladder shrinks with agingUrinary retention is common in males

Endocrine systems◦ Kidneys dispose of nitrogenous waste; maintain

fluid, electrolyte and acid base balance of blood; produce hormone erythropoitein.

Lymphatic system◦ Immune cell protect urinary organs from

infections, cancer, and other foreign substance.

Digestive system◦ Digestive organs provide nutrients needed for kidney

cell health.

Muscular system◦ Muscles of pelvic diaphragm and external urethral

sphincter function in voluntary control of micturition.

Nervous system◦ Neural controls involved in micturion.

Respiratory system◦ Respiratory system provide oxygen required by kidney

cells.

Cardiovascular system◦ Systemic arterial blood pressure is the driving force

for glomerular filtration.

Reproductive system◦ Kidneys dispose of nitrogenous waste; maintain

fluid, electrolyte and acid base balance of blood.

Integumentary system◦ Skin provides external protective barrier; serves as

site for water loss via perspiration.

Skeletal system◦ Bones of rib cage provide some protection to

kidneys.

Thank you..