Anatomy 2 Urinary System

Proximal Convoluted Tubule Processes

reabsorption

Collecting Duct Processes

reabsorption and secretion

Distal Convoluted Tubule Processes

secretion (RAAS)

Ascending Limb Processes

reabsorption

Renal Corpuscle Processes

filtration

Descending Limb Processes

reabsorption

Proximal Convoluted Tubule Function(s)

water and ions (K+, Cl-, Na+) and organic nutrients (glucose and amino acids) move back to the blood from the filtrate

Ascending Limb Function(s)

ions (Cl- and Na+) leave the tubular fluid and diffuse back into the blood

Renal Corpuscle Function(s)

water and small solutes move (blood to filtrate) blood cells and large solutes stay in the blood

Descending Limb Function(s)

water leaves the tubular fluid to increase solute concentration and increase water concentration of the blood

Collecting Duct Function(s)

1. 1. ions and water move from tubular fluid to the blood, tubular fluid drains to calyces and renal pelvis - now considered urine

2. 2. bicarbonate ions and H+ are used to maintain pH of blood and urine

Distal Convoluted Tubule Function(s)

1. 1. ions (Na+) move from tubular fluid to blood

2. 2. organic wastes (acids, ammonia, drugs) move from blood into the tubular fluid

3. 3. blood volume and pressure are controlled here via sensory receptors and hormones

Ureter

the tube that transports urine from the kidney to the bladder

Peristalsis

the smooth muscle contractions that propel urine through the ureters

Transitional Epithelium

the epithelial tissue that changes shape to accommodate changes in urine volume

Lamina Propria

the connective tissue underlying the transitional epithelium

Muscularis

the smooth muscle layer of the ureter responsible for peristalsis

Adventitia

the fibrous outer tissue later containing loose areolar connective tissue and blood vessels

Trigone

the triangular region at the floor of the bladder

Detrusor Muscle

the smooth muscle layer of the bladder responsible for contractions during urination

Submucosa

connective tissue layer that contains elastin fibers within the bladder wall

Internal Urethral Sphincter

the involuntary sphincter that controls urine discharge from the bladder

External Urethral Sphincter

the voluntary sphincter responsible for controlling the release of urine

Urethral Orfice

the opening through which urine exits the urethra into the environment

Prostatic Urethra

the portion of the male urethra associated with the prostate gland

Membranous Urethra

the middle (intermediate) section of the male urethra

Penile (Spongy) Urethra

the portion of the male urethra that travels through the penis

Micturition Reflex

the dual involuntary and voluntary reflex that stimulates urination

Incontinence

the inability to control micturition (urination)

Retroperitoneal

describes the position of the ureters behind the peritoneum

Urinary System Function(s)

• filters waste products from the blood

• produces urine to remove waste products

• maintains water balance in the body

• regulates electrolyte levels

• helps control BP

• maintains acid base pH

• stores urine in the bladder temporarily till it is eliminated

Organs of the Urinary System

• kidney

• ureters

• urinary bladder

• urethra

Kidney

filters blood and produce urine

Urinary Bladder

stores urine till it is released

Urethra

carries urine from the bladder out of the body

Vessels of the Urinary System

• renal arteries

• renal veins

• afferent arterioles

• efferent arterioles

Renal Arteries

carry oxygen - rich blood to the kidneys

Renal Veins

carry filtered blood away from the kidneys

Afferent Arterioles

bring blood to the glomeruli for filtration

Efferent Arterioles

carry blood away from the glomeruli

3 Tissues That Hold Kidney In Situ

1. Renal Capsule

2. Adipose Tissue

3. Renal Fascia

Renal Capsule

thin tough layer that protects the kidney and helps maintain its shape

Adipose Tissue

layer of fatty tissue surrounding the renal capsule which cushions the kidneys and helps hold it in position

Renal Fascia

outer layer of the dense connective tissue that anchors the kidney to surrounding structures which helps prevent movement of the kidneys within the abdominal cavity

Nephron

basic functional unit of the kidney

Glomerulus

filter water, wastes, and small molecules from the blood while preventing blood cells and large proteins from leaving the bloodstream

Bowman’s Capsule

surrounds the glomerulus, collects the filtrate produced during blood filtration

Loop of Henle

descending limb reabsorbs water; ascending limb reabsorbs salts (sodium and chloride) concentrates urine and conserves water

Normal Urine Compositions

water, creatinine, uric acid, ammonia, urea

Abnormal (unhealthy) Urine Compositions

glucose, protein, blood cells

Ureters 3 Layers (deepest to superficial)

• Mucosa

• Muscularis

• Adventitia

Male Urethra

both reproductive and urinary functions, longer urethra, 3 regions

Female Urethra

shorter urethra, only urinary functions

Nephroptosis

kidney droops from its normal position

Renal Sinus

internal cavity, surrounds pelvis, holds adipose tissue

Renal Cortex

outermost region of the kidney

Renal Medulla

deeper inner region of the kidney

Renal Pelvis

central collecting region

Renal Pyramid

conical mass of tissue, forms part of the renal medulla

Renal Column

bands of cortical tissue that separate adjacent pyramids

Parietal Layer

the outer, simple squamous epithelial layer of the Bowman’s capsule

Podocytes

specialized cells w/ “feet” that wrap around glomerular capillaries and help form filtration slits

Visceral Layer

inner layer of Bowman’s capsule, made of specialized cells

Main Components of the Nephron

renal corpuscle and renal tubule