Urinary System

Functions of the Urinary System

• Primary: Elimination of waste products:– Nitrogenous waste– Toxins– Drugs

• Secondary: Regulate homeostasis– Water balance– Electrolytes– Acid-base balance– Blood pressure– RBC formation

Organs of Urinary System

• Kidneys• Ureters• Urinary Bladder• Urethra

Location of Kidneys

Kidney RegionsRenal cortex—outer regionRenal medulla—inside the cortexRenal pelvis—inner collecting tube

Kidney Structures

• Renal or medullary pyramids—triangular regions of tissue in the medulla

• Renal columns—extensions of cortex-like material inward that separate the pyramids

• Calyces—cup-shaped structures that funnel urine towards the renal pelvis

Kidney Functions• One-quarter of the total blood supply of the body passes

through the kidneys each minute• Renal artery provides each kidney with arterial blood

supply• Renal artery divides into segmental arteries interlobar

arteries arcuate arteries cortical radiate arteries

Nephrons

• The structural and functional units of the kidneys

• Responsible for forming urine

• Main structures of the nephrons– Glomerulus– Renal tubule

Nephrons

• Glomerulus – Knot of capillaries– Capillaries are covered

with podocytes from the renal tubule

– Glomerulus sits within a glomerular (Bowman’s) capsule (the first part of the renal tubule)

Nephron

• Renal tubule extends from glomerular capsule and ends at the collecting duct– Glomerular

(Bowman’s) capsule– Proximal convoluted

tubule (PCT)– Loop of Henle– Distal convoluted

tubule (DCT)

Falling systemic bloodpressure volume

Reduced filtrate volumeor solute content in renaltubules

JG cells of kidneys

(+)(+)

(+)

(+)

(+)

(+)

(+)

(+) (+)

(+)

(+) = stimulates

Renin-angiotension system

Neural regulation (sympatheticnervous system effects)

Effects of ADH release

Renin

Release

Leads to

Angiotensin IIformed in blood

Systemic arterioles

Vasoconstriction

Peripheral resistance

Adrenal cortex

Aldosterone

Kidney tubules

Na+ reabsorption (andH2O absorption)

Blood volume

Rising blood pressure

Causes

Results in

Secretes

Targets

Causes

Results in

Causes

Results inCauses

Releases

Inhibits baroreceptorsin blood vessels

Sympathetic nervoussystem

Systemic arterioles

Vasoconstriction

Peripheral resistance

Hypothalamicosmoreceptors

Posterior pituitary

ADH (antidiuretichormone)

Collecting ductsof kidneys

H2O reabsorption

KEY:

• Urinary System Video• http

://video.about.com/surgery/Kidney-Transplant.htm

• http://animal.discovery.com/videos/river-monsters-fish-swims-up-urine-stream.html

• http://animal.discovery.com/videos/weird-true-freaky-fish-attacks-mans-urethra.html

Kidney Transplant Video

• http://www.orlive.com/sentara-profile/videos/living-donor-kidney-transplant-surgery1

• https://www.youtube.com/watch?v=ou8CC4XN9wk