The Urinary SystemThe Urinary System

The Urinary SystemThe Urinary System

• The Urinary System consists of The Urinary System consists of – The kidneys (and blood vessels entering The kidneys (and blood vessels entering

and leaving them)and leaving them)– The uretersThe ureters– The bladderThe bladder– The urethraThe urethra

http://en.wikibooks.org/w/index.php?title=File:Anatomy_and_physiology_of_animals_Positions_os_organs_of_the_urinary_system_in_a_dog.jpg&filetimestamp=20071126010225

• Renal ArteriesRenal Arteries– Carries blood into the kidneys. This blood Carries blood into the kidneys. This blood

contains excess water and salts, along with contains excess water and salts, along with urea which was made in the liverurea which was made in the liver

• KidneysKidneys– Removes excess water, salts and urea from Removes excess water, salts and urea from

the blood. These compounds combine to the blood. These compounds combine to form urineform urine

• Renal VeinsRenal Veins– Takes blood away from the kidneys back to Takes blood away from the kidneys back to

the heart. This blood contains no waste the heart. This blood contains no waste materialmaterial

• UretersUreters– Tubes which carry urine from the kidney to Tubes which carry urine from the kidney to

the bladderthe bladder

• BladderBladder– Stores the urine until it can be released Stores the urine until it can be released

from the bodyfrom the body

• UrethraUrethra– The tube which takes urine from the The tube which takes urine from the

bladder and out of the bodybladder and out of the body

OB20 OB20 understand the understand the structurestructure and function of the urinary and function of the urinary system: system: bladder, renal artery, renal vein, ureter, urethra and bladder, renal artery, renal vein, ureter, urethra and kidneykidney

bladder

urethra

bladder

renal artery

renal vein

ureter

urethra

kidn

ey

OB20 OB20 understand the understand the structurestructure and and functionfunction of the urinary of the urinary system: system: bladder, renal artery, renal vein, ureter, urethra and bladder, renal artery, renal vein, ureter, urethra and kidneykidney

bladder

urethra

renal vein carries blood from kidney

renal artery carries blood to kidney

kidney filters blood to remove urea

ureter transports urine to bladder

bladder stores urine

urethra releases urine

A. Renal A. Renal veinvein

1. releases urine1. releases urine

B.B.UreterUreter 2. carries blood to kidney2. carries blood to kidney

C.C. BladderBladder 3. filters blood to remove 3. filters blood to remove ureaurea

D.D.KidneyKidney 4. transports urine to bladder4. transports urine to bladder

E.E. UrethraUrethra 5. stores urine5. stores urine

F. Renal F. Renal arteryartery

6. carries blood from kidney6. carries blood from kidney

Match the following parts of the Urinary system with their function:

The KidneyThe Kidney

1. Blood containing water, salts and urea enters the kidney

2. Urea, some salts and water are removed from bloodstream by kidney and form urine

3. Urine leaves the kidney in the ureter

OB23 OB23 recall that waste products are removed from the bloodstream recall that waste products are removed from the bloodstream by by filtration in the kidneys in the form of urine, which contains filtration in the kidneys in the form of urine, which contains urea, urea, water and saltswater and salts

watersalt

urea

1 blood containing water, salts and urea enters the

kidney

2 urea, some salts and water are removed

from bloodstream by kidney and form urine

3 the urine leaves the kidney in the ureter

C. blood containing water, salts and urea enters the kidney

B. urea, some salts and water are removed from bloodstream by kidney and form urine

A. the urine leaves the kidney in the ureter

Rewrite the following stages of filtration in the kidneys in the order that they occur in the body:

OB23 OB23 urine is stored in the bladder before being released from the urine is stored in the bladder before being released from the bodybody

urethra

A section through the kidney shows an outer darker region(cortex) and a lighter inner zone (medulla).

Cortex

Medulla

Pelvis

Ureter

– – Identify Cortex, Medulla, Pelvis, UreterIdentify Cortex, Medulla, Pelvis, Ureter

A = Cortex B = Medulla D = PelvisC = Ureter

A

B

C

D

LEARNING CHECK

As urine is produced, it flows into the renal pelvis, then into theureter, to the bladder.

The kidneys work by filtering the blood and then absorbingback what the body needs to keep. The wastes are allowedpass to the bladder, for storage and release.

Reabsorption

Filtration

Cortex

Medulla

Ureter

Pelvis

Filtration—In the outer cortex, small molecules like glucose,amino acids, water, urea and salts filter out of the blood intonarrow tubules.

Reabsorption—blood vessels reabsorb back useful nutrients from the tubules. Urea, excess salts and water, are allowed to continue down the tubule and on to the bladder.

Secretion is the production and release of chemicals from cells.

Some substances, especially potassium and hydrogen ions, are secreted from the blood into the tubule in the cortex region.

When the blood becomes too acidic, hydrogen ions are secreted into the urine.

By controlling the hydrogen ion concentration in the blood, the kidneys control blood pH.

Land animals have a continuous need to conserve water.

Water must be taken in daily and its loss must be carefully regulated.

Water is taken in as food and drink, and is also formed inside the cells during some reactions, especially respiration.

Homeostasis – Water Levels in the Body

Water is lost from the body through our lungs, skin, intestines and kidneys.

Water is lost from the body through a number of ways:

Lungs – some water gets evaporated as we exhale from our warm, damp lungs.

Skin – by evaporation from cells and through sweat.

Intestines – in the faeces (undigested food).

Kidneys – in dissolving the poisons and wastes we wish to excrete from the body.

We have no control over the amount of water lost each day from the lungs, skin or intestines.

So the kidneys are the water control (osmoregulatory) organs of the body – conserving or eliminating water as the body requires.

Renal DiseaseRenal Disease

• Due to damage of the kidneysDue to damage of the kidneys

• 2 kinds2 kinds– AcuteAcute

• Caused by trauma, severe dehydration or circulatory Caused by trauma, severe dehydration or circulatory failurefailure

• Signs include vomiting, Urea in blood, Lethargy and Signs include vomiting, Urea in blood, Lethargy and DiarrhoeaDiarrhoea

• Treatment involves fluid therapy and dialysisTreatment involves fluid therapy and dialysis

– ChronicChronic• Caused abnormalities in the kidney or metabolic disordersCaused abnormalities in the kidney or metabolic disorders

• Occurs over a long period of time. Signs are same as Occurs over a long period of time. Signs are same as AcuteAcute

• Treatment in involves solving the original causeTreatment in involves solving the original cause