1. The Excretory System

2. Excretion

3. Learning Objectives
OB20 Understand the structure and function of the urinary system: the bladder, renal artery, renal vein, ureter, urethra and kidney
OB21 Name the products of excretion: CO2, water and urea
OB22 Understand the function of the skin in the excretion of waste products made in the body
OB23 recall that waste products are removed from the bloodstream by filtration in the kidneys in the form of urine, which contains urea, water and salts, and that urine is stored in the bladder before being released from the body
Above are the learning objectives as outlined in the Junior Cert Syllabus

4. Excretion What is excretion ?
Process by which the body removes toxic waste substances that have been produced by the body
Toxic substances are poisonous and can harm the cells of the body if not removed
If the toxic substances, which have been produced as a by-product of the body are not removed they are poisonous and can harm the body’s cells

5. What are the organs of excretion ?
Lungs
Kidneys
Skin
section of skin
sweat gland
blood capillaries
pore

6. Organs of Excretion 1 Lungs
Excrete CO2 (Carbon Dioxide) and H2O (Water)
Process called respiration
The CO2 and H20 are by-products of cellular respiration and are breathed out by the lungs. To revise the respiration link please clink on the hyperlink. o c o H o c o H

7. Organs of Excretion 2 Skin Excretes H2O and salts as sweat
Sweat also helps cool down the body when it evaporates
section of skin
sweat gland
blood capillaries
pore
Sweat is removed from the skin via the sweat ducts, as well as salts and water sweat also contains a small concentration of urea.
When temp of body raised sweat acts as a cooling factor on the skin

8. Organs of Excretion 3 Kidneys Excrete H2O, salts, and urea
Urea is made when excess protein is broken-down
H2O, salts, and urea = urine
Kidneys are part of the urinary system. Urea is produced by the breakdown of excess protein in the liver. Urine has the same components of sweat but the urea is at a higher concentration.

9. Location of kidneys Humans have two kidneys
They are located in the abdominal cavity, towards the back
They are protected by fatty tissue.
Humans have two kidneys. They are bean-shaped organs, approximately 11.5 cm long, situated in the abdominal cavity, just below the ribcage, one on either side of the spine. They are embedded in fatty tissue for protection.

10. Kidney Fatty tissue surrounds the kidney’s Why?
To protect the kidneys and insulate them
As the kidney has no bones surrounding them they require the fatty tissue to act as a shock absorber.

11. Learning Check What are the 3 main organs of excretion?
Lungs, Kidneys, Skin
Take down the box below and complete :
Organ
Substance Excreted
Lungs
Kidneys
Skin
Carbon dioxide, water vapour
Water, salts , urea
Water and salts

12. The function of the urinary system is to make and excrete urine
Clink on “Urinary system” to access hyperlink to site on the urinary system. (Internet connection required). Urea is filtered from the blood in the kidneys, carried to the bladder for storage via ureter, then excreted from body via urethra.

13. Urinary System function renal artery renal vein kidney ureter bladder
urethra
renal artery
renal vein
kidney
function
ureter
bladder
urethra
sphincter muscle

14. Renal Arteries Renal arteries carry blood to the kidney
This blood contains excess water and salts along with urea
bladder
urethr

15. Renal Vein
Renal vein takes blood from kidneys and carry it towards the heart
No waste material is present in this blood
bladder
urethr

16. Kidneys These remove excess water, salts and urea
What do these 3 combine to form?
Urine
bladder
urethr

17. Formation of Urea Urea Liver Excess Protein from food
Amino acids are the simplest form of protein and cannot be stored in the body and therefore need to be removed via excretion
Urea
Liver

18. Problems with Liver
Jaundice is a yellow discolouration of the skin and membranes
It happens when the liver cannot get rid of a yellow pigment that is normally excreted in the bile
Amino acids are the simplest form of protein and cannot be stored in the body and therefore need to be removed via excretion

19. Ureters Ureter 2 e’s = 2 tubes
These tubes carry urine from the kidneys to the bladder
Ureter Vs Urethra
Ureter
2 e’s = 2 tubes
bladder
urethr
2 of these
1 of these

20. Bladder This stores urine until it can be released from the body
Storage bag for urine
bladder
urethr

21. Bladder
If problems with bladder control a urine bag may be installed outside of the body
This is then emptied manually

22. Urethra
This is a tube which takes the urine from the bladder to the outside of the body
Sphincter muscle controls the opening and closing of the urethra
bladder
urethr

23. Urinary System Recap function renal artery carries blood to kidney
bladder
urethra
renal artery carries blood to kidney
renal vein carries blood from kidney
kidney filters blood to remove urea
function
ureter transports urine to bladder
bladder stores urine
urethra releases urine
sphincter muscle controls fluid release

24. Kidney Blood enters kidney through renal artery
Kidney filters the blood removing waste products
Main waste products : Water , salts and urea
bladder
urethra
Clink on “Urinary system” to access hyperlink to site on the urinary system. (Internet connection required). Urea is filtered from the blood in the kidneys, carried to the bladder for storage via ureter, then excreted from body via urethra.

25. Kidney
bladder
urethra
These dissolve to make urine, this passes from the kidney to the bladder through the ureter, here it is stored until its excreted
Filtered blood then leaves the kidneys through the renal vein

26. nephron
Blood enters
and leaves here
Urine leaves here

27. Bisected Kidney

28. Renal Cortex
Renal Medulla
Renal Pelvis
Ureter

29. Kidney disease
Diabetes causes damage to the small blood vessels in the kidneys.
This process slowly destroys the filters and causes problems due to build-up of the waste products in the blood.
The filters start to leak out too much protein into the urine and this can be the first sign of diabetic kidney disease.

30. Kidney disease (2)
High blood pressure can also cause kidney damage itself.
Kidney disease may also result from infection, drugs and kidney stones while some types may run in the family.

31. Treating kidney failure
1. Kidney dialysis
This is the process of removing waste and excess fluid from the blood using an artificial kidney machine that filters or washes the blood.
Blood is collected from a vein in the arm and passes along a tube that is semi-permeable.
The dialysis solution on the other side of the tube has no urea so urea passes out of the blood.
Treatment is required three times a week, each lasting about five hours.

32. Kidney Failure Kidney failure prevents toxic substances being excreted
Dialysis removes blood, filters it and returns it to the body
What causes acute renal failure?
Acute renal failure has three main causes:
A sudden, serious drop in blood flow to the kidneys. Heavy blood loss, an injury, or a bad infection called sepsis can reduce blood flow to the kidneys. Not enough fluid in the body (dehydration) also can harm the kidneys.
Damage from some medicines, poisons, or infections. Most people don't have any kidney problems from taking medicines. But people who have serious, long-term health problems are more likely than other people to have a kidney problem from medicines. Examples of medicines that can sometimes harm the kidneys include:
Antibiotics, such as gentamicin and streptomycin.
Pain medicines, such as aspirin and ibuprofen.
Some blood pressure medicines, such as ACE inhibitors.
The dyes used in some X-ray tests.
A sudden blockage that stops urine from flowing out of the kidneys.Kidney stones, a tumor, an injury, or an enlarged prostate  gland can cause a blockage.
You have a greater chance of getting acute renal failure if:
You are an older adult.
You have a long-term health problem such as kidney or liver disease,diabetes , high blood pressure, heart failure, or obesity.
You are already very ill and are in the hospital or intensive care (ICU). Heart or belly surgery or a bone marrow transplant can make you more likely to havekidney failure.
What are the symptoms?
Symptoms of acute renal failure may include:
Little or no urine when you urinate.
Swelling, especially in your legs and feet.
Not feeling like eating.
Nausea and vomiting.
Feeling confused, anxious and restless, or sleepy.
Pain in the back just below the rib cage. This is called flank pain.

33. Artery
Vein
Blood in
Blood out
Fresh dialysis fluid
Used dialysis fluid
Constant temp.
Dialysis fluid

34. Treating kidney failure
2. Kidney transplantation
A kidney transplant may be considered if your doctor feels that your general health is good enough to stand up to the operation.
You also need drugs to suppress the immune system after surgery. This is needed to stop rejection of the foreign tissue.

36. A donor kidney can come from a living person (usually a blood relative such as a parent, brother, sister or child).
Or, from someone who has died in hospital and permission has been given to use their kidneys.
The transplant kidney is placed in the groin. Your own kidneys are not removed.
After a transplant the person no longer needs dialysis.

37. Advantages of Transplants
Have a normal lifestyle as no dialysis.
Dialysis takes several hours in hospital three times a week and makes a person very tired.
Dialysis machines are expensive.

38. Disadvantages of Transplants
A good tissue match is needed for the donor kidney to reduce rejection.
Very expensive operation.
Risk of rejection of the donor kidney so immunosuppressant drugs must be taken daily.
Some religions do not allow transplants.

40. Newspaper artice: http://www. siliconrepublic

41. Mobile App

42. Dialysis patients in Ireland

44. Kidney transplants in Europe

47. All organ transplants in Europe

48. Kidney
Liver
Heart
Lung
Pancreas
Small Bowel

49. Learning Check What blood vessel carries blood to the kidneys
Renal artery
What happens the blood in the kidneys?
It is filtered
What is urine made up from
Urea, water and salts
Where is the urine then stored?
In the bladder

50. Excretion

51. Learning Objectives
OB20 Understand the structure and function of the urinary system: the bladder, renal artery, renal vein, ureter, urethra and kidney
OB21 Name the products of excretion: CO2, water and urea
OB22 Understand the function of the skin in the excretion of waste products made in the body
OB23 recall that waste products are removed from the bloodstream by filtration in the kidneys in the form of urine, which contains urea, water and salts, and that urine is stored in the bladder before being released from the body
Above are the learning objectives as outlined in the Junior Cert Syllabus

53. Kidney Dissection

54. How is CO2 formed?
Lungs take in O2 so that it can be used by the cells to get energy from food, i.e., in respiration. CO2 is a by-product of the energy production system (respiration).
Lungs take in oxygen to be used by the cells to extract energy from food

55. What are the components of sweat?
Salt & water (and a small amount of urea in some sweat glands)

56. Where are the kidneys located?
In the abdominal cavity

57. The kidney is usually covered in a layer of fat can you suggest a reason for this?
For protection.

58. Through which blood vessel of the kidney does the blood return to the heart?
Through the renal vein.

59. Urine is passed from the kidneys to the bladder through tubes called ….?
Ureters

60. The function of the bladder is to store...
Urine

61. Urine passes out of the body through a tube called the ……?
The urethra

62. What is the function of the sphincter muscle?
It controls the release of urine from the body. This is usually a voluntary action.