The document summarizes the human excretory system. It describes the kidneys, which filter waste from the blood and regulate water, acid, and mineral levels. The kidneys are bean-shaped organs located in the abdominal cavity protected by fatty layers. They remove waste through a three-step process of filtration, reabsorption, and urine formation. Urine travels from the kidneys through ureters to the bladder, where it is stored before exiting the body through the urethra. The document also includes diagrams labeling these structures and processes.

1. Excretory system

2. Most important processes
Filtration
Absorption
Distribution
Excretion

3. Urinarysystem
Kidneys
Aorta and renal
artery
Vena cava inferior
and renal vein
Urine tube - Ureter
Bladder
Urethra

4. Bean shaped
Approximately the
size of a fist, and
protected by a
fatty layer.
Situated in the
abdominal cavity,
under the
diaphragm, either
side of the spine.
Right is slightly
lower than left.

5. Functionofkidneys Excrete waste products
Regulate water in the blood
and tissue fluid.
Regulate acid and mineral salts to
ensure the body does not have a
surplus.

6. Filtration Re-absorption Formation of Urine
Blood is filtered and
waste products (urea)
are removed from the
blood.
Water, salts and other
substances are re-
absorbed. The water
that is not re-absorbed,
keeps the waste
products in solution to
be excreted later.
Blood is filtered and
waste products (urea)
are removed from the
blood.

7. Ureter
• The two tubes that transport
urine from the kidneys to the
bladder
Bladder
• The bladder stores urine
before it is excreted after a
period of time.
Urethra
• Transports urine from the
bladder out of the body.

8. Title slide: http://www.drugrehabfl.net/wp-content/uploads/2012/11/kidneys.jpg
Slide 3: http://www.pharmaworld.pk/products/gallery/gal919_t65.jpg
Slide 4: http://www.apsubiology.org/anatomy/2020/2020_Exam_Reviews/Exam_4/kidney%20anatomy.jpg
Slide 6: Nephron: https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcS1iYFwxyh0hPL-
NgaamLymga2jRKGe57lsWNlnhd-zGresPWBt Glomeruli: https://encrypted-
tbn3.gstatic.com/images?q=tbn:ANd9GcRE8Q7l-FSHxARzZRcuwrJn0npzdKOX5F_JemfaL8G2AkAkhRb2 Urinalysis:
https://classconnection.s3.amazonaws.com/588/flashcards/2797588/jpg/tripphos-144F2341C152AF08538.jpg
Slide 7: http://www.amharicdrama.com/wp-
content/uploads/2015/06/princ_rm_photo_of_urinary_tract_infection-300x335.jpg
TEXT: du Plessis et al: DocScientia Textbook and Workbook Grade 9 Natural Sciences CAPS; 2013
info@docscientia.co.za