2. What is the excretory system?
The excretory system is a system that removes excess,
unnecessary materials from an organism (i.e. humans),
in order to prevent damage to the body. It is
responsible for the elimination of the waste
products as well as other liquid and gaseous wastes, as
urine and as a component of sweat and exhalation.
3. Why is it important?
As we have seen, it is important in
order to prevent damage to the body:
Waste products must be removed from the
body. If they are not, they will increase in
concentration and may interfere with, or
damage cells. Waste products that must be
removed include carbon dioxide and urea.
Vocabulary:
Waste products- productos de desecho
Interfere with- interferir con
Damage- dañar
Urea- la urea
Concentration- la concentración
Cells- las células
4. WATER IN THE BODY
Water is gained
• from drinking
• from water contained in food
• from chemical reactions in the
body
Water is lost
• as sweat
• as water vapour when breathing
out
• in urine
6. Urea- the process. Part One
• Blood is brought to the kidney in the renal
artery. The kidneys filter the blood and then
reabsorb useful materials such as glucose.
After it has been purified, the blood returns to
the circulation through the renal vein.
Vocabulary:
Renal artery- las arterias renales
To filter- filtrar
Reabsorb- reabsorber
Glucose- la glucosa
To purify- purificar
Circulation- la circulación
Renal vein- las venas renales
7. Urea- the process. Part Two
Urine is taken from the kidneys to
the bladder by the ureters. The bladder stores
the urine until it is convenient to expel it from
the body.
Vocabulary
Bladder- la vejiga
To store- almacenar
Expel- expulsar
8. What’s the difference?
Note that ‘ureter’ differs
from the word ‘urethra’.
The ureters are tubes that
carry urine from the
kidneys to the bladder,
whereas the urethra is the
tube that carries urine out
of the body.
11. How does it work?
• The skin is made up of an outer layer called
the epidermis and an inner layer called the
dermis
• The skin contains sweat glands that excrete
perspiration through skin pores. Perspiration is
made up of wastes (urea), salts, and water.
Vocabulary
Sweat glands- las glándulas sudoríparas
Pores- los poros
Epidermis- la epidermis
Dermis- la dermis
