3.5 Taking out the 'rubbish'- 2

• Biology
• Middelbare school
• vwo
• Leerjaar 3

Learning objectives: 'what I am going to learn'

I can .... 

• name the excretory organs of the human body and their excretory products
• describe how kidneys function
• explain what happens with your health if your kidneys do not work properly

New key terms:

excretory - excretion - kidneys - ureter - bladder - urethra - renal artery / vein - reabsorption - filtration - dialysis - urea 

assigments

read first your (digital) book button C and D

summarise their content and learn it

(show the summary to your teacher)

do excercise 1-3

1. put in the correct order -> 2. check with info in your summary

1. The urine is transported to the bladder along tubes called ureters.
2. Blood is brought to the kidney in the renal artery which branches off the aorta
3. The purified blood returns to the circulation through the renal vein and to the heart through the vena cava.
4. The bladder stores the urine until it is convenient to expel it from the body through the urethra.
5. The kidney regulates/controls the water and salt content and removes urea.
6. The filtered excess water, salts and urea form a liquid called urine

2-5-6-1-4-3

nephron

The kidney is packed with around a million structures called nephrons. These nephrons start in the cortex of the kidney and loop down into the medulla and back to the cortex.

The nephron regulates the level of water, and salts and removes urea from the blood.

The Bowman’s capsule (renal capsule):

surrounds a ball of capillaries called the capillary knot

high pressure is created in the capillary knot by the diameter of the capillary leaving the knot being narrower than the capillary entering

this pressure results in ultrafiltration where water, salts, glucose, and other small molecules pass out of the capillary and into the Bowman's capsule

proteins and blood cells are too big to leave the capillaries to go into the tubule

The rest of the tubule is responsible for the selective reabsorption of glucose, some salts, and lots of the water.

The collecting duct is responsible for the selective reabsorption of water and for sending urine to the ureter.

kidneys

functions: by filtering out and reabsorption of water, salts and urea 

• regulate the water content of the blood
• excrete waste products* of cell metabolism 

*urea= nitrogen-containing substance, which is the product of the breakdown of excess of amino acids in the liver

urine= liquid which leaves the kidneys and consists of excess water, urea and salts 

watch the informative video

where in the human body is urea produced?

1. kidneys
2. liver

a person with malfunctioning kidneys must adjust his/her daily food intake.
(s)he must reduce the intake of ....

1. carbohydrates
2. fats
3. proteins
4. vitamins and minerals

the process a dialysis machine is based on, is

1. diffusion
2. filtration
3. reabsorption

compare dialysis with kidney transplant. Name one aspect by which kidney transplant is prefered.

homework 

next two lessons: review

* 3 posters - in pairs - no device/book/note book - bring colour pencisl 

* learn paragraph per paragraph 

--> TEST (for a mark) : Tuesday 07 October - 3rd period