The document provides information about the human kidney and its functions. It discusses the three main parts of the kidney - the cortex, medulla, and pelvis. It also outlines two key functions of the kidney: filtration of urine from blood and osmoregulation to maintain salt and water concentrations. Students are asked to watch a video, answer questions about the kidney parts and functions, and draw a labelled diagram of a kidney section.

1. GRADE 8 BIOLOGY
LESSON 1

2. WEEK 12 Task
 Click on the link given with the tasks to open them.
 Watch and listen the video carefully.
https://www.youtube.com/watch?v=rT_vjf5fMw4
Read the following questions, think for answer and then write answer on your
Biology notebook.
Q1: What are the two functions of human kidney?
Q2: Enlist the three parts of the kidney.
Q3: Draw a labelled diagram of a section through a kidney.

3. Dear students at the end of the
lesson you will be able to;
• identify different parts of
human kidney.
• write functions of human
kidney.
.

5. Do u remember???
 What is excretion?
 Difference between excretion and
defecation?
 What are main excretory organs
in man?
 What are the components of
urinary system?

6. EXCRETION
It is the removal of waste
products formed as a result
of chemical reaction inside
a living organisms

7. DEFECATION
It is the removal of faeces
from the body.
The faeces, the solid
indigestible part of the food
we eat, are not waste
chemicals and they have not
been made inside the body

9. Components of
Urinary System
 Pair of kidneys
 Pair of ureters
 A urinary bladder
 Urethra

11. 11 11

12. HUMAN KIDNEYS
 Kidneys are dark-red, bean
shaped organs.
 They are situated under
your ribs in your back on
either side of vertebral
column.
 Left kidney is little higher
than the right.

13. HUMAN KIDNEY
 Each kidney is about
11.5cm long, 6cm wide and
3.5cm thick.
 Each kidney weighs about
140gm.
 Kidney is surrounded by
fatty case or capsule.

14. PARTS OF
HUMAN KIDNEY
Human kidney consists of
three parts:
 Cortex
 Medulla
 Pelvis

15. CORTEX
 It is the outer part of the
kidney.
 It is dark red in color due to
the presence of knot of
blood capillaries.

16. MEDULLA
 It is the inner part of the
kidney.
 It is pale red in color.
 Medulla consists of several
cone shaped areas called
pyramids.

17. PELVIS
 Pyramids project into a
funnel shaped cavity called
pelvis.
 Pelvis is the base of the
ureter.

18. HILUS
 The concave side of the kidney
faces the vertebral column.
 Depression near the centre of
the concave area of the kidney
is called hilus.
 Through hilus, ureter leaves
the kidney and blood vessels
and nerves enter and leave
kidney.

19. GRADE 8 BIOLOGY
LESSON 2

20. FUNCTIONS OF
HUMAN KIDNEY
 Filtration of urine from blood.
 Osmoregulation i.e to maintain
concentration of salts and
water in the body.

21. COMPOSITION OF
URINE
 The liquid which leaves the
kidneys as urine contains:
 96% water
 4% salts and urea

22. DO YOU KNOW???
 All your blood passes through
your kidneys every five minutes.
 During the course of a day, the
kidneys remove over 200 liters of
liquid.
 Over 99% of this liquid is returned
to the blood and only about 1.5
litres passes out as urine.