Topic: Urinary system

Author: Elżbieta Szedzianis

Target group

7th‑grade student of the elementary school.

Core curriculum

8. Urinary system and excretion. The student:

1) shows the essence of the excretion process and gives examples of substances that are excreted from the human body (urea, carbon dioxide) and lists organs involved in their excretion,

2) identifies the elements of the excretory system (on a model, in a drawing, as described, etc.) and presents their functions.

The general aim of education

The students describe the structure and function of the urinary system.

Criteria of success

• You will show on your body where the kidneys are;

• describe how urine is formed;

• name organs that remove urine.

Methods / techniques

Conversation, work with text, work with film.

Individual and collective work.

Lesson plan overview (Process)

Introduction

1. The students solve interactive tasks individually, then they check their solutions in pairs. If they do not know the answers, they are looking for it in the e‑textbook.

After solving the tasks, the teacher asks:
Where are the unnecessary and poisonous decomposition products of nutrients formed? How do they get into the excretion organs, such as the skin and the lungs? How to find out that the skin and the lungs expel water and carbon dioxide?

2. The teacher explains the aim of the lesson and the success criteria to be achieved by the students.

Realization

1. The teacher asks the students to find answers to the questions displayed on the screen:
a. What organs does the urinary system consist of and what functions do they have?
b. Where are the kidneys?
c. What system does the urinary system work with?
d. Where is urine formed?

To do this, the students read paragraph 1 on page 3 in the e‑textbook and look at Illustration 2, and then they write down the note in the notebooks.

2. The students watch the film entitled „Structure of the kidney of a pig”.

3. The teacher asks the students to build the urinary system out of the elements.

Summary

The teacher asks the students:

• What would happen if the kidneys stopped working?

• Where is formed and what is the difference between primary and final urine?

• What chemical components are contained in urine?

• Which organs (except kidneys) perform excretory functions?

• What else do you need to learn about the urinary system so that you are happy with your knowledge?

Homework for keen students.

Make a model of the urinary system with a plastic bag, plastic tubes, a clamp, a funnel, filter paper, and adhesive tape. For this model, make the “blood” from water, kitchen salt, yellow food dye and red brocade.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Urinary system

As a result of metabolism in the cells, there are many waste materials created. These are not needed and can be damaging. These include toxic ammonia, a product of protein metabolism. It is transformed in the liver into urea. Then, along with blood it goes to the kidneys, where it reaches the urine with which it is excreted. Harmful products of metabolism and toxic substances taken with food, e.g. drugs or alcohol, first enter the liver, where they are changed into less toxic forms, and then to the kidneys and other organs that support excretion.

The kidneys, skin and lungs are involved in the removal of water. Mineral salts that are products of the body's mineral metabolism are excreted by the skin, which is why sweat has a salty taste. The removal of unnecessary and harmful metabolic products from the body is called excretion. The urinary system plays the most important role in this process.

The urinary system, also known as the excretory system, includes the kidneys and the urinary tract: the ureters, the urinary bladder and the urethra. The kidneys are even bean‑shaped organs the size of a fist, located on both sides of the spine at the height of the lumbar vertebrae. They are made of nephrons in which blood is filtered, and its filtrate is concentrated to form urine. The ureter branches off from each kidney – a long tube inside of which the urine falls into the urinary bladder where it is periodically collected. Its smooth muscle walls are flexible and expand as the urinary bladder fills. The urethra is an odd tube that is used to excrete the urine outside from the urinary bladder. It is equipped with a sphincter muscle that closes the light of the urethra and allows controlling the excretion of urine from the body. In men, the urethra is longer than in women, because it is also used to excrete semen.

The basic building and functional unit of the kidney is the nephron. It consists of a renal corpuscle (a thin‑walled capsule surrounding a dense network of capillaries) and a uriniferous tubule. Blood flows through the capillaries under high pressure. Blood plasma components such as water and substances dissolved in it, e.g. glucose, amino acids, sodium ions (NaIndeks górny +⁺) , chloride ions (ClIndeks górny -^-), go to the capsule as a result of filtration. Only the ingredients that fall into their pores get through its thin walls and the walls of the vessels. No proteins, blood cells or platelets are filtered. The filtrate formed in the capsule – primary urine – flows down to the uriniferous tubule. From here, all substances needed by the body are absorbed into the capillaries surrounding the uriniferous tubule. In the final section of the tubule, urine takes the form of final urine, which is excreted from the kidneys to the urinary bladder through the ureters.

• The urinary system, the skin and the respiratory system participate in the removal of unnecessary and harmful metabolic products from the body.

• The urinary system consists of the kidneys, ureters, urinary bladder and urethra.

• The basic building and functional unit of the kidney is the nephron.

• In the glomerulus the filtration process takes place, and in the uriniferous tubule – the process of recovering substances needed by the body.

• The filtrate of blood plasma formed in the glomerular capsule is primary urine.

• The kidneys regulate the amount of water and the concentration of mineral salts in the body.