Year 11 Biology: Kidneys Homeostasis in Action

What Are Kidneys?

The kidneys are two small, bean-shaped organs located in your lower back. They play a crucial role in keeping your body healthy. Their main job is to filter waste products from the blood and help maintain the balance of fluids and minerals in your body.

What Is Homeostasis?

Homeostasis is the process your body uses to keep everything balanced and stable, even when things outside change. Think of it like a thermostat that keeps your home at a comfortable temperature. Your body needs to control things like temperature, pH levels, and the amount of water and salts.

How Do Kidneys Help with Homeostasis?

The kidneys help maintain homeostasis by:

1. Filtering Blood: They remove waste substances from the blood, such as urea (a waste product from protein breakdown), and excess salts and water.
2. Regulating Water Levels: If you drink a lot of water, your kidneys will produce more urine to get rid of the excess. If you’re dehydrated, they will conserve water and produce less urine.
3. Balancing Minerals: The kidneys help control the levels of minerals like sodium and potassium in your body. This balance is important for your muscles and nerves to work properly.

How Do Kidneys Work?

1. Filtration: Blood enters the kidneys through the renal artery. Inside the kidneys, there are tiny units called nephrons that filter the blood.
2. Reabsorption: As the blood passes through the nephrons, useful substances like glucose and some water are reabsorbed back into the bloodstream.
3. Secretion: Waste products and extra substances are secreted into the urine.
4. Excretion: The urine then travels to the bladder and is expelled from the body when you go to the toilet.

Key Rules for Understanding Kidneys and Homeostasis

1. Kidneys filter blood to remove waste.
2. They help control water levels in the body.
3. They balance important minerals.
4. Homeostasis keeps your body stable.

Tips and Tricks

• Think of the Kidneys as Cleaners: They clean your blood and keep your body balanced.
• Visualise the Process: Draw a diagram of the kidney, labelling parts like the renal artery, nephron, and bladder. This helps you remember how blood flows through the kidneys.
• Relate to Everyday Life: Consider how you feel after drinking a lot of water or when you are dehydrated. This shows how the kidneys respond to changes in your body.

Questions

Easy Level Questions

1. What shape are the kidneys?
2. How many kidneys do humans have?
3. What do the kidneys filter from the blood?
4. What is the waste product made from protein breakdown?
5. What is homeostasis?
6. Name one mineral the kidneys help regulate.
7. What happens to your urine when you drink a lot of water?
8. What is the name of the tiny units in the kidneys?
9. What organ stores urine before it is expelled?
10. What do the kidneys do when you are dehydrated?
11. Why is it important to balance minerals in the body?
12. What blood vessel carries blood to the kidneys?
13. What is reabsorption in the kidneys?
14. What does the body do with excess salts?
15. How do kidneys help with temperature control?
16. What is the main function of the renal artery?
17. What do kidneys do with glucose?
18. What organ do you use to get rid of urine?
19. How does the body react to high salt intake?
20. What is the role of the bladder?

Medium Level Questions

1. Describe the process of filtration in the kidneys.
2. How do kidneys help maintain blood pressure?
3. Explain how kidneys respond to dehydration.
4. What happens to waste products after they are filtered?
5. How do the kidneys help control blood pH?
6. Why is it important for kidneys to reabsorb water?
7. What happens if the kidneys cannot filter blood properly?
8. How does urine formation occur step by step?
9. What is the difference between filtration and reabsorption?
10. How can exercise affect kidney function?
11. How do kidneys contribute to the balance of electrolytes?
12. What is the significance of the renal vein?
13. How do the kidneys communicate with the brain?
14. What lifestyle choices can affect kidney health?
15. Explain the role of hormones in kidney function.
16. How does the body know when to release more urine?
17. What factors can lead to kidney disease?
18. Why is hydration important for kidney function?
19. What can happen if you drink too little water?
20. How do kidneys help during heavy exercise?

Hard Level Questions

1. Describe the structure of a nephron in detail.
2. How does the process of osmosis relate to kidney function?
3. Explain how the kidneys maintain acid-base balance in the body.
4. What are the consequences of an imbalance of potassium levels?
5. How do kidneys filter blood without losing essential nutrients?
6. Discuss the effects of high blood pressure on kidney function.
7. What role do kidneys play in hormone regulation?
8. Explain the concept of glomerular filtration rate (GFR).
9. How does kidney failure affect other body systems?
10. What are the primary differences between acute and chronic kidney disease?
11. How do the kidneys respond to a high-protein diet?
12. What is the significance of the counter-current multiplier system?
13. How can kidney stones form, and what are their effects?
14. Describe the relationship between the kidneys and the urinary system.
15. How can diabetes affect kidney health?
16. What technological advances have improved kidney treatments?
17. Discuss the ethical considerations of kidney transplants.
18. How do kidneys adapt to changes in diet or environment?
19. Explain the feedback mechanisms involved in kidney function.
20. What research is currently being done on kidney diseases?

Answers and Explanations

Easy Level Answers

1. Bean-shaped.
2. Two.
3. Waste substances.
4. Urea.
5. The process of keeping the body stable.
6. Sodium or potassium.
7. It produces more urine.
8. Nephrons.
9. The bladder.
10. It conserves water.
11. To keep muscles and nerves functioning properly.
12. The renal artery carries blood to the kidneys.
13. Reabsorption is when useful substances are taken back into the blood.
14. They are excreted in urine.
15. It helps with temperature balance by influencing blood flow.
16. To supply blood to the kidneys.
17. They reabsorb it to keep energy.
18. The bladder expels urine.
19. The kidneys will conserve water.
20. It stores urine.

Medium Level Answers

1. Blood is filtered through nephrons, where waste is removed.
2. They regulate fluid volume, which can affect blood pressure.
3. They conserve water and produce less urine.
4. They are sent to the bladder to be excreted.
5. They regulate bicarbonate and hydrogen ions.
6. To prevent dehydration and maintain blood volume.
7. Waste accumulates, leading to health issues.
8. Filtration, reabsorption, secretion, and excretion.
9. Filtration is removing waste; reabsorption is taking back useful substances.
10. It can enhance kidney perfusion and filtration.
11. They balance levels of sodium, potassium, and calcium.
12. It carries filtered blood back to the heart.
13. Hormones like ADH regulate water reabsorption.
14. Poor diet can lead to kidney strain.
15. Hormones like aldosterone affect kidney function.
16. Kidneys can signal when to conserve or release fluids.
17. Conditions like diabetes or hypertension can harm kidneys.
18. It ensures they function properly and efficiently.
19. Hormones and neural signals adjust kidney activity.
20. Research on dialysis, transplant techniques, and genetic disorders.

Hard Level Answers

1. A nephron consists of a glomerulus, Bowman’s capsule, and tubules.
2. Osmosis helps in reabsorbing water in the kidneys.
3. They balance acids and bases by filtering and reabsorbing.
4. High potassium can lead to heart problems.
5. They selectively filter to keep nutrients while removing waste.
6. High blood pressure can damage kidney arteries and function.
7. They regulate hormones like erythropoietin for red blood cell production.
8. GFR measures how well kidneys filter blood.
9. It can cause fluid overload and affect other organs.
10. Acute is sudden; chronic is long-term damage.
11. It increases the load on kidneys, affecting function.
12. It helps concentrate urine and conserve water.
13. They form from calcium and other substances crystallizing.
14. They work together to filter blood and excrete waste.
15. High blood sugar can damage blood vessels in kidneys.
16. Advances include improved dialysis machines and transplant techniques.
17. There are considerations about donor rights and organ allocation.
18. They adjust to conserve or excrete necessary substances.
19. Feedback mechanisms regulate kidney function based on body needs.
20. Research is focused on prevention, treatment, and new technologies.

This structured approach should help you understand how kidneys work and their vital role in maintaining homeostasis in your body!