The Excretory and Urinary System worksheet - Free Printable
Educational worksheet: The Excretory and Urinary System worksheet. Download and print for classroom or home learning activities.
JPG
1000×1291
113.5 KB
Free · Personal Use
Quality Assured by Worksheets Library Team
Reviewed for educational accuracy and age-appropriateness
ID: #1397267
⭐
Show Answer Key & Explanations
Step-by-step solution for: The Excretory and Urinary System worksheet
▼
Show Answer Key & Explanations
Step-by-step solution for: The Excretory and Urinary System worksheet
Let's solve each question step by step with clear explanations.
---
Answer:
Feces are not considered excretory waste because they consist mainly of undigested food, bacteria, and dead cells from the digestive tract — not metabolic waste products from cellular processes. Excretory waste refers to substances produced as byproducts of metabolism (like urea, carbon dioxide, and excess ions), which are removed by organs such as the kidneys, lungs, and skin. Feces are a result of digestion and elimination of indigestible material, not metabolic waste.
✔ Key Point: Excretion = removal of metabolic wastes; Egestion = removal of undigested food (feces).
---
Answer:
The lungs are considered excretory organs because they remove carbon dioxide (CO₂), a waste product of cellular respiration, from the body. During gas exchange in the alveoli, CO₂ diffuses from the blood into the air sacs and is exhaled. This process helps maintain the pH balance of the blood and eliminates a toxic metabolic byproduct.
✔ Explanation: CO₂ is a metabolic waste generated during aerobic respiration and must be removed to prevent acidosis.
---
#### a. Name the parts P, Q, R, S and T. (5 pts)
Based on the standard human urinary system diagram:
- P – Renal artery
*(Carries oxygenated blood to the kidney)*
- Q – Renal vein
*(Carries deoxygenated blood away from the kidney after filtration)*
- R – Ureters
*(Tubes that carry urine from the kidneys to the bladder)*
- S – Urinary bladder
*(Stores urine until it is expelled)*
- T – Urethra
*(Tube through which urine exits the body)*
> ✔ Note: The "sphincter muscle" labeled near T is part of the urethra, controlling the release of urine.
---
#### b. Place an X on the structure that produces urine. (1 pt)
Answer:
Place an X on the kidneys (the two bean-shaped structures at the top of the diagram).
➡️ The kidneys produce urine through the filtration of blood in the nephrons.
---
#### c. Explain the role of the sphincter muscle. (1 pt)
Answer:
The sphincter muscle (specifically the internal and external urethral sphincters) controls the release of urine from the bladder. It contracts to hold urine in the bladder and relaxes to allow urine to pass out through the urethra during urination.
✔ Function: Prevents involuntary leakage of urine and allows voluntary control over urination.
---
#### d. State ONE difference between the composition of blood in P and Q. (1 pt)
Answer:
Blood in P (renal artery) contains higher levels of urea and waste products, while blood in Q (renal vein) has lower levels of urea and waste because the kidneys have filtered them out during urine formation.
Alternatively:
- Blood in P is oxygen-rich, whereas blood in Q is deoxygenated (though oxygen levels are still relatively high due to the kidney’s high metabolic demand).
But the most relevant difference for excretion is:
👉 Urea concentration is higher in P than in Q.
✔ Best Answer: The blood in P has more urea and other metabolic wastes than the blood in Q, because the kidneys filter these substances out.
---
#### e. A sample of urine was collected from the lab. It contained water, sugar, proteins, salts, and urea. Is this a normal sample? Explain your answer. (2 pts)
Answer:
No, this is not a normal urine sample.
✔ Explanation:
Normal urine contains water, salts, urea, and small amounts of other waste products, but should not contain sugar (glucose) or proteins under healthy conditions.
- Presence of sugar (glucose): Indicates possible diabetes mellitus — when blood glucose levels are too high, the kidneys cannot reabsorb all the glucose, so it appears in urine.
- Presence of proteins (proteinuria): Suggests damage to the glomeruli in the kidneys, allowing proteins like albumin to leak into the filtrate.
➡️ So, the presence of glucose and protein indicates abnormal kidney function or systemic disease (like diabetes or kidney disease).
---
| Question | Answer |
|--------|--------|
| 1 | Feces are not metabolic waste; they are undigested food and waste from digestion, not byproducts of cellular metabolism. |
| 2 | Lungs remove carbon dioxide, a metabolic waste product of respiration. |
| 3a | P: Renal artery<br>Q: Renal vein<br>R: Ureters<br>S: Urinary bladder<br>T: Urethra |
| 3b | X on the kidneys |
| 3c | Controls the release of urine; prevents involuntary leakage. |
| 3d | Blood in P has higher urea/waste content than in Q. |
| 3e | No, because normal urine does not contain sugar or proteins. Their presence suggests health problems like diabetes or kidney damage. |
Let me know if you'd like this formatted as a printable answer sheet!
---
1. Human feces is not an example of excretory waste. Why is this? (1 pt)
Answer:
Feces are not considered excretory waste because they consist mainly of undigested food, bacteria, and dead cells from the digestive tract — not metabolic waste products from cellular processes. Excretory waste refers to substances produced as byproducts of metabolism (like urea, carbon dioxide, and excess ions), which are removed by organs such as the kidneys, lungs, and skin. Feces are a result of digestion and elimination of indigestible material, not metabolic waste.
✔ Key Point: Excretion = removal of metabolic wastes; Egestion = removal of undigested food (feces).
---
2. Why are the lungs considered to be excretory organs? (1 pt)
Answer:
The lungs are considered excretory organs because they remove carbon dioxide (CO₂), a waste product of cellular respiration, from the body. During gas exchange in the alveoli, CO₂ diffuses from the blood into the air sacs and is exhaled. This process helps maintain the pH balance of the blood and eliminates a toxic metabolic byproduct.
✔ Explanation: CO₂ is a metabolic waste generated during aerobic respiration and must be removed to prevent acidosis.
---
3. Study the diagram below and answer the questions that follow.
#### a. Name the parts P, Q, R, S and T. (5 pts)
Based on the standard human urinary system diagram:
- P – Renal artery
*(Carries oxygenated blood to the kidney)*
- Q – Renal vein
*(Carries deoxygenated blood away from the kidney after filtration)*
- R – Ureters
*(Tubes that carry urine from the kidneys to the bladder)*
- S – Urinary bladder
*(Stores urine until it is expelled)*
- T – Urethra
*(Tube through which urine exits the body)*
> ✔ Note: The "sphincter muscle" labeled near T is part of the urethra, controlling the release of urine.
---
#### b. Place an X on the structure that produces urine. (1 pt)
Answer:
Place an X on the kidneys (the two bean-shaped structures at the top of the diagram).
➡️ The kidneys produce urine through the filtration of blood in the nephrons.
---
#### c. Explain the role of the sphincter muscle. (1 pt)
Answer:
The sphincter muscle (specifically the internal and external urethral sphincters) controls the release of urine from the bladder. It contracts to hold urine in the bladder and relaxes to allow urine to pass out through the urethra during urination.
✔ Function: Prevents involuntary leakage of urine and allows voluntary control over urination.
---
#### d. State ONE difference between the composition of blood in P and Q. (1 pt)
Answer:
Blood in P (renal artery) contains higher levels of urea and waste products, while blood in Q (renal vein) has lower levels of urea and waste because the kidneys have filtered them out during urine formation.
Alternatively:
- Blood in P is oxygen-rich, whereas blood in Q is deoxygenated (though oxygen levels are still relatively high due to the kidney’s high metabolic demand).
But the most relevant difference for excretion is:
👉 Urea concentration is higher in P than in Q.
✔ Best Answer: The blood in P has more urea and other metabolic wastes than the blood in Q, because the kidneys filter these substances out.
---
#### e. A sample of urine was collected from the lab. It contained water, sugar, proteins, salts, and urea. Is this a normal sample? Explain your answer. (2 pts)
Answer:
No, this is not a normal urine sample.
✔ Explanation:
Normal urine contains water, salts, urea, and small amounts of other waste products, but should not contain sugar (glucose) or proteins under healthy conditions.
- Presence of sugar (glucose): Indicates possible diabetes mellitus — when blood glucose levels are too high, the kidneys cannot reabsorb all the glucose, so it appears in urine.
- Presence of proteins (proteinuria): Suggests damage to the glomeruli in the kidneys, allowing proteins like albumin to leak into the filtrate.
➡️ So, the presence of glucose and protein indicates abnormal kidney function or systemic disease (like diabetes or kidney disease).
---
✔ Final Summary of Answers:
| Question | Answer |
|--------|--------|
| 1 | Feces are not metabolic waste; they are undigested food and waste from digestion, not byproducts of cellular metabolism. |
| 2 | Lungs remove carbon dioxide, a metabolic waste product of respiration. |
| 3a | P: Renal artery<br>Q: Renal vein<br>R: Ureters<br>S: Urinary bladder<br>T: Urethra |
| 3b | X on the kidneys |
| 3c | Controls the release of urine; prevents involuntary leakage. |
| 3d | Blood in P has higher urea/waste content than in Q. |
| 3e | No, because normal urine does not contain sugar or proteins. Their presence suggests health problems like diabetes or kidney damage. |
Let me know if you'd like this formatted as a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of excretory system worksheet.
