In this section, you will read about excretion in human beings. In addition, you will also get to solve various important MCQs on human excretory system.
Excretion in Animals | Human Excretory System
Excretion refers to sum total of all the processes of removing the waste products of cellular metabolism and extra water from the body.
The excretory system in humans consists of a pair of kidneys, a pair of ureters, a urinary bladder and a urethra. In addition, organs like liver, large intestine, lungs also act as excretory organs.
During excretion, Nitrogenous wastes such as urea and uric acid , and water are removed.
Nephron is the basic filtration unit. Main components of the nephron are :glomerulus, Bowman’s capsule, renal tube.
Kidneys
Kidneys are present on either side of the backbone in the abdomen.
Kidneys produce urine and urine from kidney passes through the ureters into the urinary bladder
Each Kidney is divided into three distinct regions:
(a) Outermost cortex: consists of nephrons
(b) Middle Medulla region: consists of tubules
(c) Inner Pelvis region: where urine is drained from all the collecting tubules.
The functional unit of kidney is NEPHRON.
Each kidney consists of millions of nephrons and each nephron consists of the following parts:
(a) Bowman’s capsule: It is a cup shaped structure and receives the blood vessels.
(b) Proximal Convoluted Tubule: Water and reusable materials from the blood are now reabsorbed back into it.
(c) The loop of Henle: It is in this area in which urine becomes concentrated as water is reabsorbed.
(d) Distal Convoluted Tubule: It is where the kidney hormones cause their effect.
(e) Collecting Duct: The collecting ducts together form the renal pelvis.
Lungs
Water vapours and carbon dioxide are excreted from the human body through lungs.
Lungs are the primary respiratory organs.
Skin
The skin is the largest organ in the body.
Sweat glands filter water, urea and salts from the blood. Although the main role of sweat production is to cool the body and maintain temperature homeostasis, sweating also eliminates excess water and salts, as well as a small amount of urea
Skin protects the different organs of the body.
Liver
Liver removes worn out cells and excess of amino acids from the blood. liver converts ammonia( a toxic by-product of protein catabolism) into urea, which is then filtered from the blood by the kidneys and excreted in urine.
It is the first line of defence when it comes to hormones, fats, alcohol, and drugs.
Large Intestine
The main function of large intestine as an excretory organ, is to eliminate solid wastes that remain after the digestion of food and the extraction of water from indigestible matter in food waste.
Disorders Related To Excretion
The disorders related to excretion in animals are discussed below:
| Disease | Condition |
| Anuria | When no urine is passed |
| Dysuria | Painful Urination |
| Polyuria | Excessive Urination |
| Nocturia | Urination during night |
| Uremia | Increased level of urea in blood |
| Diabetes Insipidus | Excessive urination due to defeciency of Antidiuretic hormone, mainly in alcoholics. |
| Urethritis | Inflammation of Urethra |
| Renal failure | Failure of kidneys |
| Renal Calculi | Stones in kidneys |
MCQs On Human Excretory System
This set contains many important MCQs on human excretory system. Solve these MCQs on to check and enhance your level of preparation for competitive exams.
What is the basic functional unit of Kidney?
- Nephron
- Glomerulus
- Loop of Henli
- Neuron
Nephron
The largest excretory organ is:
- Lungs
- Skin
- Large intestine
- Kidney
Skin
Urea is produced as an excretory substance in human body in:
- Urinary Bladder
- Liver
- Kidney
- Large intestine
Liver
Bowman’s Capsule is also known as:
- Adrenal Capsule
- Renal Capsule
- Hepatic Capsule
- Gastric Capsule
Renal Capsule
The disorder in which large amounts of urine are produced is known as:
- Diabetes Millitus
- Dysuria
- Mycturia
- Diabetes Insipidus
Diabetes Insipidus
Females are more prone to Urinary Tract Infection because;
- They have longer urethra than men.
- They have shorter urethra than men.
- Their urinary bladder is rigid and small.
- Their ureters are shorter than men.
They have a shorter urethra than men
The disorder in which urea accumulation is comparatively higher is known as:
- Nephritis
- Renal Calculi
- Uremia
- Dysuria
Uremia
The ph of human urine is normally:
- 3 to 5
- 4.6 to 8.0
- 7.2 to 10.4
- 7
4.6 to 8.0
The condition characterized by no passage of urine is known as:
- Dysuria
- Polyuria
- Nocturia
- Anuria
Anuria
The main function of the large intestine is:
- Concentrating bile juice
- Absorbing nutrients from chyme
- making hormones that regulate blood sugar
- compacting and eliminating waste materials
compacting and eliminating waste materials
The sweat glands release waste products like:
- Water and bile
- Water and salts
- salts and bile
- Salts and bilirubin
Water and Salts
These were some important MCQs on human excretory system. We are sure that you will find these MCQs on human excretory system very useful and hope that you will share them with your friends.