Content Writer
Distal Convoluted Tubule or DCT is a short kidney nephron segment that is situated just after macula densa. This part can be seen interposed between macula densa and collecting duct. It is a short part, though plays an important part in regulating extracellular fluid volume and electrolyte homeostasis. Distal Convoluted Tubule is heterogeneous and can be divided into two parts- DCT1 and DCT2. This division can be done on the basis of their functions and morphological characteristics. Almost 7%- 10% filtered Calcium gets reabsorbed in this part of the human body.
| Table of Content |
Key Terms: Human Physiology, Kidney, DCT, Nephron, excretory system, Proximal Tubule.
What is DCT?
[Click Here for Sample Questions]
Distal Convoluted Tubule (DCT)is basically a part of animal kidney nephron that is situated between the loop of Henle and the collecting tubule. DCT cells have the most Na+/K+-ATPase along the nephron, and it is full of mitochondria.
- DCT is lined by a simple cuboidal epithelium.
- This simple cuboidal epithelium has different characteristic-based cells.
- DCT is situated in Macula densa.
- DCT includes longer cells and cytoplasmic granules.
Distal Convoluted Tubule
Read more:
| Relevant Concepts | ||
|---|---|---|
| Human excretory system | osmoregulation | Modes of excretion |
| Kidney Function Test | Regulation of kidney function | Renal Calculi |
Structure of DCT
[Click Here for Sample Questions]
In the case of vertebrates and some of the invertebrates, the kidney is one of the important parts that controls the water balance and expels metabolic waste. And the functional unit of this body part is known as nephrons. Distal Convoluted Tubule is a small segment of these nephrons.
- DCT is only about 5 mm in length in the case of human anatomy.
- DCT can be divided into two parts- Early Distal Convoluted Tubule or DCT1 and Later Distal Convoluted Tubule or DCT2.
- It has brush border cell linings and it is surrounded by peritubular capillaries.
- The epithelial cells in DCT are cuboidal, with a very little number of microvilli.
- These cells are a little pale.
- DCT2 has a little proportion of intercalated cells.
- As DCT is situated between the loop of Henle and collecting duct, it carries filtrate from the prior to the later.
Structures Of DCT Cells
Importance of DCT
[Click Here for Sample Questions]
Though Distal Convoluted Tubular is a tiny part of the whole kidney anatomy, it has a few very important functions in the animal body-
- DCT, with the help of ADH, helps in water retention in the animal body.
- Another important function of the DCT is controlling the urine retention.
- DCT also plays an important part in regulating extracellular fluid volume and electrolyte homeostasis.
- The sensory epithelium that is involved in tubuloglomerular feedback are called macula densa, which are located in the first segment of the DCT. Within the same nephron, glomerular filtration rate (GFR) and blood flow can be controlled by this tubuloglomerular feedback.
- It helps passing the Na and K ions.
Ion Transfer Through DCT
Things to remember
- Distal Convoluted Tubule (DCT)is basically a part of animal kidney nephron.
- It is situated between the loop of Henle and the collecting tubule.
- DCT is further divided into two parts- Early Distal Convoluted Tubule or DCT1 and Later Distal Convoluted Tubule or DCT2.
- It is about 5mm long.
- This part of the human kidney is very important and it is the main connection between the loop of Henle and the Collecting Tubule.
- It also helps in regulating extracellular fluids in the animal body.
Sample Questions
Ques. What is Distal Convoluted Tubule (DCT)? (1 Mark)
Ans. The Distal Convoluted Tubule (DCT) is an essential part of the animal kidney nephron that is situated between the Henle loop and the collecting tubule. Along the nephron, DCT cells have the most Na+/K+-ATPase and mitochondria.
Ques. What are the importances of DCT in animal physiology? (5 Marks)
Ans. Here are the physiological importances of DCT-
- With the help of ADH, DCT aids in animal body water retention.
- The DCT controls urine retention.
- Electrolyte homeostasis and regulating the volume of extracellular fluid are also important functions of DCT.
- Macula densa, the sensory epithelium responsible for tubuloglomerular feedback, can be found in the first part of DCT . This tubuloglomerular feedback can regulate blood flow and glomerular filtration rate (GFR) within the same nephron.
- It aids in the transfer of Na and K ions.
Ques. Mention some important features of DCT. (5 Marks)
Ans. Here are some of the important features of DCT-
- Distal Convoluted Tubule is a small segment of these nephrons.
- It is only about 5 mm in length in the case of human anatomy.
- It is divided into two parts- Early Distal Convoluted Tubule or DCT1 and Later Distal Convoluted Tubule or DCT2.
- The epithelial cells in DCT are cuboidal, with a very little number of microvilli.
- These cells are a little pale.
- DCT2 has a little proportion of intercalated cells.
Ques. Distal convoluted tubule is lined with simple cuboidal epithelium. Explain. (2 Marks)
Ans. Simple cuboidal epithelium lines distal convoluted tubules. The simple cuboidal epithelium is made of a single layer of cells that look like cubes and serve as protection as well as for the secretion of extracellular fluids. Simple cuboidal epithelium aids in the absorption of sodium ions and water because distal convoluted epithelium is able to control conditional reabsorption.
Ques. What is Nephron? (1 Mark)
Ans. Nephron is the functional unit of the kidney in any animal body. Animal bodies usually have two kidneys. Each of the kidneys is made of a million filtering units. These are called Nephrons.
Ques. What is the difference between proximal tubule and distal tubule? (3 Marks)
Ans. Here are the basic differences between proximal tubule and distal tubule-
| Proximal Tubule | Distal Tubule |
|---|---|
| Proximal Tubule cells in this section have a brush border that allows the absorption of body fluids. | Distal Tubule regulates the urine's concentration and pH in check. |
| PCT receives primary urine from the glomerulus. | The distal convoluted tubule is where wastes like extra salts, ions of K+, Na+, Cl -, and H+ are secreted. |
| The proximal convoluted tubules are the major site of reabsorption for many electrolytes, like- sodium, potassium, chloride, and calcium | This part of the human kidney is very important and it is the main connection between the loop of Henle and the Collecting Tubule. |
Ques. What is the distal convoluted tubule made of? (1 Mark)
Ans. The Distal Convoluted Tubule is a 5mm long part of nephron. It is made of typical absorptive epithelial cells. These cells do not have any brush borders.
Ques. Which epithelium is used in DCT? (1 Mark)
Ans. The distal convoluted tubule (DCT) is made of simple cuboidal epithelium. This part helps with regulating ion concentrations and acid-base balance to maintain homeostasis.
Also Read:
Comments