Related Concept Videos

Glucose Homeostasis: Pancreatic Islets and Insulin Secretion01:27

Glucose Homeostasis: Pancreatic Islets and Insulin Secretion

The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are...
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Alveoli and Alveolar Ducts01:26

Alveoli and Alveolar Ducts

The respiratory zone of the human body, which stands in contrast to the conducting zone, comprises the structures that actively participate in the exchange of gases. The initiation of this zone is marked by the terminal bronchioles converging into respiratory bronchioles, the tiniest bronchiole classification. The respiratory bronchioles give way to the alveolar ducts that opens into a congregation of alveoli. Actively involved in gas exchange, alveoli resemble tiny sacs similar to clusters of...
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Renal Tubule and Collecting Duct01:24

Renal Tubule and Collecting Duct

The renal tubule is divided into three parts: the proximal convoluted tubule (PCT), the Loop of Henle (LOH), and the distal convoluted tubule (DCT).
Proximal Convoluted Tubule (PCT):
The PCT is the initial segment of the renal tubule, extending from the Bowman's capsule that encloses the glomerulus. Its convoluted structure and microvilli-lined cells increase the surface area for reabsorption. The PCT reabsorbs glucose, amino acids, sodium, and water from the filtrate, ensuring essential...
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Accessory Ducts of the Male Reproductive System01:25

Accessory Ducts of the Male Reproductive System

The male reproductive system is a complex network of organs and tissues that work together to produce and transport sperm. The epididymis, vasa deferens, ejaculatory ducts, and urethra are the accessory ducts involved in sperm maturation and transportation. These ducts play a critical role in the production and transportation of sperm from the testes to the urethra, where it is then released during ejaculation.
The epididymis is a small, comma-shaped organ located at the back of each testicle....
3.2K
Reabsorption and Secretion in the DCT and Collecting Duct01:26

Reabsorption and Secretion in the DCT and Collecting Duct

The early phase of the DCT manages the reabsorption of approximately 10-15% of filtered water, 5–10% of filtered sodium, and 5–10% of filtered chloride. This process is facilitated by Na+–Cl− symporters in apical membranes and sodium-potassium pumps, as well as Cl− leakage channels in basolateral membranes. The early DCT also stands out as a site where parathyroid hormone (PTH) stimulates calcium reabsorption, depending on the body's requirements.
The distal...
3.4K
Pancreatic Juice and Secretion01:26

Pancreatic Juice and Secretion

Pancreatic juice is a clear fluid produced by the pancreas, containing water, salts, sodium bicarbonate, and enzymes vital for digestion in the small intestine. It helps break down large molecules, facilitating nutrient absorption.
When acidic chyme from the stomach enters the duodenum, it triggers the release of secretin, a hormone that prompts pancreatic juice secretion. After a fatty meal, cholecystokinin, another hormone, stimulates gallbladder contraction and enhances enzyme-rich...
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