Glucose molecules are transported across cell membranes by facilitated diffusion or active transport. Most of the time, the former process takes place, as it requires no energy from the cell. Active transport indirectly requires energy from the hydrolysis of ATP.Continue Reading
When glucose molecules move into the cell by facilitated diffusion, the concentration gradient plays an essential part. Glucose only enters the cell by diffusion if its intracellular concentration is lower than the extracellular one. To move across the cell membrane without requiring any energy, glucose needs a protein that acts like a carrier. Because there is a limited number of transporting proteins, this process reaches a maximum rate of transport that cannot be improved, even if the concentrations on either side of the membrane continue to present a significant difference.
Glucose enters the cell against the concentration gradient, by active transport. In fact, glucose takes part in a process of cotransport, along with an ion such as Na+. When the sodium ion binds to the receptor, the binding of glucose is also stimulated, despite its concentration gradient. The receptor closes on the exterior side and opens on the inside of the cell, releasing the sodium ion along with the glucose molecule. The passive and active glucose transport systems work independently, and drugs that inhibit one of the processes do not influence the other.Learn more about Human Anatomy
Vascular connective tissue is the tissue responsible for transport in the body of an animal. There are several types of connective tissue, such as adipose tissue, the lymphatic system, osseous tissue and bone marrow. Cartilage is a type of connective tissue that is non-vascular, because it doesn't transport anything.Full Answer >
Ultrafiltration is how urea, salt, water and glucose are taken out of the blood in the kidneys. The things that are filtered out need to be returned to the blood through a process called selective reabsorption.Full Answer >
Insulin is a hormone that lowers the amount of glucose, or sugar, in the blood. A low level of insulin always exists in the bloodstream, but the pancreas secretes more after a meal is eaten. Insulin is made and secreted in the islet beta cells of the pancreas.Full Answer >
According to WebMD, high blood sugar levels cause excess glucose in the urine. High blood sugar levels are common in people with uncontrolled diabetes. When an individual's blood sugar level is high, it can spill into the urine. Glucose in the urine can also occur if the kidneys are suffering from damage or disease.Full Answer >