3) Why pancreas is a mixed gland? How glucose level in the blood is maintained?

1.Pancreas is a glandular organ located in the abdomen.

The pancreas is a mixed gland because it has both endocrine and exocrine functions. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

• As an endocrine gland, it secretes hormones (insulin and glucagon) into the bloodstream to regulate our blood sugar levels. Only one percent of the weight of the pancreas serves as an endocrine gland. The remaining 99 percent of the gland has exocrine functions.

• One the exocrine side the pancreas produces a number of digestive enzymes which empty into the duodenum of the small intestine to chemically digest our ingested foodstuffs.

2.Carbohydrates are broken down into sugars to increase the amount of sugar in the body. When sugar levels are too high, the liver produces and releases insulin which counteracts the sugars.

Blood glucose level is the amount of glucose (sugar) present in the blood of a human or animal. The body naturally tightly regulates blood glucose levels as a part of metabolic homeostasis. The mean normal blood glucose level in humans is about 5.5 mM.

The control of blood sugar levels is determined by the hormones insulin and glucagon, which are secreted into the blood by the pancreas.

When blood sugar levels are too high, the pancreas secretes insulin, which makes cells in the Liver, Muscle, and Fat Tissue take up glucose (sugar) from the blood, and can be converted to glycogen, for storage. Converting glucose to glycogen lowers blood sugar levels, because glycogen does not affect blood sugar levels. Diabetes is when Insulin does not affect cells as much as it should do, and blood sugar stays high.

When the level of blood glucose is low, then glucagon is secreted from the pancreas, and the cells convert glycogen back into glucose.

If there are low amounts of both glucose and glycogen, glucose can be made from other substances in a process called gluconeogenesis.

Basically, insulin lowers your blood sugar level because it pulls the sugar out of the blood stream to provide nutrients to other organs and tissues in the body. It gets more complicated, but this should give you a general idea.

4) Structure of the cell, functions of organelles.

All living organisms on Earth are divided in pieces called cells. The cell is the smallest unit of matter that can carry on all the processes of life.

Cells are grouped as prokaryotic and eukaryotic according to their cellular structure.

Structure of the eukaryotic cell: cell membrane, cytoplasm, organelles.

Cell Membrane is a complex barrier separating the cell from it’s external environment. Cell membrane controls the movement of the particles in and outside the cell.

Cytoplasm is the aqueous environment between the plasma membrane and the nucleus. Transports, absorbs, and processes nutrients. It holds organelles.

The cell organelles in the cytoplasm are:

• Mitochondria- power house of the cell, produces ATP energy.

• Ribosome-synthesize protein.

• Endoplasmic reticulum- material production and transport.

• Golgi complex- formation, packing and secretion of exportiable materials.

• Lysosome- contains digestive enzymes responsible for cellular digestion.

• Peroxisomes -destroys toxic chemicals such as hydrogen peroxide.

• Vacuoles- store materials, waste and water.

• Plastids- variety of functions.

• Centrioles- Involved in the cell division. Forms spindle fibers.

• Nucleus- the control center of the cell.

• Rough Endoplasmic Reticulum (RER)- Makes/Transports Proteins.

• Smooth Endoplasmic Reticulum (SER)- Makes/Transports Fats.

• Cell Wall- Surrounds/protects a plant cell and gives the cell it's boxy shape, prevents bursting in most environments.

• Flagella/Cillia-Flagella-cellular locomotion, Cillia- provides cellular movement.