IB Biology Topic 6, IB Biology Topic 6

• Topic 6.1Absorption


  the movement of a substance, such as a liquid or solute, across a cell membrane by means of diffusion, osmosis, or active transport.
• Topic 6.1Amylase


  an enzyme, found mainly in saliva and pancreatic fluid, that converts starch and glycogen into simple sugars.
• Topic 6.1Cellulose


  a complex carbohydrate that is composed of glucose units, and forms the main constituent of the cell wall in most plants.
• Topic 6.1Circular muscles


  the inner layer of smooth (involuntary) muscle of the muscle coat (muscularis externa) of the small intestine in which the muscle fibres encircle the lumen.
• Topic 6.1Dialysis


  the separation of smaller molecules from larger molecules, or of dissolved substances in a solution by selective diffusion through a semi-permeable membrane.
• Topic 6.1Endopeptidase


  any of a large group of enzymes that catalyse the hydrolysis of peptide bonds in the interior of a polypeptide chain or protein molecule.
• Topic 6.1Enzymes


  proteins or conjugated proteins produced by living organisms and functioning as biochemical catalysts.
• Topic 6.1Epithelium


  the thin tissue forming the outer layer of a body's surface and lining the alimentary canal and other hollow structures.
• Topic 6.1Glycogen


  a polysaccharide that is the main form of carbohydrate storage in animals and occurs primarily in the liver and muscle tissue. It is readily converted to glucose when needed by the body to satisfy its energy needs.
• Topic 6.1Lipase


  a pancreatic enzyme that catalyses the breakdown of lipids through the hydrolysis of the linkages between fatty acids and glycerol in triglycerides and phospholipids.
• Topic 6.1Liver


  a large glandular organ located in the upper right side of the abdominal cavity active in the secretion of bile and various metabolic processes.
• Topic 6.1Longitudinal muscles (of the stomach)


  the outer longitudinal layer of smooth muscles, continuous with that of the esophagus.
• Topic 6.1Lumen


  the inner open space or cavity of the small intestine.
• Topic 6.1Macromolecule


  a very large molecule, such as a polymer or protein, consisting of many smaller structural units linked together.
• Topic 6.1Mineral ions


  individual elements with an electrical charge.
• Topic 6.1Monomer


  a molecule that can combine with others to form a polymer.
• Topic 6.1Mucosa


  a mucus-secreting membrane lining all bodily passages that are open to the air, such as the digestive tract.
• Topic 6.1Nucleic acids


  complex compounds found in all living cells composed of bases, carbohydrates, and phosphoric acid. Nucleic acids in the form of DNA and RNA control cellular function and heredity.
• Topic 6.1Pancreas


  a gland in vertebrates, lying behind the stomach, that secretes pancreatic juice into the duodenum and insulin and glucagon into the bloodstream.
• Topic 6.1Small intestine


  the narrow, winding, upper part of the intestine where digestion is completed and nutrients are absorbed by the blood.
• Topic 6.1Starch


  a polysaccharide composed of glucose units that occurs widely in plant tissues in the form of storage
• Topic 6.1Villus (plural villi)


  one of the minute finger-shaped processes of the mucous membrane of the small intestine that serve in the absorption of nutrients.
• Topic 6.1Vitamin


  any of various fat-soluble or water-soluble organic substances essential in minute amounts for normal growth and activity of the body and obtained naturally from plant and animal foods.
• Topic 6.2Aorta


  the main artery of circulatory system that carries blood from the lef side of the heart to the arteries of all limbs and organs except the lungs.
• Topic 6.2Arteriole


  a small terminal branch of an artery that connects with a capillary.
• Topic 6.2Artery


  a vessel that carries blood away from the heart to organs through the body
• Topic 6.2Atrium (plural atria)


  a chamber that receives blood returning to the heart.
• Topic 6.2Blood pressure


  the hydrostatic force that blood exerts against the wall of a blood vessel
• Topic 6.2Capillary


  a microscopic blood vessel that penetrates the tissues and consists of a single layer of endothelial cells to allow exchange with interstitial fluid.
• Topic 6.2Cardiac output


  the volume of blood pumped per minute by the left ventricle of the heart.
• Topic 6.2Diastolic pressure


  the minimum blood pressure during relaxation of heart muscles.
• Topic 6.2Elastic fibres


  a thick, yellow connective-tissue fibre composed principally of elastin and characterized by giving great elasticity to tissues in the body.
• Topic 6.2Epinephrine


  a hormone produced as a response to stress, also called adrenaline.
• Topic 6.2Medulla


  the lowest part of the brain that controls autonomic and homeostatic functions.
• Topic 6.2Myogenic contraction


  A contraction of the heart without external stimulation from a nerve.
• Topic 6.2Pacemaker


  a specialized region of the right atrium that sets the rate of heart contraction, also called the sinoatrial (SA) node.
• Topic 6.2Pulmonary circulation


  the separated circulatory system that links the lungs and heart in humans.
• Topic 6.2Pulse


  the force of blood leaving the heart in one heartbeat; it is felt where arteries pass near the skin.
• Topic 6.2Systemic circulation


  the separated circulatory system that links the heart to the rest of the body.
• Topic 6.2Systolic pressure


  The maximum blood pressure caused by heart muscles contracting and pumping blood.