Topic 3

• Surface area to volume ratio is calculated by dividing the surface area of an organism by its volume.
• The larger an organism is, the smaller its surface area to volume ratio.
• Small organisms like single-celled organisms like amoeba have very large surface areas compared to their volume, allowing them to diffuse gases across their surface without additional special adaptations.
• Larger organisms, due to their smaller surface area compared to their volume, cannot rely on simple diffusion to distribute gases evenly throughout the organism.
• Larger organisms typically have higher metabolic needs, which means the chemical reactions within a cell are happening faster, requiring additional adaptations for mass transport or transport across cells.
• Micelles increase the surface area available for the lipase to bind onto and therefore act on, making digestion more efficient.
• Physical digestion involves emulsification and micelle formation.
• Chemical digestion is the action of the lipase.
• A micelle is a vesicle formed of fatty acids, glycerol monoglycerides, and bile salts, aiding in the absorption of lipids.
• Lipids are digested into monoglycerides and fatty acids by the action of lipase, creating these tiny structures which are then modified back into triglycerides inside of the endoplasmic reticulum and the golgi body.
• Absorption in mammals takes place in the ilium, linking to the villi and the microvilli, with adaptations like the thin walls, the large surface area, and the concentration gradients maintaining the process.
• Hemoglobin is involved in the mass transport of oxygen around the body, demonstrating a quaternary structure protein made up of four polypeptide chains.
• Myoglobin, found in the muscle tissue of vertebrates and fetuses, is a type of hemoglobin.
• The oxyhemoglobin dissociation curve is a way to look at how hemoglobin behaves in different conditions, demonstrating cooperative binding and the bohr effects.
• Pulmonary ventilation is the total volume of air moved into the lungs during one minute, measured in decimeters cubed for volume and per minute.
• The calculation for pulmonary ventilation is the tidal volume times the ventilation rate.
• Tidal volume is the volume of air total volume of air breathed in during one breath.
• Ventilation rate is how many times you breathe per minute.
• Gas exchange occurs between the epithelium and the blood in the alveoli, which are tiny air sacs located in the lungs.
• Alveoli epithelium cells are very thin to minimize the diffusion distance.
• Alveoli are surrounded by a network of capillaries to maintain the concentration gradients.
• Terrestrial insects have a large surface area to volume ratio due to their small size, but their exoskeleton prevents gas exchange.
• Insects have a tracheal system where ventilation and gas exchange occur, which includes a trachea, sphericals, and tracheals.
• Sphericals are the tiny holes that run along the abdomen of insects, where oxygen and carbon dioxide enter and leave.
• Trachea are tubes that branch into smaller tubes, known as tracheals, which extend throughout all of the tissue in the insects to deliver oxygen to all of the respiring cells.
• Gases can move into the tracheal system by diffusion, mass transport, or when the insects are in flight.
• The semilunar valves open above the atria and pulmonary artery, causing blood to be pumped out of those two blood vessels.
• Cardiac output is the volume of blood which leaves one ventricle in one minute, and can be calculated by doing the heart rate times the stroke volume.
• Tissue fluid is a fluid that contains water, glucose, amino acids, fatty acids, ions, and oxygen, and is the liquid that is forced out of the capillaries to bathe the cells.
• Ultra filtration is the process where small molecules are forced out of the capillary to the surrounding cells, while larger molecules like red blood cells, platelets, and large proteins remain in the blood.
• The hydrostatic pressure within the capillary decreases as the liquid is forced out, causing the water potential of the blood in the capillary to drop compared to the water potential in the liquid surrounding the cells, resulting in re-entry of liquid by osmosis.
• Mass transport in plants involves the mass transport of water, starting with transpiration, the loss of water vapor from the stomata on the leaves.
• Light intensity, temperature, humidity, and wind are key factors that affect the rate of transpiration.
• The major blood vessels are connected within the double circulatory system via arteries, arterioles, capillaries, and veins.
• The walls of the heart have a very thick muscular layer so it can contract with high force to deliver high pressure blood to all of the body cells.
• The cardiac muscle is myogenic, meaning it can contract and relax without nervous or hormonal stimulation.
• The cardiac muscle never fatigues as long as it has a constant supply of oxygen and glucose.
• The coronary arteries supply the cardiac muscle with oxygen and glucose, branching off from the aorta.
• A blockage in one of the coronary arteries can cause a myocardial infarction or heart attack.
• The heart has four chambers: two atria at the top and two ventricles at the bottom.