Gills are adapted for gas exchange in aquatic environments. In a fish, gas exchange is enhanced by ventilation of the gills (moving water past the gills), and countercurrent flow of water and blood. Cold water holds more oxygen than warm water. Fresh water holds more oxygen than salt water. And turbulent water holds more oxygen than still water. Therefore, fish go to whichever that is the easiest for them to breath in the oxygen.
WHAT ARE TETRAPODS?
Tetrapods seem to have evolved in shallow water. This is because fossil fish with legs had lungs and gills. Legs may have helped them lift up to gulp air. The fossil fish illustrates these air-breathing adaptations. The first tetrapods on land diverged into three major lineages. Amphibians use small lungs and their body surfaces. Nonbird reptiles have lower metabolic rates and simpler lungs. Birds and mammals have higher metabolic rates and more complex lungs.
WHAT IS ALVEOLI?
Alveoli are well adapted for gas exchange. High surface area of capillaries and high surface are of alveoli. In alveoli, oxygen diffuses into the blood, and carbon dioxide diffuses out of the blood. Basically, It is the place in the body where carbon dioxide and oxygen change places in the lungs. It is the place in the body where carbon dioxide and oxygen changes in the lungs.
SUMMARY:
The process of gas exchange is the interchange of oxygen and carbon dioxide between an organism and its environment. Three phases of gas exchange are breathing, transporting of oxygen and carbon dioxide in blood, and body tissues take up oxygen and release carbon dioxide. Cellular respiration requires a continuous supply of oxygen and the disposal of carbon dioxide. Respiratory surfaces must be thing and moist for diffusion of O2 and CO2. Compared to water, using air to breathe has two big advantages; air contains higher concentrations of O2. And air is lighter and easier to move. For humans to breathe, from the nasal cavity air next passes to the pharynx, past the vocal cords, into the trachea, into the paired bronchi, into bronchioles, and finally to the avaoli. Smoking is very bad for lungs and the respiratory system. It can cause lung cancer, heart disease, and emphysema. Breathing is the alternate inhalation and exhalation of air. Inhalation occurs when the rib cage expands, or when the diaphragm moves downward. Exhalation occurs when the rib cage contracts, or when the diaphragm moves upward. Not all air is expelled during exhalation. One-way flow of air in birds reduces dead air and increases their ability to obtain oxygen. Breathing is usually under automatic control. The heart pumps blood to two regions, the right side pumps oxygen poor blood to the lungs, and the left side pumps oxygen rich blood to the body. In the lungs, blood picks up O2 and drops off CO2. In the body tissues, blood drops off O2 and picks up CO2. Most CO2 in the blood is transported as bicarbonate ions in the plasma. In the placenta, capillaries of maternal blood and fetal blood run next to each other. Fetal hemoglobin attracts O2 more strongly than adult hemoglobin. Thus, fetal blood takes oxygen from maternal blood. At birth, CO2 in fetal blood increases. Breathing control centers initiate breathing.
KEY TERMS:
- Gills: specialized body parts that promote gas exchange in fish and amphibians
- Tracheal systems: specialized body parts that promote gas exchange in arthropods
- Lungs: in tetrapods that live on land such as amphibians, reptiles, birds, and mammals
- Trachea: held open by cartilage rings
- Alveoli: grapelike clusters of air sacs, where gas exchange occurs
- Mucus: protection of lungs, which can be damaged by smoking
- Breathing control centers: in the brain sense and respond to CO2 levels in the blood
- Hemoglobin: transports oxygen, buffers blood, and transports CO2
- Human fetus: instead of breathing with lungs, exchanges gases with maternal blood in the placenta
- Placenta: an organ attached to the lining of your womb during pregnancy
This diagram shows where the blood from comes from, and goes to. Right Heart receives blood from the body and pumps it through artery to the lungs where it picks up oxygen. •Left Heart receives oxygen-rich blood from the lungs and pumps it through the aorta to the body.
This video talks briefly about the respiratory system.
5 Facts:
1) Animals exchange O2 and CO2 across moist body surfaces.
2) In the human respiratory system, branching tubes convey air to lungs located in the chest cavity.
3) Without healthy cilia, smokers must cough to clear dirty mucus from the trachea.
4) Negative pressure breathing ventilates our lungs.
5) A drop in blood pH increases the rate and depth of breathing.
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