respiratory system chapter 46

name each organ of the mammalian respiratory system and provide its function

nose mouth pharync laryncs surround treacha treachea: rings of cartilage, cilia and mucus, branches into 2 bronchi lunges

gills

organs that exchange oxygen and carbon dioxide with water -Most aquatic animals exchange gases through gills, thin structures that extend from the body surface. Gills can be internal or external.

gas exchange in birds

-(b) First inhalation. As the bird inhales, fresh air (green) ows into the posterior air sacs and partly into the lungs. -c) First exhalation. As the bird exhales, air from the posterior air sacs is forced into the lungs. -d) Second inhalation. Air from the rst breath moves into the anterior air sacs and partly into the lungs (not shown).Air from the second inhalation (gray) ows into the posterior air sacs. -e) Second exhalation. Most of the air from the rst inhalation leaves the body, and air from the second inhalation ows into the lungs.

what is a counter-current exchange system? explain its role in fish gills

-Blood entering the capillaries of the gill lament is de cient in oxygen. The blood ows through the capillaries in a direction opposite to that taken by the water. This countercurrent exchange system ef ciently charges the blood with oxygen. Fish transfer oxygen from the sea water to their blood using a highly efficient mechanism called countercurrent exchange. Countercurrent exchange means the flow of water over the gills is in the opposite direction to the flow of blood through the capillaries in the lamellae.

what is the difference between external gills and internal gills? what are the advantages/disadvantages of each?

-Gills increase the surface area for gas exchange in aquatic animals -obtaining 8-% of oxygen out of the water -high SA, thin flimanets = shorter distance, filament form mesh = increase contact time, counter current echange -steep gradient -external gills: vary widely in appreacnce, unprotected and subject to damage, energy required to move gills, appearance and motion may attract predators -Gills and lungs are the two structures commonly used by animals for respiration. ... The difference between them is that gills involve external extensions from the body surface, whereas lungs possess internal foldings. Gills have evolved independently several times in a variety of animal groups. -Sea stars and sea urchins have dermal gills that project from the body wall. Their ciliated epidermal cells ventilate the gills by beating a stream of water over them. Gases are exchanged between the water and the fluid inside the coelom by diffusion through the gills. Various types of gills are found in some annelids, aquatic mollusks, crustaceans, fishes, and amphibians. Mollusk gills are folded, providing a large surface for respiration. In clams and other bivalve mollusks and in simple chordates, gills may also be adapted for trapping and sorting food. The rhythmic beating of cilia draws water over the gill area, and food is filtered out of the water while gases are exchanged. In mollusks gas exchange also takes place through the mantle. In chordates gills are usually internal. A series of slits per- forates the pharynx, and the gills lie along the edges of these gill slits (see Fig. 32-4). In bony fishes the fragile gills are pro- tected by an external bony plate, the operculum. In some fishes movements of the jaw and operculum help pump water rich in oxygen through the mouth and across the gills. The water leaves through the gill slits.

what is partial pressure explain its role in gas exchange

-The partial pressure is defined as the pressure of a single gas component in a mixture of gases. It corresponds to the total pressure which the single gas component would exert if it alone occupied the whole volume. -The partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood. In contrast, the partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli. -Partial pressure O2 has to be greater in the atmosphere than in the animal in order to diffuse into the animals blood stream. Once in the blood stream the organs it is transfered to must have a lower pressure. Than when CO2 is transfered back the same rules apply.

structure determines function: what features are common in different respiratory organs, and how do these features help with gas exchange?

-moist surfaces in which gases dissolve and diffuse -increased surface area for gas exhnage -extensive blood flow

describe the five factors discussed in class affecting gas exchange. apply these factors to the efficiency of a tracheal system, gills, lungs in mammals, and lungs in birds

1.Medium 2.Surface Area 3.Concentration or Pressure Gradient 4.Distance Gases Travel 5.Contact Time

amphibians use 2 methods for respiration what are they, and explain each. why do amphibians use both methods.

Amphibians have evolved multiple ways of breathing. Young amphibians, like tadpoles, use gills to breathe, and they do not leave the water. As the tadpole grows, the gills disappear and lungs grow (though some amphibians retain gills for life). ... The other means of breathing for amphibians is diffusion across the skin.

buccal pumping

Breathing with the 'cheeks'. Really, they are using the floor of the mouth in a coordinated, rhythmic way to ventilate. Some fishes and all Amphibians use this ventilation method.

evolution of vertebrate lungs

During vertebrate evolution, the surface area of the lung increased. Salamander lungs are simple sacs. Other amphibians and reptiles have lungs with small ridges or folds that increase surface area. Birds have an elaborate system of lungs and air sacs. Mammalian lungs have millions of air sacs (alveoli) that increase the surface available for gas exchange (see Fig. 46-7).

aveoli

It is the tiny sac like structure present in the lungs which the gaseous exchange takes place. -a) A cluster of alveoli. Gas exchange takes place across the thin wall of each alveolus. A network of pulmonary capillaries surrounds each alveolus. Alveolus Red blood cells Capillaries -(b) SEM of alveoli and surrounding pulmonary capillaries. The capillary networks are so dense that each alveolus is surrounded by continuously owing blood.-(c) Color-enhanced TEM of a portion of a capillary and the wall of an alveolus. The dark structure extending through the capillary is part of a red blood cell. Note the very short distance that oxygen must diffuse to get from the air within the alveolus to the red blood cells that transport it to the body tissues.

diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

ram ventilation

Method of forcing water over gills by swimming with mouth open

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

use boyle's law and anatomy of a mammal to explain how inhalation and exhalation occurs

We can breathe air in and out of our lungs because of Boyle's law. According to Boyle's law, if a given amount of gas has a constant temperature, increasing its volume decreases its pressure, and vice-versa. When you inhale, muscles increase the size of your thoracic (chest) cavity and expand your lungs. This increases their volume, so pressure inside the lungs decreases. As a result, outside air rushes into the lungs. That's because a gas always flows from an area of higher to lower pressure. When you exhale, muscles decrease the size of your chest cavity and squeeze your lungs. This decreases their volume, so pressure inside the lungs increases. As a result, air rushes out of the lungs, flowing from an area of higher to lower pressure.

what challenged to gas exchange do aquatic animals face? terrestrial?

aquatic: less avalible oxygen -temperature changes cause oxygen availability fluctuations moving water over respiratory membranes take more effort -water is more dense than air -terrestial aniamsl: deisccation of respiratory membranes

gas echange in insects: tracheal tubes

insects and some other arthropods exchange gases through a system of tracheal tubes, or tracheae. -In contrast to vertebrate gas exchange, blood does not play an essential role in insect gas exchange. -(a) Location of spiracles and tracheal tubes. Air enters the system of tracheal tubes through openings called spiracles. -(b) Structure and function of tracheal tubes. Air passes through a system of branching tracheal tubes that conduct oxygen to all cells of the insect. -(c) SEM of a mole cricket trachea. Rings of chitin reinforce the tubes of the tracheal system, preventing their collapse.

lungs

lungs are adaptations for gas exchange terrestrial habitats

ventilation

movement of air in and out of the lungs