Gas exchanges in different mediums

Aquatic Gas Exchange is about water. If there is water in the medium.
Advantage of aquatic gas exchange:
Keeping surface moist is no problem
Disadvantage of aquatic gas exchange:
O2 concentrations in water are low, especially in warmer and saltier environments


Terrestrial Gas Exchange mean , gas exchange is occuring on dry lands.
Advantages:
O2 diffuses faster in air
Air contains much more O2 than water
Disadvantage:
Surfaces must be internal to avoid loss of water due to evaporation

mechanishm of breating espiration

Respiratory system is consists of taking breathing oxygen from the air and give off carbon dioxide that is produced in cells.

They have three phases:
1. Exchange in the lungs.
2. The transport of gases.
3. Respiration in cells and tissues.

The air enters the lungs and out of them by breathing movements :
Inspiration in the air enters the lungs because they swell to increase the volume of the rib cage. This is because the diaphragm descends and the ribs are lifted.
Espiration in the air is thrown to the outside because the lungs are compressed to reduce the size of the rib cage, as the diaphragm and ribs return to their normal position.
Really great mechanism for respiratory system. Its amazing..

respiratory system

The breath serves two successive stages, carried out to the muscular action of the diaphragm and the intercostal muscles, it is controlled by the respiratory center of the medulla oblongata. In inspiration, the diaphragm is contracted and the intercostal muscles rise and widen the ribs.

The rib cage volume gains and penetrates outside air to fill this space. During the exhalation, the diaphragm relaxes and the ribs down and move inland. The rib cage diminishes their ability and lungs leak air outwards. Body needs oxygen and removes carbon dioxide or carbon dioxide gas.

bronchioles alveoli air sacs

As you know breathing is an involuntary and automatic process, controlled by pns. It extracts oxygen from the air inspired and expel waste gases with the breath.

The air is inhaled through the nose then it heated and moistened and moves on to the pharynx, larynx and continues to penetrate into the trachea. In the middle of the chest, the trachea is divided into two bronchi which are divided again, again and again, bronchus in secondary, tertiary, and, finally, some 250,000 bronchioles.

At the end of the bronchioles are grouped in clusters of alveoli, small air sacs, where the exchange of gases in the blood. The lungs contain about 300 million alveoli, which deployed occupy an area of 70 square meters, about 40 times the size of the skin

respiration

The lungs, the spongy bodies, large and conical, play a vital role since they are responsible for the oxygen in the body. Oxygen combustion uses the human body, ie it allows fuel to burn the nutrients in food. The body produces and the energy needed to fill its needs.

The right lung has three lobes, while the left has only two, but has a location for the heart. The lungs may contain adult three liters of air around. These are the chest muscles that are responsible for the work of breathing as the lungs have no muscles themselves. Much of this work is done by a muscle end at the base of the lungs, the diaphragm. The involuntary and uncontrolled contraction of the muscle because the "hiccups". Breathing is an automatic phenomenon, present even when one is unconscious. At rest, the respiratory rate of the average adult is 16 breaths per minute.

The air that inspires it descends into the trachea to the bronchi, which separate

to enter the left or right lung. Bronchial themselves branch into several bronchioles, which are divided into half a dozen cellular channels, which are narrow conduits in the opening air sacs. This branched structure uniting the trachea and bronchi, the bronchioles, canals and alveolar air sacs is often called "bronchial tree" because of its resemblance to the branches and leaves of a tree. A dozen cells are clustered together on each bag honeycomb. This is in the thousands of tiny air sacs in the lungs, the oxygen provided by the inspiration through the membrane of the alveolar wall to be transferred to red blood cells in capillaries (small blood vessels on alveoli). Conversely, waste gases pass blood red air cells to be eliminated by the end. The cells are particularly susceptible to infection because they are a hot and humid environment conducive to the proliferation of viruses and bacteria. This explains why a simple cooling can develop into pneumonia or pneumonia *, which are characterized by infection and inflammation sometimes serious, can compromise the ventilation of the lungs. However, the body needs a constant supply of oxygen and nutrients costs to remain alive.

human respiration

Human beings can survive several weeks without eating and without drinking a few days, but he must breathe at all times to live. Like drinking and eating, the respirationest essential to cellulesdu body. Without oxygènerendu available through respiration and blood circulation, the cells could no longer fulfill their functions and ensure the survival of the entire body.

In this dish, we will explore the different organs of the respiratory system.

amazing facts about respiratory system circulatory system

There are some amazing and interesting facts about human circulatory system.

* The right lung is slightly larger than the left.
*At rest, the body takes in and breathes out about 10 liters of air each minute.
* The surface area of the lungs is roughly the same size as a tennis court.
* The highest recorded "sneeze speed" is 165 km per hour.
* The capillaries in the lungs would extend 1,600 kilometers if placed end to end.
* Half a liter of water a day through breathing. Water vapor when we breathe onto glass
* A person at rest usually breathes between 12 and 15 times a minute.
* The breathing rate is faster in children and women than in men.

what is respiratory system

Respiratory system is the system that helps you breath in and out, so oxygen (02) can be pumped through your body and carbon dioxide (CO2) can be removed from the blood stream, remember that the Respiratory system is made up of many different organs.

Respiratory System in Mammals

The mammalian heart is more compartmentalized than reptile lungs.
Bronchi, bronchioles, alveoli.
In each lung of a human, there are about 150.000.000 alveoli.
The alveoli for gas exchangePharinx, Trachea, larynx
Endothelial cell layer in respiratory passageway.
Mucus covering the respiratory cell surface.
Ciliated cells
Nose, nasal cavity and its function for humidification of airUpper tract
Nose, pharynx and associated structures
Lower tract
Larynx, trachea, bronchi, lungs

Alveolar Lining Regeneration

Daily turnover of about 1G/o of the type II cells, whose mitotic progeny form both type I and type 11 cells, allows for normal alveolar lining renewal. When these lining cells are destroyed by inhalation of toxic gases, replacements for both types of cells are similarly derived from the surviving type II cells. Respiratory system

Pulmonary Surfactant

Respiratory system :
It is continuously synthesized and secreted by type II alveolar cells onto the alveolar surfaces, pulmonary surfactant is removed from these surfaces by alveolar macrophages and by type I and II alveolar cells. Its composition and continuous turnover allow it to serve 2 major functions. Not only does it reduce surface tension in the alveoli, but also it is thought to have some bactericidal effects, cleaning the alveolar surface and preventing bacterial invasion of the many capillaries in the septa.

The surfactant forms a thin 2-layer film over the entire alveolar surface. The film consists of an aqueous basal layer (bypopbase) composed mainly of protein, which is covered by a monomolecular film of phospholipid (mainly di palmitoyl lecithin) whose fatty acid tails extend into the lumen. By reducing surface tension, the surfactant helps prevent collapse of the alveoli during expiration. It thus eases breathing by decreasing the force required to reopen the alveoli during the next inspiration.

Because surfac tant secretion begins in the last weeks of fetal development, premature infants often suffer a condition called hyaline membrane disease, evidenced by respiratory distress (labored Ibreathing) caused by the lack of surfactant. Surfactant secretion can be induced by administering glucocorticoids, significantly improving the infant's condition and chances for survival.

Pulmonary Surfactant:

Continuously synthesized and secreted by type II alveolar cells onto the alveolar surfaces, pulmonary surfactant is removed from these surfaces by alveolar macrophages and by type I and II alveolar cells. Its composition and continuous turnover allow it to serve 2 major functions. Not only does it reduce surface tension in the alveoli, but also it is thought to have some bactericidal effects, cleaning the alveolar surface and preventing bacterial invasion of the many capillaries in the septa. in Respiratory system the surfactant forms a thin 2-layer film over the entire alveolar surface. The film consists of an aqueous basal layer (bypopbase) composed mainly of protein, which is covered by a monomolecular film of phospholipid (mainly di palmitoyl lecithin) whose fatty acid tails extend into the lumen. By reducing surface tension, the surfactant helps prevent collapse of the alveoli during expiration. It thus eases breathing by decreasing the force required to reopen the alveoli during the next inspiration. Because surfac tant secretion begins in the last weeks of fetal development, premature infants often suffer a condition called hyaline membrane disease, evidenced by respiratory distress (labored Ibreathing) caused by the lack of surfactant. Surfactant secretion can be induced by administering glucocorticoids, significantly improving the infant's condition and chances for survival.

RESPONSE OF NERVE TISSUE TO INJURY

ØA. Damage to the Cell Body: Because mature neurons cannot divide, dead neurons cannot be replaced. Neurons not connected with otherfunctioning neurons or end organs are useless, and mechanisms have evolved to dispose of them. Thus, if a neuron makes synaptic contact with Only one other neuron and the latter is destroyed, the former undergoes autolysis, a process termed transneuronal degeneration. Most neurons, however, have multiple connections.

ØB. Damage to the Axon: Regeneration can occur in axons injured or severed Far enough from the soma to spare the cell. Such injuries are followed by partial degeneration and then regeneration. Nerve system

1. Degeneration. A crushed or severed axon degenerates both distal and proximal to the injury. Distal to the site Of injury, both the axon and myelin sheath undergo complete degeneration connection with the soma has been lost. During this Wallerian, descendent, or secondary degeneration, whichusually lakes about 2-3 days, nearby Schwann cells proliferate, phagocytose degenerated tissue, and invade the remaining endoneurial channel. Proximal to the site of injury, degeneration of the axon and myelin sheath is similar but incomplete. This retrograde, ascendent, orprimary degeneration proceeds for about 2 internodes before the injured axon is sealed. The cell body also changes in response to injury. The perikaryon enlarges; chromatolysis, or dispersion of Nissl substance, occurs; and the nucleus moves to an eccentric position. Proximal degeneration and cell body changes fake about 2 weeks.

2. Regeneration. This begins in the third week after the injury. As the perikaryon gears up for increased protein synthesis, the Nissl bodies 'eappear. The axon's proximal stump gives off a profusion of smaller processes called neurites; one of these encounters and grows into the endoneurial channel, while the others degenerate. In the channel, the neurite grows 3-4 mm/d, guided and then myelinated by the Schwann cells. Growth is maintained by orthograde axoplasmic transport of material synthesized in the soma. When the tip of the neurite reaches its termination, it connects with its end organ or another neuron in the chain. If the cut ends of a severed nerve are matched by by fascicle size and arrangement and sutured together by their epineurial sheaths within 34 weeks after injury, sensory and motor innervation can often be restored. If the gap between the cut ends is too wide, the neurites may fail to find endoneurial sheaths to grow into and may grow out in a potentially painful disorganized swelling called a neuroma. Target organs deprived of innervation often atrophy.

Alveolar Cell Types:

1. Type I cells. Also called type I alveolar cells, type I pneumocytes, and squamous alveolar cells, these are squamous epithelial cells that make up 97% of the alveolar surfaces.

They are specialized to serve as very thin (often only 25 nm in width) gas-permeable components of the blood-air barrier. Their organelles leg, Golgi complex, endoplasmic reticulum, mitochondria) cluster around the nucleus.

Much of the cytoplasm is thus unobstructed by organelles, except for the abundant small pinocytotic vesicles that are involved in the turn over of pulmonary surfactant and the removal of small particles from the alveolar surfaces. They attach to neighboring epithelial cells by desmosomes and occluding junctions.

The latter reduce pleural effusion--leakage of tissue fluid into the alveolar lumen. Type I cells can be distinguished from the nearby capillary endothelial cells by their position bordering the alveolar lumen and by their slightly more rounded nuclei.

2. Type II cells. These cells, which are also called type II alveolar cells, type II pneumocytes, great alveolar cells, and alveolar septal cells, cover the remaining 3% of the alveolar surface. They are interspersed among the type I cells, to which they attach by desmosomes and occluding junctions.

Type II cells are roughly cuboidal with round nuclei; they occur most often in small groups at the angles where alveolar septal walls converge. At the electron microscope level, they contain many mitochondria and a well-developed Golgi complex, but they are mainly characterized by the presence of large (0.2-um), membrane-limited lamellar (mutlilamellar) bodies. These structures, which exhibit many closely apposed concentric or parallel membranes (lamellae), contain phospholipids, glycosaminoglycans, and proteins.

Type II cells are secretory cells. Their secretory product, pulmonary surfactant, is assembled and stored in the lamellar bodies, which also carry it to the apical cytoplasm. There, the bodies fuse with the apical plasma membrane and release surfactant onto the alveolar surface. 3. Alveolar marcrophages. Known also as dust cells, these large monocytc-derived repre sentatives of the mononuclear phagocyte system are found both on the surface of alveolar septa and in the interstitium. Macrophages are important in removing any debris that escapes the mucus and cilia in the conducting portion of the system.

They also phagocytose blood cells that enter the alveoli as a result of heart failure. These alveolar macrophagcs, which stain positively for iron pigment (hemosiderin), are thus designated heart failure cells.

ALVEOLI

Occurring only in the respiratory portion (which their presence distinguishes from the conducting portion), these small (about 200 um in diameter) sacs open into a respiratory bronchiole, an alveolar duct, an atrium, or an alveolar sac. They are separated by thin walls termed interalveolar (or alveolar) septa.

A. Interalveolar Septa: The structural features of these septa, which are specialized for gas exchange, are critical to respiratory function. The septa consist of 2 simple squamous epithelial layers with the interstitium sandwiched between them. The interstitium consists of continuous (nonfenestrated) capillaries embedded in an elastic connective tissue that includes elastic and collagen fibers, ground substance, fibroblasts, mast cells, macrophages, leukocytes, and contractile interstitial cells that contract in response to epinephrine and histamine. This elastic tissue is an important component of the ventilating mechanism. Gas exchange occurs between the air in the alveolar lumen and the blood in the interstitial capillaries.

1. Blood-air barrier. This term refers to the structures that oxygen and CO2, must cross to be exchanged. Varying from 0. 1-1.5 um in thickness, it includes the following layers: a. The film of pulmonary surfactant on the alveolar surface. b. The cytoplasm of the squamous cpithelial (type I alveolar) cells. c. The fused basal laminae sandwiched between the type I alveolar and capillary endothelial cells. d. The cytoplasm of the squamous endothelial cells lining the intcrstitial capillaries.

2. Alveolar pores. Each septum may be interrupted by one or more pores from 10 to 15 um in diameter. These connect adjacent alveoli and may help to equalize pressure and allow collateral air circulation, thus maximizing the use of available alveoli when some small airways are blocked.

BRONCHIAL TREE - 2

D. Bronchioles: These are branches of the smallest bronchi. The largest bronchioles differ from the smallest bronchi only by the absence of cartilage and glands in their walls. Large bronchioles are lined by typical respiratory epithelium; as they branch further, the epithelial height and complexity decrease to simple ciliated columnar or cuboidal. Each bronchiole gives rise to 5-7 terminal bronchioles.

E. Terminal Bronchioles: The smallest components of the conducting portion of the respiratory system, these are lined by ciliated cuboidal or columnar epithelium and have few or no goblet cells. The lining here also includes dome-shaped cilia-free Clara cells, whose cytoplasm contains glycogen granules, lateral and apical Golgi complexes, elongated mitochondria, and a few secretory granules. The function of these cells is unclear. Each terminal bronchiole branches to form 2 or more respira tory bronchioles.

F. Respiratory Bronchioles: These are the first part of the respiratory portion, with a cuboidal epithelial lining which resembles that of the terminal bronchioles but which is interrupted by thin-walled saccular evaginations called alveoli. The number of alveoli increases as the respiratory bronchioles proceed distally. As the alveoli increase in number, the cilia decrease until they disappear. Goblet cells are absent.


G. Alveolar Ducts: These are simply the distal extensions of the respiratory bronchioles where the alveoli are so dense that the wall consists almost entirely of these sacs, and the lining has been reduced to small knobs of smooth muscle covered by cilia-free simple cuboidal cells.

H. Atria and Alveolar Sacs: Atria are the distal terminations of alveolar ducts. The arrangement is comparable to a long hallway (alveolar duct) leading to a rounded foyer (atrium). The foyer has small doorways leading to some small rooms (alveoli), but also has 2 or more larger doorways leading into short, dead-end hallways (alveolar sacs). The short hallways are also lined by small rooms (alveoli). Put simply, the difference between atria and alveolar sacs is that the atria open into alveolar ducts, alveoli, and alveolar sacs, while the alveolar sacs open only into alveoli and atria.

BRONCHIAL TREE

This begins where the trachea branches to form 2 primary bronchi, one of which penetrates the hilum of each lung. The hilum is also the site at which arteries and nerves enter and veins and lymphatic vessels exit the organ. These structures, together with the dense connective tissue that binds them, form the pulmonary root. The bronchial tree undergoes extensive branching within the lungs. The changes in wall structure that accompany the progress of the bronchial tree toward the alveoli occur gradually and not at sharp boundaries.

A. Primary Bronchi: There are 2 primary bronchi, one entering each lung. Their histologic appearance is quite similar to that of the trachea, but their cartilage rings and spiral bands of smooth muscle completely encircle their respective lumens. The path of the right primary bronchus is more vertical than that of the left. As a result, foreign objects that reach the bronchi are more likely to lodge in the right side of the bronchial tree.

B. Secondary Bronchi: These lobar broncbi are branches that arise directly from the primary bronchi; each supplies one pulmonary lobe. Since the right lung has 3 lobes and the left only 2, the right primary bronchus gives rise to 3 secondary bronchi and the left primary bronchus gives rise to 2. Their histologic structure is similar to that of the primary bronchi except that their supporting cartilages (and those of the smaller bronchi) are arranged as irregular plates, or islands, of cartilage, rather than as rings.

C. Tertiary Bronchi: Arising directly from the secondary bronchi, which they resemble histo logically, each of these segmental bronchi supplies one bronchopulmonary segment (pulmonary lobule). Although each lung has 10 such segments, the different number of secondary bronchi causes the tertiary branching pattern to differ between the right and left lungs. Except for a decrease in overall diameter, the histologic appearance of tertiary bronchi is identical to that of secondary bronchi. Tertiary bronchi may branch several times to form successively smaller branches, which are considered bronchi as long as their walls contain cartilage and glands.

TRACHEA

This 10-cm tube extends from the larynx to the primary bronchi. It is lined by respiratory epithelium, and its lamina propria contains mixed seromucous glands that open onto its lumen. Its most characteristic feature is the presence of 16-20 C-shaped cartilage rings whose open ends are directed posteriorly. The opening is bridged by a fibroelastic ligament that prevents overdistension as well as by smooth muscle bundles (tracbealis muscle) that constrict the lumen and increase the force of air flow during coughing and forced expiration.

Respiratory System Picture

This picture shows all respiratory system members, respiratory tracts and ways.

Respiration occurs in following way from external surface to inner surface: Nasal cavity -pharnyx- trachea - bronch - bronchioles - arteries

The Details of these systems coming.

GENERAL FEATURES OF THE RESPIRATORY SYSTEM

A. Components and Basic Functions of the Respiratory System: The respiratory system includes the lungs, airways tie, pharnyx, larynx, trachea, bronchi) and associated structures. Specialized for gaseous exchange between blood and air, including the uptake of oxygen and release of carbon dioxide, it is functionally divisible into 2 major parts: the conducting and respiratory portions.

1. Conducting portion. The walls of this system of tubes are specialized to carry air to and from the site of gas exchange without collapsing under the pressures created by the ventilating mechanism. This portion also conditions the air, warming, moistening, and cleaning it to enhance gas exchange. It includes the nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.


2. Respiratory portion. This portion is distinguished by alveoli, small, saccular structures whose thin walls enable the gas exchange between air and blood. Alveoli occur in clusters at the end of the bronchial tree. These clusters extend (like rooms from a hallway) from the walls of respiratory bronchioles, alveolar ducts, and atria and alveolar sacs.


B. Wall Structure: Like the digestive tract, the tubelike respiratory tract has layered walls whose lining epithelium derives from endoderm. The wall layers include an epithelium, a lamina propria that contains mucous glands as well as cartilage that prevent the tract from collapsing under pressure, smooth muscle that regulates the luminal diameter, and an adventitia that contains collagen and elastic fibers. Respiratory epithelium

a. General features. The epithelium lining most of the tract is ciliated pseudostratified columnar with goblet cells; it is generally referred to as respiratory epithelium. As the respiratory tract undergoes branching and its luminal diameter decreases, the epithelium gradually drops in height and loses first goblet cells and then cilia as it approaches the alveoli.

b. Epithelial cell types :

(1) Ciliated columnar cells predominate in the tract. Each has about 300 motile cilia on its apical surface; there are associated basal bodies in the apical cytoplasm.
(2) Mucous goblet cells are the second most numerous type. They secrete the mucus that covers the epithelium and traps and removes bacteria and other particles from inspired air. Cilia projecting from columnar cells sweep the contaminated mucus toward the mouth for disposal. (3) Brush cells. Also columnar, these cells lack cilia; they often have abundant apical microvilli. Two types are present: One resembles an immature cell and apparently serves to replace dead ciliated or goblet cells; the other has nerve endings on its basal surface and appears to be a sensory receptor.
(4) Basal cells. These small round cells lie on the basal lamina but do not reach the lumen. They appear to be stem cells that can replace the other cell types.

c. Metaplasia refers to the change in tissue organization or type undergone by epithelia in response to changes in the physical or chemical environment. For example, a smoker's respiratory epithelium typically develops more goblet cells in response to high pollutant levels and fewer ciliated cells in response to carbon monoxide. These changes, which are reversible, frequently cause congestion of the smaller airways.