Changes

==Fish==

==Fish==

When a fish breaths, it takes in water into the mouth, which is then forced out through the gills. A '''countercurrent exchange''' system is in place within the gills to make gaseous exchange more efficient.

When a fish breaths, it takes in water into the mouth, which is then forced out through the gills. A '''countercurrent exchange''' system is in place within the gills to make gaseous exchange more efficient.

In amphibian species, the [[Skin - Anatomy & Physiology|skin]] forms the major, and sometimes only respiratory organ.

The anatomic structure of the gills helps in its functions by providing a '''large and very thin surface'''. The gill filaments are divided into multiple finger-like projections, the primary lamellae, which in turn are divided into secondary lamellae.

The [[Skin - Anatomy & Physiology|skin]] of amphibia is:

There is usually very little mucus on the gill surface.

Most Amphibia also have lungs for breathing. This contains interconnecting septa which divide the lumen into '''Faveoli''', compartments which open into a central chamber within each [[Lungs - Anatomy & Physiology|lung]].

In amphibian species, the [[Skin - Anatomy & Physiology|skin]] forms the major, and sometimes only respiratory organ. The skin of amphibia is thin, poorly keratinised, highly vascularised and moist to promote diffusion of gases. '''Aquatic''' amphibians may also have ''internal gills'' and '''pharyngeal slits'''. Most amphibia also have lungs for breathing. This contains interconnecting septa which divide the lumen into '''faveoli''', compartments which open into a central chamber within each [[Lungs - Anatomy & Physiology|lung]].

==Reptiles==

==Reptiles==

Reptiles have a fundamentally different respiratory system to that of mammals, in that they lack a bronchial tree.

Reptiles have a fundamentally different respiratory system to that of mammals in that they lack a bronchial tree.  

 

The air in the reptilian respiratory system flows through the following passage:

Route of Air in the Reptiliant Respiratory System:

#Air enters via nares

#Air enters via nares

#[[Nasal Cavity - Anatomy & Physiology|Nasal Cavity]]

#[[Nasal Cavity - Anatomy & Physiology|Nasal Cavity]]

#Lungs

#Lungs

The lungs are paired, with respiration only occuring in the cranial region.

The lungs are paired, with respiration only occurring in the cranial region. The respiratory surface is composed of '''faveoli''', honeycomb shaped structures which line the walls. In addition, reptiles have a poorly developed mucocillary escalator, and rely on body positioning to clear mucous from the respiratory system.

 

The Respiratory surface is composed of '''Faveoli''', honeycomb shaped structures which line the walls.

 

In addition, reptiles have a poorly developed mucocillary escalator, and rely on body positioning to clear mucous from the respiratory system.

===Lizards===

===Lizards===

*No diaphragm

Lizards have no diaphragm and a simple, sac-like, paired [[Lungs - Anatomy & Physiology|lungs]]. The cranial part of lung is the site of respiratory function. The caudal part of the lung forms an air ''reservoir''. Ventilation occurs via expansion and contraction of the ribs. For more information see [[Lizard and Snake Respiration]] and [[Lizard Respiratory System]].

*Simple, saclike, paired [[Lungs - Anatomy & Physiology|lungs]].

*Cranial part of lung is site of respiratory function

*Caudal part of lung forms air ''reservoir''

*Ventilation occurs via expansion and contraction of the ribs

 

For more information see: [[Lizard and Snake Respiration]] and [[Lizard Respiratory System]].

===Snakes===

===Snakes===

*Larynx projects medially from the floor of the mouth and is fused with the first few cartilage rings of the trachea. This forms a rigid '''Glottis''' which is highly  mobile and can be displaced laterally to allow breathing during feeding.

The larynx projects medially from the floor of the mouth and is fused with the first few cartilage rings of the trachea. This forms a rigid '''glottis''' which is highly  mobile and can be displaced laterally to allow breathing during feeding. The tongue is fixed at the rostral point of the oral cavity. Generally, only the right lung is present, or at least functional - ''colubrids'' have a vestigial left lung. The lung of snakes is very fragile. Inspiration is an active process, made possible by expansion of the ribs. It occurs approx once every 30 seconds in large, healthy snakes. Expiration is a passive process. Snakes have no vocal cords, but are able to make hissing noises by passing air through the glottis. Aquatic snakes have air sacs which serve as a buoyancy aid. For more information see [[Lizard and Snake Respiration]] and [[Snake Respiratory System]].

*Tongue is fixed at the rostral point of the oral cavity.

*Generally only the right lung is present, or at least functional - ''colubrids'' have a vestigial left lung. The lung of snakes is very fragile.  

*Inspiration is an active process, made possible by expansion of the ribs. It occurs approx once every 30 seconds in large, healthy snakes. Expiration is a passive prcoess.

*Snakes have no vocal cords, but are able to make hissing noises by passing air through the glottis.

*Aquatic snakes have an air sacs which serves as a bouyancy aid.

 

For more information see [[Lizard and Snake Respiration]] and [[Snake Respiratory System]].

===Chelonians===

===Chelonians===

*Chelonians have adapted a '''dive reflex''' which enables them to respire anaerobically. They have extremely high levels of bicarbonate in their blood which allows them to buffer the lactic acid produced.

Chelonians have adapted a '''dive reflex''' which enables them to respire anaerobically. They have extremely high levels of bicarbonate in their blood which allows them to buffer the lactic acid produced. Chelonians have an extremely short trachea in relation to their size. They have paired lungs in the '''dorsal cavity'''. Intestines etc. lie in the '''ventral cavity'''. These are separated by a diaphragmatic septum which has no muscular part. Chelonians possess large spongy lungs which reduce 80% in size when the head and limbs are retracted inside the shell. The lungs have a single intrapulmonary bronchus which radiates in a network of bronchioles and faveoli. Lungs are ventilated by leg movement in terrestrial animals, and have highly developed trunk muscles to facilitate this. Aquatic species are able to respire due to the hydrostatic pressure of water, which forces air in and out of the lungs. In addition, some soft-shelled chelonians are able to absorb oxygen through their shells and skin when submerged.

*Chelonians have an extremely short trachea in relation to their size.

*Chelonians have paired lungs in the '''Dorsal Cavity'''. Intestines etc lie in the '''Ventral Cavity'''. These are separated by a diaphragmatic septum which has no muscular part.

*Possess large spongy lungs which reduced 80% in size when the head and limbs are retracted inside the shell.The lungs have a single intrapulmonary bronchus which radiates in a network of bronchioles and faveoli.

*Lungs are ventilated by leg movement in terrestrial animals, and have highly developed trunk muscles to facilitate this. Aquatic species are able to respire due to the hydrostatic pressure of water, which forces air in and out of the lungs. In addition, some soft shelled chelonians are able to absorb oxygen trhough their shells and skin when submerged.

 

[[Category:Respiratory System - Anatomy & Physiology]]

[[Category:Respiratory System - Anatomy & Physiology]]

[[Category:To Do - A&P]]

[[Category:A&P Done]]