Download Respiratory Systems

Respiratory Systems
• Respiration is the process of gas exchange
• Cellular respiration is the process of energy
production
• Respiratory membranes - highly vascular,
moist surfaces in contact with environment
• Respiratory organs - integument, gills and
lungs. May also include outgrowths of
pectoral fins, trunk or thigh and mucosa of
oropharynx, esophagus, stomach, intestine,
rectum or anus
Gills
(Walls of pharyngeal pouches)
• Agnathans - 5-7 pairs of vascularized,
internal gill pouches supplied by afferent
and efferent branchial ducts
• Cartilaginous fish - usually 5 pairs of gill
pouches; functional gill surfaces are
demibranchs -pretrematic and posttrematics;
spiracle supplies water in most species
• Bony fish - similar pattern to shark. Gill
chamber protected by bony operculum
• Larval gills - external, internal or internal
projecting through gill slits. Gills are
usually reabsorbed during metamorphosis in
amphibians - exception is neotany
• Gills may also serve an excretory function
by eliminating nitrogenous wastes and CO2;
chloride cells regulate salt balance
migrating species of fish.
Air breathing in bony fish
• Many fish gulp air from surface of water
• Oxygen by be absorbed through
oropharyngeal mucosa of swim bladder
• Carbon dioxide eliminated through gills
Nares and nasal canals
• First seen in cartilaginous fish
• Direct water to gills; not used to breathe
• Nasal passeges arise from paired nasal pits
and nasolabial (orolabial) grooves which
close to form a tube. Blowholes in whales
are really nostrils
• In humans, severe facial anomalies occur if
fusion fails or is incomplete
Swimbladders
• Form from evagination of esophagus or
pharynx
• Function as hydrostatic organs
• Gas comes from blood through rete mirable
by active transport
• These structures also function in hearing
Lungs
• Arise from evagination of ventral pharynx
(opening forms glottis)
• Larynx containg vocal folds lies between
glottis and trachea
• Trachea bifurcates into primary bronchi
serving each lung (at this bifurcation lies the
syrinx in birds)
• Lungs may occupy the abdominal cavity or
only the thorax if a diaphragm is present.
• Diaphragm serves to inflate lungs
• Lungs may be simple sacs or more
complicated structures containing septa or
minute sacs known as alveoli.
• Reptiles have lung diverticula forming air
sacs
• Birds have lung diverticula extending into
bones (hollow)
• Mammalian lungs are lobes and consist of
functional units known as alveoli (alveolus)
• In all lungs, gas exchange occurs by simple
diffusion