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24 Cards in this Set

  • Front
  • Back
What is the difference between internal and external respiration?
Internal respiration takes place between capillary beds and the tissues or cells of the body. External respiration is the gas exchange that takes place between the respiratory organs and the environment.
What increases diffusion of gases in the respiratory system?
1)Providing a large surface area between the environmental media (water or air) and the blood
2) Reducing the thickness of the barrier between medium and blood
3)Maintaining the contact of each blood cell with the medium for an adequate time
4)establishing for each gas a large diffusion gradient between medium and blood
5)countercurrent of blood and medium
What is ventilation?
The pumping of water in gills or of air in lungs.
What is cutaneous respiration and what organism use it?
Respiration through the skin or epidermis.
Effective for small vertebrates with low levels of activity, that live in cool flowing water or damp air.

Salamanders, frogs, tadpoles, some kinds of fish
What are internal gills?
Gills which lie within the contour of the head.
What does the first pharyngeal pouch become?
The spiracle in tetrapods the middle ear cavity.
What is the first closing plate in tertrapods?
The ear drum.
What kind of gills do sharks have?
Septal gills. Have gill septa that serve as supportive tissue.
What kind of gills do most teleost fish have?
Opercular gills, because they have an operculum which covers the gills.
What is the function of gill rakers?
Gill rakers prevent food from entering the gill chambers as it passes through the pharynx.
What is a holobranch?
A single gill bar with
anterior and posterior rows of respiratory filaments
What is a hemibranch?
A single gill bar that only bears filaments on one surface.
What is a pseudobranch?
Filaments that are modified to serve a nonrespiratory function.
What are fishes with septal gills called?
Besides oxygen and carbon dioxide exchange, what else do gills do?
Function in the excretion and osmoregulation. In fact bony fishes excrete almost all of their nitrogenous waste through the gills.
What are pouched gills?
Gills characteristic of agnatha. The gill filaments are arranged over the surface of discrete spherical or lenticular pouchlike gill chambers. May have an external pore to the surface of the body or they might have a common duct or pore.

Each pouch also has an internal pore to communicate with the pharynx or with a division of the pharynx that is seperate from the food path.
How are septal gills different from other types?
-have larger gill chambers than pouched gills
-communicate more widely with pharynx than pouched
-communicate to outside via verticle gill slits instead of pores
-have gill septa
Describe the relationship between gills and water?
Since water contains much less oxygen than air, and diffusion is very much slower, effective ventilation of the gills is essential, yet the greater density and viscosity of water place a greater burden on the ventilation apparatus.

Cyclostomes; flow through gills can be accomplished through the mouth or like the tide, passing through the lamellae in only on direction.

Water is actively expelled from pouches by muscular contraction.

Sharks draw water in through mouth and spiracles. Accomplished by elastic recoil of the viseral skeleton following contraction of the phayrnx, hypobranchial muscles may contribute. Some other stuff happens too to make the suction.

Opecular gills are similar in this respect to septal gills.
Warm vs Cold water
Warm or stagnant water contains less oxygen than cold or moving water.

In oxygen poor water fish may turn in part to aerial respiration.
What are lungs?
Internal organs derived from the gut tube that are filled with air and function primarily in respiration. Whether they are paired or not. Internal organs filled with air but not used for respiration are called gas bladders. These are only in bony fish.
What do we know about the origin of lungs?
1) date back to the Devonian period
2)lungs were initially paired lateral organs that developed in series with the phayngeal gill pouches
What do we know about the origin of lungs?
1) Dates back to the Devonian period
2)Lungs were initially paired lateral organs that developed in series with the phayrngeal pouches
3)ancient organs shifted ventrally to form the respiratory structures of tertapods, dipnoans, and some primitive ray-finned fishes
4)In most ray-finned fishes either the ancient paired organs shifted dorsally to merge over the gut and become a single bladder, or one of the initial lungs was lost, leaving the other to shift around the gut to left or right.
What is the pneumatic duct and why is it important?
The embryonic lung or gas bladder is always joined to the gut by a pneumatic duct. If the organ is to be a lung the duct is retained.

Such a lung or bladder is called a physosotmous.

Gas bladder with out duct is called a physoclistous.
What does a gas bladder do?
Allowes the fish to swim upright without muscular effort. Gas is secreted into the bladder from the blood.