1. Introduction to Respiratory System
What are the functions of the respiratoy system?
Getting gases in and out… Environment to blood = external Blood to tissues = internal
Olfaction and communication
What structures are necessary?
Respiratory membranes (highly vascular, thin, moist and large surface area)

2. Introduction to Respiratory System
How does your nose contribute?
Olfactory epithelium
Speech… Sinuses Cavities or spaces in bones of skull, empty into the nasal cavity to provide resonance.
Sinusitis inflammation of membranes lining sinus cavities

3. Respiratory System: Gills
What features are peculiar to Agnathans?
What all (?) have vertebrates have in common… Pharyngeal pouches meet ectodermal grooves… the branchial membrane then ruptures forming gill slits
In Hagfishes afferent and efferent branchial ducts carry water towards and away from the pharyngeal or gill pouches

4. Respiratory System: Gills
What features are peculiar to Agnathans?
Lamprey are tightly attached to host/prey…
External nare ends in a blind sac. Consequently, they pump water in and out via the external gill slits.
Respiratory tube facilitates breathing and feeding.

5. Respiratory System: Gills
What features are peculiar to Chondrichthian fishes?
Chondrichthian fishes have a spiracle and often 5 pairs of gill pouches except for Hexanchus and Heptanchus
Spiracle of skates and rays primary incurrent, major in most sharks, but minor or lost in fast swimming species
Naked gills (no operculum)

6. Respiratory System: Gills
What features are peculiar to Chondrichthian fishes?
Demibranchs are the vascular layers found in gill chambers
Pre- and posttrematic demibranchs are supported by an interbranchial septum

7. Respiratory System: Gills
What features are peculiar to Chondrichthian fishes?
Holobranchs support and provide structure for primary vasculature
Gill rakers guard the slit

8. Respiratory System: Gills
What features are peculiar to Chondrichthian fishes?
Countercurrent flow of water and blood from ventral aorta facilitates diffusion.
Lamella increase surface area (primary and secondary)

9. Respiratory System: Gills
What features are peculiar to Chondrichthian fishes?
Water flows in via spiracle and mouth (inspiration 1) when branchimeric muscles expand the pharyngeal chamber.
Mouth closes and hypobranchial muscles make the gill chamber expand (inspiration 2)
Constrictors decrease volume of gill chamber forcing water out gill slits (expiration)

10. Respiratory System: Gills
What features are peculiar to Bony fishes?
Pharyngeal arches support holobranchs.
Presence of operculum a major difference.
Gills occur in an opercular chamber.
Mouth opens, pharyngeal floor lowers (opercula closed) (inspiration) Opercular chamber volume increases as opercula open
Constrictors decrease volume of opercular chamber forcing water out opercular cleft (expiration)

11. Respiratory System: Gills
What other functions do gills serve?
Excretion… salts in marine fish, nitrogenous wastes in all fish and CO2 even in lungfish

12. Respiratory System: Gills
What features are peculiar to larvae?
3 types: External gills found on larval amphibians and a few types of fish
Filamentous extensions (internal) found on chondrichthian fishes
Internal gills unique to later staged tadpoles

13. Respiratory System: Gills
What features are peculiar to larvae? External gills
Internal gills

14. Respiratory System: Nasal structures
What is the role of the nares in most fish?
External nares have anterior and posterior regions (incurrent and excurrent aperatures respectively). The passageway leads to blind sacs used for olfaction
Lobe-finned fishes the nasal cavities communicate with the pharynx via internal nares

15. Respiratory System: Swim bladders
How are foregut evaginations related to lungs in humans?
These sacs store gases taken directly from the atmosphere (physostomous) or from the blood with no connection to the pharynx (physoclistous)
The gas can be N2, O2, usually some CO2 and/or Argon
Serve as buoyancy devices, also help detect sound.

16. Respiratory System: Swim bladders

17. Upper Respiratory System
How are foregut evaginations related to lungs in humans?
The lung bud is a single evagination that communicates with the pharynx via the glottis
It bifurcates and pushes caudad until they are beside the heart
Lung bud tissue between lungs and glottis become larynx, trachea and bronchi

18. Upper Respiratory System: Larynx

19. Upper Respiratory System: Larynx
What are the functions of the larynx?
Functions to control entrance to trachea and to allow speech
Comprised of several cartilages…
Tracheotomy or Cricothyrotomy

20. What are the functions of the larynx?
BI 203 Human Anatomy & Physiology II
What are the functions of the larynx?

21. Upper Respiratory System: Larynx
What are the functions of the larynx?
Resonating chambers and snorkels

22. Upper Respiratory System: Larynx
Since birds don’t have a larynx… how do they make noise?
They pass air through a structure (syrinx) just cephalic to bronchi.

23. Lower Respiratory System: Lungs

24. Lower Respiratory System: Lungs
What special adaptations do birds have?

25. Lower Respiratory System: Lungs
What special adaptations do birds have?

26. Lower Respiratory System: Lungs
What special adaptations do birds have?

27. Lower Respiratory System: Lungs

28. Lower Respiratory System: Lungs
How do the components of alveoli differ?
* Macrophages
* Type I pneumocytes
* Type II pneumocytes