Zoology 484 M.P.Wenderoth

Nov.10-12 , 1997

Readings: Randall Chapter 13

-Recap material covered in first lecture on respiration

I. -Respiration in a water environment

A.. The Vertebrate Gill ----

1. Functional anatomy of the gill (fig 13-45)

2. Ventilation of the gill (fig 13.44)

• pressure pump--suction pump
• ram ventilation

B. Respiration via the skin in vertebrates

• amphibians--skin breathers
• reptiles--impermeable skin
  

Basic anatomy of lungs (fig 13-21)

tubes (trachea, bronchioles) transport air to respiratory surface

sacs--(alveoli) --respiratory epithelium .2m thick

amphibians---reptiles---birds/mammals

decrease size of sacs and increase number of sacs

The Insect Tracheael System

Anatomy of tracheae (fig 13-38)

spiracles-trachea-tracheoles-cell membrane

Ventilation:

diffusion--very rapid in air vs. water

During increased metabolic demand can "ventilate"

Amphibians

• saccular lungs
• positive pressure breathers
• tidal ventilation

Reptiles: Origin of Aspiration Breathing

• saccular lungs to highly branched lungs
• no diaphragm but other body muscles used in inhalation
• tidal ventilation
  

Avian:--later

Mammalian

Anatomy of lung (13-21 +29)

extensive branching, large numbers of very small alveoli

surface area increases with rate of oxygen consumption

lung volume = 5% of body

Respiratory Membrane in alveoli

components

surfactant decreases surface tension

Ventilation

tidal, negative pressure, diaphragm main muscle of insipiration

Boyle's Law ------P1*V1 = P2 * V2

Regulation of Ventilation

PCO2 levels of blood (respiratory center of medulla [brain stem])

Scaling of ventilation rate, lung volume, respiratory frequency with body mass

Avian Respiration

ventilation in birds (fig 13-32,33)

parabronchiole system and air sacs allow unidirectional air flow

blood flow through the lung --cross current

blood leaving avian lungs can have higher PO2 than expired air