unit 8 Flashcards
primary function of the respiratory system
exhcnage gasses with the environment to obtain suffiecient oxygen and sexrete suffiecient carbon dioxide
ventilation
moving air or water across the gas exchange surface
perfusion
pumping blood through the capillaries of an organ, in this case the capillaries of the gas exchange surface
diffusion
spontaneous movement of molecules/atoms from a region of high concentration to low concentration
adaptations to increase diffusion rate
large surface area
thin tissue
high vascularization
dV/dt
diffusion rate. volume of gas moving through a given area in a given amount of time
A/dx
A: surface area
dx: thickness of tissue
D
constant diffusion rate
(P1-P2)
partial pressure gradient.
P1: partial pressure of oxygen in the alveoli
P2: partial pressure of oxygen in the blood passing through the capillaries
pathway of air in mammals
air is drawn through the trachea and enters the lungs through bronchi and bronchioles
how do bronchioles end
tiny saccular compartments called alveoli
what is special about the walls of alveoli
they are very thin and highly vascularized
in actinopterygii, sarcopterygii, and chondrichthyes what provides skeletal support for the gills
pharyngeal arches 3-7 of the splanchnocranium
gill rays
project from pharyngeal arches and support the interbranchial spetae
elasmobranchii interbranchial septae
complete interbranchial septaw which separate the parabranchial chambers
what creates the flap valve that covers the external gill slit
distal end of each interbranchial septum
where do primary lamellae project from
both sides of the interbranchial septum
what is on either side of the primay lamellae and what do they do
secondary lamellae. they are a site for gas exchange
what are the small projections on pharyngeal arches 3-7
gill rakers
what do gill rakers do
project into the pharynx forming a screen across the openings to the parabranchial chambers. this prevents food from entering these chambers and damaging the gills
what taxa have gill rakers
chondrichthyes and actinopterygii
where are elasmobranchs gills located
in parabranchial chambers
what separates the parabranchial chamber
complete interbranchial septum
where are actinopterygii gills
opercular chamber
what type of gills do larval amphibians have
external gills
tidal flow
not all the inhaled air reaches the gas exchange surface. not all of the air within the respiratory system is expelled during exhalation. some spent air remains such that the air inhaled during the following inhalation is a mix of the spent and fresh air
unidirectional flow
all of the inhaled air or water passes over the gas exchange surface such that there is little to no dead space
air breathing organs in actinopterygii
reinforced gills vascularized bucca or pharyngeal cavity buccal and pharyngeal diverticula specialized regions of the digestive tract swim bladder or lungs labrynth organ
labyrinth organ
located dorsal to the gills. formed by extensive folding of one of the dorsal bones of the pharyngeal arch 3
faclutatice breathing
actinopterygii and sarcopterygii
have gills and air breathing organs. gills are used when there is lots of oxygen in water, and air is used when not lots of oxygen in the water
obligate breathing
some actinopterygii and sarcopterygii.
gills are greatly reduced so that even with lots of oxygen in the water the gills will not work for breathing, they need to access teh air to breathe.
tetrapod breathing organs
lungs for air.
small compartments in lungs
faveoli. all open into hollow chamber in the center of the lung
how do amniotes ventilate their lungs
using an aspiration pump and tidal airflow
archosaurs airflow
unidirectional.
thrachea branches into two primary bronchi, which branches into secondary bronchi. they are connected via parabronchi
aves lungs
connected to a series of hollow elastic air sacs. expand when aspiration pump expands the thoracic cavity and compresses when aspiration pump compresses. parabronchi connects posterior air sacs to anterior
