Collections II: Entomology Respiration & Circulation.
-
Upload
kristopher-lynch -
Category
Documents
-
view
214 -
download
0
Transcript of Collections II: Entomology Respiration & Circulation.
Collections II: Entomology
Respiration
&
Circulation
Insect Respiration Overview:
Waterproof cuticle = permeable to water and oxygen by diffusion
System of internal branching tubes (trachea): Very fine branches (tracheoles) penetrate
individual cells Trachae have spiral stiffening - like vacuum
cleaner hose - to prevent collapse.
Tracheal System of a Cockroach
Oxygen Pathway:
Air enters from the outside through a series of openings (spiracles)
Typically 2 pair of spiracles on the thorax and 8 pair on the abdomen
Pathway of oxygen = O2 from spiracles --> tracheae --> tracheoles
--> cells
Water loss and additional respiratory structures:
To avoid water loss through spiracles: opening and closing devices filtering lobes or hairs before trachea
Active insects: Internal air sacs extra reservoirs Mechanical ventilation (using specialized
valves) along the larger trachae Bees and wasps extend their abdomens to pump
air across
Spiracles
trachea
Insects could have one or more to aid in aquatic respiration:
tubes connecting to the air at the water surface
hydrofuge hairs (water resistant) associated with the spiracles to keep water out
tracheal gills whereby oxygen diffuses from the water to fine surface
trachae. bubble of air hemoglobin Directly diffuse oxygen across their cuticle. spiracles at the end of siphons
open into the trachae/penetrate the skin of their host
The Circulatory System Overview:
Open circulatory system = blood (haemolymph) flows freely through the body cavity (haemocoel)
There is a dorsal vessel = closed at the end of the abdomen and opens in the head (aorta).
several chambers valve-like openings (ostia) pumped forward to the aorta and into the body
cavity
Blood Overview:
Blood contains: Water - about 90% Inorganic ions - dissolved salts of Na, K, Ca,
Mg. organic molecules - amino acids, sugars for
muscle use Blood cells does not generally contain hemoglobin
Function of Blood:
Lubricant Hydraulic medium - can transfer forces to
different parts of the bodyTransport - sugars, fats, proteins, wastes,
hormones Protection (blood cells) Defense (rare)
Rate of Blood Flow:
helped by general muscular contractions and movement
pumping muscles on either side of the dorsal vessel in active insects, additional pumping organs at the
bases of the wings legs and antennae The pulse rate is controlled by hormones and
varies with temperature/activity The open circulatory system is inefficient
Injected Dye 5 minutes to permeate the insect…less than 1 minute in humans