Summary on circulatory system of most insects

2. The Insect Circulatory System
0 Insects have an open circulatory
system.
0 The hemocoel is filled with
hemolymph that bathes the organs
0 Insects have local pulsatile organs at
the bases of appendages that pump
hemolymph
0 It does not carry oxygen along its
circulation.

3. Insect Circulatory Organs
DORSAL VESSEL
0 principal organ responsible for blood circulation
0 lies along the dorsal midline of the insect body
HEMOCOEL
0 the compartmentalized structure of this cavity is due
to the presence of one or two fibromuscular septa

4. Insect Circulatory Organs
HEART
0 usually closed at its posterior end and bears a number
of valvular openings (ostia)
ALARY MUSCLES
0 fibromuscular innervated structures attached laterally
to the body wall and vary in number from 1-13 pairs

5. Insect Circulatory Organs
HEMOLYMPH
0 Colorless liquid that bathes the insect tissues
0 Only about 10% are hemocytes and the rest of the
hemolymph content is watery plasma
0 Known functions:
- phagocytosis
- coagulation
- encapsulation of foreign objects
- wound healing

6. Insect Circulatory Organs
HEMOLYMPH COMPOSITION:
0 90% Water
0 Inorganic ions
0 Nitrogenous wastes
0 Carbohydrates
0 Lipids
0 Proteins and enzymes
0 Pigments
0 Hormones

7. Insect Circulatory Organs
HEMOLYMPH FUNCTIONS:
0 Lubricant for tissues and internal organs
0 Hydraulic medium (caterpillars, wing expansion, etc.)
0 Transport medium for nutrients, wastes and hormones
0 Storage (amino acids, water, and glycerol)
0 Heat exchange
0 Immune response

8. Circulation
0 When the heart contracts,
the valves of the ostia are
closed by the pressure and
the hemolymph is moved
forward and dumped into
the head area.
0 Alary muscles aid the
contractions of the heart.

9. Circulation
0 The blood circulation is also aided by the presence of
the dorsal and ventral diaphragms, which consists of
sets of muscles that divide the hemocoel into various
sinuses.

10. The Insect Circulatory System

11. Overview
VERTEBRATES INSECTS
0 Closed circulatory
system
0 Blood
0 Heart
0 Oxygen
Transportation
0 Open circulatory
system
0 Hemolymph
0 Dorsal Vessel
0 Transport of other
substances

12. References
http://home.sandiego.edu/~gmorse/2010BIOL348/Bi
ol348_Website/Lectures/2010_02_15_lecture_4.pdf
http://www.faculty.ucr.edu/~insects/pages/teachingre
sources/stoffolano/2.pdf
http://insects.about.com/od/morphology/ss/internala
natomy_4.htm