Circulatory system of insect Open Circulatory system

By Department of Entomology student of The University of agriculture peshawar .

1. Circulatory System
of Insects
Presented by : Aleena Jalal

2. Circulatory System
A body system that circulate the blood
throught the body
Types
There are two types of circulatory
systems in animal kingdom i.e Open
Circulatory System and Close
Circulatory System

3. Close Circulatory
System
In close system the blood
stays inside the blood vessels
as it moves through the
body.
Example: Human beings etc.

4. Open Circulatory
System
In an open system the blood
(usually called hemolymph)
flow freely through body
cavities where it makes
direct contact with all
internal tissues and organs.

5. Organs of Insect
Circulatory System
1: Dorsal Blood Vessel
2: Haemocoel
3: Accessory Pulsating
Organs
4:Hemolymph

6. The Dorsal Blood Vessel
is the the main vessel
responsible for
circulating hemolymph
throughout the body.
This tube runs
longitudinally through the
thorax and abdomen,
along the inside of the
dorsal body wall.
Dorsal Blood Vessel

7. Comprises of two main
parts:
The posterior heart.
The anterior aorta.
Structure

8. The Heart
In the abdomen, the dorsal vessel is called the
heart.
It is divided into chambers that are separated by
valves-like openings (ostia) that allow one-way
flow of hemolymph from hemocoel.

9. Alary Muscles: A pair of alary muscles are
attached laterally to the walls of each chamber.
Role: Aid in the movement of hemolymph by
contracting and relaxing.
Contraction: Alary muscles contract, pulling the
heart open to facilitate filling with hemolymph.
Relaxation: Muscles relax, allowing the heart to
contract and pump hemolymph forward

11. The heart’s contraction rate varies considerably
from species to species — typically in the range of
30 to 200 beats per minute.
The rate tends to fall as ambient temperature
drops and rise as temperature (or the insect’s level
of activity) increases.

12. Aorta
The aorta specifically refers to the anterior portion of
dorsal blood vessel that extends from the heart (located
in the posterior part of the body) towards the head.
Unlike the heart, the aorta does not have valves or
pumping chambers; instead, it serves as a medium for
hemolymph to flow from the heart to various parts of
the body.

13. Aorta

14. Hemocoel
The hemocoel is the primary body cavity in insects.
Hemolymph circulates freely within the hemocoel, bathing
the internal organs directly.
It facilitates the transport of nutrients, waste products,
and hormones.

15. To facilitate circulation of hemolymph, the body
cavity is divided into three compartments ( sinuses)
by two thin sheets of muscle and/or membrane
known as the dorsal and ventral diaphragms.
.

17. Dorsal or Pericardial sinus : The area lying in
between tergum and dorsal diaphragm. It contain the
heart.
Ventral or Perineural sinus: The area lying in
between the sternum and ventral diaphragm. It
contain nerve cord.
Visceral sinus : The area between dorsal and ventral
diaphragms. It has visceral organs like alimentary
canal.

20. Accessory Pulsatile Organ
Accessory pulsatile organs in insects are additional
pumping structures that aid in the circulation of
hemolymph to specific body parts.
Location: Typically located at base of appendages like
antennae, wings and legs.
Function: Aid hemolymph flow to appendages, which may
not receive sufficient hemolymph through the dorsal
blood vessel.

21. Accessory Pulsatile Organ
Structure: Muscular pumps or contractile structures.
Mechanism: Rhythmic contractions create pressure for
hemolymph movement.
Necessity: Ensure adequate hemolymph supply to distant
appendages.
Coordination: They work in coordination with the main
circulatory system, ensuring a comprehensive and
efficient distribution of hemolymph throughout the
insect's body.

23. Hemolymph : Composition and Function
Hemolymph is insect blood.
watery fluid , usually clear but sometimes turn
greenish or yellowish in color.
Blood is not involved in oxygen transporting
function (respiration)
Hemolymph is red in Chironomid larvae.
Hemolymph = 90% plasma + 10% hemocytes

24. Composition of Hemolymph
1: Plasma
80-92% water
Ions (Na+, K+,mg2+ etc)
Proteins
Carbohydrates (Trehalose)
Fats
Uric acid ( insects are uricotalic )

25. 2: Blood Cells:
Prohemocytes: Small cells having a big nucleus help in making
new cells.
Plasmatocyte: These are phagocytic cells performing
phagocytosis ( cell eating ).
Granular hemocytes: Contain granules.
Coagulocytes : Clotting and wound healing in response to
injury of blood
Adipo-hemocytes: It has fat droplets ( help in storing fats)

27. Functions of Hemolymph
Nutrient Transport: Delivers essential nutrients from the
digestive system to the rest of the body.
Waste Removal: Carries waste products away from
cells to excretory organs for elimination.
Hormone Distribution: Transports hormones that
regulate growth, development, and reproduction.
Immune Response: Contains cells that fight off
infections and protect against pathogens.

28. Functions of Hemolymph
Hydraulic Medium : Hemolymph helps maintain turgor
pressure within the body, which is crucial for functions
such as molting (ecdysis), locomotion, and the extension of
limbs or other appendages.
Lubricant: Hemolymph lubricates the joints and soft
tissues of invertebrates, facilitating smooth and efficient
movement.

30. Reference :
Photos taken from google.
Presentation content taken from:
https://genent.cals.ncsu.edu/bug-bytes/circulatory-
system/
Hemolymph details: https://youtu.be/l-S62gRDEsI?
si=g16u6rgQ-ta1yFL-

31. Thank
you.