Circulatory System
Understanding the open type of circulatory system, haemocoel, tubular heart, and the composition and function of haemolymph.
What is Circulatory System?
A circulatory system in which blood (or haemolymph) is not contained entirely within a network of vessels, but flows freely through body cavities (haemocoel) bathing the organs directly.
Key points
- Describe the structure and function of the cockroach circulatory system.
- Differentiate between open and closed circulatory systems.
- Identify the components of the cockroach circulatory system (heart, haemocoel, haemolymph).
- Explain the flow of haemolymph within the body.
Common exam trap
Confusing the open system with a closed system.
Definitions
- Term
Open Circulatory System
- Meaning
A circulatory system in which blood (or haemolymph) is not contained entirely within a network of vessels, but flows freely through body cavities (haemocoel) bathing the organs directly.
- Term
Haemocoel
- Meaning
The primary body cavity of arthropods and some other invertebrates, containing the heart and circulating haemolymph.
- Term
Haemolymph
- Meaning
The circulatory fluid of arthropods and mollusks, analogous to blood, consisting of plasma and haemocytes.
- Term
Ostia
- Meaning
Small openings or pores, specifically referring to the openings in the heart of insects that allow haemolymph to enter from the haemocoel.
Learning objectives
Describe the structure and function of the cockroach circulatory system.
Differentiate between open and closed circulatory systems.
Identify the components of the cockroach circulatory system (heart, haemocoel, haemolymph).
Explain the flow of haemolymph within the body.
Prerequisites
Basic understanding of insect anatomy
Knowledge of body cavities and organs
Common mistakes
Confusing the open system with a closed system.
Assuming haemolymph carries significant amounts of oxygen.
Incorrectly identifying the location or structure of the heart.
Forgetting the role of ostia in haemolymph circulation.
Keywords
Circulatory system
Cockroach
Open circulation
Haemocoel
Dorsal heart
Haemolymph
Ostia
Arthropoda
Insect anatomy
Practice preview
Which of the following is NOT a component of the haemolymph in a cockroach?…
medium
In cockroaches, the circulatory system is of the type:…
easy
The heart of a cockroach is a long, tubular structure located:…
medium