In a way, yes. Shrimps are crustaceans. Based on how shrimp are built, their heart is on their thorax, right below the base of their head. The chest and head of a shrimp are fused together, making the chest look like a part of the head.
It’s much safer to protect their internal organ. Also, the shrimp’s heart, located in its head, has three pairs of heart entrances. Through these entrances, blood comes to the heart. The arteries extend for many directions.
There is often confusion regarding the difference between a shrimp and a prawn. Physically, they look very similar but there is one sure way to tell them apart. Shrimps have a side plate on the second part of their abdomen that overlaps the parts in front and behind it.
But, on the other hand, prawns have all the abdominal side plates overlapping tile-like from the front.
Shrimp are fascinating creatures that inhabit oceans and freshwaters around the world. With their small yet complex bodies, it’s easy to wonder – do shrimp have hearts? The answer is yes, but in a very unique way compared to vertebrate animals like humans.
In this article, I’ll cover everything you need to know about the circulatory system of shrimp and the role their heart plays. We’ll look at where their heart is located how it functions and how it compares to the human heart. By the end, you’ll have a clear understanding of the shrimp’s strange yet effective cardiovascular setup.
An Overview of the Shrimp Circulatory System
Unlike humans and other vertebrates, shrimp have an open circulatory system. This means that their blood flows freely within the body cavity rather than being restricted to blood vessels. The circulating fluid is called hemolymph. It performs the same basic functions as blood – transporting nutrients, oxygen, and waste products around the body.
At the center of the shrimp circulatory system is a single-chambered heart. Instead of the four chambered structure found in humans, the shrimp heart is a simple muscular tube. Despite its simple design, it efficiently circulates hemolymph throughout the shrimp’s body.
Three pairs of arteries carry hemolymph away from the heart to supply the body. The hemolymph then seeps through tissues before draining back to the heart through openings called ostia. This open system allows for easy oxygen and nutrient exchange.
The Shrimp Heart Structure
The shrimp’s heart is a long tubular structure located in the head region. It runs along the shrimp’s back, extending about two-thirds the length of its body. The muscular wall of the heart surrounds a central lumen through which hemolymph flows.
At the top end of the heart are three slit-like openings called ostia. These allow hemolymph to enter the heart. At the opposite end of the heart is an aorta for hemolymph to exit.
The ostia have valves that open when hemolymph flows into the heart and close to prevent backflow. Together with rhythmic contractions of the heart muscles, this allows only one-way flow of hemolymph from the ostia to the aorta.
How Does the Shrimp Heart Work?
The shrimp’s heart works through a sequence of muscle contractions and relaxations that pump hemolymph through the body. This sequence goes as follows:
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Ostia open as heart muscles relax, allowing hemolymph to flow into the heart lumen.
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Ostia valves close
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Heart muscles contract, increasing pressure inside the heart.
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This pressure forces the aorta open, pumping hemolymph out into arteries.
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Heart muscles relax again, lowering the pressure and causing ostia to open once more.
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The cycle then repeats about every second as the heart beats.
Although the overall circulatory path is simple, accessory pumps around the shrimp’s gills enhance blood flow in key areas. Valves ensure hemolymph always moves in the right direction.
Where is the Shrimp Heart Located?
The shrimp heart is tucked away inside the cephalothorax – the head section of the shrimp body. It runs along the shrimp’s dorsal midline from about the level of the stomach to two-thirds down the length of the abdomen.
Having the heart situated up front allows for better circulation to the cephalothorax, which houses the majority of the shrimp’s sensory organs and nervous system. Freshly oxygenated hemolymph can be quickly delivered from the gills to the brain and sensory organs, keeping them working optimally.
The forward position also places the heart closer to the feeding appendages, where fast circulation is needed when catching and handling food. At the same time, the heart extends back enough to supply the tail muscles which power swimming.
Shrimp vs. Human Heart
While shrimp and humans both need cardiovascular systems to circulate nutrients, oxygen, and waste, the designs are vastly different:
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Shrimp have a single chamber heart while the human heart has four chambers – two atria and two ventricles.
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The human heart is centrally located in the chest while the shrimp heart lies in the head region.
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Humans have a closed circulatory system with blood contained in veins and arteries. Shrimp have an open system with hemolymph free in cavities.
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The shrimp heart is much simpler in structure and beats around once per second. The human heart can beat 60-100 times per minute.
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Shrimp hemolymph lacks the red blood cells and hemoglobin that give human blood its red color.
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While the human heart powers a double circulatory loop, shrimp have a single system.
The Advantages of the Shrimp Circulatory Design
At first glance, the shrimp circulatory system seems rather primitive compared to a human. But the open design actually has some significant advantages:
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Nutrients, oxygen, and carbon dioxide can diffuse directly between tissues and hemolymph without having to cross blood vessel walls. This allows for more efficient transport kinetics.
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Immune cells and proteins within the hemolymph have direct access to tissues and can quickly mobilize against pathogens.
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Development and maintenance of blood vessels is avoided, which is energetically favorable.
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The system is adapted for aquatic life. The open design reduces hydrostatic pressures compared to closed vertebrate circulatory systems.
So while it may seem simple, the shrimp’s circulatory anatomy is well tuned for its way of life as a small marine invertebrate.
