12 Questions
What is the composition of the outer thick layer of the wall?
Numerous small blood-lacunae
Where does the labyrinth lie in relation to the end sac?
On the outer side of the end sac
How does the labyrinth open into the bladder?
By a single aperture
Where is the bladder located in relation to the end sac?
On the outer side of the end sac
What do the tubules of the labyrinth in the glandular plexus consist of?
Large excretory epithelial cells with granular cytoplasm
What is the function of the antennar glands mentioned in the text?
Extract nitrogenous waste products and excess water from blood
What does plasma transport to the desired organs?
Oxygen, carbon dioxide, and food
What happens if an appendage is forcibly removed?
Blood clots immediately
Which part of the antennary gland is as big as a pea-seed or gram seed?
The end sac
How many layers make up the wall of the end sac of an antennary gland?
Two layers
Where is the antennary gland located in relation to the antenna in a prawn?
Within the coxal segment of each antenna
What is the size of each antennary gland in a prawn?
As big as a pea-seed or gram seed
Study Notes
Blood Circulation
- Plasma transports food, oxygen, carbon dioxide, and waste materials to organs
- Blood has remarkable clotting properties, forming clots quickly to minimize blood loss
- Course of circulation: heart forces blood through arteries to all parts of the body, then to gills and blood sinuses before returning to the heart
Excretory System
- Consists of antennary glands, lateral ducts, renal sac, and integument
Antennary Glands
- One gland in each antenna's coxal segment
- Opaque white gland with three parts: end sac, labyrinth, and bladder
- End sac: bean-shaped, smallest part with blood-lacuna in its cavity
- Labyrinth: larger part with coiled excretory tubules, lined with excretory epithelial cells
- Bladder: largest part, thin-walled sac with excretory duct (or ureter) opening to the outside
Lateral Ducts
- Narrow ducts running posteriorly from each bladder to renal sac
- Connected by a transverse connective in front of the brain
Renal Sac
- Large, thin-walled sac above the cardiac stomach, extending to gonads
- Wall made of a single layer of flattened excretory epithelial cells
Integument
- Non-living chitinous covering cast off at each moult, expelling nitrogenous products
- Plays a role in excretion
Physiology of Excretion
- Antennary glands have a dual function: excretion of nitrogenous waste products and osmoregulation (excess water removal)
- Function similar to vertebrate kidneys
Test your knowledge on the human circulatory system with this quiz. Learn about the transportation of food, oxygen, carbon dioxide, and waste materials in the blood, as well as the clotting properties of blood. Understand the course of circulation in the body through the heart and arteries.
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