Egg Formation in the Oviduct

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Questions and Answers

What role do chalazae play in the egg?

They help the egg rotate in the oviduct.

They provide nutrients to the yolk.

They keep the yolk centered in the egg. (correct)

They strengthen the shell of the egg.

What primarily generates the various layers of albumen as the egg develops?

The rotation of the developing egg and water addition. (correct)

The size of the yolk.

The type of albumen produced in the magnum.

The addition of calcium carbonate.

What happens to thick white post-laying?

It retains its viscous composition.

It increases in volume significantly.

It remains unchanged in quality.

It gradually loses viscosity and volume. (correct)

How long does the egg remain in the isthmus?

About 75 minutes. Signup and view all the answers

What is the role of the mucin in the dense white of the egg?

To hold the thick white together. Signup and view all the answers

What indicates the age or freshness of an egg after laying?

The increase in thin white. Signup and view all the answers

What are the shell membranes made of?

Protein fibers. Signup and view all the answers

What happens to the thin white as the egg develops?

It increases in volume and becomes more watery. Signup and view all the answers

What forms at the large end of the egg when the two membranes separate?

Air cell Signup and view all the answers

How does the size of the air cell change as the egg ages?

Increases in diameter and depth Signup and view all the answers

What is the function of the cuticle on the eggshell?

Resists bacterial invasion Signup and view all the answers

What effect do high surrounding temperatures and low humidity have on eggs?

Increase air cell size Signup and view all the answers

What happens to the cuticle after the egg is laid?

Dries and seals pores Signup and view all the answers

Which pigment is responsible for the brown color in eggshells?

Porphyrin Signup and view all the answers

What is the primary role of the vagina in the egg-laying process?

Expulsion of the egg Signup and view all the answers

What is the typical orientation of the egg when it is expelled from the hen?

Large end first Signup and view all the answers

What can affect the effectiveness of the cuticle?

Shell cleaning processes Signup and view all the answers

How long can an egg be held in the vagina during egg production?

A few hours Signup and view all the answers

Study Notes

Egg Formation in the Oviduct

Egg formation involves several stages within the oviduct
The process begins in the infundibulum
The yolk, ovulated by the ovary, is captured by the infundibulum ( funnel-shaped part of the oviduct)
Fertilization ( if it occurs) takes place here.
The ovum, now called an egg, transitions to the magnum

Magnum

Albumen (egg white): One type of albumen is initially produced in the magnum.
Layers of albumen: Water addition and egg rotation lead to different layers of albumen (e.g., liquid inner white, dense white)
Dense white (albumen): Makes up the majority of the albumen; mucin holds it together.
Thick vs. Thin White: Thick white is initially more abundant in the magnum, but water addition and mucin breakdown in the oviduct result in a higher proportion of thin white when the egg is laid.
Egg quality changes: After laying, thick white loses viscosity, volume decreases, while thin white becomes more watery and increases. This change is affected by temperature, humidity, age, and illness.

Isthmus

The isthmus: A relatively short section (10 cm) of the oviduct.
Inner and outer shell membranes: In the isthmus, the final egg shape of the shell membranes is formed, starting with the inner membrane.
Outer shell membrane: Three times thicker than the inner membrane.
Air cell formation: Inner and outer membranes separate at the large end forming the air cell
Air cell Purpose: The air cell gradually increases in size as moisture evaporates through the shell pores as the egg ages.

Shell Gland/Uterus

Shell Formation: The egg shell is formed in the shell gland/uterus.
Shell Color: Color is determined genetically.
Shell Pigment: Porphyrin is the brown pigment in eggshells
Cuticle: A protective layer on the outside of the shell, made mainly of organic material.
Cuticle's Role: Lubricates laying, seals pores after laying to inhibit moisture loss and bacterial entry.
Cuticle damage: Washing and sanding eggs damages the cuticle.
Solution: Mineral oil applied to the shell surface helps slow moisture loss after processing for better quality.

Vagina

Vagina role: The final section of the oviduct, approximately 12 cm long, expels the egg.
Egg Positioning: Usually laid large end first. Rotation before laying aids in this.
Disturbances effect: If the hen experiences disturbance, the egg can be laid small end first.

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Description

Explore the intricate process of egg formation within the oviduct, starting from the infundibulum to the magnum. Learn how fertilization occurs, the development of albumen layers, and changes in egg quality after laying. This quiz covers the essential stages of avian reproduction.