The udder is composed of glandular tissue which contains milk-produ-cing cells.
It is encased in muscular tissue, which gives cohesion to the body of the udder and protects it against injury from knocks and blows. The glandular tissue contains a very large number (about 2 billion) of tiny bladders called alveoli.
The actual milk-producing cells are located on the inner walls of the alveoli, which occur in groups of between 8 and 120. Capillaries leading from the alveoli converge into progressively larger milk ducts which lead to a cavity above the teat.
The cistern of the udder has an extension reaching down into the teat; this is called the teat cistern. At the end of the teat there is a channel 1 – 1.5 cm long. Between milkings the channel is closed by a sphincter muscle which prevents milk from leaking out and bacteria from entering the udder. The whole udder is laced with blood and lymph vessels. These bring nutrient-rich blood from the heart to the udder, where it is distributed by capillaries surrounding the alveoli.
In this way the milk-producing cells are furnished with the necessary nutrients for the secretion of milk. “Spent” blood is carried away by the capillaries to veins and returned to the heart. The flow of blood through the udder amounts to 90 000 litres a day. It takes between 800 and 900 litres of blood to make one litre of milk.
Reference:
It is encased in muscular tissue, which gives cohesion to the body of the udder and protects it against injury from knocks and blows. The glandular tissue contains a very large number (about 2 billion) of tiny bladders called alveoli.
The actual milk-producing cells are located on the inner walls of the alveoli, which occur in groups of between 8 and 120. Capillaries leading from the alveoli converge into progressively larger milk ducts which lead to a cavity above the teat.
The cistern of the udder has an extension reaching down into the teat; this is called the teat cistern. At the end of the teat there is a channel 1 – 1.5 cm long. Between milkings the channel is closed by a sphincter muscle which prevents milk from leaking out and bacteria from entering the udder. The whole udder is laced with blood and lymph vessels. These bring nutrient-rich blood from the heart to the udder, where it is distributed by capillaries surrounding the alveoli.
In this way the milk-producing cells are furnished with the necessary nutrients for the secretion of milk. “Spent” blood is carried away by the capillaries to veins and returned to the heart. The flow of blood through the udder amounts to 90 000 litres a day. It takes between 800 and 900 litres of blood to make one litre of milk.
Reference:
- Tetra Pak Processing Systems AB S-221 86 Lund, Sweden
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