All mammals have mammary glands and produce milk
Discuss the features of mammary glands that all mammals have in common, and describe the differences in the anatomical structure of mammary glands in the three different groups of mammals (monotremes, marsupials, and eutherians).
Answer: In all mammals, mammary glands consist of exocrine glands, which secrete milk and myoepithelial cells that have control over the secretions. Mammary glands are similar to sebaceous glands in that they are associated with hair follicles. Milk is released from exocrine glands; milk's composition includes macromolecules and fluids, and prolactin controls milk production.
Mammary glands of monotremes consist of convoluted tubes that lie under the skin of the female on the ventral side. Monotremes have no nipples, so the milk oozes through the ducts onto the female's fur and the pups lap up the milk. Marsupials have mammary glands with teats. A newborn marsupial takes the teat into its mouth; the teat enlarges in its mouth and keeps the newborn in position. The mammary glands of eutherian mammals consist of globes grouped into alveoli and the alveoli have ducts, which lead to an external teat. Whenever young eutherian mammals are hungry, they locate the teat, suck the milk, and release the teat upon satiation or when the mom walks away.
You might also like to view...
Which is the neurotransmitter that causes the release of calcium ions and initiates the steps of skeletal muscle fiber contraction?
A. Acetylcholine B. Acetylcholinesterase C. Norepinephrine D. Serotonin
Moving the parts of a joint farther apart, so the angle between them increases, is called
A. adduction. B. eversion. C. extension. D. abduction. E. flexion.
A female has a blood test. One mL of her blood is drawn, sspun in a centrifuge, and the plasma volume is measured and found to be 0.6 mL
Two months later the same patient returns to the doctor and, after doing another blood test, the doctor tells the patient that she has become anemic compared to her previous visit. Which of the following is most likely to be the woman's hematocrit on the second visit? A. 35% B. 50% C. 70% D. 100% E. 0.6 mL
An injury that results in complete functional loss of the ulnar nerve will affect which of the following muscles?
A) Abductor digiti minimi B) Extensor indicis C) Abductor pollicis brevis D) Brachioradialis E) Flexor carpi radialis