AnS 214 SI Session 26

Sunday, 11/15, 8pm

A. Evolution of the mammary gland

1) What are the two defining characteristics of mammals?

2) The mammary gland is a gland of ______.

3) List three reasons for why the above statement is true:

· 

4) Describe the mammary glands of the duck-billed platypus, and how they differ from most mammalian species.

5) The development of what structure marked the evolution of marsupials?

Why was this structure important?

6) The most advanced mammalian order is called what?

What differentiates them from marsupials?

B. Mammary variation between species

1) What are the three body regions where mammary glands are found?

2) For each of the species below, list the number and location of teats and the number of

Species / # and location of teats / # of openings/teat
Cow
Ewe
Mare
Queen
Bitch
Kangaroo
Mouse
Opossum
Orca
Human

C. Development of the mammary gland

1) After the initial thickening of the ectodermal tissue during the ______and ______formation phases, teat formation is begun with the invagination of the ______tissue layer, and the pushing out of the ______layer. This downward progression forms the ______. During this time, the opening to this structure is sealed with ______.

2) What elements make up the non-secretory support for the mammary gland?

3) What two structural features of the mammary gland are well formed at birth?

What components are missing?

4) What is the difference between male and female mammary glands at birth?

6) Name the main hormones responsible for the formation of each of the following in rodents. Name the life stage at which these would occur.

Structural development / Hormone(s) Involved / Life stage
Primary ducts and fat pad
Ductal development into fat pad
Extensive duct growth and branching
Development of lobules and alveoli; attainment of secretory capacity

7) In the cow, what structure provides the primary support to the udder?

8) T/F In the cow, introduction of dye into one teat will result in its permeation of all four quarters of the udder.

9) What two body systems are vital to the support of lactation?

C. Mammary secretion and ejection

1) Fill in the blanks of the alveolus at right.

2) Milk is produced in the ______cells, stored in the alveolar ______, and ejected via the contractions of ______cells.

3) Trace the path of milk from the secretory epithelial cells to the outside of the female body.

4) The four characteristics of a fully differentiated alveolar secretory cell are:

1.

2.

3.

4.

5) Overabundance of what two tissue types in the mammary gland can greatly decrease milk yield in lactating females?

What conditions can cause the above to form?

6) The main hormone that stimulates milk secretion is ______, from the ______pituitary. The main hormone that stimulates ejection is ______, from the ______pituitary.

7) Milk let down involves a ______reflex path. Initial stimulation travels to the ______from the inguinal nerves, and causes the posterior pituitary to release ______, resulting in the contraction of ______cells. ______from the ______pituitary causes the alveolar secretory cells to produce milk.

8) What events can interrupt the above letdown cascade?