Mammary Gland and Lactation- Lecture 19

Question 1

Blockage of milk letdown

Answer 1

Unusual stimuli or pain stimulus is sent to pituitary gland. Adrenaline from nerve endings overcome letdown hormone action.

Question 2

Milk Synthesis

Answer 2

Lactogenesis. Milk is produced by specialized epithelial cells and secreted into the lumen of alveolus.

Question 3

Involution

Answer 3

Atrophy of secretory cells induced by cessation of suckling, and decreased prolactin and GH.

Question 3

Puberty

Answer 3

Further duct and alveolar development- allometric growth. Progetersone stimulates alveoli growth. Estrogen stimulates duct system growth. Growth hormone also contributes to MG development.

Question 4

Failure of passive transfer

Answer 4

Inadequate supple from damn. Failure to suckle. Failure to absorb into bloodstream- GI colonization by microbes.

Question 5

Secretion and continued production of milk

Answer 5

Galactopoiesis. Prolactin and growth hormone stimulate galactopoiesis. Suckling stimulates ocytocin release- myoepithelial cell contraction (milk let down).

Question 5

Involution

Answer 5

Gradual regression of mammary gland following a lactation. Decrease in prolactin and GH (signals apoptosis of cells). Cessation of suckling or milking- decreases stimulates for production.

Question 7

Embryology

Answer 7

Modified sweat glands. Mammary ridges. Primary and secondary buds.

Question 8

Mammary gland function

Answer 8

Mammary gland plays a key role in allowing the fetus to survive outside the uterus. Antibody transfer and nutrition.

Question 9

Ducts per teat

Answer 9

Cow: 1 per teat. Horse: 2-3 per teat. Dog: 5-6 per teat. Primates: 8-10 per teat.

Question 10

Galactopoiesis

Answer 10

Secretion and continued production of milk

Question 11

Factors affecting colostrum quality

Answer 11

Age of damn (older=better). Number of lactations. Vaccine status. Health of dam. Volume of colostrum (less=better).

Question 12

When does lactation peak?

Answer 12

3-8 weeks following its onset. Then declines steadily.

Question 13

Higher the frequency of milk removal…

Answer 13

Higher the production. Removal of milk from mammary gland causes less pressure and less feedback of inhibitor lactation (FIL).

Question 14

Prepartum immunoglobulin transfer

Answer 14

Dog/cats has 5-10% this, but mostly done though colostrum after birth. For primates 90% of immunoglobulin transfer is done before birth. For all other species, 100% is done via colostrum.

Question 16

Lactogenesis

Answer 16

Production of milk

Question 17

Four stage of lactation

Answer 17

Mammogenesis. Lactogenesis. Galactopoiesis. Involution.

Question 18

Mammogenesis

Answer 18

Development of mammary gland

Question 19

Colostrum

Answer 19

First milk from dam. Provides passive transfer of immunoglobulins (IgG). Protection against pathogens in the first month of life. Neonatal immune system not mature.

Question 20

Polythelia

Answer 20

Supernumerary nipples. Fairly common (2-6% female, 1-3% male).

Question 21

Pregnancy

Answer 21

Terminal alveoli develop under influence of prolactin, adrenal corticosteroids, and placental lactogen. Lactogenesis is tiggered by a decrease in progesterone and increase in prolactin.