Lactation Flashcards
what is the mammary gland
milk secreting structure
- teat
- duct system
- lobes
what is the udder
complex organ made up of a series of systems
what are the different systems in the udder
supportive system
secretory system
duct system
blood, lymph and nerve systems
describe the udder of a cow
- two separate halves
- 4 separate mammary glands
- it is an exocrine gland
When is the greatest growth of the udder and when does the growing stop
- greatest growth between 1st and 2nd lactation
2. stops growing after 5 years of age
describe 4 things about the mammary gland
- specialized skin glands
- produce colostrum
- present in males and females
- number and appearance differs among species
what are the 2 parts of the mammary gland support system and describe them
- Lateral Suspensory Ligament (LSL)
- extends along both sides of udder to midline
- connects to MSL - Medial Suspensory Ligament ( MSL)
- provides most support and elasticity
- creates 2 distinct halves between left and right
in what species do two glands drain to 1 teat
sows (10-14 teats)
mares (2 teats)
queens (10 teats)
bitches (8-12 teats)
what is a function of a teat besides excretion of milk
main barrier against infection
how many glands per teat in cows and ewes
1 gland per teat
what are the 6 parts of a mammary gland
- streak canal
- teat cistern
- gland cistern
- duct system
- lobule
- alveoli
what is the streak canal
first part of the teat
- milk passes before expulsion
- keratin plug will form to prevent entrance of bacteria
- surrounded by teat sphincter muscle to prevent leaking
what is the teat cistern
- storage of milk prior to suckling or milking
2. holds 100-400 mL of milk
what is the gland cistern
common pooling area for milk from duct system
what is the duct system
- TRANSPORTS milk from lobule to gland cistern
- consists of 1st and 2nd degree ducts
- non secretory
what is the lobule
each lobule contains 150 to 220 alveoli
This is the place where milk is actually produces
what are alveoli and what are their 3 functions
they are the producers of milk
functions
- remove nutrients
- transform into milk
- discharges into duct system
What makes up the alveolus
- lumen: opening of alveolus that collects milk
- epithelial cells: secreting cells of alveolus
- duct: transports milk from the alveolus to the gland cistern
- myoepithelium: muscle cells that contract in response to oxytocin
- arterioles and venuoles: provide blood flow
- brings substrates for milk production
how many liters of blood must flow to the udder to make 1 liter of milk
500L
describe mammary gland before birth
very immature gland
duct system is initiated
non functional teats present
describe mammary gland at birth
glands and teats are present
streak canal
teat and gland cistern
rudimentary collecting ducts
describe mammary gland from birth to puberty
- immature gland grows in size and function
- grow at similar rate to rest of body
- growth initiated by growth hormones release from pituitary gland
describe mammary gland from puberty to pregnancy
- glands grow with each additional estrous cycle
- sex hormones (progesterone and estrogen) produces by ovary simulate growth
- growth is more rapid than the rest of the body
mammary gland during pregnacy
- progesterone produced by placenta stimulates lobular development
- preparation for nursing by young