Slide Set 2: The Mammary Gland Flashcards
The mammary gland is composed of
☛ Modified sweat gland
☛ Exocrine gland
☛ Accessory gland to the reproductive system
What are the major components of the mammary gland iin order:
- secretory system
- ductular system
- teats
The udder has a complex structure consisting of the following:
- The mammary gland (s) components
- A supportive system
- Blood, nerve, and lymph systems
How much does the udder weigh?
10-25 kg (empty)
How many glands does the udder have? and what is the structure like? (4)
☛ Four separate simple glands (quarters)
☛ Each gland has one teat & one opening
☛ Right & left halves are entirely separate
☛ Rear quarters are bigger than forequarters
Which quarter is bigger in the udder?
Rear quarters are bigger than forequarters
How is the udder protected?
Skin (10-20% of the empty udder) provides protection but little support
How is the udder attached to skin? How is the udder attached to the abdominal wall?
to skin by fine connective tissue
to abdominal wall by coarse connective tissue
What are the two major groups of ligaments of udder?
Median Suspensory Ligaments (MSL)
Lateral Suspensory Ligaments (LSL)
Where is median suspensory ligament located? What is the structure like?
- Arise from the midline of the abdomen and extend between the udder halves
- Divide the udder into two halves (left & right)
The median suspensory ligament consists of:
Elastic and fibrous connective tissue
What are the functions of the median suspensory ligament?
☛ Provide the primary support for the udder
☛ Provide elasticity needed by the udder to expand as
it fills with milk
☛ Shock absorption
Where is lateral suspensory ligament located? What is the structure like?
- Arise from the tendons around the pubic bone
* Extend along both sides of the udder
The lateral suspensory ligament consists of:
Mostly collagen connective tissue (non-elastic)
What are the functions of the lateral suspensory ligament?
Provide support to the interior of the udder
How many mammary glands does Doe’s udder has and what are the key characteristics? (deer)
- Two mammary glands drained by 2 teats
- Size varies considerably
- Teats are wide at the base and protrude like a funnel from the udder
- Teats are covered with fine hair Supernumerary teats are common
How many mammary glands does Ewe’s udder has and what are the key characteristics? (sheep)
- Two mammary glands drained by 2 teats
- Teats and udder are smaller than in goats
- Gland cisterns are irregular & small
- Teats are covered with fine hair
- Supernumerary teats are common
TRUE/FALSE
Gland cisterns of the Ewe’s udder are regular & big
FALSE
Gland cisterns are irregular & small
How many mammary glands does Sow’s udder has and what are the key characteristics? (pig)
- 3-10 pairs of glands (average 6-7 pairs)
- arranged in two parallel row in either side of the ventral median line.
- There are two openings in each teat and each opening is connected to a separate duct and glandular system.
- Teats in front produce milk than the ones at the back
- Supernumerary teats and inverted nipples are common
How many mammary glands does Mare’s udder has and what are the key characteristics? (horse)
- Two mammary glands each with 2 streak canals (4 glands)
- Teats are flat and broad with blunted tips
- Teats and udder are covered with fine hair and dark pigments
- Sweat and sebaceous glands are present
What are the 4 major components of the women mammary gland?
1- Lobes
2- milk ducts
3- fat pad
4- connective tissue
How many lobes does human mammary gland have? What are their some key characteristics?
- There are 15-20 lobes/breast
- Lobes are separated by connective tissue
- Each lobe is drained by its own lactiferous duct leading directly to the nipples
- Number and size of lobes varies between women and breasts
- There are 6-10 large collecting ducts
- Ducts expand slightly beneath the nipple to form sinuses (ampules)
Where does milk stay before it gets ejected?
ampulla
What is areola what are its functions?
– Pigmented skin in the center of the breast
– Contains sweat and sebaceous glands
– Contains nerve endings (send suckling signals to the brain)
What is nipple what are its functions?
– Terminal point for ducts (lactiferous duct)
– Surrounded by the areola
– During pregnancy, the color becomes darker because of increased pigmentation of the areola and the nipple
The core of the nipple is composed of _________
dense connective tissue &elastic fibers smooth muscle cells (circular & longitudinal)
The wrinkling of the skin on the nipple results from _________
the attachments of the elastic fibers
The contraction of these muscle fibers is responsible for ______ of the nipple.
erection
Most of the _________ located around the lactiferous ducts open onto the surface or sides of the nipple open onto the surface.
sebaceous glands
Compare the structure of lactating breast and inactive breast
- the main difference is the size of the lobule
- in late pregnancy the size of the breast increases.
- the weight of the breast is 150-200g (non lactating)
- in lactating female the weight of the breast is 500g
- if you make a cross section of the lobule you find a group of
What are the components of the mammary tissue? How are they separated?
Lactating
- Parenchyma (lobuloalveolar tissue) —> ductular and secretory system
Non-lactating - Stroma consists of •Connective tissue • Adipose tissue • Nerve & blood tissue
What is the function of the connective tissue of mammary gland?
Support the ductular & secretory tissues
What is the composition of a desirable connective tissue?
- Minimum connective tissue
- Maximum secretory & ductular tissue
The mammary ductular system starts at the ______ & ends at the ______
alveoli
streak canal
What is the order of the mammary ductular system?
terminal ductule –> mammary duct –> gland cistern –> teat cistern
What is the largest structure of the mammary gland?
Lobule
The lobule is composed of bunch of alveolar cells. Where does the milk go from the lobule after it is secreted?
they empty the milk into the alveolar duct tube then join each other to form the mammary duct
Does the milk composition change once the milk is secreted?
No change in milk occurs once it moves into the duct.
Where is the milk stored in between milking? Give examples from mammals
A- Large reservoirs in ruminants (cisterns)
B- Small reservoirs in rats and guinea pigs
C- No reservoirs in rabbits and humans
Cisterns may hold up to 1⁄2 of the milk in the gland
In B& C, most of the milk produced is located in the lobualveolar tissue