Changes

== Introduction  ==

== Introduction  ==

== Structure  ==

== Structure  ==

The '''mamma (pleural = mammae) ''' is the glandular structure associated with a teat. The '''udder''' is a term designating all the mammae in the ruminant and the mare (sometimes used for the sow). The '''lobes''' are the internal compartments of the mamma, separated by adipose tissue. The lobes are divided into '''lobules''', consisting of connective tissue containing '''alveoli''', which are clusters of milk secreting cells. The '''lactiferous ducts''' are large ducts conveying milk from the alveoli to the milk sinus. The openings of the lactiferous ducts convey milk formed in the alveolus to the gland sinus.  

The '''mamma (pleural = mammae) ''' is the glandular structure associated with a '''papilla '''(teat) and may contain one or more duct systems. The '''udder''' is a term designating all the mammae in the ruminant and the mare (sometimes also used for the sow). The '''lobes''' are the internal compartments of the mamma, separated by adipose tissue. The lobes are divided into '''lobules''', consisting of connective tissue containing '''alveoli''', which are clusters of milk secreting cells. The '''lactiferous ducts''' are large ducts conveying milk from the alveoli to the '''lactiferous sinus'''. The openings of the lactiferous ducts convey milk formed in the alveolus to the gland sinus.  

The '''milk or lactiferous sinus''' is the milk storage cavity within the teat and glandular body. The '''gland sinus''' is part of the milk sinus within the glandular body and the '''teat sinus''' is part of the milk sinus within the teat.  

The '''lactiferous sinus''' (milk sinus) is the milk storage cavity within the teat and glandular body. The '''gland sinus''' is part of the milk sinus within the glandular body and the '''teat sinus''' is part of the milk sinus within the teat.  

The '''teat''' is the projecting part of the mammary gland containing part of the milk sinus. The '''teat canal''' is the canal leading from the teat sinus to the teat opening. The '''teat opening''' is the opening of the teat canal and the exit point for milk or entrance point for bacteria into the mammae. The '''sphincter''' consists of muscular fibres surrounding the teat opening that prevent milk flow except during suckling or milking.  

The '''teat''' is the projecting part of the mammary gland containing part of the milk sinus. The '''papillary duct '''(teat canal) is the canal leading from the teat sinus to the teat opening and may be single or multiple. The '''ostium '''(teat opening) is the opening of the papillary duct and the exit point for milk or entrance point for bacteria. The '''sphincter''' consists of muscular fibres surrounding the teat opening that prevent milk flow except during suckling or milking.  

=== Suspensory Apparatus  ===

=== Suspensory Apparatus  ===

The suspensory apparatus is organised into the lateral and medial laminae, which suspend the mammary gland from the ventral aspect of the trunk by their attachment to the pubic symphysis. The '''lateral lamina''' consists of collagen fibres from the fascia of the pubic symphysis and the edge of the superficial inguinal ring. The '''medial lamina''' consists of elastic fibres from the tunica flava ventral to the pubic symphysis The '''intermammary groove''' divides the left and right rows of mammary complexes.  

In species with large udders, especially in dairy cattle, there is a  suspensory apparatus, which is organised into the lateral and medial laminae suspending the mammary gland from the ventral aspect of the trunk by their attachment to the pubic symphysis. The '''lateral lamina''' consists of collagen fibres from the fascia of the pubic symphysis and the edge of the superficial inguinal ring. The '''medial lamina''' consists of elastic fibres from the tunica flava ventral to the pubic symphysis The '''intermammary groove''' divides the left and right rows of mammae.  

== Blood Supply  ==

== Blood Supply  ==

=== Arteries  ===

=== Arteries  ===

In species with '''inguinal mammary glands''' (cow, ewe, goat, mare), the main blood supply is from the '''external pudendal artery'''. This arises indirectly from the external iliac artery via the femoral artery. The external pudendal artery passes through the inguinal canal. In species which also have '''thoracic mammary glands''' (bitch, queen, sow) blood supply is from the '''internal thoracic artery''' and its branches - cranial and cranial superficial epigastric arteries.  

The main blood supply to the inguinal mammary glands is from the '''external pudendal artery'''. This arises indirectly from the external iliac artery via the deep femoral artery. The external pudendal artery passes through the inguinal canal. In species which also have '''thoracic and abdominal mammary glands''' (bitch, queen, sow) additional blood supply is derived from the '''internal thoracic artery''' and its branches - cranial superficial epigastric arteries as well as from '''lateral thoracic''' and '''intercostal arteries'''.  

=== Veins  ===

=== Veins  ===

'''Thoracic mammary complexes''' drain into '''cranial superficial epigastric veins''' and open into the '''cranial epigastric vein'''. It drains into the '''internal thoracic vein'''.  

In most species'''thoracic and cranial abdominal mammary glands '''drain via '''cranial superficial epigastric veins''' into the '''internal thoracic vein'''. '''Caudal abdominal and inguinal mammary glands '''drain via '''caudal superficial epigastric veins''' into the '''external pudendal vein'''.  

'''Abdominal and inguinal mammary complexes''' drain into '''caudal superficial epigastric veins''' and open into the '''external pudendal vein'''.  

In cattle a venous ring is formed between the base of the udder and the abdominal wall. During the first pregnancy, an anastamosis develops between cranial and caudal superficial epigastric veins forming the '''subcutaneous abdominal vein''' (milk vein). As a result some drainage from venous ring passes in a cranial direction via this vessel, which then drains deeply through the abdominal wall (milk well) into the internal thoracic vein. Other drainage passes to the external pudendal veins or to perineal veins.<br>

== Innervation  ==

== Innervation  ==

There is '''sympathetic''' innervation to the blood vessels and teat sphincter smooth muscle via the '''genitofemoral nerve''' and '''somatic''' innervation via the ventral rami of the spinal nerves. In the cow, the ventral branches of L1 and L2 ('''iliohypogastric and ilioinguinal''') supply the skin of the cranial forequarters. Mammary branches of the '''pudendal nerve''' supply the caudal aspect of the udder (hindquarters). Mammary glands are, however, mainly under the influence of endocrine hormones.  

Somatic innervation is via the ventral rami of the spinal nerves. In the cow, the ventral branches of L1 and L2 ('''iliohypogastric and ilioinguinal''') supply the skin of the cranial glands. Mammary branches of the '''pudendal nerve''' supply the caudal aspect of the udder. There is sympathetic innervation to the blood vessels and teat sphincter smooth muscle. Mammary glands also have major influence from endocrine hormones.  

== Lymphatics  ==

== Lymphatics  ==

The '''inguinal mammary glands''' contain a superficial inguinal lymph node and the '''thoracic mammary glands''' contain an axillary lymph node.  

The more caudal mammary glands drain to the&nbsp; '''superficial inguinal lymph node''' and the more cranial mammary glands to the axillary or sternal lymph nodes.  

=== Lymphatic drainage in the cow  ===

=== Lymphatic drainage in the cow  ===

The '''afferent lymphatic ducts''' pass dorsocaudally to reach the mammary lymph nodes (superficial inguinal). The '''mammary (superficial inguinal) lymph nodes''' include two nodes at the dorsocaudal side of the udder, usually a palpable large, kidney-shaped node between the caudal side of the udder base and the thigh. The '''efferent lymphatic ducts''' pass into the abdomen through the inguinal canal to empty into the deep inguinal node. The '''deep inguinal lymph node''' is small and located in the dorsocaudal udder. It is too deep to be palpated.

The '''afferent lymphatic ducts''' pass dorsocaudally to reach the '''superficial inguinal''' (mammary) lymph nodes at the dorsocaudal side of the udder. These are&nbsp; usually palpable large, kidney-shaped nodes between the caudal side of the udder base and the thigh. The '''efferent lymphatic ducts''' pass into the abdomen through the inguinal canal to empty into the deep inguinal node.&nbsp;

== Histology  ==

== Histology  ==

! '''Cat'''

! '''Cat'''

|-

|-

| '''Number of Mammary Glands'''  

| '''Number of Mammae/teats'''  

| 2  

| 2  

| 2  

| 2  

<br> Click here for more information on the [[Cow Mammary Gland - Anatomy & Physiology|cow]], [[Small Ruminant Mammary Gland - Anatomy & Physiology|small ruminant]], [[Sow Mammary Gland - Anatomy & Physiology|sow]], [[Mare Mammary Gland - Anatomy & Physiology|mare]] and [[Carnivore Mammary Gland - Anatomy & Physiology|carnivore]].  

<br> Click here for more information on the [[Cow Mammary Gland - Anatomy & Physiology|cow]], [[Small Ruminant Mammary Gland - Anatomy & Physiology|small ruminant]], [[Sow Mammary Gland - Anatomy & Physiology|sow]], [[Mare Mammary Gland - Anatomy & Physiology|mare]] and [[Carnivore Mammary Gland - Anatomy & Physiology|carnivore]].  

== Links ==

|flashcards = [[Reproductive System Flashcards - Anatomy & Physiology|Mammary gland flashcards]]

|powerpoints = [[Mammary Gland Histology resource|Histology of the mammary gland]]

|videos = [[Video: Bovine teat and mammary gland potcast|Bovine teat and mammary gland potcast]]<br>[[Video: Mammary gland of the ewe|Mammary gland of the ewe]]

|date=20/03/2011}}

[[Category:Female_Reproduction]] [[Category:Integumentary_System_-_Anatomy_&_Physiology]] [[Category:A&P_Done]] [[Category:David_Hogg_reviewing]]

 

[[Category:Female_Reproduction]] [[Category:Integumentary_System_-_Anatomy_&_Physiology]] [[Category:A&P_Done]] [[Category:David_Hogg_reviewed]]