Exocrine glands

B i.e. Sebaceous glands

C i.e. Sebaceous gland 

The lumen of sebaceous gland is filled with secretory cells undergoing cytolysis (holocrine secretion)Q, a process where by the cells degenerate to become the oily secretory product of the gland called sebum. The duct is lined with stratified squamous epitheliumQ that has continuity with the external root sheath of hair follicle.

Ans. is ‘d’ i.e., Nipple is supplied by 6^th intercostal nerve

Mammary gland

• Breast (mammary gland) is a modified sweat gland present in the superficial fascia of pectoral region.
• Vertically it extend from 2″ to 6′ ribs at midclavicular line and horizonal extent is from sternal margin to midaxillary line at the level of 4^th rib.
• Arterial supply of breast

Arterial supply of breast includes ‑

1. Perforating branches of internal mammary artery in II^“,^Hird, 1 v^.-“h intercostal spaces.
2. Thoracoacromial, lateral thoracic and superior thoracic branches of axillary.
3. Mammary branches, from rd, ^3rd and 4′^h posterior intercostal arteries.

Venous Drainage

• There is an anastomotic circle of veins around the base of nipple-the circulus venosus of Haller.
• Veins from this and from the glandular tissue radiate to the circumference of the gland and drain into axillary, internal mammary and posterior intercostal veins.

Nerve supply

• Sensory and sympathetic innervation is via anterior and lateral cutaneous branches of 4^th,5th and 6^th intercostal nerves.
• Nipple is mainly innervated by the 4^th intercostal nerve.

• Sebaceous gland is a  holocrine gland since the discharged secretion contains entire secreting cells.
• Sweat glands are of two types: Eccrine (merocrine) is more common in occurence as compared to apocrine variety.
• Breast (mammary gland) is modified sweat gland of apocrine variety.
• Another example for similar type is ceruminous (wax) gland in the ear.
• Pancreas is a mixed (exocrine & endocrine) gland.
• Exocrine secretory units are usually merocrine type.

Mammary gland is a modified sweat of apocrine variety.

• Parotid gland is predominantly a serous gland & sublingual gland is mucous.
• Submandibular gland is mixed type with a cap of serous gland appearing on mucus (serous demilune) in histological preparations.

A – oral sebaceous (Fordyce) gland

B – duct of oral sebaceous gland

• This is a section through a Fordyce spot (A).
• These glands are simple alveolar and have a holocrine mode of secretion.
• Note their similarity to the sebaceous glands associated with hair follicles.
• The cells arise in the base of the gland and begin to produce an oily product – sebum.
• The accumulation of sebum eventually kills the cell and it is secreted as a sac of oil through the duct (B).