Cytotrophoblast

Cytotrophoblast

it is the inner layer of trophoblast . It is situated into interior of  the syncytiotrophoblast and external to the wall of the blastocyst in a developing embryo.

It is the trophoblastic stem cells which has  important role in implantation. It is not establishes nutritional supply between mother to fetus

It can differentiated into other types of cells. This tissue  is formed by individual cells.

This layer does not produce hormones

Formation and fate of trophoblast

Formation and fate of trophoblast

As cleavage proceeds the ovum comes to have 16 cells. this is known as morula.
The morula consists of an inner cell mass that is completely surrounded by an outer layer of cells. The cells of the outer layer later give rise to trophoblast

Fate :
It divides into two layers outer and inner. The inner one is cellular and called as cytotrophoblast. The outer one having no cell boundary is termed syncytotrophoblast . these two together with primary mesoderm constitute chorion .

Sign of mature fetus

Sign of mature fetus

• Dry, loose, peeling skin,smooth, pink and covered with vernix caseosa
• Overgrown nails.
• Large amount of hair on the head.
• Visible creases on palms and soles of feet.
• Small amount of fat on the body.
• Green, brown, or yellow coloring of skin from baby passing stool in the womb.
• More alert and "wide-eyed", moves and cries vigorously when born
• Creases on baby’s palm and sole
• Lanagu absent from most situations

Histology of lacrimal gland with difference between parotid and lacrimal gland

Lacrimal gland

It is situated external to the eye located in the superolateral aspect of the orbit .

It is an exocrine gland compound tubuloalveolar glands. It is divided into many lobule by connective tissue . each lobule contain many acini .  Each acinus contain large lumen and  a grape-like mass of lacrimal gland cells with their apices pointed to a central lumen. Each acinus is composed of column-shaped cells of the serous type, resembling the parotid acinar cells. These cells show lightly stained secretory granules, and a basal lamina separates them from the surrounding connective tissue. well-developed myoepithelial cells surround the secretory portions of the lacrimal gland.

Ducts: approximately 12 ducts drain from the lacrimal gland in the reflection of conjunctiva . It contains intralobular and interlobular duct but no striated duct.  Parotid gland has striated duct.

Drainage of tear:

Conjunctival sac

Lacrimal puncta

Lacrimal canaliculus

Lacrimal sac

Nasolacrimal duct

Inferior meatus of the nasal cavity

Secretion : it producing a lysozyme rich serous fluid with an alkaline pH. It contain an enzyme that hydrolyzes the cell walls of certain species of bacteria, facilitating their destruction.

It protect corneal epithelium and contain antibacterial and UV protective agents .

 Blood supply

The lacrimal artery derived from the ophthalmic artery supplies the lacrimal gland. Venous blood returns via the superior ophthalmic vein.

Lymphatic drainage

The glands drain into the superficial parotid lymph nodes

Nerve supply

The lacrimal nerve, derived from the ophthalmic nerve, supplies the sensory component of the lacrimal gland.

The greater petrosal nerve, derived from the facial nerve, supplies the parasympathetic autonomic component of the lacrimal gland.

The sympathetic postganglionic fibers originate from the superior cervical ganglion.

Clinical anatomy : Inflammation of the lacrimal glands is called dacryoadenitis

Retromammary space

•      Retromammary space is a loose areolar tissue  that separates the breast from the

     pectoralis major muscle.

•      The retromammary space is often the site of breast implantation due to its location away from key nerves and structures that support the breast.

•      Clinical importance: Cancer cells spread through retromammary space.

Retromammary space

•      Retromammary space is a loose areolar tissue  that separates the breast from the

     pectoralis major muscle.

•      The retromammary space is often the site of breast implantation due to its location away from key nerves and structures that support the breast.

•      Clinical importance: Cancer cells spread through retromammary space. 

Identify retromammary space

1. Q. The retromammary space:
   lies deep to pectoralis major muscle
2. Lies superficial to deep layer of superficial fascia
3. Lies between  deep layer of superficial fascia to pectoral fascia Ans
4. Lies between  deep layer of superficial fascia to glandular tissue of breast
5. None of above