Embryology/ Histology Flashcards by Lor L

What are the divisions of the Pituitary Gland?

Adenohypophysis
Neurohypophysis

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Fill in the blanks. “ Adenohypophysis ( Anterior pituitary) is divided into ______, ______ & _______.”

Pars distalis (anterior lobe)
Pars tuberalis
Pars intermedia

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Fill in the blanks. “ The neurohypophysis( Posterior pituitary) is divided into _______ & _______.”

Pars nervosa
Infundibulum

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What is the name of the structure that connects the hypophysis with the hypothalamus?

Infundibulum

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What is the name of the structure that surrounds the Infundibulum?

Pars tuberalis

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True or False? The pars distalis of the adenohypophysis accounts for about 75% of the hypophyseal tissue.

TRUE!!

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What does the Pars intermedia represent?

It represents residual lumen of Rathke’s pouch & Contains colloid-filled vesicles surrounded by cells of pars intermedia.

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True or False? The Pars nervosa consists mainly of myelinated axons and supportive cells (pituicytes).

FALSE!!! The Pars nervosa ( of the pituitary gland contains mainly UNMYELINATED axons and supportive cells ( pituicytes).

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What is the name of the supportive cells of the Posterior pituitary gland?

Pituicytes

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What is the name of the structure that surrounds both Pars distalis( A. pituitary ) & Pars nervosa ( P. Pituitary)?

Connective tissue capsule

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What structures are found in the hypothalamic- hypophyseal tract?

It consists of axons extending from the Hypothalamic SUPRAOPTIC c & PARAVENTRICULAR nuclei.

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What are the two main types of cells found in Pars Distalis?

+ Chromophobe cells
+ Chromophil cells

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Fill in the blanks. Chromaphil cells are divided into ________ & ________. “

Acidophils (alpha cells)
Basophils (beta cells)

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Fill in the blanks. “All known hormones of the adenohypophysis are ________.”

Proteins or Glycoproteins

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What types of cells exhibit clear and very light cytoplasm?

Chromophobes

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What types of cells has its cytoplasmic granules stain intensely red ?

Acidophils

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What colour stain is given from the appearance of Pituicytes?

Orange

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What type of cells account for 65% of the cells in the Adenohypophysis?

Acidophils ( Acidophilic cells)

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What type of cells produce Growth hormone/ Somatotropin?

Somatotrophs

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What type of cells secrete Prolactin?

Mammotrophs(or lactotrophs)

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Fill in the blanks. “ Somatotrophs and Mommotrophs are types of ___________ cells.”

Acidophilic ( Acidophils)

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What are the different type of Basophils and what substances do they each produce?

Thyrothrophs producing Thyroid Stimulating Hormone ( TSH)
Gonadotrophs producing FSH & LH.

3.Corticotrophs (adrenocorticolipotrophs) producing Adrenocorticotropichormone(ACTHor corticotropin) & Lipotropin (LPH)

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What type of cells are mostly found in the Pars Intermedia?

Basophilic cells - Corticotrophs

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Lutenizing hormone stimulates the production of testosterone by what cells in males?

Leydig cells

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Which cells has precursors of ACTH and LPH which undergo hydrolysis to produce Melanocyte stimulating hormone (MSH)?

Corticotrophs (Adrenocorticolipotrophs)

During foetal life, what substance is expressed by the Pars intermedia?

Pro-opiomelanocortin (POMC)

Where is Oxytocin produced from?

Paraventricular nucleus

Where is ADH(Vasopressin ) produced from?

Supraoptic nucleus

Fill in the blanks. "Oxytocin and ADH are bound in granules to carrier proteins namely ____________."

Neurophysin I & II

What is the name of the structure that surrounds the Pineal Gland?

Pia Mater

What are the two types of cells found in the Pineal glands?

Pinealocytes & Astrocytes

What is the most prominent secretory product of the Pineal body?

Melatonin

Fill in the blanks. " Secretory activity in the pineal gland is stimulated by ______ and inhibited by ______."

Stimulated by Darkness Inhibited by Light

What is the innervation for the Pineal Body?

The pineal body is innervated by postganglionic sympathetic fibres derived from the superior cervical ganglion.

How is the nuclei described when stained in Atstrocyes & Pinealocyets ?

Astrocytes - Small , dark nuclei Pinealocytes - Light , larger , round nuclei surrounded by broad rim of cytoplasm.

What is considered the structural and functional block of the thyroid gland?

The follicle

What epithelium lines the Thyroid Gland?

Simple cuboidal epithelium

Where is the Thyroid gland located?

It is situated on the lateral sides of the lower part of the larynx and upper part of the trachea.

What is the name given to the secretory product of the Follicular cell in the Thyroid gland?

Colloid

What are the main components found in Colloid?

Thyroglobulin

What are the main components found in Thyroglobulin?

Triiodothyronine (T3) and Tetraiodothyronine (or thyroxine) (T4

Where are C cells normally located ?

They are located basally in the epithelium.

What substance does C-cells ( parafollicular cells) produce?

Calcitonin

What are the two main types of cells found in the Parathyroid glands?

* Chief cells (Principal cells) * Oxyphillic cells

What substance is secreted by chief cells ?

Parathyroid hormone This is not STOMACH!!

What is the function of Parathyroid hormone?

It is of pivotal importance for normal calcium concentrations in the fluids and tissues of the body.

What would happen if the Parathyroid hormone was to be removes completely?

If the parathyroid glands are removed completely, calcium concentrations decrease rapidly, leading to tetany within 2-3 days and eventually death if left untreated.

Where is the Adenohypophysis derived from?

Buccal oral ectoderm

Where is the Neurohypophysis derived from?

Neural ectoderm

When does the Hypothalamus begin to develop?

At week 5

True or False? The thyroid gland develops at week 4 while the parathyroid glands develop at week 5.

TRUE!!

What are the structures which the Diencephalon gives rise to?

Subthalamus Epithalamus Thalamus Hypothalamus

Fill in th blanks. " The diencephalon is derived from ______."

Prosencephalon

The hypothalamus is derived from?

Diencephalon.

What structures do the Infundibulum give rise to?

The pituitary stalk, pars nervosa, posterior lobe, neurohypophysis .

The adenohypophysis( anterior pituitary) pars tuberalis and pars intermedia are formed from what structure?

The stomodeum

Fill in the blanks in response to their embryological origins. 1.____________ gives rise to Pouches. 2. ___________ gives rise to arches. 3. ______________ gives rise to clefts.

Endoderm - pouches Mesoderm - arches. Ectoderm - clefts

Fill in the blanks. " The dorsal bud of the 4th Pharyngeal pouch becomes _______."

Superior Parathyroid

Fill in the blanks. " The ventral bud of the 4th Pharyngeal pouch becomes _______."

Ultimobranchial body.

The Ultimobranchial body fuses with the thyroid gland and disseminates within it to give rise to what structure?

Parafollicular C cells

When does the Thyroid reaches it finals position?

Week 7

Fill in the blanks." The pancreas is formed by two buds originating from the ________."

Endodermal lining of the duodenum.

The ventral pancreatic bud gives rise to what structures?

Th uncinate process and inferior part of the head of the pancreas.

When does Insulin secretion begin?

In the fifth month

The main pancreatic duct is formed from what structures?

It is formed from the distal part of the dorsal pancreatic duct and the entire ventral pancreatic duct.

The accessory pancreatic duct is formed from what structure?

The proximal part of the dorsal pancreatic duct.

Which embryological origin forms the cortex of the suprarenal gland?

Mesoderm

Which embryological origin forms the medulla of the suprarenal gland?

Ectoderm

Fill in the blanks. "The hypothalamic-hypophyseal tract consists of axons extending from the ________ & _________."

Hypothalamic supraoptic and paraventricular nuclei.

What is the main function of the corpora arenacea” or “brain sand”?

They provide a good midline-marker for the brain.

What type of epithelium of found in the Thyroid gland?

Simple cuboidal epithelium

What is the name of the substance in which Chief (principal ) cells produce?

Parathyroid hormone.

What is the name of the substance with which C -cells produce?

Calcitonin C- cells aka Parafollicular cells

At what age do oxyphillic cells appear in life?

Occurs at age 6-7