Anatomy of Adrenal Glands

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Questions and Answers

What is the primary function of the adenohypophysis?

Storing hormones produced by the hypothalamus

Secreting hormones that regulate the activity of other endocrine glands (correct)

Producing enzymes for digestion

Regulating water balance and blood pressure

Which hormone is secreted by the thyrotropes in the adenohypophysis?

Thyroid-stimulating hormone (TSH) (correct)

Luteinizing hormone (LH)

Adrenocorticotropic hormone (ACTH)

Follicle-stimulating hormone (FSH)

Where is the pituitary gland located?

Behind the pancreas

In the thyroid gland

At the base of the brain (correct)

Next to the adrenal glands

Which gland works in conjunction with the pituitary gland?

Hypothalamus Signup and view all the answers

What type of cells in the adenohypophysis secrete prolactin (PRL)?

Lactotropes Signup and view all the answers

What are endocrine glands commonly called due to the way their hormones are released?

Ductless glands Signup and view all the answers

Which of the following glands is part of the endocrine system?

Pituitary gland Signup and view all the answers

Which endocrine gland is found in both males and females?

Pineal gland Signup and view all the answers

Where are the adrenal glands located?

On top of the kidneys Signup and view all the answers

Which organ is part of both the digestive and endocrine systems?

Pancreas Signup and view all the answers

Where is the thyroid gland located?

On the anterior and lateral surfaces of the trachea, just below the larynx Signup and view all the answers

How many lobes does the thyroid gland have?

Two Signup and view all the answers

What is the approximate weight of the thyroid gland in an adult?

30 gm Signup and view all the answers

What hormone do the principal cells in the parathyroid glands produce?

Parathyroid hormone Signup and view all the answers

What is the approximate weight of each parathyroid gland?

0.04 gm Signup and view all the answers

How many parathyroid glands are typically found in the human body?

4 Signup and view all the answers

What is the approximate weight of each adult adrenal gland?

3.5 to 5 grams Signup and view all the answers

Which zone of the adrenal cortex secretes mineralocorticoids?

zona glomerulosa Signup and view all the answers

What hormone is primarily secreted by the zona fasciculata?

glucocorticoids Signup and view all the answers

The adrenal medulla develops from the same embryonic tissue as which of the following?

sympathetic ganglia Signup and view all the answers

What percentage of the medullary secretion is epinephrine?

80% Signup and view all the answers

Which of the following functions is NOT associated with the adrenal medulla?

Secretion of aldosterone Signup and view all the answers

Which part of the adrenal gland is more involved in the body's response to stress?

Adrenal medulla Signup and view all the answers

Which of the following BEST describes the dual function of the pancreas?

Secretion of digestive juice and hormone release Signup and view all the answers

How is the anterior pituitary supplied with arterial blood?

Through a capillary bed in the hypothalamus and the pituitary portal system Signup and view all the answers

What triggers the release of anterior pituitary hormones?

Releasing and inhibiting hormones from the hypothalamus Signup and view all the answers

What is the main function of the neurohypophysis (posterior pituitary)?

Storing and releasing antidiuretic hormone (ADH) and oxytocin (OT) Signup and view all the answers

Which cells support the nerve cells in the neurohypophysis?

Pituicytes Signup and view all the answers

Where are the nerve cell bodies that synthesize posterior pituitary hormones located?

Supraoptic and paraventricular nuclei of the hypothalamus Signup and view all the answers

How are posterior pituitary hormones transported to the posterior pituitary?

Along the hypothalamohypophyseal tract Signup and view all the answers

What stimulates the release of hormones from the posterior pituitary?

Electrical impulses from the hypothalamus Signup and view all the answers

Which hormones are stored in the vesicles within the axon terminal of the posterior pituitary?

Antidiuretic hormone (ADH) and oxytocin (OT) Signup and view all the answers

Which of the following cells secrete glucagon?

Alpha or A cells Signup and view all the answers

What hormone is secreted by the pineal gland in response to light conditions?

Melatonin Signup and view all the answers

Which type of cell in the pancreatic islets secretes insulin?

Beta or B cells Signup and view all the answers

Where is the pineal gland located?

Near the roof of the third ventricle, between the cerebral hemispheres Signup and view all the answers

What do Delta or D cells in the pancreatic islets secrete?

Somatostatin (GHIH) Signup and view all the answers

What happens to melatonin secretion in the pineal gland when it gets dark?

Melatonin secretion increases Signup and view all the answers

What is another name for the pancreatic islets?

Islets of Langerhans Signup and view all the answers

What type of gland is the pineal gland?

Endocrine gland Signup and view all the answers

Study Notes

Adrenal Glands

Each adrenal gland is approximately 3-5cm in height, 2-3cm in width, and 1cm thick, weighing about 3.5 to 5gm.
During embryonic development, the adrenal gland differentiates into two structurally and functionally distinct parts: the outer cortex (80 to 90% of the gland) and the inner medulla.

The Outer Zone

The outer zone is the zona glomerulosa, which secretes mineralocorticoids that affect mineral (electrolyte) homeostasis.
The middle zone is the zona fasciculata, which is the widest of the three zones and secretes mainly glucocorticoids.
The inner zone is the zona reticularis, arranged in branching cords that synthesize a small amount of weak androgen with masculinizing effects.

Adrenal Medulla

The adrenal medulla is a modified sympathetic ganglion of the autonomic nervous system.
It develops from the same embryonic tissue as all other sympathetic ganglia, but its cells don't have axons and form clusters around small veins.
The adrenal medulla is composed of neurosecretory tissue, consisting of neurons specialized to secrete their hormones directly into the blood rather than across a synapse.
The two major hormones secreted by the adrenal medulla are epinephrine (adrenaline), accounting for about 80% of the medullary secretion, and norepinephrine (noradrenaline), accounting for the other 20% of the medulla's secretion.

Pancreatic Islets

The pancreas consists of two major types of secretory tissues, referred to as dual function.
The pancreas is an exocrine gland that secretes digestive juice and an endocrine gland that releases hormones.
The hormone-secreting cells of the pancreas are grouped in clusters, or islets, in close proximity to blood vessels.
There are three main types of cells in the pancreatic islets (islets of Langerhans): alpha or A cells that secrete glucagon, beta or B cells that secrete insulin, and delta or D cells that secrete somatostatin (GHIH).

Pituitary Gland

The anterior pituitary is supplied with arterial blood indirectly, first passing through a capillary bed in the hypothalamus.
The blood then passes through the pituitary portal system, which transports blood to the anterior pituitary.
Release of anterior pituitary hormones is stimulated by releasing hormones and suppressed by inhibiting hormones from the hypothalamus.
The neurohypophysis (posterior pituitary) does not synthesize hormones, but serves as a storage and release site for two hormones: antidiuretic hormone (ADH) and oxytocin (OT).

Endocrine System

The endocrine system is composed of endocrine glands located throughout the body.
The endocrine glands are ductless glands, as the hormones they release pass directly into the bloodstream.
The major endocrine glands include the hypothalamus, pituitary gland, pineal gland, parathyroid gland, thyroid gland, thymus, kidney, adrenal gland, pancreas, and ovaries and testes.

Pineal Gland

The pineal gland is a tiny, cone-shaped structure, reddish-brown in color, and surrounded by a capsule.
It is located deep between the cerebral hemispheres, attached to the upper portion of the thalamus near the roof of the ventricle.
The pineal gland secretes the hormone melatonin in response to light conditions outside the body.

Thyroid Gland

The thyroid gland is a butterfly-shaped gland located in the neck, on the anterior and lateral surfaces of the trachea, just below the larynx.
The weight of the gland in an adult is variable, but is around 30 gm, and it is a highly vascular gland surrounded by a fibrous capsule.

Parathyroid Glands

There are small parathyroid glands, two embedded in the posterior surface of each lobe of the thyroid gland.
Each parathyroid gland is surrounded by a thin capsule of connective tissue and consists of many tightly packed secretory cells, spherical in shape, closely associated with capillary networks.
The parathyroid glands contain two types of epithelial cells: principal cells that produce parathyroid hormone (parathormone), and oxyphil cells, whose function is not known.

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Description

This quiz covers the structure and development of the adrenal glands, including their size, components, and features.