The Endocrine System Flashcards
What are two of the main hormones produced by the pancreas?
The pancreas has endocrine cells which compose the islets of Langerhan. The α-cells produce and secrete glucagon and the β-cells produce and secrete insulin.
What cells secrete adrenocorticotropin (ACTH)?
Adrenocorticotropes (ζ amphophils) are stimulated by corticotropin-releasing hormone (CRH) to secrete adrenocorticotropin (ACTH).
What are ε acidophils and what product do they secrete?
Mammotropes, or lacticotropes, (ε acidophils) are stimulated by prolactin-releasing factor (PRF) to secrete prolatin (PRL).
What do atrial myocardial cells, or atrial myocardiocytes, produce and secrete?
Atrial myocardial cells, or atrial myocardiocytes, produce and secrete atrial natriuretic peptide (ANP).
What are the three parts of the anterior pituitary (adenohypophysis)?
The anterior pituitary (adenohypophysis) is composed of the pars distalis, pars intermedia, and the pars tuberalis.
What cells secrete follicle stimulating hormone (FSH)?
δ-2 basophils are gonadotropes that are stimulated by gonadotropin-releasing hormone (GnRH) to secrete follice-stimulating hormone (FSH).
What do the zona fasciculata cells of the adrenal cortex secrete?
The zona fasculata cells, or spongiocytes, of the adrenal cortex secrete glucocorticoids, such as cortisol and corticosterone.
What hormone is produced and released by the supraoptic nucleus of the hypothalamic nuclei?
The supraoptic nucleus of the hypothalamic nuclei produces and releases antidiuretic hormone (ADH) to the capillaries of the pars nervosa of the posterior pituitary (neurohypophysis). Release of antidiuretic hormone (ADH) occurs when the cell bodies of the supraoptic nucleus are stimulated by high blood osmocity. Once released into the capillaries, antidiuretic hormone (ADH) enters the bloodstream to target cells in the renal tubular collecting ducts, stimulating the kidney to increase water reabsorption, decreasing blood osmocity, and producing more concentrated urine.
What is the parathyroid gland composed of?
The parathyroid gland is composed of tightly packed chief cells.
What is/are the target organ(s) of follicle-stimulating hormone (FSH)?
δ-2 basophilic gonadotrophic cells produce follicle-stimulating hormone (FSH), which acts on the testes and ovaries.
What cells secrete thyroid-stimulating hormone (TSH)?
Thyrotropes (β basophils) are stimulated by thyrotropin-releasing hormone (TRH) to secrete thyroid-stimulating hormone (TSH).
What structure to steroid hormones bind to upon reaching their target cells?
Steroid hormones pass through the plasma membranes of their target cells and bind directly to the nucleus.
What are examples of polypeptide hormones?
Oxytocin and prolactin are polypeptide hormones.
What pancreatic cells produce and secrete insulin?
β-cells of the pancreas produce and secrete insulin.
What occurs when thyroglobulin is secreted from thyrofollicular epithelial cells?
Thyrofollicular epithelial cells, or the cells lining the follicles of the thyroid gland, secrete thyroglobulin via endocytosis and convert it to active triiodothyronine (T3) and tetraiodothyronine, which is also referred to as thyroxine (T4).
What pancreatic cells secrete glucagon?
The α-cells of the pancreas secrete glucagon.
What type of cardiac cells produce and secrete atrial natriuretic peptide (ANP)?
Atrial myocardial cells, or atrial myocardiocytes, produce and secrete atrial natriuretic peptide (ANP).
What are Herring bodies?
Herring bodies are swellings along the hypothalamic axons extending into the posterior pituitary (neurohypophysis) where hormones are stored prior to their release into the capillaries of the posterior pituitary (neurohypophysis).
What cells secrete luteinizing hormone (LH)?
δ-1 basophils are gonadotropes that are stimulated by gonadotropin-releasing hormone (GnRH) to secrete luteinizing hormone (LH).
What specific hypothalamic nucleus is responsible for the production and release of antidiuretic hormone (ADH)?
The supraoptic nucleus of the hypothalamic nuclei produces and releases antidiuretic hormone (ADH) to the capillaries of the pars nervosa of the posterior pituitary (neurohypophysis). Release of antidiuretic hormone (ADH) occurs when the cell bodies of the supraoptic nucleus are stimulated by high blood osmocity. Once released into the capillaries, antidiuretic hormone (ADH) enters the bloodstream to target cells in the renal tubular collecting ducts, stimulating the kidney to increase water reabsorption, decreasing blood osmocity, and producing more concentrated urine.
What is/are the target organ(s) of prolactin (PRL)?
Mammotrophic, or lactotrophic, cells (ε acidophils) secrete prolactin, which acts on the mammary glands and the testes.
What are the secretory cells of the pineal gland (epiphysis) and what hormone to they produce?
The secretory cells of the pineal gland (epiphysis) are pinealocytes. Pinealocytes produce and secrete variable amount of melatonin in response to stimuli detected in the retina. When light is not stimulating the retina (darkness), pinealocytes are stimulated to secrete melatonin. This produces every animals 24 hour circadian rhythm.
What is another name for the pineal gland?
The pineal gland is also known as the epiphysis cerebri.
What do pancreatic β-cells produce and secrete?
The β-cells of the pancreas produce and secrete insulin.
Where is melanocyte-stimulating hormone (MSH) secreted from?
Melanocyte-stimulating hormone (MSH) is released from the pars intermedia of the anterior pituitary (adenohypophysis).
What action does thyroid-stimulating hormone (TSH) have on the thyroid gland?
Thyroid-stimulating hormone (TSH) regulates the synthesis, iodination, and proteolysis of thyroglobulin.
What cells do endocrine organs originate from?
Endocrine organs originate from epithelial tissue, or the ectoderm of the developing embryo.
Identify the four regions of the histological section taken from a pituitary gland (hypophysis).
- Pars distalis of the anterior pituitary (adenohypophysis) = green
- Hypophyseal cleft = purple
- Pars intermedia of the anterior pituitary (adenohypophysis) = blue
- Pars nervosa of the posterior pituitary (neurohypophysis) - gold
What cells secrete prolactin (PRL)?
Mammotropes, or lacticotropes, (ε acidophils) are stimulated by prolactin-releasing factor (PRF) to secrete prolactin (PRL).
What are the secretory cells of the adrenal medulla?
Chromaffin cells of the adrenal medulla secrete epinephrine and norepinephrine, which is stored in secretory granules.
Explain the process in which hormones are released into the posterior pituitary (neurohypophysis) and subsequently systemic circulation.
The collection of neurons within the hypothalamus, or the hypothalamic nuclei, release hormones into the capillaries within the pars nervosa of the posterior pituitary (neurohypophysis). Hormones released into these capillaries continue through the bloodstream, into the collecting vein below the pituitary gland, where they enter systemic circulation to travel to their target tissues.
What do thyrofollicular epithelial cells produce and secrete?
Thyrofollicular epithelial cells, or cells lining the follicles of the thyroid gland, produce and secrete thyroglobulin.
What is another name for the pituitary gland?
The pituitary gland is also known as the hypophysis cerebri.
What are α acidophils and what product do they secrete?
Somatotropes (α acidophils) are stimulated by growth hormone-releasing hormone (GHRH) to secrete growth hormone (GH).
Identify the region of the adrenal gland shown in the histological section.
This is the zona glomerulosa of the adrenal cortex. You can identify this region by its increased vascularization and the arch-like orientation of the cells.
What are the different kinds of secretory cells that compose the islets of Langerhans in the pancreas?
The islets of Langerhans of the pancreas are composed of α-cells, β-cells, δ-cells, and F cells.
What are examples of amino acid hormones?
Triiodothyronine (T3), thyroxine (T4), and catecholamine (epinephrine and norepinephrine) are amino acid hormones.
What characteristic distinguishes endocrine glands from other glandular tissues?
The endocrine system is a ductless gland system that secretes its products internally or into an intracellular compartment whereas other glandular tissues secrete their products onto cell surfaces or into a duct.
Identify the two regions of the histological section taken from a pituitary gland (hypophysis).
What primary endocrine organ is present only in birds?
The ultimobranchial bodies are a primary endocrine organ that are only present in birds.
How do hormones reach their target cells?
Hormones are secreted by endocrine glands into the bloodstream where they remain until reaching their target tissues.
What cells compose the pars distalis of the anterior pituitary (adenohypophysis)?
The pars distalis of the anterior pituitary (adenohypophysis) is composed of two types of chromophils, acidophils and basophils, and chromophobes, which do not take up much of the stains.
What portion of the anterior pituitary (adenohypophysis is responsible for the majority of hormone secretion?
The pars distalis of the anterior pituitary (adenohypophysis) is responsible for the majority of hormone secretion.
What do pancreatic α-cells produce and secrete?
The α-cells of the pancreas produce and secrete glucagon.
What is the main function of the pineal gland (epiphysis)?
The main function of the pineal gland (epiphysis) is to maintain regular daily rhythyms of bodily activity.
What hormone is produced and released by the paraventricular nucleus of the hypothalamic nuceli?
The paraventricular nucleus produces and releases oxytocin in response to a neurological signal produced by neonatal or infant suckling. Stimulation of the paraventricular nucleus releases oxytocin into the capillaries of the par nervosa of the posterior pituitary (neurohypophysis), where oxytocin enter the bloodstream. Once in the bloodstream, oxytocin travels to myoepithelial target cells within the mammary gland, stimulating contraction of the milk producing alveoli, resulting in milk letdown.
Identify the region of the adrenal gland shown in the histological section.
This is an image of the adrenal medulla. This region is composed of chromaffin cells that have a columnar to cuboidal (“plump cuboidal cells”) with indistinct vacuoles.
What are the layers of the adrenal cortex?
The adrenal cortex has three layers:
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
Identify the region of the adrenal gland shown in the histological section.
This is an image of the zona reticularis layer of the adrenal cortex. You can identify this region by its high level of vasculature and the foamy appearance (lipid vacuoles) of the cells.
Identify the following structures on the histological section of the pituitary gland (hypophysis). Be sure to specify whether or not the structure is part of the anterior pituitary (adenohypophysis) or the posterior pituitary (neurohypophysis).
- Anterior pituitary (adenohypophysis) = gold
- Posterior pituitary (neurohypophysis) = green
Identify the labeled regions of the histological section of the thyroid gland.
- A: Thyroid follicle
- B: Parafollicular (clear) cells
- C: Thyrofollicular epithelial cells, lining cells of the thyroid follcile, or follicular cells of the thyroid gland
- D: Colloid, or thyroglobulin stored in the lumen of the thyroid follicle
Identify whether the thyroid follicles labeled A, B, and C are active or inactive. What are the distinguishing characteristics of an active and inactive thyroid follicle?
- Follicle A is an inactive thyroid follicle, which is indicated by the dark (“black”) cytoplasm of the thyrofollicular epithelial cells, flattened appearence of the thyrofollicular epithelial cells, and the “flush” edges of the follicle.
- Follices B and C are active thyroid follicles, which is indicated by the “scalloped” margins of the thyroid follicle and the clear, vaculated cytoplasm of the thyrofollicular epithelial cells.
Identify the structures identified on this histological section of the pars nervosa of the pituitary gland (hypophysis).
Herring bodies look like round hypereosinophilic areas around the pituicytes and are the storage sites of antidiuretic hormone (ADH) and oxytocin. Pituicytes provide structure and nourishment to the axons.
Identify the region of the adrenal gland shown in the histological section.
This is the zona fasciculata layer of the adrenal cortex. You can identify this region by its column-like organization of cells, called spongiocytes, and its decreased vascularization.
Identify the structure within the gold circle and the specific cells present within the red and green circles on the histological section of pancreatic tissue.
The encircled structure is an islet of Langerhans. However, you are unable to identify the specific cells that compose this structure without the use of special staining techniques.
Briefly describe the embryonic origin of the pituitary gland (hypophysis).
The primitive anterior pituitary (adenohypophysis) starts off as the hypophyseal pouch, which originates from an invagination of pharyngeal ectodermal cells (primitive oral epithelial cells). The primitive posterior pituitary (neurohypophysis) is called the neurohypophyseal bud, which is composed of neuroectodermal cells of the diencephalon.
