Endocrine System Flashcards
____ consists of a group of glands which are widely separated and have no physical connection with each other.
Endocrine System
____ are a group of glands found in the Endocrine System.
Endocrine glands
Endocrine glands are typically ____ in origin.
epithelial
Endocrine glands are epithelial in origin, that aggregated as ____ or ____ and surrounded by extensive network of capillaries.
cords or clusters
____ release signaling products called Hormones.
Secretory cells
Secretory cells release signaling products called ____.
Hormones
Endocrine glands are also referred to as _____.
Ductless Glands
Why are Endocrine glands referred to as Ductless glands?
Because they diffuse directly into the bloodstream
____ are chemical substances that act like messenger molecules in the body.
Hormones
____ maintain the constancy of chemical composition of extracellular and intracellular fluid.
Hormones
Hormones are directly released from the ____ into the ____ and carried to the site.
tissue, bloodstream
____ are directly released from the tissue into the bloodstream and carried to the site.
Hormones
Difference between Endocrine and Exocrine Glands
Exocrine Glands:
* Contain ducts
* Merocrine, Holocrine, Apocrine Secretion
Endocrine Glands:
* Lack ducts
* Paracrine, Juxtacrine, Autocrine
Three Methods of Secretion of Endocrine Hormones
- Paracrine
- Juxtacrine
- Autocrine
Which Method of Secretion
It occurs between the cells in close proximity with each other.
Paracrine Secretion
Which Method of Secretion
It is dispersal in interstitial fluid or through short loops of blood vessels.
Paracrine Secretion
Which Method of Secretion
Example: Gastrin made by pyloric G cells reaches target cells in the fundic glands.
Paracrine Secretion
Which Method of Secretion
The signaling molecule remains on the secreting cell’s surface or adjacent extracellular matrix and affects target cells when the cells make contact.
Juxtacrine Secretion
Which Method of Secretion
Example: Embryonic and regenerative tissue interactions
Juxtacrine Secretion
Which Method of Secretion
The cells may produce molecules that act on themselves.
Autocrine Secretion
Which Method of Secretion
Example: Insulin-like growth factor (IGF) produced by several cell types may act on the same cells that produced it.
Autocrine Secretion
____ is also known as the Hypophysis.
Pituitary Gland
Pituitary gland is also known as the ____.
Hypophysis
The ____ lies below the brain in a small cavity on the sphenoid bone.
Pituitary gland
____ is the small cavity located on the sphenoid bone.
Sella turcica
Pituitary gland develops from the ____ and ____.
dveloping brain and oral cavity
Neural Component of Pituitary Gland
Neurohypophyseal Bud
Oral Component of Pituitary Gland
Hypophyseal (Rathke) Pouch
During the ________, the neurohypophyseal bud forms from the diencephalon that will become the future posterior pituitary gland, while hypophyseal pouch grows from the roof of the pharynx that will become the future anterior pituitary gland.
third week of development
The ____ forms from the diencephalon.
Neurohypophyseal bud
The neurohypophyseal bud forms from the ____.
diencephalon
____ becomes the future posterior pituitary gland.
Neurohypophyseal bud
The ____ forms from the roof of the pharynx.
Hypophyseal pouch
The hypophyseal bud forms from the ____.
roof of the pharynx
____ becomes the future anterior pituitary gland.
Hypophyseal pouch
Two Major Parts of the Pituitary Gland
- Posterior Pituitary (Neurohypophysis)
- Anterior Pituitary (Adenohypophysis)
____ is also known as the Neurohypophysis.
Posterior Pituitary Gland
The posterior pituitary gland is also known as the ____.
Neurohypophysis
____ is also known as the Adenohypophysis.
Anterior Pituitary Gland
The anterior pituitary gland is also known as the ____.
Adenohypophysis
The ____ has a part called the pars nervosa, which develops as a down growth of the developing brain and is attached in the hypothalamus by the infundibulum.
Posterior pituitary gland (Neurohypophysis)
____ develops as a down growth of the developing brain.
Pars nervosa
Pars nervosa is attached in the hypothalamus by the ____.
infundibulum
The ____ includes the large pars distalis, the pars tuberalis that surrounds the infundibulum, and the thin pars intermedia adjacent to the pars nevosa.
Anterior pituitary gland (Adenohypophysis)
The ____ surrounds the infundibulum.
Pars tuberalis
The ____ is adjacent to the pars nervosa.
Pars intermedia
____ is also known as the Pituitary Portal System.
Hypothalamic-Hypophyseal Portal System
Hypothalamic-Hypophyseal Portal System is also known as the ____.
Pituitary Portal System
____ is a network of vessels that transport blood from the hypothalamus to the anterior pituitary.
Hypothalamic-Hypophyseal Transport System
Pituitary Portal System carries ____ to the adenohypophysis where they either stimulate or inhibit hormone release by endocrine cells.
neuropeptides
Components of the Hypothalamic-Hypophyseal Transport System
- Primary Capillary Plexus
- Secondary Capillary Plexus
____ is found in the infundibulum and lower hypothalamus.
Primary Capillary Plexus
____ is found in the pars distalis, connected by portal veins and draining to the hypophyseal vein.
Secondary Capillary Plexus
Secondary capillary plexus is connected by ____.
portal veins
____ is a bundle of axons from two important hypothalamic nuclei.
Hypothalamic-Hypophyseal Tract
Two Important Hypothalamic Nuclei
- Supraoptic Nuclei
- Paraventricular Nuclei
____ contains neurosecretory cells that produce Antidiuretic Hormone (ADH) or Vasopressin.
Supraoptic Nuclei
____ contains neurosecretory cells that produce Oxytocin.
Paraventricular Nuclei
____ is released in response to the increased blood tonicity.
Antidiuretic Hormone (ADH) or Vasopressin
____ increases the permeability of renal collecting ducts to water so that more water is reabsorbed from the filtrate.
Antidiuretic Hormone (ADH) or Vasopressin
____ stimulates contraction of uterine smooth muscle during childbirth and the myoepithelial cells in the mammary gland.
Oxytocin
Endocrine Cells of the Anterior Pituitary Gland
- Chromophils
- Chromophobes
____ are secretory cells in which hormone is stored in cytoplasmic granules.
Chromophils
____ have a few or totally lack secretory granules and stain poorly.
Chromophobes
Cell groups under Chromophils
- Acidophils
- Basophils
Cells produced by acidophils
- Somatotroph
- Lactotroph
____ produces Somatotropin (growth hormone).
Somatotroph
Somatotroph produces ____.
Somatotropin (Growth Hormone)
____ produces Prolactin.
Lactotroph
Lactotroph produces ____.
Prolactin (PRL)
Cells produced by basophils
- Gonadotroph
- Thyrotroph
- Corticotroph
____ produces Follicle Stimulating Hormone (FSH).
Gonadotroph
____ produces Luteinizing Hormone (LH).
Gonadotroph
Gonadotroph produces ___.
- Follicle Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
____ produces Thyroid Stimulating Hormone (TSH).
Thyrotroph
Thyrotroph produces ____.
Thyroid Stimulating Hormone
____ produces Adrenocorticotropic Hormone (ACTH).
Corticotroph
____ produces Beta-Lipotropin Hormone (LPH).
Corticotroph
Corticotroph produces ____.
- Adrenocorticotropc Hormone (ACTH)
- Beta-Lipotropin Hormone (LPH)
Corticotroph synthesizes the protein ____.
Proopiomelanocortin (POMC)
____ has neurosecretory neurons that secretes hypothalamic hormones which controls the secretions of all the hormones produced by the pituitary glands.
Hypothalamus
____ controls the activity of the pituitary glands.
Hypothalamus
____ will start the production of other hormones.
Releasing hormones
____ will stop the production of other hormones.
Inhibiting hormones
The hypothalamic releasing and inhibiting hormones are carried directly from the hypothalamus to the anterior pituitary glands via _______.
Hypothalamic-Hypophyseal Portal System
Releasing Hormones
- Prolactin-Releasing Hormone (PRH)
- Thyrotropin-Releasing Hormone (TRH)
- Gonadotropin-Releasing Hormone (GnRH)
- Corticotropin-Releasing Hormone (CRH)
- Growth Hormone-Releasing Hormone (GHRH)
____ prompts the anterior pituitary to produce prolactin.
Prolactin-Releasing Hormone (PRH)
____ triggers the release of thyroid stimulating hormone.
Thyrotropin-Releasing Hormone (TRH)
____ stimulates the anterior pituitary to release FSH and LH.
Gonadotropin-Releasing Hormone (GnRH)
____ sends a message to the anterior pituitary gland to produce ACTH.
Corticotropin-Releasing Hormone (CRH)
____ prompts the anterior pituitary to release growth hormone.
Growth Hormone-Releasing Hormone (GHRH)
Inhibiting Hormones
- Growth Hormone-Inhibiting Hormone (GHIH) or Somatostatin
- Prolactin-Inhibiting Hormone (PIH) or Dopamine
____ is also known as Somatostatin.
Growth Hormone-Inhibiting Hormone (GHIH)
Growth Hormone-Inhibiting Hormone (GHIH) is also known as _____.
Somatostatin
____ is also known as Dopamine.
Prolactin-Inhibiting Hormone (PIH)
Prolactin-Inhibiting Hormone (PIH) is also known as ____.
Dopamine
____ is the structure that connects the neurohypophysis to the hypothalamus.
Hypothalamic-Hypophyseal Tract
____ is the structure that connects the adenohypophysis to the hypothalamus.
Hypothalamic-Hypophyseal Transport System
____ is located anterior and inferior to the larynx.
Thyroid Gland
Thyroid gland consists of ____ lobes united by an isthmus.
2
The lobes of thyroid gland is connected by the ____.
Isthmus
The thyroid gland originates in early embryonic life from the foregut ____ near the base of the developing tongue.
endoderm
____ consists of many spherical follicles which are composed of simple epithelium.
Thyroid Gland
The thyroid gland consists of many spherical follicles which are composed of ____.
simple epithelium
Two Cell Types of Thyroid Gland
- Follicular Cells
- Parafollicular Cells (C Cells)
Hormone/s produced by Follicular Cells
- Triiodothyronine (T3)
- Thyroxine (T4)
Triiodothyronine (T3) is produced by ____.
Follicular cells
Thyroxine is produced by ____.
Follicular cells
____ helps to control the basal metabolic rate in cells throughout the body.
- Triiodothyronine (T3)
- Thyroxine (T4)
Hormone/s produced by Parafollicular Cells
Calcitonin
Calcitonin is produced by ____.
Parafollicular cells (C cells)
____ is triggered by elevated blood Ca2+ levels, and it inhibits osteoclast activity.
Calcitonin
____ are four small ovoid masses located on the back of the thyroid gland.
Parathyroid Gland
Parathyroid hormone is derived from the ____.
embryonic pharyngeal pouches
Endocrine cells of the parathyroid glands are called ____.
Principal (Chief) Cells
Parathyroid glands secrete ____.
Parathyroid hormone (PTH)
____ is an important regulator of blood calcium levels.
Parathyroid hormone
____ indirectly stimulates osteoclasts to elevate levels of calcium in the blood.
Parathyroid hormone (PTH)
____ inhibits osteoclast activity, lowering blood calcium levels.
Calcitonin
____ are paired organs lying near the superior poles of the kidneys, embedded in the pararenal adipose tissue and fascia.
Adrenal Glands
Two Concentric Regions of the Adrenal Gland
- Adrenal cortex
- Adrenal medulla
The ____ is the yellowish concentric zone of adrenal glands.
adrenal cortex
The ____ is the reddish-brown central concentric zone of adrenal glands.
adrenal medulla
The adrenal cortex of each adrenal gland consists of ____ concentric zones.
3
What kind of hormones are produced by the cells in adrenal glands?
Steroid hormones
Zones of Adrenal Cortex
- Zona Glomerulosa
- Zona Fasciculata
- Zona Reticularis
____ is the superficial zone of adrenal cortex.
Zona Glomerulosa
Which Zone of Adrenal Cortex?
- 15% of cortex
- Round cluster of cells
Zona Glomerulosa
____ produces Mineralocorticoids (Aldosterone).
Zona Glomerulosa
Zona Glomerulosa produces ____.
Mineralocorticoids (Aldosterone)
____ regulates electrolyte levels.
Aldosterone (Mineralocorticoids)
____ is the middle zone of adrenal cortex.
Zona Fasciculata
Which Zone of Adrenal Cortex?
- 65% - 85% of cortex
- Elongated strands of cells
Zona Fasciculata
____ produces Glucocorticoids (Cortisol).
Zona Fasciculata
____ regulates several aspects of carbohydrate metabolism.
Cortisol (Glucocorticoids)
____ is the innermost zone of adrenal cortex.
Zona Reticularis
Which Zone of Adrenal Cortex?
- 10% of cortex
- Smaller irregular cords of cells
Zona Reticularis
____ produces Dehydroepiandosterone (Androgens).
Zona Reticularis
____ is converted to testosterone or estrogen.
Androgens (Dehydroepiandosterone)
The ____ is composed of large, pale-staining polyhedral cells arranged in cords or clumps and supported by a reticular fiber network.
adrenal medulla
____ contains neural-crest derived chromaffin cells.
Adrenal medulla
____ synthesizes catecholamine (epinephrine or norepinephrine).
Chromaffin cells
____ regulates stress response.
- Epinephrine
- Norepinephrine
____ stimulate glycogen breakdown, elevating blood glucose levels. Together these effects augment the capability for defensive reactions or escape of stressors, the fight- or-flight response.
- Epinephrine
- Norepinephrine
____ is also known as Epiphysis Cerebri.
Pineal Gland
Pineal Gland is also known as ____.
Epiphysis Cerebri
____ regulates the daily rhythms of bodily activities.
Pineal gland
Pineal gland develops from embryonic ____.
neuroectoderm
Pineal gland contains modified neurons called ____.
Pinealocytes
____ secretes the amine Melatonin.
Pinealocytes
____ released from pinealocytes are promoted by darkness and inhibited by daylight.
Melatonin
____ helps in maintaining circadian rhytmn.
Melatonin
Pineal landmarks are the concentrations called ____.
Corpora Arenacea (brain sand)
____ are also known as Islets of Langerhans.
Pancreatic Islets
Pancreatic Islets are also known as ____.
Islets of Langerhans
____ are compact spherical or ovoid masses of endocrine cells embedded within the acinar exocrine tissue of the pancreas.
Pancreatic Islets
Pancreatic islets are located mostly in the glands ____.
narrow tail region
Pancreatic islets constitute ____ of the organ’s total volume.
1-2%
Cells of islets are ____ in shape.
polygonal or rounded
Pancreatic islets produce ____ of α-cells.
20%
____ produce Glucagon.
α-cells or A cells
A cells or α-cells produce ____.
Glucagon
____ acts on several tissues to make energy stored in glycogen and fat available through glycogenolysis and lipolysis; increases blood glucose content.
Glucagon
Pancreatic islets produce ____ of β-cells.
70%
____ produce Insulin.
β-cells or B cells
B cells or β-cells produce ____.
Insulin
____ acts on several tissues to cause entry of glucose into cells and it promotes decrease of blood glucose content.
Insulin
Pancreatic islets produce ____ of δ-cells.
5% - 10%
____ produce Somatostatin.
δ-cells or D cells
D cells or δ-cells produce ____.
Somatostatin
____ inhibits release of other islet cell hormones through local paracrine action, and inhibits release of GH and TSH in anterior pituitary and HCl secretion by gastric parietal cells.
Somatostatin
Pancreatic islets produce ____ of PP cells.
rarely
____ produce Pancreatic Polypeptide.
PP cells
____ stimulates activity of gastric chief cells; inhibits bile secretion, pancreatic enzyme and bicarbonate secretion, and intestinal motility.
Pancreatic Polypeptide