The Endocrine System Flashcards
The two systems that coordinate human body activities
Nervous and endocrine
Nervous system is quick in response and uses _________.
Neurotransmitters
Endocrine system is slow in response and uses _______ (chemical messengers in blood) – discipline is called ________.
- Hormones
- Endocrinology
Endocrine glands are _______ and unimpressive.
Small
The two kinds of glands in human body
Exocrine and endocrine
________ include pituitary, thyroid, parathyroid, adrenal, pineal and thymus; also gonads and pancreas.
Endocrine glands
Walls of stomach and small intestine, kidney, heart, hypothalamus are also in this category – also called ____________.
Neuroendocrine organs
_______ are chemical substances secreted by cells into extracellular fluid, are transported by blood and affect target organs and regulate metabolic activities.
Hormones
Example of _________ fits hormone actions
Airborne waves and appliances
Categories of hormones
- Amino acid based (water soluble)
- Steroid based (fat soluble)
Hormones cause changes in plasma membrane ________.
Permeability
Hormones cause synthesis of proteins or _______ molecules.
Regulatory
Hormones cause ______ activation or deactivation.
Enzyme
Hormones cause _______ of secretory activities of cells.
Induction
Hormones cause stimulation of ______.
Mitosis
For hormone action, _____ rather than speed is more important.
Duration
Amino acid based hormones cannot enter cell membrane because they are _________.
Water soluble
Amino acid based hormones work though a __________.
Second messenger
Most understood mechanism is the ______________.
Cyclic adenosine monophosphate (cAMP) mechanism
Three proteins involved:
- A ________ in the target cell plasma membrane
- A _________ (a G protein)
- An ________ (adenylate cyclase)
- Hormone receptor
- Signal transducer
- Effector enzyme
Endocrine cell –>
Hormone (________) in blood –>
Hormone binds to target cell membrane receptor –>
Receptor bound effector (_______) converts an ATP into cAMP (__________) –>
cAMP then alters preexisting intracellular enzyme activities and other properties of target cells
- First messenger
- Adenylate cyclase
- Second messenger
Examples of hormones using the ______ mechanism
ACTH, TSH, PTH, glucagon, calcitonin, FSH, LH, epinephrine, norepinephrine
cAMP
The Pituitary Gland (Hypophysis) is located at the _____ of the brain and weighs about _____.
- Base
- 0.5 g
Endocrine cells –>
Steroid hormones in blood –>
Hormone enters target cell membranes –>
Hormone binds to an ________ complex which in turn binds to an acceptor molecule on the __________
- Intracellular receptor-chaperon
- DNA in the nucleus
Using steroid hormones, interaction with DNA leads to synthesis of ________ resulting in synthesis of ______ that alter target cell activities.
- Specific mRNA
- Specific proteins
The 3 regions of the Posterior Pituitary or Neurohypophysis
- The median eminence (a funnel shaped downward extension)
- The infundibular stem
- The infundibular process
The Posterior Pituitary or Neurohypophysis consists of 2 major nuclei of neurons located in hypothalamus.
Supraoptic and paraventricular
Posterior Pituitary or Neurohypophysis cells are large with _______ and abundant cytoplasm.
Eccentric nuclei
The Posterior Pituitary stores ______ or _______ from _______ which functions in retention of water and vasoconstriction of arteriolar smooth muscles.
- Antidiuretic hormone (ADH) or Vasopressin
- Supraoptic nucleus
The Posterior Pituitary stores ______ from _________ which functions in stimulation of uterine smooth muscle contraction for child birth and milk ejection from mammary glands.
- Oxytocin
- Paraventricular nucleus
Posterior Pituitary or Neurohypophysis cells are large with _______ and abundant cytoplasm.
Eccentric nuclei
Posterior Pituitary or Neurohypophysis cells have axons with numerous dilatations containing neurosecretory granules called ________.
Herring Bodies
Posterior Pituitary or Neurohypophysis cells also have ______ as supporting cells
Pituicytes
The posterior pituitary does not synthesize any hormones but ______ hormones produced in ________ for a later release.
- Stores
- Hypothalamus
Of the chromophilic cells, the basophils are pink staining with PAS+ cytoplasm and three kinds of cells identified:
- ________ – ~15 %, located in periphery and produce thyroid stimulating hormone (TSH)
- ________ - widely distributed round or ovoid cells with small granules – produce adrenocorticotrophic hormone (ACTH)
- ________ with prominent Golgi complex, ER and situated close to sinusoids – produce follicle stimulating hormone (FSH) and luteinizing hormone (LH)
- Thyrotrophs
- Corticotrophs
- Gonadotrophs
The chromophobic cells (chromophobes) are situated in the interior of _______, have _____ cytoplasm, and make up 65% of all cells of pars distalis. They are considered as _______ and _______.
- Pars distalis cords
- Less
- Degranulated acidophils and basophils
The chromophobic cells (chromophobes) are situated in the interior of _______, have _____ cytoplasm, and make up 65% of all cells of pars distalis. They are considered as _______ and _______.
- Pars distalis cords
- Less
- Degranulated acidophils and basophils
The Pars Tuberalis forms a thin sleeve around ______ and is the most vascularized subdivision of the hypophysis.
-Hypohyseal stalk
The _______ consists of cords of parenchymal cells, thin walled sinuses and non secretory cells.
Pars Distalis
The Glandular cells of the Pars Distalis includes _______ cells, which are Acidophils and Basophilic, and ________ cells.
- Chromophilic
- Chromophobic
The Non secretory cells of the Pars Distalic includes _________ which are supporting epithelial cells.
Follicular (Stellate) cells
The Pars intermedia has considerable interspecific variations. In adult humans it is ________. The cells of intermedia secrete ___________.
- Not distinguishable
- Melanocyte stimulating hormone (MSH)
Hormones from the Anterior Pituitary (6)
- Growth Hormone (GH) or Somatotropin
- Thyroid Stimulating Hormone (TSH) or Thyrotropin
- Adrenocorticotropic Hormone (ACTH)
- Prolactin (PRL)
- Follicle Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
Hormone responsible for overall growth and intermediary metabolism.
Growth Hormone (GH) or Somatotropin
Hormone that stimulates growth of thyroid gland and secretion of its hormones.
Thyroid Stimulating Hormone (TSH) or Thyrotropin
Hormone that stimulates growth of adrenal cortex and secretion of cortisol.
Adrenocorticotropic Hormone (ACTH)
Hormone that is responsible for breast development & milk production in females and has an unknown function in males.
Prolactin (PRL)
Hormone that is responsible for growth and development of ovarian follicles and secretion of estrogens in females and regulation of sperm production in males.
Follicle Stimulating Hormone (FSH)
Hormone that is responsible for ovulation, luteinization, regulation of ovarian secretions of estrogens and progesterone in females and stimulates Leydig cells to secrete testosterone and intestinal cell stimulating hormone (ICSH) in males.
Luteinizing Hormone (LH)
Hormone that is responsible for ovulation, luteinization, regulation of ovarian secretions of estrogens and progesterone in females and stimulates Leydig cells to secrete testosterone and intestinal cell stimulating hormone (ICSH) in males.
Luteinizing Hormone (LH)
The thyroid gland is situated below larynx, two lobes connected by ______ and enclosed in a capsule. Its function is under the control of thyroid stimulating hormone (TSH) from anterior pituitary.
Isthmus
The thyroid gland produces hormones for ______ and ______. ______ and ______ regulate rate of metabolism. ______ regulates Ca++ in extracellular fluid and its deposition in bone.
- Normal growth and development
- Thyroxin (T4) and triiodothyronine (T3)
- Calcitonin
Most endocrine glands have limited ______ capability.
Storage
Thyroid gland is unique for _________ of the hormone in its luminal follicles, which are bounded by _______.
- Extracellular storage
- Simple cuboidal epithelium
Cells of the thyroid gland are polarized toward lumen and filled with a gelatinous substance called _______.
Colloid
T3 and T4 are stored in the colloid which is ________.
Thyroglobulin is a glycoprotein and must be hydrolyzed to release hormones.
Thyroglobulin + hormone
The two types of cells of the thyroid gland are ________ and ________.
- Principal or Follicular Cells
- Parafollicular Cells
The Principal or Follicular Cells produce _______ and ________.
T3 (triiodothyronine) and T4 (thyroxine)
The primary function of the thyroid gland is to produce _______ mediated by _____.
- Hormones
- TSH
Mechanism of hormone action for thyroid gland is through _____.
cAMP
In the thyroid gland, T3 and T4 affect stimulation at _________.
Transcriptional level
_______ results in decreased metabolism and stunted growth.
Hypothyroidism
_________ results in increased metabolism, weight loss, nervousness, fatigue and increased heart rate.
Hyperthyroidism
Calcitonin regulates ____ (decreases blood Ca++)
Ca++
The Parafollicular Cells are located between bases of principal cells, are 2-3 X larger than principal cells, comprise only 0.1% of cell population, and produce ______ (a peptide) and store in granules.
Calcitonin
_____ is important in muscle contraction, glucose secretion, blood coagulation, enzyme action, nerve impulse transmission etc.
Ca++
Two types of cell of Parathyroid Gland
- Chief cells
- Oxyphil cells
Two types of cell of Parathyroid Gland
- Chief cells
- Oxyphil cells
Chief cells have a central nucleus, are eosinophilic, and have coarse granules with pre-__________ which is later converted into PTH.
Pro parathyroid hormone
Oxyphil cells are larger in size, fewer than chief cells, and considered a ________ of chief cells.
Different phase
The principal function of the Parathyroid Gland is to produce and release PTH, which increased the ________.
Blood Ca++ level
The Parathyroid gland appears as small oval bodies located on the posterior side of ______, usually four in number.
Thyroid gland
The Parathyroid gland is enclosed in a thin capsule and their parenchyma is a _________.
Cluster of epithelial cells
Adrenal glands are embedded in adipose tissue at the ______ of each kidney. The cortex (80-90 % of volume) and medulla (10-20 % of volume) are both endocrine glands.
Cranial pole
The adrenal cortex has three concentric zones that are distinguishable:
- A thinner _________
- A broad intermediate _________
- An inner _________
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
Zona
glomerulosa
Mineralocorticoids (aldosterone)
Zona
fasiculata
Glucocorticoids (cortisol)
Zona
reticularis
Sex steroids (androgens)
Medulla
Catecholamines (epinephrine and norepinephrine)
______ has cells columnar and joined by desmosomes and golgi complex pointing toward nearest blood vessels.
Zona
glomerulosa
The zona glomerulosa has cytoplasm with fewer lipid droplets and less extensive ______. It’s cells produce ________, which are involved in ________ in renal tubules.
- Smooth ER
- Mineralocorticoids (ex: Aldosterone)
- Na+ reabsorption and K+ secretion
_______ has pale staining polyhedral cells arranged in long columns which are one or two cells thick and cells larger than those of glomerulosa cells.
Zona Fasciculata
The Zona Fasciculata has Cytoplasm with large number of lipid droplets, very extensive ________ (40-45 % of cell volume). Its cells produce __________ which controls __________.
- Smooth ER
- Glucocorticoids ( ex: Cortisol)
- Metabolism of carbohydrates
_______ has cells that are smaller than those in fasciculata and the smooth ER less extensive, Golgi complex is small and fewer lipid droplets.
Zona Reticularis
The Zona Reticularis has cytoplasm with large aggregations of _________ and cells that produce ______ that are responsible for ___________.
- Lipofuscin pigments
- Androgens
- Male sexual characteristics
________ has large epithelial cells arranged in rounded clusters and cytoplasm with large number of membrane bound granules.
Adrenal Medulla
Adrenal Medulla has two kinds of chromaffin cells that are distinguishable:
- Norepinephrine storing cells with _____ acid phosphatase activity
- Epinephrine storing cells with ______ acid phosphatase activity
- Negative
- Positive
Adrenal Medulla has two kinds of chromaffin cells that are distinguishable:
- Norepinephrine storing cells with _____ acid phosphatase activity
- Epinephrine storing cells with ______ acid phosphatase activity
- Negative
- Positive
Endocrine Pancreas: Islets of Langerhans (1-2 % of Pancreas)
-Alpha cells
(location, amount, granules, mitochondria, golgi complex, hormones)
Location: Periphery Amount: Next to beta Granules: Large/dense Mitochondria: Smaller Golgi complex: Less prominent Hormones: Glucagon
Endocrine Pancreas: Islets of Langerhans (1-2 % of Pancreas)
-Beta cells
(location, amount, granules, mitochondria, golgi complex, hormones)
Location: Throughout Amount: 70% Granules: Less dense Mitochondria: Larger Golgi complex: More prominent Hormones: Insulin
Endocrine Pancreas: Islets of Langerhans (1-2 % of Pancreas)
-Gamma cells
(location, amount, granules, mitochondria, golgi complex, hormones)
Location: Throughout Amount: Third Granules: Heterogeneous Mitochondria: N/A Golgi complex: N/A Hormones: Somatostatin
Endocrine Pancreas: Islets of Langerhans (1-2 % of Pancreas)
-F cells
(location, amount, granules, mitochondria, golgi complex, hormones)
Location: Scattered Amount: Least Granules: N/A Mitochondria: N/A Golgi complex: N/A Hormones: Pancreatic polypeptide
Hormones from endocrine pancreas control carbohydrate metabolism using the hormones _____, _____, and ______.
- Glucagon
- Insulin
- Somatostatin
________ increases blood sugar level through glycogenolysis.
Glucagon
________ decreases blood sugar level through driving sugar into cells and promoting glycogenesis.
Insulin
________ suppresses the secretion of glucagon and insulin.
Somatostatin
Deficiency of insulin causes ________, an impairment of glucose utilization that leads to increased blood sugar levels and ______ (glucose in urine).
- Diabetes melitus
- Glucosuria
The Pineal Gland is a ______ gland in the middle of the brain. In humans it is a conical and gray body.
Small
The Pineal Gland was formerly considered as a vestigial organ with no function, but is now well known to be an endocrine gland. Its activity is influenced by _________.
Cycles of light and dark
The Pineal Gland was formerly considered as a vestigial organ with no function, but is now well known to be an endocrine gland. Its activity is influenced by _________.
Cycles of light and dark
The Pineal Gland is invested by _______ and has pale staining epithelial cells called _______.
- Pia mater
- Pinealocytes
The Pineal Gland has rough and smooth ER, golgi complex, and mitochondria present, cell processes that contain microtubules, the nucleus is ________, and cytoplasm is basophilic.
Indented
The principal hormone from the Pineal Gland is ________, which is not _______ (it is released as it is synthesized).
- Melatonin
- Stored
The other cell type in the pineal gland is ________ which are analogous to neuroglial cells.
-Interstitial cells
In humans, the pineal gland contains peculiar extracellular concretions called ____________, which consists of _______ and _______ in organic matrix – mode of formation and function are poorly understood
- Corpus arenacea or brain sand
- Calcium phosphates
- Carbonates
It is now established that the pineal gland modulates _________.
Gonadal function
Effects of Melatonin on Reproductive Function:
- Seasonal changes in day length have profound effects on reproduction in many species
- Melatonin is anti-gonadotropic. It inhibits the secretion of the gonadotropic hormones such as ______ and _______ from the anterior pituitary
- Luteinizing hormone
- Follicle stimulating hormone
Effects of Melatonin on Sleep and Activity:
- Melatonin levels are lower in _________
- Other sleep disorders associated with melatonin are those seen in ______, and disruption of circadian rhythms as in ______.
- Elderly insomniacs
- Shift workers
- Jet lag