Endocrine System Flashcards
Release of GnRH from the hypothalamus triggers the anterior pituitary to release the gonadotropins called
FSH and LH
Where is CRH (corticotropin-releasing hormone) secreted?
Hypothalamus
Describe neural/synaptic communication
When the chemical messenger diffuses across the synaptic cleft
Describe endocrine communication
When the cells release their chemical messengers into the bloodstream
Describe paracrine communication
Occurs when the chemical messengers simply diffuse through the extracellular fluid to neighboring target cells
Describe autocrine communication
When a cell responds to the chemical messenger it secreted itself
What are the organs that have only endocrine function
Pineal Pituitary parathyroid thyroid adrenals
List the organs that have endocrine function as well as their primary function. (Hint:AHKLOPPSSST)
(A)dipose tissue (H)ypothalamus (H)eart (K)idneys (L)iver (O)varies (P)ancreas (P)lacenta (S)tomach (S)mall intestine (S)kin (T)estes
What are the three main functions of the major hormones
Homeostasis
digestion and metabolism
reproduction growth and development
What are the five chemical classes of hormones
Steroids: derived from cholesterol; lipid-soluble
peptides and proteins: chains of amino acids; water-soluble
Amines: catecholamines; water-soluble and thyroid; lipid-soluble
Eicosanoids: lipid-soluble
Retinoids: lipid-soluble
What kind of receptor does a lipid-soluble hormone bind to
Intercellular (p.40 lab)
What kind of receptor does a water soluble hormone bind to
Cell-surface (p. 41 lab)
What are the three factors that regulate hormone secretion
- other hormones
- neural mechanisms
- other substances (such as glucose or calcium ions dissolved in the blood)
Name the hormones released by the hypothalamus
Corticotropin-releasing hormone(CRH) Gonadotropin-releasing hormone (GnRH) Somatostatin growth hormone releasing hormone (GRH) prolactin release inhibiting factor (PIH) prolactin releasing factor (PRH) thyrotropin releasing hormone(TRH)
Anti diuretic hormone and oxytocin are synthesized here
Name the hormones secreted by the posterior pituitary
Antidiuretic hormone (ADH) Oxytocin
List the six hormones secreted by the anterior pituitary (HINT: FLAT PG)
F)ollicle-stimulating hormone L)uteinizing hormone A)drenocorticotropic hormone T)hyroid stimulating hormone P)rolactin G)rowth hormone
Name the hormones secreted by the thyroid gland
Thyroxine (T4)
Triiodothyronine
Calcitonin
Name the hormone secreted by the parathyroid gland
Parathyroid hormone
List the hormones secreted by the adrenal medulla
Epinephrine and norepinephrine
Name the hormones secreted by the adrenal medulla and the adrenal cortex
Cortisol (a mineralocorticoid; glomerulosa) Aldostersone (a glucocorticoid; fasciculata) Androgenic steroids (reticular is)
Norepinephrine (medulla/in middle)
Epinephrine (medulla/in middle)
Name the hormones secreted by the pineal gland
Melatonin
Name the hormones secreted by the pancreas
Glucagon (alpha cells)
Insulin (beta cells)
Somatostatin (Delta cells)
Pancreatic polypeptide (F cells)
Name the hormones secreted by the tested
Androgen
Inhibit
Name the hormones secreted by the ovaries
Estrogen
Progesterone
Inhibin
The hormones secreted from the placenta
Estrogen Progesterone Relaxin Human chorionic gonadotropin (hCG) Human chorionic somatomammotropin
Name the hormones secreted by the kidneys
Erythropoietin (EPO)
Renin (an enzyme not a hormone!!)
Name the hormone secreted by the stomach
Gastrin
Name the hormones secreted by the small intestine
Secretin
Cholecystokinin (CCK)
Gastric inhibitory peptide(GIP)
Name the hormones secreted by the liver
Somatomedin
Erythropoietin (EPO)
What does the skin secrete
Vitamin D3 (7-dehydrocholesterol)
What hormone does the heart secrete
Atrial natriuretic factor
What does adipose tissue secrete
Lepton
What cells secrete parathyroid hormone
Chief cells
Para follicular cells of the thyroid gland secrete___
Calcitonin
Give examples of signalling molecules involved in neural/synaptic communication ( hint:sands)
s) erotonin
a) cetylcholine
n) orepinephrine
d) opamine
s) ubstance P
Give examples of signalling molecules involved in endocrine communication (hint:patice)
p) rolactin
a) ldosterone
t) hyroxine
i) nsulin
c)ortisol
e) pinephrine
Give examples of signalling molecules involved in paracrine communication
(known as local hormones, paracrine hormones, local mediators, or local regulators) histamine prostaglandins somatostatin growth factors/cytokines leukotrienes
Give examples of signalling molecules involved in autocrine communication
prostaglandins and certain growth factors
How do endocrine glands differ from exocrine glands
exocrine glands secrete outside of the body and usually their secretions travel through a tube or duct. Endocrine glands are hormone-secreting
Give some examples of proteins and peptides
proteins:
insulin, GH, somatomedin, ACTH, LH, FSH, TSH
peptides:
TSH-releasing hormone, oxytocin, GnRH, Antidiuretic hormone, somatostatin
How are protein hormones synthesized
start out as big, inactive molecules called (preprohormones and prohormones) and are then chopped up by enzymes
How are proteins stored and released
They are stored in secretory granules and released by the process of exocytosis. Exocytosis is initiated by a rise in the concentration of Ca++ in the cytoplasm of the secreting cell.
List all the amine hormones, and name the amino acid from which they are synthesized
thyroxine (T4), triiodothyronine (T3), epinephrine, and norepinephrine. They are synthesized from tyrosine.
How are catecholamines (norepinephrine and epinephrine) stored and released
They are stored in cells as secretory granules and released by exocytosis
What substance is the starting point for synthesis of all the steroid hormones
Cholesterol
List 5 or more steroid hormones
estrogens androgens progesterone cortisol (adrenal cortex) aldosterone (adrenal cortex)
What substance is the starting point for synthesis of the eicosanoids
arachidonic acid
Give examples of eicosanoids
thromboxanes
lipoxins
leukotrienes
prostaglandins
what common substance inhibits the synthesis of eicosanoids
asprin
Give an example of a retinoid, starting point for synthesis, and what physiological process is it involved in
retinoic acid
starting point is retinol
vertebrae development
List the classes of hormones that are lipid-soluble
steroid
amines
eicosanoids
retinoid
list the classes of hormones that are water soluble
peptides and proteins
amines
What types of cellular receptors are there for lipid soluble hormoness
intracellular receptors (however, estrogens, cortisol, and thyroid hormone can also have cell-surface receptors and can act non-genomically)
Descibe the anatomy of the thyroid gland
The thyroid gland is located in front of the trachea and between the sternocleidomastoid muscles and below the laryx. It has a right and left lobe which are connected by the isthmus
Describe the synthesis of thyroid hormone
- Thyroid hormones are synthesized from the glycoprotein thyroglubulin
- In the colloid, iodine atoms are first added to the tyrosine amino acids in the thyroglobulin peptide chain
- The iodinated thyroglobulin is further processed to form “mature thyroglobulin” which is stored as colloid in the follices
Describe the release of thyroid hormone
- Thyroglobulin is endocytized by the follicular cells
- Lysosomal proteases carve out T3 & T4
- T3 & T4 in the ratio of 1:10 are transported in the blood by specific transport proteins
- T3 & T4 enter the target cells
- T3 & T4 then bind to intracellular receptor proteins. When activated by T3 & T4, these receptor proteins interact w/transcriptional enhancer elements found in the nuclear DNA. The transcriptional enhancers increase the rate of trascription and enhances gene expression
Describe the action of thyroid hormone
- Increase the rate of many metabolic reactions
- increase the rate and force of cardiac contraction and enhances response of cardiac tissue to catecholamines
- Stimulate growth hormone secretion necessary for bone and nervous system development
Describe the symptoms of hyperthyroidism
weight loss wide-eyed stare rapid heart rate tremor loss of muscle mass
Describe the cause of Grave’s disease and explain how it is treated
The body produces antibodies that bind to TSH receptors and mimic the effect of real TSH. This leads to the overproduction of thyroid hormone. Treatments: surgery, 131I, and drugs that block hormone synthesis
Describe the symptoms of hypothyroidism in children
(cretinism)
retardation of growth
slowing of ossification
failure to develop central nervous system
Describe the symptoms of hypothyroidism in adults
large weight gain
slow heartbeat
slowing of movement, speech, and thought
What cells secrete calcitonin and what is the function of calcitonin
Calcitonin is secreted by the C-cells of the thyroid gland. Calcitonin lowers blood calcium
What are the functions of calcium in t he body
building of bones and teeth contractoin of smooth, skeletal, and cardiac muscle blood clotting hormone secretion neurotransmitter release
What are consequences of hypoparathyroidism and how is it treated
(caused by damage or surgical removal)
lowers blood Ca++, causing muscle cramps, twitches, convulsions, and seizures
What is the exocrine function of the pancreas
Acinar cells secrete digestive enzymes that pass into the duodenum and via the pancreatic ducts
What is an anabolic process
The process of using smaller molecules to build larger ones
What is the endocrine function of the pancreas
Alpha cells: secrete glucagon
Beta cells: secrete insulin
Delta cells: secrete somatostatin
PP cells: secrete pancreatic polypeptide
What is the action of insulin on glucose
Promotes the synthesis of glycogen from glucose in inhibits it’s breakdown
What is the effect of insulin on fatty acid
Remote synthesis of facts from fatty acid and inhibits their breakdown
What is the effect of insulin on amino acids
Promotes synthesis of proteins from amino acids. Therefore insulin inhibits glyconeogenesis of the liver because it deprives the liver of amino acids
What is the effect of glucose on insulin
Stimulates insulin secretion
What is the effect of somatostatin on insulin
Somatostatin inhibits insulin secretion
List the hormones of the gonads
Ovaries: estrogens, progesterone, inhibin
Testes: androgens, inhibin
Describe the process of insulin secretion
When the glucose levels rise outside the Beta-cells, the glucose enters the cells via the GLUT2 transporter which leads to depolarization of the plasma membrane. This causes Calcium ions to enter the cells via the voltage-gated calcium channels. This rise of intracellular calcium ion concentration triggers fusion of insulin-containing vesicles with the plasma membrane and exocytosis of their contents.
What are the effects of high blood glucose
(hyperglycemia) increases the osmotic pressure in the extracellular fluid, leading to cell dehydration, including brain neurons
what are the effects of low blood glucose
(hypoglycemia) impairs the function of the brain
explain the effects of insulin overdose
low blood glucose => hypoglycemic shock
can lead to fainting, tiredness and weakness, headache
Where do you find the Islets ofLangerhans
the pancreas
