[Biology] Ch.5: The Endocrine System Flashcards
What is the difference between type 1 and type 2 diabetes mellitus
Type 1 is an autoimmune disease in which insulin-producing cells in the islets of Langerhans are destroyed and type 2 is caused by end-organ insensitivity to insulin
What do hormones do at the tissue when they bind to receptors
They induce a change in gene expression or cellular functioning
What are the three kinds of hormones
Peptides, steroids, or amino acid derivatives
What are peptide hormones derived from
From larger precursor polypeptides that are cleaved during posttranslational modification
Where do peptide hormones bind
Extracellular receptor
What are some common second messengers
Cyclic adenosine monophosphate (cAMP), inositol triphosphate (IP3), and calcium
What’s an example of cAMP intracellular targets
Protein kinase A
Why is protein kinase A able to have a rapid or slow effect on the cell
Because they can modify other enzymes as well as transcription factors
Steroid hormones are derived from [ 1 ] and are produced primarily by the [ 2 ] and the [ 3 ]
1) cholesterol 2) gonads 3) adrenal cortex
Steroid hormone receptors are usually [ 1 ] or [ 2 ]
1) intracellular 2) intranuclear
Why are the effects of steroid hormones slower but longer lived than that of peptide hormones
Because steroid hormones cause alterations to the amount of mRNA and protein present in a cell by direct action on DNA
What are epinephrine, norepinephrine, triiodothyronine, and thyroxine examples of
Amino acid-derivative hormones
What are thyroid hormones made from and what is the difference between them
They’re made of tyrosine and differ with the number of iodines added
Catecholamines (epinephrine and norepinephrine) bind [ 1 ] while the thyroid hormones bind [ 2 ]
1) G protein-coupled receptors 2) intracellularly
What is the difference between direct and tropic hormones
Direct hormone act directly on target tissue while tropic hormones require an intermediary to act
What are two examples of tropic hormones
GnRH and LH
Why do tropic hormones usually originate in the brain and anterior pituitary
These structures are involved in coordination of multiple processes within the body
[ 1 ] and [ 2 ] have extremely fast onset but are short lived like [ 3 ] hormones
1) epinephrine 2) norepinephrine 3) peptide
[ 1 ] and [ 2 ] have slower onset but a longer duration like [ 3 ] hormones
1) thyroxine 2) triiodothyronine 3) steroid
Most peptide and amino acid-derivative hormones have names that end in [ 1 ] or [ 2 ] and most steroid hormones have names that end in [ 3 ], [ 4 ], or [ 5 ]
1) -in 2) -ine 3) -one 4) -ol 5) -oid
List the endocrine glands (8)
The hypothalamus, pituitary, thyroid, parathyroid glands, adrenal glands, pancreas, gonads, and pineal gland
Where is the hypothalamus located; what are nearby structures
In the forebrain directly above the pituitary gland and below the thalamus
How does the hypothalamus control the pituitary
Through paracrine release of hormone into a portal system that directly connects the two organs
How is release of hormones from the hypothalamus regulated
Through negative feedback
What is the benefit of negative feedback
Prevents wasted energy by restricting the production of substances that are already present in sufficient quantities
What four hormones released by the hypothalamus lead to release of by the anterior pituitary
- Gonadotropin-releasing hormone (GnRH)
- Growth hormone releasing hormone (GHRH)
- Thyroid-releasing hormone (TRH)
- Corticotropin-releasing factor (CRF)
What does GnRH stimulate the anterior pituitary to release
FSH and LH
What does GHRH stimulate the anterior pituitary to release
Growth hormone
What does TRH stimulate the anterior pituitary to release
Thyroid stimulating hormone
What does CRF stimulate the anterior pituitary to release
Adrenocorticotropic hormone (ACTH)
What is the relationship between the hypothalamus and prolactin
The hypothalamus secretes prolactin-inhibiting factor (PIF) (which is actually dopamine) and causes a decrease in prolactin secretion
How does the posterior pituitary receive tropic hormones
Neurons in the hypothalamus send their axons down the pituitary stalk directly into the posterior pituitary
What two hormones does the posterior pituitary release
Oxytocin and antidiuretic hormone
What does oxytocin do
Stimulates uterine contractions during labor and milk letdown during lactation + there’s evidence it’s involved in bonding behavior
Recite the mnemonic for the products of the anterior pituitary
FLAT PEG
- Follicle stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Adrenocorticotropic hormone (ACTH)
- Thyroid stimulating hormone (TSH)
- Prolactin
- Endorphins
- Growth hormone (GH)
the FLAT hormones are all tropic hormones and the PEG hormones are all direct hormones
Why is prolactin more important in females than in males
It stimulates milk production in the mammary glands
What do endorphins do
They decrease the perception of pain
What does growth hormone do
It promotes growth of bone and muscle
How does growth hormone increase the availability of glucose for muscle and bone
It prevents glucose uptake in certain tissues and stimulates the breakdown of fatty acids
Why is oxytocin unusual
It’s regulated by positive feedback
What are the two major functions of the thyroid
Setting basal metabolic rate and calcium homeostasis
What are the shorthand’s for triiodothyronine and thyroxine
T3 and T4 respectively
What 3 ways does calcitonin use to decrease plasma calcium levels
- Increased calcium excretion from the kidney
- Decreased calcium absorption from the gut
- Increased storage of calcium in the bone
What is the relationship between parathyroid hormone (PTH) and calcitonin
PTH serves as an antagonistic hormone to calcitonin
What does PTH do
It raises blood calcium levels by decreasing the excretion of calcium by the kidneys and increasing the absorption of calcium in the gut (via vitamin D) and increasing bone reabsorption
How does PTH play a role in phosphate homeostasis
reabsorbing phosphate from bone and reducing phosphate reabsorption in the kidneys (leading to it being excreted in urine)
Does PTH have a net effect on phosphate levels
Not really because it activates vitamin D (which helps with both calcium and phosphate reabsorption)
What are the four critical functions of calcium
- Bone structure and strength
- Release of neurotransmitters from neurons
- Regulation of muscle contraction
- Clotting of blood (calcium is a cofactor)
What role does calcium play on a (single) cellular level
- Cell movement
- Exocytosis of cellular materials
Where are the adrenal glands located
On top of the kidneys
What are the similarities and the difference between glucocorticoids, mineralocorticoids, and cortical sex hormones
- All steroid hormones secreted by the adrenal cortex
- Glucocorticoids = regulate glucose levels
- Mineralocorticoids = salt and water homeostasis
- Cortical sex hormones = sex-related development and such
Recite the mnemonic to remember the functions of the corticosteroids
S^3
- Salt (mineralocorticoids)
- Sugar (glucocorticoids)
- Sex (cortical sex hormones)
Why is the adrenal medulla a part of the sympathetic nervous system
It produces the sympathetic hormones epinephrine and norepinephrine
The pancreas has [ 1 ] and [ 2 ] functions
1) exocrine 2) endocrine
What to the alpha, beta, and delta cells of the islets of larger Hans produce
Glucagon, insulin, and somatostatin respectively
What is the relationship between somatostatin, insulin, and glucagon
Somatostatin is an inhibitor of insulin and glucagon secretion
What stimulates the secretion of somatostatin
High blood glucose and amino acid concentrations
What is the function of somatostatin when secreted by the hypothalamus
It decreases growth hormone secretion
The testes secrete [ 1 ] and the ovaries secrete [ 2 ] and [ 3 ] in response to [ 4 ] (FSH and LH)
1) testosterone 2) estrogen 3) progesterone 4) gonadotropins
Where is the pineal gland located and what does it secrete
It is located deep in the brain and secretes melatonin
What stimulates the kidneys to produce erythropoietin
Low oxygen levels in the blood
Erythropoietin stimulates [ 1 ] to increase production of [ 2 ]
1) Bone marrow 2) erythrocytes
Why does the heart release atrial natriuretic peptide (ANP)
To help regulate salt and water balance
What stimulates the heart to secrete ANP
When cells in the atria are stretched from excess blood volume
Where is the thymus located
Located behind the sternum
What does thymosin, the hormone secreted by the thymus, do
It is important for proper T cell development and differentiation
The hypothalamus is the bridge between the [ 1 ] and [ 2 ] systems
1) nervous 2) endocrine
describe the source, type, and action of: Follicle-stimulating hormone (FSH)
- Anterior pituitary
- Peptide
- Stimulates follicle maturation in females and spermatogenesis in males
describe the source, type, and action of: Luteinizing hormone (LH)
- Anterior pituitary
- Peptide
- Stimulates ovulation in females and testosterone synthesis in males
describe the source, type, and action of: Adrenocorticotropic hormone (ACTH)
- Anterior pituitary
- Peptide
- Stimulates the adrenal cortex to synthesize and secrete glucocorticoids
describe the source, type, and action of: Thyroid-stimulating hormone (TSH)
- Anterior pituitary
- Peptide
- Stimulates the thyroid to produce thyroid hormones
describe the source, type, and action of: Prolactin
- Anterior pituitary
- Peptide
- Stimulates milk production and secretion
describe the source, type, and action of: Endorphins
- Anterior pituitary
- Peptide
- Decreases sensation of pain; can promote euphoria
describe the source, type, and action of: Growth hormone (GH)
- Anterior pituitary
- Peptide
- Stimulates growth and muscle growth; raises blood glucose levels
describe the source, type, and action of: Antidiuretic hormone (ADH; vasopressin)
- Hypothalamus (released by posterior pituitary)
- Peptide
- Stimulates water reabsorption in the kidneys by increasing permeability of collecting duct
describe the source, type, and action of: Oxytocin
- Hypothalamus (released by posterior pituitary)
- Peptide
- Stimulates uterine contractions during labor and milk secretion during lactation; may promote bonding behavior
describe the source, type, and action of: Triiodothyronine (T3) and thyroxine (T4)
- Thyroid (follicular cells)
- Amino-acid derivative
- Stimulates metabolic activity
describe the source, type, and action of: Calcitonin
- Thyroid (parafollicular or C cells)
- Peptide
- Decreases blood calcium concentrations
describe the source, type, and action of: Parathyroid hormone (PTH)
- Parathyroids
- Peptide
- Increases blood calcium concentrations
describe the source, type, and action of: Glucocorticoids (cortisol and cortisone) (3)
- Adrenal cortex
- Steroid
- Increases blood glucose concentrations; decreases protein synthesis; anti inflammatory
describe the source, type, and action of: Mineralocorticoids (aldosterone) (2)
- Adrenal cortex
- Steroid
- Increases water reabsorption in the kidneys by increasing sodium reabsorption; promotes potassium and hydrogen ion excretion
describe the source, type, and action of: Epinephrine and norepinephrine (3)
- Adrenal medulla
- Amino acid-derivative
- Increases blood glucose concentrations and heart rate; dilates bronchi; alters blood flow patterns
describe the source, type, and action of: Glucagon
- Pancreas (alpha cells)
- Peptide
- Stimulates glycogen breakdown (glycogenolysis); increases blood glucose concentrations
describe the source, type, and action of: Insulin
- Pancreas (beta cells)
- Peptide
- Lowers blood glucose concentrations and increases anabolic processes
describe the source, type, and action of: Somatostatin
- Pancreas (delta cells)
- Peptide
- Suppresses secretion of glucagon and insulin
describe the source, type, and action of: Testosterone
- Testis (and adrenal cortex)
- Steroid
- Develops and maintains male reproductive system and male secondary sex characteristics
describe the source, type, and action of: Estrogen
- Ovary (and placenta)
- Steroid
- Develops and maintains female reproductive system and female secondary sex characteristics
describe the source, type, and action of: Progesterone
- Ovary (and placenta)
- Steroid
- Promotes maintenance of the endometrium
describe the source, type, and action of: Melatonin
- Pineal gland
- Peptide
- Involved in circadian rhythms
describe the source, type, and action of: Erythropoietin
- Kidney
- Peptide
- Stimulates bone marrow to produce erythrocytes
describe the source, type, and action of: Atrial natriuretic peptide (ANP)
- Heart (atria)
- Peptide
- Promotes salt and water excretion
describe the source, type, and action of: Thymosin
- Thymus
- Peptide
- Stimulates T-cell development
