Endocrine System Flashcards
Endocrine glands
Secrete cell product into interstitial fluids around cell or into blood stream
Exocrine glands
Secrete cell product onto body surface (internal or external)
Hormones are chemical messengers that have to go through _______
Your blood
Neurotransmitters are chemicals that are released _______
Across a synapse
What are some examples of exocrine secretions?
Sweat, Tears, Gastrin
What jobs does the endocrine system have?
Regulation of:
- fluid balance and ion concentration
- absorption of nutrients
- metabolism and growth
- sexual characteristics and reproduction
- body’s response to stress
Does the endocrine system occur over short, rapid processes or slow, long processes?
Slow, long processes
Name the type of transmission, chemical mediators, and distribution of effects of Direct communication.
- Gap Junctions
- Ions, small solutes, lipid soluble materials
- Limited to adjacent cells of the same type that are connected
Name the type of transmission, chemical mediators, and distribution of effects of Paracrine communication
- Extracellular fluid
- Paracrine factors
- Limited to local area with high concentration, and target cells with appropriate receptors
Name the type of transmission, chemical mediators, and distribution of effects of endocrine communication.
- Circulatory system
- Hormones
- Target cells are on other tissues and organs and must have appropriate receptors
Name the type of transmission, chemical mediators, and distribution of effects of synaptic communication.
- Synaptic clefts
- Neurotransmitters
- Limited to a specific area; target cells must have appropriate receptors
Paracrine factors are nicknamed ______ despite the fact they are not hormones
Local hormones
Why are paracrine factors not hormones?
They diffuse into interstitial fluid only, not the blood.
Because hormones travel via blood, they reach almost all body cells but only produce effects in _____
Target cells that have receptors for the hormone
Do protein based or lipid based hormones take longer to be removed from the body?
Lipid based hormones
What are the three types of hormones?
Amines
Peptide hormones
Lipid derivatives
Name examples of an amine hormone
Norepinephrine
Epinephrine
Thyroid hormones
Name examples of peptide hormone
Insulin
Glucagon
Growth Hormone
All 9 pituitary hormones
The big faker of the hormones is _____ because it is actually an amine but acts as a lipid derivative to bind to a transport protein
Thyroid hormone
Name examples of lipid derivative hormone
Steroids (estrogen, testosterone, aldosterone)
The majority of hormones are ____
proteins
Protein hormones (amines and peptides) are soluble in your blood stream, so they are _______
freely circulating
Lipid derivatives have a cholesterol back bone so it doesn’t freely circulate in order to avoid
Blocking vessels
Lipid derivatives must be bound to a ______ to freely circulate
Transport protein
Which type of hormone takes the longest to break down?
Lipid derivatives
What type of effect does a protein based hormone have on a cell?
It binds to a receptor, activates cAMP or calcium (acts as a 2nd messenger) begins transcription translation to turn the cell on or off
What type of effect does a lipid based hormone have on a cell?
Passes directly through the cell membrane to turn the cell on or off and increase/decrease mitochondria production
Amines and peptide hormones produce an effect on a cell via a ______
Second messenger/ G protein
Lipid soluble hormones have receptors in the _____
Cytoplasm
Protein soluble hormones have receptors in the ____
Cell membrane
What types of hormones can cross the cell membrane?
Steroids and thyroid hormone
How do lipid soluble hormones produce an effect on a cell?
Controlling gene expression and ATP synthesis
Describe how insulin lets glucose into the cell
Insulin binds to receptor on cell membrane
G protein is activated
G protein activates cAMP production
cAMP (or calcium) acts as 2nd messenger
2nd messenger triggers transcription translation
Back door opens and lets glucose into the cell
When a peptide hormone binds to receptors on the surface of a cell:
A. The hormone receptor complex moves into the cytoplasm
B. The cell membrane becomes hyperpolarized
C. A 2nd messenger is produced or removed from cytoplasm
D. The hormone is transported to the nucleus where it alters the activity of DNA
C. a 2nd messenger is produced or removed from cytoplasm
Reflexes control endocrine activity via a ______ feedback loop
Negative
What contains most of the receptors that detects something needing to change in the body and triggers a hormonal response?
Hypothalamus
Simple endocrine reflexes are located in
The gland itself
Simple reflexes have an effect only on
The gland itself
What is an example of a simple endocrine reflex?
Glucose levels in blood control insulin release by endocrine cells of pancreas
Simple reflexes produce _____ effects while complex reflexes produce____ effects
Direct
Indirect
Complex endocrine reflexes involve
Two or more hormones
Name 3 examples of complex reflexes:
- TH controls release of TRH by hypothalamus
- TRH controls release of TSH by pituitary gland
- TSH control thyroid gland secretion of TH
Trace the pathway of thyroid hormone
Hypothalamus releases TRH into blood stream
TRH comes back and triggers release of TSH from adenohypophysis
TSH enters bloodstream and goes to Thyroid gland
Thyroid gland releases T4
Enzyme breaks a bond of T4 to make T3
What part of the pituitary gland is made up of neural tissue?
Neurohypophysis
The pituitary gland as a whole releases ______ hormones that are all _____ hormones
9 hormones
peptide hormones
Hormones released from the adenohypophysis is controlled by _______ secreted by the hypothalamus
Regulatory hormones
Hypothalamus neurons release regulatory hormones into fenestrated capillaries of the __________
hypophyseal portal system
What is the hypophyseal portal system?
capillary network surrounding the hypothalamus
What does a fenestrated capillary mean?
Hormones travel in and out super easily because of gaps present in the beds
Tropic hormones means that the hormone
does not have a direct effect
Most of the hormones released by the adenohypophysis have a ____ effect
Indirect
What hormones are considered gonadotropins?
FSH and LH
GnRH is only released at puberty if there is enough
body fat
In a male, a constant stream of _____ is produced
LH
Prolactin stimulates the development of ____ and ____
Mammary glands
Milk production
MSH stimulates _____ and is produced in very small amounts
melanin pigment production in skin
Growth hormone causes release of ______ from liver
somatomedins
What do somatomedins do?
increase in aa uptake in skeletal muscle and cartilage
Stimulates protein synthesis
Cell growth
______ has both direct and indirect effects
Growth Hormone
What is an indirect effect of GH?
Causes liver to produce somatomedins that will go to the entire body to pick up protein synthesis
What is a direct effect of GH?
Epithelial and connective tissue growth and breakdown of lipids
The hormones of the adenohypophysis are called tropic hormones because
They stimulate other glands to secrete hormones
The neurohypophysis secretes hormones in a different way than the adenohypophysis because
Hormones are secreted through axon terminals of nerve cells and into the capillary bed
What types of cells are present in the thyroid gland?
C cells and follicle cells
What do C cells produce, where are they located, and what effect does the secretion have on the body?
Calcitonin
Thyroid gland
Tones down calcium levels
Calcitonin _____ calcium levels while _____ increases it
tones down
pTH
What do follicle cells produce?
Thyroid hormones: thyroxine and triiodothyronine
What is the structure of thyroid hormones?
An amino acid attached to iodide ions
90% of thyroid secretions are
T4 (thyroxine)
____ is the active form of the thyroid hormone?
T3
Thyroid hormones are ____ but act as if they are _____
Amines
Lipid derivatives
The hypothalamus only has ____ receptors to monitor thyroid hormone
T4
What is the function of thyroid hormone?
To produce strong and short increase in the rate of cellular metabolism and use of energy
The thyroid hormone does not need a membrane receptor, so it simply enters the cell and binds to ____ to increase energy production
mitochondria
Thyroid hormone deficiency is worse when you are a _____ because you are still growing
Child
Low thyroid hormone could lead to
Stunted growth
effected bones, muscles, and nervous system
What is hypothyroidism?
Low thyroid hormone
weight gain
tiredness
low body temp
What is hyper thyroidism
High thyroid hormone
caused by Grave’s disease
weight lost
high body temp
What is goiter?
Enlarged thyroid gland
Not enough iodine in diet
Why does iodine effect thyroid function?
Thyroid continuously makes precursers of thyroid hormone to be stored in follicle cavities. When iodine is in the diet, it kicks out the thyroid hormone. If you don;t have enough iodine, the hormone builds and builds
What type of levels does a person with goiter have?
Low levels of T3 and T4
High levels of TSH
Which of the following would be expected in a case of a tumor that causes hyper-parathyroidism
A. levels of PTH go up
B. Calcium ion concentrations would become abnormally high
C. Bones would become weakened due to loss of calcium
D. all of the above
D. all of the above
Adrenal medulla secretes
Epinephrine
Norepinephrine
(but mostly epinephrine)
The adrenal cortex secretes
steroid hormones (aldosterone, glucocorticoids, androgens)
The adrenal cortex is stimulated by ______ to secrete steroid hormones
ACTH
Andgrogens
produce testosterone
80% of adrenal medulla’s secretions are
Epinephrine
Epinephrine secretion causes
breakdown of glycogen in liver
Breakdown of fat to release fatty acfids
Increased cardiac contractions
Parasympathetic stimulation is _____ while sympathetic stimulation is _____
Localized
Widespread
Pineal gland secretes
Melatonin
Which of the following endocrine glands are composed of neural cells?
Adrenal medulla
Posterior pituitary gland
Most of the pancreas is made up of ____ cells
Exocrine cells
The endocrine cells of the pancreas release hormones involved in the
regulation of blood glucose levels
Alpha cells secrete ______ in the pancreas
glucagon in response to low blood sugar
Beta cells secrete _____ in the pancreas
insulin in response to high blood sugar
The pancreas is the only gland that secretes enzymes that break down all
macromolecules
Insulin
- lowers blood sugar
- increases glucose uptake in insulin dependent cells
- increased uptake of fatty acids and synthesis of triglycerides
- increased uptake of amino acids and synthesis of proteins
All cells are insulin dependent except
neural cells
Glucagon
- raises blood sugar
- increases glycogen breakdown
- increases glucose manufacture by liver
- increased release of fatty acids from adipose tissue
If glucagon is released, glycogen breakdown would look like what in the liver and muscle?
- glucose remains in muscle cells
- glucose released into blood from liver
What is diabetes insipidus?
Polyuria
Inadequate ADH secretion
What is diabetes mellitus
Polyuria
Glycosuria
Hyperglycemia
Type 1 diabetes is where
Your body attacks the beta cells of your pancreas so you stop producing insulin and cannot get glucose into your cells
Type 2 diabetes is where
Receptor for insulin on a cell is blocked so insulin cannot open the cell to let glucose in
Adipose tissue secretes what two hormones?
Leptin and resistin
What does leptin do?
feedback control for appetite
What does resistin do?
Reduces insulin sensitivity (blocks insulin receptors)
Kidneys secrete hormones that
regulate blood volume
blood pressure
blood calcium
