Lecture #20 Endocrine System Flashcards
What are some of the similarities between the Endocrine and Nervous system?
Both act together to coordinate body activites (control processes)
Both systems use chemical messengers for intercellular communitication (gap junctions released one cell to the next)
Main homeostasis
What are some of the differences betwee the Endocrine and Nervous system?
In the Nervous system, the signals we look at are Action Potential, intensity of cell, and frequency of action potential–also the messaging speed is extremely fast in (milliseconds to seconds)
The endocrine system, are hormones realease by one type of cells influencing a target cell–message is slower (second to minutes, days to weeks, affect for a long period of time)
What are the major endocine glands?
Pituitary Gland Thyroid Parathyroid Adrenal Gland Pineal Gland Pituitary Gland
What are the major endocrine organs?
Hypothalamus Thymus Pancreas Overies/testes Kidneys Liver Stomach Heart Skin Adipose Tissue
What are exocrine glands?
Secrete products into ducts or lumens or the outer surface of the body such like tears, sweat, and mucous
Which can cause chemicals to arise from these glands, secretion of chemicals, and skin surface
What are endocrine glands?
secrete products into interstitial fluid which diffuse into blood rather than into ducts such as blood in the capillaries
What are local hormones?
Act locally that reach near by cells, not one self without first entering through bloodstream
What are the two types of local hormones?
Paracrine: act on neighboring cells
Autocrine: act on the same cell that produced them
Do hormones serve as a mediator molecule that can be released to one part of the body that regulate activity in other parts of the boyd?
True. Their called Local hormones and circulating hormones.
What is an example of a local hormone?
IL-2 released from help T cells stimulates proliferations of helper T cells and activation of Cyotoxic T cells
Histomine released by mast cells stimulates HCl secretion from parietal cells in stomach
What are circulating hormones?
Enter intersitial fluid and then the bloodstream
Carry throughout the blood vessel to target cell
What type of circulating homrones are there?
Lipid soluble and water soluble hormones
What are lipid soluble hormones?
They are bound to transport proteins for transport in body fluids
What are water soluble hormones?
They freely dissolved in body fluids
Are steroid hormones lipid soluble?
Yes.
What steroid hormones?
Derive from cholesterol
Have chemical groups attached to core of structure makes it unique
What are some examples of steroid hormones?
Corisol, Testorone,
Estrogens, Progestrone, Aldosterone
Are thyorid hormones lipid soluble?
Yes, very lipidy soluble.
What are thyroid hormones made of?
Made of tyrosin ring with attached iodines–synthesized by attaching iodine to the amino acid tyrosine (T3 & T4)
What are Water soluble hormones?
Peptide and protein hormones and biogenic amines
What are peptide and protein hormones made of?
Chains of amino acids
What part of the brain helps with releasing and inhibiting hormone called for the peptide and protein hormone?
Hypothalamic releasing and inhibiting hormones
What are some examples for Peptide and protein hormones?
ADH, oxytocin, hGH, TSH, ACTH
Insulin, glucagon, EPO
Are Biogenic Amines water soluble?
Yes
What are biogenic amines?
Modified Amino acids
What are some examples of Biogenic Amines?
Catecholamines: NE, epinephrine, dopamine
Serotonin, melatonin, histamine
What are the functions of the hormones?
Hormones are released from glands in response to internal and external changes
Hormones produce wide reaching, coordinated effects on multiple target tissues, and help to main homeostasis
How do hormones regulate the organ system function?
Ion and nutrient levels in extracellular fluid and blood
Metabolic Pathways
Biological clock
Contraction of cardiac and smooth muscle
Glandular secretion
Some immune functions
Growth & Development
Reproduction
How do circulating hormones work?
Hormones only affect target cells with specific membrane or intracellular proteins called hormone receptors
All hormones have 1 or more types of target cells. To be a target cell for a hormone, all a cell must do is have a receptor for that hormone… True or false?
True
How do circulating hormones bind to cells?
Can bind on the cell surfaces or to receptors inside target cell
How does a cell know when to respond?
Synthesis of new molecules
Change in membrane permeability
Altered rates of reaction
Do different target cells respond to the same hormone diffrently?
Yes!
For examples: Hepatocytes–insulin stimulates glycogen sythesis
Adipocytes–insulin stimulates triglyceride synthesis
What happens with steroid hormones when they react to the cell?
Receptors are typically intracellular
Work by changing the level of specific gene expression–leading to slow response
Draw out and expalin the cycle of steroid hormone action.
- Lipid soluble hormone diffuses into cell
- Activated receptor–hormone complex alters gene expression
- Newly formed mRNA directs synthesis of specific proteins on ribsomes
What is going on with the peptide hormone action?
Peptide hormones bind to cell surface receptors
Peptide hormones evoke changes in activity of existing proteins through a second messenger
Second messengers alter the phosphorylation state of existing proteins—response to water soluble hormones is very fast!
Draw out and describe the process of peptide hormone action.
- Binding of hormone (1st messenger) to its recpetor activates a specific G protein, which activates adenylate cyclase
- Activated adenylate cyclase converts ATP to cAMP
- cAMP serves as a 2nd messenger to activate protein kinase
- Activated protein kinases phosphorylate cellular proteins
- Millions of phosphorlated proteins cause reactions that produce physiological responses
- Phosphodieterase inactivates cAMP
Is it water soluble or lipid soluble hormones cause a producition of sencond messengers?
Water soluble (peptide) hormones
What are second messengers?
They happen when peptide hormones bind to the cell surface receptors and the first messerger hormones can increase or decrease the levels of the second messengers
What are some examples of second messengers?
cAMP
Calcium ions
cGMP
Can the same hormone be used with different second messengers in different target cells (for example: NE)?
YES!
What do second messengers initiate?
A cascade of biochemcial reactions, often involving phosphorlaytion or dephosphorylation, within target cells
