Ch 18 Endocrine System Flashcards
Endocrine system-
Pituitary gland Parathyroid gland Thyroid gland Thymus gland Adrenal gland Pancreas Ovary Testes
Homeostasis
Ability to maintain a constant and optimal internal environment
Control system
System that coordinates, regulates and controls things within body
Nervous and endocrine are control system of body
All other systems are maintenance systems
Endocrine system do what
Release chemical messengers in blood ( carried by blood) aka hormone— attach to receptor to turn on or off
Communication process (hormonal) chemical messengers
Endocrine
Endocrine gland- hormone carried by blood- receptor proteins
Slow to respond but lasts longer
Lock and key system
Nervous system
Direct phone line- fast response, short lived
Neurotransmitter- axon- receptor protein
Neurotransmitter released by neurons
Neutransmitter and hormones can
In some instances swap places
Motor (effects)means
Getting an organ to do something
Primary endocrine organs main function
Pineal gland, hypothalamus, pituitary gland, thyroid gland, parathyroid gland, adrenal gland, ovaries, texture, placenta
To secrete hormone
Secondary endocrine organs/structures secrete hormones as
Hearts, stomach, liver, kidney, small intestine, skin
A secondary function, not main job
Glands
No major sensory component to endocrine system- not very capable of detecting stimulus. Can’t detect, can’t correct
release product to bloodstream directly
Hormones
Products deliver messages to body
Target cells
Have a specific receptor for specific hormone
Receptor
A protein found on the plasma membrane of a target cell that recognizes a specific hormone and can trigger a change in a cell
Nervous
Network of receptors that detect stimuli, send info to control (brain/spine), sends info to effector ( endocrine glands)
Maintain homeostasis
Detect stimulus- only nervous can detect these stimuli-
Activate nervous system via receptors sending info to brain
Endocrine system relies on
Sensory capabilities of nervous
Work as a team
Neuroendocrine response/ system
Combo of nervous and endocrine- due to close association
Neural control centers in the brain control
Endocrine glands
Nervous sends impulse to endocrine gland, gland releases hormone to coordinate function
Main neural control center is the
Hypothalamus aka master switchboard
Hypothalamus sends messages to what gland
Pituitary
Pituitary gland does what
Release hormones that regulate body functions
Suspended from hypothalamus by a thin stalk
Pituitary gland
Nervous and endocrine systems work together to carry out
Homeostatic responses
Endocrine
Sets control capabilities with hormones to coordinate and carry out effects by sending out chemicals.
Homeostatic response- activate/ inhibit network of cells
Crine (glands)
To secrete
Endocrine gland- within blood
Ductless that produce hormones and secrete them into blood
Secrete directly into bloodstream
Exocrine glands - outside - never enter blood
Glands that secrete its products into ducts which carry to destination
Ex- digestive enzymes, sweat glands, saliva
Hormone
Chemical messengers produced by endocrine cells and transported by blood
Inside or outside of what- endocrine vs. eco
The bloodstream
Anatomy of endocrine- classic glands
Pineal gland, pituitary gland, thyroid gland, adrenal gland, pancreas, ovaries, testes
Produce hormones to carry out regulatory process
What do glands have in common
Structural aspects (endocrine/ex)— difference is where they’re secreted
Recently discoverer
Other structures that can produce hormones, not just endocrine
Skin
Produces hormone/ steroid- vitamin D, secondary to protection- calcitriol
Lungs
Angiotensin- blood pressure
Heart
AMP- control sodium level and fluid and BP
Processes that endocrine work on- ongoing
Processes that last years/ entire lifespan-growth, reproduction, metabolism, water and electrolyte regulation
Issues here may lead to death
Functions- help control and integrate
Reproduction-28 day cycle ( controlled by hormone)
Growth- 18-22 yr (hormonal bone growth)
Development
Defense against stress- stress response (thyroid)
Water, electrolyte and nutrient balance-cardio/kidney- control loss/gain of water and electrolytes
Energy balance
Cellular metabolism
Endocrine system helps to maintain homeostasis by
Coordinating and regulating activities of cells, tissues, organs and systems throughout the body
What are the functions of the endocrine system
Water balance Uterine contractions Growth, metabolism, milk secretion Ion regulation Heart rate and BP regulation Blood glucose control Immune system regulation Reproduction function control
Nervous system may detect a need tis system carries it out
Endocrine
Parts of endocrine system
All depend on eachother
- glands, hormones, target cell, receptors
How do hormones work?
All work on same premise
Endocrine cell— secretes hormone— gets in to blood stream—- travels—- leaves blood stream and finds cell (target cell) —- hormone has to bind to receptor to be effective
Hormone receptor specificity
Lock and key theory
Each molecule has own 3 dimension aspect that correspond to receptor. This allows them to bind
Hormone receptor complex
Allows hormone and receptor to bind. Once complete this alters the function of the cell
Generally increase ( excitatory)or decrease ( inhibitory)
Hormones can be created in a lab?
True- as long as they fit the receptor, hormones can be created
Epinephrine
Hormone that causes less mucous to be created
Lab created decongestant- sudeph
Hormones can be blocked
Meds that block the receptor- attach to receptor to block hormone from binding
Beta Blocker’s
Lab created med to attach to receptor to block hormone from binding
For hormones to work
They have to be secreted and able to interact with a specific (target) cell
What is a target cell
Specific cell affected by hormone and responses in unique fashion
Cells have specific receptors on membrane or in cell that respond to hormone
Can have receptors for several different hormones
Target cell active receptors can change
Down regulation- number of receptors decreases and target is less sensitive
Up regulation - number increase and target is more sensitive
Will non target cells respond to a hormone?
No non target cell lacks receptor for hormone
Pituitary gland
Secretes TSH- thyroid stimulating hormone— only receptor is thyroid gland— activates only target- thyroid
All hormones interact with receptor- what how and where they interact are specific variables
Chemical nature cones in to play here
Steroid hormone
Testosterone, estrogen, progesterone
Derived from 1 group of chemicals- cholesterol-one, steron in name
Amine hormones- largest group- protein-
Epinephrine, norepinephrine T3, T4
Peptide hormone- protein
Oxytocin, vasopressin
Protein hormone
Insulin, glucagon
Glycoproteins - protein
LH, FSH
Eicosanoid hormones
Prostaglandins
Lipid derived from fatty acid ( arachidonic)
Long fatty acid
20 carbons
Classifying hormones
Response, organs they respond to, functions in common, chemical make up (what we are focusing on here)
Protein hormones are all what
Organic- meaning they have building blocks- made from amino acids
Prostaglandins ( eicosanoids)functions
Modify response to hormone Contribute to inflammation response Prevent stomach ulcers Dilate airways Regulate body temp Influence formation of blood clots
Leukotrienes
Allergy and inflammatory response
Eicosanoids function
Exert complex control over many bodily system ( inflammation, immunity, messengers is CNS
Found in most living things
Local hormones that are released by most cells, act in thst cell or nearby cell
Eicosanoids are what
Autocrine and paracrine mediators- rapidly inactivated
Forms of hormone in the circulation
Free molecules and bound molecules
Free molecules
Unbound
Water soluble hormone
Bound molecules
Water insoluble hormones
Bound with specific globulins or transport protein such as albumin
Cortisol binding globulin and thyroid binding globulin
How do hormones act on target cell’s
Lipid based hormones
Protein based hormone
Lipid based hormone — steroids
Hydrophobic and lipid-soluble
Diffuse across membrane and enter cells
Bind to receptor proteins and cytoplasm and nucleus
Bind to DNA as transcription factor
Protein based hormone- amino acidic
Hydrophilic and not lipid soluble
Can’t diffuse across membrane
Trigger secondary messenger pathway
Activate cellular response
Enzyme action uptake or secretion of molecules
Trigger secondary messenger pathway
How they dissolve in material
Protein- dissolve in water
Amino acids- not water soluble
Target cells have what
Cell membrane- made of phospolipid bilayers
Intracellular receptors
Used by steroid- lipid based hormone
In cytoplasm- aka cytoplasmic receptor
Protein hormone- outside cell
Use cell membrane receptor/ plasma membrane receptors
Cannot get I to cell
Location of receptor determines what?
What hormones it interacts with
And how hormones alter the functioning of the cell
Intracellular receptors- how they do their job
Largest group- steroids
Gland secretes hormone into bloodstream— transports protein (carrier)—- (bound hormone)— detaches from transport protein (free) —-reach destination, unhook from transport protein up to cell membrane— diffuse cell membrane— once inside it attaches to receptor—- receptor shuttles hormone to nucleus (chromosomes/ dna-genes)—- once inside looking for gene on the dna—- once it finds, the hormone (steroid) attaches to the gene— this activated the gene— this activates protein synthesis)
Only the free hormone can enter the cell
Gene
Structure in DNA responsible for a trait- traits are based in chemistry
Protein synthesis
Transcription and translation
- Gene active , gene has to copy if self- made of messenger RNA ( transcription- this process).
- RNA Leaves cell and attaches to ribosomes (work bench) — new protein (translation)
Proteins work through what
Second messenger system-
Travels through blood- these dissolve in blood- leaves stream and migrates to cell- receptor attached to cell membrane- hormone binds and makes hormone receptor complex— once hormone bonds it activates a G protein —- G protein activates adenlayte Cyclase( converses ATP to cAMP) cAMP- controls chemical reactivity in cell. Cell response is altered.
Signal transduction
Process that occurs after a hormone binds to a receptor
An intracellular signal is generated(second messenger) which delivers the hormonal message
Amplifies the original signal converting substrate molecules to products ( snowball effect) Turning 1 into millions
cAMP has to be removed- how?
Enzyme - PDE- inactivates ( once activated) cAMP- steps. Helical reaction in cell, allows cell to return to resting level
PDE how it works
Degrade phosphodiester bond in the second messenger cAMP and cGMP
PDE important regulators of signal transduction mediated by these second messenger molecules
PDE usually referred to as cyclic nucleotide phosphodisterases which have great clinical implications
PDE family; 11 isoenzyme families (PDE 1- PDE 11) with over 50 isoforms
PDE inhibitors
Don’t allow PDE to activate
Control PDE and we control
Control response of cell, by second messengers - enhance or lock certain activities to treat certain disorders
