Endocrine glands Flashcards
Facilitates long distance communication
Nervous and Endocrine systems
Uses electrical signals
Nervous system
Uses hormones
Endocrine system
What are hormones?
- Chemical signaling molecules that travel in blood
- Reach most cells of the body
- Have widespread effects
How does the endocrine system maintain homeostasis?
It regulates:
1. Use of calories and nutrients
2. Secretion of wastes
3. Blood pressure and blood osmolarity
4. Growth
5. Fertility and sex drive
6. Lactation
7. Sleep
Chemical messengers used by endocrine system and most are released into blood
Hormones
Hormone that affects neighboring cells
Paracrine signaling
Hormone that affects the same cell that released it
Autocrine signaling
Hormone that travels through blood to affect cells throughout body
Endocrine signaling
Used by neurons and the nervous system
Neurotransmitters
Chemical secretions exit glands via?
Exocytosis
Endocrine gland secretion releases product into?
Bloodstream or extracellular fluid
Exocrine gland secretion releases product into??
Duct that carries products to a body surface
Endocrine glands include?
- Pituitary
- Thyroid
- Parathyroid
- Adrenal
- Pineal
Glands
Some have non-endocrine functions
Hormones
Do not have a duct for secretion
Endocrine Glands
Secretions enter blood or interstitial fluid
Endocrine glands
Hormones affect?
Target cells
Cells with receptors for that specific hormone
Hormone that affect target cells
Other organs that have endocrine functions contain??
Cells that have endocrine functions
What are the organs that have endocrine functions?
- Hypothalamus
- Thymus
- Heart
- Kidneys
- Stomach
- Small intestine
- Liver
- Adipose tissue
- Ovaries
- Testes
Allow control and communication of the body
Nervous and Endocrine systems
Generally faster to make a change
Nervous system
Has more widespread effects
Endocrine system
Effects generally last longer
Endocrine system
What are the different types of hormones?
Based on chemical structure:
1. Steroid hormones
2. Amine-based hormones
3. Peptide and protein hormones
Cross cell membrane easily; lipid-based hormones
Steroid Hormones
Modified amino acids; water soluble; cannot cross cell membranes
Amine-based hormones
Made from chains of amino acids; water soluble; cannot cross cell membranes
Peptide and protein hormones
Produced from cholesterol molecules
Steroid hormones
Examples of steroid hormones are
Testosterone and estrogen
Steroid hormones require ____ to travel in ____.
Transport proteins; blood
Do not require transport protein to travel in blood
Amine hormones and Peptide and Protein Hormones
What are examples of Amine hormones?
Melatonin, Epinephrine, and Norepinephrine
What are the examples of peptide and protein hormones?
Antidiuretic hormone and insulin
Made on demand by modifying cholesterol molecules
Steroid hormones
Cannot be stored; not soluble in blood
Steroid hormones
Travel bound to transport proteins when in blood
Steroid hormones
Translated like other proteins; modified and stored in vesicles until release; soluble in blood; travel in a free state
Peptide hormones
Receptors can be ____ or on the ______.
Intracellular; cell surface
Are usually intracellular (cytosol or nuclear)
Lipid-soluble hormone receptors
Why are lipid-soluble hormone receptors intracellular?
Because lipid-soluble hormones can pass through cell membrane
Are usually on surface of cell
Water-soluble hormone receptors
Why are water-soluble hormone receptors on the cell surface?
Because they are usually unable to cross cell membrane
Associated with steroid and thyroid hormones
Intracellular hormone receptors
Intracellular hormone receptors results in
Increased transcription and increased protein synthesis
Associated with water-soluble hormones; peptide and amine hormones
Membrane-bound hormone receptors
Hormone serves as first messenger in the pathway
Membrane-bound hormone receptors
A/an ____relays message inside the cell
Intracellular second messenger
Second messenger system
- Hormone binds to receptor in cell membrane
- G protein is activated
- G protein activates adenylyl cyclase
- Adenylyl cyclase converts ATP to cyclic adenosine monophosphate (cAMP)
- cAMP activates protein kinases
- Protein kinases phosphorylate proteins
- Phosphorylated proteins cause change
______ allows a small amount of hormone to cause significant change
Amplification
_______ breaks down ______ that quickly stops internal cellular changes
Phosphodiesterase (PDE) ; cAMP
Other second messenger systems may use ______ as a second messenger
Calcium ions
Decrease in receptor number
Downregulation
Increase in receptor number
Upregulation
Occurs when hormone level is chronically higher
Downregulation
Occurs when hormone levels are chronically low
Upregulation
Cells become more sensitive to hormone
Upregulation
Cells become less sensitive to hormone
Downregulation
