Unit 3 Lecture 21 Flashcards
Define the endocrine system
The collection of glands that produces hormones to maintain homeostasis
What are the similarities between the nervous system and the endocrine system?
- act together to control body activities
2. both use chemical messengers for intercellular communications
What are the differences between the nervous system and the endocrine system?
- Messages - NS (uses action potentials and neurotransmitters) ES (hormones)
- Message speed and duration - NS (fast and short) ES (slow and long)
What are the major endocrine glands?
- Pituitary glands
- Thyroid glands
- Parathyroid glands
- Adrenal glands
- Pineal glands
What are other organs/ tissues that have endocrine cells?
- hypothalamus
- thymus
- pancreas
- ovaries/ testes
- kidneys, liver, stomach, heart, skin, and adipose tissue
Function of endocrine glands
Secrete products into interstitial fluid which diffuse into blood INSIDE BODY
Function of exocrine glands
Secrete products into ducts or lumens or to the OUTSIDE BODY
What are the two types of hormones?
- Local hormones
- Circulating hormones
How are local hormones secreted?
Through PARACRINE cells and AUTOCRINE cells
What does a Paracrine cell do?
Releases local hormones to a paracrine receptor on a nearby target cell
What does an autocrine cell do?
Releases local hormones to attach to the autocrine receptor on the same autocrine cell
What are 2 examples of local hormones?
- IL-2 (released from Th* cell to stimulate proliferation of Th* cell and activated cytotoxic T cells)
- Histamine (stimulates HCl secretion from parietal cells in stomach)
What do circulating hormones do?
Enter interstitial fluid from an endocrine cell, enter bloodstream, then go to a hormone receptor on a distant target cell
What are the two types of circulatory hormones?
- Lipid soluble hormones
- Water soluble hormones
What is a lipid soluble hormone?
a hormone bound to transport proteins for transport in body fluids
What is a water soluble hormone?
a hormone that freely dissolve in body fluids
What are the two types of lipid soluble hormones?
Steroid hormones and thyroid hormones
What are steroid hormones? Label some
A hormone derived from cholesterol
ex: aldosterone, cortisol, testosterone, estrogen, progesterone
What are the two types of water soluble hormones?
- Peptide and protein hormones
- Biogenic amines
What are peptide and protein hormones? Label some
- chains of amino acids
ex: ADH, hGH, TSH, ACTH, insulin, glucose, EPO
What are biogenic amines? Label some
- modified amino acids
ex: NE, epinephrine, histamine, melatonin
What are some organ functions that hormones regulate?
- metabolic pathways
- biological clock
- immune functions
- reproduction
- growth and development
What must target cells have to receive info from hormones?
Receptors
Where can receptors be found on target cells?
Inside the cell or on the cell surface
How do cells change bc of hormones?
- starts synthesis of new molecules
- changes membrane permeability
- alters rate of reaction
True or false: Do different target cells response to the same hormone in the same way?
False
Where are steroid hormone receptors found in target cells?
Inside the target cell
What do steroid hormones do?
Changes levels of specific gene expressions
*target cells respond very slowly
Where are peptide hormone receptors?
Surface of target cell
What do peptide hormones do?
- stimulates a receptor which stimulates a SECOND MESSENGER which adds/removes phosphorus to proteins (ex: ADP -> ATP)
Do target cells respond to water soluble hormones slow or fast?
FAST
How can hormones (1st messengers) effect the levels of second messengers?
Increase or decrease levels
What are some examples of second messengers?
cAMP
Calcium ions
cGMP
True or False: The same hormone can use different second messengers in different target cells
True
What processes do second messengers usually involve?
phosphorlyation or dephosphorylation
How does a hormone cause one type of response in one target cell and a different response in another target cell?
Different types of receptors generate different second messengers
What are two hormones that use the cAMP and Phospholipase C second messenger systems?
Angiotensin II and Vasopressin
