Endocrine System Flashcards
Endocrine Communication
- Cell releases chemical message (hormone) into bloodstream
- Affects activity of specific target cells in the body
Paracrine Communication
- Cell releases chemical message (paracrine) into extracellular fluid
- Transfer information from cell to cell
Hormone
- Alter function of target cell by changing types, quantities and activities of enzymes/structural proteins
- Slow/long lasting
Synaptic Communication
- Neuron releases a neurotransmitter (chemical message) across a synapse
- Rapid and short lasting
Autocrine Communication
Chemical message (autocrine) affect same cell that secretes them
Direct Communication
- Occurs between 2 cells of the same type
- Must be in direct physical contact
Major organs of Endocrine System
- Pituitary gland
- Thyroid gland
- Pancreas
- Adrenal gland
- Endocrine tissues in other systems
Function of Endocrine System
- Directs long-term changes in activities of organ systems
- Adjusts metabolic activities in body
- Control many structural and functional changes; achieved by release of hormones or paracrines
Amino Acid Derivatives
-Small molecules structurally relate to amino acids
Lipid Derivatives
- Produces either eicosacnoids or steroid hormones
- Secreted by endocrine cells
Peptide Hormones
- Chains of amino acids
- Short polypeptides/small proteins
Glands
- Collection of cells that produce secretions
- Endocrine Glands: secrete into fluid between cell
- Exocrine Glands: secrete into passageways
Lipophilic Hormones
- Bind to intracellular receptors: “love lipids”
- Can directly pass through plasma membrane
Binding of Lipophilic Hormones to its receptor modifies activity of the target cell by…
Altering genetic activity
Binding of Hydrophilic Hormones to its receptor modifies activity of the target cell by…
- Altering permeability of plasma membrane
- Altering rate of synthesis of proteins/enzymes
Hydrophilic Hormones
- Bind to receptor on plasma membrane: “love water”
- Can’t directly pass through plasma membrane
Describe the two ways that these hormones can circulate in the blood.
- Hormones circulate in plasma part of the blood
- It can either be free (active) or bound (inactive) to plasma proteins
G-Proteins
- When there is no binding between hormone and receptor, the G protein is inactive
- When hormone binds to receptor, it activates G-Proteins
- The activated G protein leads to the appearance of the second messenger
First Messenger
Hormone bind to receptor on plasma membrane
Second Messenger
Intermediary molecule that appears due to hormone binding to receptor on plasma membrane
Signal Amplifcation
Magnifies effect of hormone on target cell
Factors that affect plasma concentration of freely circulating hormone
1) Extent of binding to plasma proteins
2) Extent of binding to target cell
3) Rate of removal from blood by metabolic inactivation and excretion
4) Rate of hormone secretion by endocrine cells
Hypothalamus
- Integrates activities of nervous and endocrine system
- Neurons releasing 2 hormones via posterior pituitary gland
- Secretes regulatory hormones that control endocrine cells in anterior pituitary gland
- Exerts neural control over endocrine cells in adrenal gland
Pituitary Gland
Anterior Lobe: releases 7 hormones produced by endocrine cells in pituitary glands
Posterior Lobe: releases 2 hormones produced by neurons in hypothalamus
