Chapter 16-Endocrine System Flashcards
Mechanisms for Intercellular Communication
Direct communication Paracrine Communication Autocrine communication Endocrine communication Sympathetic communication
Explain direct communication
Transmitted through gap junctions
Chemical signals are ions, lipid-soluble
Distributed to adjacent cells via connexons
Explain paracrine communication
Transmitted via extra cellular fluid
Chemical signal are paracrines
Limited to local area and cells with proper receptors
Explain autocrine communication
Transmitted via extra cellular fluid
Chemical signals are autocrines
Distributed to the cell that actually secretes the chemical signal
Explain endocrine communication
Transmitted via bloodstream
Chemical signal : hormones
Distributed to target cells with proper receptors
Explain sympathetic communication
Transmitted via neurotransmitters across synapses
Distributed to very specific area with proper receptors.
How are the endocrine and nervous systems similar?
Both release chemicals to bind to receptors on target cells.
They share common chemical messengers (like E and NE)
Both mainly use negative feedback
Both want to preserve homeostasis by regulating activities of other cells organs tissues and systems
What are the three chemical structures of hormones?
Acid derivatives
Peptide hormones
Lipid derivatives
What group of hormones are considered acid derivatives? Give an example of each.
Thyroid hormones (T4) Catecholamines (E) Tryptophan derivatives (Melatonin)
Explain peptide hormones
Synthesized as prohormones
Short polypeptide chains of amino acids (like ADH) to small peptones like insulin.
What is a pro hormone
Inactive precursor molecules that are converted to active hormones
What organs or glands secrete polypeptide hormones?
Hypothalamus Thymus Heart Digestive Tract Pancreas Pituitary Glans
Glycoproteins are considered peptide hormones. Describe them and give examples.
They are polypeptides with carb side chains that function as hormones.
Examples: TSH, LH, FSH
Explain lipid derivatives
Carbon rings and side chains built either from eicosanoids (fatty acids) or cholesterol (sterilize hormones
Eicosanoids
Paracrines that coordinate cellular activities and affect Enzymatic processes
Leukotriens
An eicosanoid that has a secondary role as a hormone
Prostaglandins
A second group of eicosanoids involved in coordinating local cellular activities. (Proglandin E)
What organs release Steroid Hormones?
Reproductive organs
Cortex of adrenal glands
Kidneys
What steroid hormone do reproductive organs release?
Androgens (male)
Estrogen and progesterone (female)
What steroid hormone does the cortex of the adrenal gland release?
Corticosteroids
What steroid does the kidneys release?
Calcitriol
Why do steroids remain in circulation longer than secreted peptide hormones?
Because steroids are bound to specific transport proteins in blood.
What is the endocrine system
Organs whose primary function is the production of hormones or paracrines