Endocrine System Part 1 Flashcards
what is the ENDOCRINE SYSTEM? what is its main FUNCTION?
ENDOCRINE SYSTEM:
refers to the COLLECTION of GLANDS in an organism – use of SECRETION OF HORMONES into the CIRCULATORY SYSTEM to other TARGET ORGANS
definition of ENDOCRINOLOGY
the STUDY OF HORMONES and ENDOCRINE ORGANS
how does the NERVOUS SYSTEM and ENDOCRIME SYSTEM WORK together? how do they DIFFER?
known as the NEUROENDOCRINE SYSTEM:
SHARED CHARACTERISTICS–
- both share MANY CHEMICAL MESSENGERS
- both share specific BINDING to SPECIFIC RECEPTORS
- both regulated primarily by NEGATIVE FEEDBACK MECHANISMS
- END GOAL: PRESERVING HOMEOSTASIS
NERVOUS SYSTEM:
- use of specific NEUROTRANSMITTERS
- FASTER ONSET of ACTION
- TARGET CELLS: muscle cells + other neurons
ENDOCRINE SYSTEM:
- use of specific HORMONES
- SLOWER ONSET of ACTION
- TARGET CELLS: cells throughout body
what are the TYPES OF GLANDS found within the ENDOCRINE SYSTEM?
EXOCRINE GLANDS
- seen in NONHORMONAL SUBSTANCES
ex. sweat and saliva
- have DUCTS–carry SECRETION to MEMBRANE SURFACE
ENDOCRINE GLANDS
- produces HORMONES
- DOES NOT HAVE DUCTS
what are OUR ENDOCRINE GLANDS (5)? what is our NEUROENDOCRINE ORGAN?
Are there any specific organs that have BOTH EXOCRINE AND ENDOCRINE FUNCTIONS?
ENDOCRINE GLANDS:
- PITUITARY
- THYROID
- PARATHYROID
- ADRENAL
- PINEAL
NEUROENDOCRINE ORGAN:
- HYPOTHALAMUS
BOTH (ENDOCRINE + EXOCRINE):
- PANCREAS
- GONADS
- PLACENTA
describe the specific CHEMICAL MESSENGERS we find within the ENDOCRINE SYSTEM.
HORMONES:
- creation of LONG DISTANCE CHEMICAL SIGNALS; often traveling within the BLOOD OR LYMPH
- work through a LOCK AND KEY mechanism
AUTOCRINES:
- chemicals that exert the EFFECTS on the SAME CELLS that secrete them
PARACRINES:
- LOCALLY ACTING chemicals that affect cells OTHER THAN THOSE that secrete them
*AUTOCRINES + PARACRINES are NOT CONSIDERED PART of the ENDOCRINE SYSTEM–they are just LOCAL CHEMICAL MESSENGERS
what is a HORMONE?
HORMONE CHARACTERISTICS
chemical that is secreted by SPECIFIC ENDOCRINE CELLS
- bind to SPECIFIC RECEPTORS
- again, work through targeting FAR AWAY ORGANS + CELLS
- function at VERY LOW CONCENTRATIONS
describe HORMONE ACTIVITY–how are they REGULATED?
HORMONE ACTIVITY:
- hormones can only affect TARGET CELLS that possess specific PROTEIN RECEPTORS
RECEPTORS:
- constantly being SYNTHESIZED and BROKEN DOWN
- DOWN-REGULATION:
seen in HIGH CONCENTRATIONS of
HORMONE (less sensitivity to hormone)
- **UP-REGULATION:
seen in LOW CONCENTRATIONS of
HORMONE (more sensitivity to hormone)
-describe the HORMONAL CHEMICAL STRUCTURE–what are the TWO TYPES OF HORMONES?
HORMONES:
- acts depending on specific CHEMICAL NATURE & RECEPTOR LOCATION
AMINO ACID-BASED HORMONES
contains AMINO ACID DERIVATIVES + PEPTIDE + PROTEINS
- acts specifically on PLASMA MEMBRANE RECEPTORS
- act through G PROTEIN in SECOND MESSENGER SYSTEMS
- CANNOT enter cell directly
LIPID-SOLUBLE HORMONES
contains GONADOL + ADRENOCORTICAL HORMONES (STEROID HORMONES)
- synthesized from CHOLESTEROL
- acts on INTRACELLULAR RECEPTORS–directly activates GENES
- CAN ENTER CELL DIRECTLY
what are our WATER-SOLUBLE HORMONES/AMINO ACID BASED HORMONES?
WHERE ARE THEY FOUND??????
WATER-SOLUBLE HORMONES/AMINO ACID BASED HORMONES
(AMINES) CATECHOLAMINES
- epinephrine
- norepinephrine
- dopamine
(ADRENAL MEDULLA)
(AMINES) OTHERS
- melatonin (PINEAL GLAND)
- histamine (MAST CELLS–connective tissue)
- serotonin (BLOOD PLATELETS)
PEPTIDE & PROTEIN HORMONES
- hypothalamic releasing & inhibiting (HYPOTHALAMUS)
- posterior pituitary hormones (2)
- anterior pituitary hormones (7)
- pancreatic hormones (3)
- stomach and SI hormones–enteroendocrine cells)
- parathyroid hormone (PARATHYROID GLAND)
- erythropoietin (KIDNEYS)
- leptin (ADIPOSE TISSUE)
ELCOSANOIDS
- prostaglandins + leukotrienes (in ALL CELLS except RBC)
what are our POSTERIOR PITUITARY HORMONES (2)?
- oxytocin
- antidiuretic hormone
what are our ANTERIOR PITUITARY HORMONES (7)? what’s so SPECIAL ABOUT THEM?
- HUMAN GROWTH HORMONE
- THYROID STIMULATING HORMONE (TSH)
- ADRENOCORTICOTROPIC HORMONE (ACH)
- FOLLICLE STIMULATING HORMONE (FSH)
- LUTEINIZING HORMONE (LH)
- PROLACTIN
- MELANOCYTE STIMULATING HORMONE
PEPTIDE HORMONE CHARACTERISTICS:
- MAIN HORMONES of body
- synthesized as PROHORMONES–they are INACTIVE PRECURSOR MOLECULES (conversion into active form)
- come from short polypeptide chains of amino acids
- have some GLYCOPROTEINS
what are our PANCREATIC HORMONES (4)?
- INSULIN
- GLUCAGON
- SOMATOSTATIN
- PANCREATIC POLYPEPTIDE
what are our LIPID-SOLUBLE HORMONES?
where are they FOUND?
STEROID HORMONES
- **adrenal cortex hormones* (3)
- calcitriol (KIDNEYS)
- testosterone (TESTES)
- estrogens, progesterone (OVARIES)
THYROID HORMONES
quite COMPLEX–structured as an AMINO-BASED HORMONE, but WORKS AS A LIPID-SOLUBLE (CAN ENTER CELL DIRECTLY)
- T3 (triiodothyronine) & T4 (thyroxine)
(THYROID GLAND–FOLLICULAR CELLS)
GAS
- nitric oxide (NO)
(ENDOTHELIAL CELLS–BV)
what are our ADRENAL CORTEX HORMONES/CORTICOSTEROIDS?
what’s so SPECIAL ABOUT STEROID HORMONES?
- aldosterone
- cortisol
- androgens
STEROID HORMONES:
- bound to SPECIFIC TRANSPORT PROTEINS
- LONGER CIRCULATION vs. PEPTIDE HORMONES
how do AMINO-ACID DERIVATIVES EXERT their EFFECTS?
through SECOND-MEMBRANE SYSTEMS
MAIN SYSTEMS:
- CYCLIC AMP
- PIP2-CALCIUM
describe briefly the process of cAMP
cAMP:
- a use of INTRACELLULAR SIGNAL TRANSDUCTION
PATHWAY:
- hormone creates a “CASCADE”–creation of SPECIFIC RESPONSE IN the CELL
- the CHANGING of TRANSMEMBRANE PROTEIN–linkages to G PROTEINS
G PROTEINS
transmits signals from inside and outside + activates enzyme ADENYLATE CYCLASE
ADENYLATE CYCLASE
- conversion of ATP to cAMP
cAMP
- activates PROTEIN KINASE–changes proteins with the addition of PHOSPHATE, which helps ACTIVATE DEPOLARIZATION OF CELL–ACTIVATING 2nd-MESSENGER SYS
describe briefly the process of PIP-2-Calcium
PIP2-CALCIUM:
- SPECIFIC EFFECTOR ENZYME
- creation of TWO SECOND MESSENGERS
DAG
- activates PROTEIN KINASE
IP3
- activation of SMOOTH ER for CALCIUM RELEASE
CALCIUM
activiates the G PROTEIN–similar process from there to cAMP
how do LIPID-SOLUBLE HORMONES EXERT their EFFECTS?
use of DIRECT GENE ACTIVATION
- has RECEPTOR HORMONE COMPLEXES that begin to enter the cell–BIND DIRECTLY to DNA
DNA:
- initiation of TRANSCRIPTION of GENE to mRNA
mRNA:
protein synthesis
describe HORMONE RELEASE.
what TRIGGERS HORMONE RELEASE?
NEGATIVE FEEDBACK SYSTEM
- the increased hormone effects on actual target organs can inhibit hormone release
- seen within only a narrow and desirable range
TRIGGERS
- ENDOCRINE GLAND STIMULI
the STIMULATION of the ENDOCRINE GLAND
- NERVOUS SYSTEM MODULATION
the STIMULATION of the NERVOUS SYSTEM
do any hormones operate through POSITIVE FEEDBACK?
yes, OXYTOCIN + PROLACTIN
OXYTOCIN
- the INTIMACY HORMONE
- greater CONTRACTIONS during birth–greater STRETCH OF UTERUS
- the EJECTION OF MILK
PROLACTIN
- the PRODUCTION OF MILK
how is HORMONE SECRETION REGULATED?
- secretion is seen in SHORT BURSTS
REGULATION
- SIGNALS from the NERVOUS SYSTEM
- CHEMICAL CHANGES within BLOOD
- OTHER HORMONES
what are the types of ENDOCRINE GLAND STIMULI?
THREE TYPES:
- HUMORAL STIMULI
- NEURAL STIMULI
- HORMONAL STIMULI
describe HUMORAL STIMULI
HUMORAL STIMULI
- the changing of BLOOD LEVELS OF IONS and NUTRIENTS that directly stimulate SECRETION OF HORMONES
EXAMPLE:
- DECLINING BLOOD CALCIUM–stimulation of PARATHYROID GLANDS for secretion PTH (INCREASES BLOOD CALCIUM)
describe NEURAL STIMULI
NEURAL STIMULI
- where NERVE FIBERS stimulate HORMONE RELEASE
EXAMPLE:
- SYMPATHETIC NERVOUS FIBERS–stimulation of ADRENAL MEDULLA to SECRETE CATECHOLAMINES
describe HORMONAL STIMULI
HORMONAL STIMULI
- the STIMULATION of other ENDOCRINE ORGANS to release THEIR HORMONEs
EXAMPLES:
- HYPOTHALAMIC HORMONES–stimulation of ANTERIOR PITUITARY HORMONES
- APH–stimulation of TARGET HORMONES to stimulate OTHER ENDOCRINE GLANDS
briefly describe NERVOUS SYSTEM MODULATION
NERVOUS SYSTEM
- can make specific ADJUSTMENTS
- modification of either STIMULATION or INHIBITION of ENDOCRINE GLANDS
- can even OVERRIDE NORMAL ENDOCRINE CONTROLS
EXAMPLE:
overriding hormone INSULIN in times of SEVERE STRESS–to make BLOOD GLUCOSE LEVELS RISE
describe TARGET CELL SPECIFICITY and what factors ACTIVATE TARGET CELLS?
TARGET CELL SPECIFICITY:
- the need for SPECIFIC RECEPTORS where the HORMONE BINDS
TARGET CELL ACTIVATION
1. BLOOD LEVELS of HORMONE
2. the RELATIVE NUMBER OF RECEPTORS on/in the target cell
3. the AFFINITY (STRENGTH) of BINDING between the RECEPTOR + HORMONE
what is HALF-LIFE and what dictates the CONCENTRATION of CIRCULATING HORMONES?
HALF-LIFE
the time required for specific levels of hormones in the blood to DECREASE BY HALF ITS LEVEL
CONCENTRATION OF CIRCULATING HORMONE
- RATE OF RELEASE
- SPEED OF INACTIVATION and REMOVAL
what are the THREE INTERACTIONS of HORMONES at TARGET CELLS?
PERMISSIVENESS
SYNERGISM
ANTAGONISM
