Endocrine System Part 1 Flashcards

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1
Q

what is the ENDOCRINE SYSTEM? what is its main FUNCTION?

A

ENDOCRINE SYSTEM:

refers to the COLLECTION of GLANDS in an organism – use of SECRETION OF HORMONES into the CIRCULATORY SYSTEM to other TARGET ORGANS

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2
Q

definition of ENDOCRINOLOGY

A

the STUDY OF HORMONES and ENDOCRINE ORGANS

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3
Q

how does the NERVOUS SYSTEM and ENDOCRIME SYSTEM WORK together? how do they DIFFER?

A

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

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4
Q

what are the TYPES OF GLANDS found within the ENDOCRINE SYSTEM?

A

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

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5
Q

what are OUR ENDOCRINE GLANDS (5)? what is our NEUROENDOCRINE ORGAN?

Are there any specific organs that have BOTH EXOCRINE AND ENDOCRINE FUNCTIONS?

A

ENDOCRINE GLANDS:
- PITUITARY
- THYROID
- PARATHYROID
- ADRENAL
- PINEAL

NEUROENDOCRINE ORGAN:
- HYPOTHALAMUS

BOTH (ENDOCRINE + EXOCRINE):
- PANCREAS
- GONADS
- PLACENTA

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6
Q

describe the specific CHEMICAL MESSENGERS we find within the ENDOCRINE SYSTEM.

A

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

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7
Q

what is a HORMONE?

A

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

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8
Q

describe HORMONE ACTIVITY–how are they REGULATED?

A

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)

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9
Q

-describe the HORMONAL CHEMICAL STRUCTURE–what are the TWO TYPES OF HORMONES?

A

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

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10
Q

what are our WATER-SOLUBLE HORMONES/AMINO ACID BASED HORMONES?

WHERE ARE THEY FOUND??????

A

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)

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11
Q

what are our POSTERIOR PITUITARY HORMONES (2)?

A
  • oxytocin
  • antidiuretic hormone
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12
Q

what are our ANTERIOR PITUITARY HORMONES (7)? what’s so SPECIAL ABOUT THEM?

A
  • 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

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13
Q

what are our PANCREATIC HORMONES (4)?

A
  • INSULIN
  • GLUCAGON
  • SOMATOSTATIN
  • PANCREATIC POLYPEPTIDE
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14
Q

what are our LIPID-SOLUBLE HORMONES?

where are they FOUND?

A

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)

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15
Q

what are our ADRENAL CORTEX HORMONES/CORTICOSTEROIDS?

what’s so SPECIAL ABOUT STEROID HORMONES?

A
  • aldosterone
  • cortisol
  • androgens

STEROID HORMONES:
- bound to SPECIFIC TRANSPORT PROTEINS
- LONGER CIRCULATION vs. PEPTIDE HORMONES

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16
Q

how do AMINO-ACID DERIVATIVES EXERT their EFFECTS?

A

through SECOND-MEMBRANE SYSTEMS

MAIN SYSTEMS:
- CYCLIC AMP
- PIP2-CALCIUM

17
Q

describe briefly the process of cAMP

A

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

18
Q

describe briefly the process of PIP-2-Calcium

A

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

19
Q

how do LIPID-SOLUBLE HORMONES EXERT their EFFECTS?

A

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

20
Q

describe HORMONE RELEASE.

what TRIGGERS HORMONE RELEASE?

A

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

21
Q

do any hormones operate through POSITIVE FEEDBACK?

A

yes, OXYTOCIN + PROLACTIN

OXYTOCIN
- the INTIMACY HORMONE
- greater CONTRACTIONS during birth–greater STRETCH OF UTERUS
- the EJECTION OF MILK

PROLACTIN
- the PRODUCTION OF MILK

22
Q

how is HORMONE SECRETION REGULATED?

A
  • secretion is seen in SHORT BURSTS

REGULATION
- SIGNALS from the NERVOUS SYSTEM
- CHEMICAL CHANGES within BLOOD
- OTHER HORMONES

23
Q

what are the types of ENDOCRINE GLAND STIMULI?

A

THREE TYPES:
- HUMORAL STIMULI
- NEURAL STIMULI
- HORMONAL STIMULI

24
Q

describe HUMORAL STIMULI

A

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)

25
Q

describe NEURAL STIMULI

A

NEURAL STIMULI
- where NERVE FIBERS stimulate HORMONE RELEASE

EXAMPLE:
- SYMPATHETIC NERVOUS FIBERS–stimulation of ADRENAL MEDULLA to SECRETE CATECHOLAMINES

26
Q

describe HORMONAL STIMULI

A

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

27
Q

briefly describe NERVOUS SYSTEM MODULATION

A

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

28
Q

describe TARGET CELL SPECIFICITY and what factors ACTIVATE TARGET CELLS?

A

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

29
Q

what is HALF-LIFE and what dictates the CONCENTRATION of CIRCULATING HORMONES?

A

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

30
Q

what are the THREE INTERACTIONS of HORMONES at TARGET CELLS?

A

PERMISSIVENESS
SYNERGISM
ANTAGONISM