3A: Structure and functions of the nervous and endocrine systems and ways in which these systems coordinate the organ systems Flashcards Preview

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Flashcards in 3A: Structure and functions of the nervous and endocrine systems and ways in which these systems coordinate the organ systems Deck (170):
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Neurons

Highly specialized cells responsible for the conduction of impulses

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How do neurons communicate?

Occur through electrical and chemical forms of communication

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Electrical Communication

Occurs via ion exchange and generation of membrane potentials down the length of the axon

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Electrical Communication

Occurs via ion exchange and generation of membrane potentials down the length of the axon

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Chemical Communication

Occurs via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell

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Chemical Communication

Occurs via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell

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Dendrites

Appendages that receive signals from other cells

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Dendrites

Appendages of the cell body that receive signals from other cells

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Cell Body/Soma

Location of the nucleus and organelles such as ER and Ribosomes

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Axon

Long appendage down which an AP travels

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Axon Hillock

Where the cell body transitions to the axon and where AP are initiated

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Axon Hillock

Where the cell body transitions to the axon and where AP are initiated

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Nerve Terminal/Synaptic Bouton

The end of the axon from which neurotransmitters are released

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Synapse

Consists of nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cell and the space between the two known as the synaptic cleft

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Synapse

Consists of nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cell and the space between the two known as the synaptic cleft

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Myelin

An insulating substance that prevents signal loss and dissipation of the impulse and crossing of neural impulses from adjacent neurons

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Oligodendrocytes

Creates myelin in the CNS

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Schwann Cells

Creates myelin in the PNS

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Schwann Cells

Creates myelin in the PNS

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Nerves or Tracts

Bundles of axons

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Tracts

Carry only one type of information

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Ganglia

Cell bodies of neurons of the same type within a nerve cluster in the PNS

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Nuclei

Cell bodies of individual neurons with a tract cluster in the CNS

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Nuclei

Cell bodies of individual neurons with a tract cluster in the CNS

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Neuroglia/Glial Cells

Astrocytes
Ependymal Cells
Microglial Cells

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Astrocytes

Nourish neurons and form the blood-brain barrier which controls the transmission of solutes from the bloodstream into nervous tissue

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Ependymal Cells

Line the ventricles of the brain and produce CSF

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CSF

Physically supports the brain and serves as a shock absorber

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CSF

Physically supports the brain and serves as a shock absorber

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Microglia

Phagocytic cells that ingest and break down waste products and pathogens in the CNS

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Microglia

Phagocytic cells that ingest and break down waste products and pathogens in the CNS

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Resting Membrane Potential

-70 mV

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What maintains the resting membrane potential?

Sodium-Potassium ATPase

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What maintains the resting membrane potential?

Sodium-Potassium ATPase

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Excitatory Signals [EPSPs]

Cause depolarization; Glu, ACh

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Inhibitory Signals [IPSPs]

Cause hyperpolarization; GABA

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Ionotropic Receptors

Ligand gated, allow K and Cl to hyperpolarize the membrane

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Metabotropic

Block Ca ions

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Metabotropic

Block Ca ions

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Threshold Potential

-55 mV

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Threshold Potential/Voltage

-55 mV

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Temporal Summation

Addition of multiple signals near each other in time

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Spatial Summation

Addition of multiple signals near each other in space

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What maintains the resting membrane potential?

Sodium-Potassium ATPase
K Leak Channels

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Spatial Summation

Addition of multiple signals near each other in space

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Action Potential Outline

Resting -> Depolarization -> Repolarization -> Hyperpolarization -> Refractory Period

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Resting Stage

-70 mV maintained by ATPase and Leak Channels

Lots of sodium outside and lots of potassium inside

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Depolarization

Voltage gated sodium channels open, sodium rushes in and membrane potential increases to +30 mV

Lots of sodium inside and lots of potassium inside

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Depolarization

Voltage gated sodium channels open, sodium rushes in and membrane potential increases to +30 mV

Lots of sodium inside and lots of potassium inside

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Repolarization

Potassium channels open and sodium channels inactivate, potassium rushes outside and membrane potential drops

Lots of sodium inside and lots of potassium outside

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Repolarization

Potassium channels open and sodium channels inactivate, potassium rushes outside and membrane potential drops

Lots of sodium inside and lots of potassium outside

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Hyperpolarization

Potassium channels close but due to the timing the membrane potential briefly drops below the resting potential to around -90 mV

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Hyperpolarization

Potassium channels close but due to the timing the membrane potential briefly drops below the resting potential to around -90 mV

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Refractory Period

Na/K ATPase works to reestablish the original resting state (more K inside and Na outside); neuron cannot general another action potential during this time

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Absolute Refractory Period

Depolarization to original resting state

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Relative Refractory Peroid

After hyperpolarization til the resting state; AP can fire if the stimuli is strong enough

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Relative Refractory Peroid

After hyperpolarization til the resting state; AP can fire if the stimuli is strong enough

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All-or-None Principle

The neuron will either respond completely or not at all to the stimuli

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All-or-None Principle

The neuron will either respond completely or not at all to the stimuli

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Neurotransmitter Breakdown

Done enzymatically or absorbed via reuptake channel or diffused out of the synaptic cleft

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Types of Neurons

Motor (Efferent)
Interneurons
Sensory (Afferent)

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CNS

Brain & Spinal Cord

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White Matter

Consists of myelinated axons

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Grey Matter

Consists of unmyelinated cell bodies and dendrites

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Location of Matter in the Brain

White matter is deeper than grey matter

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Location of Matter in the Spinal Cord

Grey matter is deeper than white matter

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Location of Matter in the Spinal Cord

Grey matter is deeper than white matter

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PNS Divisions

Somatic [Voluntary]
Autonomic [Involuntary]

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Autonomic Nervous System

Parasympathetic [Rest & Digest]
Sympathetic [Fight-or-Flight]

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Autonomic Nervous System

Parasympathetic [Rest & Digest]
Sympathetic [Fight-or-Flight]

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Reflex Arcs

Use the ability of interneurons in the spinal cord to relay information to the source of stimuli while simultaneously routing it to the brain

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Reflex Arcs

Use the ability of interneurons in the spinal cord to relay information to the source of stimuli while simultaneously routing it to the brain

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Monosynaptic Reflex Arc

Presynaptic Sensory Neuron fires directly onto the Postsynaptic Motor Neuron

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Polysynaptic Reflex Arc

Sensory neuron fires onto a motor neuron as well as interneurons that fire onto other motor neurons

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Major Functions of Nervous System

High level control, integration of body systems, adaptive capability to external influences, integrative and cognitive abilities

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Major Functions of Nervous System

High level control, integration of body systems, adaptive capability to external influences, integrative and cognitive abilities

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CNS, Forebrain Structures

Telencephalon, Diencephalon

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Telencephalon Structures

Cerebral Cortex, Basal Ganglia, Hippocampus, Amygdala

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Diencephalon Structures

Thalamus, Hypothalamus

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CNS, Midbrain Structures

Mesencephalon

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Mesencephalon Structures

Tectum, Cerebellum

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CNS, Hindbrain Structures

Metencephalon, Myelencephalon

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Metencephalon Structures

Pons, Cerebellum

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Myelencephalon Structures

Medulla

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Myelencephalon Structures

Medulla

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Sensory Neurons

Transmit sensory information, carries sensory input from the outside to the CNS

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Effector Neurons

Cause an effect, transmit motor signals from CNS to an effector organic to respond to physiologically to external stimuli

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Effector Neurons

Cause an effect, transmit motor signals from CNS to an effector organic to respond to physiologically to external stimuli

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Antagonistic Control of SNS and PSNS

They have opposing effects on the internal organs they innervate

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Sympathetic Function

Increases HR, BP
Increase Blood Flow to Muscle
Pupillary Dilation
Decrease Blood Flow to Digestive System
Increases Glycolysis and Glycogenolysis

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Parasympathetic Function

Decreases HR, BP
Decreases Blood Flow to Muscle
Pupillary Constriction
Increase Blood Flow to Digestive System
Increases Glycogenesis

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Supraspinal Circuits

Involves input from the brain or brainstem to process a stimuli, unlike most reflex arcs

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Supraspinal Circuits

Involves input from the brain or brainstem to process a stimuli, unlike most reflex arcs

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Voltage-Gated Channels

Group of transmembrane ion channel that open or close based on changes in the cells membrane potential; include sodium, calcium and potassium channels

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Ligand-Gated Channels

Group of transmembrane ion channel proteins that open when a specific ligand molecule binds to the receptor protein; the binding causes a confirmational change

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Receptor Enzymes
[Enzyme-Linked Receptors/Catalytic Receptors]

Extracellular ligand binds and activates intracellular enzymatic activity

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Types of Receptor Enzymes

Receptor Serine-Threonine Kinases
Receptor Tyrosine Kinases
Tyrosine-Kinase Associated Receptors

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Receptor Tyrosine Kinases

Kinase enzymes that specifically phosphorylate tyrosine amino acids; growth factor binds to the extracellular domain which eventually leads to the production of a second messenger cascade

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G-Protein Coupled Receptors

Large integral membrane proteins; its ligand is usually cAMP, peptides or large proteins

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G-Protein Coupled Receptors

Large integral membrane proteins; its ligand is usually cAMP, peptides or large proteins

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GPCR Outline

Ligand binds to an active receptor causing conformational change that activates the protein, transmits the extracellular signal to inside of the cell

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GPCR Outline

Ligand binds to an active receptor causing conformational change that activates the protein, transmits the extracellular signal to inside of the cell

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G Protein On vs. Off State

GTP = active
GDP = inactive

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G Protein On vs. Off State

GTP = active
GDP = inactive

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GPCR Activity

GDP binds to the alpha subunit and the GP Complex binds to nearby GPCR,

GTP replaces GDP and activates the receptors and the subunits dissociate causing activity

GTP is hydrolyzed back to GDP when it's no longer needed

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GPCR Activity

GDP binds to the alpha subunit and the GP Complex binds to nearby GPCR,

GTP replaces GDP and activates the receptors and the subunits dissociate causing activity

GTP is hydrolyzed back to GDP when it's no longer needed

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Endocrine Signaling

Involves the secretion of hormones directly into the bloodstream; travel to distant target tissues where they bind to receptors and induce a change

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Peptide Hormones

Composed of amino acids and are derived from large precursors that are cleaved during posttranslational modificaiton

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Peptide Hormones

Composed of amino acids and are derived from large precursors that are cleaved during posttranslational modificaiton

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Peptide Hormone Characteristics

Polar and cannot pass through the plasma membrane; bind to extracellular receptors where they trigger the transmission of a second messenger

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Peptide Hormones

Composed of amino acids and are derived from large precursors that are cleaved during posttranslational modification; travel freely through the bloodstream

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Peptide Hormone Characteristics

Polar and cannot pass through the plasma membrane; bind to extracellular receptors where they trigger the transmission of a second messenger; rapid onset but short-lived

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Steroid Hormones

Derived from cholesterol, they are minimally polar and can pass through the plasma membrane; cannot dissolve in the blood stream and must be carried by specific proteins

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Steroid Hormone Characteristics

Bind to intracellular or intranuclear receptors where they promote conformational change and bind to DNA, affecting the transcription of a particular gene; slow onset and are long-lived

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Steroid Hormone Characteristics

Bind to intracellular or intranuclear receptors where they promote conformational change and bind to DNA, affecting the transcription of a particular gene; slow onset and are long-lived

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Amino Acid-Derivative Hormones

Modified Amino Acids; share some features with peptide and steroid hormones; common examples are epinephrine, norepinephrine, T3 and T4

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Amino Acid-Derivative Hormones

Modified Amino Acids; share some features with peptide and steroid hormones; common examples are epinephrine, norepinephrine, T3 and T4

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Direct Hormones

Have effects on non-endocrine tissues

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Tropic Hormones

Have effects on other endocrine tissues

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Function of the Endocrine System

Regulate mood, growth, development, metabolism, sexual function and tissue function

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Function of the Endocrine System

Regulate mood, growth, development, metabolism, sexual function and tissue function

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Endocrine Glands

Hypothalamus, Pituitary Gland, Pineal Gland, Thyroid Gland, Parathyroid Gland, Adrenal Gland, Pancreas, Ovary, Testis

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Hypothalamus

Releases hormones that stimulate the anterior pituitary gland through paracrine release of hormones through the hypophyseal portal system

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Hypothalamic Hormones

GnRH, GHRH, TRH, CRF, PIF/Dopamine

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GnRH

Promotes release of FSH and LH

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GHRH

Promotes release of GH

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TRH

Promotes release of TSH

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CRF

Promotes release of ACTH

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PIF/Dopamine

Inhibits release of Prolactin

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PIF/Dopamine

Inhibits release of Prolactin

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Anterior Pituitary Hormones

FSH, LH, ACTH, TSH [Tropic] & Prolactin, Endorphins and GH [Direct]

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FSH

Promotes development of ovarian follicles in females and spermatogenesis in males

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LH

Promotes ovulation in females and testosterone production in males

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ACTH

Promotes synthesis and release of glucocorticoids (cortisol) from the adrenal cortex

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TSH

Promotes synthesis and release of T3 and T4

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Prolactin

Promotes milk production (letdown)

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Prolactin

Promotes milk production (letdown)

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Endorphins

Decrease perception of pain and cause euphoria

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Endorphins

Decrease perception of pain and cause euphoria

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GH

Promotes growth of bone and muscle and shunts glucose to these tissues; raises blood glucose concentrations

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GH

Promotes growth of bone and muscle and shunts glucose to these tissues; raises blood glucose concentrations

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Posterior Pituitary Hormones

ADH/Vasopressin, Oxytocin

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ADH/Vasopressin

Secreted in response to low blood volume or increased blood osmolarity and increases reabsorption of water in the collecting duct of the nephron, increase blood volume and decreasing blood osmolarity

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ADH/Vasopressin

Secreted in response to low blood volume or increased blood osmolarity and increases reabsorption of water in the collecting duct of the nephron, increase blood volume and decreasing blood osmolarity

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Oxytocin

Secreted during childbirth and promotes uterine contractions as well as milk letdown; regulated through positive feedback loop

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Thyroid Hormones

T3 and T4, Calcitonin

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T3 & T4

Produced by follicular cells and contain iodine; increase basal metabolic rate and alter the utilization of glucose and fatty acids

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Calcitonin

Produced by parafollicular cells, decreases plasma calcium concentration by promoting calcium excretion in the kidneys, decreasing calcium absorption in the gut and promoting calcium storage in bone

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Calcitonin

Produced by parafollicular cells, decreases plasma calcium concentration by promoting calcium excretion in the kidneys, decreasing calcium absorption in the gut and promoting calcium storage in bone

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Parathyroid Gland Hormones

PTH

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PTH

Increases blood calcium concentrations;

Decreases calcium by the kidneys;

Increase bone resorption directly to increase blood calcium concentrations

Activates vitamin D

Promotes resorption of phosphate from bone and reduces reabsorption

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PTH

Increases blood calcium concentrations;

Decreases calcium by the kidneys;

Increase bone resorption directly to increase blood calcium concentrations

Activates vitamin D

Promotes resorption of phosphate from bone and reduces reabsorption

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Adrenal Cortex Hormones

Glucocorticoids [Cortisol, Cortisone]
Mineralocorticoids [Aldosterone]
Cortical Sex Hormones [Androgens, Estrogens]

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Adrenal Cortex Hormones

Glucocorticoids [Cortisol, Cortisone]
Mineralocorticoids [Aldosterone]
Cortical Sex Hormones [Androgens, Estrogens]

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Cortisol/Cortisone

Increase blood glucose concentration, reduce protein synthesis, inhibit immune system, participate in the stress response; stimulated by ACTH

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Aldosterone

Promote sodium reabsorption in the distal convoluted tubule and collecting duct thus increasing water reabsorption; increases potassium and hydrogen ion excretion; regulated by RAAS

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Aldosterone

Promote sodium reabsorption in the distal convoluted tubule and collecting duct thus increasing water reabsorption; increases potassium and hydrogen ion excretion; regulated by RAAS

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Adrenal Medulla Hormones

Catecholamines [Epinephrine, Norepinephrine]

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Catecholamines

Promote glycogenolysis, increasing basal metabolic rate, heart rate, dilate bronchi and alter blood flow

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Catecholamines
[Epi, Norepi]

Promote glycogenolysis, increasing basal metabolic rate, heart rate, dilate bronchi and alter blood flow

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Catecholamines
[Epi, Norepi]

Promote glycogenolysis, increasing basal metabolic rate, heart rate, dilate bronchi and alter blood flow

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Pancreatic Hormones

Glucagon
Insulin
Somatostatin

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Pancreatic Hormones

Glucagon
Insulin
Somatostatin

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Glucagon
[Alpha Cells]

Raises blood glucose levels by stimulating protein and fat degradation, glycogenolysis and gluconeogenesis

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Insulin
[Beta Cells]

Lowers blood glucose levels by stimulating uptake by cells and anabolic processes like glycogenesis, fat and protein synthesis

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Insulin
[Beta Cells]

Lowers blood glucose levels by stimulating uptake by cells and anabolic processes like glycogenesis, fat and protein synthesis

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Somatostatin
[Delta Cells]

Inhibits insulin and glucagon secretion

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Somatostatin
[Delta Cells]

Inhibits insulin and glucagon secretion

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Pineal Gland Hormones

Melatonin

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Melatonin

Regulates circadian rhythms