Chemical Classes Of Hormones, Peptide Secretion

Front 1

Define: Neurotransmitters

Back 1

Neurotransmitters are released by axon terminals of neurons into the synaptic junctions and act locally to central nerve function

Front 2

Define: Endocrine Hormones

Back 2

Endocrine hormones are released by glands or specialized cells into the circulating blood and influence the functions of target cells at another location in the body

Front 3

Define: Neuroendrocrine hormones

Back 3

Neuroendrocrine hormones are secreted by neurons into circulating blood and influence the function of target cells at another location of body

Front 4

Define: paracrines

Back 4

Paracrines are secreted by cells into the extracellular fluid and effect the function of the same cells that produced them

Front 5

Define: Autocrines

Back 5

Autocrines are secreted by cells into the extracellular fluid and effect the function of the same cells that produced them

Front 6

Define: Cytokines

Back 6

Cytokines are peptides secreted by cells into the extracellular fluid and can function as autocrines, paracrines, or endocrine hormones

Front 7

Name the three general classes of hormones

Back 7

Proteins & polypeptides
Steroids
Derivatives of the amino acid tyrosine

Front 8

Where are Proteins and Polypeptides secreted?

Back 8

Protein and polypeptide includes hormones secreted by the anterior and posterior pituitary gland, the pancreas, the parathyroid gland, and many others.

Front 9

Where are steroids secreted?

Back 9

Steroids are secreted by the adrenal cortex, the ovaries, and the placenta

Front 10

Where are derivatives of the amino acid tyrosine secreted?

Back 10

Derivatives of the amino acid tyrosine are secreted by the thyroid and the adrenal medulla. There are no known polysaccharides or nucleic acid hormones

Front 11

Where are protein and peptide hormones synthesized?

Back 11

Rough end of the Endoplasmic Reticulum

Front 12

What are the steps of protein and peptide hormone synthesis?

Back 12

1) Prehormones are cleaved to form prohormones in the ER.
2) Prohormones are transferred to Golgi for packaging into secretory Vesicles. Enzymes inside vesicle cleave prohormones to produce biologically active hormones.
3) Stored in cytoplasm until secretion is needed

Front 13

When does secretion of proteins and peptides occur?

Back 13

Secretion occurs when Secretory Vesicles fuse with cell membrane and granular contents are extruded into interstitial fluid or directly into the blood stream by exocytosis

Front 14

What stimulates exocytosis?

Back 14

Stimulus for exocytosis is an increase in cytosolic Ca+ concentration caused by depolarization of the plasma membrane OR stimulus of endocrine cell surface receptors causing an increase in cAMP & activation of protein kinases

Front 15

Steroid hormones are usually synthesized from Cholesterol and are not stored, where do they go?

Back 15

Steroids are lipid soluble. Once steroids are synthesized they diffuse across the cell membrane and enter interstitial fluid then the blood stream.

Front 16

Amine Hormones are derived from what?

Back 16

Amine hormones are derived from Tyrosine.

Front 17

What are the two amine hormone groups?

Back 17

Thyroid and Adrenal Medullary

Front 18

Where are thyroid hormones synthesized and stored?

Back 18

Thyroid hormones are synthesized and stored in the thyroid gland and incorporated into macromolecules of the protein thyroglobolin which is stored in large follicles within the thyroid gland

Front 19

What is Luteinizing hormone (LH)?

Back 19

Surge of hormones as a result of stimulatory effect of estrogen on the anterior pituitary before ovulation. Secretion of LH then acts on ovaries to stimulate additional secretion of estrogen, which causes more secretion of LH. Once appropriate level is reached, negative feedback control of hormone secretion is then exerted.

Front 20

How are water-soluble hormones transported?

Back 20

Water-soluble hormones are dissolved in the plasma and transported from their sites of synthesis to target tissues, where they diffuse out of the capillaries, into interstitial fluid, and ultimately to target cells.

Front 21

Steroid and thyroid hormones circulate in the blood mainly bound to what?

Back 21

plasma proteins