Part 1 Flashcards
(27 cards)
Types of chemical receptors:
1 neurotransmitters 2 endocrine hormones 3 neuroendorcrine hormes 4 paracrines 5 autocrines 6 cytokines
Neurotransmitters
release by neurons axon criminals into synaptic junction
acts locally on the neuron functions
Endocrine Hormones
released by glands or specific cells into the circulating blood
acts on the targeted cell may be near or far
Neuroendocrine Hormones
released by the neuron into the circulation blood
acts on the targeted cell
Paracrine
Released by cells into the extracellular fluid
acts on neighboring different cell
Autocrines
released by cells into the extracellular fluid
acts on the cell that releases it binding into its own receptors
Cytokines
released by the cells into the extracellular fluid
acts as autocrines, paracrine, or even endocrine hormones.
ex IL hormone released by helper T cells
Function of the body chemical messengers
To control the body’s homeostasis
Endocrine hormones that affect different types of cells
Growth hormones released by anterior pituitary gland (causes growth in most parts of the body)
Thyroxine releases by thyroid gland (increase chemical reactions in most of the body cells)
Endocrine hormones that acts on a specific cell. why? examples?
Because that cell got its specific receptor for the hormone.
ACTH released by the anterior pituitary gland (stimulates the adrenal cortex, release the adernocortical hormone)
Ovarian Hormones released in females
(specific effect for the female genital organs and secondary characteristics for female organs)
Chemical Structure and synthesis of hormones
Polypeptides and peptides
Steriods
Derivatives of amino acid tyrosin
Polypeptide and peptide Hormones
Anterior and Posterior pituitary gland
Pancreas (insulin and glucagon)
Parathyroid Hormones
Steroid hormones
Adrenal cortex(Coristrol and aldosterone)
Ovarian (estrogen and proestrogen)
Testes(Testestrone)
Placenta
Derivatives of amino acids Tyrosin
Thyroid (Thyroxine) Adrenal Medulla (Epinephrine and norepinephrine )
Synthesis of polypeptide and peptide hormones
on the endoplasmic reticulum of a different endocrine cell
synthesized in as large biologically inactive proteins (pre-prohormones) and then cleaved into smaller (pro hormones ) in the endoplasmic reticulum, then transported into the Golgi apparatus to be packages as secretary vesicles. The enzymes found in the vesicles then cleaves the prohorme into biologically active hormones and inactive fragments
Polypeptide and peptide hormones storage
stored within the cytoplasm or bounded to the cell membrane until secreted by exocytosis
What increase the stimulus of exocytosis to hormones?
Cytoplasmic calcium caused by depolarisations of the plasma membrane
Steroid Characteristics
Lipid Soluble
consist of 3 cyclohexyl ring and 1 cyclophenyl ring
Steroid synthesis and storage
very little storage because they r highly lipid soluble which causes there diffusion thro the plasma membrane. It cells got a large storage of cholesterol ester in its cytoplasm in case of a stimulus to synthesis steroid hormones. Also cholesterol de novo synthesis is present.
formation of thyroid and adrenal medulla
By the action of enzymes in the cytoplasm of gobular cells
Thyroid hormones synthesis and storage
Synthesises and storage in the thyroid gland, in which incorporates with thyrogobulin which is stored in large follicles within the thyroid gland.
Secretion happens when amines are split from thyroglobulin and release the hormone into the blood in which it binds into plasma protein.
Epinephrine and Norepinephrine synthesis and storage
Synthesises in the adrenal medulla
produces more epinephrine than norepinephrine (4-1)
Stored in vesicles until secretion by exocytosis
Negative feedback
it prevents overactivity of hormones
Positive feedback
occurs when the biological action of hormones causes additional secretion of hormones
ex, secretion of estrogen before ovulation stimulates lh