Endocrine Hormones

Question Answer
What are ductless and secrete hormones into the bloodstream? Endocrine Glands
What travel to target cells that contain receptor protiens for it? Hormones
What are secreted into the blood stream by specialized neurons? Neurohormones
What type of hormones are derived from tyrosine or tryptophan? Amine
What are 4 types of amine hormones? Norepi, epi, thyroxine, and melatonin
Polypeptide and protein are chemical classification of hormones that are chains of what? Amino acids
Hormones affect the ____________ of their targets. Metabolism
What are 7 types of polypeptide and protein hormones? ADH, GH, insulin, oxytocin, glucagon, ACTH, and PTH
What are 3 type of glycoprotein hormones? LH, FSH, TSH
What chemical classification of hormone are lipids that are derived from cholesterol? Steroids
What are 5 types of steroid hormones? Testosterone, estrogen, progesterone, aldosterone and cortisol
What 2 hormones are lipids that can diffuse into target cells? Steroid and thyroid
What is an example of a precursors of hormones? Preproinsulin
What is an example of a precursors of prohormones? Preproinsulin
What is the prehormone of the thyroid? Thyroxine (T4)
Some hormones are inactive until activated by target cells for example thyroxine (T4) is inactive until converted to what in the target cell? T3
T/F Both the NS and the endocrine system use chemicals to communicate. True
2 hormones that work together to produce an effect or produce a larger effect together than individual effects added together is called what? Synergistic
T/F A tissue usually responds to only one hormone False
The action of one hormone inhibits the effect of another is called what? Antagonistic
A hormone is said to have a _______ effect on the action of a 2nd hormone when it enhances the responsiveness of a target organ to the 2nd hormone. Permissive
The time required for blood levels to be reduced by half and ranges from minutes to hours is refered to as what? Half-life
What occurs when a hormone induces more of its own receptors in target cells and results in greater response in the target cell? Priming effect (upregulation)
Normal tissue responses are produced only when _________ are in physiological range. Hormone
High pharmacological doses can causes a # of ________ _________ probably by binding to receptors of different but closely related other hormones. Side effects
What occurs after long exposure to high levels of polypeptide hormones? Desensitization (downregulation)
After desensitization subsequent exposure of this hormone produces a ________ response due to a decrease in the number of receptors on the targe. Lesser
What does most peptide hormones have that prevents downregulation? Pulsatile secretions
In the mechanisms of hormone action, a target cell receptor shows what 3 things for a hormone? specificity, high affinity and low capacity
Lipophilic hormones have receptors in what 2 areas of the target cell because it can diffuse thru the plasma membrane? cytoplasm and/or nucleus
What is the mechanism in which steroid hormones exert their effects by entering their target cells and binding to nuclear receptor proteins and influence their target tissue by stimulating genetic transcription? Genomic action
The receptors for the lipophilic hormones are known as what because they function within the cells nucleus to activate genetic transcription (mRNA)? Nuclear hormone receptors
The nuclear hormone receptors function as ________ factors that must 1st be activated by binding to their hormone ligand. Transcription
The nuclear receptors are said to constitute a superfamily composed of what two major families? Steroid and thyroid family (includes vitamin D and retinoic acid)
What are lipophilic molecules that play an important role in the regulation of cell function and organ physiology? Vitamin D and retinoic acid
What are the 2 regions that each nuclear homone receptor has? Ligand (hormone)-binding domain and a DNA-binding domain
The hormone receptor must be activated by binding to its hormone ligand before it can bind to a specific region of the DNA which is called a __________-__________ element. Hormone-response
In the mechanisms of steroid hormones the process of two receptor units coming together at the two half-sites is called what? Dimerization
The hormone response element (HRE) of a steroid hormone comsists of what? 2 half sites
What stimulates transcription of target genes of a steroid hormone? Dimerization
In the mechanism of thyroid hormone action 99.96% of T4 in the blood is boundto a carrier protein called what? Thyroid binding globulin (TBG)
What is the only thyroid hormone that can enter the cell? Free thyroxine and T3
What does protein bound thyroxine serve as? Reservoir
Thyroid secretes __% T4 (thyroxine) and __% T3 90/10
What thyroid hormone binds to a receptor protein located in the nucleus? T3
Where is T4 converted to T3? Inside the cell
In the mechanism of thryoid hormone action ___ and ________ bind to 1 half-site and the other half-site binds to ________ ____. T3 and receptor/retinoic acid
The 2 partners for the receptor for T3 form a _________ that activates the hormone response element which stimulates transcription of the target gene. Heterodimer
Where is the receptor located for hormones that are water soluable and use a 2nd receptor? Cell surface
Why does water soluble hormones use cell surface receptors? Because they cannot pass through the plasma membrane
With hormones that use a 2nd messenger the hormone is the ______________ signal and the 2nd messenger carries the signal from the receptor to the inside of the cell. Extracellular
What type of 2nd messenger system is used by insulin? Tyrosine kinase
Insulin stimulates glucose uptake by means of what? GLUT 4 carrier proteins

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