• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/62

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

62 Cards in this Set

  • Front
  • Back
Cells not in direct contact communicate w/ each other by?
Chemical messengers
What is endocrine signaling?
Hormones secreted into ECF & carried by circulatory system to distant targe cells
What is paracrine signaling?
Hormones secreted into ECF & carried by diffusion to nearby cells
What is autocrine signaling?
Target cells of the same type act as secreting cells
What are the classical endocrine glands? (8)
1. Hypothalamus
2. Pituitary gland
3. Adrenal gland
4. Pancreas
5. Testes
6. Ovaries
7. Thyroid gland
8. Parathyroid glands
What is sensitivity?
How a tissue responds to the hormone
What is availability?
Concentration of hormone in target tissue
WHat are the factors that determine how a tissue is influenced by a hormone? (5)
1. Quantity secreted
2. Transport in plasma
3. Activation of prohormone
4. Inactivation
5. Removal from system
How are hormones classsified? (3)
1. Peptide & protein hormones
2. Amino acid-derived hormones
3. Steroid-derived hormones
Examples of peptide & protein hormones? (2)
1. Thyrotropin releasing hormone TRH
2. Glucagon
What factors are important in regulation? (2)
1. Inactivation
2. Removal
Examples of amino-acid derived hormones? (2)
1. Epinephrine
2. Thyroxine (T4)
Examples of steroid hormones? (2)
1. Progesterone
2. Vitamin D
Two general mechanisms of hormones?
1. Cell membrane receptors
2. Intracellular receptors in cytoplasm or nucleus
Which types of hormones act by membrane receptors? (3)
1. Polypeptide hormones
2. Protein hormones
3. Catecholamine hormones
Which types of hormones act by intracellular receptors? (3)
1. Thyroid hormones
2. Steroid hormones
3. Steroid-derived hormones
Protein kinase A phosphorylates which residues on proteins?
Serine or threonine
What are C-response element binding proteins? (CREB)
Transcription factors which influence gene expression
What enzyme hydrolyzes cAMP to AMP to turn response off?
Phosphodiesterase
What do tyrosine kinase receptors do when hormone binds?
Autophosphorylation of tyrosine-OH
What puts the mitogen activated protein kinase MAPK phosphorylation cascade in action?
Tyrosine kinase activity
Growth factors often work through what type of receptors?
Tyrosine kinase receptors
Growth hormone acts through what type of receptors?
Receptors associated w/ tyrosine kinases
Binding of GH to receptors associated w/ tyrosine kinases activates?
JAK kinases
JAK kinases phosphorylate each other, the receptor and?
STAT
What happens once STAT is phosphorylated?
STAT protein forms dimers & pass into nucleus where they act on gene expression
Heat shock proteins act as?
Chaperone proteins
Hormone binds cytosolic receptor, heat shock proteins dissociate, and what happens to hormone-receptors?
Hormone-receptor complex & form dimers that can bind DNA
How does thyroid hormone, VItamin D & PPRAR act on gene expression?
Hormone binds heterodimer on DNA
Thyroid gland is made up of?
Follicles
What cell type lines follicles? What fills lumen of follicles?
Follicular cells line follicle
Colloid fills lumen
Follicular cells secrete? (2)
1. Thryoxin (T4)
2. Triiodothyronine (T3)
What is located between follicles? (2)
1. Capillaries
2. Parafollicular or C cells
What do C cells secrete?
Calcitonin
Which is the active form of thyroid hormone?
T3
What does the thyroid gland actually secrete?
T4 (thyroxine)
Iodide is transported into follicle cell from blood by?
Active transport
Na/ I symporter
What happens iodide enters follicle?
Iodide coupled to tyrosine residues in thyroglobulin
Iodide coupled to thyroglobulin produces? (2)
1. Monoiodotyrosine (MIT)
2. Diiodotyrosine (DIT)
In healthy thryoid, which form is made more? MIT or DIT?
DIT
MIT & DIT residues couple to form?
T3 & T4 residues linked to thyroglobulin
Colloid is?
Storage of thyroglobuiln bound to T3 & T4 in follicle
How is thyroglobulin taken back into follicular cells?
Endocytosis
Hydrolysis of thyroglobulin produces amino acids including?
T3 & T4
Enlarged thyroid gland is due to?
Diet deficiency of iodine
TRH is secreted by?
Hypothalamus
TRH stimulates secretion of?
TSH by anterior pituitary
TSH stimulates?
Growth & metabolism of thyroid follicle cells--> secretion of T3 & T4
TSH acts via what type of signaling pathway?
AC --> cAMP --> PKA
Secretion of TSH is regulated by?
Negative feedback of T3 & T4 on TSH (thyrophrons not able to respond to TRH)
T4 is carried through blood bound to which proteins? (3)
1. Thyroid-binding globulin (TBG--mostly)
2. Transthyretin (TTR or TBPA)
3. Albumin
T3 is carried through blood bound to which proteins? (2)
1. TBG (mostly)
2. Albumin
What percentage of T4 is bound in healthy adults?
99.98%
Free T4 in blood corresponds to?q
Concentration that correlates w/ physiologic responses to thyroid hormones
How are thyroid hormones activated or inactivated?
Deiodination
What converts T4 --> T3?
5'-deiodinases
What is the prohormone of thyroid hormones?
Circulating T4
5-deiodinase can convert T4 into? (2)
1. Active T3
2. Reverse T3 (inactive)
Thyroid hormones & their metabolites may be converted to water-soluble products by coupling them to?
Glucuuronic acid & cleared into urine
Actions of thyroid hormones? (8)
1. Increase tissue respiration (O2 consumption & heat production)
2. Stimulate body growth & CNS development
3. Stimulate nervous system activity
4. Increase carbohydrate absorption
5. Increase carb & lipid metabolism
6. Lower blood cholesterol
7. Increase beta-adrenergic receptors (sensitve to epinephrine)
8. Stimulate bone turnover
Where is T3 receptor located?
TR located in nucleus bound to DNA
What happens when T3 binds TR?
Activity of polymerase II is altered changing gene expression