Unit 4 Flashcards
What are the three ways that cells appear to communicate with other cells?
Indirect signlaing by secreted chemicals
Direct signaling by plasma membrane bound molecules
Direct signaling via gap junctions
What are the three classes of mammalian hormones based on?
Based on transit of hormone from cell of origin to target site
What are the three classes of mammalian hormones?
Paracrine
Endocrine
Autocrine
Neuroendocrine signaling
_______ hormones are released into extracellular space, diffuse to neighboring target cells
Paracrine
_______ hormones are released into blood and carried to target cells
Endocrine
_________ hormones affect the cell where they’re produced by binding to their own surface receptors
Autocrine
Eicosanoids are examples of ________ hormones
Insulin and glucagon are examples of _________ hormones
Paracrine
Endocrine
_______ hormones bind to plasma membranes receptors and operates through second messengers
Water-soluble
How are Water soluble hormones transported in the blood?
Free form
__________ hormones bind to nuclear receptors and operates through gene regulation
Lipid-soluble hormones
How are lipid soluble hormones transported in blood?
Bound to proteins
_________ receptors are involved in Hormone-receptor interactions that generates second messengers
Metabotropic receptors
Hormone receptors signaling via _______
Secondary messengers
Receptors present in the plasma membrane that generates second messsengers when bound to a hormone is known as a
Metabotropic receptors
What are examples of peptide hormones?
Insulin and glucagon
Peptide hormones are synthesized as _______ and act on plasma membrane receptors to generate ______
Prohormones; second messenger
***Prohormone examples preproinsulin -> preinsulin -> insulin
Peptides, catecholamines and eicosanoids hormones act by what way?
Binding to plasma membrane receptors and generate second messengers
Catecholamines are synthesized from ______. What is an example?
Tyrosine; epinephrine
What are eicosanoids synthesized from?
What is an example?
Arachidonate; prostaglandins
Steroid is synthesized from ______. And an example is _________
Cholesterol; testosterone
Vitamin D is synthesized from _______. And example is _____
Cholesterol; calcitriol
Retinoid is synthesized from _______. An example is _______
Vitamin A; Retinoate
Thyroid hormones are synthesized from _______. An example is _______
Thyroglobulin; Triiodothyronine (T3)
What types of hormones act by way of binding to nuclear receptors and regulate gene expression?
Steroid, vitamin D, retinoid, thyroid hormones
Nitric oxide hormones are synthesized from _____ and _____ and act by way of ________ receptor thus generating a second messenger
From arginine and O2
Cytosol is receptor
What neurotransmitter is active in the CNS and PNS?
Acetylcholine
What us the amino acid precursor of acetylcholine?
Serine
What two components combine to form Ach?
Choline + Acetyl-CoA
*** Choline is produced by Serine
_________ receptor is an ion channel to where the ligand receptor interactions opens up the ion channel. What is an example of this receptor?
Ionotropic
Ex: Ach receptors
Propagation of the impulse involves opening of ________ channels
Voltage gated Na+
Opening of _________ channels at the end of the axon triggers the release of the neurotransmitter Ach
Voltage gated Ca2+
_______ opens the ligand gated ion channel (ionotropic receptor) on the receiving cell
Ach
_______ is synthesized by the beta cells of pancreas during the _____ state (after eating a typical meal)
Insulin ; Fed state
What are the target cells of insulin?
Liver, muscle, or fat tissue cells
What does the binding of insulin to the insulin receptor initiate?
A cascade of event that leads to increased glucose uptake and metabolism
What precursor of insulin has the signal sequence, C-peptide, and the alpha and beta chain?
Preproinsulin
What precursor molecule of insulin has the signal sequence removed but C peptide is present?
Proinsulin
What is the functional insulin made up of?
Alpha and beta chain
** functional once C-peptide is removed from Proinsulin
Insulin is a _______ hormone with 51 amino acids
Peptide
Where is insulin made?
Beta cells of pancreas
Insulin is high in blood during the _____ state. It’s release is stimulated by what?
Fed state; high blood glucose
During the fed state when there is high blood glucose, what organs are affected and result in an increase in uptake of glucose?
Muscle
Adipose tissue
Liver
When insulin is present, what biomolecules are synthesized?
Glycogen
Fat
Cholesterol
Protein (to lesser extent)
Inability to make or respond to insulin results in _______
Diabetes
_______ is synthesized by the alpha cells of the pancreas during ______
Glucagon; fasting state
What is the precursor of glucagon?
Proglucagon
Glucagon is a ______ hormone made up of 29 amino acids
Peptide
When is glucagon increases only when ________ is low
Blood glucose
Glucagon is high in blood _______ and _____
Between meals and overnight (fasting)
What cels do glucagon effect?
Hepatocytes mostly
What does glucagon lead to in hepatocytes?
Increase in production and release of glucose
High glucagon leads to _____ in degradation of ______ and ______
Increase; Glycogen and fat
Increase of glucagon release results in ________ synthesis of cholesterol, fat and glycogen
Decreased
Where is epinephrine synthesized from? What causes it to be secreted?
The adrenal glands during stress, like exercise or starvation
______ is the end product of modifying tyrosine by sequential chemical reactions that generate other signaling molecules as well
Epinephrine
Complete the pathway of synthesis to epinephrine
Tyrosine-> ________ -> dopamine-> _____ -> epinephrine
L-DOPA; Norepineprhine
Epinephrine is a _______ Hormone synthesized by ______
Catecholamine; tyrosine
______ is produced by the adrenal glands and secreted during times of stress from starvation or exercise
Epinephrine
High epinephrine leads to degradation of _____ and ______. Decrease synthesis of ______, _____ and _____.
Increased degradation:
Glycogen, fat
Decreased synthesis of cholesterol, Fat and glycogen
Epinephrine secretion leads to increased O2 to tissues resulting in what 3 things?
Increased heart rate
Increased blood pressure
Increased vasodilation
What plays vital roles as signaling molecules between near by cells (paracrine signlaing)
Biologically active signaling
What are 3 examples of biologically active lipids
Eicosanoids
Steroid hormones
Lipid soluble vitamins (A,D,E,K)
What is the vitamin precursor of the coenzyme TPP?
Thiamin
What is the vitamin precursor of the coenzyme FAD/FMN?
Riboflavin
What is the vitamin precursor of the coenzyme NAD+/NAP+?
Niacin
What is the vitamin precursor of the coenzyme CoA and ACP?
Pantothenate