BIO 169 Exam 5 Prep (Answered) 417 Questions and Correct
Answers With Complete Verified Solution, Latest Update (Fall
2024/2025) 100% Verified.
What are the similarities between nervous and endocrine system?
Both respond to stimuli by releasing a ligand;
Ligands bind receptors on target cells causing a cellular response
What is the ligand for nervous system? Endocrine system?
Neurotransmitter; Hormone
What are the differences between nervous system and endocrine system?
The nervous system
- controls a specific location in the body by way of the neuron
- effect is rapid (electrical potentials are fast) but short-lived
-Neurons need to continually release neurotransmitter to have a longer effect
Endocrine system
- Release hormone into the bloodstream thus causing a widespread response throughout the body
- Effect has a delayed response time but lasts longer
- some hormones can stay in the blood for many days
What area does the nervous system control? endocrine system?
Controls a specific location;
releases hormone so has a widespread response
What is the effect of the nervous system? endocrine system?
It is rapid but short lived so neurotransmitters continually release neurotransmitter to have longer effect;
Its a delayed response but lasts longer so can stay in the blood for many days
What is continuously present within our blood?
Many hormones are continuously present within our blood at varying levels
Why must hormone regulation be tightly regulated?
To prevent potential clinical consequences
- Ex: diabetes, hypothyroidism, gigantism
What two factors influence hormone concentration and must be balanced?
Hormone release - directly related (more released = higher concentration)
Hormone elimination - inversely related (more eliminated = lower concentration)
What are some examples of hormone elimination?
,Enzymatic degradation by liver;
Excretion by kidneys (water-soluble hormones);
Uptake by target cells
What is half-life?
Amount of time necessary to reduce the hormone concentration to half of what was originally secreted
What does the half-life look like for water-soluble? Lipid-soluble?
Water-soluble is short half-life (usually an hour or less)
Lipid-Soluble are the longest half-life due to carrier proteins within blood
If it has a shorter half life what does this mean?
It means it must be replaced more frequently
What is an example of lipid-soluble and their half-life?
Testosterone can last up to 12 days
What are circulating hormones?
Hormones that enter the blood grouped according to their chemical structures
What are the three general categories of circulating hormones?
Proteins, Biogenic amines, Steroids
What is the protein category for Circulating Hormones?
Proteins are water-soluble and the most common;
- includes small peptides, large polypeptides and glycoproteins
What is an example of proteins?
ADH, Insulin, Glucagon, GH and EPO
What is the biogenic amines for circulating hormones?
Are typically water-soluble modified amino acids; however TH's are lipid-soluble
What is another name for biogenic amines?
Monoamines
What are examples of biogenic amines?
EPI and Norepi, and melatonin
Thyroid hormones too (these are lipid-soluble)
What is the steroids for circulating hormones?
They are lipid-soluble molecules synthesized from cholesterol
,What are examples of steroids?
estrogen, progesterone, testosterone, corticosteroids (cortisol), and mineralocorticoids (aldosterone)
What are local hormones?
Signaling molecules that do not circulate within blood
What are eicosanoids?
Primary category of local hormones
What are the three types of eicosanoids?
Prostaglandins, thromboxanes, leukotrienes
Which eicosanoids category is the most diverse? What does it do?
Prostaglandins; stimulate pain receptors, induce fever, and increase inflammatory response
What medications block the formation of prostaglandins?
Aspirin, ibuprofen, and other NSAIDs;
This means that it block pain, so it decreases fever and inflammation
What are autocrine stimulation?
hormone works on the same cell it is secreted from
What are paracrine stimulation?
hormone works on neighboring cells near the cell it is secreted from
What is an example of autocrine stimulation?
IL-2 released by a helper T-cell activates the same helper T-cell released from
What is an example of paracrine stimulation?
IL-2 released by helper T-cells activates the neighboring cytotoxic T-cells
What kind of carrier proteins are there?
There are specific and nonspecific;
It can be specific to the hormone they bind with (like thyroxine-binding globulin)
It can be nonspecific meaning they bind with any lipid-soluble hormone (most albumins are nonspecific)
What do lipid-soluble hormones require to transport?
They require water-soluble carrier proteins synthesized by the liver
What percent of lipid-soluble hormones are unbound?
0.1-10% are unbound and able to exit the blood and bind receptors of target organs;
The unbound hormones are maintained at a certain level within the blood
, What percent of lipid-soluble hormones are bound?
90-99.9% are bound but are a readily available source
Do water-soluble hormones require carrier proteins?
No
Is it possible for water-soluble hormones to be bound to carrier proteins? Give an example
Some are bound to carrier proteins to prolong the life of the hormone; Insulin-like growth factor
What are lipid-soluble hormones?
They are small, nonpolar molecules that are lipophilic so can diffuse directly through the plasma
membrane of a target cell
How are hormone-receptor complex formed?
Lipid-soluble hormones bind receptors within the cytosol or nucleus of a target cell
What do the HRC's do?
They then enter the nucleus (if not already there) to bind specific sections of the DNA called hormone-
response elements (HRE's)
What does the binding of HRC's to HRE's cause?
It causes the transcription of a specific gene into a mRNA
What is mRNA used for?
To synthesize a specific protein to change the cells function
What does the protein synthesized result in?
In either:
Alteration in cell structure (growth)
Shift in the cell's metabolic activities (enzymes)
What does the lipid-soluble hormones transportation look like?
They bind receptors within the cytosol or nucleus of a target cell to form hormone-receptor complex;
HRC's then enter the nucleus to bind specific sections of the DNA called Hormone-response elements;
the binding of HRC's to HRE's causes transcription of a specific gene into a mRNA;
the mRNA is then used to synthesize a specific protein to change the cells function;
protein synthesized results in either:
- alteration in cell structure
- shift in cell's metabolic activities
What does the water-soluble hormone transportation look like?
Binding of a receptor on the membrane initiates a series of biochemical events within the cell called
signal transduction;
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