topic 13 powerpoint 13.0 Flashcards
Steroids
-type of lipid
-membrane permeable
- refers to both naturally occurring hormones produced by the body and synthetic medications that mimic the effects of these hormones.
Describe the structure of a steroid
-fused ring
-C-H nonpolar
-attached functional group
What is an example of a fungus steroid?
ergosterols: same function as cholesterol in animals
What are two plant steroids?
-phytosterol: structural component of cell membrane
-brassinosteroid: pollen tube formation, cell expansion and elongation, vascular differentiation
What is an example of a vertebrae steroid?
cholesterol
-structural component involved in membrane permeability and fluidity
- amkes up bile acids, steroid hormoes, vitamin D
-carried in lipoprotein(HDl/LDL)
Different between HDl and LDL
HDL high-density lipoprotein
-good” cholesterol because it helps remove excess cholesterol
LDL low-density lipoprotein.
- cholesterol from the liver to the cells in the body, including the cells lining the arteries.
What conditions gives rise to atherosclerosis?
having high levels of LDL and low levels of HDL in the blood
how does Cholesterol regulate membrane fluidity?
Cholesterol helps regulate membrane fluidity by preventing the fatty acid chains of phospholipids in the cell membrane from packing too closely together.
sterone
steroid acts as a hormone
steroid hormone
-corticosteroid and sex steroid
How do sterones regulate hormone secretion?
can regulate hormone secretion by binding to receptors that can activate pathway that can release hormones by endocrine glands and can inhibit hormone secretion
How are sterones identified?
by the receptor the bind to. 5 types of receptors
1. Glucocorticoids (corticosteroid)
2.Mineralocorticoids (corticosteroid)
3.Androgens (sex steroid)
4.Estrogens (sex steroid)
5.Progestins (sex steroid)
What is a sex steroid?
subset of sex hormones that produce sex differences or support reproduction
What are androgens, estrogen, progestins?
-androgens: hormones key in development of male traits, ex: testerone[male organs]
-estrogen: hormones key in development of female traits, ex: estradiol[female organs]
-progestins: hormones that are primarily involved in the regulation of the menstrual cycle and pregnancy.
What are corticosteroid?
type of steroid hormone synthesized from cholesterol in the adrenal cortex
What type of hormone involved in regulating stress hormone and can reduce immune responses?
Glucocorticoids: subset of corticosteroid aka type of steroid hormone
-role in metabolism and immune function
What type of hormone involved with the kidneys?
Mineralocorticoids: subset of corticosteroid aka type of steroid hormone
-maintain blood volume and control electrolytes and water levels by promoting sodium retention in the kidneys
What is a hormone that doesn’t regulate hormone secretion?
hint: body builder
How do they perform their function?
Anabolic steroid
Interact with androgen receptors to increase mass and bone synthesis
-natural and synthetic
-increase production of actin and myosin proteins
-blocks the effect of the stress hormone cortisol
-favor cellular differentiation into muscle cells
endocrine system
is a collection of glands that secrete hormones into the bloodstream to hit target receptor on organ.
What is the synthetic version of HGH?
HGH: human growth hormone=somatotropin
What is LH?
luteinizing hormone-stimulates ovulation
Difference between ADH and aldosterone?
ADH=antidiuretic hormone, produced by hypothalamus and released by pituitary gland, acts on kidney to increase water absorption
Aldosterone: produced by adrenal glands and acts on kidneys to promote reabsorption of sodium and excretion of potassium
T/F sweat glands are part of endocrine system
false: Exocrine glands (not part of the endocrine system) secrete products that are usually passed outside the body
(sweat glands, salivary glands). Also, the pancreas has exocrine cells.
What is a tropic hormone?
a hormone that regulates hormone secretion by another endocrine gland
What are the 4 major cell signaling in in the endocrine system?
- classical endocrine signaling: secrete hormones over a distance
- neuroendocrine signaling: neurosecretory neurons release neurohormones into the circulatory system
3.paracrine regulation: cells release local regulators that diffuse through extracellular fluid to regulate nearby cells
4.autocrine regulation: local regulators bind to same cells that produce it
What are the 4 molecular classes of hormones?
- Amine
- peptide
3.steroids - fatty acid
What type of hormones fall under the molecular class called amine?
epinephrine and norepinephrine
-made from tyrosine
What type of hormones fall under the molecular class called peptide?
PYY suppress appetite
made of amino acid chain
What type of hormones fall under the molecular class called steroid?
aldosterone, cortisol, sex hormone
made from cholesterol
What type of hormones fall under the molecular class called fatty acid?
prostaglandins
-paracrine and autocrine mediators
-bind to G-Protein-couple receptors
-produced by oxidation of cyclooxygenases[COX1/COX2]
What are the effects of prostaglandins?
-EFFECTS: dilation/constriction of vascular smooth muscle cells, aggregation of platelets, pain sensitivity, decreased eye pressure, calcium movement, cell growth, and inflammation
endocrine system has feed back systems
explain the one using GnRH hormone
NEGATIVE FEEDBACK
1.hypothalamus releases Gonadotropin-releasing hormone (GnRH) [tropin hormone], travels to the pituitary gland
A. releases LH[lutenizing hormone] and travels to the testes and binds to specific receptors on the Leydig cells. Increase in the production of testosterone.
B. releases FSH, brings to Sertoli cells in seminiferous tubules of testes, helps spermatogenesis and inhibin; inhibin negative feedback on anterior pituitary
endocrine system has feed back systems
explain the one involving thyroid
- [+ feed back]hypothalamus releases TRH[thyroid-releasing hormone] to pituitary
- [+ feedback]releases TSH[thyroid stimulating hormone] to thyroid
- The thyroid releases hormones that has negative feedback on pituitary
In our body, do we expect to find hormones in low or high concentrations?
low because of amplification because binding of a hormone to receptors activates many proteins
plasma membrane structure
plasma membrane is hydrophobic. It is composed of a phospholipid bilayer, which consists of hydrophilic heads facing the extracellular and intracellular environments, and hydrophobic tails facing each other in the middle of the membrane.
Explain difference between hydrophobic and hydrophilic hormones?
hydrophilic hormones bind to surface receptors activating second messenger pathways
hydrophobic hormones bind inside cell activating/inhibiting regulatory proteins
How can we differentiate aldosterone and epinephrine?
hydrophilic hormone: epinephrine
hydrophobic hormone: aldosterone
1) low sodium levels cause adrenal glands to secrete aldosterone
2) enters kidney cells and combines with aldosterone receptor activating it
3) active hormone receptor complex enters the nucleus and starts to transcript aldosterone-induced protein
4)aldosterone-induced protein is synthesized in the cytoplasm and act as a sodium channel allowing Na+ to enter and helps retain it
