BioScience Dictionary

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Found Steroid 31 times.

Displaying results 1 to 10.

1. Adrenal gland
This gland is found above each kidney, and it made up of an outer wall ( cortex ) that secretes important steroid hormones and an inner portion (medulla) that produces adrenaline (epinephrine) and noradrenaline (norepinephrine) .

2. Aldosterone (aldocortin)
A steroid hormone that is produced by the adrenal cortex and mainly functions to regulate chloride, potassium, and sodium metabolism . Abnormally high levels of this hormone cause symptoms such as sodium retention, high blood pressure, heartbeat irregularities and possibly paralysis.

3. Asteroid impacts
Hypothesis that links certain mass extinction events with the impact of a comet or asteroid, most notably the mass extinction 65 million years that caused the disappearance of dinosaurs and many other reptilian groups. Asteroid impacts early in earth history also contributed to the formation of the atmosphere and oceans.

4. Bile salts
Amphipathic compounds that aid digestion and lipid absorption; they are derived from steroid s and have some detergent properties.

5. Catecholamine (andrenergic amine)
Any hormone s (e.g. epinephrine) that affects the sympathetic nervous system and is a derivative of the steroid catechol, which is derived from the amino acid tyrosine .

6. Cholestane
A hydrocarbon (molecule of carbon and hydrogen only) with 27 carbon atoms that is the parent structure of all mammalian steroid s.

7. Cholesterol
A lipid which higher organisms use in the construction of cell membranes and as a precursor molecule in steroid synthesis. If a person produces too much cholesterol, the excess often gets laid down on the interior of blood vessels as plaque, causing heart disease, hardening of the arteries, and often heart attacks or strokes. Cholesterol is carried through the bloodstream in molecules called lipoprotein s. There are two major types: low density lipoproteins (LDLs, also known as "bad" cholesterol) and high density lipoproteins (HDLs, aka "good" cholesterol). When your doctor measures your cholesterol, he takes readings of the different types of cholesterol in your blood: Total Cholesterol: * Desirable: less than 200 mg/dl * Borderline High: 200-239 mg/dl * High: more than 240 mg/dl LDL Cholesterol * Desirable: less than 130 mg/dl * Borderline High: 130-159 mg/dl * High: more than 160 mg/dl HDL Cholesterol * Desirable: more than 35 mg/dl * Risk Level: less than 35 mg/dl. Those with high cholesterol are generally advised to engage in aerobic exercise, lose weight (if they are overweight), avoid eating foods high in saturated fats and cholesterol, and quit smoking (smoking raises the amount of LDL in the blood). Having elevated amounts of triglyceride s in your blood may also increase the risk of heart disease (a normal reading is less than 200 mg/dl). You can generally lower the amount of triglyceride in your blood by exercising, eating a low-fat diet, and losing weight.

8. Cholesterol
Cholesterol is absorbed from the intestine and contained in chylomicron which brings the cholestrol to the liver. Some cholesterol is synthesized by the liver. Cholesterol is the precursor of steroid hormones and constituent of cell membranes. Some cholesterol is excreted in the bile. The rest of cholesterol is carried in blood by lipoproteins. Lipoproteins in serum are classified according to their density. High-density lipoproteins (HDL), low-density lipoproteins (LDL), and very low density lipoproteins (VLDL). Each fraction contains cholesterol. It is the proportion of cholesterol in these fractions of lipoprotein that is associated with the risk of atherosclerotic heart disease (ASHD): the higher the level of LDL cholesterol, the greater the risk of ASHD, and the higher the level of HDL cholesterol, the lower the risk of ASHD. Lowering the serum cholesterol level in patients without cardiac disease do not reduce mortality rate. Lowering the cholesterol level in cardiac patients clearly reduces mortality. This reduction of risk is proportional to the reduction in LDL cholesterol and the increase in HDL cholesterol. (Normal ranges for serum cholesterol are 1.2 - 6.5 mmol/L)

9. Cortex
1) The outer part of an organ, e.g., the adrenal cortex, which produces several steroid hormones ; 2) in plants, the region of the stem or root between the epidermis and the vascular bundle(s) .

10. Corticosteroid
A steroid hormone produced in the adrenal cortex .

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