Idiopathic: An adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause.
Immune Response: A response from the body to an antigen that occurs when the antigen is identified as foreign and that induces the production of antibodies and lymphocytes capable of destroying the antigen or making it harmless.
Impotence: Inability to attain or sustain an erection.
Insomnia (see Sleep Disturbance)
Interstitial Cystitis (see Painful Bladder Syndrome)
Intoxication: Condition of body tissue affected by a poisonous substance. Poisonous materials, or toxins, are to be found in heavy metals such as lead and mercury, in drugs, in chemicals such as alcohol and carbon tetrachloride, in gases such as carbon monoxide, and in radioactive materials.
Irritability: Irritability is an excessive response to stimuli, usually used to refer to an anger or frustration.
Kidney: One of a pair of organs that maintain water balance and expel metabolic wastes. Human kidneys are bean-shaped organs about 4 in. (10 cm) long, in the small of the back. They filter about 4.5-liter water content of the blood every 45 minutes. Glucose, minerals, and needed water are returned to the blood by reabsorption. The remaining fluid and wastes pass into collecting ducts, flowing to the ureter and bladder as urine.
Kidney Failure (Renal Failure): Medical condition when the kidneys are not able to regulate water and chemicals in the body or remove waste products from your blood.
Kidney Stones: The term commonly used to refer to stones, or calculi, in the urinary system. Stones form in the kidneys and may be found anywhere in the urinary system. They vary in size. Some stones cause great pain while others cause very little.
Leydig Cells: Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone (LH).
Libido (Sexual Desire): Instinctual psychic energy that in psychoanalytic theory is derived from primitive biological urges (as for sexual pleasure or self-preservation) and that is expressed in conscious sexual activity.
Lipitor: A trademark used for the drug atorvastatin, drug, potent in reducing LDL cholesterol.
Locus of Control: A theory in personality psychology referring to the extent to which individuals believe that they can control events affecting them.
Low-density Lipoprotein: A complex of lipids and proteins, with greater amounts of lipid than protein, that transports cholesterol in the blood. High levels are associated with an increased risk of atherosclerosis and coronary heart disease.
Low Testosterone: A decrease in the normal level of testosterone hormone produced by the testes.
Luteinizing Hormones (LH): Luteinizing hormones stimulate the gonads to secrete sex steroids and are also known in men as interstitial cell stimulating hormones (ICSH). LH is created in the pituitary cells, the same ones that synthesize FSH. The National Cancer Institute website describes the role of LH as "to make testosterone." Decreased production of LH can result in fertility problems due to low sperm counts in men.
Male Hormones (see Androgens)
Male Menopause (see Anropause)
Masculinity: A set of qualities, characteristics or roles generally considered typical of, or appropriate to, a man.
Masturbation: Excitation of one's own or another's genital organs, usually to orgasm, by manual contact or means other than sexual intercourse.
Mental Health: The World Health Organization describes mental health as "a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community".
Metabolism: Metabolism refers to all the physical and chemical processes in the body that convert or use energy, such as breathing, circulating blood, controlling body temperature, contracting muscles, digesting food and nutrients, eliminating waste through urine and feces, and functioning of the brain and nerves.
Midlife Crisis: A period of psychological doubt and anxiety that some people experience in middle age.
Mood Swings: Alternations of a person's emotional state between periods of euphoria and depression.
Morning Erection: Morning Erection (or Nocturnal penile tumescence, abbreviated as NPT) is a spontaneous erection of the penis during sleep or when waking up. All men without physiological erectile dysfunction experience this phenomenon, usually three to five times during the night, typically during REM sleep. NPTs are believed to contribute to penile health.
Muscle Atrophy: Muscle atrophy is defined as a decrease in the mass of the muscle; it can be a partial or complete wasting away of muscle. When a muscle atrophies, this leads to muscle weakness, since the ability to exert force is related to mass.
Muscle Mass: Muscle mass is the actual size of the muscle. The greater the mass of a muscle is, the greater its strength.
Muscle Weakness: A condition which is characterized by an inability of the muscles to function at their full strength.
Narcolepsy: Narcolepsy is a disorder marked by excessive daytime sleepiness, uncontrollable sleep attacks, and cataplexy (a sudden loss of muscle tone, usually lasting up to half an hour).
Neurosis: A class of functional mental disorders involving distress but neither delusions nor hallucinations, whereby behavior is not outside socially acceptable norms.
Neuroticism: A fundamental personality trait in the study of psychology characterized by anxiety, moodiness, worry, envy and jealousy.
Nifedipine: A calcium-channel blocker used in the treatment of hypertension, angina pectoris, and heart failure.
Night Sweats: Night sweats are the occurrence of excessive sweating (hyperhidrosis) during sleep. The sufferer may or may not also suffer from excessive perspiration while awake.
Nocturia: Getting up to urinate multiple times during the night.
Non-REM Sleep (NREM Sleep): Non-rapid eye movement sleep; the deep, dreamless period of sleep during which the brain waves are slow and of high voltage, and autonomic activities, such as heart rate and blood pressure, are low and regular. Non-REM sleep is subdivided into 4 stages. Stages 1 and 2 constitute light sleep; stages 3 and 4 are called deep sleep. Deeper sleep generally is more refreshing.
Obesity: Condition characterized by the excessive accumulation and storage of fat in the body.
Obsessive Compulsive Disorder: An anxiety disorder that affects 1% to 2% of the population, characterized by repetitive ritualized actions and disturbing thoughts about consequences of actions or departures from ritualized behavior. The condition is popularly believed to be compatible with normal life, but it is dysfunctional. It responds to anxiolytic drugs or behavior therapy.
Obsolagnium: Decreased sexual desire, resulting from aging.
Obstructive Sleep Apnea (OSA): Sleep disorder, caused by obstructed breathing, either due to too much tissue as seen in obesity or decreased muscle tone which may be seen with low testosterone. This inhibits the air flow in the mouth and nose which causes snoring and decreased ability for adequate oxygenation during sleep. As a result, men often wake up numerous times during the night and rarely achieve deep sleep.
Orchitis: Orchitis is inflammation of one or both testicles in men, usually caused by an infection. Orchitis can result from the spread of bacteria through the blood from other locations in your body. It also can be a progression of epididymitis, an infection of the tube that carries semen out of the testicles. This is called epididymo-orchitis.
Orgasm (Sexual Climax): The sudden discharge of accumulated sexual tension during the sexual response cycle, resulting in rhythmic muscular contractions in the pelvic region characterized by sexual pleasure.
Orgastic Potency: The ability to experience an orgasm with specific psychosomatic characteristics and, among others, requiring the ability to love.
Osteopenia: A condition where bone mineral density is lower than normal. It is considered by many doctors to be a precursor to osteoporosis.
Osteoporosis: A disorder in which the bones become increasingly porous, brittle, and subject to fracture, owing to loss of calcium and other mineral components, sometimes resulting in pain, decreased height, and skeletal deformities.
Overflow Incontinence: If your bladder is always full so that it frequently leaks urine, you may have overflow incontinence. Weak bladder muscles or a blocked urethra can cause this type of incontinence. Nerve damage from diabetes or other diseases can lead to weak bladder muscles; tumors and urinary stones can block the urethra.
Overreactive Bladder (Urge Incontinence): A form of urinary incontinence characterized by the involuntary loss of urine occurring for no apparent reason while feeling urinary urgency, a sudden need or urge to urinate.