IB Chemistry Opt B Human Biochemistry B6 Hormones

B.6.1 Outline the production and function of hormones in the body.

Explanation There are two major ways for the body to communicate o Nervous System o Endocrine System- based on Hormones

Explanation Hormones are chemical messengers. hormones have a variety of structures including proteins, steroids, modified amino acids and fatty acids. They are secreted directly into the blood by endocrine glands in response to various stimuli o This is because the glands do not have ducts Hormones are transported using the blood stream

Explanation Once the hormones are made, they only bring responses in cells that have receptors for them AKA TARGET CELLS

Explanation Examples o Antidiurectic Hormone (ADH)  controls body water content o aldosterone,  Steroid  regulates sodium potassium balance in the blood o estrogen, o progesterone o testosterone, o insulin, o epinephrine (adrenaline) o thyroxine

Functions Endocrine Gland that Produces it HormoneFunctionTarget Cells PituitaryAntidiurectic Hormone (ADH) increases uptake of water; helps control osmotic potential of the blood Kidney Tubules Thyroid GlandThyroxinestimulates growth and metabolismAll cells Adrenal CortexAldosteroneIncreases uptake Na+ by kidneys and helps control Na+ and K+ ratios in fluids; raises blood pressure Kidney Tubules Adrenal MedullaAdrenalinereleased during excitement/stress. Causes dilated pupils and an increase in blood glucose and increases blood supply in muscles Most of body ex/ muscles, brain etc

Functions Endocrine Gland that Produces it HormoneFunctionTarget Cells PancreasInsulindecreases blood glucose level. made up of 2 poypeptide chains held together by disulfide bonds; regulates cellular intake of glucose from the blood all cells especially Liver! OvaryEstrogen and Progesterone Development of female secondary sexual characteristics; control of menstrual cycle, growth and development of placenta and fetus Most parts of body especially Uterus lining (during pregnancy) TestesTestosteroneDevelopment of male secondary sexual characteristics Many parts of Body

Sample Questions Outline the production and function of hormones in the body. HormoneFunction Antidiurectic Hormone (ADH) increases uptake of water; helps control osmotic potential of the blood Thyroxinestimulates growth and metabolism AldosteroneIncreases uptake Na+ by kidneys and helps control Na+ and K+ ratios in fluids; raises blood pressure Adrenalinereleased during excitement/stress. Causes dilated pupils and an increase in blood glucose and increases blood supply in muscles Insulindecreases blood glucose level. made up of 2 poypeptide chains held together by disulfide bonds; regulates cellular intake of glucose from the blood Estrogen and Progesterone Development of female secondary sexual characteristics; control of menstrual cycle, growth and development of placenta and fetus TestosteroneDevelopment of male secondary sexual characteristics

Sample Questions Identify which of the two hormones is the female sex hormone and where in the human body it is produced. (2) Progesterone is the female sex hormone and is produced in the ovaries.

Sources Higher Level Chemistry Developed Specifically for the IB Diploma by Catrin Brown and Mike Ford IB Study Guides Chemistry by Geoffrey Neuss

B.6.2 Compare the structures of cholesterol and the sex hormones.

Explanation Sex hormones all belong to a family of organic compounds called steroids (lipids) Consist of four contiguous carbon rings o Common steroid backbone Different steroids have different functional groups and side chains Variable group

Explanation Cholesterol = most common steroid Essential in cell tissue, brain and nervous tissue Chain of alkanes on one ring with -OH (hydroxyl) group on last ring

Male Sex Hormones Testosterone and Androsterone Produced in testes Characteristics:  Anabolic - encourage the growth of tissue, muscle and bone  Androgenic - Control the development and maintenance of masculine characteristics

Structure Testosterone Steroid backbone with one hydroxyl (-OH), one ketone functional group (-C=O) and one alkene functional group (C=C)

Female Sex Hormones Oestradiol/estrogen and Progesterone Produced in ovaries from puberty until menopause Responsible for sexual development and menstrual reproductive cycles in women

Structure Oestradiol/estrogen Steroid backbone with two hydroxyl functional groups (- OH) and benzene ring with alternating C=C bonds (aromatic compound) Progesterone Steroid backbone with two ketone functional groups (C=O) and one alkene functional group (C=C)

Sample Questions Study the structure of the two sex hormones oestradiol and testosterone given in the Data Booklet. List the differences between the two structures. Oestradiol Testosterone Structural Differences 2 -OH functional groups Benzene ring with alternating C=C bonds 1 -OH group 1 -C=O (ketone) group 1 -C=C (alkene) group

Sample Questions 7. The structures of two sex hormones, progesterone and testosterone, are shown in Table 22 of the Data Booklet. (a) State the names of two functional groups that are present in both hormones. (2) carbonyl/ketone, alkene

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B.6.3 Describe the mode of action of oral contraceptives.

The Menstral Cycle and Pregnancy beginning of the menstrual cycle o pituitary gland releases follicle-stimulating hormone (FSH) o FSH travels to the ovaries --> causes release of estrogen  prepares for release of an egg from the ovary  prepares for build-up of the uterine wall to accept the egg once it is fertilized

The Menstral Cycle and Pregnancy (cont.) after two weeks the luteinizing hormone (LH) o is released from the pituitary gland o travels to the ovaries o releases progesterone which causes the egg to be transported to the uterus o build up the uterine wall continues If the egg is fertilized o egg embeds in the uterine wall o hormone levels rises dramatically If the egg is not fertilized o hormone levels fall o menstruation begins

Oral Contraceptive aka The "Pill" consists of estrogen and progesterone hormones the increase in the levels of these hormones o prevents ovulation o inhibits pituitary gland from producing LH and FSH  stops the development of the utuerine linning --> prevents the attachment of the egg to the wall of the uterus o thickens the mucus around the cervix preventing sperm from entering the uterus

Sample Questions Outline the mode of action of oral contraceptives(3). Answer: Estrogen- and progesterone-containing oral contraceptives inhibit the release of LH releasing hormone, which suppresses levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH), therefore preventing follicular development and ovulation

Sources image: control-and-family-planning/background.html

B.6.4 Outline the Use and Abuse of Steroids

Uses Help a person to recuperate from a major illness o Build muscle growth due to inactivity (AIDS and anemia)

Uses (for Women) Female Hormones o ex. estrogen, progesterone: hormone replacement therapy (HRT) for menopausal women, contraceptive pill

Uses (for Men) Male hormones (androgens) o ex. testosterone: treatment of disorders of testes and breast cancer. o These hormones are also known as anabolic steroids as they promote tissue growth especially muscles. o Increase weight in patients from weight loss

Abuses Main people who abuse steroids are athletes o Change appearance of person o Build muscle o Increase athletic ability

Abuse in Steroids (side effects) Liver tumorsMental state of abuser harmed High blood pressureSkeletal growth Fluid retentionHeart disorders Increase in bad cholesterol levels (LDL)Decrease in good cholesterol levels (HDL) Kidney tumorsJaundice Severe acne

Male Side Effects No babies (Infertility)Frequent urination Lowers the amount of spermDevelops breasts Testicular shrinkingRisk of Prostate cancer Causes baldness

Female Side Effects Facial HairCause of male baldness Voice deepensAbnormal scheduling (menstrual cycle)

Sample Questions Are there any current treatment options for steroid abusers? o No, there are no current treatments because no scientists are really looking into it. However, there are some scientists that have patients from steroid withdrawal and their idea treating steroid abuse is to educate everyone with the side effects and harms of steroids.

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