Bio 309D
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- You first start studying an endocrine gland by removing it from an experimental animal. Describe the possible effects of such a removal.
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Castration<------>parathyroid
no effect death - you remove an endocrine organ, see what happens, and then try to overcome that effect. what do you use to try to do that?
- inject an extract from gland, if you're able to purify it, then you're able to purify the hormone.
- "Hypo" is the prefix for the syndrome when the amount of hormone is _______. "Hyper" is the prefix when the amount of hormone is ______.
- too low, too high
- Name one group of hormones which could not be discovered by the classical removal-observe-inject technique.
- Releasing factors from the hypothalamus
- Name two releasing factors andtheir immediate effect only on pituitary hormones.
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ACTH RF--causes the release of ACTH
TSH RF--causes release of TSH - Name one inhibiting factor from the hypothalamus. Why is it so called?
- prolactin IF, inhibits prolactin releasing factor
- If the pituitary is underfunctioning, what is the major effect, and what hormone (or lack of it) is involved?
- dwarfism, because you produce too little growth factor
- Name two hormones of the anterior lobe of the pituitary and their immediate effect on the appropriate endocrine gland.
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TSH--causes thyroid to release thyroxin
ACTH--causes adrenals to release cortisol - Name two hormones stored in the posterior lobe of the pituitary, and briefly describe what they do.
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ADH--controls water reabsorption in kidney
Oxytosin--causes smooth muscle contraction in the uterus - If the pituitary is overfunctioning, what is the major effect, and what causes it?
- produce too much growth hormone, gigantism
- Acromegaly is a very common syndrome seen in older people. What is its cause?
- continued slow production of growth hormone
- Hormones are divided into two major groups. Name them and give a characteristic feature of each one.
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peptide--binds to receptor and activates second messanger
Steroid--acts on cell DNA - What is the second messanger?
- cyclic AMP, made in response to peptide hormone
- A peptide hormone switches on the second messagner. How, then, is the specificity characteristic of that hormone maintained?
- hormones have specific receptors which aren't present in all cells
- What does the second messanger do to the cell?
- activates inactive proteins already present in cells and has specific effects characteristic of specific hormones
- A steroid hormone enters the cell. In brief and general terms, what happens next?
- interacts with receptor in cell and activates DNA sequence to make proteins
- The classical example of endocrine study is the male reproductive system. What "advantages" accrue from carrying out the typical procedure for the study of endocrine organs in man and animal?
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Man--unable to produce sperm, safe attendant for women b/c they have low libido
Animal--b/c animals become more placid, don't fight - Removal of the characteristically male endocrine organ can be reversed by an extract of the testes, containing _____.
- Testosterone
- What environmental aspect is vital for the production of viable sperm?
- temperature must be below body temperature
- Below a certain quite large number of sperm per ejaculate, a male is essentially sterile. Give two theories as to why this is so.
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1. because sperm have hyaluronidase (an enzyme) to digest the first layer of the egg
2. survival of the fittest - Name two vital funcitons of testosterone
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1. maturation of sperm
2. growth and development of reproductive organs - Name two 'secondary sexual characteristics' affected by testosterone.
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1. deepening of voice
2. growth of body hair - Semen is made up of three constituents. Name them.
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1. sperm
2. seminal vesicle fluid
3. prostate fluid - A sperm may live for 24 hours, an egg for 72 hours. calculate the period over which an egg can be fertilzed--showing your calculation.
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Sperm Egg Sperm
<----><--------><----->
1 day 3 days 1 day=4 days - There are three kinds of tears. Name them and describe what they do.
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continuous--keep eyes wet throughout the day
reflex--wash away irritants
psychogenic--wash away hormones like endorphins - Lutenizing hormone level in males is controlled by _____ produced by the _____.
- testosterone, testes
- The cells of Sertoli are affected by what hormone from the pituitary?
- FSH
- And what that hormone from the cells of Sertoli does is to aid in the formation of _____________.
- sperm by facilitating testosterone entry into support cells.
- The formation and accumulation of sperm induces the production of an inhibitory hormone called _____.
- inhibin
- Inhibin is a testicular hormone whos mode of action is to affect the production of ______.
- FSH
- The advantage of inhibin as a male contraceptive would be that it would specifically affect just one part of the system. Why would that be an advantage?
- leaves rest of system intact, so male still produces testosterone, maintains libido and secondary sex characteristics
- Another chemical compound leaves much of the male reproductive system intact. What is its name, and what does it affect?
- gossypol, makes sperm unable to swim as well
- What is a simple explanation for menopause in women?
- decrease in estrogen
- Primary follicles develop into ______ and then, under the influence of LH, that body changes into the ______.
- Graafian follicles, Corpus luteum
- The succession of hormones affecting the endometruim is:
- 1st: estrogen, 2nd: progesterone
- FSH derives its name from female reproductive activities. What is its full name and what does it do?
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Follicle Stimulating Hormone
initiates growth of primary follicles into Graafian follicles, which produce estrogen - LH derives its name from female reproductive activities. What is its name and what does it do?
- Lutenizing Hormone, induces ovulation and causes changes to the Graafian follices, which become the corpus luteum
- The developing oocyte may produce two hormones which affect FSH production. Their names and individual effects are:
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Inhibin: inhibits FSH
Activin: stimulates FSH - A drastic way to prevent reproductive cells from interacting is called _____ in males, and _______ in females.
- vasectomy, tubal ligation
- Outline two methods of 'contraception' which don't prevent male and female cells from interacting.
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IUD--sponge containing prostaglandins
mornding after pill--maintains high level of estrogen, which prevents surge of LH - What is the function of the pill in preventing conception?
- prevents egg from implanting itself
- What are the usual constituents of the pill and how are they delivered in the combination and sequential modes?
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Constituents--estrogen and progesterone analogs
Combination--pill has both and is taken over 28 days
Sequential--pills have estrogen for 1st 14 day and both for last 14 days - Name two reasonable possibilities for contraception in the future.
- gossypol, inhibin
- Give a short description of the disorder of the female reproductive organs called primary and secondary amenorrhea.
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Primary--never had a period and ovaries are nonfunctioning
Secondary--transient absence of menstrual cycle - Give a short description of the disorder of the female reproductive organs called dysmenorrhea. What is believed to be the reason for it?
- Very painful mentruation, overproduction of prostaglandins
- Inhibin is a testicular hormone whose mode of action is to affect the production of ______.
- FSH
- The succession of hormones affecting the endometrium is:
- 1st: estrogen, 2nd: progesterone
- A drastic way to prevent reproductive cells from interacting is called ______ in males, and ______ in females.
- vasectomy, tubal ligation
- Outline two methods of contraception which don't prevent male and female reproductive cells from interacting.
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IUD--sponge containing prostaglandins
Morning after pill--maintains high levels of estrogen, which prevents a surge of LH - What is the major function of the pill in preventing contraception?
- prevents egg from implanting itself
- Give a short description of dysmenorrhea. What is believed to be the reason for it?
- very painful menstruation, overproduction of prostaglandins
- What is endometriosis, why is it a problem, and how would you treat it?
- When endometrial tissue grows outside of the uterus. At menstruation it sloughs off and causes bleeding in the abdominal cavity. Treated by taking the pill to maintain tissue
- Endometrial tissue outside the uterus can result in the condition known as _______ and may be controlled by what method?
- endometriosis, taking the pill
- Name two symptoms of PMS.
- irritability, water weight gain
- At what time in her life is a woman most susceptible to breast cancer, and why?
- after menopause, because estrogen levels drop
- What is the difference between the trophoblastic and placental phases of pregnancy?
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Trophoblastic--corpus luteum is maintained and trophoblasts eat their way into endometrial tissue
Placental--when shared fetal and maternal tissue, nutrients pass from maternal circulatory system to fetal CS - What hormone is produced only during pregnancy?
- chorionic gonadotrophin
- When does chorionic gonadotrophin start to appear in a pregnant female?
- 6 weeks after contraception
- Give one explanation why the fetus is expelled after 270 days.
- uterus stops growing, but the fetus does not, so it starves. Hormone levels drop, causing contraction of the uterus
- Name two effects of lactation on the reproductive organs of the female.
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oxytocin--uterine contraction, milk ejection
prolactin--supresses FSH - name two different parts of the male reproductive system and explain the function of each.
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Testes--produce sperm and testosterone
Seminal vesicles--feeds sperm - Name two different parts of the female reproductive system and explain the functions of each.
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Ovaries--egg maturation occurs here, releases estrogen and progesterone
Fallopian tubes--where fertilization of the egg takes place - What is happening during puberty?
- Male and female reproductive glands become functional
- Explain the function of pubic hair.
- traps pheremones
- Name and explain briefly two disorders of the reproductive system in males or females
- prostate cancer, amenorrhea
- If a male rat is castrated one week after birth, then an ovary is implanted later in life, will that ovary show signs of activity?
- No, because the crucial period of one week has passed and he is already a male. If it had been done immediately after birth, then he would be female and the ovary would function
- Name two symptoms that you might expect to see if someone has myxedema.
- Low BMR, sensitivity to cold, easily fatigued
- Thyroglobulin is a thyroid protein containing a very special amino acid. THe name of that amino acid is _____.
- Thyroxine (T4)
- Triiodothymine is the name given to the active hormone of the thyroid gland. What is its relationship to thyroxine?
- T4 is long acting, can be converted to T3 by loss of iodine.
- What does T3 actually do?
- Acts directly on genetic material to increase mitochondrial activity, which causes an increase in ATP
- What is simple goiter and how can it be cured?
- swelling in thyroid gland to grab on to iodine, give iodine in the diet
- President and Mrs. Bush both had Graves disease. What was done to treat them, and what is their continuing need for treatment?
- Have thryoid killed with large doses of radioactive iodine, treat for hypothyroidism by giving T4
- Whta condition is associated with exopthalmia, and what is another symptom that is usually associated with this disease?
- Hyperthyroidism, excitablity and high BMR
- What effect does T3 or T4 have on the pituitary gland?
- inhibits production of TSH (Thyroid Stimulating Hormone)
- What effect does T3 or T4 have on the hypothalamus?
- inhibits TSH RF
- How does the external environment affect the levels of T4 and T3?
- Throug the feedback loop, T3 and 4 are set in hypothalamus, responding to external temperature; hot=less, cold=more
- How are tumors of the thyroid gland most likely to arise?
- accumulation of radioactive iodine, through foodchain or excessive x-rays
- Tetany is a condition involving muscle spasms and eventually death. What ionic component of the blood will be low when this disease occurs?
- calcium ion
- A hormone will be low if an animal has tetany. The name of that hormone is ______.
- parathormone
- How does parathormone effect the activity if osteoclasts?
- increases activity so bone dissolves and calcium increases in blood
- An osteoblast is a bone cell whose activity is controlled by a hormone called ______.
- calcitonin
- How does calcitonin affect the activity of the osteoblast?
- increases, causes a build up of bone and decrease of calcium in blood
- Calcium blood level is carefully controlled by parathyroid hormone, but that blood level is also affected by a completely different hormone. That hormone is called _______.
- Vitamin D
- In the absence of Vitamin D, a person suffers from a disease called _______, common in Victorian times.
- Rickets
- Hyperthyroidism is a very common syndrome. Among what group of people is it usually found?
- postmenopausal women
- Parathormone is antagonized by a completely different hormone, namely a sex hormone. What is the result of changing levels of that hormone?
- estrogen, as it decreases parathormone increases, so calcium is broken down from bones and they become weaker.
- Parathormone level is controlled in a very simple manner. Diagram this control system
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Parathormone <-----
----->Calcium in blood - The pancreas is an organ which does two completely different things. List what that involves.
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Exocrine function--produce enzymes, bicarbonate for digestion
Endocrine function--insulin and glucagon (produced in islands of langerhans) - High blood sugar in associated with the disease commonly called ______.
- diabetes
- Sugar is found in the urine of a diabetic. This is because ________.
- Sugar is not getting into body cells so it overflows into the urine
- Incomplete metabolism of fat, in particular, in the diabetic leads to accumulation and elimination of a group of compounds with a fairly distinctive odor. These are called ________.
- Ketone bodies
- The rule for insulin production is that insulin tracks glucose. Explain what that means in real life and in terms of the control of insulin production.
- Glucose and insulin levels fluctuate, each eventuallu returning to fasting rate
- A crude extract of the pancreas raises blood sugar, the opposite of what you might expect. What is the explanation for this contradictory result?
- extract contains a 2nd hormone called glucagon, which raises blood sugar
- Glucagon raises blood sugar, insulin lowers it. Present an alternative theory to explain diabetes based on that finding.
- diabetes could be due to excess glucagon, and not too little insulin
- An alternative theory for diabetes is that it is caused by excess production of glucagon. How could you lower the amount of glucagon, using another hormone and how does this work?
- Somatostatin, antagonizes glucagon, but is has lots of side effects
- Diabetes may in some instances be associated with a virus infection early in life. Explain the connection.
- Infection will destroy part of the beta cells in the islands of langerhans, and immune system thinks the cells are foreign and destroys them (autoimmune disease)
- There is a genetic connection for diabetes. What will be the effect, in say, another 1000 years and why?
- There will be a gradual increase in the number of diabetics because most diabetics live well past the reproductive age and pass it on to their children
- Removal of the adrenal gland is fatal. Which part of the gland is responsible for this effect?
- Cortex
- The medulla of the adrenal gland arises embryologically from a tissue called the neural crest. Explain then what the medulla does.
- produces adrenaline, prolonging action of sympathetic nervous system
- The cortex of the adrenal produces testosterone. Explain why there is conspicuous evidence of that in a segment of the population.
- In females, testosterone is overshadowed by estrogen before menopause. At menopause, when estrogen drops, there is an increase in masculinization
- What is the stress hormone of the adrenal and how is it controlled?
- Cortisol
- Aldosterone is the most important hormone of the adrenal. What does it do, and what does characteristically wrong in its absence?
- Necessary for reabsorption of sodium in kidney. Without it, the Sodium/potassium ratio is altered. Too much Potassium results in death
- What characteristic symptoms are seen if the adrenal glands are underfunctioning?
- weight loss, plasma volume decreases, darkening of cartiledge
- Name one highly distinctive symptom associated with Cushing's disease.
- moon-shaped face, masculinization
- What is a circadian rhythym?
- about a day (25 hrs.), fluctuation of different body components
- The pineal gland produces melatonin. What is the major effect of this hormone, and how does that relate to the development of a human being?
- imposes circadian rhythym, antagonizes sex hormones
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Give the results of the following two experiments, along with a brief explanation.
Mouse + skin graft--
Mouse-Thymys + skin graft-- -
1. rejects because the body doesn't like anybody else
2. accepts because the thymus is required to mature T-cells - A hormone from the thymus gland is vital for the maturation of a group of white blood cells. What is the name of the hormone and what are the white blood cells called?
- thymosin, T-cells
- The AIDS virus attacks helper T-cells specifically. Give two properties of these cells which are thus affected by this infection.
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1. increase number of macrophages and lymphokines
2. increase production of interferons - The immune system is delicately balanced to repel invaders, but not anything else. What type of T-cell is specifically involved in the latter function, and what happens if that mechanism goes awry?
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T-cell type: supressor T-cells
Consequence: autoimmune disease