Phys II Final
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Questions and Answers

What are the energy sources stored in skeletal muscle?

  • Glucose and Pyruvate
  • Glycogen and Lactate
  • Fatty Acids and Ketones
  • ATP and Phosphocreatine (correct)

    • What is the name of the protein found in muscle tissue that can bind oxygen?

  • Hemoglobin
  • Myosin
  • Myoglobin (correct)
  • Actin

    • In addition to ATP, what other high-energy molecule can be used to power high-intensity muscle activity?

  • Creatine
  • Glycogen
  • ADP
  • Phosphocreatine (correct)

    • What is the storage form of glucose in the muscle?

    <p>Glycogen</p> Signup and view all the answers

    Which part of the energy continuum is primarily used for a 50-yard dash?

    <p>Phosphagen System</p> Signup and view all the answers

    The source of ATP for a given activity is dependent on which two factors?

    <p>Intensity and duration of the activity</p> Signup and view all the answers

    Which energy system would an athlete primarily use during a marathon?

    <p>Aerobic Metabolism</p> Signup and view all the answers

    What type of metabolism yields the most energy?

    <p>Aerobic Metabolism</p> Signup and view all the answers

    In the absence of adequate carbohydrates in the body, what is the metabolic fate of triglycerides?

    <p>They are converted to fatty acids and ketones</p> Signup and view all the answers

    Which of the following activities rely on ATP and creatine phosphate?

    <p>Weightlifting</p> Signup and view all the answers

    What is a limitation of the ATP-PC system?

    <p>It provides energy for only a few seconds</p> Signup and view all the answers

    Which of the following is a possible side effect of creatine monohydrate supplementation?

    <p>Gastrointestinal discomfort</p> Signup and view all the answers

    Where in the muscle cell does anaerobic glycolysis occur?

    <p>Cytoplasm</p> Signup and view all the answers

    How much energy (ATP) can be produced from one molecule of glucose using anaerobic glycolysis?

    <p>2 ATP</p> Signup and view all the answers

    Without adequate oxygen, what is the fate of pyruvate?

    <p>It is converted to lactic acid</p> Signup and view all the answers

    What is the oxygen deficit?

    <p>The difference between oxygen demand and supply during exercise</p> Signup and view all the answers

    What eventually happens to the lactic acid produced during exercise?

    <p>It is converted back to pyruvate and used for energy</p> Signup and view all the answers

    What is the Cori cycle?

    <p>The conversion of lactic acid back to glucose in the liver</p> Signup and view all the answers

    In a working muscle cell, what organelle is responsible for aerobic metabolism?

    <p>Mitochondria</p> Signup and view all the answers

    What are the waste products of aerobic metabolism?

    <p>CO2 and water</p> Signup and view all the answers

    Under normal dietary conditions, why can't muscles rely solely on triglycerides as an energy source?

    <p>Complete oxidation of fats requires carbohydrates for the Krebs cycle</p> Signup and view all the answers

    What is beta oxidation?

    <p>The process of breaking down fatty acids into acetyl-CoA units</p> Signup and view all the answers

    How does beta oxidation allow fatty acids to be oxidized to produce ATP?

    <p>By converting fatty acids into acetyl-CoA, which enters the Krebs cycle</p> Signup and view all the answers

    What does the phrase 'fats burn in a carbohydrate flame' mean?

    <p>Fats require carbohydrates to be completely oxidized</p> Signup and view all the answers

    What is the physiological phenomenon of 'hitting the wall'?

    <p>The depletion of glycogen stores leading to fatigue</p> Signup and view all the answers

    Name some examples of low carbohydrate states that can lead to ketosis.

    <p>Periods of fasting or starvation</p> Signup and view all the answers

    Which tissues in the body can be adequately fueled by ketones?

    <p>Heart, skeletal muscle, kidneys, and brain</p> Signup and view all the answers

    In what organ does ketogenesis take place?

    <p>Liver</p> Signup and view all the answers

    What are the three ketones formed from acetyl-CoA?

    <p>Acetoacetate, beta-hydroxybutyrate, and acetone</p> Signup and view all the answers

    How does ketosis affect insulin and blood glucose levels?

    <p>Decreases insulin and stabilizes blood glucose levels</p> Signup and view all the answers

    Which of the following can hasten or produce muscle fatigue?

    <p>Dehydration and nutrient depletion</p> Signup and view all the answers

    Muscle fatigue refers to:

    <p>Reduced capacity of a muscle to perform work</p> Signup and view all the answers

    Which muscle fiber type is best suited for endurance?

    <p>Type I</p> Signup and view all the answers

    Which muscle fiber type will hypertrophy with resistance training?

    <p>Type IIb</p> Signup and view all the answers

    What are the physiological features of Type I muscle fibers?

    <p>Slow contraction, high fatigue resistance, aerobic, small diameter</p> Signup and view all the answers

    Which dominant energy system is utilized by Type IIb fibers?

    <p>Anaerobic glycolysis</p> Signup and view all the answers

    How does ventilation change at the onset of exercise?

    <p>Increases rapidly</p> Signup and view all the answers

    What is the mechanism that triggers the change in ventilation at the onset of exercise?

    <p>Neural input from the brain, chemical changes in the blood, and proprioceptive feedback from muscles</p> Signup and view all the answers

    How do the ventilatory changes of well-trained athletes compare with those of untrained individuals?

    <p>Well-trained athletes have more efficient ventilatory responses</p> Signup and view all the answers

    During aerobic exercise, how does ventilation change 4–6 minutes after the onset?

    <p>Increases to meet the steady-state demands of the activity</p> Signup and view all the answers

    What is the anaerobic threshold?

    <p>The point during intense exercise at which lactate starts to accumulate in the blood</p> Signup and view all the answers

    If exercise exceeds the anaerobic threshold, what changes can be observed in the blood?

    <p>Increase in blood lactate levels and hydrogen ions, leading to a drop in pH</p> Signup and view all the answers

    How does the increase in blood lactate and hydrogen ions lead to a change in ventilation?

    <p>It stimulates chemoreceptors, leading to increased ventilation to expel CO2 and restore pH balance</p> Signup and view all the answers

    Which function is NOT a primary role of the female reproductive system?

    <p>Regulation of blood pressure</p> Signup and view all the answers

    What is the final stage of ova maturation?

    <p>Corpus albicans</p> Signup and view all the answers

    Which phase is NOT part of the uterine cycle?

    <p>Luteal phase</p> Signup and view all the answers

    Which phase of the female sex act is regulated by the autonomic nervous system?

    <p>All of the above</p> Signup and view all the answers

    Which hormone does NOT play a significant role in the female reproductive cycle?

    <p>Testosterone</p> Signup and view all the answers

    Which hormone stimulates the anterior pituitary to release FSH and LH?

    <p>GnRH</p> Signup and view all the answers

    What is the primary function of FSH in the ovarian cycle?

    <p>Stimulate follicular growth and maturation</p> Signup and view all the answers

    What triggers the LH surge in the ovarian cycle?

    <p>High levels of estrogen</p> Signup and view all the answers

    What occurs during the follicular phase of the ovarian cycle?

    <p>Maturation of ovarian follicles</p> Signup and view all the answers

    What event marks the end of the follicular phase?

    <p>Ovulation</p> Signup and view all the answers

    What hormone is primarily responsible for the luteal phase of the ovarian cycle?

    <p>Progesterone</p> Signup and view all the answers

    Which estrogen is the most potent and abundant in females?

    <p>Estradiol</p> Signup and view all the answers

    What is the primary role of progesterone in the female reproductive system?

    <p>Prepare the uterus for pregnancy</p> Signup and view all the answers

    Which phase of the uterine cycle involves shedding of the uterine lining?

    <p>Menstrual phase</p> Signup and view all the answers

    During which phase does the endometrium rebuild itself?

    <p>Proliferative phase</p> Signup and view all the answers

    What initiates the early follicular phase of the ovarian cycle?

    <p>Increase in FSH</p> Signup and view all the answers

    What hormonal change triggers ovulation?

    <p>Surge in LH</p> Signup and view all the answers

    What is the primary hormone secreted by the corpus luteum during the luteal phase?

    <p>Progesterone</p> Signup and view all the answers

    Which phase of the female sexual act is characterized by rhythmic contractions of the pelvic muscles?

    <p>Orgasm</p> Signup and view all the answers

    Which hormone is known to enhance libido in females?

    <p>Testosterone</p> Signup and view all the answers

    What is the typical viability period of the ovum?

    <p>12-24 hours</p> Signup and view all the answers

    What is the primary mechanism of action for oral contraceptives?

    <p>Inhibiting ovulation by suppressing FSH and LH release</p> Signup and view all the answers

    Which form of contraception has the lowest failure rate with typical use?

    <p>Hormonal IUD</p> Signup and view all the answers

    What are the energy sources stored in skeletal muscle?

    <p>Fatty Acids and Ketones</p> Signup and view all the answers

    What is the name of the protein found in muscle tissue that can bind oxygen?

    <p>Myoglobin</p> Signup and view all the answers

    In addition to ATP, what other high-energy molecule can be used to power high-intensity muscle activity?

    <p>ADP</p> Signup and view all the answers

    What is the storage form of glucose in the muscle?

    <p>Lactate</p> Signup and view all the answers

    Which part of the energy continuum is primarily used for a 50-yard dash?

    <p>Phosphagen System</p> Signup and view all the answers

    The source of ATP for a given activity is dependent on which two factors?

    <p>Muscle fiber type and hydration status</p> Signup and view all the answers

    Which energy system would an athlete primarily use during a marathon?

    <p>Anaerobic Glycolysis</p> Signup and view all the answers

    What type of metabolism yields the most energy?

    <p>Aerobic Metabolism</p> Signup and view all the answers

    In the absence of adequate carbohydrates in the body, what is the metabolic fate of triglycerides?

    <p>They are converted to glucose</p> Signup and view all the answers

    Which of the following activities rely on ATP and creatine phosphate?

    <p>Weightlifting</p> Signup and view all the answers

    What is a limitation of the ATP-PC system?

    <p>It produces lactic acid</p> Signup and view all the answers

    Which of the following is a possible side effect of creatine monohydrate supplementation?

    <p>Gastrointestinal discomfort</p> Signup and view all the answers

    Where in the muscle cell does anaerobic glycolysis occur?

    <p>Mitochondria</p> Signup and view all the answers

    How much energy (ATP) can be produced from one molecule of glucose using anaerobic glycolysis?

    <p>2 ATP</p> Signup and view all the answers

    Without adequate oxygen, what is the fate of pyruvate?

    <p>It is converted to glycogen</p> Signup and view all the answers

    What is the oxygen deficit?

    <p>The difference between oxygen demand and supply during exercise</p> Signup and view all the answers

    What eventually happens to the lactic acid produced during exercise?

    <p>It remains in the muscles</p> Signup and view all the answers

    What is the Cori cycle?

    <p>The process of converting glucose to glycogen</p> Signup and view all the answers

    In a working muscle cell, what organelle is responsible for aerobic metabolism?

    <p>Golgi Apparatus</p> Signup and view all the answers

    What are the waste products of aerobic metabolism?

    <p>Lactate and CO2</p> Signup and view all the answers

    Under normal dietary conditions, why can't muscles rely solely on triglycerides as an energy source?

    <p>Triglycerides are not stored in muscle cells</p> Signup and view all the answers

    What is beta oxidation?

    <p>The process of breaking down fatty acids into acetyl-CoA units</p> Signup and view all the answers

    How does beta oxidation allow fatty acids to be oxidized to produce ATP?

    <p>By converting fatty acids into lactic acid</p> Signup and view all the answers

    What does the phrase 'fats burn in a carbohydrate flame' mean?

    <p>Fats require carbohydrates to be completely oxidized</p> Signup and view all the answers

    What is the physiological phenomenon of 'hitting the wall'?

    <p>A sudden increase in energy levels</p> Signup and view all the answers

    Name some examples of low carbohydrate states that can lead to ketosis.

    <p>Protein supplementation</p> Signup and view all the answers

    Which tissues in the body can be adequately fueled by ketones?

    <p>Heart, skeletal muscle, kidneys, and brain</p> Signup and view all the answers

    In what organ does ketogenesis take place?

    <p>Liver</p> Signup and view all the answers

    What are the three ketones formed from acetyl-CoA?

    <p>Acetoacetate, beta-hydroxybutyrate, and acetone</p> Signup and view all the answers

    How does ketosis affect insulin and blood glucose levels?

    <p>Increases insulin and blood glucose levels</p> Signup and view all the answers

    Which of the following can hasten or produce muscle fatigue?

    <p>Increased oxygen supply</p> Signup and view all the answers

    Muscle fatigue refers to:

    <p>Reduced capacity of a muscle to perform work</p> Signup and view all the answers

    Which muscle fiber type is best suited for endurance?

    <p>Type I</p> Signup and view all the answers

    Which muscle fiber type will hypertrophy with resistance training?

    <p>Type IIb</p> Signup and view all the answers

    What are the physiological features of Type I muscle fibers?

    <p>Fast contraction, high fatigue resistance, anaerobic, large diameter</p> Signup and view all the answers

    Which dominant energy system is utilized by Type IIb fibers?

    <p>Aerobic metabolism</p> Signup and view all the answers

    How does ventilation change at the onset of exercise?

    <p>Decreases gradually</p> Signup and view all the answers

    What is the mechanism that triggers the change in ventilation at the onset of exercise?

    <p>Increased blood glucose levels</p> Signup and view all the answers

    How do the ventilatory changes of well-trained athletes compare with those of untrained individuals?

    <p>There is no difference between well-trained athletes and untrained individuals</p> Signup and view all the answers

    During aerobic exercise, how does ventilation change 4–6 minutes after the onset?

    <p>Decreases gradually</p> Signup and view all the answers

    What is the anaerobic threshold?

    <p>The point during exercise when oxygen consumption is at its maximum</p> Signup and view all the answers

    If exercise exceeds the anaerobic threshold, what changes can be observed in the blood?

    <p>Decrease in blood lactate levels</p> Signup and view all the answers

    How does the increase in blood lactate and hydrogen ions lead to a change in ventilation?

    <p>It stimulates chemoreceptors, leading to increased ventilation to expel CO2 and restore pH balance</p> Signup and view all the answers

    What is the primary function of the testes in males?

    <p>Produce sperm and secrete testosterone</p> Signup and view all the answers

    What structures are included in the internal genital tract of males?

    <p>Epididymis, vas deferens, seminal vesicles, and prostate</p> Signup and view all the answers

    Which structures are considered external genitalia in females?

    <p>Labia majora, labia minora, clitoris, and vestibule</p> Signup and view all the answers

    What determines genetic sex?

    <p>Sex chromosomes (XY for males and XX for females)</p> Signup and view all the answers

    Gonadal sex is determined by the presence of:

    <p>Testes in males and ovaries in females</p> Signup and view all the answers

    Phenotypic sex is influenced by:

    <p>Hormonal output from the gonads (testosterone in males and estrogen in females)</p> Signup and view all the answers

    During the first 5 weeks of gestational life, the gonads are:

    <p>Indifferent or bipotential</p> Signup and view all the answers

    At what gestational age do the testes begin to develop in genetic males?

    <p>Week 6 to 7</p> Signup and view all the answers

    At what gestational age do the ovaries begin to develop in genetic females?

    <p>Week 9</p> Signup and view all the answers

    What structures determine gonadal sex?

    <p>Presence of testes in males and ovaries in females</p> Signup and view all the answers

    In males, what are the germ cells and steroid hormone-secreting cells?

    <p>Spermatogonia and Leydig cells</p> Signup and view all the answers

    What structures determine phenotypic sex?

    <p>Development of the internal genital tract and external genitalia</p> Signup and view all the answers

    Which hormone stimulates the growth and differentiation of the Wolffian ducts?

    <p>Testosterone</p> Signup and view all the answers

    What hormone causes atrophy of the Müllerian ducts?

    <p>Anti-Müllerian hormone (AMH)</p> Signup and view all the answers

    The Wolffian ducts give rise to which structures in males?

    <p>Epididymis, vas deferens, seminal vesicles, and ejaculatory ducts</p> Signup and view all the answers

    What hormone is secreted by the hypothalamus to regulate reproductive function?

    <p>GnRH</p> Signup and view all the answers

    What hormones are secreted by the anterior pituitary in response to GnRH?

    <p>FSH and LH</p> Signup and view all the answers

    Which cells in the testes are stimulated by LH to produce testosterone?

    <p>Leydig cells</p> Signup and view all the answers

    Which hormones are required for the development of the male phenotype?

    <p>Testosterone and Anti-Müllerian Hormone (AMH)</p> Signup and view all the answers

    What is the function of the epididymis?

    <p>Store and mature sperm</p> Signup and view all the answers

    What is the role of the seminal vesicles in the male reproductive system?

    <p>Produce seminal fluid to nourish and transport sperm</p> Signup and view all the answers

    Why do the testes reside outside the abdominal cavity in the scrotum?

    <p>To maintain a temperature slightly lower than body temperature, which is optimal for sperm development and maturation</p> Signup and view all the answers

    What is the primary function of the seminiferous tubules?

    <p>Germination, maturation, and transportation of sperm cells</p> Signup and view all the answers

    What cells are found inside the seminiferous tubules and provide support to developing sperm cells?

    <p>Sertoli cells</p> Signup and view all the answers

    What is the role of Leydig cells in the testes?

    <p>Produce testosterone</p> Signup and view all the answers

    What is the function of the blood-testis barrier?

    <p>Prevent the immune system from attacking developing sperm cells</p> Signup and view all the answers

    What hormone do Sertoli cells secrete to inhibit FSH production?

    <p>Inhibin</p> Signup and view all the answers

    Why are Sertoli cells referred to as 'nurse cells'?

    <p>They provide structural and nutritional support to developing sperm cells</p> Signup and view all the answers

    What protein do Sertoli cells produce to concentrate testosterone within the seminiferous tubules?

    <p>Androgen-binding protein (ABP)</p> Signup and view all the answers

    What hormone do Sertoli cells secrete during embryonic development to prevent the formation of female reproductive structures?

    <p>Anti-Müllerian hormone (AMH)</p> Signup and view all the answers

    Which hormone stimulates Leydig cells to produce testosterone?

    <p>LH</p> Signup and view all the answers

    What is the role of GnRH in the hypothalamic-pituitary axis?

    <p>Stimulate the anterior pituitary to secrete FSH and LH</p> Signup and view all the answers

    What enzyme converts testosterone to dihydrotestosterone (DHT)?

    <p>5-alpha-reductase</p> Signup and view all the answers

    What is the role of sex hormone-binding globulin (SHBG)?

    <p>Bind to sex hormones like testosterone, regulating their bioavailability and transport in the bloodstream</p> Signup and view all the answers

    Which hormone is converted to estradiol by the enzyme aromatase?

    <p>Testosterone</p> Signup and view all the answers

    Which androgen is responsible for inducing and maintaining secondary sex characteristics in males?

    <p>Testosterone</p> Signup and view all the answers

    What are the effects of dihydrotestosterone (DHT) at puberty in males?

    <p>Inducing and maintaining secondary sex characteristics, such as facial and body hair, deepening of the voice, and development of the prostate and seminal vesicles</p> Signup and view all the answers

    What is the role of 17 beta-estradiol in mature sperm cells?

    <p>Optimize spermatogenesis and sperm function</p> Signup and view all the answers

    Which structures are part of the male reproductive tract?

    <p>Epididymis, vas deferens, ejaculatory duct, urethra, and distal urinary tract</p> Signup and view all the answers

    Which nervous system is primarily active during erection?

    <p>Parasympathetic nervous system</p> Signup and view all the answers

    Which phase of the male sexual act is controlled by the sympathetic nervous system?

    <p>Emission and ejaculation</p> Signup and view all the answers

    During the menses phase of the menstrual cycle, the levels of LH and FSH are:

    <p>Low</p> Signup and view all the answers

    What triggers the increase in LH and FSH during the proliferative phase?

    <p>Follicular estrogen</p> Signup and view all the answers

    What event is triggered by the peak of LH?

    <p>Ovulation</p> Signup and view all the answers

    What happens to LH and FSH levels during the secretory phase with no fertilization?

    <p>They decline</p> Signup and view all the answers

    What hormone is primarily responsible for the negative feedback during the secretory phase?

    <p>Progesterone</p> Signup and view all the answers

    What hormone significantly suppresses the maternal hypothalamic-pituitary-ovarian axis during pregnancy?

    <p>Progesterone</p> Signup and view all the answers

    What type of feedback system involves oxytocin during labor?

    <p>Positive feedback</p> Signup and view all the answers

    When does the trophoblast begin secreting human chorionic gonadotropin (HCG)?

    <p>8 days after ovulation</p> Signup and view all the answers

    What is the role of HCG in early pregnancy?

    <p>Maintain the corpus luteum</p> Signup and view all the answers

    How does estrogen affect oxytocin receptors toward the end of gestation?

    <p>Up-regulates them</p> Signup and view all the answers

    What is the main source of estrogen and progesterone production in the second and third trimesters of pregnancy?

    <p>Placenta</p> Signup and view all the answers

    What is the effect of estrogen on uterine contractility?

    <p>Increases contractility</p> Signup and view all the answers

    What hormone stimulates milk production by inducing the synthesis of lactose, casein, and lipids?

    <p>Prolactin</p> Signup and view all the answers

    What happens to the corpus luteum around 16-20 weeks of gestation?

    <p>It resolves</p> Signup and view all the answers

    What marks the time of highest progesterone output by the corpus luteum?

    <p>Implantation</p> Signup and view all the answers

    What structural change occurs in the uterine endometrium during pregnancy?

    <p>It thickens and becomes the decidua</p> Signup and view all the answers

    Which hormone's levels peak at around gestational week 9 and then decline?

    <p>HCG</p> Signup and view all the answers

    What does the blastocyst contribute to during pregnancy?

    <p>The fetal portion of the placenta</p> Signup and view all the answers

    What specialized layer forms in the endometrium under the influence of progesterone?

    <p>Decidua</p> Signup and view all the answers

    What process occurs in the placenta involving cholesterol during late pregnancy?

    <p>Conversion to pregnenolone</p> Signup and view all the answers

    What is the main function of the placenta during pregnancy?

    <p>Serve as a transport epithelium and an endocrine gland</p> Signup and view all the answers

    Where is DHEA-sulfate hydroxylated to 16-OH DHEA-sulfate during pregnancy?

    <p>Fetal liver</p> Signup and view all the answers

    What hormone is produced by the placenta from 16-OH DHEA-sulfate?

    <p>Estriol</p> Signup and view all the answers

    Which hormone's production shifts from the corpus luteum to the placenta in the second trimester?

    <p>Progesterone</p> Signup and view all the answers

    What triggers the formation of the corpus luteum?

    <p>Ovulation induced by LH surge</p> Signup and view all the answers

    What happens to the uterine endometrium if fertilization does not occur?

    <p>It undergoes necrosis and is eliminated</p> Signup and view all the answers

    During which phase does the corpus luteum form?

    <p>Secretory</p> Signup and view all the answers

    What is the primary role of the corpus luteum in early pregnancy?

    <p>Produce large amounts of progesterone and some estrogen</p> Signup and view all the answers

    What happens to estrogen levels during the secretory phase without fertilization?

    <p>They decline</p> Signup and view all the answers

    Which structure forms after the corpus luteum degenerates?

    <p>Corpus albicans</p> Signup and view all the answers

    What hormone increases due to the action of LH from the corpus luteum?

    <p>Progesterone</p> Signup and view all the answers

    What is the state of LH and FSH levels during the menses phase?

    <p>Low</p> Signup and view all the answers

    What is the primary role of estrogen during the proliferative phase?

    <p>Induce rapid proliferation of the uterine endometrium</p> Signup and view all the answers

    What happens to progesterone levels if fertilization occurs?

    <p>They increase steadily</p> Signup and view all the answers

    Which phase is characterized by the formation of the placenta?

    <p>Secretory Pregnancy</p> Signup and view all the answers

    During which trimester does the placenta assume the role of steroid hormone production?

    <p>Second trimester</p> Signup and view all the answers

    What happens to new follicle maturation during pregnancy?

    <p>It is suppressed</p> Signup and view all the answers

    What significant role does the placenta play in late pregnancy regarding progesterone?

    <p>It converts cholesterol to pregnenolone</p> Signup and view all the answers

    During the menses phase of the menstrual cycle, the levels of LH and FSH are:

    <p>Low</p> Signup and view all the answers

    What triggers the increase in LH and FSH during the proliferative phase?

    <p>Follicular estrogen</p> Signup and view all the answers

    What event is triggered by the peak of LH?

    <p>Ovulation</p> Signup and view all the answers

    What happens to LH and FSH levels during the secretory phase with no fertilization?

    <p>They decline</p> Signup and view all the answers

    What hormone is primarily responsible for the negative feedback during the secretory phase?

    <p>Progesterone</p> Signup and view all the answers

    What hormone significantly suppresses the maternal hypothalamic-pituitary-ovarian axis during pregnancy?

    <p>Progesterone</p> Signup and view all the answers

    When does the trophoblast begin secreting human chorionic gonadotropin (HCG)?

    <p>8 days after ovulation</p> Signup and view all the answers

    What is the role of HCG in early pregnancy?

    <p>Maintain the corpus luteum</p> Signup and view all the answers

    What is the main source of estrogen and progesterone production in the second and third trimesters of pregnancy?

    <p>Placenta</p> Signup and view all the answers

    What happens to the corpus luteum around 16-20 weeks of gestation?

    <p>It resolves</p> Signup and view all the answers

    What structural change occurs in the uterine endometrium during pregnancy?

    <p>It thickens and becomes the decidua</p> Signup and view all the answers

    Which hormone's levels peak at around gestational week 9 and then decline?

    <p>HCG</p> Signup and view all the answers

    What process occurs in the placenta involving cholesterol during late pregnancy?

    <p>Conversion to pregnenolone</p> Signup and view all the answers

    Where is DHEA-sulfate hydroxylated to 16-OH DHEA-sulfate during pregnancy?

    <p>Fetal liver</p> Signup and view all the answers

    What hormone is produced by the placenta from 16-OH DHEA-sulfate?

    <p>Estriol</p> Signup and view all the answers

    Which hormone's production shifts from the corpus luteum to the placenta in the second trimester?

    <p>Progesterone</p> Signup and view all the answers

    What triggers the formation of the corpus luteum?

    <p>Ovulation induced by LH surge</p> Signup and view all the answers

    What happens to the uterine endometrium if fertilization does not occur?

    <p>It undergoes necrosis and is eliminated</p> Signup and view all the answers

    During which phase does the corpus luteum form?

    <p>Secretory</p> Signup and view all the answers

    What is the primary role of the corpus luteum in early pregnancy?

    <p>Produce large amounts of progesterone and some estrogen</p> Signup and view all the answers

    What happens to estrogen levels during the secretory phase without fertilization?

    <p>They decline</p> Signup and view all the answers

    Which structure forms after the corpus luteum degenerates?

    <p>Corpus albicans</p> Signup and view all the answers

    What hormone increases due to the action of LH from the corpus luteum?

    <p>Progesterone</p> Signup and view all the answers

    What is the state of LH and FSH levels during the menses phase?

    <p>Low</p> Signup and view all the answers

    What is the primary role of estrogen during the proliferative phase?

    <p>Induce rapid proliferation of the uterine endometrium</p> Signup and view all the answers

    What happens to progesterone levels if fertilization occurs?

    <p>They increase steadily</p> Signup and view all the answers

    Which phase is characterized by the formation of the placenta?

    <p>Secretory Pregnancy</p> Signup and view all the answers

    During which trimester does the placenta assume the role of steroid hormone production?

    <p>Second trimester</p> Signup and view all the answers

    What happens to new follicle maturation during pregnancy?

    <p>It is suppressed</p> Signup and view all the answers

    What significant role does the placenta play in late pregnancy regarding progesterone?

    <p>It converts cholesterol to pregnenolone</p> Signup and view all the answers

    What hormone initiates the ovarian cycle by stimulating the anterior pituitary?

    <p>GnRH</p> Signup and view all the answers

    What is the primary function of FSH and LH during the ovarian cycle?

    <p>Stimulate follicular development</p> Signup and view all the answers

    What effect do inhibin and low levels of estrogen have on the hypothalamus and anterior pituitary?

    <p>Negative feedback</p> Signup and view all the answers

    What hormone assists in the development of the dominant ovarian follicle?

    <p>Estrogen</p> Signup and view all the answers

    What triggers the LH surge that induces ovulation?

    <p>High levels of estrogen</p> Signup and view all the answers

    What structure forms from the ovulated follicle?

    <p>Corpus luteum</p> Signup and view all the answers

    What does the corpus luteum secrete after ovulation?

    <p>Progesterone, estrogen, and inhibin</p> Signup and view all the answers

    What happens to the corpus luteum if the oocyte is not fertilized?

    <p>It degenerates in 10 to 13 days</p> Signup and view all the answers

    What restarts the ovarian cycle if the oocyte is not fertilized?

    <p>Drop in progesterone, estrogen, and inhibin</p> Signup and view all the answers

    What hormones stimulate the growth and development of breasts during pregnancy?

    <p>Estrogen and progesterone</p> Signup and view all the answers

    What hormone is primarily responsible for milk production?

    <p>Prolactin</p> Signup and view all the answers

    What blocks the action of prolactin on the breast during pregnancy?

    <p>High levels of estrogen and progesterone</p> Signup and view all the answers

    What triggers the secretion of prolactin during breastfeeding?

    <p>Suckling stimulus</p> Signup and view all the answers

    What effect does dopamine have on prolactin secretion in non-pregnant individuals?

    <p>Inhibits prolactin secretion</p> Signup and view all the answers

    What hormone is responsible for milk ejection?

    <p>Oxytocin</p> Signup and view all the answers

    What stimulates oxytocin secretion from the posterior pituitary?

    <p>Suckling and sensory stimuli</p> Signup and view all the answers

    How does breastfeeding affect ovulation?

    <p>It inhibits ovulation</p> Signup and view all the answers

    What is the 'tend-and-befriend' response in females attributed to?

    <p>High levels of oxytocin</p> Signup and view all the answers

    What hormone helps to regulate the inhibitory effect of dopamine on prolactin?

    <p>Prolactin itself</p> Signup and view all the answers

    What hormone is produced by the trophoblast approximately 8 days after ovulation?

    <p>Human Chorionic Gonadotropin (HCG)</p> Signup and view all the answers

    What is the primary role of HCG in early pregnancy?

    <p>Maintain the corpus luteum</p> Signup and view all the answers

    What is the source of steroid hormones during the first trimester of pregnancy?

    <p>Corpus luteum</p> Signup and view all the answers

    How is estriol synthesized during pregnancy?

    <p>Pregnenolone (placenta) → DHEA-S (fetal adrenals) → Estriol (placenta)</p> Signup and view all the answers

    What triggers the production of fetal cortisol near term?

    <p>Activation of fetal hypothalamic-pituitary-adrenal axis</p> Signup and view all the answers

    What is the effect of fetal cortisol on the uterus?

    <p>Increases sensitivity to contractile stimuli</p> Signup and view all the answers

    What hormone increases uterine contractility by increasing intracellular calcium concentration in smooth muscle?

    <p>Prostaglandins</p> Signup and view all the answers

    What triggers the release of oxytocin during labor?

    <p>Stretch of the cervix</p> Signup and view all the answers

    Study Notes

    Energy Sources

    • Skeletal muscle stores energy primarily in the forms of ATP and phosphocreatine.
    • Myoglobin is the protein in muscle tissue that binds oxygen, essential for aerobic metabolism.
    • Phosphocreatine serves as a high-energy molecule to power intense muscle activity alongside ATP.
    • Glycogen is the storage form of glucose in muscle, providing a readily available energy source.

    Energy Continuum

    • For short bursts of energy like a 50-yard dash, the phosphagen system is predominantly used.
    • The source of ATP during activity is influenced by both intensity and duration.
    • Aerobic metabolism is utilized primarily by athletes during long-distance events, such as marathons.
    • The highest energy yield comes from aerobic metabolism, making it the most efficient system.
    • In low carbohydrate conditions, triglycerides are transformed into fatty acids and ketones for energy.

    Anaerobic Glycolysis

    • Anaerobic glycolysis occurs in the cytoplasm of muscle cells.
    • It produces 2 ATP from one glucose molecule.
    • In the absence of sufficient oxygen, pyruvate is converted into lactic acid.
    • "Oxygen deficit" refers to the difference between oxygen demand and supply during exercise.
    • Lactic acid produced during exercise can be converted back to pyruvate for energy or used in the Cori cycle to regenerate glucose.

    Ketogenesis and Ketosis

    • Ketogenesis occurs in the liver, producing ketones from acetyl-CoA.
    • The main ketones are acetoacetate, beta-hydroxybutyrate, and acetone.
    • Ketosis leads to decreased insulin and stabilized blood glucose levels.
    • Ketones can fuel heart, skeletal muscle, kidneys, and brain.

    Muscle Fatigue and Fiber Types

    • Muscle fatigue results in a reduced capacity of muscles to perform work, often due to dehydration and nutrient depletion.
    • Type I muscle fibers are suited for endurance, demonstrating slow contraction and high fatigue resistance.
    • Type IIb fibers are primarily involved in anaerobic glycolysis and hypertrophy with resistance training.

    Ventilation and Exercise

    • Ventilation increases rapidly at the onset of exercise due to neural input and chemical changes in the blood.
    • Well-trained athletes exhibit more efficient ventilatory responses than untrained individuals.
    • Ventilation adjusts after 4-6 minutes of aerobic exercise to meet steady-state demands.
    • The anaerobic threshold is the point where lactate begins to accumulate in the bloodstream during intense exercise.

    Blood Lactate Response

    • Exceeding the anaerobic threshold results in increased blood lactate levels and hydrogen ions, causing a drop in pH.
    • Increased lactate and hydrogen ions stimulate chemoreceptors, leading to enhanced ventilation to expel CO2 and restore balance.

    Energy Sources

    • Skeletal muscle stores energy primarily in the forms of ATP and phosphocreatine.
    • Myoglobin is the protein in muscle tissue that binds oxygen, essential for aerobic metabolism.
    • Phosphocreatine serves as a high-energy molecule to power intense muscle activity alongside ATP.
    • Glycogen is the storage form of glucose in muscle, providing a readily available energy source.

    Energy Continuum

    • For short bursts of energy like a 50-yard dash, the phosphagen system is predominantly used.
    • The source of ATP during activity is influenced by both intensity and duration.
    • Aerobic metabolism is utilized primarily by athletes during long-distance events, such as marathons.
    • The highest energy yield comes from aerobic metabolism, making it the most efficient system.
    • In low carbohydrate conditions, triglycerides are transformed into fatty acids and ketones for energy.

    Anaerobic Glycolysis

    • Anaerobic glycolysis occurs in the cytoplasm of muscle cells.
    • It produces 2 ATP from one glucose molecule.
    • In the absence of sufficient oxygen, pyruvate is converted into lactic acid.
    • "Oxygen deficit" refers to the difference between oxygen demand and supply during exercise.
    • Lactic acid produced during exercise can be converted back to pyruvate for energy or used in the Cori cycle to regenerate glucose.

    Ketogenesis and Ketosis

    • Ketogenesis occurs in the liver, producing ketones from acetyl-CoA.
    • The main ketones are acetoacetate, beta-hydroxybutyrate, and acetone.
    • Ketosis leads to decreased insulin and stabilized blood glucose levels.
    • Ketones can fuel heart, skeletal muscle, kidneys, and brain.

    Muscle Fatigue and Fiber Types

    • Muscle fatigue results in a reduced capacity of muscles to perform work, often due to dehydration and nutrient depletion.
    • Type I muscle fibers are suited for endurance, demonstrating slow contraction and high fatigue resistance.
    • Type IIb fibers are primarily involved in anaerobic glycolysis and hypertrophy with resistance training.

    Ventilation and Exercise

    • Ventilation increases rapidly at the onset of exercise due to neural input and chemical changes in the blood.
    • Well-trained athletes exhibit more efficient ventilatory responses than untrained individuals.
    • Ventilation adjusts after 4-6 minutes of aerobic exercise to meet steady-state demands.
    • The anaerobic threshold is the point where lactate begins to accumulate in the bloodstream during intense exercise.

    Blood Lactate Response

    • Exceeding the anaerobic threshold results in increased blood lactate levels and hydrogen ions, causing a drop in pH.
    • Increased lactate and hydrogen ions stimulate chemoreceptors, leading to enhanced ventilation to expel CO2 and restore balance.

    Overview of the Female Reproductive System

    • The female reproductive system does not regulate blood pressure; its primary roles include gamete production, preparation for conception, and nourishment after birth.
    • Final stage of ova maturation is the corpus albicans.
    • The luteal phase is not part of the uterine cycle; the three phases are menstrual, proliferative, and secretory.
    • The female sex act's arousal, plateau, and orgasm phases are all regulated by the autonomic nervous system.
    • Testosterone is not a significant hormone in the female reproductive cycle.

    Hormones of the Female Reproductive Cycle

    • GnRH stimulates the anterior pituitary to release FSH and LH.
    • FSH primarily stimulates follicular growth and maturation in the ovarian cycle.
    • High estrogen levels trigger the LH surge crucial for ovulation.

    Ovarian Cycle

    • The follicular phase involves the maturation of ovarian follicles.
    • Ovulation marks the end of the follicular phase.
    • Progesterone is the hormone responsible for the luteal phase of the ovarian cycle.

    Functions of Ovarian Hormones

    • Estradiol is the most potent and abundant estrogen in females.
    • Progesterone prepares the uterus for potential pregnancy.

    Uterine Cycle

    • The menstrual phase involves shedding the uterine lining.
    • The proliferative phase is when the endometrium rebuilds itself.

    Regulation of the Female Cycle

    • The early follicular phase is initiated by an increase in FSH.
    • A surge in LH triggers ovulation.
    • The primary hormone secreted by the corpus luteum during the luteal phase is progesterone.

    Female Sexual Act

    • Orgasm in the female sexual act is characterized by rhythmic contractions of the pelvic muscles.
    • Testosterone enhances libido in females.

    Female Fertility and Birth Control

    • The ovum is viable for 12-24 hours after ovulation.
    • Oral contraceptives primarily inhibit ovulation by suppressing the release of FSH and LH.
    • Hormonal IUDs have the lowest failure rate with typical use among contraceptive methods.

    Components of Sexual Differentiation

    • Testes produce sperm and secrete testosterone, crucial for male reproductive function.
    • The internal male genital tract includes epididymis, vas deferens, seminal vesicles, and prostate.
    • Female external genitalia consist of labia majora, labia minora, clitoris, and vestibule.

    Definitions

    • Genetic sex is determined by sex chromosomes: XY for males and XX for females.
    • Gonadal sex is dictated by the presence of testes in males and ovaries in females.
    • Phenotypic sex results from gonadal hormonal output, specifically testosterone in males and estrogen in females.

    Genetic Sex

    • Gonads are indifferent or bipotential during the first 5 weeks of gestation.
    • Testes begin developing in genetic males around gestational week 6 to 7.
    • Ovaries start to develop in genetic females at gestational week 9.

    Gonadal Sex

    • Gonadal sex is defined by the presence of testes or ovaries.
    • Male germ cells are spermatogonia, while Leydig cells secrete testosterone.

    Phenotypic Sex

    • Phenotypic sex is established through the development of internal genital tract and external genitalia.
    • Testosterone stimulates growth and differentiation of Wolffian ducts.
    • Anti-Müllerian hormone (AMH) causes the atrophy of Müllerian ducts in males, preventing the development of female structures.
    • Wolffian ducts differentiate into male reproductive structures, including epididymis, vas deferens, and seminal vesicles.

    Gonadotropin Secretion and the Hypothalamic-Pituitary Axis

    • Gonadotropin-releasing hormone (GnRH) regulates reproductive function by signaling the anterior pituitary.
    • FSH and LH are secreted by the anterior pituitary in response to GnRH.
    • LH stimulates Leydig cells in the testes to produce testosterone.

    Components of the Male Reproductive System

    • Testosterone and AMH are essential for male phenotype development.
    • The epididymis stores and matures sperm after production.

    Structure of the Testes

    • Testes are located in the scrotum to maintain a lower temperature optimal for sperm development.

    Seminiferous Tubules

    • Seminiferous tubules are responsible for the germination, maturation, and transportation of sperm cells.

    Intratubular Compartment

    • Sertoli cells within seminiferous tubules provide structural and nutritional support to developing sperm.

    Peritubular Compartment

    • Leydig cells produce testosterone, essential for male reproductive functions.

    Role of the Sertoli Cells

    • The blood-testis barrier prevents immune system attacks on developing sperm.
    • Sertoli cells secrete inhibin, which inhibits FSH production, regulating spermatogenesis.
    • Sertoli cells concentrate testosterone using androgen-binding protein (ABP).
    • Anti-Müllerian hormone secretion by Sertoli cells prevents female reproductive structure development.

    Hypothalamic-Pituitary Axis

    • LH is crucial for stimulating testosterone production by Leydig cells.
    • GnRH's primary role is to stimulate the anterior pituitary to release FSH and LH.

    Androgens

    • 5-alpha-reductase converts testosterone to dihydrotestosterone (DHT), which is crucial in male development.
    • Sex hormone-binding globulin (SHBG) binds testosterone, regulating its availability.
    • Testosterone is converted to estradiol by the enzyme aromatase.

    Androgen Actions

    • Testosterone induces and maintains secondary male sex characteristics.
    • DHT causes changes such as facial and body hair growth, deepening voice, and prostate development during puberty.

    Actions of 17 Beta-estradiol

    • 17 beta-estradiol optimizes spermatogenesis and sperm function in mature sperm cells.

    Male Reproductive Tract

    • Structures include epididymis, vas deferens, ejaculatory duct, urethra, and distal urinary tract.

    Male Sexual Act

    • The parasympathetic nervous system primarily controls erection.
    • Emission and ejaculation are regulated by the sympathetic nervous system.

    Hormonal Changes in the Menstrual Cycle

    • LH and FSH levels are low during the menses phase.
    • The proliferative phase sees an increase in LH and FSH triggered by follicular estrogen.
    • The peak of LH triggers ovulation.
    • In the secretory phase without fertilization, LH and FSH levels decline.
    • Progesterone is the primary hormone responsible for negative feedback during the secretory phase.

    Early Pregnancy and HCG

    • During pregnancy, progesterone suppresses the maternal hypothalamic-pituitary-ovarian axis.
    • The trophoblast begins secreting human chorionic gonadotropin (HCG) 8 days after ovulation.
    • HCG maintains the corpus luteum, preventing it from degenerating.

    Hormonal Sources in Pregnancy

    • In the second and third trimesters, the placenta becomes the main source of estrogen and progesterone.
    • Around 16-20 weeks of gestation, the corpus luteum resolves.
    • The uterine endometrium thickens and forms the decidua during pregnancy.

    Changes in Hormonal Levels

    • HCG levels peak around gestational week 9 before declining.
    • Cholesterol is converted to pregnenolone in the placenta during late pregnancy.
    • DHEA-sulfate is hydroxylated to 16-OH DHEA-sulfate in the fetal liver.
    • Estriol is produced by the placenta from 16-OH DHEA-sulfate.

    Transition in Hormonal Production

    • Progesterone production shifts from the corpus luteum to the placenta during the second trimester.
    • The corpus luteum forms following ovulation induced by the LH surge.
    • If fertilization does not occur, the uterine endometrium undergoes necrosis and is eliminated.

    Role of the Corpus Luteum

    • The corpus luteum forms during the secretory phase and produces large amounts of progesterone and some estrogen.
    • Estrogen levels decline during the secretory phase without fertilization.
    • After the degeneration of the corpus luteum, the corpus albicans forms.

    Follicle Maturation and the Placenta

    • LH from the corpus luteum increases progesterone levels.
    • LH and FSH remain low during the menses phase.
    • Estrogen during the proliferative phase induces rapid proliferation of the uterine endometrium.
    • If fertilization occurs, progesterone levels steadily increase.
    • The placenta formation occurs during the secretory pregnancy phase.
    • During the second trimester, the placenta assumes the role of steroid hormone production, suppressing new follicle maturation.

    Late Pregnancy Functions

    • The placenta converts cholesterol to pregnenolone, crucial for hormone synthesis in late pregnancy.

    Menstrual Cycle Overview

    • LH and FSH levels are low during the menses phase.
    • The proliferative phase is triggered by increasing follicular estrogen, leading to elevated LH and FSH.
    • The peak of LH triggers ovulation, the release of the oocyte.
    • In the secretory phase without fertilization, LH and FSH levels decline.
    • Progesterone primarily maintains negative feedback during the secretory phase.

    Pregnancy Hormones

    • Progesterone suppresses the maternal hypothalamic-pituitary-ovarian axis during pregnancy.
    • The trophoblast secretes human chorionic gonadotropin (HCG) about 8 days post-ovulation.
    • HCG maintains the corpus luteum, which is crucial for early pregnancy.
    • The placenta takes over estrogen and progesterone production in the second and third trimesters.
    • The corpus luteum resolves around 16-20 weeks of gestation.

    Endometrial Changes During Pregnancy

    • The uterine endometrium thickens and transforms into the decidua during pregnancy.
    • HCG levels peak at around 9 weeks of gestation and then decline.
    • Cholesterol is converted to pregnenolone in the placenta during late pregnancy.
    • DHEA-sulfate is hydroxylated to 16-OH DHEA-sulfate in the fetal liver.

    Estriol Production

    • Estriol is produced by the placenta from 16-OH DHEA-sulfate.
    • Progesterone production shifts from the corpus luteum to the placenta in the second trimester.

    Follicular Development

    • The formation of the corpus luteum is stimulated by an LH surge post-ovulation.
    • If fertilization does not occur, the endometrium undergoes necrosis and is eliminated as menstruation.
    • The corpus luteum forms during the secretory phase and produces progesterone and estrogen.

    Hormonal Feedback Mechanisms

    • Estrogen levels decline during the secretory phase without fertilization.
    • After the corpus luteum degenerates, it becomes the corpus albicans.
    • Progesterone increases due to LH action from the corpus luteum.

    Lactation and Breast Function

    • Estrogen and progesterone stimulate breast development during pregnancy.
    • Prolactin is the main hormone responsible for milk production.
    • High levels of estrogen and progesterone during pregnancy inhibit prolactin's action.
    • Suckling triggers prolactin secretion for milk production; oxytocin is responsible for milk ejection.

    Labor and Delivery

    • Stretching of the cervix triggers the release of oxytocin during labor.
    • Oxytocin's feedback system is positive, enhancing uterine contractions.
    • Estrogen up-regulates oxytocin receptors and increases uterine contractility as gestation progresses.

    Final Notes on Pregnancy Physiology

    • Fetal cortisol production is activated near term, increasing uterine contractility.
    • The blastocyst contributes to the fetal portion of the placenta, crucial for nutrient exchange and hormone production.
    • The placenta acts as both a transport epithelium and an endocrine gland, vital for maintaining pregnancy.

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    Description

    This quiz explores the energy sources stored in skeletal muscle, including the roles of various proteins and molecules involved in muscle function. Test your knowledge on glycogen, ATP, myoglobin, and related concepts in muscle physiology.

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