Human Physiology Quiz
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Questions and Answers

What stimulates the conversion of 25-hydroxyvitamin D to its active form?

  • Parathyroid Hormone (PTH) (correct)
  • Insulin
  • Calcitonin
  • Melatonin

    • Which organ plays a key role in the reabsorption of calcium?

  • Pancreas
  • Intestines
  • Kidneys (correct)
  • Liver

    • How does calcitonin impact blood calcium levels?

  • Has no effect on blood calcium levels
  • Decreases calcium by inhibiting renal excretion
  • Reduces calcium by promoting bone deposition (correct)
  • Increases calcium by promoting bone resorption

    • What defines the master clock in the human body?

    <p>Suprachiasmatic Nucleus (SCN)</p> Signup and view all the answers

    What does the term 'zeitgeber' refer to in circadian rhythm regulation?

    <p>An environmental cue that synchronizes biological clocks</p> Signup and view all the answers

    Which structure carries light signals from the retina to the master clock?

    <p>Retinohypothalamic Tract (RHT)</p> Signup and view all the answers

    Which of the following is a physiological consequence of circadian rhythm disruption?

    <p>Increased risk of metabolic disorders</p> Signup and view all the answers

    What type of light is particularly effective in resetting the circadian clock?

    <p>Blue Light</p> Signup and view all the answers

    What is the primary function of the GnRH released by the hypothalamus?

    <p>To regulate the secretion of FSH and LH from the anterior pituitary.</p> Signup and view all the answers

    During which phase does positive feedback occur in the female reproductive cycle?

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

    What characterizes continuous production in males compared to females?

    <p>Constant production of testosterone and sperm.</p> Signup and view all the answers

    What primarily determines biological sex during embryonic development?

    <p>The presence of the SRY gene and hormonal signaling.</p> Signup and view all the answers

    What is a characteristic of the process of oogenesis?

    <p>Oogonia divide mitotically during fetal development.</p> Signup and view all the answers

    How does androgen insensitivity syndrome (AIS) affect individuals with XY chromosomes?

    <p>They produce testosterone but cannot respond to it effectively.</p> Signup and view all the answers

    What role does FSH play in male reproduction?

    <p>It supports spermatogenesis by stimulating Sertoli cells.</p> Signup and view all the answers

    Which aspect of gender is distinct from biological sex?

    <p>Psychological and social identity</p> Signup and view all the answers

    What is the primary role of calcitonin in calcium homeostasis?

    <p>Lowers blood calcium levels</p> Signup and view all the answers

    Where is the majority of the body's calcium stored?

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

    Which of the following actions is directly stimulated by parathyroid hormone (PTH)?

    <p>Stimulated osteoclast activity</p> Signup and view all the answers

    Which of these cells are responsible for the absorption of dietary calcium and phosphate in the small intestine?

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

    What is the effect of rising blood calcium levels on PTH secretion?

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

    Which vitamin is synthesized in response to UV light exposure?

    <p>Vitamin D3</p> Signup and view all the answers

    What effect does PTH have on the kidneys regarding calcium handling?

    <p>Enhances calcium reabsorption</p> Signup and view all the answers

    Which of the following is NOT a role of osteoclasts?

    <p>Stimulating osteoblasts</p> Signup and view all the answers

    What is the role of progesterone during the secretory phase of the menstrual cycle?

    <p>Maintains the endometrium for implantation</p> Signup and view all the answers

    What is the first stage of parturition?

    <p>Cervical dilation</p> Signup and view all the answers

    Which hormone contributes to the amplification of uterine contractions during childbirth?

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

    What is the function of prolactin in lactation?

    <p>Stimulates milk production in alveolar cells</p> Signup and view all the answers

    What hormonal change occurs during menopause?

    <p>Decrease in estrogen and progesterone</p> Signup and view all the answers

    How does suckling affect ovulation during lactation?

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

    What is the significance of the post-reproductive lifespan in evolutionary terms?

    <p>Enables greater investment in offspring and grandchildren</p> Signup and view all the answers

    Which hormone is primarily responsible for initiating labor?

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

    What is the arrangement of pancreatic islets in teleosts compared to mammals?

    <p>Teleosts' islets are termed Brockmann bodies.</p> Signup and view all the answers

    What is a key difference in the ratio of A-cells and B-cells in the pancreatic islets of teleosts compared to mammals?

    <p>A-cells are more prominent in teleosts due to high-protein diets.</p> Signup and view all the answers

    Which hormone plays a less significant role in carbohydrate metabolism in teleosts compared to mammals?

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

    What can high phosphate levels do to calcium availability in the body?

    <p>Reduce calcium availability by binding calcium.</p> Signup and view all the answers

    What are the primary functions of the circadian clock?

    <p>Orchestrates circadian rhythms by regulating hormone release.</p> Signup and view all the answers

    Which of the following hormones is primarily responsible for increasing blood calcium levels?

    <p>Parathyroid Hormone</p> Signup and view all the answers

    How do core clock genes interact within the circadian clock mechanism?

    <p>CLOCK and BMAL1 form a positive feedback loop while PER and CRY provide negative feedback.</p> Signup and view all the answers

    What is the role of light in circadian regulation for monarch butterflies?

    <p>Light resets their internal clock daily.</p> Signup and view all the answers

    What is the primary function of Vitamin D in relation to calcium and phosphate?

    <p>Promotes absorption of calcium and phosphate in the gut.</p> Signup and view all the answers

    What impact has climate change had on bird migration patterns?

    <p>It has shifted migration timing by causing birds to spend more time in northern areas.</p> Signup and view all the answers

    How does the exocrine function of the pancreas in teleosts compare to that of mammals?

    <p>Both secrete the same types of digestive enzymes.</p> Signup and view all the answers

    What role does glucagon play in teleosts compared to mammals?

    <p>Glucagon is critical for gluconeogenesis in teleosts.</p> Signup and view all the answers

    Which of the following statements correctly describes the function of the endocannabinoid system (ECS)?

    <p>ECS consists of endogenous ligands that resemble THC and CBD.</p> Signup and view all the answers

    Which of the following genes are considered key in the migratory navigation of monarch butterflies?

    <p>PER, CRY, and TIM (Timeless).</p> Signup and view all the answers

    What physiological effect does disruption of environmental cues have on birds?

    <p>It causes mistimed breeding, impacting population dynamics.</p> Signup and view all the answers

    Which molecules are involved in the positive feedback loop of the molecular clock?

    <p>CLOCK and BMAL1 activate the expression of downstream output genes.</p> Signup and view all the answers

    Study Notes

    Mammalian Reproduction

    • The Hypothalamic-Pituitary-Gonadal (HPG) Axis controls pituitary function.
    • Hypothalamus releases GnRH, controlling pituitary function.
    • Anterior Pituitary releases FSH and LH in response to GnRH.
    • Gonads produce hormones:
      • Males: Testes produce testosterone (androgens).
      • Females: Ovaries produce estrogen and progesterone.
    • Hormonal Feedback:
      • Negative feedback regulates GnRH, FSH, and LH levels in males and females.
      • Positive feedback in females during ovulation: High estrogen stimulates an LH surge, causing ovulation.
    • Differences in Males and Females:
      • Males: Continuous sperm and testosterone production.
      • Females: Cyclic ovarian activity (estrous or menstrual cycles).

    Sex vs. Gender

    • Biological Sex is defined by physical traits:
      • Chromosomal sex (XX or XY).
      • Gonadal sex (testes or ovaries).
      • Phenotypic sex (external genitalia, secondary sex characteristics).
    • Sex determined during embryonic development, by the SRY gene and hormonal signaling.
    • Gender is psychological and social identity, not necessarily aligned with biological sex and influenced by societal norms.
    • Intersex variations occur when chromosomal, gonadal, or phenotypic sex do not align.
      • Examples: Androgen Insensitivity Syndrome (AIS), Congenital Adrenal Hyperplasia (CAH).

    Gametogenesis

    • Spermatogenesis:
      • Location: Seminiferous tubules in the testes.
      • Process: Spermatogonia (diploid stem cells) divide mitotically, primary spermatocytes undergo meiosis I, secondary spermatocytes undergo meiosis II, spermatids mature into spermatozoa.
    • Oogenesis:
      • Location: Ovarian follicles.
      • Process: Oogonia divide mitotically during fetal development. Primary oocytes are arrested in prophase I until puberty. During ovulation, meiosis I completes, forming a secondary oocyte (arrested in metaphase II) and a polar body. Meiosis II only completes with fertilization. FSH stimulates follicular growth, and LH triggers ovulation and corpus luteum formation.

    Sexual Differentiation

    • SRY gene on the Y chromosome encodes Testis-Determining Factor (TDF), which induces Sertoli and Leydig cell differentiation in males.
    • Sertoli cells secrete anti-Müllerian hormone (AMH) causing regression of Müllerian ducts.
    • Leydig cells produce testosterone, promoting Wolffian duct differentiation.
    • In the absence of the SRY gene, gonadal ridge differentiates into ovaries.
    • Müllerian ducts persist and develop into the uterus, fallopian tubes, and upper vagina
    • Lack of testosterone causes regression of Wolffian ducts.

    Reproductive Cycles

    • Estrous Cycle (Non-Primate Mammals): Proestrus, Estrus, Metestrus, Diestrus.
    • Menstrual Cycle (Primates): Follicular and Luteal phases regulated by estrogen and progesterone.
    • Seasonal Breeders: Cycles controlled by photoperiod.

    Hormonal Regulation of Reproduction

    • FSH and LH stimulate follicular development and ovulation in females.
    • Estrogen promotes endometrial regrowth.
    • Progesterone maintains the endometrium during the secretory phase, supporting pregnancy.
    • Hormones influence the timing of reproductive cycles, like timing of breeding seasons and ovulation

    Parturition (Childbirth)

    • Stages: Cervical dilation (uterine contractions), Delivery of Fetus (coordinated uterine and abdominal contractions), Delivery of the Placenta (placenta detaches).
    • Hormonal control: Estrogen increases uterine sensitivity to oxytocin, prostaglandins amplify contractions, fetal cortisol enhances placental estrogen production.

    Lactation

    • Pre-pregnancy: Estrogen promotes ductal growth, progesterone influences lobular-alveolar development.
    • Prolactin prepares mammary glands for milk synthesis.
    • After parturition: Progesterone and estrogen levels fall, enabling prolactin stimulated milk production.
    • Oxytocin promotes milk ejection by contracting myoepithelial cells.
    • Lactational amenorrhea: Suckling suppresses GnRH, reducing FSH and LH secretion.

    Menopause

    • Definition: Permanent cessation of menstrual cycles due to ovarian follicle depletion.
    • Hormonal changes: Declining estrogen and progesterone, increased FSH and LH.

    Other topics

    • Feeding and Metabolism: Various non-mammalian feeding strategies (herbivores, carnivores, etc.), adaptations in digestive systems like stomach-less teleosts and pyloric caecae. Non-mammals often rely more on protein catabolism for energy.
    • Calcium and Phosphate Homeostasis: Bone health, hormonal regulation of calcium and phosphate (PTH, vitamin D, calcitonin), key cells (osteoblasts, osteoclasts, osteocytes), kidney and intestinal involvement.
    • Diabetes: Blood sugar control, type 1 and 2 diabetes, endocrine complications, impact on metabolism, glucosuria.
    • Stress Response: Hypothalamic-Pituitary-Adrenal (HPA) axis, acute and chronic stress, effects of stress on hormone regulation.
    • Endocrine System: Role of endocrine hormones like ghrelin, leptin, insulin, CCK, PYY, and various other hormones.
    • Opioids: Endogenous Opioid system, role in stress response and pain modulation.
    • Endocannabinoid System: ECS ligand modulation, stress, and seasonal hormonal cycles.
    • Clock Regulation: Circadian rhythms, SCN, light signaling, environmental factors impacting synchronization. This includes reproductive cycles affected by light and temperature.
    • Types of Reproduction and Key Differences: Monotremes (oviparous), Marsupials (short gestation), Eutherians (placental).
    • Nonmammalian Reproductive Biology: Focusing on specifics from the readings, including examples for the various reproduction types, like amphibians, reptiles, birds, fish, etc., covering reproduction methods (internal vs external, how they reproduce, eggs, etc.). Key difference discussion between tropical and temperate crocodilians (including seasonal reproduction cycles, temperature variation, and egg incubation).

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    Description

    Test your knowledge on human physiology concepts, including vitamin D metabolism, calcium reabsorption, circadian rhythms, and reproductive biology. This quiz covers essential functions and disruptions related to various physiological processes in the human body.

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