Biology

• Reproductive System


  The system of organs that enables reproduction and the continuation of a species
• 5 words related to the reproductive system

  • Word 1
  • Word 2
  • Word 3
  • Word 4
  • Word 5
• Anne and Drew


  • 13 years old
  • Experiencing changes in their body
  • Grew taller
  • Increased growth of hair in armpit and pubic area
• Anne


  • Complained about pimples and acne production
  • Noticed chest area beginning to grow
  • Hips become more pronounced, rounded and curvy
• Drew


  • Noticed increased muscle growth
  • Wider shoulders
  • Narrower hips
  • Voice changed and became deeper
• Some group members experienced early signs of puberty as young as 10 years old, while others experienced it at a later age
• Changes Anne will experience

  • Menstruation
  • Skin changes
  • Mood swings
  • Pubic hair growth
• Changes Drew will experience

  • Testicles and penis increase in size
  • Pubic hair growth
• Puberty is primarily triggered by hormonal changes, with the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus, stimulating the production of sex hormones, such as estrogen and testosterone, leading to physical and reproductive maturation
• Genetic factors, environmental cues, and nutrition also play roles in influencing the onset and progression of puberty
• Endocrine Gland


  Organs of the Endocrine System that produce and secrete (release) Hormones
• Hormones


  Chemical messengers secreted (released) from glands into the blood that affect cells in another part of the body
• Target Cells


  Cells that have special receptors that "recognize" the hormones and allow them to influence that cell
• Functions of the Endocrine System

  • Regulates, coordinates, and controls growth and development
  • Male and female development
  • How your body uses energy
  • Levels of salts and sugars in your blood
  • The amount (volume) of fluid in your body
  • Appetite
  • Many other body functions
• Pituitary Hormones


  • Follicle-stimulating hormone
  • Luteinizing hormone
  • Growth hormone
  • Oxytocin
• Follicle-stimulating hormone


  Stimulates egg maturation in the ovary and release of sex hormones
• Luteinizing hormone


  Stimulates maturation of egg and of the corpus luteum surrounding the egg, which affects female sex hormones and the menstrual cycle
• Growth hormone


  Stimulates growth during infancy and puberty
• Oxytocin


  Affects childbirth, lactation, and some behaviors
• Endocrine Hormones


  • Testosterone (in testes)
  • Estrogen (in ovaries)
  • Progesterone (in ovaries)
  • Testosterone (in adrenal medulla)
• Testosterone


  Regulates sperm cell production and secondary sex characteristics
• Estrogen


  Stimulates egg maturation, controls secondary sex characteristics
• Progesterone


  Prepares the uterus to receive a fertilized egg
• Testosterone (in adrenal medulla) affects adult body form (greater muscle mass), libido
• Feedback mechanism


  Process through which the level of one substance influences the level of another substance
• Negative feedback


  • Affects the production of hormones in the menstrual cycle
  • High levels of one hormone may inhibit the production of another hormone
  • Reverses a change in controlled condition
• Positive feedback


  • The response strengthens the change in a controlled condition
• Negative feedback


  When enough hormone is in the body, the body stops producing the hormone until it is needed again
• Glucose regulation


  1. Glucose in blood increases

  2. Receptors notify brain

  3. Brain sends message to pancreas to produce insulin

  4. Insulin tells muscle and liver to take up glucose

  5. Blood glucose level drops

  6. Pancreas stops making insulin
• Diabetes is caused by the body not producing enough insulin or the target cells becoming resistant and unresponsive to it
• Childbirth


  1. Pituitary gland sends signal via oxytocin to uterus causing contractions

  2. Pressure of fetus on cervix sends signal back to brain

  3. Brain stimulates release of more oxytocin

  4. More contractions

  5. Cycle continues until birth
• When normal functions lose their negative feedback control, disease is often the result
• Thyroid regulation


  1. Hypothalamus secretes TRH

  2. TRH stimulates pituitary to secrete TSH

  3. TSH stimulates thyroid to produce hormones

  4. High thyroid hormone levels inhibit TRH secretion

  5. Disruption of this process leads to hyperthyroid disease
• Sequence of events in menstrual cycle

  • Pituitary gland controls and starts cycle
  • Pituitary releases hormones to mature egg
  • Ovary releases estrogen to thicken uterine lining
  • Ovary releases egg
  • Unfertilized egg not implanted, uterine lining shed (menstruation)
  • Cycle starts again
• Follicle stimulating hormone (FSH)


  Stimulates ovaries to release estrogen, high estrogen prevents further FSH production
• Estrogen


  Stimulates release of luteinizing hormone (LH), high progesterone inhibits further LH release
• Events following fertilization
• Short quiz: Google form
• DNA is the genetic material within the nucleus
• Replication


  Creates new copies of DNA