BIO 1150 1st Edition Lecture 13Topic Discussed: Reproduction and Nervous SystemOvaries- site of egg maturation in follicles• Ovum maturation starts and doesn’t finish before birth. • Females are born with several hundred thousand eggs• Most ova are reabsorbed, few ovulateEach cycle after puberty one egg and follicle further develop to ovulation• If ova isn’t fertilized it doesn’t undergo meiosis IIEgg is housed in a follicle (primary)• Secretes fluid (in the follicle), then the egg inside is mature• Ovulation- egg released from follicleOvum/ follicle development with hormones• GnRH (gonadotropin releasing hormone) hypothalamus, stimulates LH/ FSH release• LH (luteinizing hormone) anterior pituitary, stimulates ovulation• Estrogen- stimulates uterine development• Progesterone (corpus tuteum) stimulates uterine maturation• LH and FSH levels cycle with changes in follicle• Levels increase during ovulation• LH surge- trigger for ovulationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.• Estrogen- secreted by follicle• Negative feedback= increase in estrogen and decrease in LH• Positive feedback= increase in estrogen and increase in LHBirth control- estrogen kept at a constant high which inhibits the LH surgeLuteinizing hormone- yellow- corpus lleudiumDecrease in progesterone/estrogen- triggers lining of uterus to shed (menstruation)Menopause= high LH, low estrogenCycle Length• Menstrual phase- few days• Follicular phase- varies in length • Luteal phase- 2 weeks long• Menstruation occurs 2 weeks after ovulationFertility• Egg lives for about 24 hours after ovulation • Sperm can live in women for 72 hours• Woman is ferile 3 days before and 1 day after ovulation• Low temperature- fertile• High temperature- infertileFertilization occurs in oviduct Nervous System• Central Nervous Systemo Brain/spinal cordo Receives, stores and transfers info• Peripheral Nervous Systemo Nerves that lie outside CNSo Cranial nerves= brain/spinal nerves = spinal cordNervous system cells• Neurons- generate electrical activity (action potentials) to communicate quickly between areas of the body• Glial cells- protect and support neurons in CNS/ PNSNeuron Types• Sensory- respond to stimuli and transmit info to CNS• Interneurons- transmit info within the CNSMotor- transmit action potentials from CNS to peripheral tissues• Soma- cell body • Dendrites- info towards somao Info awayo Attaches to different cellGlial cell (neuroglia)- supportive cell, they don’t conduct electricity• Astrocytes- provide barrier between blood vessels and brain cells• Schwann- produces myelinNeurons form complex networksElectrical signaling- fundamental mechanism of nervous system, used for communication• Hodgkins and Huxley- nerve cells with squid• Axom (of squid) = 1mm diameterKey to electricity in cells = ions• Sodium and potassium pump- removes sodium ions from cell and gains potassium ions• Negative charge inside relative to outside• Ions not in equilibrium• Ions move down concentration gradient• Carry change• Then electrical potential difference (voltage) formsVoltage gated ion channels- electrical environment influences the shape and function of the protein channelAction Potential (AP)- transient change in membrane voltage (Vm)• Short lived• Caused by changing membrane permeability to ions• Sodium comes in, shifts voltage to
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