Review Questions for Chapter 4 1 What is circumcision the surgical removal of the foreskin or prepuce 2 What are the corpora cavernosa Main erectile part of the penis It fills with blood and becomes hard 3 What is the corpus spongiosum Mass of spongy tissue that surrounds the urethra Allows the urethra to remain open during erection 4 What are the seminiferous tubules What is their function the site of spermatogenesis and dominate the structure of the testes 5 What is the epididymis a C shaped structure located behind each testis through which sperm travel and mature 6 What are the functions of the Sertoli cells the Leydig cells Sertoli cells nourish developing sperm as they undergo 1st 2nd meiotic divisions and also remove much of their cytoplasm Leydig cells produce testosterone 7 What is the location and function of the prostate gland It surrounds the urethra just below the urinary bladder It produces 30 of the contents of sperm 8 What is the main contribution of the seminal vesicle They produce 70 of semen 9 What keeps the penis flaccid when a male is not sexually aroused Sympathetic or parasympathetic nervous system What does it do Sympathetic via norepinephrine actively inhibits erection in the normal state It constricts arterioles 10 How is an erection produced Nitric oxide NO from parasympathetic nerves vasodilates arterioles relaxes smooth muscle in corpora cavernosa So much blood flows into the corpora cavernosa that it presses against the venous outflow and traps blood there 11 What is the role of nitric oxide NO 12 How do Viagra Cialis Levitra work Vasodilates arterioles and relaxes smooth muscles in the corpora cavernosa They prolong the effect of nitric oxide by inhibiting the enzyme that breaks down cGMP NO s second messenger 13 How is ejaculation produced The urethra and muscles of the pelvic floor contract ejecting semen through the urethral meatus 14 Why do the testicles hang down outside of the abdomen To regulate temperature Production or storage of sperm requires temperature 4 7 degrees C lower than body temp 15 What are spermatogonia and where are they located an undifferentiated male germ cell originating in a seminiferous tubule and dividing into two primary spermatocytes 16 Where do the first and second meiotic divisions occur in sperm production Seminiferous tubules 17 What happens in the epididymis Sperm become capable of moving and also more concentrated 18 What are 3 major components of semen Seminal fluid prostate fluid and cowpers fluid 19 What is the vomeronasal organ What does it do An auxiliary olfactory sense organ it is used to detect pheromones 20 What is the main integrative area for control of male sexual behavior What transmitter is released there before and during mating The MPOA Dopamine each 21 What are three brain areas where dopamine is released during mating What is the role of Nigrostriatal tract initiation of movement Mesolimbic tract general motivation MPOA male sexual behavior 22 How good is the correlation between testosterone levels and sexual ability in humans What factors may be more important than testosterone levels for explaining individual differences in males sex drive Correlation is not very high Differences in target tissues hormone receptors transmitters may be more important Review Questions for Chapter 5 1 What is the order of production of the 4 major gonadal steroids Progesterone Testosterone Estradiol DHT 2 Why is testosterone sometimes called a prohormone because it can be converted to either DHT or Estradiol 3 What is the main way in which steroids act How is this different from the actions of peptide hormones Steroid hormones are non polar and can cross cell membranes to reach intracellular receptors which they then bind to Peptide hormones are water soluble polar can t cross cell membranes and attach to cell surface receptors 4 What is oxytocin and where is it secreted Where are the cell bodies that make it Oxytocin is a hormone that causes contractions of smooth muscles during orgasm childbirth and breast feeding It is secreted into the bloodstream from the posterior pituitary It is made by cell bodies in the hypothalamus 5 How does the anterior pituitary differ from the posterior pituitary Anterior pituitary is made of glandual tissue and releases FSH and LH and the posterior pituitary is made of neural tissue and it releases oxytocin and vasopressin 6 Describe Bertoldt s experiment with roosters Why were his conclusions radical at the time He castrated young roosters and observed that they did not exhibit normal sex behavior and development He made a radical discovery that a blood borne product being produced by the testes were present There was non neural control of behavior 7 How can one hormone have numerous different effects on the body Different cells can have receptors for the same hormones but binding of the hormone to a specific cell can have a different effect depending on what type of cell it is One messenger multiple messages 8 What are some effects of anabolic androgens other than muscle growth Sterility liver disease unhealthy blood lipids roid rage hair growth in women and voice changes acne 9 What is GnRH where is it secreted and what does it do stimulates the release of gonadotropin FSH LH 10 What is FSH where is it secreted and what does it do Gonadotropin releasing hormone it is secreted by the hypothalamus and it Follicle stimulating hormone it is secreted by the anterior pituitary and enters Sertoli cells and leads to sperm maturation in males and enters granulosa cells in women to produce E and to grow oocyte 11 What is LH where is it secreted and what does it do 3 functions Lutenizing hormone secreted by the anterior pituitary It enters Leydig cells to produce testosterone it enters thecal cells in femals to also produce testosterone and LH breaks the gap junctions between oocyte granulosa cells that prevented 1st meiotic division 12 What are two major functions of granulosa cells early in the follicular phase They produce estrogen and grow the oocyte 13 How are male and female types of endocrine control similar and how are they different Only difference in the pattern of endocrine control between males and females is the positive feedback response to estrogen by females resulting in outpouring of LH and FSH when estrogen levels are high enough Some men may respond to injection of E with a smaller later LH surge but they don t have high E in normal conditions 14 What are 2 major