Midterm Chapter 26 Flashcards
What are autosomes?
Chromosomes other than sex chromosomes.
Female chromosomes.
XX
Male chromosomes.
XY
Sex chromosomes/sperm or ova/germ cells
X or Y
inactivated X chromosome.
Barr body
Fertilized egg.
XX or XY
The Y chromosome contains a region for male sex determination that is know as what gene?
SRY gene
List the functions of the gonads. How do the products of gonadal function differ in males and females?
Gonads produce gametes and secrete sex hormones
Female gametes - egg (ovaum) secrete estrogen, progesterone, androgens, and inhibin
Male gametes - sperm secretes androgen and inhibin
What are inhibins?
hormones that inhibit FSH secretion.
What are activins?
peptide hormones that stimulate FSH secretion
Define aromatase.
An enzyme in the testes and ovaries that convert androgens to estrogens.
Define blood-testis barrier.
tight junctions that prevent free movement of substances between blood and seminiferous tubule lumen.
Define Androgen-binding protein
Sertoli cell protein secreted into seminiferous tubule lumen, where it binds and concentrates androgens.
Define first polar body
formed by the first meiotic division of primary oocyte; disintergrates and has no function
Define acrosome
lysosome-like structure in the head of sperm; contains enzymes essential for fertilization.
Trace the anatomical routes to the external environment followed by a newly formed sperm and by an ovulated egg. name all structures the gametes pass through on their journey.
Newly formed sperm: seminiferous tubule -> epididymis -> ductus (vas) deferens -> ejaculatory duct (passing the seminal vesicles, prostate gland, and bulbourethral glands) -> urethra.
Ovulated egg: fallopian tube -> uterine cavity -> cervix -> vagina
All testosterone is produced in the testes. T/F
False - some are produced in the adrenal glands of both sexes
Only males make androgens and only females make estrogens. T/F
False - both sexes produce both hormones
Anabolic steroid use appears to be addictive, and withdrawal symptoms include psychological disturbances. T/F
True
High levels of estrogen in the late follicular phase help prepare the uterus for menstruation. T/F
False - high levels of late follicular estrogen help prepare the uterus for implantation of fertilized ovum.
Progesterone is the dominant hormone of the luteal phase of the ovarian cycle. T/F
True
What is semen? What are its main components, and where are they produced?
A sperm-fluid mixture made mostly by the accessory glands Components and source: Sperm - seminiferous tubules Mucus - Bulbourethral glands Water - all accessory glands Buffers - prostate, bulbourethral glands Nutrients - seminal vesicles, prostate, epididymis enzymes - seminal vesicles and prostate zinc - unknown Prostaglandins - seminal vesicles
Why are X-linked traits exhibited more frequently by males than females?
Males have a Y chromosome, which often does not have a gene to match one found on the X chromosome. Thus, a male may inherit a recessive X trait and will exhibit it, while a female who inherits the same recessive trait will not exhibit it if her second X chromosome has the dominant gene for the trait.
What does GnRH stand for?
Gonadotropin Releasing hormone
