unit 6 pt 2 Flashcards
(82 cards)
asexual vs sexual reproduction
asexual: 1 parent, identical offspring, meiosis doesn’t happen, mitosis happens, only get variation from mutations
sexual: 2 parents, non identical offspring,meiosis happens, mitosis happens, genetic variation from crossing over and random orientation, more likely to go through natural selection
asexual organisms
prokaryotes, plants, bacteria
meiosis advantage
increases variation
asexual advantage
being able to reproduce quickly and creat exact copy that’s already adapted to environment
what is male and female based off in humans
gametes
male vs female gametes
male: travels toward female, smaller, only holds nutrients for energy to move, more of them
female: doesn’t move, bigger, holds lots of nutrients, less of them
how are gametes produced
produced by meiosis, combined by fertilization, make genetic variation
male reproductive system
-2 testis sperm-also produce testosterone
-scrotum holds testis outside body
-epidymus stores sperm
-sperm travels through sperm duct when ejaculated
-seminal vesicle and prostate gland produce semen to increase sperm’s speed
-sperm goes out uretha
-penis is for penetrating female reproductive system
female reproductive system
egg is produced in 2 ovaries
egg travels down oviduct-site of fertilization
egg reaches uterus-stays if fertilized
egg passes through cervix
egg passes through vagina
vagina is protected by vulva on the outside
menstrual cycle order
menstruation, follicular phase, ovulation , luteal phase
follicular phase
FSH produced by pituitary gland
follicle produces estrogen causing follicle to have more FSH receptors-positive feedback
ovulation
when estrogen peaks in follicular phase, LH is produced by pituitary gland
causes release of egg from LH peak
LH peak causes estrogen to go back down
luteal phase
LH at peak turns follicle into corpus luteum
corpus luteum makes progesterone which builds lining of uterus with the help of some estrogen
LH and FSH go back down
if there’s no embryo, egg passes out body
progesterone and estrogen go back down and uterus lining sheds since its not needed-menstruation
FSH produced-cycle restarts
fertilization in humans
-egg releases hormones that tell sperm where it is
-when sperm reaches egg, it releases enzymes to dissolve outer layer of the egg
-sperm releases nucleus into egg
-rest of sperm dissolves including mitochondria
-after sperm dissolves, the outside of egg hardens to keep other sperm out
-for awhile, nuclei stay separate until mitosis I when nuclei dissolve in prophase
in vitro fertilization steps
-get control of mothers menstrual cycle by giving her drugs to decrease almost all of the 4 hormones
-high amounts of FSH and LH are injected
-many eggs released
-eggs then removed and place in petri dish and mixed with fathers sperm
-eggs can be put back in mothers uterus or put in surrogate
-wall must be built up by estrogen and progesterone
possibilities of vitro fertilization
high chance of problems or twins
surrogates immune system can attack new cells
blood glucose
moves around for cell repsiration
controlled by pancreas
what are islets of Langerhans
cells that regulate blood sugar
alpha cells
islets that make hormones when glucose is too low
-produce glucagon which breaks down glycogen which releases glucose into blood
beta cells
islets that produce hormones(insulin) when glucose is too high
-insulin stimulates cells that absorb glucose causing it to go down
diabetes type 1
comes from DNA mutation in gene for insulin-glucose is too high
-treated by being given insulin
diabetes type 2
develops over time usually from poor health
-insulin produced too much so now insulin receptors break down
- much harder to treat
thermoreceptors
monitor body temp
skin cells have many to monitor temp outside body
chemical regulation of body temp
-thermoreceptors send signals to the hypothalamus in brain
-TRH is released in response to low temperature and targets pituitary gland
-pituitary gland sends out TSH which targets thyroid gland in neck
-thyroid gland releases thyroxin which releases all cells which make heat as by product of the increased cell respiration