Psl300 Test 3| 216 Questions| With Complete Solutions
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Psl300
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Psl300
Which gametes are responsible for sex? correct answer: The sex chromosomes (X or Y)
Bipotential Primordium correct answer: Has both mullerian duct and wolffian duct, potential for either male or female development.
XX Structure development correct answer: Mullerian duct persists and forms ...
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Psl300 Test 3| 216 Questions| With
Complete Solutions
Which gametes are responsible for sex? correct answer: The sex
chromosomes (X or Y)
Bipotential Primordium correct answer: Has both mullerian
duct and wolffian duct, potential for either male or female
development.
XX Structure development correct answer: Mullerian duct
persists and forms the fallopian tube, uterus, and upper third of
the vagina, including the cervix. Wolffian duct regresses due to
lack of testosterone. Gondal cortex forms ovary, gondal medulla
regresses.
XY extra gene correct answer: Y chromosome has SRY gene
that promotes testes development. This encodes a TDF (testes
development factor). SRY is a gene regulatory protein.
SF1: Steroidogenic factor 1 (transcription factor)
SRY: Testes form (doesn't need testosterone)
AMH: anti-mullerian hormone
Development of sertoli cells = AMH & testes
Development of leydig cells = testosterone
SOX9 in gonadal development correct answer: - Both males
and females start with low levels of SOX9.
- In females, no SRY drops level of SOX9 and beta catenin
further represses SOX9.
,- In males, SRY increases amount of SOX9 and has pro-male
structures while repressing beta catenin.
What does SOX9 do? correct answer: It initiates sertoli cell
differentiation. Once cells are differentiated, it allows for further
development and structure's formation.
XY Structure development correct answer: SRY directs medulla
to form into testis, AMH causes Mullerian duct to disappear.
Testosterone converts wolffian ducts to seminal vesicle, vas
deferens, and epididymis. DHT controls prostate development.
Gondal cortex regresses.
Hormones in structural development XY correct answer: After
SRY gene, testes start to form, leydig cells secrete testosterone
(which turns into DHT for prostate + external), and sertoli cells
secrete AMH.
Hormones in structural development XX correct answer: Beta
catenin suppresses SOX9, no AMH or testosterone.
XY with atypical androgen synthase (eg 5 alpha reductase)
correct answer: Testosterone can't be converted into DHT,
structures needing DHT are affected.
XX excessive exposure to androgens correct answer: Maybe
results in some internal male characteristics that are due to
testosterone.
,At the onset of puberty, what is activated? correct answer:
GNRH system is activated, which releases signals from the
hypothalamus into the anterior pituitary. This releases FSH and
LH at a much higher frequency. XY individuals usually undergo
puberty at a later time than XX individuals.
What does LH and FSH do in puberty? correct answer:
Stimulates the gonads to start pumping out their respective
hormones to stimulate secondary sex characteristics. This starts
the feedback loop involved in this system.
Peripheral nervous system correct answer: All neurons and
parts outside the CNS, includes somatic (controlled) and
autonomic nervous systems (uncontrolled actions, enteric
system)
Central nervous system correct answer: Neurons in the brain
and spinal cord
How many neurons in the brain and spinal cord? correct answer:
86B and 1B
Enteric system # of neurons correct answer: 100-600 million,
about same for peripheral
How many glial cells do we have? correct answer: Around the
same number as we have of neurons.
, Ventricals correct answer: Filled with cerebrospinal fluid.
Includes lateral ventricle, third ventricle, fourth ventricle, and
central canal of spinal cords. All are continuous.
Grey matter (CNS) correct answer: Nerve cell bodies,
unmyelinated axons. Cell bodies are arranged in clusters, or
nuclei of cell bodies
White matter (CNS) correct answer: Myelinated axons running
in bundles called tracts.
White matter (PNS) correct answer: Nerves
Grey matter (PNS) correct answer: Ganglia
How much energy does the CNS use? correct answer: Even
though brain is 2% of mass, gets 15% of blood and 50% of
glucose. Needs as much energy as a lightbulb (40 watts). Brains
are ahead of computers in terms of energy ratio.
How is CNS energy efficient? correct answer: Neurons spike
around once every 6 seconds, so only 4% of your neurons are
firing at once. Communication is expensive, and the brain is a
stingy hoe.
Segments in the spinal cord correct answer: There are 31
segments, with a pair of nerves coming from each.
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