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Physiology (MPP 3202) > Ch. 20 Day 2 > Flashcards

Ch. 20 Day 2 Flashcards

1
Q

Procreation

A

Sexual response varies between genders and individuals

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2
Q

Procreation: excitation

A

increased muscle tone, vasocongestion of sexual organs; aka arousal

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3
Q

Procreation: plateau

A

continued vasocongestion

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4
Q

Procreation: orgasm

A

contraction of uterus/vagina and male ejaculatory organs

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5
Q

Procreation: resolution

A

body returns to pre-excitation condition

  • -men experience refractory period: not able to ejaculate
  • -females don’t really have refractory period
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6
Q

T/F: Stimulation or inhibition of erection can occur with or without input from higher brain centers.

A

True

-whole process of stimulation starts w/ nitric oxide

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7
Q

Parasympathetic stimulates or inhibits?

A

Stimulates

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8
Q

Sympathetic stimulates or inhibits?

A

Inhibits

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9
Q

Mechanism of penile vasodilatory response and basis for action of Sildenafil, similar vasoactive drugs work by inhibiting ____.

A

Phosphodiesterase (PDE-5)

PDE-5 activates Ca2+ channels, stimulates smooth muscle contraction –> vasoconstriction –> no erection

PDE-5 blocks Ca2+ entry, promotes smooth muscle relaxation –> vasodilation –> erection

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10
Q

Are there any comparable drugs currently marketed for female sexual dysfunction?

A

No

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11
Q

Male contraception

A

Vasectomy

  • a) most widely used and reliable form of male contraception
  • b) vas deferens cut and tied to prohibit sperm transport
  • c) does NOT affect testosterone production or ejaculation

Newer methods of contraception:

  • a) suppressing gonadotropin secretion
  • b) gossypol - interferes w/ sperm production
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12
Q

Female contraception

A

Contraceptive pill

  • a) includes synthetic estradiol and progesterone
  • b) acts like prolonged luteal phase
  • c) promotes negative feedback inhibition of GnRH –> no ovulation
  • d) endometrium still proliferates
  • e) placebo pills taken for 1 week to allow menstruation
  • f) newer pills have reduced risk for endometrial and ovarian cancers and reduction of osteoporosis
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13
Q

The most effective types of female contraceptives are those that?

A

Require the least effort by the user

–ex: implant, vasectomy, female sterilization

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14
Q

After ovulation, how long are the egg & sperm viable?

A

Egg is viable for about 1-2 days

Sperm survive 5-6 days in female reproductive tract

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15
Q

After fertilization, describe: Day 1, Days 2-4, Days 4-5, Days 5-9

A

Day 1: fertilization

Days 2-4: cell division

Days 4-5: blastocyst reaches uterus

Days 5-9: blastocyst implants in uterine wall

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16
Q

In order to become mfertilization-conpetant, sperm must undergo ____ in the female reproductive tract.

A

Capacitation

–enzymes on head of sperm are removed, sperm is now ready to fertilize egg

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17
Q

Sperm and fertilization

A

Over 300 million sperm enter female at ejaculation

  • only about 100 of these live to enter fallopian tube
  • in order to fertilize ovum, sperm must become capacitated; takes at least 7 hours after ejaculation
  • -> pH increases
  • -> hyperactivation of flagellum
  • capacitated sperm guided to oocyte by chemotaxis and thermotaxis
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18
Q

Fertilization occurs in?

A

Distal part of fallopian tube

sperm penetrates outer layers via enzymatically-mediated acrosomal reaction

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19
Q

Cortical reaction

A

when sperm enters oocyte, Ca2+ is released from endoplasmic reticulum

  • calcium wave travels through oocyte to opposite side from entry of sperm
  • Ca2+ has several effects:
  • -> prevents other sperm from entering oocyte (polyspermy)
  • -> activates oocyte to finish meiosis to become haploid ovum
20
Q

Fertilization

A

12 hours after sperm enter oocyte, nuclear envelope around ovum disappears, and chromosomes join to form a diploid zygote

  • -a) monozygotic (identical) twins - single ovum splits
  • -b) dizygotic (fraternal) twins - 2 eggs fertilized by sperm

Sperm contributes 1/2 chromosomes, centrosome

Egg contributes 1/2 chromosomes, cytoplasm, all other organelles

21
Q

Are mitochondria maternally or paternally inherited?

A

Maternally

22
Q

Why are mitochondria maternally inherited?

A

Autophagy is cellular process whereby worn-out/damaged proteins and organelles are degraded and their components recycled

There’s a type of autophagy that is mitochondrial-specific: mitophagy

Mitophagy of sperm-derived mitochondria upon fertilization
–unknown why sperm-derived mitochondria are selectively targeted

23
Q

Zygote

A

begins dividing in fallopian tube, implants in uterus as a blastocyst (~100 cells) 710 days post-fertilization

High levels of progesterone limit muscular contractions, so movement through fallopian tube to uterus is slow

24
Q

Blastocyst

A

hollow ball of cells formed as division of zygote continues

Layers:

  • 1) inner cell mass –> fetus
  • 2) trophoblast –> chorion –> placenta
25
Q

Cleavage

A

rapid mitosis, which form small of cells (Morula) - enters uterus about 3 days post-fertilization

begins 30-36 hours after fertilization

26
Q

6 days post-fertilization

A

trophoblast cells secrete enzyme that allows blastocyst to “eat” into endometrium

27
Q

7-10 days post-fertilization

A

blastocyst completely implanted

28
Q

Implantation

A

Between days 7-12, chorion splits into:

  • 1) cytotrophoblast (inner)
  • 2) syncytiotrophoblast (outer)

Developing cytotrophoblast and inner cell mass separated by amniotic cavity

Syncytiotrophoblast secretes protein-digesting enzymes and creates blood-filled cavities in endometrium

Cytotrophoblast sends villi into these pools of maternal blood, forming chorion frondosum

Placental structures are “immunologically privileged site” - barrier preventing direct contact between maternal blood and fetal antigens

29
Q

Fetal part of blastocyst becomes?

A
  1. Endoderm –> gut organs

2. Ectoderm –> skin and nervous system

30
Q

Mesoderm

A

develops later –> muscle, bones and CT

31
Q

Chorion

A

portion of trophoblast layer which becomes embryonic portion of placenta

32
Q

ICM –> ?

A

embryo and extra embryonic membrane, including amnion, yolk sac

33
Q

Placenta and amniotic sac formation

A

As blastocyst develops, endometrium also changes to form decide basalis
-1) joins w/ chorion frondosum to form placenta

part of chorion envelops the growing embryo

  • 1) fluid-filled space between becomes amniotic sac
  • 2) amniotic fluid becomes from isotonic secretion, urine from fetus, and sloughed cells
34
Q

Circulation of blood in placenta

A

Umbilical arteries deliver fetal blood to placental vessels

Blood circulates w/in placenta and returns to fetus via umbilical vein

Maternal blood is also delivered to/from placenta

Thus, maternal and fetal blood do NOT mix; are separated by only 2 cell layers

Molecules (oxygen and nutrients) diffuse across tissues of placenta for exchange, from maternal blood to fetal blood

Carbon dioxide and wastes diffuse from fetal blood to maternal blood

Placenta degrades maternal molecules that may harm fetus

35
Q

Human chorionic gonadotropin (hCG)

A

Secreted from chorionic villi and placenta

Binds to LH receptors on corpus luteum

Maintains viability of C.L., which continues to produce progesterone

By roughly 2-3 months, placenta takes over production of hormones

Progesterone: supports endometrium, inhibits uterine contractions

Estrogen: supports endometrium, development of milk glands

36
Q

From the 2nd trimester-parturition, ____ takes over production of progesterone, estrogen.

A

Placenta

37
Q

What is used in pregnancy tests to determine if pregnancy has occurred?

A

hCG

38
Q

Human placental lactogen (hPL)

A

Secreted by placenta in proportion to placental development

Main function: induce metabolic shift in favor of fetus

decreased maternal sensitivity –> increased maternal blood glucose

decreased maternal glucose utilization –> spares glucose for fetus

increased lipolysis –> increased free fatty acids for use by mother; glucose and ketone bodies used by fetus

*Supports fetal nutrition even under conditions of maternal malnutrition

39
Q

Labor and Delivery

A

roughly 40 weeks

precise initial trigger not clear, but probably due to combination of various factors:

  • 1) secretion of CRH by placenta –> uterine production of prostaglandins –> uterine contractions
  • 2) stretch of cervix induced by baby’s head –> central reflex –> oxytocin secretion –> uterine contractions
  • 3) decrease of progesterone secretion by placenta –> removes inhibition of uterine contractions
40
Q

Mammary gland structure and lactation

A

composed of 15-20 lobes separated by adipose tissue

each lobe made up of lobules composed of glandular alveoli that secrete milk in lactation

milk flows from secondary tubules –> mammary ducts –> lactiferous duct –> nipple

during pregnancy, cortisol, thyroxine, and insulin make mammary glands more sensitive to rising progesterone and estradiol levels

  • -progesterone stimulates alveoli growth
  • -estradiol stimulates tubule and duct growth
41
Q

Control of lactation

A

prolactin from pituitary gland stimulates production of milk proteins, casein and lactalbumin

prolactin is inhibited by PIH (dopamine) from pituitary gland. PIH stimulated by estradiol secretion
–when placenta is shed at birth, estradiol levels drop, lifting inhibition or prolactin

42
Q

Breast feeding and immunity

A

IgG antibodies passed from mother to child in utero

IgA antibodies passed to child from breast milk

  • 1) these provide passive immunity for the first several months of life until baby can develop its own antibodies
  • 2) also promotes development of baby’s own active immmunity
43
Q

Menopause

A

female (usually > 50 years)

cessation of reproduction-competent phase of life - ovulation, menstrual cycles gradually becomes erratic and ultimately cease

appears to be due to development of insensitivity to FSH, LH in ovaries –> decreased production of estrogen, progesterone

44
Q

Symptoms of menopause are due to loss of ____.

A

Estradiol

45
Q

Symptoms of menopause

A

a) hot flashes are produced by vasomotor disturbances
b) walls of urethra and vagina atrophy, and vaginal glands no longer produce lubrication
c) after menopause, risk for atherosclerosis and osteoporosis increases
- -> estradiol is needed for bone deposition, so menopausal women are at increased risk for osteoporosis
- -> adipose tissue does make a weak form of estradiol called estrone. Thus, heavier women have reduced risk of osteoporosis

46
Q

Andropause

A

male

Testosterone production decreases with aging, but precise role of decreased testosterone is not clear, since physical and psychological symptoms of aging in men and have not been clearly linked to a decline in testosterone

Physiology (MPP 3202) (32 decks)

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