Human reproduction, pregnancy and parturition Flashcards Preview

E: Regulatory Physiology & Pharmacology > Human reproduction, pregnancy and parturition > Flashcards

Flashcards in Human reproduction, pregnancy and parturition Deck (54):
1

Name the 4 stages of sexual arousal

  1. Excitement 
  2. Plateau
  3. Orgasm
  4. Resolution

 

2

Difference between male and female sexual arousal

 

See additional sheet.

Males have a refractory period were they cannot be sexual aroused while females do not.

ie females have multiple sexual orgasm.

3

Excitement stage for males?

Heightened sexual awareness

Testicular vasocongestion.

Engorgement of penis (erection)

4

Excitement stage for females?

Heightened sexual awareness.

Vasodilation of vagina and external genitalia (swelling of labia)

Erection of clitoris

Lubrication of vagina.

Enlargement of breasts.

5

Erection reflex?

See additional sheet.

Sympathetic supply and parasymapthetic supply to penile arterioles are in balance to make the penile arterioles dilate.

Sympathetic- outflow of blood.

6

The characteristics of the plateau phase for males?

Intensification of excitement

Increase HR, BP, respiration rate, muscle tension.

7

The characteristics of the plateau phase for the female?

Same as male

vasodilation of lower 1/3 of vagina causes tightening. 

Tenting effect: uterus raises, lifts cervix, englarges upper half of vagina for ejaculation

8

Characteristics of the orgasm phase for males?

Intense physical pleasure.

Ejaculation.

Rhythmic contractions of pelvic muscles.

Increased HR, BP respiration rate, muscle tension

9

Characteristics of the orgasm phase for females?

Intense physical pleasure

Rhythmic contractiosn of pelvic muscles

Increase HR, BP, respiratory rate, muscle tension.

No ejaculation

No refractory period.

10

Name the 2 phases of ejaculation?

Emission

Explusion

11

Emission phase of ejaculation?

production of semen (prostatic fluid, sperm and sv fluid)

Secreted into prostatic urethra

12

Explusion phase of ejaculation?

Motor neurones induce rhythmic contraction 

Semen forced out through urethra

13

Resolution period in males?

Temporaly refractory period (cant have an orgasm in quick succession)

Relaxation

Return of body to pre-excitement state.

14

Resolution period for females?

No refractory period

Relaxation

Return of body to pre-excitement state.

15

Where is the fertilisation site?

Upper third of oviduct.

16

Capacitation?

What does it allow the spermatozoa to do (4 things)?

The reversible, prefertilization activation process of sperm which results in the spermatozoa gaining the ability to:

1. Develop hyperactivated motility, with vigorous nonlinear flagellar motion
2. Bind to the zona pellucida
3. Undergo the acrosome reaction
4. Proceed eventually to fusion with the oolemma and egg fertilization

cAMP levels rise to promote this.

17

Process of fertilisation?

How many stages?

Additional sheet.

5 stages

18

Stage one of fertilisation?

The fertilising sperm penetrates the corona radiata (follicular cells)

Binds to the ZP3 receptors on the zona pellucida via membrane-bound enzymes in its head.

19

Stage 2 of fertilisation?

Binding of sperm to these receptors triggers acrosome reaction

the hydrolytic enymes in the acrosome are released onto the zona pellucida

20

Stage 3 of fertilisation?

The acrosomal enzymes digest the zona pelluicida 

Creates a pathway to the plasma membrane of the ovum

When the sperm reaches the ovum, fusion between the plasma membranes.

21

Stage 4 of the fertilisation pathway?

The sperm nucleus enters the ovum cytoplasm.

22

Stage 5 of fertilisation?

Sperm stimulates release of calcium stores in cortical granules in the ovum.

Inactivates the ZP3 receptors, leading to the block to polyspermy.

23

Allurin?

Released by mature ovum

Chemoattract

Used to attract sperm.

Sperm uses olfactory receptor (hOR17-4).

Detection tail movement and swimming in direction of the signal

24

Fertilin?

Protein on sperm

Bind to integrin 

25

Early stages of development from fertilisation to implantation?

See additional sheet

26

Implantation of the blastocyst?

See additional sheet

27

Stage one of implantation?

Initial contact with epithelium of uterus

Proteases released from tropohblast allowing trophoblast to grow into the endometrium.

Trophoblast releases nutrients for embryo.

28

Stage 2 of implantation?

Trophoblast cells tunnel into the endometiral lining.

Boundaries between trophoblast cells distinegrate become syncytiotrophoblast.

 

29

What day is implantation completed?

Day 12

30

Development of placenta?

Placenta derived from both trophoblast and decidual tissue.

Trophoblast cells differentiate into multinucleate syncutiotrophoblast which invade decidua and break down capillaries to form cavities tfilled with maternal blood.

Developing embryo sends capillaries into the syncytiotrophoblast projections.

 

31

Placenta blood?

Each villus contains foetal capillaries seperated from maternal blood by a thin layer of tissue.

2 way exchanger. 

Functional by week 5

Additional sheet

32

Hormonal maintenance of pregnancy:

1st trimester?

hCG:

produced by the blastocyte.

Prolongs life of corpus luteum (till 10 weeks)

After this, the placenta produces these hormones.

33

Why is it important for the corpus luteum to be there?

Keeps high level of progesterone and oestrogen.

Uterine lining maintained. 

Stops the implanted foetus being swept away with the menstrual lining.

34

What does the graph look like for hormonal maintenace for the pregnancy?

See additional sheet.

35

Why doesnt oestrogen initially come from the placenta?

Placenta does not possess all the enzymes needed for oestrogen synthesis in the 1st trimester.

Requires DHEA from foetal adrenal cortex.

Takes time to develop.

The placenta can synthesise progesterone but only in small amounts.

36

Oestrogen?

Stimulate growth of myometrium musculature

Stimulate development of mammary gland ducts

37

Progesterone?

Suppresses contraction of uterine myometrium.

Promotes formation of mucus plug.

Stimulates development of mammary milk glands

38

Gestation?

Approx 38 weeks from conception.

Mother undergoes physical changes: weight gain, increase nutritional requirement for the mother, enlargement of breasts 

39

What is secreted from the endocrine during gestation?

hCG

Progesterone and estrogen.

hSC (prepare breasts)

PTHrp (mobilises maternal calcium for calification of foetal bones)

Relaxin (softens cervix)

CRH (stimulates DHEA production)

40

Parturition?

Labour, delivery or birth

Requires the dilation of the cervical canal and contractions of uterine myometrium.

41

Name the 4 prepartions for parturition?

  1. Bratox-Hicks contractions (false labour- increased uterine sensitivity)
  2. Softening of cervix: caused by relaxin and prostaglandins allows cervix to dilate during labour.
  3. Relaxation of pelvic bones (caused by relaxin)
  4. Foetus "drops" (head is in contact with cervix)

 

42

What feedback is needed for contractions

Positive feedback loop

See additional sheet.

43

How does increase oxytocin secretion affect the production of prostaglandins?

Oxytocin acts via IP3

Raises calcium levels.

44

How many stages of labour?

45

1st stage of labour?

Cervical dilation stage.

May take many hours

Rupture of amniotic sac: water break.

Cervice dilates to 10cm to accomodate the baby's head.

46

2nd stage of labour?

Delivery of the baby.

Usually takes 30-90 mins.

Baby moves through the cervix to vagina.

 

47

3rd stage of labour?

Delivery of the placenta

Takes 15-30 mins.

Placenta separates from myometrium and uterine contractions caused it to be expelled.

 

48

Involution?

Shrinkage of uterus to pre-pregnancy size

Takes 4-6 weeks.

Because of a fall in oestrogen and progesterone levels (loss of placenta)

Oxytocin released in response to breast feeding

Lochia

49

Development of the breast?

Breast dont fully develop till pregnancy.

Development of glandular structure.

Each duct terminates in a lobule.

50

Lobule?

Made of milk producing glands- alveoli.

Milk secreted from epithelial cells into lumen

51

What triggers development of the breats during pregnancy?

Increase oestrogen (Duct development)

Increase progesterone (lobule formation)

Prolaction and HCS.

 

52

What stimulates milk production?

Prolactin 

 

53

Suckling?

Triggers neuroendocrine reflex

Leads to secretion of prolactin (milk production) and oxytocin (milk ejection)

54

Colostrum?

Milk produced in the first 5 days after birth.

Lots of antibodies.