Pregnancy Flashcards
Approximately what proportion of ejaculated spermatozoa make it as far as the ampullae of the fallopian tubes?
0.001%
Which of the following hormones are responsible for mammary hypertrophy during pregnancy?
Oestrogen
Progesterone
Human Placental Lactogen (hPL)
Prolactin
All 4
The acrosome reaction is triggered by which of the following?
-emission
-binding of the spermatozoa to the zona pellucida
-binding of the spermatozoa to the corona radiata
-binding of the spermatozoa to the oocyte membrane
-fertilisation
binding of the spermatozoa to the zona pellucida
The exocytosis of neurotransmitter from an axon terminal during synaptic transmission is remarkably similar to which of the following?
-fast block to polyspermy
-Frankie Sinatra
-acrosomal reaction
-binding of the spermatozoa to the zona pellucida
-slow block to polyspermy
slow block to polyspermy
An increase in the Na+ permeability of the oocyte membrane is a feature of which of the following?
-slow block to polyspermy
-polyspermy
-acrosomal reaction
-capacitation
-fast block to polyspermy
fast block to polyspermy
During fertilsation penetration of the corona radiata is enabled by which of the following processes?
Cooperative action of spermatozoa.
Enzymes associated with plasma membrane.
The acrosomal reaction.
1 and 2
Which of the following hormones is involved in parturition?
human chorionic gonadotropin
oxytocin
prolactin
2
How many days following ovulation does implantation begin?
6 - 8 days
The movement of spermatozoa from the vagina to the ampullae of the fallopian tubes is greatly enhanced around the time of ovulation by?
Human chorionic gonadotropin
Oestrogen
Progesterone
2
The structure which grows into the endometrium by digesting endometrial cells during blastocyst implantation in known as a?
syncytiotrophoblast
What are the 3 mechanisms that assist with fertilisation
Motility of spermatozoa, thinning of cervical mucus, uterine contractions
What is fertilisation stages?
Penetration of corona radiata (breaking down follicular cells), binding to zona pellucida(glycoproteins prevent cross-contamination), acrosome reaction(enzyme release breaking down zona pellucida), binding to oocyte membrane (plasma membranes fuse and spermatozoon nucleus in oocyte cytoplasm)
What is fast block mechanism?
Within a few seconds of a spermatozoon binding to the oocyte, Na+ channels in the oocyte membrane open allowing Na+ ions to flow down their concentration gradient into the oocyte and thus depolarise the membrane from a resting value of -70 mv to around +10 mV This rapid depolarisation of the oocyte temporarily prevents any further spermatozoa from binding to it.
What is slow block mechanism?
Within a few seconds of the fusion of the spermatozoon and oocyte membranes there is a marked increase in the permeability of the oocyte membrane to Ca2+. As a result Ca2+ flows into the cell and triggers a large number of granules lying just underneath the plasma membrane (known as cortical granules) to fuse with the membrane and exocytose their contents. The enzymes released from the cortical granules hydrolyse the glycoproteins of the zona pellucida and within 30 seconds turn it into an impenetrable barrier and producing a long term block to polyspermy.
What does human chorionic gonadotropin (hCG) do?
Hormone that stimulates the corpus luteum to continue to secrete oestrogen and progesterone. Because it is the decline in progesterone levels that stimulate the menstrual phase of the uterine cycle, menstruation is prevented and thus the endometrium containing the blastocyst is retained. Secreted by trophoblast
What is included in control of partuition?
-Oestrogen stimulates the expression of connexin in the smooth muscle cells of the uterus
-Oestrogen causes a marked increase in the expression of oxytocin receptors on the smooth muscle cells on the uterus
-Oestrogen stimulates the production of enzymes that break down the cross bridges between the collagen fibres in the walls of the cervix and thus increases its flexibility
-Increases the flexibility of the joint between the pelvic bones
All 4
What is the stages of lactation?
Mammary glands with 20 lobes. Each lobe separated by connective or adipose tissue and is made of epithelial glands which is functional units of lactation. Milk flows out through lactiferous ducts. Epithelial glands branch during puberty and at ovarian cycle, high levels of progesterone present at luteal phase stimulate alveoli growth which synthesises breast milk. Mammary glands grow during pregnancy and under the influence of oestrogen, progesterone, human placental lactogen (hPL) and prolactin the tubular ducts and alveoli undergo significant hypertrophy and fat is deposited between the secretory tissues
How does breast milk become available by suckling?
Milk goes from alveoli to lactiferous ducts by contraction of myoepithelial cells in alveoli that contract and squeeze milk into ducts (milk let-down). Mediated by reflex release of oxytocin in response to suckling. Mechanoreceptors in the nipple detect suckling and this information is relayed to the hypothalamus. After a short delay oxytocin is released from the posterior pituitary into the circulation and thereby triggers contraction of the myoepithelial cells and milk let-down. Prolactin needed by anterior pituitary gland for milk production
What does breast milk contain?
For the first few days following parturition the fluid produced by the mammary glands is relatively low in fats and carbohydrates but rich in protein, mineral, some vitamins and immunoglobulins. This fluid is called colostrum and the immunoglobulins provide the new born with some protection against infection. Over the next couple of weeks the fat and carbohydrate levels of the fluid gradually increase as it develops into mature milk.
