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MEDSCI142 > Reproductive System > Flashcards

Reproductive System Flashcards

1
Q

Describe how the hypothalamus helps to control the posterior pituitary gland

A

Hypothalamus neurosecretory cells have long axon tracts which pass into the posterior pituitary. From there neurosecretory peptide hormones are made in the hypothalamus and stored in vesicles at the axon terminals. Nerve impulses trigger the opening of these vesicles.

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2
Q

Describe how the hypothalamus helps to control the anterior pituitary gland

A

For the Anterior there are hypothalamic neurosecretory cells that produce releasing and inhibiting hormones which are sent to axon terminus. When nerve impulses cause the vesicles to be released they are secreted into the hypophyseal portal vessels where they act on specific anterior pituitary secretory cells.

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3
Q

What are the two main functions of the gonads

A

To produce gametes and to produce reproductive hormones

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4
Q

How is gonadotrophin secretion regulated in the pathway to produce sex steroid hormones. which are the positive and negative pathways.

A

The hypothalamus releases GnRH (Gonadotrophin releasing hormone) - (a positive signal)which acts on the Gonadotrophs (secretory cells) of the anterior pituitary. This causes it to produce FSH and LH which act on the gonads which bring about the production of sex steriod hormones. These steroid hormones contribute to a negative feedback system on the hypothalamus.

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5
Q

What are the key reproductive hormones and what are the two chemical classes they are under

A

Water soluble : Peptides and proteins such as GnRH, FSH, LH and Oxytocin as well as Lipid soluble: Steroid sex hormones such as Oestrogens, Progestogens, Androgens

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6
Q

Where are the lipid soluble sex hormones produced vs the water soluble sex hormones produced

A

Lipid soluble are in the gonads- Androgens are in testes while others are in ovaries.
Water soluble hormones are mostly from the Ant. Pituitary (LH and FSH). Oxytocin is Post. Pituitary and GnRH is hypothalamus

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7
Q

What are the main androgens and what are the key properties

A

Testosterone, 5-a- Dihydrotestosterone. These promote and maintain male sex development, spermatogenesis, sexual behaviour (also in females) and muscle development

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8
Q

What are the 3 oestrogens, where are they produced

A

Oestradiol- the main hormone produced by granulosa cells of growing follicle, in puberty onwards Oestrone- produced throughout life, from fat tissue, produced by men and dominant post menopause. Oestriol- produced by the placenta prior to labour helping the softening of the cervix.

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9
Q

What are the key properties of oestrogens

A

They promote and maintain female sex development and fertility. They regulate the menstrual cycle and are involved in the growth of endometrium and bone growth.

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10
Q

What are the main progestogens and what are the key properties

A

Progesterone is the major steroidal hormone of the corpus luteum and of the placenta. It is associated with the preparation and maintenance of a pregnancy

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11
Q

What is sex determination vs sex differentiation

A

Sex determination is the commitment of bipotential gonad to testis or ovary in the genotype whereas Sex differentiation is the phenotypic development of the genital structures due to the action of hormones produced by the gonad present.

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12
Q

How does sex determination happen

A

There is a sex determining region on the Y chromosome (SRY) that provides a pathway for the testes to develop. The presence of a testis drives the sexual fate of the embryo against the basic feminine trend. In absence or mutation of SRY the embryo develops into a female

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13
Q

What are the key events of sex differentiation for internal genitalia for females

A

Ovary will produce oestrogens and progestogens. There is spontaneous regression of the wolffian ducts. The mullerian ducts persist, developing to give rise to fallopian tubes, uterus, cervix and upper vagina.

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14
Q

What are the key events of sex differentiation for internal genitalia for males

A

The testes will produce sertoli cells which produce Anti Mullerian hormone. This drives the regression of the female system. Leydig cells secrete testosterone which actively maintain the wolffian ducts and leads to development of epididymis, vas deferens, and seminal vesicles.

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15
Q

What is the kind of time difference between development of the internal organs of males and females

A

Female differentiation lags behind Male organogenesis as male one is a driven process. The testis descends from its internal position to the scrotum usually after the 7th month.

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16
Q

Describe the main external features of the bipotential precursor (undifferentiated stage)

A

Outer layer is the labioscrotal swelling, with the urethral folds and a urethral groove in the middle and on top, a genital tubercle

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17
Q

What are the key events of sex differentiation for external genitalia for males

A

The shaft of the penis is made from urethral folds fusing together to enclose a urethral tube.
The scrotum comes from the labioscrotal swellings fusing at the midline.
The glans penis is formed when the genital tubercle swells

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18
Q

What are the key events of sex differentiation for external genitalia for females

A

The labia minora (inner) is formed from urethral folds staying separate and the labia majora (outer) are formed by the labioscrotal swellings staying separate. The clitoris forms from the genital tubercle.

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19
Q

What is puberty

A

The physical and behavioural changes associated with the sexual transition from childhood to adulthood where the reproductive endocrine systems are reawakened from when they were first active in the development of the embryo

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20
Q

What is the first endocrine sign of puberty and what causes it.

A

An increase in LH plasma levels due to the increase in GnRH release from the hypothalamus acting on the pituitary. As a result there is a rise in sex steroid hormones.

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21
Q

When does the first endocrine sign of puberty happen throughout puberty

A

In early puberty GnRH, and therefore LH (+FSH) levels increase during sleep. In late puberty daytime LH pulses also increase

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22
Q

What is the purpose of the (Tanner stage) staging criteria of secondary sexual characteristic

A

These characteristics develop at different chronological ages in different individuals but their sequence is usually the same so this allows abnormalities to be detected and comparisons to be made between individuals

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23
Q

What is the sequence of the 4 major events during puberty for females

A

1st: development of breasts
2nd: Pubic hair
3rd: Peak height spurt
4th: Menarche

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24
Q

Describe the development of the breast- when does it first start, what hormones involved

A

Starts age ~10-11.
First Oestrogen causes a breast bud to start, followed by the breast mound.
Full breast development then happens when ovulation causes the release of progesterone

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25
Q

Describe the development of sexual hair in females- when does it first start, what hormones involved

A

It starts within 6 months of the appearance of the breast bud (~10/11)
This is due to exposure of hair follicles to androgens.
Axillary (armpit) hair follows 1 year after pubic hair

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26
Q

What is indicated by pubic hair before breasts in females

A

An androgen disorder.

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27
Q

Describe the development of the Growth Spurt in females- when does it first start, what hormones involved

A

Peak growth occurs in girls age 11,12. This is stimulated by both steroid hormones. This growth process is then slowed steeply over time with epiphyseal closure of the bony ends caused by oestrogen.

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28
Q

Describe the development of Menarche and Ovulation- when does it first start, what hormones involved

A

Menarche starts at 12-13 years, and ovulation doesn’t take place until 6-9 months after menarche because the positive feedback mechanisms of oestrogen haven’t developed

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29
Q

When are regular ovulatory cycles established

A

1-2 years are first menstrual bleed

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30
Q

What is the sequence of the 4 major events during puberty for males

A

1: Growth of the Testis- testicular and penile enlargement
2: Pubic hair
3: Growth of Penis
4: Height spurt

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31
Q

Describe Testicular and penile enlargement- when does it first start, what hormones involved

A

Starts 10-13.5. Caused by Leydig cells enlarging and secreting testosterone giving rise to increased testicular size. Testosterone causes elongation and enlargement of the penis begins within a year of testicular enlargement

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32
Q

Describe the development of sexual hair growth in boys when does it first start, what hormones involved

A

Starts about 6 months after the beginning of testicular enlargement, with axillary hair beginning 18 months later and facial hair later. Caused by androgens

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33
Q

Describe the event of spermarche- when does it occur

A

This is the beginning of spermatogenesis. Motile sperm is seen in urine at 13-14 years. The first ejaculation occurs soon after

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34
Q

What is spermarche the equivalent to in females

A

ovulation

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35
Q

What is the trend in the timing of Menarche?

A

There is a trend towards earlier ages of Menarche. this may be because a critical weight (~47kg) must be attained before the activation of the hypothalamo-pituitary-gonadal axis can occur. This signifies that sufficient storage is required to sustain pregnancy and lactation.

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36
Q

Define precocious puberty

A

The appearance of physical and hormonal signs of puberty before
7 in girls
9 in boys.

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37
Q

What are causes of precocious puberty

A

This is due to release of GnRH, in extreme cases caused by hypothalamic tumour.

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38
Q

Define delayed puberty

A

The lack of appearance of physical and hormonal signs of puberty at
13 in girls
14 in boys

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39
Q

What are the causes of delayed puberty

A

The gonadotrophin signals from the pituitary are inadequate for sex steroid secretion

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40
Q

How is the point of Menopause measured in time

A

The last menstrual bleed

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41
Q

Why does menopause occur and when does it occur

A

Menopause happens because the ovaries run out of viable follicles. This occurs between 50-52

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42
Q

What are the 5 different phases of end of reproductive life as a woman

A

Premenopause, menopausal transition, post menopause, ovarian senescence and perimenopause

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43
Q

Describe Pre-menopause phase

  • where does it start and end
A

Starts from early 40s until ~46. During this period she still has regular periods

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44
Q

Describe Menopausal Transition

  • where does it start and end
A

Starts from ~46 til 50/52 (Menopause). During this time her periods become irregular as some follicles may not respond. Cycles can become longer.

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45
Q

Describe Post Menopause

A

This is from 50-52 years onwards after the last menstrual bleed

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46
Q

Describe Ovarian senescence - where does it start and what happens because of it

A

~ 1 year after menopause the ovaries stops producing hormones. This means that oestrogen production reduces to 1/10 of what it used to be. The main source of oestrogen is now from Oestrone produced in stromal cells of adipose tissue.

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47
Q

Describe the phase of perimenopause

A

Refers to the time ‘around menopause starting at menopausal transition until ovarian senescence. During this period perimenopausal symptoms of oestrogen deprivation occur

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48
Q

List the main perimenopausal symptoms

A

Vasomotor: fluctuations in blood vessels leading to overheating- hot flushes/night sweats

Genitourinary: Vaginal dryness due to reduced secretion, and atrophic changes

Bone Metabolism:
- increased risk of bone disease and weakness

Behavioural and Psychological:
-Depression, tensions, anxiety, mental confusion and loss of libido

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49
Q

Describe the vagina structure and function

A

This is the muscular 7.5-9 cm long tube that extends from the cervix to the exterior of the body.
It has 3 main functions: receives the penis, holds spermatozoa before they pass into the uterus and forms the lower portion of the birth canal

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50
Q

Describe the Uterus function

A

Function is to provide mechanical protection, nutritional support and waste removal for the developing fetus.

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51
Q

Describe the layers of ‘metrium’ in the uterus

A

Outermost layer is the stratum functionalis which contains the uterine glands and is lost throughout menstruation. Then the stratum basalis which stays constant and is attached to the myometrium. Myometrium is a smooth muscle wall that’s contractions help expel the fetus.

52
Q

Describe the Fallopian (uterine) tubes structure (basic)

A

The tube is lined by epithelium made up of ciliated and nonciliated secretory columnar cells. The mucosa is surrounded by concentric layers of smooth muscle.

53
Q

Describe the Fallopian (uterine) tubes function

A

Function: transport of spermatozoa, oocyte and embryo by ciliary movement and peristaltic contractions. As well as having lipids and glycogen for a nutritive environment.

54
Q

Describe the Ovaries structure and function

A

Oval organ about 5-10g comprising of 3 regions.
Outer ovarian cortex containing all ovarian follicles, the central ovarian medulla (which contains ovarian stroma and steroid producing cells) and the inner hilum which allows blood vessels and nerves to enter.

55
Q

What is ovarian stroma

A

A dense irregular connective tissue

56
Q

What does an anteflexion or retroflexion mean

A

Most women have an anteflexed uterus which is perpendicular to the vagina but 20% have a retroflexed uterus which is kind of straight, following the vaginal tube

57
Q

Describe the structure of the Uterus

A

Pear shaped organ 30-40g. The top part is called the Fundus and the bottom is called the Cervix.

58
Q

What is the function of cervical mucus

A

Most of the time cervical mucus becomes thick plugging the cervix so no bacteria or sperm can enter the uterus from the vagina. Only a few days prior to ovulation does the mucus change to allow the entry of sperm

59
Q

How was fetal growth predicted in the old days

A

The height of the fundus from the pubic bone was used to predict the number of weeks a fetus had gestated. With 1cm = 1 week. It could be also used to check for twins, gestational diabetes, wrong position, intrauterine growth restriction

60
Q

Describe the 4 kind of regions of the fallopian tube

A

Closest to the uterus is the Isthmus.
Middle where fertilisation occurs: Ampulla
End Closest to the ovary :infundibulum.
Fingerlike projections at end : fimbriae. These are covered in cillia that are beating constantly and increase frequency to collect the oocyte when ovulated.

61
Q

Define ectopic pregnancy

A

When fertilised embryo is implanted in any tissue other than uterine wall

62
Q

List the 5 steps of follicular development in order and the two possible outcomes

A

Primordial follicle, primary follicle, secondary follicle, Mature (Graafian/pre-ovulatory follicle)
Ovulation, Corpus Luteum (luteinisation)
OUtcomes:
Fertilisation & futile

63
Q

Describe the primordial follicle stage

A

The ovaries are filled with millions of primordial follicles from birth. These are oocytes surrounded by a single layer of squamous follicular cells.

64
Q

Describe the Primary- Pre antral follicle stage

A

Some follicles grow and others die. The ones that start to grow, follicular cells become one layer of cuboidal granulosa cells

FSH stimulates the oocyte to get bigger and then get more layers of granulosa cells.
Oocyte secretes glycoproteins which form a translucent layer called the Zona pellucida.
Ovarian stroma cells called Thecal cells begin to form around the follicle

65
Q

Describe the main events at the Secondary follicle stage

A

As granulosa cells proliferate, they produce a viscous follicular fluid that coalesces to form a single follicular antrum (lake).

Granulosa cells specialise
Theca develops into 2 layers

66
Q

What happens to the granulosa cells at secondary follicle stage

A

The corona radiata is made from the inner most 2-3 layers of granulosa cells becomes firmly attached to the zona pellucida.
The rest of the loosely associated granulosa cells are called cumulus oophorus

67
Q

What does the theca develop to at the secondary follicle stage

A

The thecal cells move from the medulla to form the inner glandular and highly vascularised theca interna ( involved with the increased production of estradiol) and the fibrous outer capsule called theca externa

68
Q

Describe main events in the mature (Graafian or preovulatory) follicle stage

A

The follicular antrum grows, the oocyte becomes suspended in fluid.
It is connected to the rim of peripheral granulosa cells by a thin stalk of cells

69
Q

Describe main events in the ovulation stage

A

The follicle starts to bulge out the ovarian surface bc it gets larger and its at the cortex of the ovarian stroma.

The follicle then ruptures and this slowly releases the oocyte+ surrounding mass of cumulus cells.
The oocyte is collected by cillia on the fimbria which sweep the cumulus mass into the uterine tube

70
Q

Describe main events in the Corpus luteum (luteinisation) stage of the ovary

A

After ovulation, the antrum breaks down and the basement membrane between the granulosa and theca layers breaks down and blood vessels invade.
2. The granulosa cells form lutein (yellow) cells, this is associated with increasing secretion of progestogens

71
Q

Describe what happens to corpus luteum in a futile cycle

A

Corpus luteum will only stay for 2 weeks. After which no fertilisation will lead to degeneration, forming the corpus albicans which is absorbed back into the stromal tissue of the ovary over weeks to months.

72
Q

Describe what happens to corpus luteum in a fertile cycle

A

The corpus luteum will persist if the zygote survives and divides. hCG produced by chorion of the embryo 8days after fertilisation stops deterioration of the corpus luteum. This allows it to keep producing progesterone + estrogen to support pregnancy

73
Q

What is the difference between a futile cycle and fertile cycle

A

Futile will lead to corpus luteum degenerating and therefore no more progesterones to prepare stable secretory endometrium for implantation as in a fertile cycle. Instead it is shed in menstruation.

74
Q

Name and compare the phases of the ovarian cycle vs the endometrial cycle

A

The ovarian cycle has 2 phases, follicular phase (day 1 to ovulation) and luteal phase (ovulation to menstruation).
In contrast, the uterine menstrual cycle has 3 phases: Menstruation (0-5) proliferative in response to estradiol and secretory in response to progestrone

75
Q

what cells produce what estrogens in the ovaries

A

The granulosa cells around the chosen oocyte. This is estradiol

76
Q

What is the fixed phase of the menstrual cycle - how long and therefore how can menstrual cycle length vary

A

luteal phase is a fixed 14 days, however as a women ages the length of the follicular phase changes

77
Q

Why does a human need a menstrual

A

The female reproductive tract has 2 main functions. To produce oocyte and reproductive hormones. And as well to incubate embryo

78
Q

What is the first 2 key events of menstrual cycle ( starting at just before the menstrual bleed)

A
  1. The corpus luteum regresses with oestrogen and progesterone levels low. There is a slight increase of FSH
  2. FSH stimulation leads to increase follicular growth
79
Q

What is the #3,4 key events of menstrual cycle ( starting at day 6/7)

A
  1. The dominant follicle has been selected. it has lots of thecal and granulosa cells that produce a rise in oestradiol
  2. Oestradiol suppress FSH and LH production in the pituitary
80
Q

The levels of Progesterone and oestrogens increase and decrease oppositely to which two other hormones

A

FSH and LH

81
Q

What is the #5,6,7 key events of menstrual cycle ( starting at around day 12)

A
  1. Oestrogen levels by the nearly mature follicle rise by ~day 12, a theshold concentration of oestradiol is exceeded. If this is maintained for around 3 days, there is a temporary switch from a negative to positive feedback.
  2. Oestrogen mediated positive feedback triggers a rise in GnRH, leading to a surge in LH
  3. The rapid rise of LH induces ovulation- release of the oocyte
82
Q

What does the positive feedback switch caused by oestrodial mean

A

Instead of oestrodial increasing causing a decrease in GnRH and LH/ FSH, instead it helps to stimulate both the hypothalamus and anterior pituitary to produce MORE GnRH and LH/FSH

83
Q

What is the #8,9,10 key events of menstrual cycle (starting at around day 17)

A
  1. Corpus Luteum develops and this increases progesterone.
  2. Elevated progesterone levels inhibit GnRH, leads to decreased FSH + LH as it reinstates the negative feedback loop
  3. The Corpus luteum demises and therefore progesterones start to decrease
84
Q

Where does spermatogenesis take place and when during the lifetime of males does it take place

A

In seminiferous tubules of the 2 testes. It takes place at the onset of puberty where 300/600 sperm per gram per second.

85
Q

What are the three stages of spermatogenesis

A
  1. mitotic division
  2. Meiotic division
  3. Cytodifferentiation
86
Q

Describe the first step of spermatogenesis stage of mitotic division + where it occurs

A

At puberty the spermatogonial stem cells (primordial germ cell) that sit on the basement membrane of the seminiferous tubule are reactivated. They undergo the 1st asymmetric mitotic division where 1 daughter cell remains undifferentiated to maintain the stem cell population and the other daughter cell continues to divide by mitosis, forming a number of spermatogonia. This happens in the basal compartment of the seminiferous tubule.

87
Q

where do the spermatogonia migrate before first meiotic division

A

They migrate from basement membrane between the adjacent sertoli cells held together by tight junctions into the Adluminal compartment of the seminiferous tubules

88
Q

Describe the 2nd step of spermatogenesis stage 1 of meiotic division + where it occurs

A

Spermatogonia now are called primary spermatocytes in the adluminal compartment. They undergo meiosis I. this leads to DNA content doubled so each spermatocyte has 46 chromosomes. The primary spermatocytes then divide to produce secondary spermatocytes with only 23 chromosomes but with each chromosome having two chromatids.

89
Q

Describe the 3rd step of spermatogenesis stage 2 of meiotic division + where it occurs

A

Secondary spermatocytes undergo meiosis 2 to give 4 daughter spermatids each with 23 chromosomes

90
Q

Describe the 4th step of spermatogenesis (spermiogenesis) + where it occurs

A

Round spermatids differentiate their shape and become elongated spermatozoa. The excess cytoplasm of the spermatid is also lost into a structure called the residual body which is phagocytosed by the sertoli cells after the sperm leaves to the lumen of the seminiferous tubules.

91
Q

Describe the structure of the spermatozoa

A

The head contains DNA and is covered by acrosome which is a compartment filled with enzymes for egg penetration.
The midpiece is packed with mitochondria to produce energy to drive the tail

92
Q

In the absence of testosterone in the seminiferous tubules what will happen to spermatogenesis

A

Without testosterone spermatogenesis commences but it doesn’t finish. We need a high level of testosterone in the testes to produce mature sperm

93
Q

Compare Sertoli and Leydig cells: Location, what acts on it, what does it produce

A

Sertoli cells are inside the seminiferous tubules, closer to the basement membrane. Whereas Leydig cells are interstitial cells outside the seminiferous tubules. Sertoli cells are acted on by FSH and produce Androgen binding protein as well as inhibin whereas Leydig cells are acted on by LH and they produce testosterone

94
Q

What are the hormones involved in the negative feedback system of sertoli and leydig cells

A

Testosterone by leydig cells inhibits the hypothalamus and anterior pituitary whereas inhibin produce by sertoli cells acts on only FSH production

95
Q

What are the 3 types of male fertility

A

Oligospermia: Reduced sperm count (below 20 million/mL)
Azoospermia: No sperm
Immotile sperm: Plenty of sperm but sperm can’t swim

96
Q

Describe IVF (in vitro fertilisation)

A

The oocytes are harvested, kept in a petri dish with some embryo culture medium and fertilised ex vivo, with the 50 000 motile sperm injected into the droplets. Embryo is then reimplanted to the mother

97
Q

Describe ICSI (intracytoplasmic sperm injection)

A

A single sperm (This technique works for sperm harvested from biopsy of epididymis, motile or not) is injected directly into the oocyte using a micropipette. While this is happening there is a holding pipette holding the oocyte still

98
Q

What are the testicles:

  • what is the plural and and singular form of the testicles. - where are located and where do they form
A

Humans have 2 testis (singular) that are called Testes or testicles.
They are located in the scrotum, but form in the abdominal cavity and prior to birth descend through the inguinal canal to the scrotum

99
Q

What is the term for a male whose testes do not descend. What does this cause them

A

Cryptorchidism. This causes them to be infertile and prone to testicular cancer

100
Q

What is the greek root for testes

A

Orkhis

101
Q

Describe the course of sperm as it traverses the male reproductive tract

A

Mature sperm produced in the seminiferous tubules fall off into the liquid produced by the seminiferous tubules, moving down into the Rete Testis. These drain into a single duct at the tail of the epididymis. Sperm then go to Vas Deferens which runs from the caudal end of the epididymis through the inguinal canal, looped back up and over the bladder and joins to the ejaculatory duct. Then sperm travel down the ejaculatory duct through the prostate to the urethra to tip of penis

102
Q

What is the Rete testis

A

Centrally placed duct system in the testes that connects the seminiferous tubules to the epididymis.

103
Q

What does the seminiferous tubules in the testes look like

A

There are ~80 convoluted tubes in testes

104
Q

What is the epididymis structure location

A

It runs around the outside of the testicle from the top to the bottom containing the ductus epididymis where sperm keep maturing.

105
Q

What happens to the sperm when it enters the epididymis and how long are they there for

A

Sperm spend 10-14 days passing through the epididymis to acquire the ability to be motile and to fertilise. The epididymis also absorbs liquid produced from the seminiferous tubules from around the sperm, increasing the concentration of the sperm.

106
Q

What is the structure and function of vas deferens

A

The Vas deferens are 45cm long they run from the epididymis up through the inguinal canal then up and around the bladder (going behind) then, approaching the prostate gland from behind join back down to the ejaculatory duct. They are the major site of sperm storage where sperm can be stored for months.

107
Q

What is the ampulla of ductus vas deferens

A

It is the widening of the duct just before it opens to the ejaculatory duct. At this site there is much more concentrated sperm storage.

108
Q

Compare the structure and function of the ejaculatory duct with the Urethra

A

Long tube that runs from the end of the vas deferens, through the prostate gland to the urethra.
The Urethra is a 20cm long tube that runs from the bladder, through the prostate and to the end of the penis.
Both ducts cross at a T junction in the prostate gland.

109
Q

What is the structure and function of the seminal vesicles

A

They are secretory glands that secrete a mucoid substance which is emptied into the ejaculatory duct directly after sperm is ejected from the vas deferens, which washes it down.

110
Q

What is the characteristics of the secretion of the seminal vesicles

A

A sticky substance that is:
Alkaline, containing fructose as an energy source for sperm, containing prostaglandins which may induce contractions in the female reproductive tract and contains clotting proteins which helps sperm to stick to the female reproductive tract and not be removed by intercourse

111
Q

What is order of components of the ejaculate

A

Seminal fluid 2. Sperm. 3. Prostatic fluid (technically sperm first)

112
Q

Describe structure and function of the prostate gland

A

A doughnut shaped organ, that is golf ball sized. It secretes prostatic fluid into the urethra ahead of sperm during ejaculation

113
Q

What is the characteristics of the secretion of the Prostate

A

Slightly acidic.
Contains Citrate (for ATP)
Milky colour bc it
Contains phosphate + calcium
Prostate specific antigen and other enzymes to break down the coagulum

114
Q

How does the two secretions make a good pH for the sperm (7.5)

A

The seminal vesicle secretion is slightly alkaline, while the prostatic secretion is slightly acidic (6.5) and these neutralise each other, forming a buffer

115
Q

What is the volume % of components of semen. what is the range of volume for ejaculate

A

Total volume: 1.5-5 mL
10% Sperm
60% Seminal vesicle fluid
30% Prostatic fluid
Other secretions have small amounts.

116
Q

Describe how Benign prostatic hyperplasia happens

A

There is excess growth of the prostatic tissue, but as it is encapsulated it cannot expand that much outwards. This causes some occluding of the urethra

117
Q

What is the consequences of benign prostatic hyperplasia

A

There is difficulty in voiding the bladder. This eventually causes weakening of the bladder and can lead to urinary infections ascending the tract, leading to infection in the kidneys

118
Q

What is the incidence of Benign Prostatic Hyperplasia

A

It is rare in men <40, but from 50 onwards it increases from 17% to 35% and in men over 85 there is 90%.

119
Q

How is Benign Prostatic hyperplasia treated

A

-Surgery on the prostate gland,
- Selective 5alpha reductase inhibitors such as Finasteride and dutasteride which stop the prostate enlarging or shrink it as they stop testosterone being converted to DHT
- Prostatic urethral lift
(where metal wire with hook introduced in the urethra hold the gland to the side to make the urethra bigger.

120
Q

Describe the incidence of Prostate cancer and how it is detected

A

It is the most common cause of cancer deaths worldwide, but only 29% of all cases of cancer. It affects older men. It is detected for looking for Prostate specific antigen in blood.

121
Q

Why does better detection of prostate cancer doesn’t lead to more survivals

A

There is some over diagnosis, most of the time prostatic cancer isn’t bothering the patient and there is a lot of false positives of the screening too. As a result of prostatectomy, there is some side effects: erectile dysfunction, 1 death, urinary incontinence

122
Q

What are some treatments for prostate cancer

A

Watchful waiting

Androgen depletion by 5a reductase inhibitors, castration or inhibitors of androgen synthesis
Inhibition of testosterone action- (blocking the receptors)
Surgery: prostatectomy (removal of the prostate gland)

123
Q

what are the 3 major structures of the penis and their function

A
  1. Corpora cavernosa x 2 which are the main erectile tissues
  2. Corpus spongiosum which surround the penile urethra and prevents occlusion during erection
  3. Penile urethra which conducts semen (and urine)
124
Q

What are the events that cause erection

A

A
Following sexual stimulation

Eelease of NO and Prostaglandin E1 causes the smooth muscle of the corpora cavernosa to relax

Blood fills the cavernous spaces of the corpora cavernosa (8x more than flaccid)

Engorgement of the corpora occludes the venous draining, which keeps it engorged

125
Q

How does Viagra work

A

It inhibits the enzyme #5phosphodiesterase which breaks down GMP ( a 2nd messenger that helps smooth muscle relax by reducing intracellular Ca2+). This leads to increase GMP and therefore relaxation of arteries that supply the corpora cavernosa and erection

MEDSCI142 (9 decks)

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