12. Reproductive System Flashcards
1
Q
Reproduction: definition
A
The production of new offspring
2
Q
What does sexual reproduction involve?
A
Meiosis
Fertilisation
3
Q
What happens in meiosis?
A
This produces male (sperm) and female (ova) gametes
These are haploid so have 23 chromosomes each
4
Q
What is genetic variability?
A
Offspring having a mix of genes inherited from each parent
5
Q
What does fertilisation produce?
A
A zygote
This contains 46 chromosomes
6
Q
Functions of the reproduction system: female
A
Formation of ova (female gametes) Reception of spermatozoa (male gametes) Provide suitable environment for fertilisation/foetus Parturition (childbirth) Lactation
7
Q
Functions of the reproduction system: male
A
Production of spermatozoa (male gametes)
Transmission of spermatozoa to the female
8
Q
What are breasts?
A
Accessory glands of the female reproductive system
9
Q
What is a mammary gland?
A
A modified sweat gland that produces milk
Found in breast
10
Q
What does each mammary gland consist of?
A
15-20 lobes separated by adipose tissue
Each lobe contains small, grapelike clusters of glands called alveoli
11
Q
What are suspensory ligaments?
A
These support the breast between the skin and the underlying fascia
12
Q
What happens during lactation?
A
Myoepithelial cells surrounding the alveoli contract and propel milk into the lactiferous ducts
13
Q
Where can milk be stored?
A
In the lactiferous sinuses
14
Q
What does prolactin do?
A
Stimulates the production of milk
15
Q
What does oxytocin do?
A
Causes milk ejection during suckling
16
Q
What does the uterus do?
A
Pathway for sperm
Site of zygote implantation
Location for foetal development
Contracts to initiate labour
17
Q
What is a zygote?
A
Fertilised egg
18
Q
Uterus walls: layers
A
- Perimetrium
- Myometrium
- Endometrium
19
Q
Perimetrium
A
The outer layer of the uterus wall
20
Q
Myometrium
A
The middle layer of the uterus wall
Has 3 layers of smooth muscle
21
Q
Endometrium
A
The inner layer of the uterus wall High vascular (rich supply of blood vessels) Divided into the: 1. Stratum functionalis 2. Stratum basalis
22
Q
Stratum functionalis
A
Layer of the endometrium that sloughs off during menstruation
23
Q
Stratum basalis
A
Permanent deeper layer of the endometrium
Regenerates the stratum functionalis ready for the implantation of a fertilised egg (zygote)
24
Q
Uterus: anatomy
A
Fundus (top bit)
Body (hollow bit)
Cervix (narrow bit)
Size and shape of a pear
25
Broad ligament
This holds the uterus and ovaries in place
26
Uterus: location
Situated between the bladder (anterior) and the rectum (posterior)
27
What is an embryo?
An embedded zygote <8 weeks
28
What is a foetus?
An embryo >8 weeks
29
Placenta: functions
Allows oxygen and nutrients to diffuse from maternal blood into foetal blood
Allows carbon dioxide and waste to move in the opposite direction
Produces hormones that are needed to maintain the pregnancy
30
What is the placenta attached to?
The endometrium
31
Why is the placenta unique?
By the beginning of the 12th week, it contains 2 distinct regions from two individuals
32
What is the umbilical cord?
Connects the placenta to the embryo/foetus
Around 50-60cm long
33
What can't pass through the protective barrier in the placenta?
Blood cells
| Most micro-organisms
34
What can pass through the protective barrier in the placenta?
```
HIV
Measles
Polio
Chicken pox
Alcohol
Drugs
```
35
What controls the transfer of nutrients to the foetus?
Proteins called nutrient transporters
36
Placenta: hormones
```
Progesterone
Oestrogen
Human Chorionic Gonadotrophin (hCG)
Human Placental Lactogen (hPL)
Relaxin
Corticotrophin Releasing Hormone (CRH)
```
37
Progesterone
Maintains endometrial lining to sustain and nourish the foetus
Produced by corpus luteum until 8 weeks
38
Oestrogen
Promotes growth of breast tissue and myometrium
Produced by corpus luteum until 8 weeks
39
Human Chorionic Gonadotrophin (hCG)
Only produced during pregnancy
Maintains corpus luteum for 8 weeks and increases transfer of nutrients to foetus
Related to morning sickness
40
Human Placental Lactogen (hPL)
Increases the amount of glucose and lipids in the maternal blood
41
Relaxin
Targets ligaments and relaxes them
Produced by the corpus luteum and then placenta
42
Corticotrophin Releasing Hormone (CRH)
Triggers release of cortisol from the adrenal glands
Prevents rejection of foetus/placenta (as seen as 'foreign invaders')
43
Placenta Praevia
When the placenta attaches to the lower part of the uterine wall
44
Risks of placenta praevia
Obstructing the opening of the cervix (more risk with multiple births as more placentas present)
45
When is it possible for placenta praevia to resolve itself?
During 1st trimester
46
What can happen in placenta praevia during the 2nd and 3rd trimester?
Prone to haemorrhage
Wall of cervix stretches and can detach from placenta
Uterine vessels rupture and cause ante-partum vaginal bleeding
47
What is the treatment for placenta praevia in the later stages?
C-section
48
Placenta Accreta
Abnormally deep attachment of the placenta through the endometrium into the myometrium
49
Increta
If the placenta invades the myometrium
50
Percreta
If the placenta goes through the uterine wall to surrounding viscera e.g. the bladder
51
What causes placenta accreta?
Thin, inadequate stratum basalis in endometrium
Placenta has to dig deeper when implanting
Due to previous C-section, scrapping procedure, fibroid removal, placenta praevia
52
Risks of placenta accreta
Post-partum haemorrhage
53
Placenta Abruption
When the blood vessels adhering the placenta to the uterine wall rupture, leading to separation of the placenta from the uterus
54
Risk factors for placenta abruption
```
Smoking
Maternal hypertension (pre-eclampsia)
```
55
Signs and symptoms of placenta abruption
Abdominal pain
| Ante-partum bleeding
56
Placenta abruption: epidemiology
Occurs in 1% of pregnancies worldwide
57
In placenta abruption, what happens to the baby <30 weeks?
Monitor vitals until baby is old enough to deliver safely
Foetal lungs matured with corticosteroids
58
In placenta abruption, what happens to the baby >30 weeks?
Delivery
59
Twins: definition
Siblings that result from same pregnancy
60
Monozygotic twins
Identical twins with same genetic information
Originate from a single fertilised ovum
One egg, one sperm
The zygote splits into two embryos but share same placenta
61
Dizygotic twins
Non-identical
Release of two ova with both being fertilised and implanted independently
Two eggs, two sperm
Two different placentas
(So like two separate pregnancies in one)
62
Fallopian tubes
These extend laterally from the uterus to the ovaries
Provide a route for sperm to meet the ova - and for the ova to reach the uterus
63
What are fimbriae?
Finger-like projections that surround the ovary and sweep the ova into the fallopian tubes
64
How does the fallopian tube move the ova from the ovary to the uterus?
1. Tubes are lined with ciliated columnar epithelium that help move the ova towards the uterus
2. Smooth muscle layer performs peristalsis to assist in ova movement
65
Ovaries
The female gonads
Paired glands
Resemble size and shape of almonds
Atrophy after menopause
66
What is the ovarian ligament?
This anchors the ovaries to the uterus
67
Which hormones do the ovaries secrete?
Oestrogen
| Progesterone
68
Oogenesis
The formation of an egg (female gamete) in the ovaries
69
Where does oogenesis begin?
In the foetus
70
Primary oocytes
Formed by germ cells during foetal development
Stops at birth
Surrounded by a layer of follicular cells
71
Primordial follicle
A group of primary oocytes surrounded by a layer of follicular cells
72
How many follicles will mature and ovulate during a woman's reproductive lifetime?
Around 400
73
Which hormones are involved in oogenesis post-puberty?
Follicle stimulating hormone
| Luteinising hormone
74
What happens in oogenesis post-puberty?
FSH and LH are released by the anterior pituitary gland
FSH stimulates the maturation of the primordial follicles into a secondary oocyte
LH triggers ovulation - the release of the secondary oocyte
75
Primordial follicle maturation process
Primordial follicle > primary follicle > secondary follicle > mature follicle
76
Corpus luteum
The remains of the ovarian follicle once the secondary oocyte has been released
This produces progesterone and some oestrogen
Human chorionic gonadotrophin prevents the corpus luteum from degrading if secondary oocyte is fertilised
77
Corpus albicans
What the corpus luteum becomes if the secondary oocyte isn't fertilised
78
How long does the follicle maturation process take?
1 year
79
How long does the menstrual cycle generally last?
24-35 days
80
What is the average length of the menstrual cycle?
28 days
81
What are the four phases of the menstrual cycle?
1. Menstrual phase
2. Pre-ovulatory phase
3. Ovulation
4. Post-ovulatory phase
82
When does the menstrual phase happen?
Days 1-5
83
What happens during the menstrual phase?
Uterus: endometrium is shed in a response to progesterone lowering
Ovaries: follicles develop under the influence of FSH
84
When does the pre-ovulatory phase happen?
Days 6-13
85
What happens during the pre-ovulatory phase?
Uterus: endometrium thickens in response to rising oestrogen levels
Ovaries: one follicle starts to mature and inhibin is secreted which decreases the secretion of FSH (stops over follicles developing)
86
When does the ovulation phase happen?
Day 14
87
What happens during the ovulation phase?
Ovaries: high oestrogen levels create a positive feedback loop, stimulating LH secretion
LH causes rupture of the mature follicle and expulsion of the egg
88
When does the post-ovulatory phase happen?
Days 15-28
89
What happens during the post-ovulatory phase?
The corpus luteum forms from the follicle wall
It produces progesterone and some oestrogen to maintain the endometrium for pregnancy
90
Which hormones control the ovaries?
FSH
| LH
91
Which hormones control the uterus?
Oestrogen
| Progesterone
92
In what order do the hormones dominate during the menstrual cycle?
FSH
Oestrogen
LH
Progesterone
93
What happens to a fertilised egg (zygote)?
Zygote embeds in the uterine wall
Embryo produces human chorionic gonadotrophin (hCG) which maintains and stimulates the corpus luteum to produce progesterone and some oestrogen
After a few weeks the placenta takes over the role of producing hCG and progesterone to maintain the pregnancy
94
What happens to a non-fertilised egg?
After 14 days, the corpus luteum degenerates into the corpus albicans
Progesterone and oestrogen levels drop and a new menstrual cycle begins
95
What is puberty?
The period when the potential for sexual reproduction is reached
Internal reproductive organs mature and the first period happens (menarche)
96
When does puberty typically occur?
Between 10-14 years old
97
What happens as puberty starts?
The start of puberty is marked by pulses of LH and FSH, each triggered by a burst of GnRH
98
What happens as puberty advances?
The hormone pulses occur during the day as well as at night
These increase over 3-4 years
99
What are the secondary characteristics of puberty (females)?
Breast development
Hair growth (pubic/axillary/legs)
Hips widen
Voice deepens
100
What is the menopause?
Persistent cessation of menstruation for 12 consecutive months
101
At what age does menopause usually happen?
45-55 years old
102
What happens pathophysiologically when menopause occurs?
The number of follicles becomes exhausted
Oestrogen produced decreases
Decline in ovulation
Progesterone deceases
103
What affect does low oestrogen and progesterone have on other hormones?
FSH and LH levels increase
104
Which procedure can induce the menopause?
Hysterectomy
105
Menopause: signs and symptoms
```
Hot flushes and increased sweating
Mood changes, irritability, anxiety
Increased risk of UTIs
Breast shrinkage, sparse pubic/axillary hair
Osteoporosis
Deceased libido
Vaginal dryness
Painful intercourse
```
106
Menopause: allopathic treatment
HRT
107
How can HRT help during the menopause?
It can be used to relieve menopausal symptoms
Reduce risk of osteoporosis
But it only delays the actual menopause
108
What risks does taking HRT bring?
Breast and endometrial cancer
DVT
Stroke
Heart disease
109
What does the male reproductive system consist of?
```
Two of the following:
Testes
Epididymides
Vas deferens
Spermatic cords
Seminal vesicles
Ejaculatory ducts
```
One of the following:
Prostate gland
Penis
110
What does the penis consist of?
Root (within pelvic cavity)
| Body
111
What does the penis body consist of?
```
Three cylindrical masses of erectile tissue
Glans penis (the enlarged ending)
```
112
When does the penis fill with blood?
During sexual arousal
| During REM sleep
113
Which nervous system are the erectile tissue and involuntary muscle stimulated by?
Parasympathetic
114
Which substance causes vasodilation of the penis?
Nitric oxide
115
Where do the testes develop?
In the pelvic cavity (near kidneys)
They descend into the scrotum via the inguinal canals between around 2 months before birth
116
What are seminiferous tubules?
Area in the testes that produce sperm
117
How long does it take to produce sperm?
Around 70 days
118
Which hormone is involved in sperm production?
FSH
119
What is the role of the testes?
1. Produce sperm
| 2. Produce and secrete testosterone
120
Which hormone is involved in testosterone production?
LH
121
From which substance is testosterone made?
Cholesterol
122
Where in the testes is testosterone made?
Leydig cells
123
What are lobules?
Areas in the testes that contain the seminiferous tubules
124
How many lobules are there per testicle?
200-300
125
What is the epididymis?
Area in the testes where mature sperm is stored
126
How does sperm get from the seminiferous tubules to the epididymis?
Through muscle contraction
127
How many sperm are produced each day?
300 million
128
How long can sperm live for in the epididymis?
Several months
129
How many sperm are ejaculated?
Around 100 million per ml
130
What temperature is best for the production of sperm?
3 degrees C below body temperature
131
Sperm: anatomy
Head
Acrosome
Body
Tail
132
What does the head of the sperm contain?
Nucleus
133
What is the acrosome?
Vesicle covering the head of the sperm
| Contains enzymes to penetrate the egg
134
What is the body of the sperm filled with?
Mitochondria to fuel the tail
135
What is the function of the sperm tail?
To help it swim
136
What happens to sperm after it leaves the epididymis?
It's expelled through the vas deferens into the ejaculatory duct
137
What happens to sperm in the ejaculatory duct?
Semen is secreted and mixed with the sperm
138
Which glands produce semen?
Seminal vesicles
| Prostate gland
139
What are the seminal vesicles?
Pair of glands located behind the bladder
| They produce an alkaline fluid that makes up 60% of semen
140
What does the semen produced by the seminal vesicles contain?
Nutrients (e.g. fructose) to nourish sperm
141
What is the prostate gland?
Wraps around the male urethra
| Secretes a thin, milky fluid that makes up 30% of semen
142
What does the semen produced by the prostate gland contain?
Nutrients for ATP production
| Anticoagulants to increase fluidity
143
Which anticoagulants are included in the semen secreted by the prostate gland?
Citric acid
Proteolytic enzymes
Prostate specific antigen (PSA)
Pepsinogen
144
What is semen?
Alkaline fluid that protects sperm from urethral and vaginal acidity
145
What is the vas deferens?
Duct that transports sperm from the testicle to the urethra
146
What are the Cowper's Glands?
They secrete an alkaline, mucous fluid that neutralises urinary acids in the urethra prior to ejaculation
Also lubricate the end of the penis
147
What happens during sexual arousal?
Smooth muscle in the epididymis and vas deferens propel sperm into the ejaculatory ducts
Muscles surrounding the base of the urethra cause semen to eject out of the penis during orgasm
148
Considerations when taking case history
Menstruation - cycle/bleeding time/amount of blood/quality
Breasts - tenderness, galactorrhoea
Relationship of symptoms to cycle
Hirsutism (male hair pattern growth) and acne
Altered libido and impotence
Problems with intercourse
Past and present fertility plans
Methods of contraception
Operations
Additional symptoms e.g. urinary problems
Family history
149
Menarche
The age of the first period
150
Metrorrhagia
Mid-cycle bleeding
151
Menorrhagia
Increased menstrual bleeding
152
Amenorrhoea
Absence of periods
153
Dysmenorrhoea
Painful periods
154
Polymenorrhea
Short cycle, frequent periods
155
Oligomenorrhea
Infrequent cycles
156
Galactorrhoea
Lactation without pregnancy
157
Dyspareunia
Pain on intercourse (f)
158
Gynaecomastia
Presence of enlarged breast tissue in a male
