41 Human Reproduction Flashcards
1
Q
What is a Gonad
A
An organ that produces sex cells in animals
2
Q
Why is the temperature in the scrotum maintained at 35°
A
So meiosis can occur, producing sperm
3
Q
What are the male gonads called
A
The testes
4
Q
When do testes develop in a male
A
A few weeks before birth they descend out of the body caviity into a pouch called the scrotum
5
Q
What does each testis consist of
A
Coiled mass of tubules (50cm)
6
Q
What cells are tubules lined with and what occurs there
A
Diploid sperm producing cells, meiosis occurs in these cells to produce haploid sperm
7
Q
What do cells located between the tubules produce
A
Testosterone
8
Q
Where is the epididymis located
A
outside each testis
9
Q
What happens in the epididymis
A
Sperm mature and are stored for up to 6 weeks
10
Q
What happens to sperm in the epididymis if they ate not released
A
They are broken down and taken back into the bloodstream (resorption)
11
Q
What is resorption in males
A
When sperm isn’t released from the epididymis and is broken down and taken back into the bloodstream
12
Q
What do the sperm ducts do
A
They carry sperm to the urethra
13
Q
Where is the male urethra located
A
in the centre of the penis
14
Q
What is the function of the male urethra
A
Dual function of carrying urine or sperm out of the body at different times
15
Q
What is semen
A
A fluid containing sperm and seminal fluid
16
Q
What does seminal fluid provide for sperm
A
A medium for the sperm to swim in and nourishment as it contains fructose
17
Q
What glands produce seminal fluid
A
Seminal vesicles
Prostate gland
Cowper’s glands
18
Q
How many chromosomes in a sperm cell
A
23 as they are haploid
19
Q
What do sperm producing cells divide by to produce sperm cells
A
Meiosis
20
Q
WHAT DOES each sperm cell contain
A
Acrosome (Region containing enzymes that can digest the membrane of an egg)
Nucleus (containing 23 chromosomes)
Midpiece (containing mitochondria)
Tail (so it can swim)
21
Q
When are sperm cells first produced
A
At the onset of puberty (sexual maturity), about 12 or 13yrs
22
Q
Define Puberty
A
The beginning of sexual maturity
23
Q
What is the glans in male reproductive system
A
The swollen tip of the penis
24
Q
What does the foreskin partially cover
A
It partially covers the glans (swollen tip of penis)
25
What is the penis
Structure adapted to introduce sperm into the female reproductive system
26
Why does the penis become erect during sexual arousal
More blood flows into the penis than can flow out of it
27
In what state can the penis be used to place sperm into the female system
When it is erect
28
What two hormones are produced by the male pituitary gland at puberty
FSH (Follicle stimulating hormone)
LH (Luteinising hormone)
29
What does LH do in male reproductive sustem
The luteinising hormone
**stimulates** the **testes** to **produce testosterone**
30
What does FSH do in male reproductive sustem
**Causes** the **diploid sperm producing cells** to **divide** by **meiosis** and **produce** haploid **sperm**
31
What are androgens
Male hormones
32
What is the main androgen
Testosterone
33
When does the production of testosterone increase enormously
At puberty
34
What does the enormous increase of testosterone production cause
Enlargement of penis, testes and other reproductive parts
Causes the secondary male characteristics
35
When and where is testosterone produced in small amounts
By testes before puberty in males
By the female ovaries throughout life
36
What are Secondary Sexual Characteristics
are those features that distinguish males from females, apart from the sex organs themselves.
37
Name 4 Secondary make characteristics
Growth of pubic, underarm,facial,body hair
Enlargment of larynx causing voice to break and deepen
Increased muscular and bone development
Widening of shoulders
Growth spurt
Increased secretion of sebum in skin
38
Define infertility
Inability to produce offspring
39
Whats the main type of male infertility
The production of low numbers of sperm
40
What are some causes of low sperm count
Persistent smoking of cigarettes
Alcohol abuse
Marijuana use
Anabolic steroid use
Low level of male hormones
Mumps in adult life
Contact with certain chemicals in detergents and plastics
41
What are some corrective measures of low sperm count
Changes in diet and lifestyle:
Stopping smoking
Not taking drugs
Stopping/reducing alcohol consumption
Reducing stress levels
If cause is hormonal then hormone supplements may be administered
In-vitro fertilisation
42
If the cause of low sperm count is hormonal, what corrective measures may be taken
Administration of hormone supplements
43
Define ovulation
Release of an egg from the ovary
44
What do the ovaries produce
Female hormones
Eggs
45
How many potential eggs may the ovaries contain at birth
Up to 1million potential (diploid) eggs
46
What age does puberty occur in females
About 11 or 12
47
What has the no. of potential eggs fallen to at puberty
40 thousand
48
What is each potential egg enclosed in
A cluster of cells forming a follicle in the ovary
49
After puberty how many eggs are produced by meiosis each month
About 20. Usually only one continues to grow, rest die off
50
What is an ovum
A haploid egg (23 chromosomes)
51
What does a Graafian Follicle produce
The female hormone Oestrogen
52
When is an egg surrounded by a Graafian Follicle
Once meiosis is complete the haploid egg is surrounded by a Graafian Follicle
53
What happens as the Graafian Follicle matures
It forms a swelling on the surface of the ovary, it bursts at ovulation to release the egg
54
After ovulation, what happens to the follicle
It fills with yellow cells becoming the corpus luteum which secretes the hormone progesterone
55
What hormone does the corpus luteum secrete
Progesterone
56
What is the Oviduct
a collective term for the Fallopian tubes and the funnel
57
What do the ends of fallopian tubes have to catch the egg after ovulation
Funnels
58
How is the egg moved along the fallopian tube
By cilia and muscular peristalsis
59
What are the 2 events that can happen to the egg in the fallopian tube
Either fertilised or dies
60
What is the uterus
A muscular structure about the size of a fist
61
What is the uterus made of
Outerwall- involuntary muscle
Inner lining=Endometrium
62
What happens to the inner lining of the uterus (endometrium) each month
It thickens with cells and blood vessels to nourish the embryo in event of pregnancy
63
What is the opening into the uterus called
Cervix
64
What is the vagina
An elastic muscular tube abt 10cm long that allows entry of sperm and acts as birth canal
65
What is the vagina lined with
Mucous producing cells
66
Where does the female urethra open
Near the vagina
67
What are the labia
folds of skin that protect the vagina
68
What is the vulva
Labia Vagina and Urethra collectively
69
What is the hymen
Ring of tissue that may partially block the vagina entrance
Stretched or torn by tampons or first sexual intercourse
70
Define the menstrual cycle
Series of events that **occurs every 28 days** on average in the female **if fertilisation has not taken place**
71
Define menopause
When ovulation and menstruation stop happening in a female
72
When does the menstrual cycle begin for the first time and end
begins at puberty and continues until menopause (age 45-55)
73
What happens in days 1-5 of a menstrual cycle
Endometrium breaks down and is shed through vagina (menstruation)
Meiosis occurs in ovary to produce new egg
New egg surrounded by Graafian Folicle
74
What happens in days 6-14 of a menstrual cycle
the developing **Graafian Follicle produces Oestrogen** which causes **endometrium** to **thicken** again
**Oestrogen prevents new eggs developing** so only **one Graafian Follicle develops**
75
what happens on day 14 of the menstrual cycle
Ovulation occurs when Graafian Follicle bursts
Egg passes into abdomen, funnel, then moved along fallopian tube
Egg is available for fertilisation for up to 48 hrs
76
How long is the egg available for fertilisation after ovulation
Normally up to 48 hours
77
What happens from days 14-28 in a menstrual cycle
**Graafian Follicle** remains develop **into Corpus Luteum**, then **makes progesterone**, which **thickens endometrium** even mire
**Progestoren prevents new eggs** from forming, **egg** that was released **will die by day 16 if not fertilised**
**Corpus lutuem degenerates** around **day 22** if no fertilisation occurs.
**Reduction in progesterone** levels which causes **endometrium to break down on day 28**
On **day 28**, **endometrium released** through vagina (menstruation) lasts for 5 days
Marks start if new cycle
78
Functions of Oestrogen and Progesterone
Oestrogen- Endometrium thicken in first half of cycle
Progesterone- Continues this in second 14 days
Both prevent eggs from developing
79
Why are oestrogen and progesterone used in contraceptives
Those hormones both prevent eggs from developing
80
Name 5 female secondary sexual characteristics
Maturing+Enlargment of breasts
Widening of pelvis
Increased body fat
Growth of pubic and underarm hair
Growth spurt
81
Define menstruation
Menstruation is the discharge of the lining of the uterus (the endometrium)
and the unfertilised egg.
82
What is the most common female infertility
Failure to ovulate due to **endocrine gland failure**
83
What causes endocrine gland failure (female infertility)
Pituitary fails to produce FSH or LH
Lack of FSH= failure of eggs to form
Lack of LH=failure to ovulate
84
Corrective measures for Endocrine Gland Failure (female infertilitt)
hormone supplements by injection
In-Vitro fertilisation
85
What are the four hormones involved in the menstrual cycle
FSH (Follicle stimulating hormone)
Oestrogen
LH (Lutenising hormone)
Progesterone
86
FSH in the menstrual cycle
Produced un pituitary gland
Produced jn days 1-5
Stimulates a few potential eggs to develop, surrounded by Graafian Follicles
Graafian follicles then secrete oestrogen
87
Why is FSH used in fertility treatments for women
To stimulate the ovaries to produce eggs
88
Oestrogen in the menstrual cycle
Produced by Graafian Follicle (in ovary)
Produced from days 5-14
Causes endometrium to develop
Inhibits FSH
High levels of oestrogen just before day 15 stimulate release of LH
89
LH in the menstrual cycle
Produced by pituitary gland
produced on day 14
Causes ovulation, remains of Graafian Follicle to develop into Corpus Luteum
Which makes progesterone
90
Whats another name for Corpus luteum
The yellow body
91
Progesterone in the menstrual cycle
Produced by the corpus luteum
Produced from days 14-28
Maintains structure of endometrium
Inhibits production of FSH and LH
92
What happens when pregnancy doesnt occur and low levels of progesterone and oestrogen are present
FSH secretion by pituitary gland is no longer inhibited
As FSH level rises, new eggs develop
Uterus contracts and endometrium is shed from body causing menstruation
93
Name a menstrual disorder
Fibroids
94
What are fibroids
Benign tumours of uterus
result from Overproduction of cells
Slow growing. Pea->Grapefruit in size
Age 35-45
Can cause heavy prolonged period, miscarriage, infertility
95
What is. the cause of Fibroids (menstrual disorder)
Uncertain
May be an abnormal response to oestrogen, tend to be larger in women taking hormonal contraceptives
96
Whats the prevention and treatment of fibroids
Small fibroids= No treatment, regular examinations
Large fibroids=surgery, if theres a lot then hysterectomy
97
What are the three stages of copulation
Sexual arousal
Copulation
Orgasm
98
Define copulation
The act of sexual intercourse
99
Define orgasm
Orgasm is the physical and emotional sensations experienced at the peak of sexual excitement.
100
Define ejaculation
The release of semen from the penis
101
Defone insemination
The release of semen into the vagina, just outside the cervix
102
What happens to the penis in sexual arousal
blood flow into penis increases, blood flow out of penis decreases
Spongy tissue in penis fills with blood and ot becomes erect
103
What happes to the vagina in sexual arousal
Becomes lubricated elongated and wider
104
What happens to both partners during copulation
Breathing and heart rate increases
105
what happens to muscles in pelvis of both partners during orgasm
Contract and heart rates resporation and blood pressure rise dramatically
106
What happens to the female only during orgasm
Outer vagina and uterus contract
107
What happens to the male only during orgasm
Sphincter muscle from bladder closes and contraction of involuntary muscles in epididymis, sperm ducts, glands and urethra discharge semen out of penis
