FINAL EXAM Flashcards
1
Q
Gonads (male)
A
testes
2
Q
Gonads (female)
A
ovaries
3
Q
The ____ produce sex cells
A
gonads
4
Q
At puberty: the secretion rates of the hormones from the…
A
gonads increased markedly. This is the period of active reproduction
5
Q
What are the hormones drive the testes?
A
Hypothalamus drives GnRH, then secretes Lh/FSH, then secretes testosterone
6
Q
Male Reproductive Function: Essential reproductive functions (2)
A
- production of sperm
- delivery of sperm to the female tract
7
Q
Sperm production aka
A
spermatogenesis
8
Q
Spermatogenesis occurs in
A
the testes
9
Q
Testes are housed in
A
the scrotum which provides cooler environment for sperm development
10
Q
Accessory sex glands provide…
A
secretions (semen) in which the sperm are transported
11
Q
Puberty (2) male
A
- Nocturnal sleep-related increase in pulsatile LH secretion stimulated by an increase in pulsatile GnRH
- Sensitivity of the hypothalamus and pituitary to negative feedback is reduced (maturation of the CNS)
12
Q
The time of onset of puberty includes a
A
heritability factor
13
Q
Affected by sensory inputs such as (6)
A
- growth
- body fat/composition (leptin)
- diet
- stress
- gonadal steroids
- endocrine disruptors
14
Q
Puberty (Appearance of the Secondary Sexual Characteristics) male
A
- pubic and axillary hair
- facial hair
- thickening of skin
- growth spurt
- increase in skeletal muscle mass
15
Q
Production of testosterone by the…
A
Leydig cells (interstitial cells) - stimulated by LH
16
Q
Testosterone is a
A
steroid hormone (derived from cholesterol)
17
Q
Testosterone binds to its
A
intracellular receptor and leads to transcription of genes
18
Q
Functions of Testosterone (5)
A
- Effects on the reproductive system before birth
- Effects on sex-specific tissues after birth
- Effects on the brain
- Effects on secondary sexual characteristics
- Nonreproductive actions
19
Q
Effects on the reproductive system before birth (Test)
A
- masculinization of the reproductive tract and external genitalia
- promotes descent of tests into scrotum
20
Q
Effects on sex-specific tissues after birth (test)
A
- growth and maturation of the reproductive system at puberty
- spermatogenesis
- maintains male reproductive tract in adulthood
21
Q
Effects on the brain (test)
A
- sex drive (libido)
- controls gonadotropin (LH and FSH) secretion
22
Q
Effects on secondary sexual characteristics (test)
A
- male pattern of hair growth (e.g. facial hair)
- deepening of voice
- muscle growth - male physique
23
Q
Nonreproductive functions (test)
A
- protein anabolic effect
- bone growth at puberty
- closure of epiphyseal plates (conversion to estrogen)
- aggressive behavior (conversion to estrogen)
24
Q
Testosterone has three fates…
A
- Testosterone, bone, muscle growth
- Conversion to dihydrotestosterone (DHT)
- conversion to estrogen
25
DHT (2) (testo)
1. responsible for secondary sex characteristics in males
2. effects on the accessory sex organs
26
Estrogen (3) (testo)
1. usually occurs in the brain
2. responsible for libido
3. aggressive behavior
27
Spermatogenesis (location)
takes place in the seminiferous tubules which make up 80% of testicular volume
28
Sperm mature and are stored in
the epididymides until ejaculation
29
Within the seminiferous tubules sustentacular cells (sertoli cells)
support the developing sperm
30
Spermatogenesis is stimulated by ___&____
FSH and testosterone
31
FSH and testosterone have a direct effect on
Sertoli cells which then support spermatogenesis
32
Spermatogenesis is the
process of sperm formation
33
Spermatogonia are the...
stem cells used to generate mature sperm and continue to divide to produce more spermatogonia
34
Type A Spermatogonia
maintain the germ line
35
Type B Spermatogonia
pushed toward the lumen and become primary spermatocytes
36
Prior to puberty spermatogonia
only divide by mitosis
37
Spermatogenesis (Stage 1)
forming spermatocytes
- type be spermatogonia become primary spermatocytes
38
Spermatogenesis (Stage 2)
Meiosis
- meiosis I: each primary spermatocyte forms 2 smaller haploid cells (secondary spermatocytes)
- meiosis II: formation of small round spermatids
39
Spermatogenesis (Stage 3)
spermiogenesis
- spermatids elongate, shed excess cytoplasm and form a tail
- result: spermatozoan (sperm)
40
Primary spermatocyte =
2n
41
Secondary spermatocyte =
n, haploid
42
Main Steps of Spermatogenesis
1. Mitosis (cell division)
- production of primary spermatocyte (2n)
2. Meiosis I
- production of secondary spermatocyte (n, haploid)
3. Meiosis II
- production of spermatids (n, haploid)
43
Spermatogenesis takes how long
65-75 days
44
Overall result (spermatogenesis)
23 pairs of homologous chromosomes is reduced to a set of 23 chromosomes per sperm
45
Sertoli cells are bound to each other by tight junctions, forming the blood testis barrier. What is the role of Sertoli cells?
prevents membrane antigens of the differentiating sperm from escaping through the basal lamina and into the bloodstream - preventing immune reactions
46
Summary: Control of Testicular Function (3) its a lot
1. GnRH indirectly stimulates the testes through its effects on LH and FSH release
2. The gonadotropins (FSH and LH) directly stimulate the testes
3. Gonadal hormones (testosterone and inhibin) regulate secretion of the hypothalamus (GnRH) and anterior pituitary (LH, FSH)
47
Female Reproductive Functions (4)
1. production of ova (oogenesis)
2. transport of sperm and ovum to common site for union (fertilization or conception)
3. maintenance of developing fetus
4. giving birth (parturition)
48
The ovaries functions (3)
1. produce ova
2. secrete reproductive hormones (estrogen&progesterone)
3. The production of ovarian hormones is under the control of the anterior pituitary gland
49
Oogenesis means
beginning of an egg
50
Oogenesis (fetal period) (3)
1. Diploid stem cells (oogonia) multiply by mitosis
2. oogonia are transformed into primary oocytes surrounded by 1 layer of follicular cells (primary follicles)
3. primary oocytes begin meiosis I but are arrested in prophase I
51
Oogenesis (after birth) (2)
1. Start with approx. 2 million primary oocytes
2. quiescence in the ovary
52
Oogenesis (at puberty) (3)
1. recruitment of oocytes each month
2. only 1 or 2 selected oocytes will be released and continue meiosis I, producing the first polar body and the secondary oocyte (each haploid, 23 chromosomes)
3. secondary oocyte is arrested in meiosis II (until fertilization)
53
End products of Oogenesis
1. three tiny polar bodies - lack cytoplasm and nutrients; they eventually die
2. one large ovum (functional)
54
End products of spermatogenesis
1. four viable gametes (spermatozoa)
55
Ovarian cycle (3)
1. monthly series of events associated with the maturation of the egg
2. average 28 day cycle; can vary from 21-40 days
3. ovulation (release of oocyte) occurs mid cycle, approx day 14
56
Phases of the ovarian cycle
follicular phase
luteal phase
57
Follicular phase (4)
1. days 1-14
2. characterized by the development of ovarian follicles
3. estrogen is the dominant (major) reproductive hormone
4. length determines the length of the cycle
58
Luteal phase (4)
1. post-ovulation
2. days 14-28
3. characterized by the presence of the corpus luteum
4. progesterone is the dominant reproductive hormone
59
Follicular phase process (4)
1. primordial follicle becomes a primary follicle
2. primary follicle becomes a secondary follicle
3. secondary follicle becomes a late secondary follicle
4. late secondary follicle becomes a Graafian (vesicular) follicle
60
FSH produced by the gonadotrope cells of the anterior pituitary stimulates...
the development of follicles in the ovaries and production of estrogen by the follicular cells
61
Follicles in the ovaries, mature, and release an...
oocyte (egg) in response to FSH and LH
62
Ovulation (def)
rupturing of the ovarian wall and expulsion of the secondary oocyte surrounded by the corona radiata
63
Ovulation (follicles)
1 follicle makes it to the Graafian (dominant) follicle stage, the others undergo atresia (die)
- dominant follicle has the most FSH receptors
64
Graafian follicle is the
dominant follicle will undergo ovulation
65
Pain is sometimes felt by women during..
ovulation (mittelschmerz)
66
Ovulation stimulated by the surge of
LH
67
Luteal phase (3)
- follows ovulation
- ruptured follicle collapses and antrum fills with clotted blood (corpus hemorrhagicum)
- corpus luteum "yellow body" forms
68
Corpus luteum
- starts to secrete progesterone and estrogen
- starts to deteriorate after approx. 10 days, leaving the corpus albicans, the "white body" in the last 2-3 days of the phase
69
Hormonal regulation of the ovarian cycle
1. GnRH is responsible for release of FSH and LH
2. Pituitary gonadotropins stimulate the ovarian follicular cells to secrete estrogen/progesterone
3. onset of puberty in females is linked to adiposity (fat tissue)
4. menarche - first menstrual period (usually not ovulatory)
70
Uterine (Menstrual Cycle) (days)
Days 1-5: Menstrual phase
Days 6-14: Proliferative Phase
Days 15-28: Secretory Phase
71
Days 1-5 Menstrual phase
shedding of the endometrium (stratum functionalis) along with bleeding
72
Endometrium
functional layer
- stratum functionalis
73
Days 6-14 Proliferative Phase
- endometrium is rebuilt, new function layer is generated (due to estrogen)
- increase in # of progesterone receptors
- estrogen causes the cervical mucus to become thin and watery (allow passage of sperm)
74
Days 15-28 Secretory Phase (4)
- endometrial glands secrete glycogen into the uterine cavity
- if pregnancy does not occur, CL regresses and estrogen/progesterone lvls drop cause the shedding of the functional layer, cycle starts again
75
Ovarian hormones
- estrogen
- progesterone
76
Estrogen produced by
- ovarian follicles
- corpus luteum
77
Estrogen effects
- inhibits osteoclasts, deficiency leads to osteoporosis
- proliferation of the uterine endometrium
- secondary sex characteristics
- produces ductal growth in the breast
78
Progesterone produced by
corpus luteum
79
Progesterone effects
- responsible for the secretory phase in the uterus
- increases growth of lobules in the breast
- increases metabolic rate
80
Estrogen and Secondary Sex characteristics
- growth and development of the breasts
- increased deposition of subcutaneous fat, especially in the hips and breasts
- widening of and lightening of the pelvis (facilitate childbirth)
81
Menopause
- cessation of ovarian acitivty and menstruation
- age around 50 years
- estrogen withdrawal causes hot flashes, and atrophy of the vaginal wall and eventually osteoporsis
82
The Estrous Cycle is approx...
21 days long
83
Ovulation occurs at the end of
the follicular phase - coincident with estrus
84
At least __waves of follicles develop during the follicular phase
3
85
After ovulation...
the remaining follicular cells become the corpus luteum (CL)
86
The CL secretes...
progesterone which is needed to establish pregnancy
87
At approx day 17 of the estrous cycle...
the uterus secretes PGF2alpha, which causes the demise of the CL
88
Ovulation happens between
the follicular phase and luteal phase
89
Estrus is part of the end of the
follicular phase
90
During estrus, estrogen levels are
high
91
High estrogen causes
high LH
92
LH peaks before
ovulation
93
FSH is higher during the
follicular phase
94
Fertilization (3)
- fusion of sperm and egg to form the zygote
- sperm viable for up to 5 days after ejaculation
- egg viable for only 12-24 hours after ovulation
95
Journey to egg takes 1-2 hours and only...
ONE sperm eventually fertilizes the egg
96
To achieve fertilization...
coitus must occur no more than three days before ovulation or 24 hrs after ovulation
97
Sperm Transport: fates of ejaculated sperm
1. leak out of vagina immediately after deposition
2. Destroyed by the acidic vaginal environment
3. fail to make it through the cervix
4. dispersed in the uterine cavity or destroyed by phagocytic leukocytes
5. Reach the uterine tubes
98
Sperm must undergo ___ before they can penetrate the oocyte
capacitation
99
Capacitation
- enhanced motility, removal of some membrane proteins to make their membrane less fragile to prepare or fertilization
- process takes 8-10 hrs
100
Spermatozoa must reside in the...
female tract before they acquire maximum fertility
101
Spermatozoa and Capacitation (3)
1. The plasma membrane of epididymal spermatozoa contains complement surface molecules
2. Seminal plasma cots the membrane molecules
3. Female tract environment removes the coatings exposing portions of the molecules that can bind with zona pellucida
102
An ovulated oocyte is encapsulated by:
- the corona radiata
- the zona pellucida
103
Sperm binds to____ and undergoes the acrosomal reaction
zona pellucida
104
Acrosomal reaction
- enzymes are released near the oocyte
- hundreds of acrosomes release their enzymes to digest the zona pellucida
105
Blocks to Polyspermy
- only one sperm is allowed to pentrate the oocyte
- two mechanisms ensure monospermy
106
Polyspermy Mech (2)
1. fast block to polyspermy: membrane depolarization prevents sperm from fusing with the oocyte membrane
2. Slow block to polyspermy
107
Slow Block to polyspermy
- the cortisol granules release enzymes that destroy sperm receptors (cortical rxn)
- these enzymes cause sperm already bound to receptors to detach
