Reproduction Flashcards
(92 cards)
1
Q
Phases of the cell cycle
A
G1 (Gap 1) , S, G2 (Gap 2), M
2
Q
Which phases make up interphase
A
G1, S, G2
3
Q
G0 phase
A
- Non-dividing state that some cells enter from the G1 phase
- The cell is metabolically active but not preparing to divide
4
Q
G1 phase
A
Cell grows, carries out normal functions
5
Q
S phase
A
DNA is replicated (Each chromosome is duplicated)
6
Q
G2 phase
A
Cell prepares for mitosis, producing proteins and organelles
7
Q
Mitosis phase
A
includes mitosis and cytokinesis
8
Q
phases of mitosis
A
Prophase
Prometaphase
Metaphase
Metaphase
Anaphase
Telophase
9
Q
Prophase of mitosis
A
- Chromatin condenses into visible chromosomes
- Nuclear envelope begins to break down
- Spindle fibers begin to form
10
Q
Prometaphase of mitosis
A
- Nuclear envelope fully dissolves
- Spindle fibers attach to chromosomes at their centromeres
11
Q
Metaphase of mitosis
A
Chromosomes line up in the middle of the cell
12
Q
Anaphase
A
Sister chromatids are pulled apart to opposite poles of the cell
13
Q
Telophase
A
- Chromosomes decondense
- Nuclear envelopes re-form around each set of chromosomes
14
Q
Cytokinesis
A
- Cytoplasm divides, creating 2 identical daughter cells
15
Q
Cell checkpoints
A
G1 checkpoint
G2 checkpoint
Mitosis checkpoint
16
Q
G1 checkpoint
A
- End of G1 phase
- Checks for cell size, nutrients, growth factors, and DNA damage
- If the cell passes, it enters S phase; if it doesn’t, then it enters G0 for repair or apoptosis
17
Q
G2 checkpoint
A
- End of G2 phase
- Checks for proper DNA replication and DNA damage
- Cell may pass to Mitosis if not, cell pause to repair or self-destruct
18
Q
Mitosis Checkpoint
A
- During metaphase of mitosis
- Checks for proper attachment of spindle fibers to all chromosomes
- Ensures each sister chromatid will be pulled to opposite sides.
19
Q
Control of the cell cycle
A
Cyclins - activate CDKS
CDKS - enzymes that are only active when bound to a cyclin. Once activated, they phosphorylate target proteins to push the cell through a specific stage
20
Q
Meiosis
A
- Cell division that produces 4 non-identical haploid cells
- Essential for sexual reproduction
- 2 divisions ( Meiosis 1 - Separates homologous chromosomes) (Meiosis 2 - Separates sister chromatids)
21
Q
Prophase 1 of Meiosis
A
- Most complex and longest
- Synapsis - Homologous chromosomes pair up
- Crossing over - Exchange of DNA between non-sister chromatids
- Tetrads form
22
Q
Metaphase 1 Meiosis
A
- Tetrads align in the middle
- Independent assortment - Random orientation of maternal/paternal chromosomes
23
Q
Anaphase 1 Meiosis
A
- Homologous chromosomes are pulled apart to opposite poles
- Sister chromatids remain together
24
Q
Telophase 1 and Cytokinesis Meiosis
A
Two haploid cells form
25
Prophase 2 Meiosis
New spindle forms in each haploid cell
26
Metaphase 2 Meiosis
Chromosomes line up along the center
27
Anaphase 2 Meiosis
Sister chromatids finally separate
28
Telophase 2 and Cytokinesis
- Nuclear membranes reform
- 4 haploid gametes are produced
29
Mitosis vs Meiosis
- Synapsis and crossing over
- Alignment of homologous pairs at the metaphase plate
- Seperation of homologs
30
What is the primary sex organ for males ?
Testes
31
Testes
Produce sperm (through spermatogenesis) and testosterone
32
Inside the testes
- Seminiferous tubules
- Steroli Cells
- Leydig (Interstitial) cells
33
Seminiferous tubules
Where the sperm is produced
34
Sertoli cells
- Nourish developing sperm
- Respond to FSH
35
Leydig (Interstitial) Cells
- Produce testosterone
- Respond to LH
36
Sperm Pathway
SEVE UP
- Seminiferous tubules
- Epididymis
- Vas deferens
- Ejaculatory duct
- Urethra
- Penis
37
Seminiferous tubules
Sperm Production
38
Epididymis
Sperm mature and gain motility
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Vas deferens
Transports sperm during ejaculation
40
Ejaculatory duct
Fusion of vas deferens + seminal vesicle duct
41
Urethra
Carries Semen ( and Urine) through penis
42
Penis
Organ for delivering semen
43
Glands that produce seminal fluid
- Seminal vesicles
- Prostate gland
- Bulbourethral (Cowper's) glands
44
Seminal vesicles
Secretes fructose (energy for sperm), alkaline fluid, prostaglandins
45
Prostate Gland
secretes Alkaline fluid (Neutralizes vaginal acidity)
46
Bulbourethral (Cowper's) glands
Clear mucus that lubricates and neutralizes urethra
47
Hormonal control in males
- GnRH
- FSH
-LH
-Testosterone
48
GnRH
- Comes from the hypothalamus
- Targets the anterior pituitary
- Stimulates the release of FSH and LH
49
FSH
- Comes from the Anterior pituitary
- Targets Sertoli cells
- Promotes Spermatogenesis
50
LH
- Comes from the anterior pituitary
- Targets Leydig cells
- Stimulates testosterone production
51
Testosterone
- Comes from the testes
- Targets multiple tissues
- Promotes male secondary sex traits, spermatogenesis
52
Feedback regulation through testosterone
Negative feedback, testosterone inhibits GnRH, LH, and FSH release.
53
Spermatogenesis
The process of making sperm
54
Where does spermatogenesis occur ?
Seminiferous tubules of the testes
55
Process of Spermatogenesis
-Spermatogonia
-Primary spermatocytes
- Secondary spermatocytes
- Spermatids
- Spermatozoa (sperm)
56
Spermatogonia
- Diploid
- Stem cells; undergo mitosis
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Primary spermatocytes
- Diploid
- Enter Meiosis 1
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Secondary Spermatocytes
- Haploid
- After meiosis 1
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Spermatids
- Haploid
- After meiosis 2
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Spermatozoa
- Haploid
- Mature sperm; gain flagella in epididymis
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Spermatozoa Anatomy
- Head
- Acrosome
- Midpiece
- Tail
62
Head of sperm cell
- Contains nucleus : tightly packed haploid DNA
- Covered by the acrosome
63
Acrosome of the sperm cell
- Cap-like vesicle derived from the golgi apparatus
- Digestive enzymes to breach egg's outer coat
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Midpiece of sperm cell (Neck)
- Packed with mitochondria
- Provides ATP power flagellum (tail) for motility
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Tail (Flagellum) of the sperm cell
- Made of microtubules
- Propels the sperm using motion
- Flagella use dynein and ATP for movement
- ATP from mitochondria drives dynein motors on microtubules. This causes tail to beat
66
Ovaries
- Produce eggs (Through oogenesis)
- Secrete estrogen and progesterone
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Fallopian tubes
- Site of fertilization
- Transport egg to uterus
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Uterus
Muscular organ where implantation and fetal development occur
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Endometrium
- Inner uterine lining
- Thickens in response to estrogen and progesterone
- Sheds during menstruation
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Cervix
-Narrow opening between uterus and vagina
- Produces mucus that changes throughout cycle
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Vagina
Muscular canal for intercourse, menstrual flow, and birth canal
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Hormones in the female reproductive system
- GnRH
- FSH
- LH
- Estrogen
- Progesterone
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GnRH in females
- Comes from the hypothalamus
- Stimulates FSH and LH
74
FSH in females
- Come from the anterior pituitary
- Stimulates follicle development
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LH
- Comes from the anterior pituitary
- Triggers ovulation and corpus luteum formation
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Estrogen
- Comes from the ovarian follicles
- Builds endometrium ; promotes secondary sex traits
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Progesterone
- Comes from the corpus luteum
- Maintains endometrium for possible pregnancy
78
Egg path
OFUVC
Ovary
Fallopian Tube
Uterus
Vagina Cervix
79
Where does Oogenesis occur ?
In ovaries
80
What are the key stages of Oogenesis ?
Oogonium
Primary oocyte
Secondary oocyte + 1 polar body
Ovum + 2nd polar body
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Oogonium
- Diploid
- Stem cell undergoes mitosis before birth
82
Primary oocyte
- Diploid
- Arrested in prophase 1 from birth until ovulation
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Secondary oocyte +1 polar body
- Haploid
- After meiosis 1
- Completed at ovulation
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Ovum + 2nd polar body
- Haploid
- Only completed if fertilization occurs (Meiosis 2 ends)
85
Timeline of Oogenesis
Fetal development: All oogonia → primary oocytes → arrested in prophase I
Puberty (menarche): Each menstrual cycle, one primary oocyte completes meiosis I → forms secondary oocyte
Ovulation: Secondary oocyte is released and arrested in metaphase II
Fertilization: Triggers completion of meiosis II
86
The menstrual cycle
- Length 28 days
- 4 phases - Follicular phase, Ovulation, Luteal phase, Menstruation
87
Follicular phase
- Days 1-13
- Triggered by low estrogen and progesterone
- Increase GnRH, FSH, and LH
- FSH stimulates follicle growth; Follicles secrete estrogen
- Several follicles begin maturing, only one becomes dominant
- Endometrium rebuilds under influence of estrogen
88
Ovulation phase
- Day 14
- Triggered by estrogen surge; LH surge
- Rupture of the Graafian follicle > Releases secondary oocyte
- Endometrium continues to thicken in preparation for implantation
- LH surge = ovulation trigger
- Secondary oocyte is arrested in metaphase 2
89
Luteal Phase
- Days 15-28
- LH > Stimulates corpus luteum formation > secretes progesterone and some estrogen
- Endometrium is maintained
90
Menstruation phase
- Day 1
- Triggered by the drop in progesterone/estrogen (Corpus luteum degenerates)
- Shedding of the endometrial lining
- Low hormones ; GnRH rises ; Cycle restarts
91
Estrogen negative feedback
- In the early follicular phase (Days 1-7), estrogen is rising
- Estrogen exerts a negative feedback decrease in GnRH from the hypothalamus and FSH/LH from anterior pituitary
- Prevents excess follicle development
92
Estrogen positive feedback
- Estrogen levels peak
- GnRH and LH surge
- Trigger ovulation through LH surge
