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Reproduction And Development Flashcards

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1
Q

With exception to which hormones, all reproductive hormones are _ hormones released from the testes, ovaries, and placenta

A

Except for FSH, LH, HCG, and inhibin which are peptide hormones
All other reproductive hormones are steroid hormones

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2
Q

Gonads

A

Organs involved in the production of gametes

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3
Q

Male Gonads

A

Testes

Involved in the production of gametes, or spermatocytes

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4
Q

Seminiferous tubules

A

Organ in which the production of sperm occurs

Set of long twisted tubes in the testes that are lined by Sertoli cells and spermatogonia

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5
Q

Spermatogonia

A

Located in the seminiferous tubules and arise from epithelial tissue to become spermatocytes, spermatids, and spermatozoa

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6
Q

Sertoli Cells

A

Surround and nurture the spermatocyte and spermatids
Stimulated by follicle-stimulating hormone (FSH)
Secrete inhibin, a glycoprotein hormone that acts on pituitary gland and inhibits FSH secretion

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7
Q

Leydig Cells

A

Cells located in the interstitium between the seminiferous tubules
Release testosterone when stimulated by luteinizing hormone

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8
Q

Primary androgen

A

AKA male sex hormone
Testosterone
Stimulates the germ cells to differentiate into sperm
Responsible for development of secondary sex characteristics
Helps to initiate growth spurt and stimulates closure of epiphyses of long bones (ends growth in height)

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9
Q

Secondary Male Sex Characteristics

A

Pubic hair, enlargement of the larynx, growth of the penis and seminal vesicles

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10
Q

What is Spermatogonium and how does it mature?

A

Sperm stem cell before it undergoes meiosis
After entering meiosis, becomes spermatocyte
At end of meiosis, becomes spermatid
Spermatid loses cytoplasm and forms the head, mid-piece, and tail to become a spermatozoon (sperm)

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11
Q

Spermatozoon

A

AKA sperm
Matured male gamete with a head, mid-piece, and tail
Head: composed of nuclear material and an acrosome (contains lysosome-like enzymes for penetrating the egg during fertilization)
Midpiece: Contains many mitochondria to provide energy for movement of tail
Only nuclear portion of sperm enters the egg

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12
Q

Where does the spermatozoon mature?

A

Exits the seminiferous tubules and is carried to epididymis to mature
After ejaculation, spermatozoa are propelled through the vas deferens into the urethra and out of the penis

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13
Q

Semen

A

Complete mixture of spermatozoa and fluid that leaves the penis upon ejaculation
Composed of fluid from the seminal vesicles, prostate, and bulbourethral glands (Cowper’s glands)

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14
Q

Capacitation

A

Process that occurs in the vagina in which spermatozoa become activated for fertilization

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15
Q

When does the ovarian cycle begin?

A

Start of oogenesis begins at birth where all of the eggs are arrested as primary oocytes in prophase I of meiosis at birth

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16
Q

When does the ovarian cycle begin?

A

At puberty
Follicle stimulating hormone stimulates the growth of granulosa cells around the primary oocyte
Granulosa cells secrete a viscous substance around the egg called the zona pellucida and egg becomes primary follicle

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17
Q

How does the primary follicle become the secondary follicle?

A

Theca cells in the primary oocyte differentiate from the interstitial tissue and grow around the follicle to form a secondary follicle
Upon stimulation by luteinizing hormone, theca cells secrete androgen, which is converted to estradiol (type of estrogen) by granulosa cells in presence of FSH and secreted into the blood

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18
Q

Luteal Surge

A

Just before ovulation, estradiol level rises rapidly and causes a dramatic increase in luteinizing hormone secretion
Results from positive feedback from rising estrogen which increases LH levels, which increases estrogen
Causes ovulation, bursting of follicle, and release of the egg (secondary oocyte) into body cavity

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19
Q

What happens when the egg is released from the ovary?

A

Egg is swept into the fallopian (uterine) tube by the fimbriae
Remaining portion of the follicle is left behind to become the corpus luteum
Corpus luteum secretes estradiol and progesterone through pregnancy, or 2 weeks after if not pregnant until it degrades into the corpus albicans

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20
Q

What are the stages of oocyte development and ovulation?

A
  1. Primary oocyte within follicle
  2. Follicle is growing and consists of oocyte and zona pellucida surrounded by granulosa cells surrounded by theca cells
  3. Follicle grows into secondary (Graafian) follicle
  4. Ovulation: follicle ruptures, releases secondary oocyte, secondary oocyte with corona radiata
  5. Corpus luteum develops from remnants of follicles
  6. Corpus luteum degenerates to corpus albicans if no fertilization of egg
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21
Q

Ovarian Cycle

A
  1. Follicular Phase: Begins with development of follicle and ends with ovulation
    Includes Menstruation and Proliferation phase
  2. Luteal Phase: Begins with ovulation and ends with degeneration of corpus luteum into corpus albicans
    Includes Secretory Phase
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22
Q

When does the uterine cycle begin?

A

Day 0, also the first day of menstruation and the first day of the follicular phase

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23
Q

When does menstruation stop?

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A

As the follicle matures and begins to release more estradiol

Proliferation phase then begins

24
Q

Proliferation Phase

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A

Phase after menstruation in which the uterine wall is rebuilt (building phase)
Lasts until ovulation

25
What happens after ovulation?
Corpus luteum begins to secrete progesterone, acts as maintennace hormone for uterus Corpus luteum will degrade if no pregnancy into corpus albicans, no longer able to secrete progesterone to maintain uterine wall Uterine wall sloughing off begins menstruation
26
What hormones are involved in the ovarian cycle and how do they vary?
FSH is high at beginning of menstruation, slowly drops, and surges just before ovulation. FSH drops to low again, and starts to rise for start of menstruation LH is low at beginning of menstruation, surges just before ovulation and then drops to very low. Estrogen is low during menstruation, surges at end of proliferation, drops at ovulation, and rises during secretory phase Progesterone is low during menstruation, and slowly rises once ovulation starts, dropping near end of secretory phase
27
What happens as sperm makes contact with egg?
Enzymes digest a path for sperm through granulosa cells and zona pellucida Cell membranes of sperm head and oocyte fuse upon contact, sperm nucleus enters cytoplasm of oocyte causing the cortical reaction
28
What is the cortical reaction?
Cortical reaction happens when sperm enters cytoplasm of oocyte and prevents other sperm from fertilizing the same egg Second meiotic division of oocyte occurs and oocyte becomes ovum, releases second polar body
29
When does fertilization occur?
When the nuclei of the ovum and sperm fuse to form the zygote
30
Embryonic Cleavage
The stage that occurs after fertilization which involves repeated divisions of the zygote through the 2-cell, 4-cell, and 8-cell stage Occurs while the zygote is in the fallopian tube Zygote becomes morula when reaches 16 cells
31
Do the cells grow in size during cleavage?
Embryo does not grow during cleavage. First 8 cells are equivalent in size and shape Totipotent- potential to express any of their genes
32
Blastocyst
Mostly hollow ball filled with fluid, small cell mass on one side Formed after cells of morula continue to divide for four days Blastocyst implants in the uterine wall and fuses with uterine tissue to form placenta
33
Implantation
Process that occurs about seven days after fertilization Outer cells of blastocyst implants in uterine wall and fuse with uterine tissue to form placenta Small mass of cells on inside of blastocyst become embryo, made up of stem cells which are pluripotent- can develop into most types of cells in human body Marks the beginning of the pregnancy
34
What occurs after implantation?
Placenta begins secreting the peptide hormone human chorionic gonadotropin (HCG) Prevents degeneration of corpus luteum and maintains secretion of estrogen and progesterone HCG first sign of pregnancy
35
When does the placenta reach full development?
End of first trimester | Begins to secrete own estrogen and progesterone, lowers secretion of HCG
36
When do cells begin to differentiate?
At end of 8-cell stage due to cell-to-cell communication | Blastocyst: inner cells become embryo, outer cells become placenta
37
Determination
Cell becomes committed to a specialized developmental path | Cells undergo determination such that they will give rise to a particular tissue early on
38
Cell Differentiation
Specialization that occurs at the end of development Forms a specific type of specialized tissue cell Fate of a cell is determined early on, but does not differentiate into specialized tissue cell until later Involves complex series of intercellular interactions Example of gene regulation in development
39
How do differentiated cells express different cell functions?
Cell still contains entire genomes, but parts of genome that are not required for specialized function of cell are note expressed Due to epigenetic regulatory factors such as signals from other cells
40
Multipotent Stem Cells
Non terminally differentiated cells such as skin, liver, and blood cells that can regenerate these systems as needed These types of tissues are susceptible to injury
41
Gastrulation
A process in embryonic development in which the gastrula is formed Occurs in third week after fertilization First cell movements occur as cells begin to slowly move about the embryo Primitive streak is formed-mesoderm destined cells Three primary germ layers are formed: (1) ectoderm, (2) mesoderm, (3) endoderm
42
What’s the difference between totipotent, pluripotent, and multipotent stem cells?
Totipotent: Can become any cell, placenta or embryo Pluripotent: Can become any one of the initial three germ layers, part of embryo Multipotent: Can replace cells of a particular lineage, such as skin, liver, and blood
43
What is the fate of the cells in the ectoderm?
Epidermis of skin, nervous system, sensory organs
44
What is the fate of the mesoderm?
Skeleton, muscles, blood vessels, heart, blood, gonads, kidneys, dermis of skin
45
What is the fate of the cells in the endoderm?
Lining of digestive and respiratory tracts, liver, pancreas, thymus, thyroid
46
Neurulation
Process in the third week of embryonic development, in which the gastrula develops into a neurula Notochord (mesoderm) causes overlying ectoderm to thicken and form neural plate Notochord degenerates, and neural tube forms from neural plate to become spinal cord, brain, and most of nervous system
47
Neural Crest
Cells of the ectoderm that are close to the neural tube Function mostly as accessory cells to nervous system (Schwann cells), second order neurons of autonomic nervous system, and parts of endocrine system (adrenal medulla, C cells of thyroid) Neural crest cells undergo cell migration to travel to various locations in body
48
How is apoptosis essential for embryonic development?
Aids development of nervous system Aids operation of immune system Causes destruction of tissue between fingers and toes to create hands and feet in humans Damaged cells undergo apoptosis as well
49
How is apoptosis regulated?
Regulated by protein activity, as opposed to regulation at level of transcription of translation Proteins are present but inactive in healthy normal cell
50
Cell Induction
One cell type affects the direction of differentiation of another cell type
51
Senescence
Process by which cells stop proliferating in response to environmental stressors and are ultimately cleared away by immune cells Developmental process that allows shaping of tissues Occurs in embryonic development and aging
52
Prenatal Development
Occurs before birth, and begins w/ development of embryo Cleavage, blastula formation, gastrulation, neurulation, process of organ formation begins 9th week: major organs develop in final locations, considered a fetus 2nd trimester: not capable of independent survival 3rd trimester: growth in brain, not yet developed by parturition (birth) because too large
53
Motor Development
Takes infant from earliest stage (immobility) to independent walking Basic milestones of progress the same Cephalocaudal pattern: development head to toe Proximodistal pattern: Midline to periphery Progress starts with head, moves to trunk, moves down and out with limb movement Lifting of head > lifting of chest > sit with support > sit without support > walking with support > standing independently > walking independently
54
Puberty
Biological Changes that lead to sexual maturity Adolescent development includes psychosocial processes that accompany puberty Sexual maturation occurs in context of primary sex characteristics and secondary sex characteristics Reproductive hormones influence behavior
55
Adolescence
Socially designated period of rapid psychological and social change that is intertwined with pubertal development Involves rapid physical growth and sexual maturation

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