Human Development Flashcards Preview

BIOL-L112 Exam 4 > Human Development > Flashcards

Flashcards in Human Development Deck (89):
1

What happens when sperm and egg unite?

Form a zygote

2

How many sperm survive the trip to the egg?

A few thousand

3

How many sperm made during a lifetime?

525 Billion

4

How many sperm per ejaculate?

20-100 million

5

How many eggs at birth for Women?

2Million

6

How many eggs released during lifetime?

450 eggs

7

Do large or small animals have the largest sperm?

Small, it could be a matter of the resources they have available

8

How long does it take for sperm tail to develop?

9-10 Weeks

9

How long does it take for sperm production?

60 Days

10

What does the Sperm head contain?

DNA

11

Where is Mitochondira present in relation to sperm

Present in large amounts adjacent to the tail, synthesizes ATP

12

What is Acrosome?

Caps the head

13

What is a Centriole?

Enables first division of zygote to take place .

14

When will sperm mature?

Matures when it passes out of the testes, into the epididymis where secretions from the wall help them mature

15

Where is Sperm stored until needed?

In the last stretch of the epididymis until needed

16

Before ejaculation, sperm passes through what?

The vas deferns, the ejaculatory duct, and the urethra

17

What does Semen consist of?

Sperm and Secretions from accessory glands

18

What do Seminal Vesicles secrete?

Fructose (Nourishes Sperm) and Prostaglandins (Triggers contractions in the female tract thus aiding sperm movement)

19

Prostate Gland Secretions help to bufer the ___

acidity of the vagine. (pH 3.5-4). Fertility and Mobility is improved at pH 6

20

Bulbourethral Glands do what?

Secrete mucus-rich fluid into the urethra during arousal. This sperm mucus neutralizes any trace of acidity in urine left in the urethra

21

What doe a atypical ejaculation release?

40-350 million sperm

22

What does less than 20 million sperm during ejaculae mean?

Infertility

23

Fertilization, Step 1

The sperm squeezes through cells left over from the follicle

24

Fertilization, Step 2

The sperm's acrosomal enzymes digest the jelly coat surrounding the egg

25

Fertilization, Step 3

The plasma membranes of the sperm and egg fuse

26

Fertilization, Step 4

The sperm nucleus enter the egg cytoplasm

27

Fertilization, Step 5

The sperm and egg chromosomes intermingle

28

What is induction?

One group of cells influences the development of an adjacent group of cells.

29

When does development of embryonic devlopment first begin?

With Cleavage/

30

What is Cleavage?

Series of rapid cell divisions that results in a multicellular ball

31

Cleavage continues as ____

the embryo moves down the oviduct toward the uterus

32

When does a Blastocyst first form?

After 6-7 days after fertilization

33

What does a Blastocyst consist of?

Consists of a fluid-filled hollow ball with about 100 cells and a small clump of inner cells called the inner cell mass which forms the fetus

34

What happens 9 days after conception?

Embryo undergoes gastrulation, an organized migration of cells

35

How many main things occur during the Gastrula stage?

Three

36

Gastrula; Basic Body Plan #1

Ectoderm; Outer layer than forms the nervous system, skin, and retina

37

Gastrula; Basic Body Plan #2

Mesoderm; Middle layer that forms the heart, kidneys, muscles

38

Gastrula; Basic Body Plan #3

Endoderm; Lungs, Liver, the innermost layer that becomes the lining of the digestive tract

39

What is Programmed Cell Death?

Selectively kills cells to reshape the embryo and is used in formation of fingers and toes

40

What is Thalidomide used for?

Used for shrinking cancerous tumors before surgery

41

What is Thalidomide

Used for treating TB. Do not get pregnant while under treatment

42

What is DES?

Previously prescribed to prevent miscarriages. Granddaughters 40x greater chance of development lower genital tract clear-cell adoncarcinoma

43

What happens 8-9 Weeks After Fertilization?

Embryo is called a fetus. Has all organs an dbody parts. Limb buds have become tiny arms and legs

44

What is rapidly developing at 8-9 Weeks?

The Genitals

45

At 8-9 Weeks, what does SRY do?

Determines the maleness, is the determining gene. Codes for a protein involved in primary sex determination

46

What happens if SRY is present?

Embryo develops sperm producing testis

47

What happens if SRY is absent?

Gene called DAX1 produces an Anti-Testis factor (maleness inhibitor factor). Ovaries and eggs develop

48

Is secondary sex determination (breasts, hair, body type) determined by SRY?

No, it is determined by Hormones (Testosterone or Estrogen)

49

What happens at Week 10

Placenta is fully formed.

50

What is produced by the Placenta at 10 weeks?

Estrogen and Progesterone

51

At 10 weeks, do the mother's blood and fetal blood mix?

Mp. except for gases, viruses, drugs, drugs of abuse

52

What antibody can cross the placenta?

IgG

53

What is shown at 3-4 Months

Eyelashes, Eyebrows, Nipples
Increase in body length
Brain growth slow
Bone replaces cartilage

54

What is Week 12 known as?

The end of the First Trimester

55

When can the sex of the fetus be identified?

By the end of the First Trimester

56

How long does the Second Trimester Last?

13-27 Weeks

57

At about 14 weeks, the fetus is

2.4 inches long and looks human

58

At 20 Weeks, the fetus is

7.6 inches long, weighs 1lb, and has the face of an infant

59

Fetus length at full term

20 inches

60

Fetus weight at full term

7.5 pounds

61

What happens during Months 5-7

Kicking
Lanugo (Body covered by "down")
White Cheesy Substance (Venix Caseosa)
12" and 3 lbs
Eyes Open

62

When is the fetus able to survive outside the womb?

At 28 Weeks

63

The third trimister is a ..

Time of rapid growth and includes many important physical changes

64

At birth, a baby is

20 inches long and weights 6-8 pounds

65

What is Labor?

The birth of a child is brought about by a series of strong rhythmic contractions of the uterus

66

What is Oxytocins role in labor?

A powerful stimulant of the smooth muscle walls in the uterus, plays a key role in inducing labor

67

What is Prostaglandins role in Labor?

Induces labor. Contraction of Uterine smooth muscles and cervical ripening for the next 12-16 hours.

68

How many stages does Labor involve?

3

69

Labor; Step 1

Dilation; Longest, and opens cervix to 10cm.

70

What happens during Dilation?

Amniotic sac rptures. Explsion of mucus plug. Contractions become more intense and frequent

71

Labor; Step 2

Expulsion; results in the delivery of the child

72

Labor; Step 3

Delivery of the placenta; occurs within 15 minutes after the birth of the baby

73

Lactation; What do Estrogen and Progesterone contribute to?

The growth of mammary glands and ducts in the breast

74

During Lactation, wha tis secreted?

Prolactin

75

Lactation; After 1/2 days, what is produced?

Colostrum (Low fat, high IgA, anti-microbial factors) is produced

76

What does Oxytocin do during breastfeeding?

Forces breast tissues to contract and forces milk to the ducts

77

Oxytocin also forces...

uterine contractions so that the uterus can return to its normal size

78

If level of oxytocin is low,

the labor is intense. the cervix does not dilate. C-Section recommended.

79

Infertility is

the inability to have children after one year of trying

80

Male Inferility

Due to underproduction or poor sperm quality. Can be because of smoking, or by impotence (erectile dysfunction)

81

Female Infertility

Result from lack of eggs, failure to ovulate, or blocked oviducts

82

What is In Vitro Fertilization?

Begins with the administration of drugs that promote the development of multiple eggs

83

What is IVF followed by?

Surgical removal of eggs
Collection of Sperm
Fertilization of the eggs with sperm in Petri dish
Injection of the resulting embryos in a uterus

84

At around what age do females go through menopause?

Age 50, and its the cessation of ovulation and menstruation

85

How might menopause be adaptive?

Menopause might increase womens fitness by allowing her to invest more time and energy in her children and grandchilren instead of having more

86

Embryonic Stem Cells are ___

Totipotent; Can form all the cell types in the body.

87

Stem Cell Pros

Potential Cures for various things
Reduced Risk of Transplantation (Could possibly get copy of your own heart)

88

Stem Cell Cons

Destuction of Blastocyst
When does life begin
Should late fetuses be used for research
Temptation to clone humans?

89

Stem Cells Alternatives

Used of adult stem cells for bone marrow
Use umbilical cord or placental blood cells and store at birth