Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology 30 > Human Development: Chapter 7-8 > Flashcards

Human Development: Chapter 7-8 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Embryonic period of development

A

Takes place over the first 8 weeks, or ⅔ of the first trimester

  • cells divide and become redistributed
  • tissues and organs form
  • structures that support and nourish the developing embryo form
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fetal period of development

A

Takes place from the start of the ninth week through birth, or the remaining third and second
and third trimesters
- body grows rapidly
- organs begin to function and coordinate to form organ systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Fertilization

A

Joining of male and female gametes (sperm and egg cell) to form a cell (zygote). This cell will have 46 chromosomes, 23 from the sperm, 23 from the egg. (23 chromosome pairs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Female preparation for fertilization

A
  1. Egg is released from an ovary and is swept into an oviduct
  2. Egg is carried to the uterus by muscular contractions and wavelike actions of cilia that line the oviduct. (Takes about 4 days, and the egg must be fertilized within 12 to 24 h of its release in order to develop further)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Male preparation for fertilization

A

Several hundred million sperm cells exit male’s urethra during ejaculation
Once sperm enters the vagina, they must go through the cervix, uterus, and oviduct where the egg is. (Most sperm does not survive, some are destroyed in the vagina’s toxic environment, some go through the wrong oviduct.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Egg structure

A

The plasma membrane of the egg is surrounded by zona pellucida (thin layer of protein and carbohydrate). The zona pellucida is surrounded by the corona pellucida (several jelly-like layers of follicle cells that loosely adhere to one another. Follicle cells were a source of nourishment for the egg when it was an ovarian follicle.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Fertilization process and formation of a zygote

A

When the sperm meets the corona radiata, the sperm’s enzyme-containing acrosome (“cap” around the nucleus) releases its contents
Enzymes digest their way through the corona and zona pellucida. (Many sperms are required for this activity.) The sperm advances further by lashing of its tail.
Once a sperm enters the egg, the egg’s plasma membrane depolarizes, preventing other sperm from binding with and entering it.
Within 12 h of the sperm’s nucleus entering the egg, membranes of sperm nucleus and egg nucleus disappear. 23 chromosomes in the ovum join with the 23 chromosomes in the sperm.
Fertilization is now complete and a zygote is formed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Zygote

A

A cell formed by the union of two gametes; the product of fertilization; has 23 pairs of chromosomes (making a total of 46 chromosomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Polyspermy and prevention

A

When an egg is fertilized by more than one sperm
→ prevention: when one sperm enters the egg, the egg’s plasma membrane depolarizes,
preventing other sperm from with and entering it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cleavage

A

The process of cell division without cell growth
30h of fertilization: the 0.1mm zygote divides by mitosis for the first time, making two new cells. These cells divide, making four, then eight, then so on. (Cells get smaller each division, so zygote remains about 0.1mm.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Morula

A

Sphere zygote made of 16 cells.

  • Reaches uterus within 3-5 days of fertilization
  • Begins to fill with fluid that diffuses from the uterus. As the fluid-filled space develops, two different groups of cells form, creating a blastocyst
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Blastocyst

A

(Greek: “germ pouch”) Mammalian embryo at the stage in which it is implanted in the wall of the uterus and consists of a nearly hollow ball of cells; is made up of two groups of cells: the trophoblast and inner cell mass.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Trophoblast

A

(“Nourishment of the germ”) A group of cells that forms the outer layer of the blastocyst
- Will develop into a chorion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Chorion

A

(“Membrane”) Develops from a trophoblast, and develops into the placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Placenta

A

Structure that provides nutrients and oxygen to, and removes wastes from, the developing offspring.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Inner cell mass

A

(or embryoblast) The other group of cells of the blastocyst. Will develop into the embryo.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Implantation

A

The process of attachment of the embryo to the endometrium
→ between the fifth and seventh day after fertilization, blastocyst attaches itself to the
endometrium (lining of the uterus), with the inner cell mass against the endometrium.
→ trophoblast secretes enzymes that digest some of the tissues and blood vessels of the endometrium, and the blastocyst slowly sinks into the uterine wall
- Implantation is completed by the tenth or fourteenth day. The woman is technically pregnant after implantation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Human chorionic gonadotropin (hCG)

A

Hormone secreted by the trophoblast at the time of implantation of the embryo; prevents degeneration of the corpus luteum.
- same effects as luteinizing hormone (LH)
- secretes estrogen and progesterone, maintaining endometrium and preventing menstruation
→ hCG secretion continues at a high level for two months, then declines to low at the end of
four months, as the corpus luteum is less important as a source of hormones after the first trimester. (By now, the placenta secretes enough estrogen and progesterone to maintain endometrium.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Corpus luteum

A

Yellow-ish, gland-like structure that develops from a follicle that has matured and released its egg (ovum); it produces progesterone and some estrogen; if pregnancy doesn’t occur, it degenerates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Gastrulation

A

The formation of the three primary germ layers in embryogenesis.
→ Once implantation finishes, inner cell mass changes. Space forms between the inner cell mass and the trophoblast called the amniotic cavity. (Will fill with fluid and is the location where baby will develop) Amniotic cavity forms within a sac called the amnion.
→ Inner cell mass flattens into a disk-shaped structure called the embryonic disk which is
supported by a short stalk that connects blastocyst with the endometrium
→ Embryonic disk is consisted of two layers: outer ectoderm (closer to amniotic cavity) and inner endoderm. A third layer forms between the endoderm and ectoderm, and is called the mesoderm.
- Creates a gastrula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Primary germ layers

A

The embryonic disk’s layers. Includes outer ectoderm, inner endoderm, and the mesoderm between both.
Embryonic disk is consisted of two layers: outer ectoderm (closer to amniotic cavity) and inner endoderm. A third layer forms between the endoderm and ectoderm, and is called the mesoderm. (This process is gastrulation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Differentiation

A

Cellular process that enables a cell to develop a particular shape and to perform specific functions that are different from the functions of other cells. (Cells, tissues, and organs of the body are derived from the primary germ layers through differentiation.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Morphogenesis

A

Series of events that form distinct structures of the developing organism. Derives from differentiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does the ectoderm (outer layer) turn into?

A
  • outer skin (epidermis) and associated structures (hair, - - nails, sweat glands, mammary gland)
  • nervous tissue and sense organs
  • pituitary gland
  • tooth enamel
  • adrenal medulla
  • eye lens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does the mesoderm (middle layer) turn into?

A
  • dermis of skin
  • cellular lining of blood vessels, lymphatic vessels, body cavities
  • muscle tissue
  • connective tissue (including bone, cartilage, blood)
    adrenal cortex
  • kidneys and ureters
  • heart
  • spleen
  • internal reproductive organs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the endoderm (inner layer) turn into?

A
  • cellular lining of respiratory tract, digestive tract, urinary bladder, urethra
  • liver (most)
  • tonsils (partial)
  • gallbladder
  • parathyroid glands
  • pancreas
  • thyroid glands
  • thymus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Neurulation

A

in embryogenesis, the process of forming the neural tube, which develops into the brain and spinal cord
→ During the third week, a thickened band of mesoderm cells develops along the back of the embryonic disk. This will become the baby’s back and come together to form a rod-like structure called the notochord
→ Notochord will form the basic framework of the skeleton
→ Nervous system develops from the ectoderm that is located just above the notochord
→ Cells along the surface of the notochord begin to thicken. Folds develop on each side of a groove along this surface. When these folds fuse, they become the neural tube, that develops into the brain and spinal cord
→ Marks the beginning of organ formation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Third week into fertilization

A

Neurulation, and reddish bulge that becomes the heart. By the 18th day, heart starts beating.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Fourth week into fertilization

A

Embryo is about 0.6cm long)Rapid growth and development. Blood cells form and fill developing blood vessels. Lungs and kidneys that shape. Small buds (what will be arms and legs) appear. Distinct head, eyes, ears and nose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Fifth week into fertilization

A

(~1.3cm) Embryo’s head is large compared to its body. Eyes open, but no eyelids or irises. Cells in brain are differentiating quickly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Sixth week into fertilization

A

Brain develops rapidly. Limbs lengthen and flex slightly. Gonads produce hormones that will influence development of external genitalia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Seventh/Eighth week into fertilization

A

(Size and weight of paper clip by end of eighth week) Embryo has distinct human characteristics. Organs are formed. Nervous system is starting to coordinate body activity. Skeleton of cartilage is formed. Eyes are developed, but shut closed to prevent accidental poking from fingers. Nostrils are developed, but plugged with mucus. External genitalia are still forming, but are undifferentiated. Physical sex is not determined, but genetic sex is. After the 8th week, the embryo is now considered a fetus. 90% of organs and structures of a human are developed.

33
Q

Ninth week into fertilization

A

Skeleton cartilage is turned into bone.

34
Q

Extra-embryonic structures

A

Any in an intricate system of membranes external to the embryo; responsible for the protection, nutrition, respiration, and excretion of the embryo and fetus.
During birth, these membranes are expelled from the uterus (afterbirth)

35
Q

Allantois

A

Extra-embryonic membrane that forms the foundation for the umbilical cord.

36
Q

Amnion

A

Extra-embryonic membrane that forms a transparent sac that encloses and protects the embryo and fetus

37
Q

Chorion

A

in humans, membrane developed from the trophoblast layer of the blastocyst; develops into the fetal part of the placenta; is the outermost of the extra-embryonic membranes which encloses all the other membranes, as well as the embryo

38
Q

Yolk Sac

A

one of the extra-embryonic membranes suspended from the abdominal area of the embryo; in humans, serves no nutritive function, but contributes to the formation of the digestive tract and produces the first blood cells and the future egg (ova) or sperm cells

39
Q

Placenta

A

in most pregnant mammals, a disk-shaped organ within the uterus that is rich in blood vessels; attaches the embryo or fetus to the uterine wall and facilitates metabolic exchange
→ Begins to form by the end of the second week after fertilization. Finger-like projections called chorionic villi from the chorion extend into the uterine lining and establishes the beginnings of the placenta.
→ Placenta is fully developed around 10 weeks.
→ One part of the placenta - the chorion tissue - comes from the embryo. The other part consists of blood pools from the mother’s circulatory system. Blood system of embryo and mother are separate but very close in proximity. This proximity allows nutrients and oxygen to diffuse from the mother’s circulatory system to the developing baby and for wastes to leave the baby’s circulation and enter the mother’s for excretion

40
Q

Nutritional function of the placenta

A
  • transports nutrients (ex. glucose, amino acids, fatty acids, minerals and vitamins) from mother’s blood to fetus’ blood
  • stores nutrients (ex. carbohydrates, proteins, iron, and calcium) in early pregnancy and releases them to the fetus later; when fetal demand is greater than the mother can absorb from her diet
41
Q

Excretory function of the placenta

A
  • transports wastes (ex. urea, ammonia, and creatinine) from the fetal blood to the mother’s blood
42
Q

Respiratory functions of the placenta

A
  • transports oxygen from the mother to the fetus and carbon dioxide from the fetus to the mother
43
Q

Endocrine functions of the placenta

A
  • secretes hormones, such as estrogen, progesterone, and human chorionic gonadotropin
  • allows hormones from the fetus to diffuse into the mother’s blood and hormones from the mother to diffuse into the fetus’ blood
44
Q

Immune functions of the placenta

A
  • transports antibodies from the mother into the fetus’ blood to provide passive immunity
45
Q

Teratogens

A

Any agent that causes structural abnormality of the developing fetus due to exposure during pregnancy
→ Anything that the mother ingests or inhales can end up in her blood, which could pass through the placental system into the fetus’ blood. *Especially significant in the first nine weeks when developing organs are super sensitive

46
Q

Teratogens: Smoking effects

A

Can constrict fetus’ blood vessels, preventing the fetus from getting enough oxygen. Baby tends to come out underweight. Increases chances of premature births, stillbirths, and miscarriages. Evidence of behavioural problems and reduced intellectual ability in children of smoking mothers

47
Q

Teratogens: Alcohol effects (FASD)

A
  • Fetal alcohol spectrum disorder:or FAS (fetal alcohol syndrome) term used to describe all the disorders related to alcohol consumption during pregnancy
    → Alcohol can affect fetus’ brain, central nervous system, and physical development
    → Babies are likely to have decreased weight, height, and head size, along with malformations of the face and head
    → Children show various degrees of learning and memory difficulties and exhibit unusual aggression or personality disorders
    *All women are warned not to drink when pregnant, trying to become pregnant, or
    breastfeeding.
48
Q

Teratogens: Prescriptions or Over-the-Counter drug effects

A
  • Many of these medications have teratogenic properties. Antibiotics (ex. tetracycline), acne medications, anti-thyroid drugs (for hyper and hypothyroid conditions), and some anticancer drugs can have dangerous effects on the fetus.
    → Thalidomide is the drug with the most teratogenic effects. First prescribed in the 1950s for morning sickness. Many babies were born with missing or deformed limbs.Thalidomide is now used for treating skin conditions (ex. leprosy) and is studied for its potential to treat cancer of the bone marrow (myeloma)
49
Q

Teratogens: Nutrients effects

A

Nutrients (especially vitamins), when ingested in large amounts, can have teratogenic effects.
→ ex. Vitamin C: fetus becomes accustomed to large doses, and when supply drops after birth, the baby develops symptoms of vitamin C deficiency (scurvy), bruising easily, and prone to infection.

50
Q

Other teratogenic agents

A

radiation, such as x-rays and pollutants, such as PCBs and organic mercury compounds.

51
Q

Teratogenic: Environmental containments effects

A

(such as mercury, lead, cadmium, DDT, and PCBs) ex. women in Aboriginal communities rely on fish and wildlife for food. These animals contain environmental contaminants through the food chain, starting from industrial discharges and runoff from contaminated land.
→ Contaminants have been found in pregnant women, the umbilical cord, and breast milk of nursing mothers.
→ Women with contaminants have higher number of miscarriages, lower birth-weight babies, babies who have difficulty fighting infections and disease, and are developmentally delayed.

52
Q

Process of parturition

A

Act/process of giving birth.
→ Begins with uterine contractions. (Labour is marked by uterine contractions that occur every
15 to 20 minutes and last for 40 seconds or longer.)
→ Onset of labour has both hormonal and neural components. Positive feedback mechanism can explain the onset and continuation of labour.
→ Uterine contractions are induced by stretching of the cervix,, which also instigates the release of oxytocin from the posterior pituitary gland. Oxytocin stimulates the uterine muscles, both directly and through the action of prostaglandins. Contractions push the fetus downward, and the cervix stretches even more.

53
Q

Stages of parturition

A
  • Dilation stage: Uterine contractions and oxytocin cause cervix to open/dilate. Amniotic sac breaks and the amniotic fluid is released through the vagina. (Lasts from 2 to 20 hours.)
  • Expulsion stage: Forceful contractions push baby through the cervix to the birth canal. As the baby moves through the canal, the head rotates, making it easier for the body to pass through the canal. (Lasts from 0.5 to 2 hours)
  • Placental stage: (afterbirth) About 10-15 minutes after birth, the placenta and umbilical cord are expelled from the uterus. Expelled placenta is the afterbirth.
54
Q

Hormones in parturition and their functions.

A
  • oxytocin: secreted during childbirth. Stretching of the uterus and cervix stimulates release of oxytocin from the posterior pituitary.
  • prolactin: hormone needed for milk production. After birth, anterior pituitary begins to produce and secrete prolactin.
  • oxytocin (breastfeeding): causes contractions within the mammary lobules to release milk.
55
Q

Stem cells features and types

A

stem cells: unspecialized or undifferentiated cells. These cells have not yet begun to develop into cell types that make up the human body (red blood cells, muscle cells, etc.)
→ FEATURES
Stem cells can replicate for a long time by dividing
Under suitable laboratory conditions, stem cells can be coaxed to give rise to cells with special functions (ex. heart muscle cells and neurons/nerve cells)
→ TYPES
adult stem cells: (aka somatic stem cells) found in all humans of all ages. One medical use is found in umbilical cords of newborns.
embryonic stem cells: comes from embryos, about four or five days after fertilization.
→ Are pluripotent, which means they can become many different types of cells in the human body.

56
Q

In vitro fertilization

A

when embryos are produced in a lab, and can be implanted in a woman. However, more are produced than are implanted in a woman. This leads to ethical considerations.

57
Q

Reasons for male infertility/sterility

A
  • obstruction in deferens or epididymis, can be caused by complications from STIs or other blockages in testicles
  • low sperm count, caused by overheated testicles, smoking, or alcohol intake
  • high proportion of abnormal or non-viable sperm, caused by overheated testicles, toxic chemicals or radiation, or infections such as STIs
  • inability to achieve erection or ejaculation, caused by vascular disease, nervous system injury, stress, hormonal imbalance, medication, smoking, and alcohol intake
58
Q

Reasons for female infertility/sterility

A
  • blocked oviducts, caused by STIs
  • failure to ovulate, caused by hormonal imbalances, sometimes caused by malnourishment
  • endometriosis, when endometrial tissues grow outside the uterus
  • damaged eggs, caused by environmental factors, such as exposure to toxic chemicals or radiation
59
Q

Technologies that enhance reproductive potential: artificial insemination (AI)

A

sperm are collected and concentrated before being placed in the woman’s vagina. Sometimes sperm is from the male partner or a stranger. Sperm banks are used for this purpose

60
Q

Technologies That Enhance Reproductive Potential: in vitro fertilization (IVF)

A

for women with blocked oviducts. Ultrasound machines are used to identify specific follicles that are close to ovulation. Immature eggs are retrieved from these follicles. Eggs are combined with sperm in laboratory glassware. After fertilization, the embryo is placed in the uterus

61
Q

Technologies That Enhance Reproductive Potential: gamete intrafallopian transfer (GIFT)

A

egg and sperm is brought together in the oviduct rather than in vitro. Higher success rate than IVF.

62
Q

Technologies That Enhance Reproductive Potential: surrogate mothers

A

another woman to carry the baby for the couple. Can use AI or IVF.

63
Q

Technologies That Enhance Reproductive Potential: superovulation

A

production of multiple eggs as a result of hormone treatment. Stimulates follicle development and ovulation.

64
Q

Technologies that Reduce Reproductive Potential

A

All technologies that prevents conception are forms of contraception, or birth control.

65
Q

Technologies that Reduce Reproductive Potential: abstinence

A

not having sex at all. Gives almost total protection from STIs.

66
Q

Technologies that Reduce Reproductive Potential: surgical sterilization in females (tubal ligation)

A

cutting the oviducts and tying off the cut ends. Ensures that ovum never encounters sperm and never reaches the uterus. Ovum ends up disintegrating in the oviduct. (Almost 100% effective)

67
Q

Technologies that Reduce Reproductive Potential: surgical sterilization in males (vasectomy)

A

ductus deferens is cut and tied. Man is still able to have an erection and ejaculate, but his semen does not contain any sperm. (Almost 100% effective)

68
Q

Technologies that Reduce Reproductive Potential: hormone treatments

A

Changes the balance of reproductive hormones within a woman’s body.

  • Hormone medications can be taken orally (oral contraceptive or birth control pill), by injection, or by implants inserted under the skin.
  • Artificial hormones mimic effect of progesterone and inhibit release of FSH and LH from anterior pituitary. Therefore, the woman does not ovulate.
  • Effectiveness ranges from 90-99%
  • Side effects include increased risk of blood clots, strokes, and breast cancer
69
Q

Technologies that Reduce Reproductive Potential: hormone treatments - the “morning after pill”

A

Intensive hormone treatment that is NOT a form of contraception. It is used by the woman to reduce the risk of conception following unprotected sexual intercourse.
- several pills taken within three days after intercourse. These pills deliver high doses of synthetic estrogen and progesterone. These hormones disrupt the ovarian cycle and can prevent or delay ovulation
- if fertilization has already taken place, hormones can also prevent the embryo from implanting in the uterus
common side effects include vomiting and painful cramps
- within 24 hrs of unprotected intercourse: - 95% effectiveness
- 24-48 hrs: 85%
- 48-72 hrs: 5%

70
Q

Technologies that Reduce Reproductive Potential: physical/chemical barriers - male/female condoms

A

about 98% effective. Offers some protection of STIs

71
Q

Technologies that Reduce Reproductive Potential:

physical/chemical barriers - latex cap

A

fits over the cervix and is about 90% effective

72
Q

Technologies that Reduce Reproductive Potential:

physical/chemical barriers - contraceptive sponge

A

effectiveness ranges from 70-90% depending on whether the homan has given birth and the care taken in using it

73
Q

Technologies that Reduce Reproductive Potential:

physical/chemical barriers - spermicide

A

chemical barriers that kill sperm, includes jellies, foams, and creams. Effectiveness is about 75%

74
Q

Technologies that Reduce Reproductive Potential:

Natural family planning

A
  • refraining from sexual intercourse during the time of the woman’s cycle when she is most fertile (week before her ovulation to a day or two afterward).
  • a woman’s cycle can vary from month to month, therefore the couple must pay careful attention to the subtle signals of the woman’s body, such a body temperature and properties of the cervical mucus.
  • among the least reliable forms of birth control, with about a 70% effectiveness rate
75
Q

Umbilical cord:

A

Near the end of the eighth week, as the yolk sac shrinks and the amniotic sac enlarges, the umbilical cord forms.

  • rope-like structure that averages about 60 cm long and 2 cm in diameter (can even be as long as 300 cm or short as a few mm)
  • leads from navel of the fetus to the center of the placenta
  • has two arteries, which transports oxygen-depleted blood from the fetus into the placenta. Also has one vein, which brings oxygen-rich blood to the fetus
  • has natural twists because the umbilical vein is longer than the arteries are
  • after birth, umbilical cord is clamped and cut and now the baby must depend on itself
76
Q

Caesarean section (c-section)

A

another form of birth other than the regular “breech birth”

  • physician makes incisions in mother’s abdomen and uterus, and delivers the baby through the incision
  • mother with STI or a small pelvis can have c-sections as well to protect herself from injury and her baby from infection
77
Q

Lactation and the hormones

A

hormones control lactation, the secretion and formation of breast milk in the mother
→ prolactin (PRL): the hormone needed for milk production
- not secreted during pregnancy as high levels of estrogen and progesterone suppress its production in the anterior pituitary
- after birth, then the anterior pituitary secretes PRL and milk production starts within a few days
- before milk production, the breasts secrete colostrum, a thin yellowish fluid that is similar to milk but contains more protein and less fat
- both colostrum and milk contain antibodies from mother

78
Q

Suckling reflex and hormones

A

When a baby suckles, it stimulates nerve endings in the nipple and areola
- nerve impulses travel to hypothalamus, which in turn stimulates the posterior pituitary to release oxytocin
→ oxytocin (OCT): causes contractions within the mammary lobules
- mammary lobules contain alveoli, which are sacs with cells that produce milk. The lobules end in mammary ducts at the nipple
- contractions within lobules cause milk flow to ducts, which the baby draws out by suckling
- if suckling does not occur or stops, milk production stops within a few days

Biology 30 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions