Chapter 22 - Growth, development, and aging Flashcards

1
Q

prenatal period vs postnatal period

A

The prenatal period begins at conception and ends at birth; the postnatal period begins at birth and continues until death.

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2
Q

conception

A

also called fertilization
It is the moment the female ovum and the male sperm cells unite to form a zygote; it is the beginning of the life of an organism.

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3
Q

embryology

A

the branch of biology and medicine concerned with the study of embryos and their development

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4
Q

morula

A

an early-stage embryo consisting of 16 cells (called blastomeres) in a solid ball contained within the zona pellucida

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5
Q

zona pellucida

A

a glycoprotein layer surrounding the plasma membrane of mammalian oocytes

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6
Q

blastomere

A

a type of cell produced by cleavage (cell division) of the zygote after fertilization and is an essential part of blastula formation

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7
Q

blastulation vs. blastula

A

Blastulation is the stage in early animal embryonic development that produces the blastula. The blastula (from Greek βλαστός (blastos meaning sprout) is a hollow sphere of cells (blastomeres) surrounding an inner fluid-filled cavity (the blastocoel).

Embryonic development begins with a sperm fertilizing an egg cell to become a zygote, which undergoes many cleavages to develop into a ball of cells called a morula. Only when the blastocoel is formed does the early embryo become a blastula. The blastula grows to become a blastocyst.

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8
Q

blastocyst

A

A blastula that has developed to the point where differentiation begins in its cells. The blastomeres in the blastula’s outer cell layer are replaced by a trophoblast.

As the blastocyst develops, it forms a structure with two cavities, the yolk sac and amniotic cavity.

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9
Q

trophoblast

A

A thin layer of cells that helps a developing embryo attach to the wall of the uterus, protects the embryo, and forms a part of the placenta.

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10
Q

pluripotent

A

(of an immature or stem cell) capable of giving rise to several different cell types

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11
Q

laparoscope

A

a fiber-optic instrument inserted through the abdominal wall to view the organs in the abdomen or permit small-scale surgery

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12
Q

yolk sac

A

In humans, a sac involved with the production of blood cells in the developing embryo.

The yolk sac is most important in animals, such as birds, that depend heavily on yolk as the sole source of nutrients for the developing embryo. In these animals, the yolk sac digests the yolk and provides the resulting nutrients to the embryo.

Because uterine fluids provide nutrients to the developing human embryo until the placenta develops, the function of the yolk sac is not a nutritive one. Instead, it has other functions—including production of blood cells.

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13
Q

amniotic cavity

A

The amniotic cavity is the closed sac between the embryo and the amnion, containing the amniotic fluid.

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14
Q

amnion

A

A membrane that closely covers the human and various other embryos when they are first formed. It fills with amniotic fluid, which causes the amnion to expand and become the amniotic sac that provides a protective environment for the developing embryo.

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15
Q

chorion

A

The outermost fetal membrane around the embryo in mammals, birds and reptiles. It develops from an outer fold on the surface of the yolk sac, which lies outside the zona pellucida (in mammals).

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16
Q

in vitro fertilization

A

The Latin term in vitro means, literally, “within a glass.” In the case of in vitro fertilization, it refers to the glass laboratory dish where an ovum and sperm are mixed and where fertilization occurs.

In the classic technique, the ovum is obtained from the woman by first inserting a fiber-optic viewing instrument called a laparoscope through a very small incision in her abdomen. After it is in the abdominal cavity, the device allows the physician to view the ovary, puncture it, and “suck up” an ovum from a mature follicle. Over the years refinements to this technique have been made, and less invasive procedures are currently being used.

After fertilization in a laboratory dish and about 2.5 days’ growth in a temperature-controlled environment, the developing zygote (which by then has reached the 8- or 16-cell stage) is placed by the physician into the mother’s uterus. If implantation is successful, growth will continue and the subsequent pregnancy will progress. In the most successful fertility clinics in the United States, a normal term birth will occur in about 30% of in vitro fertilization attempts.

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17
Q

gastrulation

A

Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells) is reorganized into a multilayered structure known as the gastrula.

Before gastrulation, the embryo is a continuous epithelial sheet of cells; by the end of gastrulation, the embryo has begun differentiation to establish distinct cell lineages, set up the basic axes of the body (e.g. dorsal-ventral, anterior-posterior), and internalized one or more cell types including the beginnings of the gastrointestinal tract.

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18
Q

germ layer

A

a primary layer of cells that forms during embryonic development

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19
Q

gastrula

A

An embryo at the stage following the blastula. It has a hollow cup-shaped structure having three layers of cells.

The gastrula is trilaminar (“three-layered”). These three germ layers are known as the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer).

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20
Q

Bilateria

A

also called bilaterians
They are animals with bilateral symmetry as an embryo, i.e. having a left and a right side that are mirror images of each other.
Humans, cats, monkeys, frogs, and sharks are just some examples.

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21
Q

choriocarcinoma

A

A malignant, fast-growing tumor that develops from trophoblastic cells (cells that help an embryo attach to the uterus and help form the placenta). Almost all choriocarcinomas form in the uterus after fertilization of an egg by a sperm.

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22
Q

chorionic villi

singular: chorionic villus

A

Chorionic villi are villi that sprout from the chorion to provide maximal contact area with maternal blood.

They are an essential element in pregnancy.

Branches of the umbilical arteries carry embryonic blood to the villi. After circulating through the capillaries of the villi, blood returns to the embryo through the umbilical vein.

Thus, villi are part of the border between maternal and fetal blood during pregnancy.

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23
Q

lacuna

A

(1) a blank space or a missing part: GAP

(2) a small cavity, pit, or discontinuity in an anatomical structure

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24
Q

villi

singular: villus

A

(biology) A small projection from a membrane, particularly those found in the mucous membranes of the intestines.
(botany) One of the fine soft hairs on fruits, flowers, and other parts of plants.

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25
Q

parturition

A

the action or process of giving birth to offspring: childbirth

26
Q

gestation period

A

also simply called gestation

it is the entire length of pregnancy, from conception to birth, typically lasting 39 weeks (approximately 9 months)

the gestation period is typically divided into 3-month segments called trimesters

27
Q

three stages of prenatal development

A

The process of prenatal development (gestation) occurs in three main stages.

Germinal stage: Weeks 1-2. It starts as a zygote which transforms into a blastocyst. That blastocyst then attaches to the uterus (this is called implantation) and starts the next stage.
Embryonic stage: Weeks 3-8. Embryo forms the basic structures of the human body and becomes a fetus.
Fetal stage: Week 9 to birth. Fetus develops slowly into a fully formed baby.

Remember: zygote -> morula -> blastula -> blastocyst -> gastrula -> organogenesis

(zygote to blastocyst is germinal stage, gastrula then organogenesis occur in the embryonic stage, and organogenesis continues until birth)

28
Q

embryo vs fetus

A

When the baby-to-be is in the germinal or embryonic stage, it is called an embryo. When it moves into the fetal stage, it is called a fetus. It is mostly an arbitrary line.

However, an embryo is still in the process of laying the groundwork for what will later be the body organs. A fetus is characterized by the presence of all the major body organs, though they will not yet be fully developed and functional and some not yet situated in their final anatomical location.

29
Q

histogenesis

A

the differentiation of cells into specialized tissues and organs during growth

30
Q

organogenesis

A

the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation (the ectoderm, endoderm, and mesoderm) form the internal organs of the organism

31
Q

teratogen

A

an agent or factor which causes malformation of an embryo

32
Q

birth defect

A

a developmental problem present at birth

33
Q

mutagen

A

an agent, such as radiation or a chemical substance, which causes genetic mutation

34
Q

gerontology

A

the scientific study of old age, the process of aging, and the particular problems of old people

35
Q

geriatrics

A

the branch of medicine or social science dealing with the health and care of old people

36
Q

three stages of labor

A

Labor is the process that results in the birth of a baby. It has three stages:
1. Stage 1—period from onset of uterine contractions until dilation of the cervix is complete
2. Stage 2—period from the time of maximal cervical dilation until the baby exits through the vagina
3. Stage 3—process of expulsion of the placenta through the vagina
(dilation = opening up)

The process normally begins with the fetus taking a head-down position against the cervix. A breech birth is one in which the fetus fails to turn head downward and consequently the feet are born first. This condition usually requires the baby to be born by cesarean section. Often called simply a C-section, it is a surgical procedure in which the newborn is delivered through an incision in the abdomen and uterine wall. The procedure may be done when abnormal conditions of the mother or fetus (or both) make normal vaginal delivery hazardous or impossible.

37
Q

pre-labor

A

The early signs before labor starts. It is the body’s preparation for real labor.

As pregnancy draws to a close, the uterus becomes “irritable” and, ultimately, muscular contractions begin and cause the cervix to dilate or open, thus permitting the fetus to move from the uterus through the vagina, or “birth canal,” to the exterior. When contractions occur, the amniotic sac, or “bag of waters,” ruptures, and labor begins.

38
Q

Apgar score

A

A test given to newborns soon after birth. This test checks a baby’s heart rate, muscle tone, and other signs to see if extra medical care or emergency care is needed. The test is usually given twice: once at 1 minute after birth, and again at 5 minutes after birth.

There are five things the test checks for, represented by the backronym APGAR. Each thing is between 0 and 2 points, with 2 being the best. A healthy baby scores a 10 in total.

APGAR stands for Appearance, Pulse (heartrate), Grimace (crying), Activity (reflexes), and Respiration.

39
Q

quickening

A

the first recognizable movements of the fetus (e.g. the baby’s kick)

40
Q

antenatal

A

(from the Latin ante, “before,” natus, “birth”)

occurring before birth; prenatal

41
Q

ultrasound

A

1: vibrations of the same physical nature as sound but with frequencies above the range of human hearing
2: the diagnostic or therapeutic use of ultrasound and especially a noninvasive technique involving the formation of a two-dimensional image used for the examination and measurement of internal body structures and the detection of bodily abnormalities
— called also sonography
3: a diagnostic examination using ultrasound

An image produce by ultrasound is called a sonogram or ultrasonogram.

42
Q

fetal alcohol syndrome (FAS)

A

A condition in a child that results from alcohol exposure during the mother’s pregnancy. Fetal alcohol syndrome causes brain damage and growth problems. The problems caused by fetal alcohol syndrome vary from child to child, but defects caused by fetal alcohol syndrome are not reversible.

43
Q

amniotic fluid

A

the protective liquid contained by the amniotic sac

44
Q

puberty

A

The process of physical changes through which a child’s body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs.

Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Until the maturation of their reproductive capabilities, the pre-pubertal physical differences between boys and girls are the external sex organs.

45
Q

spermarche

A

also known as semenarche
the beginning of development of sperm in boys’ testicles at puberty
also refers to the first ejaculation a male ever has

46
Q

spermaturia

A

a human disease characterized by the presence of sperm in the urine

47
Q

pubarche

A

the first appearance of pubic hair at puberty

48
Q

viviparity vs. oviparity

A

Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the mother.

49
Q

thelarche

A

also known as breast budding
It is the onset of secondary breast development, which often represents the beginning of pubertal development. It is the stage at which male and female breasts differentiate due to variance in hormone levels; however, some males have an abnormal condition in which they develop breasts, termed gynecomastia.

50
Q

gynecomastia

A

the abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogen and androgen

51
Q

androgen

A

Any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes the embryological development of the primary male sex organs, and the development of male secondary sex characteristics at puberty. Androgens are synthesized in the testes, the ovaries, and the adrenal glands.

The major androgen in males is testosterone.

Although androgens are commonly thought of only as male sex hormones, females also have them, but at lower levels: they function in libido and sexual arousal. Also, androgens are the precursors to estrogens in both men and women.

52
Q

estrogen

A

A category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3).

In addition to their role as natural hormones, estrogens are used as medications, for instance in menopausal hormone therapy, hormonal birth control and feminizing hormone therapy for transgender women and nonbinary people.

Estrogen levels are significantly lower in males than in females, but nevertheless have important physiological roles in males.

53
Q

primary characteristics vs. secondary sex characteristics

A

Primary sexual characteristics are present at birth and comprise the external and internal genitalia (e.g., the penis and testes in males and the vagina and ovaries in females).

Secondary sexual characteristics are those that emerge during the prepubescent through postpubescent phases (e.g. breasts enlarging in females)

54
Q

stages of childhood

A

Childhood is the age span ranging from birth to adolescence.

Childhood is divided up into the developmental stages of infancy (earliest stage of life), toddlerhood (learning to walk), early childhood (play age), middle childhood (school age), and adolescence (onset of puberty).

55
Q

adolescence

A

a transitional stage of physical and psychological development that generally occurs during the period from puberty to legal adulthood (age of majority)

56
Q

senescence

A

(1) the condition or process of deterioration with age

(2) loss of a cell’s power of division and growth

57
Q

neonate

A

a newborn child, especially a child less than a month old

58
Q

dementia

A

a general term for loss of memory, language, problem-solving and other thinking abilities that are severe enough to interfere with daily life. Alzheimer’s is the most common cause of dementia

59
Q

neonatology

A

a medical and nursing specialty concerned with the diagnosis and treatment of disorders of the newborn

60
Q

endogenous

A
  1. growing or produced by growth from deep tissue (e.g. endogenous plant roots)
  2. caused by factors inside the organism or system
  3. produced or synthesized within the organism or system.
61
Q

orthopedics

A

the branch of medicine dealing with the correction of deformities of bones or muscles