Development of the human body

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"Developmental" redirects here. Development of the human body_sentence_0

For other uses, see Development. Development of the human body_sentence_1

Development of the human body is the process of growth to maturity. Development of the human body_sentence_2

The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. Development of the human body_sentence_3

The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Development of the human body_sentence_4

Further growth and development continues after birth, and includes both physical and psychological development, influenced by genetic, hormonal, environmental and other factors. Development of the human body_sentence_5

This continues throughout life: through childhood and adolescence into adulthood. Development of the human body_sentence_6

Before birth Development of the human body_section_0

Main articles: Human embryonic development and Prenatal development Development of the human body_sentence_7

Development before birth, or prenatal development (from Latin natalis 'relating to birth') is the process in which a zygote, and later an embryo and then a fetus develops during gestation. Development of the human body_sentence_8

Prenatal development starts with fertilization and the formation of the zygote, the first stage in embryonic development which continues in fetal development until birth. Development of the human body_sentence_9

Fertilization Development of the human body_section_1

Main article: Human fertilization Development of the human body_sentence_10

Fertilization occurs when the sperm successfully enters the ovum's membrane. Development of the human body_sentence_11

The chromosomes of the sperm combine with those of the egg to form a single cell, called a zygote, and the germinal stage of embryonic development commences. Development of the human body_sentence_12

The germinal stage refers to the time from fertilization, through the development of the early embryo, up until implantation. Development of the human body_sentence_13

The germinal stage is over at about 10 days of gestation. Development of the human body_sentence_14

The zygote contains a full complement of genetic material, with all the biological characteristics of a single human being, and develops into the embryo. Development of the human body_sentence_15

Briefly, embryonic development have four stages: the morula stage, the blastula stage, the gastrula stage, and the neurula stage. Development of the human body_sentence_16

Prior to implantation, the embryo remains in a protein shell, the zona pellucida, and undergoes a series of rapid mitotic cell divisions called cleavage. Development of the human body_sentence_17

A week after fertilization the embryo still has not grown in size, but hatches from the zona pellucida and adheres to the lining of the mother's uterus. Development of the human body_sentence_18

This induces a decidual reaction, wherein the uterine cells proliferate and surround the embryo thus causing it to become embedded within the uterine tissue. Development of the human body_sentence_19

The embryo, meanwhile, proliferates and develops both into embryonic and extra-embryonic tissue, the latter forming the fetal membranes and the placenta. Development of the human body_sentence_20

In humans, the embryo is referred to as a fetus in the later stages of prenatal development. Development of the human body_sentence_21

The transition from embryo to fetus is arbitrarily defined as occurring 8 weeks after fertilization. Development of the human body_sentence_22

In comparison to the embryo, the fetus has more recognizable external features and a set of progressively developing internal organs. Development of the human body_sentence_23

A nearly identical process occurs in other species. Development of the human body_sentence_24

Embryonic development Development of the human body_section_2

Main article: Human embryonic development Development of the human body_sentence_25

Human embryonic development refers to the development and formation of the human embryo. Development of the human body_sentence_26

It is characterised by the process of cell division and cellular differentiation of the embryo that occurs during the early stages of development. Development of the human body_sentence_27

In biological terms, human development entails growth from a one-celled zygote to an adult human being. Development of the human body_sentence_28

Fertilisation occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). Development of the human body_sentence_29

The genetic material of the sperm and egg then combine to form a single cell called a zygote and the germinal stage of prenatal development commences. Development of the human body_sentence_30

The embryonic stage covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus. Development of the human body_sentence_31

The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus. Development of the human body_sentence_32

The germinal stage takes around 10 days. Development of the human body_sentence_33

During this stage, the zygote begins to divide, in a process called cleavage. Development of the human body_sentence_34

A blastocyst is then formed and implanted in the uterus. Development of the human body_sentence_35

Embryonic development continues with the next stage of gastrulation, when the three germ layers of the embryo form in a process called histogenesis, and the processes of neurulation and organogenesis follow. Development of the human body_sentence_36

In comparison to the embryo, the fetus has more recognizable external features and a more complete set of developing organs. Development of the human body_sentence_37

The entire process of embryonic development involves coordinated spatial and temporal changes in gene expression, cell growth and cellular differentiation. Development of the human body_sentence_38

A nearly identical process occurs in other species, especially among chordates. Development of the human body_sentence_39

Fetal development Development of the human body_section_3

Main article: Fetus Development of the human body_sentence_40

A fetus is a stage in the human development considered to begin nine weeks after fertilization. Development of the human body_sentence_41

In biological terms, however, prenatal development is a continuum, with many defining feature distinguishing an embryo from a fetus. Development of the human body_sentence_42

A fetus is also 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 location. Development of the human body_sentence_43

Maternal influences Development of the human body_section_4

See also: Placenta Development of the human body_sentence_44

The fetus and embryo develop within the uterus, an organ that sits within the pelvis of the mother. Development of the human body_sentence_45

The process the mother experiences whilst carrying the fetus or embryo is referred to as pregnancy. Development of the human body_sentence_46

The placenta connects the developing fetus to the uterine wall to allow nutrient uptake, thermo-regulation, waste elimination, and gas exchange via the mother's blood supply; to fight against internal infection; and to produce hormones which support pregnancy. Development of the human body_sentence_47

The placenta provides oxygen and nutrients to growing fetuses and removes waste products from the fetus's blood. Development of the human body_sentence_48

The placenta attaches to the wall of the uterus, and the fetus's umbilical cord develops from the placenta. Development of the human body_sentence_49

These organs connect the mother and the fetus. Development of the human body_sentence_50

Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development. Development of the human body_sentence_51

The homology of such structures in various viviparous organisms is debatable, and in invertebrates such as Arthropoda, is analogous at best. Development of the human body_sentence_52

After birth Development of the human body_section_5

Infancy and childhood Development of the human body_section_6

Main articles: Infant, Child development, and Child development stages Development of the human body_sentence_53

Childhood is the age span ranging from birth to adolescence. Development of the human body_sentence_54

In developmental psychology, childhood is divided up into the developmental stages of toddlerhood (learning to walk), early childhood (play age), middle childhood (school age), and adolescence (puberty through post-puberty). Development of the human body_sentence_55

Various childhood factors could affect a person's attitude formation. Development of the human body_sentence_56

Development of the human body_unordered_list_0

  • PrepubescenceDevelopment of the human body_item_0_0
    • Neonate (newborn)Development of the human body_item_0_1
    • Infant (baby)Development of the human body_item_0_2
    • ToddlerDevelopment of the human body_item_0_3
    • Play ageDevelopment of the human body_item_0_4
    • Elementary school age, may coincide with preadolescenceDevelopment of the human body_item_0_5

The Tanner stages can be used to approximately judge a child's age based on physical development. Development of the human body_sentence_57

Development of the human body_table_general_0

For North American, Indo-Iranian (India, Iran) and European girlsDevelopment of the human body_header_cell_0_0_0 For North American, Indo-Iranian (India, Iran) and European boysDevelopment of the human body_header_cell_0_0_1
Development of the human body_cell_0_1_0 Development of the human body_cell_0_1_1

Puberty Development of the human body_section_7

Main article: Puberty Development of the human body_sentence_58

Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. Development of the human body_sentence_59

It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. Development of the human body_sentence_60

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. Development of the human body_sentence_61

Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Development of the human body_sentence_62

Until the maturation of their reproductive capabilities, the pre-pubertal physical differences between boys and girls are the external sex organs. Development of the human body_sentence_63

On average, girls begin puberty around ages 10–11 and end puberty around 15–17; boys begin around ages 11–12 and end around 16–17. Development of the human body_sentence_64

The major landmark of puberty for females is menarche, the onset of menstruation, which occurs on average between ages 12 and 13; for males, it is the first ejaculation, which occurs on average at age 13. Development of the human body_sentence_65

In the 21st century, the average age at which children, especially girls, reach puberty is lower compared to the 19th century, when it was 15 for girls and 16 for boys. Development of the human body_sentence_66

This can be due to any number of factors, including improved nutrition resulting in rapid body growth, increased weight and fat deposition, or exposure to endocrine disruptors such as xenoestrogens, which can at times be due to food consumption or other environmental factors. Development of the human body_sentence_67

Puberty which starts earlier than usual is known as precocious puberty, and puberty which starts later than usual is known as delayed puberty. Development of the human body_sentence_68

Notable among the morphologic changes in size, shape, composition, and functioning of the pubertal body, is the development of secondary sex characteristics, the "filling in" of the child's body; from girl to woman, from boy to man. Development of the human body_sentence_69

Adulthood Development of the human body_section_8

Biologically, an adult is a human or other organism that has reached sexual maturity. Development of the human body_sentence_70

In human context, the term adult additionally has meanings associated with social and legal concepts. Development of the human body_sentence_71

In contrast to a "minor", a legal adult is a person who has attained the age of majority and is therefore regarded as independent, self-sufficient, and responsible. Development of the human body_sentence_72

The typical age of attaining adulthood is 18, although definition may vary by legal rights and country. Development of the human body_sentence_73

Human adulthood encompasses psychological adult development. Development of the human body_sentence_74

Definitions of adulthood are often inconsistent and contradictory; a person may be biologically an adult, and have adult behavior but still be treated as a child if they are under the legal age of majority. Development of the human body_sentence_75

Conversely, one may legally be an adult but possess none of the maturity and responsibility that may define an adult, the mental and physical development and maturity of an individual is proven to be greatly influenced by the circumstances in which they exist. Development of the human body_sentence_76

Organ systems Development of the human body_section_9

Development of human organs and organ systems begins in the embryo and continues throughout the human lifespan. Development of the human body_sentence_77

See also Development of the human body_section_10

Development of the human body_unordered_list_1


Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Development of the human body.