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Fetal stage (weeks 9–40)

When the organism is about nine weeks old, the embryo is called a fetus. At this stage, the fetus is about the size of a kidney bean and begins to take on the recognizable form of a human being as the “tail” begins to disappear.

From 9–12 weeks, the sex organs begin to differentiate. At about 16 weeks, the fetus is approximately 4.5 inches long. Fingers and toes are fully developed, and fingerprints are visible. By the time the fetus reaches the sixth month of development (24 weeks), it weighs up to 1.4 pounds. Hearing has developed, so the fetus can respond to sounds. The internal organs, such as the lungs, heart, stomach, and intestines, have formed enough that a fetus born prematurely at this point has a chance to survive outside of the mother’s womb. Throughout the fetal stage the brain continues to grow and develop, nearly doubling in size from weeks 16 to 28. Around 36 weeks, the fetus is almost ready for birth. It weighs about 6 pounds and is about 18.5 inches long, and by week 37 all of the fetus’s organ systems are developed enough that it could survive outside the mother’s uterus without many of the risks associated with premature birth. The fetus continues to gain weight and grow in length until approximately 40 weeks. By then, the fetus has very little room to move around and birth becomes imminent. The progression through the stages is shown in [link] .

The growth of a fetus is shown using nine pictures in different stages of development. For each stage, there is a picture of a fetus which gets progressively larger and more mature. The first stage is labeled “9 weeks; fetal stage begins.” The second stage is labeled “12 weeks; sex organs differentiate.” The third stage is labeled “16 weeks; fingers and toes develop.” The fourth stage is labeled “20 weeks; hearing begins.” The fifth stage is labeled “24 weeks; lungs begin to develop.” The sixth stage is labeled “28 weeks; brain grows rapidly.” The seventh stage is labeled “32 weeks; bones fully develop.” The eighth stage is labeled “36 weeks; muscles fully develop.” The ninth stage is labeled “40 weeks; full-term development.”
During the fetal stage, the baby's brain develops and the body adds size and weight, until the fetus reaches full-term development.

Prenatal influences

During each prenatal stage, genetic and environmental factors can affect development. The developing fetus is completely dependent on the mother for life. It is important that the mother takes good care of herself and receives prenatal care    , which is medical care during pregnancy that monitors the health of both the mother and the fetus ( [link] ). According to the National Institutes of Health ([NIH], 2013), routine prenatal care is important because it can reduce the risk of complications to the mother and fetus during pregnancy. In fact, women who are trying to become pregnant or who may become pregnant should discuss pregnancy planning with their doctor. They may be advised, for example, to take a vitamin containing folic acid, which helps prevent certain birth defects, or to monitor aspects of their diet or exercise routines.

A pregnant woman is lying on a table being examined by a doctor. The doctor's hands are on her belly.
A pregnant woman receives an ultrasound as part of her prenatal care. (credit: United States Agency for International Development)

Recall that when the zygote attaches to the wall of the mother’s uterus, the placenta is formed. The placenta provides nourishment and oxygen to the fetus. Most everything the mother ingests, including food, liquid, and even medication, travels through the placenta to the fetus, hence the common phrase “eating for two.” Anything the mother is exposed to in the environment affects the fetus; if the mother is exposed to something harmful, the child can show life-long effects.

Questions & Answers

what are cluster A disease?
Saee Reply
because psychology is a natural science as well as a science. it's a interdisciplinary subject
Kamakshi Reply
yes absolutely we cabt out Psychology completely into science dur to its various measuring aspects
utkarsh
cannot* put*
utkarsh
Assess the relationship between heredity and environment in human development
Newman Reply
जिवन कक्षा विकासाच्या एकूण किती अवस्था आहेत
Digambar Reply
what happened Digambar?
sakshi
?
Reina
Is here anybody exactly awared about the medicine used for the schizophrenia?
Fazil
plz can i know if io psychology in demand ou it's better to continu in human resourses management?
Reina
there are many drugs used to alleviate the symptoms, but none are used for curing the disorder itself.
Rupert
Researchers believe that one important function of sleep is to facilitate learning and memory. How does knowing this help you in your college studies? What changes could you make to your study and sleep habits to maximize your mastery of the material covered in class?
whitecat Reply
Well, for starters, both are entirely different aspect for consideration. As a college student, having an adequate amount of sleep is relatively rare especially on instances where we are totally forced to stay all night (whether for studying or doing academic works).
Rupert
benefits of physcology
Irfan Reply
who define first physcology
Irfan
who define first physcology
Irfan
I think it was either Henry James Or William James are the father of psychology.
James
I haven't read the flash cards and memorized them sense 2015.
James
so iv forgotten some info and some has never left me . I'm very passionate about psychology.
James
I study medical psychology
John
the history of psychology usually traces back to ancient chinese practices. but modern times acknowledge Wilhelm Wundt as the first person to establish a school.of thought in psychology.
Rupert
huh
ANGELICA
is it wrong?
Rupert
please can i know what is the difference about io psychology and human resources managment and which is more in demand ?
Reina Reply
What is psychology
Tayyeba Reply
someone who can observe or understand a person's reactions.
Leanne
It is the scientific study of behavior and mental processes
Enos
Sarah is a 30 year old white female. Her occupation is part time chef. She is recently been divorced and has custody of her three children. She has extreme changes in her mood that began to appear in her 20’s but she never went to see a doctor about them. When family tries to talk to her about her u
Ere Reply
listen very carefully for red flags on both sides
Leanne
what does historical racism mean
Unasumming Reply
Means that racism was present in a group of peoples race in there past and maybe even now. Example is the Native Americans and African Americans also Asian people. Anyone of not caucasian resent. So people who are mixed races also experience rascism.
James
racism meaning I would believe is a negative impact on other separate cultures, causing some serious concerns to the human race.
Leanne
How do counsel someone that is kinda depressed, lonely and stuffs but the person is pushing you away with by saying stuffs you don't like? Your age mate
Ajayi Reply
let them figure themselves out met them come to you and listen more than speak
Jascelyn
don't take anything too personal someone who is depressed has more feelings other than being sad. I have been through it we dont alwaya mean the things we say. just give time and space but be there when they are ready.
Deanna
the person should be first dealt with very patience and understanding.......... person's trust should be won first to treat that kind of state if counsel is the priority..... don't rush small steps will lead to get successful results....... after the patient start trusting you conversate with them.
Amisha
OK..... Thank you very much It makes me look desperate for the person's attention Thanks tho
Ajayi
just let them know even if they aren't ready to tall right now, you will be here for them whenever they are.
Deanna
we need to wait till the stage comes when he/ she is ready at mental level to participate as he is the subject and the core of the part of that particular conscelling session
aaqib
A.Are they saying it in general manner or B.they are saying it cz they know something about you personally If it is A. then remember it's a part of counseling...even if you don't agree with their views..it is theirs.. so don't take it personally
PREETI
if it is B. tell them .. we are here to talk about them not you Also remember people takes time with things.. so it does get difficult at times.. but in counseling it's about them not you. And if it affecting you much .. see why is there .. and try to objective about it OR refer them to someone
PREETI
allow them time to always become comfortable by listening to all sorts of thoughts they all sound scattered but if you ,just let it go until their ready to ask for advice ,my thoughts of counciling would go for a few more sessions of them venting until they've had enough to feel they want geedback
Leanne
what is the trait in the given example?
Maya Reply
what's the given example?
SamieMike
my fat cock
Andrea
o.o u seem like u need to read this txt
SamieMike
learning to understand psychological effects of one's mind thoughts
Leanne
mental state and behavior
Mufakir Reply
Feared ,lethargic, self isolated...
Leanne
because psychology basic is observation asa well as science, so people might skeptical about these two but if we look into it people might notice that it's different because psychology is study about mind and science is study about many thing around us and it's not study about mind clearly.
Karona Reply
empirical method is the method of observation on object rather than do experiment .
Karona
ology is the study of theory .
Karona
psyche means soul as well as butterfly.
Karona
psychology is the the study of mind and behavior
Karona
this is where I'm a little sceptical. we learning psychology based on books. but we ourselves r also human. when we to encounter a real life situation how well can we act accordingly
Aileen
im curious more of myself then others
Aileen
psychology is the scientific study of mind and behavior. scientific mean it's based on observation and experiments. yeah we can observe behavior easily but can't read mind directly that's why we do observe behavior and apply test and therapies to study mind basically we behave according to our mind
Faiza
educates a humans thoughts to expand and explore more of how far a mind will go if allowed
Leanne
wilhelm wundt studied psychology for the purpose of
Rufai Reply
i dont know, all inknow is that he pioneered the practice of introspective and his school of thought aims to study behavior as structured elements
Rupert

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Source:  OpenStax, Psychology. OpenStax CNX. Feb 03, 2015 Download for free at https://legacy.cnx.org/content/col11629/1.5
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