Erstellt von Megan Robinson
vor fast 7 Jahre
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Frage | Antworten |
When does development begin? | Traditionally at BIRTH more recently IN THE WOMB some argue BEFORE CONCEPTION |
What is the Germinal stage? | when the sperm and the egg unite in the fallopian tube to form the zygote |
What is a zygote? | 23 chromosomes from the sperm and 23 from the ovum = 46 chromosomes |
what are the structures in the nucleus called? | chromosomes |
what do chromosomes do? | they store and transmit genetic information |
what are chromosomes made up of? | DNA |
what is different between the first 22 pairs of chromosomes and the 23rd pair? | the first 22 are matching autosomes and the 23rd pair are sex chromosomes |
what does XX and XY chromosomes mean? | XX= GIRL XY= BOY |
what does identical and fraternal mean? | Indentical= monozygotic twins Fraternal= dizygotic twins |
what are the weeks of each of the trimesters? | First Trimester- 1-12 Second Trimester- 13-25 Third Trimester- 26-38 |
when does the foetus reach the age or viability? | during the third trimester, about 22-26 weeks |
what is the zygotic stage? | - weeks 1-2 (1st trimester) - zygote multiples as it travels along the fallopian tube - after 3 days it has became a mass of cells called blastocyst - implantation occurs after 7-9 days - finds food and shelter in the uterus |
what happens int he embryonic stage? | weeks 3-4 - ectoderm: nervous system and skin - mesoderm- muscles, skeleton and circulatory system and organs - endoderm- digestive system, lungs, urinary tract and glands |
what happens in the embryonic stage? | weeks 5-8 - eyes, ears, nose and neck form. arms legs fingers and toes as well as development of the system |
what happens in the foetal stage? | weeks 9-12 organs connect foetus moves genitals form |
what happens in the second trimester? | weeks 13-24 - mother feels movement - well developed organs and brain development -irritated by night and sound |
what happens in the third trimester? | 22-26 weeks - brain development - rhythmic alterations in heart rate associated with periods of awakedness - greater responsiveness (part rate changes to voices) |
describe teratogen | environmental agent that causes damagee during prenatal period |
what are some factors associated with teratogens? | dosage heritability other negative contributing factors age of the organism (sensitive periods) |
what can usage of prescription and non prescription drugs do to a developing baby? | Thalidomide DES (diethylstilbestrol) Accutane |
give some examples of prescription and non prescription drugs | aspirin caffeine anti-depressants |
what can smoking tobacco do to a developing foetus? | -low birth weight, prematurity, impaired heart rate and breathing, death, asthma in later childhood - less attentive to sounds, tension in the muscles, be more excitable and suffer from colic - passive smoking can also lead to similar developmental issues |
what are some illegal drugs? | cocaine heroin marijuana |
what can alcohol exposure in the wombb lead to? | CNS damage FAS, FAE, ARND low IQ health problems slowed growth |
what different maternal diseases are there that effect the foetus? | Rubella HIV Gestational diabetes mellitus |
what is Zika? | transmitted by mosquitos sexually transmitted causes microcephaly miscarriages unknown as to which part of the pregnancy that the consequences are the greatest |
what other maternal factors can cause difficulties throughout pregnancies | age (over 50) nutrition exercise |
what effects can radiation have on a foetus? | under developed brains and physical deformities |
what environmental pollutions effect the foetus? | lead- low birth weight, brain damage, physical defects dioxins- immune system, brain damage mercury in water- brain damage |
what does emotional stress do to the foetus? | intense anxiety- higher rate of miscarriage, premature birth, low birth weight, respiratory and digestive illnesses, sleep disturbances, irritability during first 3 years - low concentration of cortisol leads to reduced physiological capacity to cope with stress |
summarise teratogens | First term- congenital malformations second and third trimester- affects growth, foetal development and foetal tissue near term- adverse effects on abut or neonate after delivery |
what are the environmental factors that can harm the foetus? | dosage heredity poor diet, other teratogens age/sensitive period |
EXAM QUESTION | Discuss the effects of three teratogens on prenatal development |
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