Chapter 2: Biological Foundations Flashcards
What are the common problems involving chromosomes?
Inherited disorders and abnormal chromosomes.
What are the aspects of inherited disorders?
Most: recessive alleles ie sickle cell disease (RBC & oxygen transportation) and phenylketonuria (PKU) (liver enzyme for Phe)
Exception: dominant allele ie Huntington’s disease manifest later (after reproduction) (other dominant diseases people die before reproduction so extinct)
What are the aspects of abnormal chromosomes?
Extra or missing chromosomes ie Down syndrome - extra 21st chromosome, (physical & mental abnormalities) Sex chromosome disorders ie Klinefelter’s syndrome (XXY), XYY complement, Turner’s syndrome (X), XXX syndrome.
(Nearly 1/2 all fertilized eggs abort spontaneously due to abnormal autosomes)
How is heredity influenced by the environment?
- Dynamic interaction throughout development (heredity - clay, environment - shaper), ie PKU only cause disease if environment has Phe, menstruation early if environmental stress, also every day biology: change in DNA expression, nutrition parenting, environment
- Genes influence environment ie predisposed intelligence/extroversion may allow for other opportunities or niche-picking
- Environmental influences make children within a family different
What is niche-picking?
When someone deliberately seeks environment compatible with one’s genetic make up
What is ovulation?
Ovulation: an egg cell from the ovary enters the fallopian tube at 9-16 days of menstrual cycle
What are the aspects included in the period of the zygote?
1-2 weeks
conception, implantation, germ disk: cells at center of zygote become baby and other cells become supporting structures, outer layer becoming placenta (4 nutrient exchange)
What are the aspects of conception?
w/i 24 hrs ovulation: usually in upper 1/3 fallopian tube
24-30 hrs: male & female chromosomes unite,
36hrs- 2 cells,
48hrs- 4 cells,
3 days- 16-32 cells,
4 days- 100 cells (hollow ball),
4-5 days zygote enters uterus,
6-7days begin implantation,
12-14 days zygote completely implants
What are the aspects of implantation?
Zygote burrows into uterine wall and connects with mother’s blood taking about one week and causing a hormonal change that stops menstruation
What occurs in the period of the embryo?
Weeks 3-8
Embryo when zygote completely embedded.
- body structures and internal organs develop
- ectoderm: hair, outer skin, nervous system
- mesoderm: muscles, bones, circulatory system
- endoderm: digestive system and lungs
Rests in amnion containing amniotic fluid for cushion and temperature regulation
- placenta and umbilical cord links embryo with mother.
Development according to cephalocaudal and proximodistal principles
What occurs during the period of the fetus?
Weeks 9-38
Baby gets larger and systems begin to work: cerebral cortex, sex organs, and vernix develop. Hart rate can indicate stress.
At 22-28 weeks systems function well enough to live outside of the womb with care “age of viability.” do not have layer of fat for temperature regulation
- Lots of movement, sensory experiences (speech, light)
What about maternal stress?
Greater maternal anxiety is correlated with early and low-weight births and preschoolers with behavioral problems. Increased stress (1) decreases blood flow to fetus, (2) weakens mother’s immune system which can harm development, (3) more likely smoke & drink alcohol & less likely rest, exercise, and eat properly, (4) epigenetic changes affecting genes help children regulate their behavior.
What are teratogens? What impact can they have?
Drugs, diseases, and environmental hazards that cause abnormal prenatal development.
Impact: depends on genotype, changes depending on stage of development, affects a certain aspect of development, depends on dose, may not always be apparent at birth.
What are common drug teratogens?
Nicotine: constricts blood vessels: physical and mental development issues
Alcohol: Fetal alcohol syndrome, slow growth, heart problems, physical and developmental abnormalities.
What are common disease teratogens?
Attack through placenta: cytomegalovirus, rubella, syphilis
Attack during birth: AIDS, genital herpes
- Medication may help mother without helping fetus
