The Genetic Counselor

Source: https://www.cdc.gov/genomics/gtesting/genetic_counseling.htm Given the intricate orchestration of gene expression, cell migration, and cell differentiation during prenatal development, it is amazing that the vast majority of newborns are healthy and free of major birth defects. When a woman over 35 is pregnant or intends to become pregnant, or her partner is over 55, or if there … Continue reading The Genetic Counselor

Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles

Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology Not all genetic disorders are inherited in a dominant–recessive pattern. In incomplete dominance, the offspring express a heterozygous phenotype that is intermediate between one parent’s homozygous dominant trait and the other parent’s homozygous recessive trait. An example of this can be seen in snapdragons when red-flowered … Continue reading Other Inheritance Patterns: Incomplete Dominance, Codominance, and Lethal Alleles

X-linked Dominant or Recessive Inheritance

A chart of X-linked dominant inheritance patterns differs depending on whether (a) the father or (b) the mother is affected with the disease. (credit: U.S. National Library of Medicine) OpenStax Anatomy and Physiology An X-linked transmission pattern involves genes located on the X chromosome of the 23rd pair. A male has one X and one … Continue reading X-linked Dominant or Recessive Inheritance

Autosomal Recessive Inheritance

The inheritance pattern of an autosomal recessive disorder with two carrier parents reflects a 3:1 probability of expression among offspring. (credit: U.S. National Library of Medicine) OpenStax Anatomy and Physiology When a genetic disorder is inherited in an autosomal recessive pattern, the disorder corresponds to the recessive phenotype. Heterozygous individuals will not display symptoms of … Continue reading Autosomal Recessive Inheritance

The Autosomal Dominant Inheritance

Inheritance pattern of an autosomal dominant disorder, such as neurofibromatosis, is shown in a Punnett square. Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology In the case of cystic fibrosis, the disorder is recessive to the normal phenotype. However, a genetic abnormality may be dominant to the normal phenotype. When the dominant allele is … Continue reading The Autosomal Dominant Inheritance

Mendel’s Theory of Inheritance

In the formation of gametes, it is equally likely that either one of a pair alleles from one parent will be passed on to the offspring. This figure follows the possible combinations of alleles through two generations following a first-generation cross of homozygous dominant and homozygous recessive parents. The recessive phenotype, which is masked in … Continue reading Mendel’s Theory of Inheritance

What is Apgar Score?

Source: By Madhero88 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10396636 OpenStax Anatomy and Physiology In the minutes following birth, a newborn must undergo dramatic systemic changes to be able to survive outside the womb. An obstetrician, midwife, or nurse can estimate how well a newborn is doing by obtaining an Apgar score. The Apgar score … Continue reading What is Apgar Score?

Adjustments of the Infant at Birth and Postnatal Stages

Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology From a fetal perspective, the process of birth is a crisis. In the womb, the fetus was snuggled in a soft, warm, dark, and quiet world. The placenta provided nutrition and oxygen continuously. Suddenly, the contractions of labor and vaginal childbirth forcibly squeeze the fetus through … Continue reading Adjustments of the Infant at Birth and Postnatal Stages

The Final Stage of Childbirth

Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology The delivery of the placenta and associated membranes, commonly referred to as the afterbirth, marks the final stage of childbirth. After expulsion of the newborn, the myometrium continues to contract. This movement shears the placenta from the back of the uterine wall. It is then easily … Continue reading The Final Stage of Childbirth