Genes are sequences of DNA that code for a particular trait. Different versions of a gene are called alleles—sometimes alleles can be classified as dominant or recessive. A dominant allele always results in the dominant phenotype. In order to exhibit a recessive phenotype, an individual must be homozygous for the recessive allele. Genes affect both…

By the end of this section, you will be able to: – Identify the major glands of the endocrine system – Identify the hormones secreted by each gland – Describe each hormone’s role in regulating bodily functions

By the end of this section, you will be able to: – Explain the functions of the spinal cord – Identify the hemispheres and lobes of the brain – Describe the types of techniques available to clinicians and researchers to image or scan the brain

By the end of this section, you will be able to: – Describe the difference between the central and peripheral nervous systems – Explain the difference between the somatic and autonomic nervous systems – Differentiate between the sympathetic and parasympathetic divisions of the autonomic nervous system

By the end of this section, you will be able to: – Identify the basic parts of a neuron – Describe how neurons communicate with each other – Explain how drugs act as agonists or antagonists for a given neurotransmitter system

By the end of this section, you will be able to: – Explain the basic principles of the theory of evolution by natural selection – Describe the differences between genotype and phenotype – Discuss how gene-environment interactions are critical for expression of physical and psychological characteristics