Basic Principles of Evolution through Natural Selection:

• traits are inherited through generations

• characteristics and behaviors that positively impact survival and reproduction are passed on

  • protection against predators

  • increased access to food

  • keep offspring alive

Human Genetics:

Genotype: genetic makeup passed on by biological parents

Phenotype: physical characteristics expressed through genetics

Alleles: specific version of a gene

• Dominant allele: phenotype will be expressed in an individual that possesses the dominant allele

  • cleft chin, double eyelashes

• Recessive allele: will only be expressed if the individual is homozygous for that allele

  • straight hair, green eyes, red hair

Neuron Structure:

• semipermeable membrane: allows smaller molecules and molecules without an electrical charge to pass through

• soma: cell body

• Axon: major extension from the soma

  • coated by myelin sheaths which act as an insulator which increases signal’s travel speed

• dendrites: branches from the some

  • input sites where signals are received from other neurons

• terminal buttons: axon terminal containing synaptic vesicles

  • synaptic vesicles are storage sites for neurotransmitters

  • neurotransmitters are chemical messengers

Action Potential:

• the electrical signal that moves from the cell body down the axons to the terminal buttons

• occurs when threshold of excitation is met

  • all-or-none phenomenon: an incoming signal from another neuron is either sufficient or insufficient to reach threshold of excitation

• from resting potential, neuron receives a signal at dendrites, small pores/gates open on neuronal membrane allowing Na+ ions to move into the cell, causing the internal charge of the cell to become positive, once the threshold of excitation is met, the neuron becomes active and action potential begins

  • when action potential arrives at the terminal button, the synaptic vesicles release neurotransmitters into synaptic cleft, neurotransmitters then bind to receptors on the dendrites of adjacent neurons

    • once the signal is delivered, extra/excess neurotransmitters are broken down or reabsorbed through reuptake

      • reuptake: neurotransmitter gets pumped back into the neuron it was released from to clear the synapse

Neurotransmitters and Drugs:

psychotropics’ interaction with neurotransmitter systems

• restore neurotransmitter balance

  • agonists: mimic neurotransmitters at the receptor

  • Antagonists: block normal activity of neurotransmitters

How do SSRIs operate?

• reuptake prevention

  • reuptake inhibitors prevent the unused neurotransmitters from being transported back to the neuron

    • this allows neurotransmitters to remain active in synaptic cleft longer, increasing their effectiveness

  • SSRI strengthens the effect of serotonin receptors on dendrites for more time

Parts of the Nervous System:

• PNS- Peripheral Nervous System

  • made of body’s nerves

  • carries messages back and forth from the central nervous system and muscles, organs, and senses in the periphery of the body

  • 2 subdivisions; work together to maintain homeostasis

    • Somatic Nervous System: conscious/voluntary activities

      • relay of sensory information to and from CNS

      • consists of motor and sensory neurons

        • motor neurons carry instructions from CNS to muscles making them efferent fibers

        • sensory neurons carry information to the CNS making them afferent fibers

    • Autonomic Nervous System: involuntary activities

      • controls internal organs and glands

        • 2 subdivisions which work together to maintain homeostasis

          • Sympathetic Nervous System: Prepares body for stressful activities

            • dilates pupils and bronchi, inhibits salivation, digestion and, and badder contraction, increases heart rate

            • fight/flight response allows body to access energy reserves and heightened sensory capacity to fight threat or run away

          • Parasympathetic Nervous System: returns body to routine activities after stress

            • constricts pupils, bronchi and bladder, stimulates salivation and digestion, slows heart rate

The Brain and Spinal Cord:

• Forebrain: largest part of the brain, processes information of complex cognitive activities, sensory functions, and voluntary motor activities

• Contains:

  • Cerebral Cortex: Outer surface of the brain, associated with higher levels of processes such as consciousness, thought, emotion, reasoning, language, and memory

    • gyri: patterns of folds or bumps

    • sulci: grooves

    • longitudinal fissure: deep grove that separates the brain into hemispheres

      • two hemispheres are connected by the corpus callosum (200 million axons)

• frontal lobe: forward part of the brain, responsible for reasoning, motor control, emotion ad language

  • motor cortex: planning and coordinating movement

  • prefrontal cortex: higher-level cognitive functioning

  • Broca’s area: language production

• parietal lobe: processes information from body’s senses

  • somatosensory cortex: processes touch across the body

• temporal lobe: side of head (near temples), associated with hearing, memory, emotion, some aspects of language

  • auditory complex: processes auditory information

  • Wernike’s area: speech comprehension

• occipital lobe: back of brain

  • primary visual cortex: interprets visual information

• limbic system: processing emotion and memory

  • hippocampus: learning and memory

  • amygdala: tying emotional meaning to memories

  • hypothalamus: regulates homeostatic processes

    • body temperature, appetite, blood pressure, sexual motivation and behavior

• Midbrain: between forebrain and hindbrain

  • Reticular Formation: regulates sleep/wake cycle, arousal, alertness, motor activity

  • Substantia Nigra: produces dopamine

    • critical for movement

    • associated with mood, reward, and addiction

• Hindbrain: back of head “extension of spinal cord”

  • Medulla: controls automatic processes of autonomic nervous system (breathing, BP, HR)

  • Pons: regulates activity while sleeping

    • connects hindbrain to rest of brain

  • Cerebellum: controls balance, coordination, movement, motor skills

The Endocrine System:

• consists of a series of glands which produce hormones

  • hormones are controlled through interactions between hypothalamus (CNS) and pituitary gland (endocrine system)

• Pituitary Gland: master gland responsible for secreting growth hormone, endorphins (for pain), and other hormones that regulate fluid levels within the body

• Thyroid Gland: regulates metabolism and appetite

  • thyroxine, triiodothyronine

• Adrenal Gland: stress response, increases metabolic activities

  • Epinephrine, norepinephrine

• Pancreas: regulates blood sugar levels

  • insulin, glucagon

• Gonads (testes and ovaries): mediate sexual motivation and behavior, reproduction

  • male hormones: androgens (testosterone)

  • Female hormones: estrogen, progesterone