2. Biological Bases of Behavior (Ch 3)

2.1 Endocrine System

  • Introduction
    • Made up of glands located throughout the body that secrete hormones into the bloodstream
    • Hormones are chemical messengers secreted into the bloodstream to regulate bodily functions
    • Processes regulated include metabolism, growth rate, digestion, blood pressure, sexual development and reproduction


  • Pituitary gland


    • Master gland of the endocrine system
    • When activated by hypothalamus activates other glands throughout the body

2.2 Etiology

Image result for etiology

  • Biological explanation for mental disorders within psychology
  • It's basically the roots cause or origins of what mental problems
  • Genetic predisposition and hereditary links
    • schizophrenia
    • alcoholism
    • bipolar disorder
  • Malfunctioning brain chemistry, neuroanatomic pathology

2.3 Functional organization of the nervous system

  • Communication throughout the nervous system takes place via neurons, cells that are highly specialized to receive and transmit information across the body

  • Structure of Neurons


    • Cell body
      • helps keep the cell alive and functioning
    • Dendrites
      • take information in from outside of the cell
    • Axons
      • pass information along to other nerve cells, muscles or glands
    • Myelin sheath
      • covers the axon on some neurons (but not all)
      • accelerates the transmission of information
  • Types of Neurons


    • Sensory/Afferent Neurons
      • take in information from body tissues and sense organs
      • transmit to spinal cord and brain
    • Inter/Association Neurons
      • neurons that communicate with other neurons
      • Most common
    • Motor/Efferent Neurons
      • send information from spinal cord and brain
      • to body tissue, muscles, and sense organs
  • Neurotransmitter

    • Neurons work through use of electrical impulses and neurotransmitters


    • Neurotransmitters are chemical molecules contained in vesicles within the axon terminal

    • Neurotransmitters communicate across the synapse gap (the space between two neurons)

    • Any neurotransmitter left in synaptic gap is broken down or absorbed back into the neuron which is called reuptake

    • Each neurotransmitter affects behavior differently

      • Serotonin: mood, emotional states, sleep
      • Dopamine: attention, movement, pleasure sensations
    • Drugs mimic behavior of neurotransmitter

      • Agonist: increase neural activity flow and effect
      • Antagonist: decrease neural activity and effect
  • Nervous system

    • The nervous system is made up of different divisions that have unique functions

      CNS vs PNS


    • Central nervous system (CNS)

      • includes the brain and spinal cord
      • Suspended in cerebrospinal fluid
      • reflexive behavior
      • Relies on sensory, motor, and interneuron communication
    • Peripheral nervous system connects the brain and spinal cord to the rest of the body

      • Somatic nervous system
        • carries information from muscles, sense organs and skin to the CNS
        • carries messages from CNS to skeletal muscle
      • Autonomic nervous system
        • controls internal environment of the body
        • glands, organs and some muscles
        • sympathetic nervous system prepares you for action
        • parasympathetic nervous system is in operation during states of relaxation

2.4 Genetics

  • Genetics play a large role in how and when learning, growing and development occur
  • Human behavior is a product of genetics and environment
    • nature vs nurture
  • Genes do not determine behavior but can have a significant impact on what we do and why we do it

2.5 Neuroanatomy

Image result for parietal lobes function

  • Introduction

    • Neurons in the brain work together as neural networks
    • Different parts of the brain utilize different functions that influence thoughts, feelings and behaviors
    • Malfunctioning or damage in different areas of the brain impact their designated functions

    Image result for human brain diagram

  • Brainstem

    • where the spinal cord enters the skull and is the oldest part of the brain


  • Cerebellum

    • coordination of voluntary movement


  • Thalamus

    • on top of the brainstem, receives information about taste, touch, sight and hearing

      Image result for thalamus taste touch

  • Reticular formation

    • runs through thalamus and brainstem

    • controls arousal and sleep

    • filters incoming stimuli and sends to other parts of brain

      Image result for Reticular formation

  • Limbic system

    • sits between brainstem and cerebral cortex-more recently evolved part of the brain

    • hippocampus: processes memory

    • amygdala: fear and anger

    • hypothalamus: hunger, thirst, sexual behavior; controls pituitary gland

      Image result for Limbic system hippocampus, amygdala, hypothalamus

  • Cerebral cortex

    • the outer covering of the brain

    • motor, cognitive and sensory processes

    • divided into 2 hemispheres and 4 regions

    • frontal lobes: coordinating movement, higher level functioning and speech

      • Broca’s area
      • Wernicke’s area
    • parietal lobes: sense of touch- hands and feet

    • temporal lobes: hearing

    • occipital lobes: vision

      Image result for cerebral cortex lobes and functions

2.6 Physiological Techniques

  • Physiological techniques are used examine the interrelationship between a person’s brain and their behavior
    • EEG, MRI, FMRI, CAT scan, PET scan


  • The term “etiology” refers to the study of which of the following aspects of an illness?
    • (A) Origins and causes
    • (B) Characteristic symptoms
    • (C) Expected outcome following treatment
    • (D) Frequency of occurrence
    • (E) Level of contagiousness
  • A neuron is said to be polarized when
    • (A) it is in the refractory period
    • (B) it is in a resting state
    • (C) it is about to undergo an action potential
    • (D) the synaptic terminals release chemicals into the synaptic gap
    • (E) chemicals outside the cell body cross the cell membrane
  • How many pairs of chromosomes are contained in most human cells?
    • (A) 7
    • (B) 10
    • (C) 16
    • (D) 23
    • (E) 31
  • The release of a neurotransmitter into the synaptic cleft is caused by which of the following?
    • (A) An extended refractory period
    • (B) An action potential
    • (C) Reuptake of the neurotransmitter
    • (D) Binding of the neurotransmitter to a postsynaptic cell membrane
    • (E) Migration of vesicles into the synaptic cleft

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