The Biological Foundations of Behavior

1. The Biological Foundations of Behavior • The nervous system: the most complicated system in human body where billions of interconnected cells radiate all over the body. • Specialized Cells of nervous system include: 1. Receptor cells: Embedded in sense organs, (seeing – hearing – smelling – tasting – touching). receive various types of stimulation from environment, which are then transmitted to the brain.

2. 2. Effector cells: Brain sends motor signals to the effector cells embedded in muscles and glands. 3. Neurons: Specialized to conduct signals from one part to another, (connect receptor cells to effector cells). 4. Nerve: long, fibrous parts of many neurons bundled together, and run through the bodies.

3. Division of nervous system: • 1- Central Nervous System (CNS): consists of brain and spinal cord. • 2-Peripheral Nervous System (PNS): Branching out from the CNS and leading to all parts of the body. • Neurons from PNS convey signals from receptor cells to the spinal cord and brain (afferent pathway). • Neurons transmit messages from brain and spinal cord to effectors cells (efferent pathway).

4. *Efferent pathway has two divisions: • Somatic nervous system voluntary: control actions that are under voluntary control. • Autonomic nervous system involuntary: control muscles of internal organs ( the heart, intestine, blood vessels) and glands, usually.

5. Autonomic nervous system has two divisions: (opposite effects). a. Sympathetic nervous system: • In emergency situations as meeting a snake, lead to increase blood sugar, heart rate and blood pressure, and inhibiting digestion (Fight- Flight- Fright response)

6. b. Parasympathetic Nervous System: • -Dominates under relaxation conditions and tends to conserve body's energy. • -After eating large meal, it works to aid digestion, at the same time decreasing heart rate and blood flow to skeletal muscles

7. Composition of neuron cell: • A- Cell body: the life support center of the cell. • B- Dendrites: receive messages transmitted from other neurons (antenna of neurons). • C- Axons: carries neural signals to affect the muscle fibers

8. Types of neuron 1- Sensory neurons: carry information form sense organs to the brain & spinal cord. 2-Motor neurons: carry signals from brain and spinal cord to muscles and glands. 3-Inter-neurons: connect neuron to other neurons .

9. Brain • Structurally the brain is divided into the cerebrum, cerebellum, brain stem, and limbic system. (1) Cerebrum (divided into two hemispheres) (2) Cerebellum: center for coordination of movements and postural adjustments.

10. (3) Brain Stem: Includes the midbrain, Pons, and medulla oblongata. • Medulla oblongata: contains vital centers for respiration and cardiovascular functions. (4) Limbic System: located above the brain stem that includes: • The hypothalamus is involved in temperature regulation, appetite control, endocrine function…etc.

11. Neurotransmission: - Neurons communicate information with oneanother by sending electrochemical messages fromneuron to neuron. • Neurotransmitters: - Chemical substances manufactured in the neuron, aid in the transmission of information throughout the body.

12. Major Neurotransmitters in Psychology 1-Dopamine:(excitatory). • Control of complex movements, motivation, and regulation of emotional responses. 2. Epinephrine (adrenaline): • Controls fight-or-flight responsein anxiety disorders.

13. Major Neurotransmitters in Psychology…cot. 3- Nor epinephrine (Noradrenalin) : • plays a role in changes in attention, learning, memory, sleep, wakefulness, and mood regulation 4- Serotonin: (inhibitory): - Control of sleep ,wakefulness, emotions and sexual behavior.

14. Major Neurotransmitters in Psychology…cot. 5- Gamma-Amino Butyric Acid (GABA): - Used in the treatment anxiety and induce sleep. 6- Acetylcholine:(excitatory or inhibitory). • affect the sleep/wake cycle and affect muscles to become active. • 7- Glutamate: the most abundant excitatory neurotransmitter, plays important roles in cognition, learning &memory.