Neural and Hormonal Systems PSYCHOLOGY Neural and Hormonal Systems

True or False? A small amount of brain tissue from a person cannot be distinguished from that of a monkey. The human brain produces its own natural opiates. Some one can write but be unable to read. Electrically stimulating a cat’s brain at a certain point can cause the animal to cower in terror in the presence of a small mouse. Some people have had their brain cut in half with no apparent ill effect.

What does your skull tell us about you? Demostration: take your hands and feel your skull/head What do you notice?

Phrenology Franz Gall - phrenologist Not very scientific Bumps on skull reveal mental abilities & character traits Not very scientific However it did highlight the presumed function of specific brain regions

Neural Communication Biological Psychology branch of psychology concerned with the links between biology and behavior some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists

Neuron Neuron a nerve cell the basic building block of the nervous system

Neural Communication Dendrite (listen) Axon (speak) the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body Axon (speak) the extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands

The insulator Myelin [MY-uh-lin] Sheath a layer of fatty cells encasing the fibers of many neurons enables vastly greater transmission speed of neutral impulses

Neuron Axon terminals - where message leaves axon Synaptic gap - space the message jumps across from the axon terminal to the next dentrite

Neural Communication Synapse [SIN-aps] (Sherrington) Neurotransmitters junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron tiny gap at this junction is called the synaptic gap or cleft Neurotransmitters chemical messengers that traverse the synaptic gaps between neurons when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse

Neural Communication

Neural communication How does a neuron fire a message?

Neural Communication Action Potential a neural impulse; a brief electrical charge that travels down an axon Threshold the minimum level of stimulation required to trigger a neural impulse

How does a neuron fire a message? For Action potential a Threshold has to be reach: The + sodium ions (partiers) around the axon have to be excited There has to be more partiers (excitatory) then party poopers (inhibitory) for the message to be sent down the axon

Neural impulse - Action potential Resting potential (polarized neuron; - potassium inside, + sodium outside) Excitatory (+ sodium, partiers - gas pedal) vs Inhibitory (- potassium, party poopers -brake) All or nothing response Reach threshold for action potential Depolarization (+sodium come into the axon) Selectively permeable - gate opens Refractory period (recharging, +sodium move back out)

Neural Communication Cell body end of axon Direction of neural impulse: toward axon terminals

Neural communication Where does a neural impulse begin? Know the order of transmission How does one neuron communicate to another? Be able to explain the process

Neural comm. Know names of neurotransmitters and their functions & malfunctions - see chart in book Should also know whether they inhibit or excite

Neural Communication

Neural Communication Acetylcholine [ah-seat-el-KO-leen] a neurotransmitter that, among its functions, triggers muscle contraction Endorphins [en-DOR-fins] “morphine within” natural, opiate-like neurotransmitters linked to pain control and to pleasure

Agonist vs Antagonist Agonists - excite / mimic Antagonists - inhibit / block

Neural Communication Neurotransmitter Receiving cell molecule membrane Receptor site on receiving neuron Agonist mimics neurotransmitter Antagonist blocks

Reuptake Reuptake - neurotransmitters that don’t get absorbed by the receiving neuron go back to the sending neuron

Neural Communication

Neural Communication Dopamine Pathways Serotonin Pathways

3 kinds of neurons 1. Sensory Neurons 2. Interneurons 3. Motor Neurons neurons that carry incoming information from the sense receptors to the central nervous system 2. Interneurons CNS neurons that internally communicate and intervene between the sensory inputs and motor outputs 3. Motor Neurons carry outgoing information from the CNS to muscles and glands

The Nervous System Nervous System the body’s speedy, electrochemical communication system

The Nervous System Nerves neural “cables” containing many axons part of the peripheral nervous system connect the central nervous system with muscles, glands, and sense organs

The Nervous System Central (brain and spinal cord) Nervous system Autonomic (controls self-regulated action of internal organs and glands) Skeletal (controls voluntary movements of skeletal muscles) Sympathetic (arousing) Parasympathetic (calming) Peripheral

2 parts of nervous system Central Nervous System (CNS) the brain and spinal cord Peripheral Nervous System (PNS) the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

PNS Skeletal or Somatic Nervous System the division of the peripheral nervous system that controls the body’s skeletal muscles

PNS Autonomic Nervous System (think automatic) the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart) a. Sympathetic Nervous System division that arouses the body, mobilizing its energy in stressful situations b. Parasympathetic Nervous System division that calms the body, conserving its energy

The Nervous System

The Nervous System

The Nervous System Reflex a simple, automatic, inborn response to a sensory stimulus Skin receptors Muscle Sensory neuron (incoming information) Motor neuron (outgoing information) Brain Interneuron Spinal cord

Neural Networks Neural Networks interconnected neural cells with experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results computer simulations of neural networks show analogous learning Inputs Outputs Neurons in the brain connect with one another to form networks The brain learns by modifying certain connections in response to feedback

The Endocrine System Endocrine System the body’s “slow” chemical communication system a set of glands that secrete hormones into the bloodstream

Endrocrine system Hormones Slow & long lasting chemical messengers that travel through the blood

Endocrine System Pituitary Gland (the master gland) under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands

Endrocrine system Adrenal [ah-DREEN-el] Glands a pair of endocrine glands just above the kidneys secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress