AP PSYCH Unit 3A Biological Basis Of Behavior Neural Processing & The Endocrine System 1. Everything psychological is simultaneously biological 2. What are neurons and how do they communicate? 3. How do neurotransmitters influence behavior? 4. How do drugs and other chemicals affect neurotransmission?
Psychology and Biology Everything psychological is simultaneously biological. Everything going on in our mind coincides with something going in in our body To think, feel, or act without a body would be like running without legs. We are bio-psycho-social systems. Biological, psychological and social systems interact to produce our mind & behavior
Biological Psychology A. Nervous system B. Brain C. Genetics Nature & nurture together We have come a long way in understanding how the brain is related to behavior: Phrenology Biological Psychology links between biology and behavior, between biological activity and psychological events
Neurons Neuron = 1 cell Nerve = a bundle of neurons
3 Main Tasks of Neurons 1. Receive information from the neurons that feed it. 2. Carry information down its length. 3. Pass the information on to the next neuron.
3 Types of Neurons Can be different sizes and shapes, all share similar structure, and function in a similar way. 3 categories based on neuron location and function: 1. Sensory Neurons 2. Motor Neurons 3. Interneurons
Sensory Neurons Sensory neurons: one-way message from the sense organs toward the spinal cord or brain. Communicate all of your sensory experience; including vision, hearing, taste, touch, smell, pain and balance.
Motor neurons one-way messages away from the spinal cord or brain to the muscles, organs and glands. Motor Neurons
Interneurons Sensory & motor neurons do not communicate directly with each other. Instead, they rely on a middleman. Interneurons (the majority of our neurons) relay messages from sensory neurons to other interneurons or motor neurons in complex pathways.
Parts of a Neuron Dendrites receive messages Cell Body (soma) direct activity Axon passage way Myelin Sheath pushes messages / protects Axon Terminal sends info Synapse space between neurons
Dendrites The dendrite, or receiver part of the neuron, accepts most of the incoming messages. Consists of finely branched fibers. Selectively permeable
Axon Axon: neural impulses are sent through the ends In some neurons (brain) axons are very short. In others, like those in the leg, they can reach 3 feet long. (Imagine a basketball attached to a rope 7km long!)
Myelin Sheath The myelin sheath protects the axon and the electric signal that it is carrying Like the plastic coating does on electric cord. If myelin sheath deteriorates - MS
Action Potential Information travels along the axon in the form of an electrical charge called the action potential. The action potential is the fire signal of the neuron and causes neurotransmitters to be released by the terminal buttons.
Action Potential
Refractory Period Between each action potential is brief recharging time: refractory period. After refectory period neuron is capable of another action potential. Analogy: waiting for the flash to recharge on a disposable camera before you can take another picture. Analogy: waiting for toilet to fill with water between flushes
Threshold Neuron receives info from thousands of other neurons Some excitatory (like pushing the gas pedal) Others are inhibitory (like pushing the breaks) If the excitatory signals, minus the inhibitory signals exceed a minimum intensity, called the threshold, then action potential is realized. Analogy: To pull the trigger of a gun, it takes a certain threshold of finger pressure to fully squeeze it and force the trigger to shoot
All or None Response Once the action potential is released, there is no going back. The axon either fires or it does not: all-or-none response. How do we detect a gentle touch from a slap? A strong stimulus, like a slap, can trigger more neurons to fire, more often, but not any stronger. Analogy: Squeezing a trigger harder wont make the bullet go faster.
A Field Trip!!!! Now that we neurons fire we will go look at the neuron models our school has. To do this, we will have to take a field trip. TO THE BATHROOM It just so happens, that toilets are the perfect examples of neurons.
How neurons communicate Neurons use an electro-chemical process to send messages Why electrical? Pushing information through axon is based on process of positive and negative charges of electrical atoms (ions) Potassium (K+), Sodium (Na+), Chloride (Cl-) Why chemical? Neurotransmitters cross synapse: different ones send different impulses and need to find receptors It can either excite (fire) or inhibit (prevent firing) Messages are sent at a speed of 2-200 mph
Depolarization Depolarization is the initial movement of the action potential where the action passes from the resting potential in the cell body into the action potential in the axon.
How Cells Connect Neurons do not actually touch each other to pass on information. The gap between neurons is called the synapse. The synapse acts as an electrical insulator, preventing an electrical charge from racing to the next cell. Neurotransmitters chemicals used in neural communication. If they have the right fit, the transmitters fit into the receptors like a key into a lock.
Neural Communication The chemicals that our bodies produce work as agonists (excite) and antagonists (inhibit). They do this by amplifying or mimicking the sensation of pleasure (agonist), or blocking the absorption of our neurotransmitters (antagonist). Agonist-opiates mimic the high produced naturally Antagonist-botulin blocks ACh (enables muscle action)
Common Neurotransmitters/Functions
A Human Chain of Neurons Now we will do a demonstration that will show how neurons work and travel. Each person needs to stand up and form a conga line
AP PSYCH Unit 3A The Nervous & Endocrine Systems 1. What are the functions of the nervous system s main divisions? 2. Can you remember feeling an extended period of discomfort after some particularly stressful event? How long did those feelings last?
Central Nervous System (CNS) Includes all neurons in brain and spinal cord The Nervous System Peripheral Nervous System (PNS) Neurons (sensory and motor) that run to and from CNS Connects fingers, toes, etc. to spinal cord
The Central Nervous System CNS The Central Nervous System includes the brain and the spinal cord. They are so important to the human body that they are encased in bone for protection- Support for evolutionary psychologists
The Peripheral Nervous System PNS The Peripheral Nervous System contains all of the nerves which feed into the brain and spinal cord.
Somatic Nervous System (SNS) Controls body s skeletal muscles Sends messages back and forth to brain about sense and movement Example: feel a hot stove and pull hand away The Peripheral Nervous System
Autonomic Nervous System (ANS) Regulates activities of vital organs Lungs, stomach, intestines, heart liver, eliminative organs, and reproductive organs We usually cannot voluntarily control these activities Exceptions: hold breath, control blood pressure, blinking, sneezing The Peripheral Nervous System
Now let s think of some memorization techniques for these systems
2 divisions of the ANS: Sympathetic Nervous System Arouses us for defensive action mobilizes energy ( heartbeat, digestion, blood sugar) fight or flight response Parasympathetic Nervous System Calms us down conserves energy ( heartbeat, blood sugar, etc.) The Peripheral Nervous System
Reflexes Our automatic response to stimuli are reflexes. A simple spinal reflex pathway is composed of a single sensory neuron and a single motor neuron, connected through the spine with an interneuron. This type of response does not involve the brain, and is often why we feel our body move before we feel the stimuli A headless body could demonstrate a reflex like that produced when hitting the patellar tendon with a hammer.
The Endocrine System The endocrine system is the body s chemical messenger system, that relies on hormones. It involves the endocrine glands: pituitary, thyroid, parathyroid, adrenals, pancreas, ovaries, and testes. Hormones are chemical messengers used by the endocrine system. Many hormones are also neurotransmitters.
Working with Other Systems Under normal (unaroused) conditions, the endocrine system works in parallel with the parasympatheticnervous system to sustain our basic body processes. In crisis, the endocrine system shifts into a new mode to support the sympatheticnervous system.it releases epinephrine (adrenalin) Triggers the fight or flight response
The Master Gland While the body has many glands which are important, the most important gland is the pituitary gland. Controls all of the responses of the endocrine system The pituitary gland is no larger than a pea, and is located at the base of the brain.
The Endocrine System The body s slow chemical communication system A set of glands that secrete hormones into the bloodstream