Biology and Behavior. Mod #3 Neural and Hormonal Systems. In 1800, Franz Gall suggested that bumps of the skull represented mental abilities. His theory, though incorrect, nevertheless proposed that different mental abilities were modular. History of Mind. Phrenology. Bettman/ Corbis.
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Neural and Hormonal Systems
A nerve cell, or a neuron, consists of many different parts.
1. Sensory Neurons: receive signals from outside nervous system
2. Motor Neurons: transmit signals to muscles
3. Interneurons: communicate with each other
called dentrites, and a long wirelike axon. The dendrites carry
the signal toward the cell body, while the axon carries it away.
A bundle of neurons is a nerve. Nerves are the body’s wiring. Nerves branch out from the brain and spinal cord to eyes, ears, stomach, skin, bones, and teeth. The tickest nerves look like
pieces of white rope.
Click below to see how a neuron works:
A neural impulse. A brief electrical charge that travels down an axon and is generated by the movement of positively charged atoms in and out of channels in the axon’s membrane.
This is how the electrical activity in an activated neuron looks and sounds!
Threshold:Each neuron receives excitatory and inhibitory signals from many neurons. When the excitatory signals minus the inhibitory signals exceed a minimum intensity (threshold) the neuron fires an action potential.
I can’t take it any-
more. I’ve reached
31 pair of spinal nerves
33 vertebre bones
thousands of neurons -
sensory and motor
Not enough = depression
Not enough = Parkinson’s disease
Not enough = seizures, tremors, insomnia
(why some people avoid MSG)
Just for fun!
Marijuana and schizophrenia - article
How Neurons Work:
How Neurons Are Affected by:
3. Other Drugs: http://www.pbs.org/wnet/closetohome/science/html/animations.html
Nerves consist of neural “cables” containing many axons. They are part of the peripheral nervous system and connect muscles, glands, and sense organs to the central nervous system.
Sympathetic Nervous System: Division of the ANS that arouses the body, mobilizing its energy in stressful situations.
Parasympathetic Nervous System: Division of the ANS that calms the body, conserving its energy.
Sympathetic NS “Arouses”
Parasympathetic NS “Calms”
(rest and digest)
The Brain and Neural Networks
Interconnected neurons form networks in the brain. Theses networks are complex and modify with growth and experience.
Complex Neural Network
The Spinal Cord and Reflexes
The Endocrine Systemisthe body’s “slow” chemical communication system. Communication is carried out by hormones synthesized by a set of glands.
Hormonesare chemicals synthesized by the endocrine glands that are secreted in the bloodstream. Hormones affect the brain and many other tissues of the body.
Epinephrine (adrenaline) increases heart rate, blood pressure, blood sugar, and feelings of excitement during emergency situations.
Is called the “master gland.” The anterior pituitary lobe releases hormones that regulate other glands. The posterior lobe regulates water and salt balance.
You probably want to know about Oxytocin!
Recent studies have begun to investigate oxytocin'srole
in various behaviors, including orgasm, social recognition,
pair bonding, anxiety, trust, love, and maternal behaviors.
Regulate metabolic and calcium rate.
Adrenal glands consist of the adrenal medulla and the cortex. The medulla secretes hormones (epinephrine and norepinephrine) during stressful and emotional situations, while the adrenal cortex regulates salt and carbohydrate metabolism.
Sex glands are located in different places in men and women. They regulate bodily development and maintain reproductive organs in adults.
Go to the site above to see what happens when the neurons do not communicate effectively.
This is the trailer of a film about how one doctor experimented with L-dopa to treat Parkinson’s disease.
His new treatment was able to break the blood-brain barrier and awaken people who had literally been asleep for 30 years!
You can rent the film to see the whole story.