1. Neural and Hormonal Systems
Module 3
Neural and Hormonal Systems
Videos for the lecture:
Show zimbardo #3 – dakika
Neural networks
Cocaine and dopamine
All movements require the brain to send appropriate messages to the muscles and coordinate incoming messages from sensory organs and glands etc.
Such messages --- movement, feeling, thinking – are communicated through specialized cells called neurons – NERVE CELLS
Only type of cells in the body that can communicate –
Basıc elements of the NS –
Almost 1 trilllion on them exist throughout the body controlling our behaviors.

2. Action plan We will follow a bottom-up approach
Neurons & their intercommunications (M3)
Brain & the nervous sytem (M4)
Genetic influences (nature) and Environmental influences (nurture) (M5 & M6)
To understand the biological functions influencing our behaviors, emotions and thoughts, we will follow a bottom- up approach:
First study the building blocks of nervous sytem – then their functions.

3. Body’s communication system: Neural Communication
All movements require the brain to send appropriate messages to the muscles and coordinate incoming messages from sensory organs and glands etc.
Such messages - movement, feelings, thinking – are communicated through specialized cells called neurons. 

4. The structure of a neuron
Neuron: the building block of the nervous system 4

5. How do the neurons communicate?
Each neuron is a decision maker --- communicates with thousands of other neurons (depending on which part of the CNS they are at).
A combination of these impulses
--- either excite (send the message) or
---- inhibit (do nothing – like pushing a brake and not passing along the impulse).
Impulse --- lıke a gun firing. ALL or NONE – once triggered bullet comes out.
But speed and frequency of firing may differ.
Then neurons have to communicate with each other. (kulaktan kulaga)
This is more of a chemical process.
Neurons do not touch each other. There is a small gap – full of fluid. Neurotansmitters – messengers, travel within this gap – in between neurons – from the axons of one to the dendrites of the other.
-- several types of neurotransmitters. Where exactly matters.

6. How do the neurons communicate? Neurotransmitters
Chemical messengers that go across the synaptic gaps between neurons.
They bind to the receptor sites on the receiving neuron
They influence whether the receiving neuron will respond with a “neural impulse”.
NTS come out of axon terminals and fit into receptors on the dendites of the receiving neuron.
They fit like a key fitting in a lock. This starts the electrical charge in the receiving neuron. Excess ampunts of neurotansmitters go back through the synaptic cleft and then are reuptaken – absorbed– by the sending neuron. Many drugs intervene at this stage ---
Show neurotransmitters video
Like a vapur carrying passengers from besiktas to kadikoy--- carry the chemical messengers from one nuron to the neighboring one.
Structure, operation and functions of neurons are fundamnetal biological aspects of the body – that underlie several primary psychological processes.
Our understanding would have been limited if we did not know these.
Within – electric
Between – chemical 6

7. Acetylcholine involved in muscle contraction, learning and memory
Video about neural communication and acetylcholine

8. Neural communication within the brain
Dopamine pathways
Dopamine --- controls movement, attention and learning.
-- deficiency – parkinsons
-- excess --- schizophrenia and other mental disorders.
Serotonin Pathways

9. Neurotransmitters
Acetylcholine: Learning, memory, muscle contraction (Alzheimer’s)
Endorphins: (“morphine within”) pain control and to pleasure
Dopamine: Movement, learning, attention, emotion (Schizophrenia, Parkinson’s)
Serotonin: Mood, hunger, sleep, arousal (depression)
Norepinephrine: alertness and arousal
GABA: Inhibitory (undersupply causes seizures, tremors, insomnia)
Glutamate: Excitatory, memory (oversupply causes seizures, migraines)
Different neurotransmitters have different effects on behavior and emotion. (Influence all motions and emotions. )
-- depends on specific parts of the CNS they are at ---
Later will talk about their role in depression, hunger, memory, thinking, addictions, therapies etc.
BALANACE IS IMPORTANT.
To give an example.
ACh --- one of the best understood chemicals.
Vital in learning and memory
Also release of ACh controls muscle contracts.
If blocked --- mucsles do not contract --- one method used in hunting. – animal becomes paralyzed
For humans – there is a drug called botox that blocks release of ACh? what happens
Paralyzes wrinkles underneath the facial muscles.
Balck widow spider---- poison – causes excessive amounts of ACh to be released--- cannot control muscle contaction and die.
Dopamine ve Seretoninden de bahset. 9

10. How do the drugs work?
Mimic a natural neurotransmitter (heroin and morphine)
Block the reuptake of the neurotransmitter
Inhibit release of the neurotransmitter
Occupy the receptor sites of a neurotransmitter
heroin and morphine brain may stop producing its own endorphins  withdrawal  sensation of pain
E.g., release of acetylcholine, the neurotransmitter found at every junction between a motor neuron and skeletal muscle, causes the muscle to contract. The brain’s endorphins, natural opiates released in response to pain and vigorous exercise, explain the “runner’s high” and the indifference to pain in some injured people.
Some drugs mimic a natural neurotransmitter or may block its reuptake.
Some opiate drugs amplify arousal or pleasure. Other drugs block a neurotransmitter’s effects by inhibiting its release or occupying its receptor site.
Same for alcohol, nicotine, cocaine etc.. Mood altering drugs.
They alter the balance of the nts. İncreased level in the synaptic cleft or prevent reuptake.
During the discovery of the drug morphine --- used to elevate mood and cease pain –
Realized that brain contained receptors for these morphine molecules to lock in. So brain should also have alreasy existing neurotransmitters to fit in these receptors… similar to morphine --- endorphine – natural opiates.
Released in pain and in vigarious exercise.
– explain runner’s high.
---painkilling effects of acupuncture.
-- reaction to pain when severly injured – don’t feel. 10

11. Drug addiction
When the brain is flooded with opiate drugs such as heroin and morphine, it may stop producing its own natural opiates,
Withdrawal of these drugs may result in pain until the brain resumes production of its natural opiates.

12. Dopamine and cocaine
Video

13. The Nervous System 13

14. Neurons of different systems
CNS
Interneurons
CNS’s internal communications
Peripheral system
Sensory neurons
From tissues to CNS
Motor neurons
From the CNS to the tissues 14

15. The Central Nervous System
There exist an intense information network within the brain
40 billion neurons
Each with 10,000 contacts
400 trillion synapses
Organized into neural networks
Spinal cord maintains the communications between the peripheral system and the brain
Reflexes 15

16. The Peripheral Nervous System
Somatic division
Controls voluntary movement
Autonomic division
Controls that parts of the body that keep us alive – the heart, blood vessels, glands, lungs, etc.)
Two parts of the autonomic system
Sympathetic
Acts to prepare the body for action in stressful situations, engaging all the organism’s resources to respond to a threat
Parasympathetic
Acts to calm the body after an emergency or stressful situation has ended
Somatic NS: Controlled behaviors.
Ex: your eye movement in reading this slide.
Automatic NS:
Ex. Hearbeating, blood circulating, digestive etc.
Esp. İmportant in emergencies--- homeostatis

17. Automatic NS: the Sympathetic System17

18. Automatic NS: the Parasympathetic System18

19. The Endocrine System the body’s “slow” chemical communication system
a set of glands that secrete hormones into the bloodstream
Act on brain to influence our growth/ emotions/ motivations/ mood.

20. The Endocrine System: Hormones
Hormones: chemical messengers
manufactured by the endocrine glands
Produced in one tissue and affect another
Pituitary Gland (in the brain)
Controlled by the hypothalamus
regulates growth and controls other endocrine glands
Adrenal Glands
just above the kidneys
secrete epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress . 20

21. Feedback system between the nervous and endocrine systems
CNS
DANGER
Behavior changed
Pituitary
Message to adrenal glands
Other glands
Epinephrine is released
Hormones 21