Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Module 3 Neural and Hormonal Systems Action plan • We will follow a bottom-up approach 1. Neurons & their intercommunications (M3) 2. Brain & the nervous sytem (M4) 3. Genetic influences (nature) and Environmental influences (nurture) (M5 & M6) 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. The structure of a neuron Neuron: the building block of the nervous system How do the neurons communicate? 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”. Acetylcholine • involved in muscle contraction, learning and memory • Video about neural communication and acetylcholine Neural communication within the brain Serotonin Pathways Dopamine pathways 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 How do the drugs work? 1. Mimic a natural neurotransmitter (heroin and morphine) 2. Block the reuptake of the neurotransmitter 3. Inhibit release of the neurotransmitter 4. Occupy the receptor sites of a neurotransmitter 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. Dopamine and cocaine • Video The Nervous System 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 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 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 Automatic NS: the Sympathetic System Automatic NS: the Parasympathetic System 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. 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 Feedback system between the nervous and endocrine systems CNS Behavior changed DANGER Pituitary Message to adrenal glands Other glands Hormones Epinephrine is released