neuro-lecture 2
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The document provides an overview of the nervous system, including its central and peripheral components. It describes the structure and function of neurons, how they communicate via electrical signals and neurotransmitters. Several key areas of the brain are examined, such as the cerebral cortex, prefrontal cortex, limbic system, cerebellum, and brain stem. The roles of important neurotransmitters like dopamine and serotonin are also reviewed. The document aims to educate about neuroscience and psychology by exploring the anatomy and physiology of the nervous system.
neuro-lecture 2
- 2. Objectives Gain a general understanding of the nervous system Gain knowledge of the structure and function of the neuron Navigate your way around the major brain areas and understand their function
- 4. Central nervous system Brain ~2% of body weight, uses ~20% of resources Composed of bunches of neurons, which form nerves Spinal cord Complex tangle of nerves that stretch from brain to tailbone Collects & transmits info between brain and peripheral nervous system Also initiates reflexes: automatic responses to an event
- 5. Peripheral Nervous System PNS links the CNS to the organs, muscles, and glands of the body PNS has two parts Somatic (SNS): nerves controlling voluntary muscle movements Autonomic (ANS): controls glands, organs, blood vessels ANS has two parts Sympathetic: arouses body to prepare for action (fight or flight) Parasympathetic: slows down body to reserve energy
- 7. The Neuron All brain activity originates with the neuron The messengers of the brain-world These cells receive signals from neurons or sense organs, process the signals, and send them to other neurons, muscles, or organs Three types Sensory: respond to sensory organ input Motor: send signals to muscles to control movement Interneurons: the go-between of sensory and motor neurons We have about 100 billion neurons Most, but not all, can be re-grown (severe spinal cord injury vs. cutting your finger)
- 8. The Neuron
- 9. The Neuron: Structure Cell body: houses nucleus Cell Membrane: skin of the cell Axon: cable extending from the cell body Impulse from cell body travels along axon to its end, where terminal buttons release neurotransmitters (chemical messengers), received by other neurons Axon is covered by myelin sheath, which is composed of a fatty substance that helps impulses travel the length of the axon Dendrite Branches extending from cell membrane that receive neurotransmitters from other neurons
- 10. The Dendrite Increases receptive surface of the neuron Contacts occur along surface of dendrite
- 11. The Axon Axon hillock Myelin sheath Nodes of Ranvier The points just between the myelin sheaths
- 12. The Neuron in Action When a neuron receives impulses from other neurons, the cell membrane allows open exchange of positively and negatively charged ions Action potential (change in electrical charge) runs down axon to terminal buttons This all starts with the axon hillock – the gatekeeper of the neuron Terminal buttons release neurotransmitters Neurotransmitters cross the synaptic cleft to the dendrite of the receiving neuron
- 13. The Neuron in action
- 14. Communication in the Neuron All-or-nothing The action potential either happens or it doesn’t Non-decremental Action potentials don’t change in amount (voltage) as they travel Refractory period Neurons need 2ms to recover before they can transmit again Threshold The minimum level of stimulation required to trigger a neural impulse Once you reach the threshold, the action potential doesn’t get bigger
- 15. Important Neurotransmitters Acetylcholine (Ach) Slows down the body, memory, and attention (involved in Alzheimer’s disease) Dopamine (DA) Voluntary movement, attention, and learning; high levels are associated w/schizophrenia Endorphin Reduce sensitivity to pain; linked with pleasure (opiate-like) Serotonin Arousal, sleep; Prozac increases levels of serotonin Norepinephrine Helps control alertness and arousal; low levels can depress mood
- 16. History of Studying the Brain Franz Joseph Gall (1758 – 1828) Phrenology The study of the structure of the skull to determine a person’s character and mental capacity 26 ‘organs’ on the surface of the brain
- 17. History of Studying the Brain Phrenological Map of the Skull
- 18. History of Studying the Brain Flourens (1794 – 1867) Emphasized the importance of experimental research of the brain Carefully controlled experiments on animals to determine localities of brain and their functions Moved the field of brain research into a more scientific arena
- 19. Areas of the Brain
- 20. Five Major Brain Areas CEREBRAL CORTEX is involved in your higher mental functions of perceptual awareness, recognition and interpretation of sensory stimuli (mostly based on memories). PREFRONTAL CORTEX is involved in your conscious thinking processes, especially making choices by using your brainpower LIMBIC SYSTEM is involved in the expression of your instincts and feeling processes, including your moods, since it includes your hypothalamus and amygdala parts; CEREBELLUM is involved in your posture and many coordinated movements; BRAINSTEM controls your body's most basic unconscious life- sustaining functions, including your breathing and heartbeat.
- 21. Cerebral Cortex Two halves, four lobes Frontal lobe (seat of intelligence) Motor cortex (walking, chewing) Parietal lobe Sensory cortex Prosopagnosia (face blindness) Unilateral neglect (only realize half) Temporal lobe Auditory areas (opposite ear) Occipital lobe Visual areas (opposite eye)
- 22. Prefrontal Cortex The prefrontal cortex (PFC) is the very front of the brain, located right beneath the forehead. It is in the anterior (front) region of the frontal lobes. It is responsible for the executive functions, which include mediating conflicting thoughts, making choices between right and wrong or good and bad, predicting future events, and governing social control — such as suppressing emotional or sexual urges. The prefrontal cortex is the brain center most strongly implicated in qualities like sentience, human general intelligence, and personality.
- 23. Limbic System Hormonal system* Hypothalamus Feeding Reproductive behavior Temperature Hippocampus Memory Amygdala Feeding Memory Emotion
- 24. Cerebellum The cerebellum (Latin for little brain) is a region of the brain that plays an important role in motor control. It is also involved in some cognitive functions such as attention and language, and probably in some emotional functions such as regulating fear and pleasure responses.
- 25. Brain Mapping How your brain is laid out. Actually, how any animals brain is laid out. Two parts, linked together, but functioning as one unit/different units. Distinct differences between hemispheres. Left handed-ness or right handed-ness.
- 26. Left & Right Functions
- 27. Two Cerebral Hemispheres Contralateral arrangement Corpus callosum Thick band of nerve fibers connecting the hemispheres It’s how the 2 hemispheres communicate Right-brained vs. left-brained? Bicamerialism?? OR
- 28. Brain Stem Region of the brain where the spinal cord enters the skull and swells Medulla Regulates heart-rate, breathing, blood pressure, and motor movements Cerebellum Controls skilled motor movements
- 29. Brain Stem Pons Connects the two hemispheres of the cerebellum Reticular formation Sleep Attention Thalamus Relay center Filters & organizes information from senses
- 30. Preserve Your Brain This is a “normal” brain firing This is a brain that has just done ecstasy