BIOL 109N 1st Edition Lecture 12Outline of Last Lecture 1. Describe the three kinds of muscles2. List the four traits that all muscle types have in common3. Attachment Outline of Current Lecture 1. Neurons 2. Synapse 3. Neurotransmitters reuptake 4. Roles of different neurotransmitters 5. Health and Issues 6. Central Nervous System 7. Principle regions of the brain Current Lecture1. Neurons – have dendrites, a cell body, and an Axon - Dendrites receive information from other neurons or from the environment- The cell body controls the cells’ metabolic activities. - The cell body integrate input from other neurons- An axon conducts the nerve impulse away from the cell body- Axon ending releases chemical called neurotransmitters that affect the activity of nearby neurons or an effector (muscle or gland) 2. Synapse: - junction between a neuron and another cell. This is how neurons communicate by releasing chemicals- Presynaptic neurons – the nerve impulse travels along the axon and reached the synaptic knob (terminal) of the presynaptic- Synaptic vesicles release neurotransmitter into the synaptic cleft - Calcium ions move into the synaptic knob, which releases the neurotransmitter into the synaptic cleft. Neurotransmitter diffuses across synaptic cleft and binds with These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.receptors on the membrane of the postsynaptic neuron causing an ion channel to open. 3. Neurotransmitter Reuptake- 3 fates of neurotransmitters: I. Bind to post synaptic neuronII. Transported back into pre-synaptic neuronIII. Transported into surrounding glial cells4. Roles of Different Neurotransmitters- In the CNS, different neurotransmitters are associated with different behavioral systemsI. Norepinephrine – regulate mood, hunger, thirst, and sex driveII. Serotonin – promoted a feeling of well-being III. Dopamine – regulated emotions and complex movements 5. Health issues: Disease- Changes in the levels of neurotransmitters cause disorders I. Alzheimer’s disease- associated with decreased levels of acetylcholine II. Clinical depression – associated with decrease levels of serotonin, dopamine, andnorepinephrineIII. Parkinson’s disease- associated with decreased levels of dopamineCentral Nervous System I. The cerebrum – consists of the outer layer called cerebral cortex- Consists of gray matter: made of neuroglia interneurons, cell bodies, and unmyelinated axons that integrate information - The underlying white matter- made of myelinated axons and allows for communication between various areas of the brain II. The cerebrum – the corpus callosum is a band of white matter that allows communication between the cerebral hemisphere. - Gray matter – consists of interneurons, cell bodies, and unmyelinated axons- White matter- consists of myelinated axons that allow communication over long distance - The brain: Sulci (grooves) & Gyri (bumps)- allows the brain to fit in the skull, created the compact ability- Two hemispheres are connected by the longitudinal fissure- Grooves on the surface of the brain mark the boundaries of four lobes on each hemisphere: frontal, parietal, occipital, temporal - Three types of functional areas are in the cerebral cortex:  Sensory Area  The primary somatosensory area receives sensory information from the body Motor The primary motor area controls the skeletal muscles Association  Association areas communicate with the sensory and motor areas, and with other parts of the brain to analyze and act on sensory Homunculus (little map) a map of the brain based on how sensitive the areas of the body are. 6. Principal regions of the brain: - Forebrain - Cerebral cortex – involves in abstract thought, problem solving- Thalamus- serves as the relay station of the brain for all sensory information except smell - Hypothalamus- maintains homeostasis by regulating blood pressure, heart rate, breathing, digestion and body temperature. Serves as “master biological clock”- The cerebellum (little brain) – integrates information from the motor cortex and sensory pathways to produce smooth, well-timed voluntary movements. Stores memories of learned motor skills - The brain Stem - Contains reflex centers to regulate the rhythm of breathing, force and rate of the heartbeat, and blood pressure- Serves as the pathway for all sensory messages to the higher brain centers and motor messages to the higher brain centers and motor messages leaving the brain7. The spinal cord: Information highway- Conducts messages between the brain and the body - Serves as a reflex center. A reflex action is an automatic response to a stimulus in a pre-wired circuit called a reflex arc- Spinal reflexes are essentially decisions made by the spinal cord that are beneficial when a speedy reaction is important to a person’ safety 8. The peripheral Nervous system - Consists of spinal nerves and cranial nerves - The body has 31 pairs of spinal nerves, each of which originated in the spinal cord and services a specific region of the body- All spinal nerves carry both sensory and motor fibers - Cranial nerves – the body has 12 pairs of cranial nerves, which arise from the brain/ brainstem and innervate the structures of the head and certain body parts, including the heart and the diaphragm- Some cranial nerves carry only sensory fibers, other carry only motor fibers, and others carry both types of