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BIO 168
Nervous System part 1
What makes up the nervous system? | Brain & spinal cord, nerves, and receptors |
What two cells make up nervous tissue? | Neurons and neuroglia |
Simple function of neuron? | Intracellular communication |
Simple function of neuroglia? | Essential to function and survival of neuron, preserves structure of neuron |
CNS - Central Nervous System | Brain & Spinal Cord |
PNS - Peripheral Nervous System | Any nervous tissue not in the ENS or CNS |
ENS - Enteric Nervous System | The digestive tract |
CNS sensory experiences do what? | Monitors and reacts to what is going on inside and outside of the body |
CNS motor commands do what? | Controls activities of peripheral effector organs(mainly muscles and glands) |
CNS higher functions are what? | Intelligence, emotion, memory "you" |
What does PNS deliver? | Delivers sensory information to CNS |
What does PNS carry out? | Carries motor commands out to peripheral tissues |
What does PNS use to carry information? | Nerves |
What is afferent division? | Sensory information from organs, body, and senses that is delivered to the CNS |
What is efferent division? | All the motor commands from the CNS delivered to muscles, glands, and tissues |
What is ENS? | A stand alone system with millions of neurons |
What are the two types of nerves in the PNS? | Cranial nerves and Spinal nerves |
How many pairs of cranial nerves are there? | 12 pairs - on each side |
How many pairs of spinal nerves are there? | 31 pairs - on each side |
What is a nerve? | A bundle of axons with connective tissues and blood vessels |
What do nerves do? | Carry sensory information and motor commands |
What division do receptors belong? | Afferent division |
What do receptors do? | Detect tiny changes in internal and external environment and responds to specific stimuli - sensory info to CNS |
What division do effectors belong? | Efferent division |
What do effectors do? | Target organs that respond to motor commands |
What are the two types of efferent divisions? | Somatic Nervous System and Automatic Nervous System |
SNS - Somatic Nervous System | Controls skeletal muscle contractions |
What are voluntary contractions of SNS? | Conscious control ex: Bringing a glass of water to your mouth to drink |
What is a reflex in the SNS? | Unconscious control - involuntary contractions ex: taking hand off hot stove; leg movement when hit on knee |
ANS - Automatic Nervous System | Controls smooth and cardiac muscle, glandular secretions, and adipose(fat) tissue subconsciously also called Visceral Motor System |
How does ANS respond? | With parasympathetic division or sympathetic division |
What is parasympathetic division? | Rest & digest |
What is sympathetic division? | Faint, Flight, or Flight |
Complex functions of neurons? | Send and receive signals, Generate & propagate action potentials, secrete neurotransmitter messages - uses ALOT of ATP for this |
What does a neuron NOT have? | Centrioles; excpet in the nose and hippocampus(smell & memory) |
Without centrioles a neuron CANNOT do what? | Cannot divide - one is all you get |
What does a neuron call body (soma) contain? | Perikaryon, large Nucleus, nucleolus, mitochondria, RER & ribosomes, Nissl bodies, Neurotubules, neurofilaments, neurofibrils |
What is a perikaryon? | Cytoplasm of a neuron |
What do Neurotubules, neurofilaments, neurofibrils do in the neuron? | Give the neuron shape |
What is a nissl body? | Dense areas of RER and ribosomes in perikaryon; the site of protein synthesis |
What is a dendrite? | Short and highly branched processes from the cell body |
What does a dendrite do? | Intracellular communication |
What is a dendritic spine? | Fine processes on dendrites; 80-90% of neuron surface area |
What does a dendritic spine do? | Part of the neuron which receives information from other neurons in the CNS |
What is a Telodendria? | The dendrite branches on the other end of axon; away from the neuron; also called terminal branches |
What is an axon? | A single, long cytoplasmic process. Long part of neuron (can be 3' long) |
What does an axon do? | Propagates electrical signals (action potentials) |
What is axoplasm? | Cytoplasm of axon |
What does axoplasm contain? | neurofibrils, neurotubules, enzymes, and organelles |
What are the 3 structures of an axon? | Axolemma, axon hillock, and initial segment |
What is the axolemma? | The plasma membrane of the axon, covers the axoplasm |
What is an axon hillock? | Thick region that attaches initial segment to cell body |
What is an initial segment? | base of axon; has many voltage-gated channels |
What is an axon terminal? | Tip of telodendria, very end of axon where it synapses |
What is synapse? | Space where a neuron communicates with another cell |
What is axonal transport? | Movement of materials from neuron cell body to axon terminal |
What is anterograde movement? | Movement on neurotubules from neuron cell body to axon terminal |
What is retrograde movement? | Movement on neurotubule from axon terminal to neuron cell body |
What motor protein is used in anterograde? | Kinesin |
What motor protein is used in retrograde | Dynein |
Where are anaxonic neurons found? | Brain and special sense organs |
Where are bipolar neurons found? | Special sense organs (sight, smell, hearing) |
What neuron is rare? | Bipolar neurons; with one axon and one dendrite |
What does a unipolar neuron look like? | Axon and dendrites fused with the cell body to the side |
Most sensory neurons of the PNS are? | Unipolar |
What is the most common neuron of the CNS? | Multipolar neuron |
What does a multipolar neuron look like? | One long axon with one or more dendrites |
What does a multipolar neuron do? | Controls skeletal muscles |
What is a ganglion? | A 'gang" of cell bodies in the PNS |
What do Somatic Sensory Neurons do? | Monitor outside world and conditions |
What do Visceral Sensory Neurons do? | Monitor internal conditions and organ systems |
What are the 3 types of sensory receptors? | Interoceptors, exteroceptors, and proprioceptors |
What do interocepters do? | Monitor internal systems & senses ex: stretch, deep pressure, pain |
What do exteroceptors do? | Monitor external environment & complex senses ex: sight, smell, hearing |
What do proprioceptors do? | Monitor position and movement of skeletal muscles and joints |
What is peripheral automatic ganglia? | Neurons with cell bodies in the ganglia that have a two nerve component (preganglionic and postganglionic nerves) |
What is integration with interneurons? | Between sensory incoming and motor outgoing |