THE NERVOUS SYSTEM Jordan, Nia, Chloe

Introduction to the Nervous System Big Ideas: ROLE: Detects external and internal signals, transmits and integrates information, and produces a response. Evolutionarily, the nervous system has become increasingly present, as well as an increased amount of ganglia, sensory reception, and cephalization Cephalization: concentration of nervous tissue in the anterior region of the organism (brain) Comprised of the Central Nervous System (brain & spine) and the Peripheral Nervous System (nerves & ganglia)

Neurons Three Main Types of Neurons: Sensory Neurons Interneurons Motor Neurons Neurons are highly specialized for the function of conducting impulses

The typical neuron has a cell body, axon, and dendrites Many axons may have a myelin sheath that acts as an electrical insulator Saltatory Conduction: conduction along a myelinated axon can occur quickly because large spaces can be skipped and signals occur only at the Nodes of Ranvier

Sodium-Potassium Pump Resting Potential = -70 mV Negatively charged proteins inside the cell are too large to move through resulting in an overall negative charge Potassium moves out through the channels resulting in more positive external environment. Na/K pumps move sodium out and potassium in

Action Potential Resting State Depolarization Voltage-gated Na+ channels open first and Na+ flows into the cell Rising phase of the action potential the threshold is crossed, and the membrane potential increases to and past zero Falling phase of the action potential voltage-gated Na+ channels become inactivated; voltage-gated K+ channels open, and K+ flows out of the cell Undershoot membrane permeability to K+ is at first higher than at rest, then voltage-gated K+ channels close and resting potential is restored

Interaction With Muscular System

Terms to Know Presynaptic neuron- a neuron from the axon terminal of which an electrical impulse is transmitted across a synaptic cleft to the cell body Vesicles -small vacuoles Calcium-gated channels- is an ion channel which displays selective permeability to calcium ions. Exocytosis - The process by which cells expel substances Postsynaptic neuron- the postsynaptic membrane is the membrane that receives a signal from the presynaptic neuron.

Synapse Transmission of information between neurons occurs across synapses. A chemical synapse is a junction between two nerve cells consisting of a minute gap across which impulses pass by means of a neurotransmitter.

Neurotransmitters Neurotransmitters are chemical messengers that are involved in the transmission across the synapse. A list of some neurotransmitters are: Acetylcholine- is at all the neuromuscular junctions Epinephrine Norepinephrine Dopamine Serotonin GABA

Action potential depolarized the membrane of synaptic terminal, this triggers an influx of Ca2+. That causes synaptic vesicles to fuse with the membrane of the presynaptic neuron. Vesicles release neurotransmitter molecules into the synaptic cleft. Neurotransmitters bind to the receptors of ion channels embedded in the postsynaptic membrane. The synaptic knob membrane contains voltage gated Ca2+ channels, the postsynaptic membrane contains receptor-bearing sodium, Na+ channels, and the fluidity of the membrane allows for the fusion of vesicles.

Terms to Know Central Nervous System: Brain and Spinal chord Peripheral Nervous System: Nerves from senses; Nerves to Muscles White Matter: myelinated neurons Gray Matter: unmyelinated neurons Cerebrospinal Fluid: What the central canal of the spinal cord and the ventricles of the brain are hollow and filled with Acts as Cushion - Provides Nutrients -Removes waste Glia: Have numerous functions including to nourish, support, and regulate neurons. Astrocytes - Ebryonic Radial Glia

Main Parts of the Brain:

Did you know you can survive when part of your brain is destroyed? Notable Individuals: Phineas B. Gage Reported effects on his personality and behavior. Cameron Mott’s Lives with only the left side of her Brain.

Flow Chart

The Organization of the Human Brain

Information processing 1.)The cerebral cortex receives input from sensory organs and somatosensory receptors 2.) Somatosensory receptors provide information about touch, pain, pressure, temperature, and the position of muscles and limbs 3.) The thalamus directs different types of input to distinct locations

The Human Eye Specialized cells in the retina called ganglion cells convert light rays into electrical signals After light strikes the rods and cones they start a chemical reaction that turns the image focused on the retina into electrical impulses that are then sent to the brain through the optic nerve. Rods: shape, Cones: color

The Human Ear Something creates a sound wave The sound wave travels to the ear and is collect by the outer ear and into the ear canal where it meets the eardrum The ear drum vibrates with these sound waves which vibrates tin bones in the ear These bones carry vibrations into the inner ear to a fluid-filled tube called the cochlea. The fluid inside the cochlea vibrates a series of tiny hairs called cilia, which are attached to auditory nerves. The movement of these cilia stimulates the nerve cells, and they send signals to the brain via the auditory nerve. The brain processes these signals into the sounds we hear

Take out your devices for Kahoot. https://play.kahoot.it/#/k/17e8d14a-5e63-4e53-a997-7758402c3a59