YIXUAN HE Nervous System

Function Coordinates the voluntary and involuntary actions of the animal and transmits signals between different parts of its body.

Central Nervous System (CNS) The brain and spinal cord

Peripheral Nervous System (PNS) Nerves that connect the CNS with the rest of an animal’s body. Paired cranial and spinal nerves. Motor Nervous System – carries signals to skeletal muscles. (Voluntary system) Autonomic Nervous System – regulates the primarily automatic, visceral functions of smooth and cardiac muscles. (Involuntary system)

Cerebral Hemisphere right and left Each hemisphere consists of outer layer of cerebral cortex, internal white matter and groups of neurons Left: logic, definitions, precise operation.  analyzes, counts, uses language and symbols, knows that time is passing, thinks rational, plans, draws conclusions, does math, it creates arguments, distinguishes single detail Right:  visions, dreams, sees the whole picture, understand metaphors, fantasies and dreams, humor and rhythm, is responsible for moments of revelation

Diencephalon Function:  Directing Sense Impulses Throughout the Body  Autonomic Function Control  Endocrine Function Control  Motor Function Control  Homeostasis  Hearing, Vision, Smell, and Taste  Touch Perception

Brain Stem Connects cerebrum and spinal cord Coordinates motor control signals sent from brain to body Function:  Alertness  Arousal  Breathing  Blood Pressure  Digestion  Heart Rate

Cerebellum responsible for the coordination of movement, balance, equilibrium and muscle tone. controls movement by processing and coordinating sensory input. calculates and corrects informational discrepancies in order to produce the desired movement.

Transmission of Nerve Impulse Polarization Resting Potential Action Potential

1. Polarization Sodium is on the outside, and potassium is on the inside. When a neuron is not stimulated, its membrane is polarized. The outside of the cell contains excess sodium ions (Na+); the inside of the cell contains excess potassium ions (K+).

2. Resting Potential When the neuron is inactive and polarized, it's said to be at its resting potential. It remains this way until a stimulus comes along.

3. Action potential Sodium ions move inside the membrane. When a stimulus reaches a resting neuron, the gated ion channels on the resting neuron's membrane open suddenly and allow the Na+ that was on the outside of the membrane to go rushing into the cell. Neuron goes from being polarized to being depolarized. Threshold level- point at which there is no hold back After more positive ions go charging inside the membrane, the inside becomes positive, as well; polarization is removed and the threshold is reached. After the stimulus goes above the threshold level, more gated ion channels open and allow more Na+ inside the cell.  Causes complete depolarization of the neuron and an action potential is created. In this state, the neuron continues to open Na+ channels all along the membrane. When this occurs, it's an all-or-none phenomenon. "All-or-none" means that if a stimulus doesn't exceed the threshold level and cause all the gates to open, no action potential results; however, after the threshold is crossed, there's no turning back: Complete depolarization occurs and the stimulus will be transmitted.

Refractory Period puts everything back to normal:  Potassium returns inside, sodium returns outside. Na + and K + are returned to their original sides: Na+ on the outside and K+ on the inside. After the Na+/K+ pumps return the ions to their rightful side of the neuron's cell membrane, the neuron is back to its normal polarized state and stays in the resting potential until another impulse comes along.

Neurotransmitters Chemicals that transmit signals from a neuron to a target cell from across a synapse They are released into and diffuse across the synaptic cleft, where they may be accepted by the next neuron at a receptor. IPSP - inhibitory postsynaptic potential  makes a postsynaptic neuron less likely to generate an action potential. EPSP - excitatory postsynaptic potential  makes a postsynaptic neuron more likely to generate an action potential.

Parkinson’s Disease Affects movement; loss of dopamine-producing brain cells Symptoms  Tremor or trembling  Rigidity, or stiffness of the limbs and trunk  Slowness of movement  Postural instability, or impaired balance and coordination. Prevalence  Usually affects those over age 50  Estimated seven to 10 million people worldwide are living with Parkinson's disease. Treatment:  Currently no treatment for PD  Medication can provide relief from symptoms

Sclerosis Caused by damage to the myelin sheath, the protective covering that surrounds nerve cells.  Nerve signals slow down or stop. Prevalence  More common in women  Affects more than 350,000 people in America Symptoms (varies)  Loss of balance or trouble moving  Constipation  Double vision  Muscle spasms  Slurred speech Treatment  No known cure  Therapies may slow the disease

sources National Cancer Institute NINDS  m m NCBI   Cleveland Clinic  logy/multiple_sclerosis/ logy/multiple_sclerosis/ Parkinson’s Disease Foundation  Pictures  