Nervous System

• The Nervous system is made up of the Central and Peripheral nervous systems
• The Central Nervous system is made up of the spinal cord, brain stem, and brain
• The Peripheral nervous system is made up of the Autonomic and Somatic nervous systems
• The Peripheral nervous system connects the brain and spinal cord to the rest of the body & external environment
• The Somatic nervous system transmits information from the senses to the CNS, and transmits information from the CNS to direct movement of mucles
• The Autonomic nervous system is made up of the Sympathetic and Parasympathetic nervous systems
• The Sympathetic nervous system is the fight or flight response, as it stimulates functions
• The Parasympathetic nervous system calms & conserved energy by slowing functions
• The Autonomic nervous system transmits information to & from internal body organs
• The Sympathetic & Parasympathetic nervous systems are antagonistic as they work in opposition to each other
• The Sympathomedullary Pathway deals with acute (short-term/intermediate) stressors e.g personal attack
• The Pituitary-Adrenal System deals with chronic (long-term) stressors e.g school
• The Pineal gland is an endocrine gland that produces melatonin which affects the sleep-wake cycle
• The Adrenal Medulla produces Adrenaline & Noradrenaline causes the fight-or-flight response
• The Adrenal Cortex produces corticosteroids which trigger the release of glucose & fats
• The Endocrine & Nervous systems work together to produce the acute stress response
• Acute Stress Response: SNS in hypothalamus triggers Sympathetic Adrenal Medulla to produce Adrenaline which causes Fight-or-flight response (increased heart rate & blood pressure, dry mouth, paused digestion)
• The Pituitary Gland controls the release of hormones from all other endocrine glands
• Hormones are secreted into the bloodstream and affect any cell in the body with a receptor to that hormone
• Neurons provide the nervous system with a means of communication by transmitting signals electrically & chemically
• 80% of neurons are located in the brain
• Dendrites recieve messages from other cells
• The Axon passes messages away from the cell body to other neurons, muscles or glands
• The Myelin Sheath is a fatty substance that covers the axon of some neurons and helps to speed neural impulses
• Terminal Branches form junctions with other cells
• Sensory neurons carry messages from the Peripheral to the Central NS
• Relay neurons connect sensory neurons to the motor or other relay neurons
• Motor neurons connect the CNS to effectors e.g muscles & glands
• Sensory neurons have long dendrites and short axons
• Relay neurons have short dendrites and short axons
• Motor neurons have short dendrites and long axons
• A Synapse is the gap between neurons where neurotransmitters are sent over
• Action potential is the electrical signal causing synaptic transmission
• Synaptic vesicles are released from the axon
• Synaptic vesicles release neurotransmitters into the synapse
• Inhibition is when there are more negatively charged neurotransmitters so it is less likely that the signal will be passed on
• Excitation is when there are more positively charged neurotransmitters so the signal is more likely to be passed on
• Summation is when there is an equal number of excitatory and inhibitory neurotransmitters
• During the fight or flight response the pupils dilate to let in more light to allow better vision
• The Adrenal gland is stimulated by the hormone ACTH to produce cortisol in response to stress