Nervous System

The Nervous System : 

The Nervous System Alaine Davis Woodinville Montessori School

What is the Nervous System? : 

What is the Nervous System? The nervous system consists of the brain, spinal cord, nerves, and sensory system receptors Its roles include taking in sensory input, controlling both voluntary and involuntary muscles, and both conscious and unconscious thought A neuron is a nerve cell, the specialized cell of the nervous system

How long have we known about the nervous system? : 

How long have we known about the nervous system? Some skulls that are at least 10,000 years old have unusual holes in them. Scientists believe that these holes were put there intentionally (a process called trepanning) to "let out the bad spirits.” This implies that these people had some belief that the head or brain had some importance for health and well-being. http://faculty.washington.edu

How long have we known about the nervous system? Part 2 : 

How long have we known about the nervous system? Part 2 The first recorded use of the word "brain" belongs to the ancient Egyptians. The word for "brain" and other "neuro" words appear in the Edwin Smith Surgical Papyrus, which was written by an unknown Egyptian surgeon around 1,700 BC. http://faculty.washington.edu

Divisions of the Nervous System : 

Divisions of the Nervous System Central Nervous System Brain Spinal Cord Peripheral Nervous System Sensory Division Motor Division

CNS: The Brain : 

CNS: The Brain Average adult brain weighs about 3 pounds. (A newborn : less than 1 pound of brain) The brain is made up of 100 billion neurons (It would take you over 3,000 years to count them at a rate of one neuron per second). Neurons are invisibly small; however, the longest neuron in your body is over three feet long! Nerve messages can travel over 250 miles per hour. There is no evidence supporting the myth that we use only 10% of our brain. We use all of our brain!

Lobes of the Brain : 

Lobes of the Brain Frontal lobe Parietal lobe Temporal lobe Occipital lobe

Major Structures of the Brain : 

Major Structures of the Brain Cerebrum Thalamus and hypothalamus Midbrain Pons Medulla oblongata Cerebellum Spinal cord

Structures of the Brain : 

Structures of the Brain Brainstem Lower section of brain includes medulla oblongata, pons, midbrain Regulates sleep, breathing, filters input from senses Cerebellum Coordinates unconscious body movements Cerebellum and brainstem together are sometimes called the “reptilian brain”

Structures of the Brain : 

Structures of the Brain Thalamus Regulates motor and sensory input to the cerebral cortex Hypothalamus Regulates hunger, thirst, body temperature and emotions Hippocampus Seahorse-shaped structure; plays important role in memory Cerebrum (cerebral cortex + corpus callosum) largest and most complex part of the brain Language, mathematics, personality, motor functions

Divisions of the Peripheral Nervous System : 

Divisions of the Peripheral Nervous System

Peripheral Nervous System (PNS) : 

Peripheral Nervous System (PNS) Consists of all nerves, sensors and receptors (everything except the brain and spinal cord) Sensory Division receives information from your senses (external environment/somatic) and your internal organs (visceral). Sensory systems will be discussed in more detail later Motor Division carries brain/spinal cord’s response to muscles and glands

Motor Division of the PNS : 

Motor Division of the PNS Autonomic Nervous System (involuntary responses) Sympathetic Division Prepares body to respond to extreme physical or emotional situations or threats Increases heart rate, increases respiration, slows down digestive system aka “fight or flight” response Parasympathetic Division Calms the body and returns it to regular maintenance functions; the opposite of sympathetic effects Somatic Nervous System (voluntary responses)

More Fun Facts : 

More Fun Facts The right side of the brain controls the left side of the body and the left side of the brain controls the right side of the body. This is also true for sensory input. Neurons do not undergo mitosis and cannot replenish themselves when they die 43 pairs of nerves connect the CNS to all parts of the body. 12 pairs connect directly to the brain and the remainder to the spinal cord If a part of the brain is damaged, other parts of the brain can “take over” the functions of the damaged portion