8 th Grade Science

 The nervous system and the endocrine system regulate and control the activities of the other body systems  The nervous system may be divided into two parts: ◦ central nervous system (CNS): made up of the brain and spinal cord ◦ peripheral nervous system (PNS): made up of cranial and spinal nerves

 The Brain ◦ Cerebrum* ◦ Cerebellum* ◦ Brain Stem* ◦ Medulla Oblongata* ◦ Thalamus** ◦ Hypothalamus** ◦ Midbrain ◦ & MORE!!  The Spinal Cord

 Brain: major portion of the central nervous system ◦ Cerebrum  What we think of as “The Brain”  Largest organ of the nervous system  Consists of two hemispheres: Right and Left

 Brain (cont’d)  Four Lobes ◦ Frontal-associated with reasoning, planning, emotions, problem solving, movement ◦ Parietal-associated with movement, orientation, recognition, perception of stimuli ◦ Occipital-associated with visual processing ◦ Temporal-associated with processing and recognition of sounds, memory, and speech ◦ Activity-Stroop Effect

 Brain (cont’d)  Medulla ◦ Controls involuntary actions ◦ Looks like a swollen lump ◦ Located at top of spinal cord ◦ Inside, two large cords of nerve fibers  One from Left hemisphere  One from Right hemisphere  The cords cross here

 Brain (cont’d)  Each half of the brain interacts with one half of the body  The connections are crossed  Right brain-Left hand; Left brain-Right hand  Left side dominant for language—talking and understanding language  Activity

 Brain (cont’d)  Cerebellum ◦ Means “little brain” ◦ Size of a pear ◦ Located at the rear of cerebrum ◦ Coordinate movements via commands from the cerebrum ◦ Activity: Balancing Act

 Brain (cont’d)  Brain Stem ◦ Located below the cerebrum ◦ Connects the brain with the spinal cord ◦ Sends messages from the brain to the spinal cord ◦ Involved in cardiovascular system control, respiratory control, pain sensitivity control, alertness, awareness, and consciousness

 Spinal cord ◦ Passes through the vertebrae extending from the medulla oblongata to the level of the 2nd lumbar vertebra; conducts nerve impulses to and from the brain and initiates reflex action to sensory information without input from the brain ◦ Responsible for primitive involuntary reactions called reflexes ◦ Cervical (8) ◦ Thoracic (12) ◦ Lumbar (5) ◦ Sacral (5) ◦ Coccygeal (1)

 The nerves outside the brain and spinal cord  Nerve: cordlike structure that carries impulses from one part of the body to another  Connects the Central Nervous System to the rest of the body ◦ Consists of two parts  Somatic Voluntary  Autonomic Automatic! Involuntary

VoluntaryInvoluntary  All the actions that we choose to do: Studying Practicing Sports Singing What else?  All the actions that our brain controls without us knowing: Digesting Breathing Regulating Body Temperature What else?

 Cells of the nervous system are called neurons  Billion Neurons in the brain alone  Parts of a Neuron ◦ Nucleus-stores genetic information ◦ Axon-string like structure that transmits impulses to the next cell ◦ Dendrites-tree like structure that receives impulses from the previous cell ◦ Cell Body-bulbous end that contains the nucleus ◦ Terminal Fibers-the end of the axon ◦ Myelin Sheath-insulation-like covering around axon

 Neuron Model  Yarn Neuron

 Neurotransmitters are chemicals or molecules that help send synapses  Neurons send and receive impulses electrochemically  This is called a synapse: syn=together, haptein=to clasp  Each cubic mm of brain contains roughly a billion synapses

 Synaptic cleft—space between neurons  Axon terminal-part of neuron that sends impulse to the next neuron  Dendrite-part of neuron that receives impulse from the previous neuron

 Tasting and Smelling  Hearing  Touching  Seeing

Medical conditions of the nervous system & how to maintain and promote brain health

 CVA  Ischemic

 6A:6-8 ◦ Like other animals, human beings have body systems for…coordination of body functions ◦ Although social behaviors are affected by both genes and environmental factors, human beings are still able to invent, learn, and modify a wide variety of these behaviors ◦ Interactions among the senses, nerves, and brain make possible the learning that enables human beings to predict, analyze, and respond to changes in their environment