8th 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 withvisual processing

◦ Temporal-associatedwith processing andrecognition of sounds, memory, andspeech

◦ Activity-Stroop Effect

Brain (cont’d)◦ ventricles: spaces within the cerebrum that

contain a fluid called cerebrospinal fluid (CSF), which flows through the space around the brain and spinal cord

◦ cerebral spinal fluid (CSF): clear, colorless fluid to cushion the brain and spinal column from shock; transports nutrients, and clears metabolic waste

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

◦ Pairs of Spinal Nerves: 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

SomaticVoluntary

AutonomicAutomatic! Involuntary

Voluntary Involuntary

All the actions that we choose to do:

StudyingPracticing SportsSingingWhat else?

All the actions that our brain controls without us knowing:

DigestingBreathingRegulating Body

TemperatureWhat else?

12 pair of cranial nerves31 pair of spinal nerves

Cells of the nervous system are called neurons

13-33 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

A neuron has many of the same organelles such as mitochondria, cytoplasm and a nucleus, as other cells in the body.

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

Head injury Problems with development Damaged or dead nerve cells Loss of blood flow to the brain Cancer Infection

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

www.kidshealth.org Soccer and the brain, Football and the

brain, Skateboarding and Extreme Sports

www.stroke.org Transient Ischemic Attack Cerebrovascular Accident

www.spinalcord.org

www.cdc.gov/meningitis

Avoid tobacco, drug, and alcohol use Drink plenty of water Get sleep! Eat healthy foods Never compromise your breathing Wear helmets when pertinent

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