Nervous System

2 Main Parts:

CENTRAL NERVOUS SYSTEM

Brain• It is one of the

largest organs in the body, and coordinates most body activities.

• It is the center for all thought, memory, judgment, and emotion.

Parts of the Brain

CEREBRUM

CEREBELLUM BRAIN STEM

• The outer layer of the cerebrum is the cerebral cortex, which is composed of folds of gray matter.

• The cerebrum is subdivided into the left and right halves called cerebral hemispheres. Each hemisphere has 4 lobes.

CerebrumIt is the largest section of the brain.

Lobes of CerebrumMost anterior portion of the

cerebrum, controls motor function, personality, and

speech

The most superior portion of the cerebrum, receives

and interprets nerve impulses from sensory

receptors and interprets language

The left and right lateral portion of the cerebrum,

controls hearing and smell

The most posterior portion of the cerebrum, controls vision.

Parts of the Brain

CEREBRUM

CEREBELLUM BRAIN STEM

coordinates voluntary

movements such as posture, balance,

coordination, and speech, resulting in smooth and

balanced muscular activity.

Can control the balance, emotions, and ability to learn

things.

CEREBELLUMCEREBELLUM

Parts of the Brain

CEREBRUM

CEREBELLUM BRAIN STEM

BRAIN STEM-acts as a pathway for impulses to be conducted between the

brain and the spinal cord.

-means bridge—connects the cerebellum to the rest of the brain.

-most inferior positioned portion of the brain; it connects the brain to the spinal cord.

-it plays an important role in the regulation of cardiac and respiratory function, consciousness, and the sleep cycle.

• is along tube like structure which extends from the brain. The spinal cord is composed of a series of 31 segments. A pair of spinal nerves comes out of each segment. The region of the spinal cord from which a pair of spinal nerves originates is called the spinal segment. Both motor and sensory nerves are located in the spinal cord.

• The spinal cord is consists of the internal gray matter that has the shape of the letter H and surrounded by an external white matter.

Spinal Cord

four regionsFUNCTION:The spinal cord is the main pathway for information connecting the brain and the peripheral nervous system .

Peripheral Nervous System

Two Function:

SENSORY (AFFERENT)

NERVES

MOTOR (EFFERENT)

NERVES

• Nerves

NERVE CELL

• Neurotransmitters are the chemical messengers of the brain, and are used to transmit signals from one neuron to another. This is because neurons don’t actually touch each other- they have a gap between them called a synapse or synaptic cleft. When an action potential reaches the presynaptic terminal (the terminal button before the synapse) it stimulates the release of neurotransmitters into the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic cell (the dendrite of another neuron, on the other side of the synapse). When it binds to the receptor, it will either produce an effect or will inhibit the effect in the postsynaptic cell.

Two Function:

SENSORY (AFFERENT)

NERVES

MOTOR (EFFERENT)

NERVES

• somatic nervous system (SNS)

•autonomic nervous

system (ANS)

Somatic Nervous System• It is Voluntary movement, that we can control. After

the brain has processed the information, the somatic motor neurons respond. Some somatic nerves are used in reflex arcs and are not under our conscious control.

• The primary role of the somatic nervous system is to connect the central nervous system to the organs, muscles, and skin. This allows you to perform complex movements and behaviors.

• Examples: dancing or video games

-Has many Nerves

Two Function:

SENSORY (AFFERENT)

NERVES

MOTOR (EFFERENT)

NERVES

• somatic nervous system (SNS)

•autonomic nervous

system (ANS)

Autonomic Nervous System• We do not control the ANS, therefore, it is said to

be under involuntary control. The ANS allows for homeostasis to occur. These nerves have opposite effects on the organs they control, one nerve will speed up the heart and another will slow it down It is not on and off, it is more like gas and brake.

• regulates the functions of our internal organs (the viscera) such as the heart, stomach and intestines.

• Two Division:

PARASYMPATHETIC ANDSYMPATHETIC DIVISION

Prepares the body for stressful situations—fight or flight– Rest and Digest

• The number of cells in the human body exceeds the number of stars in the milky way

• 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

• By the time it’s born a baby’s brain consists of about 10 million nerve cells

• The nervous system can transmit impulses at a tremendous speed of 100 meters per second

your brain changes and adapts all the time and all through your life

your brain learns and forms memories by strengthening synapses that are used a lot and weakening those that are used less often

What happens as our brains mature?