Nervous, Sensory, and
Motor Systems

An overview of animal nervous systems

Sending a Signal through a Neuron

Human Nervous System

Brain Trauma and Neurological Disorders

The nervous system forms a communication and coordination network throughout an animal’s body

Neurons are nerve cells specialized for carrying electrical signals from one part of the body to another

Organization of Nervous Systems

The nervous system of most animals has two main divisions

The central nervous system (CNS)

The peripheral nervous system (PNS)

consists of the brain and spinal cord (in vertebrates脊椎動物)

consists of mostly of nerves that carry signals into and out of the CNS (連接感覺神經元和運動神經元)

three types of neurons

Sensory neurons function in sensory input

Interneurons integrate (整合) information

Motor neurons function in motor output

Effectors perform the body’s responses to motor output

Neurons

Vary widely in shape

Share some common features

Are the functional units of the nervous system

Structure of a motor neuron

Two types of extensions project from the cell body:

Supporting cells (支持細胞)

myelin sheath (神經髓鞘)

synaptic terminal (突觸終端) that relays signals to

Dendrites (樹突)

Axons (觸突)

Receive incoming messages from other cells

Convey the information toward the cell body

transmit signals toward another neuron or toward an effector

Protect, insulate (絕緣), and reinforce (強化) the neurons

Forms an insulating material around an axon

Helps increase the speed of the electrical signal

Another neuron or

An effector (動器細胞)

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Brain Trauma

Neurological Disorders

In 1848, a railroad accident to a man named Phineas Gage

Propelled a three-foot-long spike through his head

Caused significant changes in his personality

Neurological disorders can also affect brain function

Bipolar disorder兩極性情感障礙(躁鬱症) involves extreme mood swings

Alzheimer’s disease causes mental deterioration (退化)

Major depression is extreme and persistent sadness and loss of interest in pleasurable activities.

The Central Nervous System(CNS)

The Peripheral Nervous System(PNS)

Transmit signals that produce responses

Integrate information coming from the senses

Consist of brain and spinal cord

Contain spaces filled with cerebrospinal fluid腦脊髓液 (CSF), a liquid that

Also protecting the brain and spinal cord are layers of connective tissues called meninges(腦膜)

Helps supply the CNS with nutrients, hormones, and white blood cells

Cushions the CNS

The somatic nervous system (體神經系統)

The autonomic nervous system (自主神經系統)

Mainly responds to external stimuli

Carries signals to and from skeletal muscles (骨骼肌)

Regulates the internal environment

Controls

Smooth and cardiac muscles

Organs and glands of the digestive, cardiovascular, excretory(排泄), and endocrine systems

contains two sets of neurons with opposing effects (拮抗方式) on most organs

parasympathetic division (副交感神經系)

sympathetic division (交感神經系)

digesting food and resting

intense, energy-consuming activities (增加身體耗能、應付緊急狀況)

Brain

the most sophisticated computer, consists of

divided into three regions

Up to 100 billion intricately organized neurons

Many more supporting cells

hindbrain (後腦)

midbrain (中腦)

forebrain (前腦)

The Cerebral Cortex (大腦皮層)

The cerebrum consists of right and left cerebral hemispheres (大腦半球) interconnected by the corpus callosum (胼胝體)