Nervous System Notes The nervous system is defined as the biological information highway that is responsible for controlling all biological processes, movement in the body and receives information via chemical signals.
Important Vocabulary Stimulus: any change in the internal or external environment that causes a response For example– slamming book on desk, hot/cold outside Response: change in behavior or function by an organism after being exposed to a stimulus
Important Vocabulary Receptor: tissues specialized to detect stimuli For example-sensory organs (eyes, ear, antennae) and are usually stimulated by taste, touch, smell Effector: cell organelles, tissues or organs that produce responses to stimuli For example– cilia, muscles
Example: If a volleyball is coming toward you The stimulus is the volleyball coming toward you The response is to move/try to catch/avoid The effectors are the muscles used to respond!
What is a Neuron? The functional unit— the nerve cell specifically adapted for transmission of an impulse Nerves: simply a bundle of neurons— insulated from one another and each carrying individual impulses
Types of Neurons 1. Sensory– Transmit impulses from receptors to the brain and spinal cord Include eyes, ears, tongue, nose, and skin 2. Motor- transmit impulses from central nervous system to effectors 3. Interneuron– relay nerve impulses between sensory and motor neurons
The Central Nervous System Brain and Spinal Cord
The Brain Facts: Is part of the central nervous system Only about 3 pounds and is 85% water!!! Contains more than 100 BILLION nerve cells Located in the cranium—protection
Cerebrum voluntary activities sensory areas—receives and interprets data from your skin, eyes, ear, tongue, etc. memory, learning, thought, habits (even the bad ones)
Cerebellum walking, running, throwing, writing balance coordination of motor activities walking, running, throwing, writing balance
Medulla breathing heartbeat coughing sneezing * controls involuntary activities for example breathing heartbeat coughing sneezing
Central Nervous System Z - Cerebrum Y - Cerebellum W - Medulla X – Spinal Cord
The Parts of the Brain
The spinal cord coordinated activities between the brain and other body functions. The spinal cord is also the center for reflex reactions. Reflex examples: knee jerk, blinking flinching coughing/sneezing dilation of pupils
Reflex arc A reflex is an inborn, automatic, involuntary response to stimuli Reflex arc : a pathway over which nerve impulses travel in a reflex.
Receptor Effector
Central Consists of the brain, and the spinal cord Function is to relay messages and process information
associated cells that are not part of the brain or spinal cord Peripheral Consists of nerves and associated cells that are not part of the brain or spinal cord Divided into the sensory and motor neurons Motor– impulses from CNS to muscles or glands Sensory– impulses from senses to CNS
Malfunctions 1. Cerebral Palsy: disturbance of motor functions 2. Meningitis– inflammation of meninges of the brain/spinal cord
Malfunctions 3. Stroke– Cerebral hemorrhage– robs brain of oxygen due to a blood clot 4. Polio– viral disease that affects the brain and NS
Malfunctions 5. Encephalitis– inflammation of the brain