Nervous System Flashcards
Nervous System
The nervous system coordinates and rapidly responds to external and internal stimuli. The nervous system is responsible for much of the communication between body systems. The nervous system receives and stores information from the outside world and uses it for future application. It also coordinates messages from internal body systems enabling the body to readjust constantly to changing internal and external environments.
The basic functions of the nervous system are to receive sensory input, integrate and interpret stimuli, and respond to stimuli.
Function: Communication
monitors impressions and information from external stimuli and information from internal stimuli. Responds to danger, pain, internal and external changes, and conscious decisions and thoughts. Helps maintain homeostasis, coordinates processing of new learning, stores and retrieves memories, and facilitates judgement, reasoning, and decision making.
Function: Control
directs all body activities, maintains blood pressure, respiration, and other vital functions, regulates body systems with endocrine system, coordinates reflexes, controls instinctual behaviors, stores unconscious thoughts, and controls conscious movements and activities. Stores unconscious thoughts.
Structures of the nervous system
Neurons
- Axon - Myelin sheath - Dendrites
Neuroglia
Neurons
make up a never
Axon
extension that carries impulses away from the neuron
Myelin Sheath
electrically and chemically carries signal from one nerve to another. insulates one cell from another.
Dendrites
a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body
Neuroglia
framework or structure that nerves sit in. the connective tissue of the nervous system, consisting of several different types of cell associated with neurons.
Organs of the nervous system
Brain
- Cerebrum
- Lobes
* Frontal
* Parietal
* Temporal
* Occipital - Cerebellum - Brainstem
Spinal Cord
is the major communication pathway and the brain interprets the information and directs body responses.
Brain
Contains approximately 100 billion neurons and requires approximately 20% of the body’s circulating blood flow. The brain requires a constant flow of oxygen and nutrients and is sensitive to toxins and poisons. Loss of blood flow for 10 minutes causes unconsciousness. The brain’s major divisions are the cerebrum, cerebellum, and medulla.
Cerebrum
composes 80% of the brains volume. Called the “seat of consciousness” since it coordinates sensory data, motor functions, governs intelligence, reasoning, learning, memory, and other complex behaviors. Cerebrum is divided into two layers and two halves. The cerebral cortex composes of the outer layer and consists of gray matter (nerve cell bodies) and the inner layer consists of white matter (myelinated axons). The two halves are divided into hemispheres.
Lobes
cerebral cortex is divided into four lobes.
Frontal Lobe
large and contains the areas for written and motor speech. Largely responsible for the ability of humans to achieve higher levels of mental functioning, conception, judgement, abstract reasoning, social behavior, speech, communication, and is involved in motor functions.
Parietal lobe
sensory area is located in the lobe. Sensations such as touch, taste, pressure, temperature, and pain are received from the skin and interpreted. The ability to recognize shapes and sizes (spatial ability) is also located in the parietal lobe.
Temporal lobe
receives and interprets auditory signals, processes language, controls sensation of hearing, auditory interpretation, and smell. Memories are also stored in the temporal lobe.
Occipital lobe
visual transmissions and interpretation occur in this lobe.
Cerebellum
second largest portion of the brain that also has two hemispheres. Its functions are connected with movement, muscle tone, coordination, posture, and equilibrium. It coordinates the actions of voluntary muscles and adjusts to impulses from proprioceptors (balance) within muscles, joints, and sense organs.
Brainstem
smallest portion of the brain, continuous with the spinal cord. The brainstem serves as the reflex center and controls vital body functions such as heart rate, breathing, reflexes, swallowing, coughing, sneezing, hiccupping, and vomiting.
Spinal Cord (Definition)
Long mass of nerve cells and fibers. Spinal cord has two main functions: to conduct impulses to the brain and from the brain and to act as a reflex center.
Reflex center receives and instantly sends messages through nerve fibers without entering the brain.
Neurotransmitters
a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.
Synage
gap between neurons
