In the fast-paced field of emergency medical services, understanding the language of medicine – particularly the terminology related to the nervous system – can be a lifesaver. This article aims to broaden your knowledge of essential terms associated with neurons, brain structures, nerve types, and common disorders in the nervous system.
Neurons and Their Structures Medical Terms
1. Neuron: The basic unit of the nervous system, which transmits information to other nerve cells, muscle, or gland cells.
2. Dendrites: Branch-like structures of neurons that receive messages from other neurons.
3. Axon: The long, thread-like part of a nerve cell along which impulses are conducted from the cell body to other cells.
4. Synapse: The junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
5. Synaptic Cleft: The space between a neuron’s synapse at the end of the axon and the cell, or minute gap, where neurotransmitters are released and attached to the receiving cell receptor site.
6. Receptor Sites: The structure on a cell that neurotransmitters attach to and cause a reaction that may stimulate or block stimulation of a cell, among other actions. Receptor sites are often made up of proteins and other base molecules.
7. Neurotransmitters: Chemicals released by the axon terminal at the synapse that attaches to receptor sites and communicates an action to another cell.
1. Cerebrum: The largest part of the brain, responsible for all voluntary activities of the body. The cerebrum is made up of regions, or lobes, of the brain that are responsible for different functions.
2. Cerebellum: The part of the brain at the back of the skull, responsible for fine motor control, coordination and balance.
3. Brainstem: The central trunk of the brain, consisting of the medulla oblongata, pons, and midbrain, and continuing downward to form the spinal cord.
4. Meninges: Layers of tissue wrapping around the brain between the brain and the inside of the skull.
5. Brain Hemispheres: The human brain is divided into two distinct halves, known as hemispheres, the left hemisphere and the right hemisphere. They are mirror images of each other in terms of structure but perform different functions, a phenomenon referred to as lateralization of brain function.
The left hemisphere of the brain is traditionally associated with logical abilities such as language, mathematics, and analytic thought. It’s primarily responsible for controlling the right side of the body.
On the other hand, the right hemisphere tends to be more involved with creativity, spatial awareness, artistic and musical abilities, and controls the left side of the body.
Despite this division, the two hemispheres are constantly communicating and sharing information through a thick bundle of nerve fibers called the corpus callosum. This cooperation between the hemispheres is critical for the brain to perform complex tasks and functions efficiently and effectively.
These regions of the cerebrum play an important role in brain function.
1. Frontal Lobe: Located at the front of the brain, the frontal lobe is involved in reasoning, problem-solving, judgment, and motor function. The motor cortex, which directs the body’s voluntary movements, is in this lobe.
2. Parietal Lobe: Positioned at the top of the brain, the parietal lobe processes sensory information it receives from the outside world, mainly relating to touch, taste, and temperature.
3. Temporal Lobe: Found on the bottom section of the brain, this lobe is important for processing auditory information and is also involved in certain aspects of speech and language perception.
4. Occipital Lobe: Located at the back of the brain, the occipital lobe is primarily responsible for vision.
These areas work together, enabling us to perform complex tasks such as learning, thinking, and comprehending languages.
Other Important Regions of the Brain
- Limbic System: The limbic system is a complex set of structures found on both sides of the thalamus, right under the cerebrum. It’s not a separate system, but a collection of structures that play significant roles in emotion, behavior, motivation, long-term memory, and olfaction. Key structures within the limbic system include the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus. The limbic system is often referred to as the “emotional brain” due to its substantial influence on our emotional responses.
- Hypothalamus: The hypothalamus is a small but crucial part of the brain located above the pituitary gland and below the thalamus. Despite its relatively small size, the hypothalamus performs a range of vital functions, especially in coordinating the body’s regulatory functions.
- The major roles of the hypothalamus include:
- Homeostasis: The hypothalamus is central to maintaining the body’s internal balance, or homeostasis. It helps regulate essential functions like temperature, fluid balance, body weight, and appetite.
- Hormone Regulation: It communicates directly with the pituitary gland, signaling it to release or inhibit hormone secretion into the bloodstream. These hormones can influence various body functions, including growth, blood pressure, and reproductive functions.
- Autonomic Control: The hypothalamus has control over the autonomic nervous system, which manages involuntary body functions like heart rate, blood pressure, digestion, and respiration.
- Circadian Rhythms: It also regulates the body’s circadian rhythm or biological clock, affecting sleep-wake cycles, feeding times, and other daily patterns of behavior.
- Emotional and Behavioral Responses: In conjunction with the limbic system, the hypothalamus plays a significant role in generating emotional responses and behaviors.
- Hunger and Thirst: The hypothalamus controls the sensations of hunger and thirst. It responds to levels of nutrients in the blood, and to hormones that signal the state of the stomach and intestines.
- The major roles of the hypothalamus include:
1. Afferent Nerves: AKA sensory nerves, they carry information from the sensory receptors to the brain and spinal cord. (Afferent nerves carry information AT from the brain)
2. Efferent Nerves: AKA motor nerves, they carry information out from the brain and spinal cord to effectors (muscles, glands). (Efferent nerves EFFECT an organ in the body)
3. Interneurons: Also known as association neurons, interneurons are located entirely within the central nervous system (CNS). They serve as the link between sensory and motor neurons in the spinal cord, enabling communication between them without waiting on a signal from the brain. Interneurons play a crucial role in reflexes, learning, memory, and higher cognitive functions. They interpret, store, and retrieve information from the CNS, determining an appropriate response to stimuli.
1. Alzheimer’s Disease: A progressive disorder that causes brain cells to degenerate and die, resulting in a continuous decline in thinking, behavioral, and social skills.
2. Parkinson’s Disease: A progressive nervous system disorder that affects movement, causing tremors, stiffness, and difficulty with balance.
3. Multiple Sclerosis: A chronic illness of the nervous system wherein the immune system attacks the protective covering of nerve fibers, causing communication problems between the brain and the rest of the body.
4. Stroke: A medical emergency where the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Two types of stroke exist, ischemic and hemorrhagic. Ischemic strokes occur when a blood vessel in the brain becomes blocked by a clot or other structure. Hemorrhagic strokes occur when a blood vessel bursts in the brain.
5. Transient Ischemic Attack: TIA’s are considered ‘mini strokes’ and produce similar symptoms, but the symptoms will resolve within 24 hours. It is difficult for an EMT to tell whether a patient with stroke symptoms has a TIA or stroke due to our limited time with the patient (<24 hours).
In conclusion, grasping these crucial medical terms related to the nervous system can significantly enhance communication and understanding in emergency medical settings. Keep in mind, though, that this list is just a starting point. To fully master these terms, it’s crucial to use them in practice regularly. With persistence and effort, you’ll become fluent in this critical medical language.