Image from Unsplash
The nervous system is a body system that is made up of nerves and specialized cells, which are called neurons. Neurons transmit signals 💥 between different parts of the body. Due to this, the nervous system controls, regulates, and communicates all signals within the human body. There are two parts to your nervous system: the Central Nervous System (CNS) and Peripheral Nervous System (PNS).
The central nervous system is composed of your brain. The brain is the main control center 🎛 for actions such as movement 👋, sleep 😴, and hunger 😋. Your brain receives and interprets signals from other parts of the body, as well as from the external (outside) world.
Image from Unsplash
The cerebrum is the largest part of the brain. It helps interpret touch and other sensory signals. It also regulates speech 💬, emotion, reasoning, and learning.
The cerebellum coordinates muscle movement 💪 and balance 🏋. It is why we can perform actions like walking, riding a bicycle, and dancing.
The brainstem is responsible for postural control 💁, muscle tone 💪, and eye 👀 movement. This allows us to sit up straight and look to our right and left.
The diencephalon is a small part in the back 🔙 of the brain that is hidden from sight 👁 (if seen from the front). It consists of the thalamus, which controls our awareness of pain 😣 and screens incoming signals💥. The hypothalamus is also part of the diencephalon, and it controls body temperature 😷, appetite, emotions, and other automatic functions.
Located at the front of the brain
Controls personality and behavior
Controls emotions
Controls body movement
Controls judgment making and problem-solving
Controls speech
Located at the top of the brain
Controls the interpretation of language
Controls our senses
Controls perception—both spatial and visual
Lies on the sides of the brain
Controls our understanding of language
Controls hearing and memory
Image from Unsplash
The spinal cord is that pathway for information connecting the brain and the peripheral nervous system. As the spinal cord travels down the vertebral column, the spinal nerves branch 🌴 off between each vertebra.
The limbic system regulates basic drives and screens 👀 information, which enters the cerebral cortex. This system consists of the hippocampus, which creates new memories, and the amygdala, which integrates both memory and emotion.
Sympathetic System
The sympathetic nervous system helps make bodily adjustments to prepare the body for emergencies 🚑. This is where the “flight” or “fight” response 🙀 is activated through the release of adrenaline from the adrenal gland, increase in heart rate💓, and widening of blood vessels.
Parasympathetic System
The parasympathetic system functions are opposite to the sympathetic system. This is known as the “rest and digest” response. It helps the body return to its normal state after the sympathetic system is activated ✅.
💡 To remember these systems, think of the phrases “fight or flight” and “rest and digest”!
The somatic nervous system connects the central nervous system to muscles, tissues, and skin. Afferent, or sensory neurons, move impulses to the central nervous system. From here, efferent neurons take this signal to the muscles and other organs.
Alzheimer’s Disease is a progressive neurological disorder caused by the death of brain cells which results in memory loss 👇 and cognitive decline.
Some defining characteristics of Alzheimer’s disease are:
Decline in cognitive ability
Reduced ability to take in and remember new information
Impairment to reasoning, complex task, and judgment
Impaired visuospatial abilities
Epilepsy is a central nervous system disorder causing abnormal brain activity such as seizures 💫 and periods of unusual behavior. Disruptions in electrical activity in the central nervous system set off seizures, which cause nervous system symptoms such as heart palpitations.
Nervous System
Central Nervous System
Peripheral Nervous System
Cerebrum
Cerebellum
Brainstem
Diencephalon
Frontal Lobe
Parietal Lobe
Occipital Lobe
Temporal Lobe
The Spinal Cord
The Limbic System
The Autonomic Nervous System
Sympathetic System
Parasympathetic System
The Somatic Nervous System
Alzheimer’s Disease
Epilepsy
That’s all for the nervous system! For those of you who are visual 👁 learners, check out Fiveable’s
Overview of the Nervous System and the Neuron to review the material discussed in this chapter. For those of you who are more interactive ✋, check out our
Nervous System Slides. Finally, to recap your knowledge of the nervous system, check out the
Nervous System Video Review!
🤝Connect with other students studying biology with
Hours