Nervous Coordination

Nervous Coordination

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Have you ever wondered what sets plants and animals apart? Well, animals get their food from plants or other animals that have already eaten organic matter. To respond to changes in their environment, animals have a special nervous system that allows them to react quickly.

But did you know that some plants also eat organic matter from the soil or even trap insects? They also have special sense organs in their root tips and can react to stimuli in their environment, like theosa pudica plant that curls up its leaves when touched. Trees even communicate with each other through underground root networks, sending extra resources to their neighbors when they're in need.

All of these abilities are part of a complex system known as nervous coordination. So, next time you're out in nature, take a closer look at the plants around you – they may surprise you with their own unique adaptations!

An underground root network of wheatgrass
An underground root network of wheatgrass

Have you ever thought about what makes animals different from plants? Well, one key difference is the nervous system. Animals have a complex nervous system made up of individual units called neurons, which allow for quick and precise responses to stimuli in their environment. This makes rapid reactions the norm for animals, while plants tend to react more slowly to.

What is the definition of nervous coordination?

Have you ever heard of nervous coordination? It's when all the parts of an organism work together in harmony. There are different types of nervous coordination, including reflexes and voluntary movement. Reflexes are an automatic response to stimuli that enter the body through sensory neurons, causing muscle cells to contract. You might have had your reflexes checked by a doctor using a small hammer to hit the tendon below your knee (as shown in Figure 2) to test your nervous system's integrity.

Checking the knee reflex
Checking the knee reflex

Voluntary movement is also a reaction to a stimulus - the difference being that voluntary movement requires conscious control of the muscles. The interplay between the different parts of the body - the eyes, the nerve fibres, the spinal cord and muscles- is referred to as nervous coordination.

What is the role of the nervous system in nervous coordination?

The nervous system is responsible for nervous coordination and communication throughout the animal body. It's made up of specialised neurone cells that process and react to sensory input, as well as coordinate all the different elements in the body. Nerves are bundles of these neurones grouped together.

Neurones communicate with each other using synaptic transmission, which is mostly electrochemical. This communication occurs through neurotransmitters like acetylcholine, bridging the gap between neurones.

The nervous system can be subdivided based on the location or function of the nerves. However, there is some disagreement among researchers on the exact boundaries of these subdivisions, especially across different species. So, it's always best to follow the definitions in your specific textbook if you are unsure. Despite the complexity of the nervous system, it serves a vital role in ensuring that animals can respond to their environment and coordinate all activity within their bodies.

What are the two main subdivisions of the nervous system?

The nervous system can be subdivided into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS) (as shown in Figure 3).

The CNS, which consists of the brain and spinal cord, serves as the control centre for the entire organism. It's responsible for both conscious decisions and automatic reactions (reflexes) to stimuli. The PNS extends from the CNS and sends impulses to and from the CNS. The PNS is further subdivided based on function into two systems: the autonomic nervous system and the somatic nervous system. The autonomic nervous system can be either stimulated or calmed depending on the response, and it's overseen by the sympathetic nervous system (fight-or-flight response) and the parasympathetic nervous system (rest and digest response). To make the terms easier to remember, biopsychology texts often use acronyms for the nervous system divisions. You can remember the different functions for these acronyms as follows: C stands for Control in the Central nervous system, and A stands for Automatic in the Autonomic nervous system.

The components of the central nervous system

The CNS includes the brain and the spinal cord.

Defending from the toxins

The CNS has various physiological measures in place to prevent harmful toxins from entering it. One of these measures is the cerebrospinal fluid (CSF), which is a plasma-like fluid that circulates in and around the central nervous system. CSF has several molecular structures and membranes that function as security gates, preventing toxins from entering the brain even if they're already circulating in the body in substances such as blood. This means that although the brain and spinal cord connect to other nerves, the central nervous system is a closed system in itself. The presence of CSF and its various security gates ensures that harmful toxins are kept out of the central nervous system, protecting it from damage that could be caused by exposure to toxins.

The brain

When comparing the size of other mammals to human brains, it's interesting to note that the human brain-to-body ratio is similar to that of a mouse or monkey. This means that if a rat or mouse were as tall as a human, their brains would be the same size as the human brain. It's important to note that brains vary greatly across different organisms, with some animals not having a brain at all (such as jellyfish) and others having much larger brain-to-body ratios than humans (such as octopuses). However, the major structural difference between humans and other animals is the size of the cerebral cortex, which is the brain's surface area. The human cortex is much larger than that of other mammals, and is also more folded up than, say, a rat's smooth brain. This increased surface area of the cerebral cortex makes humans better at integrating information and planning than other animals. All conscious and unconscious decisions are made in the brain, which is why it's often referred to as the control centre of the body.

The spinal cord

The spinal cord is a tubular structure made up of nerves that extends from the brain into the peripheral nervous system. It stretches from the hindbrain at the base of the brain to the second lumbar vertebra in the lower back, about 5 cm above the pelvis.

Specialized neurons called relay neurons enable the body to react quickly to stimuli by carrying out unconscious reactions known as reflexes. Examples of reflexes include pulling your hand away from a hot plate, jumping when startled, and your knee jerking up when a doctor hits it. The spinal cord includes the nerve endings that connect to the peripheral nervous system. In the peripheral nervous system, nerves extend from clusters of neuron cell bodies called ganglia to all the muscles and senses in the body. Information is passed to and from the central nervous system (CNS) via the PNS. The information processed by the senses (such as smell, taste, and sight) and other receptors (such as touch, heat, and pain is passed to the CNS for integration. The peripheral nervous system is divided into two parts: the somatic nervous system and the autonomic nervous system. The somatic nervous system communicates with the senses and is responsible for the voluntary control of muscles. Any activity that you consciously control, such as moving your fingers or speaking, falls under the banner of the somatic nervous system. The autonomic nervous system is responsible for the involuntary and unconscious control of bodily processes such as heart rate, blinking, digestion, relaxation, and arousal. It works autonomously and is controlled by a specific part of the brain called the hypothalamus. The autonomic nervous system is further divided into two functional units: the sympathetic and parasympathetic nervous systems.

What is a neurone?

Neurons, also called nerve cells, are specialized cells found in the nervous systems of all animals. Their primary function is to transmit nerve impulses, which allows for communication within the nervous system. In the brain alone, there are an astounding 86 billion neurons that form a dense network, which is why they are commonly referred to as "brain cells." Neurons are not only found in the brain but also throughout the body, collecting information from the outside world through the senses and passing information from the brain to the muscles. This makes all movement and communication possible. For example, without your brain controlling the movement of your eye muscles, you wouldn't be able to read this text right now. Overall, neurons play a critical role in allowing organisms to sense, process, and respond to their environment. They are essential for maintaining homeostasis, allowing for complex behaviors and thoughts, and ultimately enabling the functioning of the entire nervous system.

What's the structure and function of a neurone?

All cells begin as embryonic stem cells and differentiate into specialized cells with different shapes and functions. Neurons have a unique structure specialized for transmitting information, with an input (dendrites) and an output (axon).

Dendrites are tree-like structures that grow from the cell body and receive information from neighboring cells. The axon is the long part of the neuron that carries impulses away from the cell body to other cells. Axons can range from a few micrometers to up to 25 meters long in whales.

Impulses always travel away from the cell body via the axon to the terminal buttons or axon terminals. Nerve impulses are unidirectional due to the action potential. Axons can also branch out, forming collaterals, and synapses are where nerve impulses are passed from one neuron to the next.

Myelin sheaths, made up of glial cells, wrap around axons and insulate electrical activity to prevent interference with other nerve impulses in the central nervous system. Myelin also speeds up the transmission of nerve impulses, and the more myelin that surrounds an axon, the faster the electrical impulse is sent to the next cell. The nodes of Ranvier are the bits of the axon where there are no myelin sheaths.

Types of neurones

Neurons are classified into three types: sensory neurons, interneurons, and motor neurons. Sensory neurons collect information and send it to the brain and spinal cord, while interneurons connect one neuron to another in the central nervous system. Motor neurons send information from the brain and spinal cord back to the muscles.

These three types of neurons work together to ensure proper functioning of the nervous system. Any disruption to this system can lead to severe illness in an organism. The conduction of nerve impulses through these neurons is essential in all actions, including reflexes.

For example, when you feel something wet on your cheek, sensory neurons send an afferent nerve impulse towards the central nervous system. The brain decides on a course of action, and relay neurons pass nerve impulses between neurons in the central nervous system to make the appropriate decision.

The brain then sends a command to the muscles, which contract to make your head jerk away from the unexpected stimulus. Motor neurons send an efferent nerve impulse to the muscles, causing them to move. You can remember afferent and efferent by AA and EE, respectively.

What's the function of motor neurones?

Motor neurons are responsible for making the body move by passing nerve impulses from the brain or spinal cord to the muscles or glands. They cause muscles to, which results in movement. Movement is a crucial aspect of life, from the beating of the heart to conscious movement of the muscles when walking.

Motor neurons have some of the longest axons in the human body, with some of them stretching from the spine to the foot. Schwann cells, specialized myelin sheaths, surround these axons, allowing the electrical impulse to travel faster over long distances without losing charge. Schwann cells can also repair damaged cells, which is not possible for oligodendrocytes in the central nervous system.

When motor neurons are damaged, individuals can have difficulty moving or controlling vital functions such as breathing, chewing, and swallowing. Muscle movement and coordination can be impaired, and individuals might experience twitching limbs or paralysis. Motor neuron diseases such as ALS and multiple sclerosis can have severe consequences for affected individuals.

What is the difference between the endocrine and nervous systems?

The nervous and endocrine systems are responsible for passing information, responding to stimuli, and creating homeostasis (biological balance) in the body.

Examples for comparison between nervous and endocrine systems.
Examples for comparison between nervous and endocrine systems.

Nervous Coordination - Key takeaways Nervous coordination is when all parts of an organism, including cells and organs, work together smoothly. The nervous system is a system of the body in charge of communication. The nervous system has two main divisions: the central nervous system (brain and spinal cord) and the peripheral nervous system (other parts excluding the brain and spinal cord).Nerves are a group of neurones. A cluster of neurone cell bodies is a ganglion. Like other cells, neurones have a cell membrane, cell body and nucleus. Unlike other cells, neurones have dendrites and an axon. There are three types of neurones; sensory, relay and motor neurones. The peripheral system can have voluntary and involuntary responses.

Nervous Coordination

What are the four main functions of the nervous system?

The four main functions of the nervous system are to maintain homeostasis, facilitate learning, control movement and spinal cord reflexes.

What is a coordinator in the nervous system?

The central nervous system is sometimes referred to as the nervous system coordinator, as it controls and coordinates all voluntary and involuntary functions in the body. 

What are the two types of nervous coordination?

The nervous system has three functions - sensing, processing and reacting. When divided by functions, the functions depend on the types of neurones.

What is coordination of the nervous system?

Coordination of the nervous system refers to the way neurones ensure that all the cells and organs in the body work together smoothly.

What does the central nervous system help coordinate?

The nervous systems helps coordinate all of the cells and organs in the body so that it functions optimally.

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