1. Brain cells and brains evolved pretty recently – about 250 million years ago, compared to the appearance of the first life-forms to arise.
• First evolved neurons and muscles to assist animals with movement.
• Nerve net – a connection of neurons that receive sensory information and send signals to other neurons that are involved in muscle movement.
• The first bilateral symmetry was described in flatworms, the nervous system on one side is almost identical to the other side, the human nervous system is arranged the same way.
• Segmentation, first observed in earthworms, whose bodies consist of several repeating segments, just like a human spinal cord.
• Ganglia. The first brain-like structure (a collection of neurons that function somewhat like brain) was found in clams, octopuses, snails, and insects.
• Spinal cord connects our brain and all the body parts senses. Was first found in highly evolved chordates.
• Brain. Amphibians, reptiles, birds, and mammals share this unique part of our central nervous system, but the human brain appears to be the largest relative to body size.
It is believed that our ancestors’ brains evolved from changing their life-styles: having an upright posture, constructing and using tools, and developing language.
2. The human brain and a spinal cord make up the central nervous system (CNS), which is responsible for mediating our behavior; it processes the afferent sensory information carried by the peripheral nervous system (PNS) – all
Each individual nerve is made up of: afferent nerves and efferent nerves where afferent nerves transmit impulses towards the nervous system from different parts of the body and efferent nerves transmit impulses away from the nervous system to the different parts of the body. The autonomic nervous system is another type of PNS responsible for involuntary actions like movement of heart, lungs, etc.
It was the 17th century British scientist Thomas Willis who recognized that the custard like tissue of the brain was where our mental world existed. The brain is an electric organ. Now we know that instead of animal spirits, voltage spikes travel through it and out into the body’s nervous system.
In the organization of the Human Nervous System it is divided into sections such as the sensory system, which gathers and process information from the surrounding environment: motor systems which responds from environment by sending signals and information to facilitate movement behavioral responses and the associational system which is a meditator from most multifaceted and least problematic brain functions. Within these different functions of the nervous system it is divided into two components where these functions can happen the central nervous system that comprises of brain and spinal cord and peripheral nervous system that embodies nerves and ganglia.
The other test held was an auditory test. The test was done in two different ways. One way was finding the objects in a bag that were mentioned verbally and the other was identifying the item reached by touch. This test’s results were also supporting the previous researchers’ logical conclusion about the left hemisphere ability of speech. It confirmed the right hemisphere’s ability of comprehending language and its ability of expressing it in a nonverbal way. During the test, evidently, the right hemisphere had no trouble identifying the unknown objects by touch as the left hemisphere did. Moreover, some three- dimensional drawings of the slit-brain patients, who were all right handed, developed much better drawings using their left hands compared with their right hands.
What is one of the oldest (evolutionarily) structures in the human brain? What does this structure do?
The brain stem or the medulla is the closest to the spinal cord. The brainstem is responsible for most of the human bodily functions. The brain stem is critical for human survival and normal human functions. The brain stem is also responsible for information of pain and touch from the head and neck; it is also responsible for the inputs from the face and the mouth. Reticular formation is a group of neurons, nuclei, that are important for sleep and wakefulness. In reticular formation there is nuclei that are a major source of neurotransmitter serotonin. Serotonin is important for regulating mood and activities.
The spinal cord and the brain are the main parts of the central nervous system. The spinal cord is aligned from the base of the brain, through the back, which allows the body to move and have sensation. The spinal cord contains dendrites, supporting cells, and axons, long nerve fibers, that attach to the brain to carry out messages. The axons have sheaths of insulation called myelin and the dendrites receive signals from other dendrites. Dendrites actually make
The peripheral nervous system, or PNS, is the part of the nervous system responsible with carrying sensory information (a person’s senses) and motor information (a person’s coordination) to and from the central nervous system (CNS, the part that takes the information and applies it to the body), as well as throughout the whole body. Both parts of the nervous system are made up of nerve cells, or neurons, which carry the electrical impulses that contain the information sent between the PNS and CNS. The neurons
There are two main divisions that comprise the nervous system: the central nervous system consisting of the brain and the spinal cord and the peripheral nervous system consisting of somatic and autonomic nervous systems (Kalat, 2013). The brain and the spinal cord make up the central nervous system and is responsible for the transmission of nervous impulses as well as receiving sensory information (Siegal, 1999). The peripheral nervous system, consisting of cranial nerves, spinal nerves, and peripheral ganglia, is responsible for transmitting information to the central nervous system as well as the rest of the body (Hubbard, 2013).
Throughout the years, our brain shape has changed in result of the nutrition received. The amount of nutrition received is the biggest factor with regard to the change in brain size. Therefore, the sufficient nutrition increased the size of the brain. In result, the increased brain size created advanced cognitive functions.
Whereas the spinal cord (often referred to as the brainstem) is the pathways that enables nerve impulses to reach their various destinations in the body. The central nervous system main function is to receive information from the different parts of the body, in which must be analysed and stored in order for it to send out instructions based on those pieces of information. The central nervous system’s main function is to coordinate the numerous organs and muscles required to perform the individual’s desired action(s) (Walker, 2005).
Even though the brain is the major control center if the body, its job would not be possible without the spinal cord. The spinal cord is the major organ that helps information travel between the body and the brain. Nerves branch in the peripheral system from, either the brain stem or spinal cord, each nerve attaches to a specific area of the torso and limbs it 's responsible for communication to and from those regions. There are three very important
The human nervous system is divided into two parts, the central nervous system and the peripheral nervous system. The central nervous system, CNS, is just the brain and spinal cord. The peripheral nervous system, PNS, includes the nerves and neurons that extend outwards from CNS, to transmit information to your limbs and organs for example. Communication between your cells is extremely important, neurons are the messengers that relay information to and from your brain.
The brain is aware of its surroundings, via input from the spinal cord and cranial nerves. Cranial nerves with sensory functions allow us to smell and see. Nerves with both motor and sensory functions are responsible for everything from tasting and chewing, to breathing and the heating of your heart. Many of the little things we take for granted are also made possible by cranial nerves.
In this same section, Shubin included Charles Darwin’s statement that makes it easier to understand. Humans have the same layout as other vertebrate creatures because we all came from a common descent (Shubin p. 32). Finally, the ancient fish, the Eusthenpteron, which we shared this limbs structure with was discovered in Devonian rocks around 380 million years old. It had the exact limbs structure as Owen described, however for this fish, the bones of the limbs were inside a fin (Shubin, p.33). This ancient fish unlocked the mystery that we are derived from a common ancestor that enable us to hold tools to do our everyday life tasks.