Control and coordination mechanism in living organisms is determined by the complex system of neurons or nerves called nervous system. Nervous system is divided into central nervous system and peripheral nervous system. In this blog, I’m going to explain parts of central nervous system.
Unicellular vs multicellular organisms nervous system
The basic difference between unicellular and multicellular organisms is that the multicellular organisms need both control and coordination over there life processes as well as system coordination. While unicellular organisms do not require such specialization. Central nervous system and peripheral nervous system are major parts of nervous system.
Meaning of nervous system
Nervous system is a vital controlling and coordinating mechanism of body. It is a complex system of neurons and nerves that carry information between brain and brainstem or spinal cord.
Need for nervous system
In living organisms, apart from reproduction, metabolism, growth, respiration, excretion, movement is also an important characteristic. For example, playing child, running cheetah, and, dog tearing flesh are the examples of movement in living organisms.
Hence, such movement need control and coordination among body systems to ensure better functioning. If the given organism acts in the external environment, it responses to the situation in which it lives.
Effective stimuli always invokes response to and compel organism to act accordingly. To do this job of control and coordination, there is nervous system made of neurons, nerves, that carry reflexes and impulses between brain and spinal cord.
Understanding parts of nervous system
At macro level, nervous system is divided as central nervous system and peripheral nervous system. Brain and the spinal cord are the parts of Central nervous system. While somatic and autonomic parts belong to peripheral nervous system.
Neurons and neurotransmitters
We know that nervous tissues are made of an organized network of neurons. It has following parts including nucleus, dendrite, cell body, axon, and nerve ending.
Like cell, neuron or nerve cell is a basic fundamental unit of nervous system. It is responsible to receive sensory information from the effective stimuli or environment. It commands to our muscles to perform specific function.
Technically, information is received at the dendrite tip of neurons. Dendrite generates electrical impulse that travels through cell body, axon and nerve ending. Finally, these electric impulses cross the gap called Synapse. Synapse is a gap between two nerve cells or neurons. Consequently, the next cycle begins in dendrite of next neurons.
In simple terms, network of neurons or nerve cells are specialized in transmitting information via electric impulse from one part of the body to another cell.
Explaining parts of Central nervous system brain and spinal cord
In human being, nervous system is divided as central nervous system, peripheral nervous system and autonomic nervous system.
Brain and spinal cord are major parts of central nervous system. Further, brain is divided into forebrain, midbrain and hindbrain. Cerebrum, thalamus, hypothalamus, pituitary gland, hypocampus, and limbic system.
I.Anatomical structure of forebrain
Cerebrum is the largest part with 85 percent of total brain, and divided into right and left hemispheres. Corpus callosum is a type of nerve fiber that connects two hemisphere of brain internally.
There are four lobes in which we divide brain. These are frontal lobes, parietal lobes, temporal lobes, and occipital lobes.
a) Function of frontal lobes
It controls voluntary motor activities and movement of muscles. Second, frontal lobes translate the thoughts into speech. It helps to express emotions. And it is powerhouse of intelligence, will power, memory, etc.
b) Role and function of parietal lobes
After frontal lobes, parietal lobes function to feel sensation like pain, temperature, pressure, and taste.
c) Importance of Temporal lobes
It helps to experience smell (olfactory), hearing, speech and emotions. Besides, it contains memory functions as well.
d) Occipital lobes is the fourth lobes in the cerebrum that have visual area for sense of vision.
Hypothalamus role and function
Hypothalamus is a part of forebrain. It forms the link between nervous and endocrine glands system. So, hypothalamus regulate heart rate, respiraton, blood pressure, body temperature and water and electrolyte balance.
In addition, hypothalamus controls and regulates hunger, thirst, sleep, satiety center, secretion of glands of digestive organs.
Limbic system of forebrain
It is a neuronal complex system that includes hypothalamus, parts of epithalmus, thalamus, hippocampus, etc. Limbic system is responsible for emotional reactions, motivational drives, and memory.
II. Understanding structure and function of midbrain
Midbrain is the part of brainstem and connects forebrain with hindbrain. Tectum, the cerebral aqueduct, the tegmentum, and the cerebral peduncles are the major parts of the midbrain.
It has centers of auditory, and visual reflexes to process auditory and visual information. So, it regulate eye movement, muscle movement, and helps other parts to do more functions.
III. Describing functions of hindbrain
Hindbrain is located in the posterior region of the brainbrain after forebrain and midbrain. Pons varolli, medulla oblongata, and cerebellum are the major parts of the hindbrain.
Actually, brain stem consists of midbrain, pons, and medulla oblongata and connects to spinal cord.
a) Pons varolli looks rounded on the underside of the brain stem. It plays important role in the functioning of breathing, digesting, and motor functions of neck.
b) The medulla oblongata controls involuntary body functions like heart beat, respiration, vasomotor activities and peristalsis. It also controls coughing, sneezing, swallowing, vomiting, yawning etc.
c) The cerebellum is the important part of hindbrain. It is the second largest part of the brain. Cerebullar penduncles connects cerebellum to the other parts of the central nervous system.
Cerebellum functions to maintain equilibrium of body, posture, balancing orientation moderation of voluntary movement and maintaince of muscle tone.
Spinal cord — parts of central nervous system
Central nervous system consists of brain and spinal cord. It forms the lower extension of medulla oblongata. It lies within the neural canal of the vertebral column.
Spinal cord forms the connecting rod between brain and muscle reflexes of the body. It acts as highway for sensory and motor reflexes. Obviously, spinal cord connects brain to the whole body via nerve cells or neurons. Beyond the spinal cord, peripheral nervous system begins.
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