Introduction to control and coordination - class-VIII

• The cerebral peduncles (also known as the cerebral crus) are the part of the midbrain that links the brainstem and the cerebrum of the brain. 
• They are the most anterior structure in the midbrain and contain the large ascending and descending tracts that run to and from the cerebrum. Hence, Cerebral peduncles connect the cerebrum of brain and brain stem.
So, the correct answer is 'Cerebral peduncles'.

• The pineal gland is a small endocrine gland in the brain stem. 
• The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. 
• The shape of the gland resembles a pine cone from which it derived its name.

The peripheral neural system has two parts- Automatic Neural System and Somatic Neural system. The PNS consists of all the nerves and ganglia other than that from the brain and spinal cord. SNS is associated with the voluntary control of body and ANS with the involuntary control movements of the body. The SNS consists of afferent nerves or sensory nerves, and efferent nerves or motor nerves. And the ANS consists of sympathetic and parasympathetic neural systems. Since no signal is carried from CNS so statement 1 is the correct answer. 

Peristalsis is an involuntary, rhythmic contraction of smooth muscles in the digestive tract, which is regulated by the autonomic nervous system. Swallowing involves both voluntary and involuntary phases, while pupillary reflex and knee jerk are somatic or autonomic reflexes, but peristalsis is the classic example of autonomic control of visceral organs.

The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: 

Neural crest cells of ectoderm migrate downward to form the dorsal root ganglia of the spinal nerves and the postganglionic sympathetic neurons. The sensory cells in the dorsal root ganglia give rise to dendrites extending to sense organs and axons extending into the spinal cord. Some other neural crest cells form parts of certain sense organs and parts of the head. Few head derivatives of the neural crest give rise to sensory nerves and other parts of the peripheral nervous system and ganglia of the autonomic nervous system. Thus, the correct answer is option C.

• The meninges are three layers of protective tissue called the dura mater, arachnoid mater, and pia mater that surround the neuraxis. 
• The meninges of the brain and spinal cord are continuous, being linked through the magnum foramen. 
• In order from the outermost to innermost layer, the meninges are dura mater, arachnoid mater, subarachnoid space, and pia mater. Hence, The innermost layer of meninges is Pia mater.

•  The central nervous system CNS is responsible for integrating sensory information and responding accordingly. 
• The major divisions of the brain are the forebrain (telencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon).
•  It consists of two main components: The spinal cord serves as a conduit for signals between the brain and the rest of the body. It also controls simple musculoskeletal reflexes without input from the brain. Hence, Rhombencephalon, Mesencephalon and Telencephalon are the components of central nervous system. 

Lymph is the fluid having the same composition as tissue fluid and is carried in lymph vessels. Osteocytes, the bone cells are the longest-lived cells. Chromatophores with black pigment present in certain parts of brain and retina are one of the largest cells at maturity; however, not it does not hold true for all chromatophores. Neurons are the largest cells that can be several feet long. Each neuron consists of the dendrite, axon and soma. Thus, the correct answer is option C.

Metamorphosis is the process by which an organism changes its form or habits during normal development after embryonic stage.
Gastrulation is the process, where there are cell movements, which result in the reorganization of the embryo from blastula to gastrula.
Neurulation is the process of folding in the embryos of vertebrates, where there is the transformation of neural plate into the neural tube. This process induces the formation of the central nervous system.
Invagination is the infolding of one part within another part and it involves the morphogenetic processes by which an embryo takes form and is the initial step of gastrulation.
Thus, the correct answer is the option (C), 'Neurulation'.

The parasympathetic nervous system is responsible for 'rest and digest' functions, such as increasing peristalsis and saliva secretion. Dilation of the pupil (mydriasis) is controlled by the sympathetic nervous system, not the parasympathetic.

The central nervous system (CNS) is primarily composed of association neurons (interneurons) that process information and facilitate communication between sensory and motor neurons. Sensory and motor neurons are primarily located in the peripheral nervous system.

GABA (gamma-aminobutyric acid) and Glycine are the primary inhibitory neurotransmitters in the central nervous system. They work by increasing chloride ion conductance, which hyperpolarizes the neuron and inhibits action potentials.

White matter with patches of grey matter. Neuroglia cells are connective tissue cells of central nervous system. 

The brain and spinal cord constitute the central nervous system, which acts as the control center for the body. They are classified as nervous organs because they are composed of nervous tissue.

In the central nervous system the nerve fibres are organized in bundles called tracts. Ascending tracts carry impulses along the spinal cord toward the brain, and descending tracts carry them from the brain or higher regions in the spinal cord to lower regions.  So, the correct answer is option C.

The nervous system is a highly integrated system. It has three overlapping functions based on sensory input, integration, and motor output. At a more interactive level, the primary function of the nervous system is to control and communicate information throughout the body.

Bundles of fibres or axons, in the peripheral nervous system, are called nerves, and bundles of afferent fibres are known as sensory nerves. An efferent nerve fibre conducts signals from a motor neuron in the central nervous system to muscles.

The CNS contains the brain and the spinal cord. Everything else but the CNS it is known as the PNS. The PNS contains nerves, which leave the brain and the spinal cord and travel to all the parts of the body.

$4$ pairs of cranial nerves are mixed nerves. These are trigeminal, facial, glossopharyngeal and vagus nerves.

• The cerebral cortex of the brain has three regions of function, namely Sensory, motor and association areas. 
• This association area does not belong either of the primary sensory or motor regions since its function is associative.
• The main function of these association regions is to provide a perpetual understanding of the world. it helps in effective interaction, abstract thinking, and language. 
• These association regions are present in the form of an interwoven network.

The visual system is the part of the central nervous system which gives organisms the ability to process visual detail as sight, as well as enabling the formation of several non-image photo response functions. In cerebrum, the visual centres are located on the occipital lobe.

So, the correct option is 'Occipetal lobe'.

The body's communication systems are the endocrine and nervous systems. At an integrative level, the primary function of the nervous system is to control many of the functions of our bodies and minds. It does this by extracting information from the environment using sensory receptors, sending signals that encode this information into the central nervous system, processing the information to determine an appropriate response, and sending output signals to muscles or glands to initiate the response. The nervous system responds rapidly to short-term changes. By nature, these hormones are synthesized at a distance from their target cells and travel through the bloodstream or intercellular fluid until they reach these cells. Upon reaching their target cell, the hormone acts on the cell to increase or decrease the expression of specific genes. This process takes significantly longer than that of the nervous system, as endocrine hormones must first be synthesized, transported to their target cell, and enter or signal the cell. Then, the target cell must go through the process of transcription, translation, and protein synthesis before the intended action of the hormone can be seen . 

Our nervous system is made up of brain, spinal cord, sense receptors and a whole lot of nerves. But all these are ultimately made up of nerve cells or neurons.

Body coordination in complex organisms is managed by the nervous system (fast, electrical signals) and the endocrine system (slower, chemical signals via hormones). Both systems work together to maintain homeostasis.

The autonomic nervous system, which includes both the sympathetic and parasympathetic divisions, regulates involuntary functions of visceral organs and involuntary muscles (smooth muscles).