![]() Birth complications such as hypoxic brain damage can occur if the umbilical cord blood supply is interrupted or compromised during birth. ![]() Other infections, which cause prenatal dysfunction, include toxoplasmosis, rubella, cytomegalovirus, HIV, herpes simplex, hepatitis B and syphilis. The Zika virus causes microcephaly, wherein the baby’s head is smaller than normal and the brain may not be fully developed. They can cause developmental problems and cerebral palsy in the case of chorioamnionitis. Infections can be transmitted across the placenta from the mother.Spina bifida is linked to a maternal deficiency of folic acid before or during the early stages of pregnancy. Nutritional deficiencies in the last 3 months of pregnancy can decrease the number of brain cells.Lead and mercury ingestion have been linked to intelligence, memory, learning and development problems. Tobacco ingestion has been linked to challenging behaviours and developmental impairment. Fetal alcohol syndrome is linked to alcohol ingestion during pregnancy. Neurotoxins can enter and damage a fetus’s nervous system, via the placenta leading to neurological problems as the child develops.Exposure to factors, which may hinder neural development in pregnancy, may cause intellectual, behavioural and developmental problems. Growth continues until at birth, all the major structures of the nervous system are present. The peripheral nervous system develops from the neural crest at around 4 weeks, alongside the spinal, cranial and autonomic nervous system. During the fourth and eleventh week, distinct areas of the brain are formed. To recap, the nervous system develops early in the third week of embryonic development to form a neural tube, in a process called neurulation. These occur in the womb during pregnancy. These include neurological dysfunction, cerebral dysfunction, head and spinal trauma, motor dysfunction, neurological tumours, infection and seizures. The nervous system is a highly complex and integrated system and disorders are categorised by their causative nature. The term applies to any condition that is caused by a dysfunction in the brain or nervous system, resulting in physical, behavioural and cognitive symptoms. This section will outline some of the common neurological disorders encountered in childhood. Other common synaptic neurotransmitters include serotonin and GABA (gamma‐aminobutyric acid). Dopamine and norepinephrine (noradrenaline) are found within the CNS and autonomic nervous system. These include acetylcholine in the CNS and at neuromuscular junctions. The third type of transmission occurs via chemical neurotransmitters at synaptic endings. The action potential jumps between the nodes of Ranvier, thus travelling much faster than by simple linear transmission. Saltatory conduction passes electrical action potentials along myelinated neurones. This causes polarisation and depolarisation along the neurone. Simple linear transmission passes electrical action potentials along neurones, through the exchange of sodium and potassium across cell membranes. There are three types of nerve impulse transmission in the nervous system. Neurones are nerve cells primarily involved with the transmission of information, while neuroglial cells provide a variety of supportive functions. Highly specialised neurone (nerve) and neuroglia (nerve fibre) cells provide the cellular building blocks of the nervous system. ![]() Physiologically, the nervous system is subdivided and organised as shown in Fig. The nervous system may be divided into the central nervous system (CNS) and peripheral nervous system (PNS). Table 8.1 Anatomical structure of the nervous systemįigure 8.1 Organisation of the nervous system. 8.1), to assist in understanding its complexity. While the nervous system functions as a whole, it is useful to subdivide its anatomical structure and physiological components ( Table 8.1, Fig. It provides us with instinctual information and reflexes, at birth and beyond. The nervous system assimilates experiences and information through memory, intelligence, learning and dreaming. It orientates us to the internal and external environment through sensory mechanisms. It is a complex system which co‐ordinates and controls voluntary and involuntary action. In conjunction with the endocrine system, the nervous system interacts with all body systems to maintain homeostasis.
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