How is the cns and pns integrated

Sensory input is when the body gathers information or data, by way of neurons, glia and synapses. The nervous system is composed of excitable nerve cells neurons and synapses that form between the neurons and connect them to centers throughout the body or to other neurons. These neurons operate on excitation or inhibition, and although nerve cells can vary in size and location, their communication with one another determines their function.

These nerves conduct impulses from sensory receptors to the brain and spinal cord. The data is then processed by way of integration of data, which occurs only in the brain. After the brain has processed the information, impulses are then conducted from the brain and spinal cord to muscles and glands, which is called motor output.

Glia cells are found within tissues and are not excitable but help with myelination, ionic regulation and extracellular fluid. The nervous system is comprised of two major parts, or subdivisions, the central nervous system CNS and the peripheral nervous system PNS.

The CNS includes the brain and spinal cord. The major glands in the endocrine system are shown in Figure 4. The pituitary secretes hormones that influence our responses to pain as well as hormones that signal the ovaries and testes to make sex hormones. The pituitary gland also controls ovulation and the menstrual cycle in women.

Other glands in the endocrine system include the pancreas , which secretes hormones designed to keep the body supplied with fuel to produce and maintain stores of energy ; the pineal gland , located in the middle of the brain, which secretes melatonin , a hormone that helps regulate the wake-sleep cycle; and the thyroid and parathyroid glands , which are responsible for determining how quickly the body uses energy and hormones, and controlling the amount of calcium in the blood and bones.

The body has two triangular adrenal glands , one atop each kidney. The adrenal glands produce hormones that regulate salt and water balance in the body, and they are involved in metabolism, the immune system, and sexual development and function. The most important function of the adrenal glands is to secrete the hormones epinephrine also known as adrenaline and norepinephrine also known as noradrenaline when we are excited, threatened, or stressed.

Epinephrine and norepinephrine stimulate the sympathetic division of the ANS, causing increased heart and lung activity, dilation of the pupils, and increases in blood sugar, which give the body a surge of energy to respond to a threat.

The activity and role of the adrenal glands in response to stress provide an excellent example of the close relationship and interdependency of the nervous and endocrine systems. A quick-acting nervous system is essential for immediate activation of the adrenal glands, while the endocrine system mobilizes the body for action. The male sex glands , known as the testes , secrete a number of hormones, the most important of which is testosterone , the male sex hormone.

Testosterone regulates body changes associated with sexual development, including enlargement of the penis, deepening of the voice, growth of facial and pubic hair, and the increase in muscle growth and strength. The ovaries , the female sex glands , are located in the pelvis. They produce eggs and secrete the female hormones estrogen and progesterone.

Estrogen is involved in the development of female sexual features, including breast growth, the accumulation of body fat around the hips and thighs, and the growth spurt that occurs during puberty. Both estrogen and progesterone are also involved in pregnancy and the regulation of the menstrual cycle.

Recent research has pinpointed some of the important roles of the sex hormones in social behaviour. Dabbs, Hargrove, and Heusel measured the testosterone levels of men who were members of 12 fraternities at two universities.

They also obtained descriptions of the fraternities from university officials, fraternity officers, yearbook and chapter house photographs, and researcher field notes. The researchers correlated the testosterone levels and the descriptions of each fraternity.

They found that the fraternities with the highest average testosterone levels were also more wild and unruly, and one of these fraternities was known across campus for the crudeness of its behaviour. On the other hand, the fraternities with the lowest average testosterone levels were more well behaved, friendly and pleasant, academically successful, and socially responsible.

Banks and Dabbs found that juvenile delinquents and prisoners who had high levels of testosterone also acted more violently, and Tremblay and colleagues found that testosterone was related to toughness and leadership behaviours in adolescent boys.

Although testosterone levels are higher in men than in women, the relationship between testosterone and aggression is not limited to males. Studies have also shown a positive relationship between testosterone and aggression and related behaviours such as competitiveness in women Cashdan, Keep in mind that the observed relationships between testosterone levels and aggressive behaviour that have been found in these studies do not prove that testosterone causes aggression — the relationships are only correlational.

Recent research has also begun to document the role that female sex hormones may play in reactions to others. At this point you can begin to see the important role the hormones play in behaviour. But the hormones we have reviewed in this section represent only a subset of the many influences that hormones have on our behaviours.

In the chapters to come we will consider the important roles that hormones play in many other behaviours, including sleeping, sexual activity, and helping and harming others. Banks, T. Salivary testosterone and cortisol in delinquent and violent urban subculture. Journal of Social Psychology, 1 , 49— Cashdan, E. Hormones and competitive aggression in women. Aggressive Behavior, 29 2 , — Dabbs, J. This sensory input is sent to the central nervous system, which determines an appropriate response.

Once the response is activated, the nervous system sends signals via motor output to muscles or glands to initiate the response. In humans, the sophistication of the nervous system allows for language, abstract representation of concepts, transmission of culture, and many other features of society that would not otherwise exist. The CNS includes the brain and spinal cord, while the PNS is a network of nerves linking the body to the brain and spinal cord.

The nervous system is comprised of two major subdivisions, the central nervous system CNS and the peripheral nervous system PNS. The Central Nervous System : The central nervous system 2 is a combination of the brain 1 and the spinal cord 3.

The CNS includes the brain and spinal cord along with various centers that integrate all the sensory and motor information in the body. These centers can be broadly subdivided into lower centers, including the spinal cord and brain stem, that carry out essential body and organ-control functions and higher centers within the brain that control more sophisticated information processing, including our thoughts and perceptions.

Further subdivisions of the brain will be discussed in a later section. The nervous system is often divided into components called gray matter and white matter. Gray matter, which is gray in preserved tissue but pink or light brown in living tissue, contains a relatively high proportion of neuron cell bodies.

Conversely, white matter is composed mainly of axons and is named because of the color of the fatty insulation called myelin that coats many axons. White matter includes all of the nerves of the PNS and much of the interior of the brain and spinal cord. Gray matter is found in clusters of neurons in the brain and spinal cord and in cortical layers that line their surfaces. By convention, a cluster of neuron cell bodies in the gray matter of the brain or spinal cord is called a nucleus, whereas a cluster of neuron cell bodies in the periphery is called a ganglion.

However, there are a few notable exceptions to this rule, including a part of the brain called the basal ganglia, which will be discussed later. The PNS is a vast network of nerves consisting of bundles of axons that link the body to the brain and the spinal cord. Sensory nerves of the PNS contain sensory receptors that detect changes in the internal and external environment.

This information is sent to the CNS via afferent sensory nerves. Following information processing in the CNS, signals are relayed back to the PNS by way of efferent peripheral nerves. The autonomic system has involuntary control of internal organs, blood vessels, and smooth and cardiac muscles.

The somatic system has voluntary control of our movements via skeletal muscle. As mentioned, the autonomic nervous system acts as a control system and most functions occur without conscious thought.

The ANS affects heart rate, digestion, respiratory rate, salivation, perspiration, pupil diameter, urination, and sexual arousal. While most of its actions are involuntary, some, such as breathing, work in tandem with the conscious mind.

In truth, the functions of both the parasympathetic and sympathetic nervous systems are not so straightforward, but this division is a useful rule of thumb.

The enteric nervous system ENS controls the gastrointestinal system and is sometimes considered part of the autonomic nervous system. However, it is sometimes considered an independent system because it can operate independently of the brain and the spinal cord. The left-right pair of cranial nerves, spinal nerves, and ganglia make up the peripheral nervous system shown in dark gold.