Neuroendocrine cell
Encyclopedia
Neuroendocrine cells are cells that receive neuronal input (neurotransmitters released by nerve cells) and, as a consequence of this input, release message molecules (hormones) to the blood. In this way they bring about an integration between the nervous system
and the endocrine system
, a process known as neuroendocrine integration. An example of a neuroendocrine cell is the cell of the adrenal medulla
(innermost part of the adrenal gland
) which releases adrenalin to the blood. The adrenal medullary cells are controlled by the sympathetic division
of the autonomic nervous system
. These cells are modified postganglionic neurons. Autonomic nerve fibers lead directly to them from the central nervous system. The adrenal medullary hormones are kept in vesicles much in the same way neurotransmitters are kept in neuronal vesicles. Hormonal effects can last up to ten times longer than those of neurotransmitters. Sympathetic nerve
fiber impulses stimulate the release of adrenal medullary hormones. In this way the sympathetic division of the autonomic nervous system and the medullary secretions function together.
The major center of neuroendocrine integration in the body is found in the hypothalamus
and the pituitary gland
. Here hypothalamic neurosecretory cells release factors to the blood. Some of these factors, released at the median eminence, control the secretion of pituitary hormones, while others (the hormones oxytocin and vasopressin) are released directly to the peripheral circulation.
APUD cells are considered part of the neuroendocrine system, and share many staining properties with neuroendocrine cells.
. They are located in the nasal respiratory epithelium, laryngeal mucosa and throughout the entire respiratory tract from the trachea
to the terminal airways. PNEC and NEB exist from fetal stage and neonatal stage in lungs airway area.
These cells are bottle- or flask-like in shape, and reach from the basement membrane
to the lumen
. They can be distinguished by their profile of bioactive amines and peptides, namely serotonin, calcitonin, calcitonin gene-related peptide (CGRP), chromogranin A, gastrin-releasing peptide (GRP), and cholecystokinin.
These cells can be the source of several types of lung cancer.
detection. This is best supported by the presence of an oxygen-sensitive potassium channel coupled to an oxygen sensory protein in the lumenal membrane in the rabbit. They are considered to be involved in regulating localized epithelial cell growth and regeneration through a paracrine mechanism, whereby their bioactive peptides are released into the environment. Additionally, they contain neuroactive substances which are released from their basal cytoplasm. These substances affect autonomic nerve terminals or vasculature in the lamina propria
deep to the cells.
in the brain
(in a region called the hypothalamus
). This area controls most anterior pituitary
cells and thereby regulates functions in the entire body, like responses to stress
, cold, sleep
, and the reproductive system
. The neurons send processes to a region connecting to the pituitary stalk
and the hormones (called releasing or inhibiting hormones) are released into the blood stream. They are carried by portal vessels to the pituitary cells where they may stimulate, inhibit, or maintain the function of a particular cell type.
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
and the endocrine system
Endocrine system
In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. It derives from the Greek words "endo"...
, a process known as neuroendocrine integration. An example of a neuroendocrine cell is the cell of the adrenal medulla
Adrenal medulla
The adrenal medulla is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine , norepinephrine , and a small amount of dopamine in response to...
(innermost part of the adrenal gland
Adrenal gland
In mammals, the adrenal glands are endocrine glands that sit atop the kidneys; in humans, the right suprarenal gland is triangular shaped, while the left suprarenal gland is semilunar shaped...
) which releases adrenalin to the blood. The adrenal medullary cells are controlled by the sympathetic division
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
of the autonomic nervous system
Autonomic nervous system
The autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...
. These cells are modified postganglionic neurons. Autonomic nerve fibers lead directly to them from the central nervous system. The adrenal medullary hormones are kept in vesicles much in the same way neurotransmitters are kept in neuronal vesicles. Hormonal effects can last up to ten times longer than those of neurotransmitters. Sympathetic nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
fiber impulses stimulate the release of adrenal medullary hormones. In this way the sympathetic division of the autonomic nervous system and the medullary secretions function together.
The major center of neuroendocrine integration in the body is found in the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
and the pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...
. Here hypothalamic neurosecretory cells release factors to the blood. Some of these factors, released at the median eminence, control the secretion of pituitary hormones, while others (the hormones oxytocin and vasopressin) are released directly to the peripheral circulation.
APUD cells are considered part of the neuroendocrine system, and share many staining properties with neuroendocrine cells.
Pulmonary neuroendocrine cells
Pulmonary neuroendocrine cells (PNEC) are specialized airway epithelial cells that occur as solitary cells or as clusters called neuroepithelial bodies (NEB) in the lungLung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
. They are located in the nasal respiratory epithelium, laryngeal mucosa and throughout the entire respiratory tract from the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
to the terminal airways. PNEC and NEB exist from fetal stage and neonatal stage in lungs airway area.
These cells are bottle- or flask-like in shape, and reach from the basement membrane
Basement membrane
The basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.- Composition :...
to the lumen
Lumen (anatomy)
A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...
. They can be distinguished by their profile of bioactive amines and peptides, namely serotonin, calcitonin, calcitonin gene-related peptide (CGRP), chromogranin A, gastrin-releasing peptide (GRP), and cholecystokinin.
These cells can be the source of several types of lung cancer.
Function of pulmonary neuroendocrine cells
PNEC may play a role as chemoreceptors in hypoxia (medical)Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
detection. This is best supported by the presence of an oxygen-sensitive potassium channel coupled to an oxygen sensory protein in the lumenal membrane in the rabbit. They are considered to be involved in regulating localized epithelial cell growth and regeneration through a paracrine mechanism, whereby their bioactive peptides are released into the environment. Additionally, they contain neuroactive substances which are released from their basal cytoplasm. These substances affect autonomic nerve terminals or vasculature in the lamina propria
Lamina propria
The lamina propria is a constituent of the moist linings known as mucous membranes or mucosa, which line various tubes in the body ....
deep to the cells.
Role of PNEC in fetal lung
In the fetal lung, they are frequently located at the branching points of airway tubules, and in humans are present by 10 weeks gestation. Peptides and amines released by PNEC are involved in normal fetal lung development including branching morphogenesis. The best-characterized peptides are GRP, the mammalian form of bombesin, and CGRP; these substances exert direct mitogenic effects on epithelial cells and exhibit many growth factor-like properties.Example
Specialized groups of neuroendocrine cells can be found at the base of the third ventricleThird ventricle
The third ventricle is one of four connected fluid-filled cavities comprising the ventricular system within the human brain. It is a median cleft between the two thalami, and is filled with cerebrospinal fluid ....
in the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
(in a region called the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
). This area controls most anterior pituitary
Anterior pituitary
A major organ of the endocrine system, the anterior pituitary, also called the adenohypophysis, is the glandular, anterior lobe of the pituitary gland...
cells and thereby regulates functions in the entire body, like responses to stress
Stress (biology)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
, cold, sleep
Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...
, and the reproductive system
Reproductive system
The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes...
. The neurons send processes to a region connecting to the pituitary stalk
Pituitary stalk
The pituitary stalk is the connection between the hypothalamus and the posterior pituitary....
and the hormones (called releasing or inhibiting hormones) are released into the blood stream. They are carried by portal vessels to the pituitary cells where they may stimulate, inhibit, or maintain the function of a particular cell type.