ApoptosisApoptosis (from apóptōsis) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, DNA fragmentation, and mRNA decay. The average adult human loses between 50 and 70 billion cells each day due to apoptosis.
NeurotrophinNeurotrophins are a family of proteins that induce the survival, development, and function of neurons. They belong to a class of growth factors, secreted proteins that can signal particular cells to survive, differentiate, or grow. Growth factors such as neurotrophins that promote the survival of neurons are known as neurotrophic factors. Neurotrophic factors are secreted by target tissue and act by preventing the associated neuron from initiating programmed cell death – allowing the neurons to survive.
Programmed cell deathProgrammed cell death (PCD; sometimes referred to as cellular suicide) is the death of a cell as a result of events inside of a cell, such as apoptosis or autophagy. PCD is carried out in a biological process, which usually confers advantage during an organism's lifecycle. For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate. PCD serves fundamental functions during both plant and animal tissue development.
Cell deathCell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as diseases, localized injury, or the death of the organism of which the cells are part. Apoptosis or Type I cell-death, and autophagy or Type II cell-death are both forms of programmed cell death, while necrosis is a non-physiological process that occurs as a result of infection or injury.
DeathDeath is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including the brainstem, and brain death is sometimes used as a legal definition of death. The remains of a former organism normally begin to decompose shortly after death. Death is an inevitable process that eventually occurs in all organisms. Some organisms, such as Turritopsis dohrnii, are biologically immortal.
Development of the nervous systemThe development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The field of neural development draws on both neuroscience and developmental biology to describe and provide insight into the cellular and molecular mechanisms by which complex nervous systems develop, from nematodes and fruit flies to mammals.
Human brainThe human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of the body, processing, integrating, and coordinating the information it receives from the sense organs, and making decisions as to the instructions sent to the rest of the body. The brain is contained in, and protected by, the skull bones of the head.
Death (personification)Death is frequently imagined as a personified force. In some mythologies, a character known as the Grim Reaper (usually depicted as a berobed skeleton wielding a scythe) causes the victim's death by coming to collect that person's soul. Other beliefs hold that the Spectre of Death is only a psychopomp, a benevolent figure who serves to gently sever the last ties between the soul and the body, and to guide the deceased to the afterlife, without having any control over when or how the victim dies.
Fetal alcohol spectrum disorderFetal alcohol spectrum disorders (FASDs) are a group of conditions that can occur in a person who is exposed to alcohol as a result of their mother drinking during pregnancy. Symptoms can include an abnormal appearance, short height, low body weight, small head size, poor coordination, behavioral problems, learning difficulties, and problems with hearing and sight. Those affected are more likely to have trouble with school, the legal system, alcohol, other drugs, and other areas of high risk.
Galanin'Galanin' is a neuropeptide encoded by the GAL gene, that is widely expressed in the brain, spinal cord, and gut of humans as well as other mammals. Galanin signaling occurs through three G protein-coupled receptors. Much of galanin's functional role is still undiscovered. Galanin is closely involved in the modulation and inhibition of action potentials in neurons. Galanin has been implicated in many biologically diverse functions, including: nociception, waking and sleep regulation, cognition, feeding, regulation of mood, regulation of blood pressure, it also has roles in development as well as acting as a trophic factor.
