ciało-człowieka: Brain

Evidence: 100 • authority: 72

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as vision, hearing, and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing that information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity) and the endocrine system. While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord,…

Evidence: 41 • authority: 72

The evolution of the brain is the progressive development and complexity of neural structures over millions of years, resulting in the diverse range of brain sizes and functions observed across different species today, particularly in vertebrates. The evolution of the brain has exhibited diverging adaptations within taxonomic classes, such as Mammalia, and even more diverse adaptations across other taxonomic classes. Brain-to-body size scales allometrically. This means that as body size changes, so do other physiological, anatomical, and biochemical connections between the brain and body. Small-bodied mammals tend to have relatively large brains compared to their bodies, while larger mammal…

Evidence: 40 • authority: 88

Gene Duplication, Co-Option and Recruitment during the Origin of the Vertebrate Brain from the Invertebrate Chordate Brain. The brain of the basal chordate amphioxus has been compared to the vertebrate diencephalic forebrain, midbrain, hindbrain and spinal cord on the basis of the cell architecture from serial electron micrographs and patterns of developmental gene expression. In addition, genes specifying the neural plate and neural plate border as well as <i>Gbx</i> and <i>Otx</i>, that position the midbrain/hindbrain boundary (MHB), are expressed in comparable patterns in amphioxus and vertebrates. However, migratory neural crest is lacking in amphioxus, and although it has homologs of t…

Evidence: 32 • authority: 80

Common developmental genetic mechanisms for patterning invertebrate and vertebrate brains

Evidence: 32 • authority: 92

EEFSEC deficiency underlies a human selenopathy with primary neurodevelopmental origins via midbrain-hindbrain hypoplasia.. Bi-allelic mutations in EEFSEC, a key factor in selenoprotein synthesis, cause a severe human selenopathy characterized by developmental delay, spasticity, and profound cerebellar atrophy. While previous studies in invertebrate models framed this condition as an early-onset neurodegenerative disorder, the contribution of primary developmental defects to the severe brain malformations in patients has remained a critical unanswered question. Here, we address this gap using a zebrafish model of EEFSEC deficiency. We discovered that loss of eefsec function does not impair…

Evidence: 32 • authority: 92

Beneath the Surface: Aquatic Models Illuminate Host-Microbe Interactions.. Microbial outcomes emerge from dynamic interactions among host defenses, microbial traits, and environmental context. This narrative review examines aquatic host-microbe systems, with emphasis on zebrafish and Vibrio species, as experimentally tractable aquatic models for understanding how interactions shift across a spectrum from mutualism to pathogenesis. We first define major aquatic invertebrate and vertebrate models, highlighting how each balances scalability, genetic accessibility, physiological complexity, and translational relevance. We then use Vibrio species as a framework for moving beyond the pathogen ver…

Evidence: — • authority: 72

The human brain is the central organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activities of the body, processing, integrating, and coordinating the information it receives from the sensory nervous system. The brain integrates sensory information and coordinates instructions sent to the rest of the body. The cerebrum, the largest part of the human brain, consists of two cerebral hemispheres. Each hemisphere has an inner core composed of white matter, and an outer surface – the cerebral cortex – composed of grey matter. The cortex has an outer layer, the…

Evidence: — • authority: 72

The cerebrum (pl.: cerebra), telencephalon or endbrain is the largest part of the brain, containing the cerebral cortex (of the two cerebral hemispheres) as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In the human brain, the cerebrum is the uppermost region of the central nervous system. The cerebrum develops prenatally from the forebrain (prosencephalon). In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. The cerebrum is also divided into approximately symmetric left and right cerebral hemispheres. With the assistance of the ce…

Evidence: — • authority: 72

The axial twist theory (a.k.a. axial twist hypothesis) is a proposed scientific theory to explain the optic chiasm and contralateral brain of vertebrates. It suggests that the rostral part of the head is "turned around" with respect to the rest of the body. This end-part would consist of the face (eyes, nose, and mouth) as well as part of the brain (cerebrum and thalamus). The central nervous system would end up with a 180 degree twist right at the optic chiasm, and other body parts would be slightly moved as well. According to the hypothesis, the vertebrate body has a left-handed chirality. The axial twist theory competes with a number of other proposals. None of the proposed theories expl…

Evidence: — • authority: 72

Cephalization is an evolutionary trend in bilaterian animals in which, over a sufficient number of generations, special sense organs and nerve ganglia concentrate towards the front of the body, often producing an enlarged head. This is associated with the animal's movement direction and bilateral symmetry. Cephalization of the nervous system has led to the formation of a brain with varying degrees of functional centralization in three phyla of bilaterian animals, namely the arthropods, cephalopod molluscs, and vertebrates. Hox genes organise aspects of cephalization in the bilaterians.

Evidence: — • authority: 72

An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they were in the order of Opisthopora since the male pores opened posterior to the female pores, although the internal male segments are anterior to the female. Theoretical cladistic studies have placed them in the suborder Lumbricina of the order Haplotaxida, but this may change. Other slang names for earthworms include "dew-worm", "rainworm", "nightcrawler", and "angleworm" (from its use as angling hookbait). Larger terrestrial earthworms are also called megad…

Evidence: — • authority: 72

Arthropods ( AR-thrə-pod) are invertebrates in the phylum Arthropoda. They possess an exoskeleton with a cuticle made of chitin, often mineralised with calcium carbonate, a body with differentiated (metameric) segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior organs. Like their exteriors, the internal organs of a…