Neurons, Nervous System, and Sensory Organs: Biology
Neurons: Structure and Function
Neurons are composed of three main parts:
- Cell Body: The thickest part of the neuron, containing the nucleus and most organelles.
- Axon: A large prolongation extending from the cell body, branching out at its end.
- Dendrites: Small, branching prolongations of the cell body.
Neurons connect through dendrites and axons. The small gap separating the dendrites and the branched ends of the axon is called the synapse. They transmit information via electrical signals at speeds
Read MoreUnderstanding Biomolecules: Carbohydrates, Lipids, and Proteins
Biomolecules: Carbohydrates, Lipids, and Proteins
Heteropolysaccharides and Heterosides
Heteropolysaccharides are formed by two or more classes of monosaccharides. Heterosides are formed by a carbohydrate and a non-carbohydrate part.
Lipids
Lipids are a very heterogeneous set of substances, both structurally and by the functions they perform. They are insoluble in water and soluble in organic solvents. Chemically, they are made of Carbon, Hydrogen, and Oxygen.
Properties of Lipids
- Oily to the touch
Biological
Read MoreKey Concepts in Biology: Evolution, Digestion, and More
Darwin: The Theory of Evolution by Natural Selection
Darwin’s theory of evolution by natural selection is based on the following principles:
- There are heritable differences between individuals in a living population.
- More individuals are born than can survive.
- Some hereditary variations provide individuals with advantages in survival.
The Synthetic Theory of Evolution
This theory incorporates the idea of evolution by natural selection. The evolutionary unit is not the individual but the population. Differential
Read MoreBrain, Nervous & Endocrine Systems: Functions & Hormones
Brain Functions
The two cerebral hemispheres are connected by bundles of nerve fibers, which form the corpus callosum. Most sensory information from the right side of the body passes through the corpus callosum towards the left hemisphere.
The cortex integrates sensory stimuli; in association areas, it produces voluntary motor commands.
Association areas are responsible for higher functions (language, creativity, learning, and memory).
The sensory and motor areas of the brain are so well-known that
Read MoreUnderstanding the Peripheral Nervous System
Peripheral Nervous System
Somatic Nervous System
The somatic nervous system consists of:
- Spinal Nerves: These nerves transmit sensory information (touch, pain) from the trunk and extremities to the central nervous system via the spinal cord. They also relay information about the position and state of muscles and joints. Additionally, they carry motor commands from the spinal cord to skeletal muscles.
- Cranial Nerves: These nerves transmit sensory information from the head and neck to the central nervous
Cell Cycle: Flow Cytometry, Interphase, and Cell Division
Flow Cytometry
Interface: G1 – S – G2
When the cell is not in cell division, it is in interphase:
- G1 – State: Initiation of the cell’s life cycle.
- S – Synthesis of DNA, DNA duplication.
- G2 – The cell enters a resting state.
Interphasic Nucleus
Organelle characteristic of eukaryotic cells.
- Form: Ovoidal
- Location: In animal cells, it is at the center; in plant cells, it is on the side.
- Size: Approximately 5 microns in animal cells.
- Number: 1 nucleus in animal and plant cells; 2 nuclei in fungi. There are also