Human Nervous and Endocrine Systems: A Comprehensive Study
Coordination Systems
Receiver: It perceives structures capable of receiving stimuli and transmitting them to the nerve centers. Any stimulus is called a change, both from the exterior and the interior of the body, capable of eliciting a response from the organism.
Nerve Centers: It is the organ in charge of receiving the information that the receptors collect, processing it, drawing up, and transmitting the appropriate responses to the effector organs.
Effectors: It is the organ in charge of carrying
Read MoreLevels of Organization in Living Matter: Molecular to Cellular
Molecular Level
It includes the molecules, formed by the group of atoms (bioelements). The organic molecules are referred to as biomolecules or immediate principles. These principles can be immediately divided into two categories: inorganic (water, minerals, ions, gases) and organic (carbohydrates, lipids, proteins, and nucleic acids).
At this level, we also group the macromolecules and viruses. The first result from the union of monomers (amino acids, nucleotides, etc.), and the second is the binding
Read MoreNervous and Endocrine Systems: Functions and Disorders
The Peripheral Nervous System
The peripheral nervous system is the part of the nervous system outside the brain and the spinal cord. It consists of both sensory and motor nerves. The nerves that connect with the brain, such as the optical, are called cranial nerves, and those that connect with the spinal cord, such as the sciatic nerve, are called spinal nerves.
The peripheral nervous system has two major parts:
- The somatic nervous system transmits information to the skeletal muscles and is responsible
Nervous System: Sensory Modalities and Receptor Functions
Information and Directions
The nervous system functions through physical contact between cells, neural circuits, and specialized areas that receive information. These areas are responsible for detecting environmental stimuli.
Law of Specific Nerve Energy: Each receptor is specific to a sensory modality and transmits an action potential via a specific nerve fiber to a particular area of the nervous system.
- Effectors: Output systems (endocrine system, muscles, etc.).
- Senses: Mechanisms for information
Evolution and the Origin of Humans: Darwin’s Insights
Evolution and Natural Selection
According to Darwin, in nature, there is a continuing struggle between individuals. Those with favorable changes are chosen by natural selection and, therefore, are the ones that survive.
Neutralists (Neo-Darwinism)
Neutralists attribute neutral genetic variability mainly to chance, i.e., mutations. Most argue that they are neutral with respect to natural selection. Only in some cases, mutations are favorable and are chosen by natural selection. Also, in the process
Read MorePlant Secretory Structures: Types and Functions
This document details the fascinating world of plant secretory structures, focusing on the mechanisms of substance excretion and the release of metabolic products. We will differentiate between external and internal secretory tissues.
External Secretory Tissues
External secretory tissues include glandular trichomes and other epidermal appendages. They are found throughout the plant and play roles in protection and absorption. Secretions can occur via:
- Diffusion through the membrane, predominantly involving