Human Reproductive System: From Puberty to Childbirth
Understanding the Reproductive Process
Fertilization and Early Development
Fertilization is the union between an ovum and a spermatozoon to form an egg cell, or zygote, from which a new individual will be formed. The most important phase of fertilization is the union of the nuclei of the two gametes, the ovum and spermatozoon, contributing 23 chromosomes each. This new cell, the zygote, contains 46 chromosomes and will develop into a new being.
When fertilization occurs in the Fallopian tubes, the
Read MoreAdvancements in Wound Treatment Techniques
Atualização no Tratamento de Feridas
FERIDA
Definição – 1
Qualquer lesão corporal que pode ou não apresentar solução de continuidade, varia de acordo com sua localização, agente ou causa.
Definição – 2
É definido como qualquer tecido epitelial ou mucoso que apresenta efeitos nocivos em suas funções básicas.
Introdução
A saúde é uma área de trabalho na qual a pesquisa científica e a prática clínica estão em constante progresso, visando melhorar a recuperação dos pacientes.
Animal Cells: Structure and Function
Key Biological Processes
- Nutrition: The process by which living matter absorbs and incorporates energy from the internal and external environment that surrounds it.
- Value: The process by which living beings receive information from the internal and external environment around them and adjust their operation to survive in that environment.
- Reproduction: The process by which living things give rise to other bodies that are similar or equal to them.
Eukaryotic Cell
Eukaryotic cells have their fundamental
Read MoreGametogenesis, Pollination, and Cellular Division: A Comprehensive Look
Gametogenesis
Gametogenesis occurs in gametes, encompassing spermatogenesis and oogenesis. Spermatogenesis involves the transformation of spermatogonia into spermatocytes of the 1st order. Through the 1st meiotic division, these become 2 spermatocytes of the 2nd order, which then yield 4 spermatids (n). Oogenesis begins in the embryonic stage. Oocytes of the 1st order are surrounded by follicular cells, forming primordial follicles. This process pauses until puberty. Each 1st order oocyte forms a
Read MoreOrigin of Life and Evolution Theories
Life’s Origin
Miller’s Experiment (The Primordial Soup Theory).
In 1953, Stanley Miller, and his professor, Harold Urey, performed an experiment that demonstrated how organic molecules could have spontaneously formed on early Earth from inorganic precursors. The now-famous “Miller-Urey experiment” used a highly reduced mixture of gases – methane, ammonia and hydrogen – to form basic organic monomers, such as amino acids.
Joan Oró
However, the current scientific consensus is that such was not
Read MoreCellular Transport: Passive and Active Mechanisms
Transport Across Membranes
- Plasma membranes separate the inner cellular environment (cytoplasm) from the extracellular environment (interstices- interstitial or extracellular space).
- Plasma membranes act as barriers to most, but not all, molecules.
- Plasma membranes are differentially permeable (semi-permeable).
- Materials move into and out of cells through passive transport or active transport.
1. Passive Transport
- Requires no energy from the cell.
- Requires a concentration gradient: unequal concentrations