Human Body Systems: Nervous, Excretory, Digestive, Respiratory
Nervous System: Cells
The nervous system is composed of neurons and glial cells. Neurons transmit nerve impulses and do not regenerate. A neuron consists of a cell body, dendrites, and an axon. The space between neurons is called a synapse, where neurotransmitters facilitate communication. Nerve impulses travel from the cell body to the axon.
Types of Neurons:
- Sensory (afferent) neurons: Carry information from receptors to the central nervous system.
- Interneurons: Exist within the central nervous system
Chromosome Alterations and Genetic Engineering Techniques
Chromosomal Alterations
Structural Alterations
These affect the structure of chromosomes, impacting gene location. They are usually caused by errors in mitosis and meiosis, mainly affecting homologous chromosome pairing during prophase I. There are four types:
- Deficiencies or Deletions: Loss of a chromosome segment, affecting multiple genes. Example: Cri du chat syndrome.
- Duplications: Repetition of a chromosome segment, often in heterozygous series. Cytologically recognized during mating as a duplicated
Cellular Respiration and Fermentation Processes
Cellular Respiration
Cellular respiration is the process where glucose is completely oxidized to CO2 and H2O with O2 intervention. This catabolic pathway occurs in the mitochondria of eukaryotes or in the cytoplasm and plasma membrane of prokaryotes.
The pyruvate obtained in glycolysis is broken down in three stages:
1. Oxidative Decarboxylation of Pyruvate
Pyruvate from glycolysis enters the mitochondrial matrix and undergoes decarboxylation, releasing a CO2 molecule, while NAD+ is reduced to NADH.
Read MoreUnderstanding Species Evolution
What is a Species?
A species is defined as a group of organisms capable of interbreeding and producing fertile offspring.
How Does Evolution Occur?
Natural Selection
Charles Darwin proposed natural selection, or “survival of the fittest,” as the driving force behind evolution. For example, in a lion pride, the strongest cubs are more likely to survive and reproduce, passing on their advantageous traits. Over generations, these accumulated changes can lead to the emergence of a new species.
Jean-Baptiste
Read MoreMediastinum Anatomy and Fetal Circulation
Mediastinum
- Occupied by the tissue mass between the two lung cavities. Covered by the mediastinal parietal pleura on each side and contains all thoracic viscera and structures except the lungs.
- Extends from the upper chest opening to the diaphragm inferiorly, and from the sternum and costal cartilages anteriorly to the thoracic vertebral bodies posteriorly.
- High mobility due to mostly hollow visceral structures held by loose connective tissue, often infiltrated with fat.
Superior Mediastinum (Manubrium
Read MoreHuman Biology: Digestion, Respiration, Circulation, and Excretion
Digestive Function
Ingestion: Intake of food into the digestive tract through the mouth. Food is crushed by the teeth, mixed with saliva, and begins digestion.
Digestion: Processing of food into nutrients that can be utilized by cells. This occurs through two types of actions:
- Mechanical: Physically breaking down food through cutting, grinding, and churning. This occurs in the mouth and stomach.
- Chemical: Transforming food into simpler compounds using substances that cause chemical changes. This starts