Understanding the Human Body: Circulatory, Digestive, Urinary, and Respiratory Systems
The Human Body: An Overview of Key Systems
The human body functions through a complex network of interconnected systems. From the tips of our toes to the top of our head, a vital fluid called blood circulates, delivering essential nutrients and removing waste. This journey is facilitated by a sophisticated system of vessels, powered by the heart, a tireless pump located in the center of the chest.
The Circulatory System
The circulatory system, also known as the cardiovascular system, is responsible
Read MoreCell Cycle: Mitosis and Meiosis Explained
The Cell Cycle
The cell cycle is the sequence of modifications that a cell undergoes from its formation until it splits to form two daughter cells. The duration depends on the cell type and environmental conditions. It consists of two main phases:
- Interphase: The initial, long-duration phase where the interphase nucleus is visible. The cell grows and performs many functions. DNA replication takes place at the end of this phase.
- Division Phase (M Phase): The final, short-duration stage where the nucleus
Calcium and Potassium: Effects on Cardiac Function
Calcium Regulation
The normal level of calcium in the body is 9.4 mg/dl. Calcium is needed for muscle contraction and is regulated by hormonal secretion. Hypocalcemia is seen when levels are less than 8 mg/100 ml, and below 7 mg/100 ml, tetany occurs, causing muscle contraction and contracture, including major cardiac systole. Hypercalcemia is diagnosed when levels are over 12 mg/100 ml; this delays body functions, and the heart does not contract properly. Certain hormones are responsible for maintaining
Read MoreStimulus and Response: Nervous, Hormonal Systems
Stimulus and Response in Living Organisms
A stimulus is a change that occurs in the external or internal environment and provokes a response in the body. The relations function is carried out by coordination systems:
- Receptor organs (receive stimuli)
- Coordination centers (analyze information and elaborate a response)
- Effector organs (execute responses)
Coordination may be nervous or hormonal.
Nervous Coordination
The synapse is the functional union where the nervous impulse passes from one neuron to another
Read MoreHuman Body Tissues: Characteristics and Types
Tissues: General Characteristics, Histogenesis, and Classification
Tissues are a combination of cells and their products that have the following in common:
- Embryonal origin
- Morphology
- Functions
There are six general types of tissue in our body:
- Epithelial
- Connective
- Muscle
- Nerve
- Blood
- Reproductive
Epithelial Tissue
Epithelial tissue forms the border between the inner and outer environment.
- Covers surfaces in a uni- or multi-stratified manner.
- Almost no extracellular matrix (ECM).
- No blood supply.
- Functions include:
Understanding Genome Mutations, Aneuploidy, and Mutagenic Agents
Genome Mutations
Genome mutations affect the number of chromosomes characteristic of a species. These mutations appear to be related to abnormal segregation of chromosomes during meiotic division. We distinguish two main types: aneuploidy and euploidy.
Aneuploidy
Aneuploidy consists of a change in the number of chromosomes, either by gain or loss of one or more chromosomes. There are several types:
- Nullisomy: Missing a pair of homologous chromosomes (2n-2 chromosomes).
- Monosomy: Missing a single chromosome