Understanding the Excretory and Urinary Systems: Functions and Anatomy
The Excretory System: An Overview
The excretory system comprises the urinary system and other organs and systems that aid in waste product excretion.
Other Components of the Excretory System
- Respiratory System: Removes carbon dioxide from the blood and expels it from the body.
- Sweat Glands: Located in the skin, these glands produce sweat, which evaporates to cool the skin. Some excretory substances are also eliminated through sweat.
- Liver: Eliminates products from the breakdown of hemoglobin from old
Cilia: Structure, Function, and Movement Mechanisms
Cilia: Structure, Function, and Movement
Cilia are mobile cytoplasmic extensions, typically 5 to 10 μm in length and 0.2 μm thick. They contain an axoneme and project from the free surface of many cells. Cilia function to move crawling or rolling particles, agitate and circulate fluids across surface epithelia, such as in the respiratory tract and certain excretory tubes of the testis.
Cilia originate from basal corpuscles. Structurally, a cilium is composed of the axoneme and ciliary membrane,
Read MoreHuman Body Systems: Functions, Homeostasis, and Feedback
1. Fill in the Blank Spaces
- What is the smallest unit of life in the human body? Cell
- Cells group together to form tissue.
- Tissues are grouped together to form various organs.
- Organs work together as part of a system.
2. Match the System with its Function
| Human Body System | Function |
|---|---|
| Skeletal System | Support |
| Muscular System | Movement |
| Respiratory System | Oxygen/Carbon Dioxide Exchange |
| Cardiovascular System | Transport |
| Excretory System | Waste Removal |
| Nervous System | Sends Chemical Messages |
| Lymphatic System | Returns Fluids |
| Integumentary |
Neo-Darwinism, Consanguinity, and Precambrian Era: Key Concepts
Neo-Darwinism
Although Darwin made significant contributions to evolutionary thought, his theory could not fully explain how hereditary traits are passed from generation to generation, nor the cause of variability within populations upon which natural selection acts. Evolution is a phenomenon of populations, not individuals. It is the population that evolves, as this is where genetic variability is present, allowing selection to act.
It wasn’t until the 20th century that the synthesis of Darwin’s
Read MoreUnderstanding Evolution: Key Concepts and Processes
Understanding Evolution: Key Concepts
- Definition of Evolution: Change over time.
- Definition of Biological Evolution: Change in the genetic makeup of a population from generation to generation.
- Darwin’s Theory of Evolution by Natural Selection: Influenced by Wallace, Darwin published On the Origin of Species in 1859, laying out his theory of natural selection and providing significant evidence to support it.
- Definition of Gene Pool: The sum of all of the genetic information of all of the members of a
Evolutionary Theories: Neutral, Punctuated Equilibrium & Population Genetics
Evolutionary Theories and Population Genetics
Genetic recombination during meiosis results in offspring variations. These variations occur randomly and are pre-adaptive.
Hardy-Weinberg Principle
Hardy and Weinberg demonstrated that in a population (k) + tax, individuals die and lose characteristics, but the population remains. The genetic stocks are all individuals with the ability to reproduce sexually with each other.
Evolutionary Forces
Fisher, Haldane, and Wright demonstrated that changes in gene
Read More