Human Biology: Auditory, Visual, Olfactory, Gustatory & Tactile Senses
Organs
Auditory System
The ear consists of three parts: the outer ear, middle ear, and inner ear.
Outer Ear
Composed of the pinna, ear canal, and eardrum, the outer ear collects and transmits sound waves to the middle ear. The ear canal contains small hairs and wax-producing glands for protection. The eardrum is a membrane separating the outer and middle ear.
Middle Ear
This section contains the tympanic cavity with three openings: one closed by the eardrum, and two inward openings called the oval window
Read MoreDisease Classification and Etiology
Disease Classification
Genetic Diseases
These diseases arise from modifications in the genome. Hereditary diseases occur when these modifications are passed down through generations. If the alteration is on a sex chromosome, it results in a sex-linked inherited disease, typically affecting only one sex. Mitochondrial inherited diseases involve modifications in mitochondrial DNA, always originating from the mother.
Degenerative Diseases
These involve impaired regenerative ability. Sometimes, the body
Read MoreConnective Tissue: Cells, Fibers, and Functions
Connective Tissue
Derived from the mesenchyme, embryonic star-shaped cells establish contact through cytoplasmic extensions, forming a lattice structure. Mesenchyme originates from two tissue groups:
- Connective, cartilage, and bone tissues.
- Blood and hematopoietic tissues.
Connective Tissue Composition
Connective tissue comprises cells and fibers within a fundamental and immigrant substance.
Connective Tissue Cells
Connective tissue cells are numerous and varied, divided into two groups:
Fixed Cells
These
Read MoreOrigins and Evolution of Life: A Comprehensive Overview
1. Main Ideas About the Origin of Life
Several key ideas address the origin of life:
- Creationism
- Spontaneous Generation
- Panspermia
- Evolutionary Theories
2. Creationism
Creationism posits a divine origin for life. It is not considered a scientific theory because it is not based on observable evidence and cannot be tested.
3. Spontaneous Generation
This idea suggests that living beings could arise from non-living matter.
4. Scientists Who Disproved Spontaneous Generation
Louis Pasteur and Francesco Redi designed
Read MorePhotosynthesis: Process, Phases, and Pigments
Autotrophic and Heterotrophic Anabolism
Autotrophic anabolism is the synthesis of complex molecules from simple inorganic molecules such as glucose or glycerol. Heterotrophic anabolism is the transformation of simple organic molecules into more complex ones, like starch. There are two types of autotrophic anabolism based on the energy source: photosynthetic anabolism, which uses light energy (e.g., photosynthesis in plants, cyanobacteria, and photosynthetic bacteria), and chemosynthetic anabolism,
Read MoreHuman Digestive System: Functions and Processes
Mouth
Digestive Functions
- Mechanical Decomposition: Chewing
- Chemical Digestion: Salivary glands secrete enzymes.
- Serous (watery): Contains ptyalin or amylase for starch digestion.
- Mucosa: Lubricates food, protects oral mucosa, and facilitates swallowing.
Saliva Functions
- Protects dental mucosa
- Cleans teeth
- Starts carbohydrate digestion
- Helps form the bolus
- Lubricates the oral cavity and pharynx
- Dissolves chemical substances for taste perception
- Immune function
Salivary Glands
- Major Glands: Parotid, submaxillary,