Anatomy and Physiology of the Ear: From Outer to Inner Ear
External Ear
The external ear is composed of the pinna and ear canal.
Pinna
The pinna, or auricle, is an irregularly folded, sheet-like structure that protrudes from the side of the head. It is attached around the external auditory meatus of the temporal bone. The central depressed area is called the concha and is surrounded, especially above and behind, by two prominent ridges: the helix and the antihelix. These ridges are separated by a distinct groove.
In front of the lower concha is the entrance
Read MoreIntroduction to Public Health and Diseases
Health and Disease
What is Health?
Health is a state of complete physical, mental, and social well-being. It is influenced by a series of factors such as:
- Heredity: Genetic factors
- Environment: Physical and chemical factors
- Personal Behavior: Lifestyle choices like diet and exercise
- Access to Health Systems: Availability of healthcare services
Health Risk and Risk Factors
Health risk is the probability of an event or damage to health that can cause illness or death. A risk factor is any circumstance or
Read MoreHeart, Kidney, and Urinary System Anatomy
Heart
Structure
The heart is a hollow, muscular organ responsible for pumping blood throughout the body. It is divided into four chambers: two atria (upper chambers) and two ventricles (lower chambers). The heart is enveloped by a protective membrane called the pericardium.
Layers of the Heart (from inside out):
- Endocardium
- Myocardium
- Epicardium
Chambers of the Heart:
- Top: Right Atrium, Left Atrium
- Bottom: Right Ventricle, Left Ventricle
The atria are separated by the interatrial septum, and the ventricles
Read MoreThe Nervous System: Structure, Function, and Divisions
The Nervous System
The nervous system allows the body to react to internal and external environmental changes. It controls and integrates various bodily activities.
Divisions of the Nervous System
Structurally, the nervous system is divided into the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
Functionally, it’s divided into the Somatic Nervous System (SNS) and the Autonomic Nervous System (ANS).
Nerve Tissue
Nerve tissue comprises two main cell types:
Neurons
Neurons are characterized
Read MoreIntroduction to Molecular Genetics
Session 4: Molecular Genetics
1. Explain the Chemical Structure of RNA
Ribonucleic acid (RNA) is composed of three different molecules:
A pentose D-ribose.
One of the following nitrogenous bases:
Purine: adenine (A) and guanine (G).
Pyrimidine: cytosine (C) and uracil (U).
A molecule of phosphoric acid.
The binding of ribose by a carbon-nitrogen base 1 of the pentose is called a nucleoside, and a nucleoside binding to a molecule of phosphoric acid through the 5′ carbon of deoxyribose is called a nucleotide.
Read MoreHeredity and Inheritance: Understanding Genetics
Heredity and Inheritance
What is Heredity?
Heredity is the passing of physical characteristics from parent to offspring. These characteristics are called inherited traits and are determined by one or many genes (e.g., eye color, hair and skin color, height).
Chromosome Theory of Inheritance
According to the chromosome theory of inheritance, genes are carried from parents to their offspring on chromosomes. In sexual reproduction, genetic material from two parents combines to produce a new organism, which
Read More