Cellular Responses and Nutrition: Metabolism, Movement, and Growth
Cellular Responses
At the molecular level, responses are varied, as all metabolic processes in cells occur as responses to stimuli. Cell behavior can be categorized into three types of responses:
Secretion
Beta cells and other specialized cells have a regulated secretion rate, controlled by specific couriers. Molecules are stored in secretory vesicles until a signal (e.g., calcium levels) triggers their release.
Proliferation and Cell Development
- If a cell receives survival signals, it renews its structures
Hematological Disorders: Causes and Diagnostic Tests
Pernicious Anemia: Causes and Lab Findings
Pernicious anemia is a type of megaloblastic anemia caused by vitamin B12 deficiency, primarily due to autoimmune destruction of gastric parietal cells, leading to a lack of intrinsic factor (IF). Intrinsic factor is necessary for vitamin B12 absorption in the ileum. In addition to IF antibodies, some individuals produce antibodies against the B12-IF complex, further impairing B12 absorption. This results in defective DNA synthesis in erythroid precursor
Read MoreEnzymes and Nucleic Acids: Essential Biomolecules
Enzymes
Concept: Enzymes are usually proteins that specifically catalyze certain biochemical reactions by binding to the molecule or metabolite that is going to transform, the substrate.
Chemical Nature: Some protein enzymes are not exclusively proteins but are associated with other molecules. The nature of these molecules depends on the enzyme’s activity. These associations are called conjugated enzymes or holoenzymes. Holoenzymes are composed of cofactors and the protein part of the enzyme, the
Read MoreHuman Blood, Lymphatic, and Urinary Systems: Composition and Functions
Blood Composition and Functions
Blood constitutes 8% of our body weight. It consists of blood plasma and cellular components suspended in plasma.
Plasma
Plasma is a liquid composed mostly of water, minerals, glucose, proteins (fibrinogen, albumin, and globulin), and other substances such as vitamins and hormones.
Cellular Components
The cellular component constitutes about 40% of the blood. This volume remains constant and is called hematocrit. Its decrease indicates anemia. There are three types:
- Red
Human Senses: How We Perceive the World
How Do We Hear?
- An object vibrates.
- The air particles are pushed, creating sound waves.
- The outer ear picks up these vibrations and directs them to the middle ear, specifically the eardrum.
- In the middle ear, vibrations are amplified and transmitted to the inner ear.
- In the inner ear, hair cells (cilia) accumulate and transmit electrical impulses to the brain.
Diseases of the Ear
- Otitis: Inflammation of various parts of the ear, often caused by bacterial or fungal infections.
- Deafness: The diminution
Arterial and Venous Systems: Anatomy and Relationships
Arterial System
Radial Artery Branches
- Recurrent radial artery
- Muscular artery
- Palmar carpal branches
- Superficial palmar branch
- Principal artery of the thumb
- Dorsal carpal branch
- Artery of the first dorsal metacarpal space
Ulnar Artery
- More voluminous than the radial artery
- From the ulnar fossa
- Inferior and medial
- Passes the flexor retinaculum
- Forms the palmar arch
Ulnar Artery Branches
- Recurrent ulnar artery
- Common interosseous artery (anterior and posterior)
- Muscular branches
- Palmar carpal branch
- Dorsal carpal branch
- Deep