Notes, summaries, assignments, exams, and problems for Biology

Atherosclerosis: Pathogenesis & Complications

A chronic inflammatory disease of medium and large arteries, caused by endothelial injury and lipid accumulation.

Key Risk Factors:

• Hypertension
• Hyperlipidemia
• Smoking
• Diabetes

Lesions evolve from fatty streaks → fibrous plaques → complicated plaques.

Common Complications:

• Myocardial Infarction (MI)
• Stroke
• Aneurysm
• Peripheral Artery Disease

Histologically, it shows lipid cores, calcification, and fibrous caps.

Hypertensive Disease: Organ Damage & Malignant Forms

Chronic blood pressure (BP) elevation causes vascular and organ damage.

Consequences Include:

• Arteriolosclerosis
• Left Ventricular (LV) hypertrophy
• Stroke
• Chronic Kidney Disease

Malignant hypertension (diastolic BP >120 mmHg) causes fibrinoid necrosis... Continue reading "Essential Pathology Topics: Systemic Diseases & Neoplasms" »

First Stage: Gum Pad (Birth to 2 Years)

This stage lasts from birth until the completion of the deciduous maxillary gum pad.

• Maxillary Gum Pad: Horseshoe shape.
• Mandibular Gum Pad: U shape.
• Transverse Division: Elevated ridges are divided into segments for future deciduous teeth.
• Lateral Sulcus: Located distal to the canine area.

Gum Pad Occlusion

Gum Pad at Rest: The pads are not in contact, and the tongue is projecting.

Occlusal relationships are described in three dimensions:

1. Anteroposteriorly (Overjet): Anterior overjet; the mandibular lateral sulcus is posterior to the maxillary.
2. Vertically: Anterior open bite; posterior segments (Segment D) touch.
3. Transversely: The maxillary gum pad is wider than the mandibular (resulting in overjet).

Second Stage:

To sort the diversity of life using a rating system. Kingdom, phylum. sub class, super, order, sub groups, sub, genus, species, sub. Hierarchical binomial nomenclature, the greater the taxa categories. To reconstruct the phylogeny of a group uses a character that varies among members (ancestral character.) Is also used to compare outgroup (outgroup ) This is phylogenetically close, but not part of the study group. For any phylogenetic reconstruction we need to consider the characters that we use in our analysis and determine which is the primitive condition that presents the common ancestor of several. In this sense, we use the apomorphies that
refer to a derived or specialized character. In contrast, plesiomorphic, is a primitive character.

Common Oral Benign Lesions and Tumors

6. Peripheral Giant Cell Granuloma (PGCG)

Reactive lesion.

Key Features:

• Prevalence: More common in females and older individuals.
• Site: Exclusively on the gingiva or alveolar mucosa.
• Etiology: Local irritation or trauma.

Clinical Characteristics:

• Color: Dark red.
• Surface: Often hemorrhagic and may be ulcerated.
• Appearance: Sessile or pedunculated mass.

Radiographic Features (X-ray):

• May show superficial bone resorption, sometimes described as "saucerization" or a "cupping effect".
• Can appear as an ill-defined radiolucent (RL) area if bone is involved.

Histopathology:

Characterized by three zones:

1. Zone of Hyperplastic Stratified Squamous Epithelium: Often shows acanthosis and hyperkeratosis.
2. Giant Cell-Free Zone: A band

Neonatal and Pediatric Respiratory Disorders

An analysis of common respiratory conditions affecting newborns, including Respiratory Distress Syndrome (RDS), Transient Tachypnea of the Newborn (TTN), Meconium Aspiration Syndrome (MAS), Bronchopulmonary Dysplasia (BPD), Apnea of Prematurity, Congenital Diaphragmatic Hernia, and Congenital Heart Disease.

Respiratory Distress Syndrome (RDS)

RDS, also called hyaline membrane disease, is related to prematurity. The incidence increases with decreasing gestational age in the infant.

Major Factors in Pathophysiology

• Qualitative surfactant deficiency
• Decreased alveolar surface area
• Increased small airway compliance
• Presence of the ductus arteriosus

Clinical Manifestations

• Tachypnea
• Worsening retractions
• Paradoxical

Full Crown Veneer

Indications:

• Extensive destruction from caries or trauma
• Endodontically treated teeth
• Existing restorations
• Correction for occlusal plane

Contraindications:

• Less than maximum retention
• Esthetics

Advantages:

• Strong
• High retentive quality
• Easy to obtain
• Adequate resistance form

Disadvantages:

• Removal of large amount of tooth structure
• Adverse effect on tissues
• Vitality testing not readily feasible
• Display of metal

Porcelain-Fused-to-Metal (PFM) Crown

Indications:

• Esthetics if all-ceramic is contraindicated
• Gingival involvement

Contraindications:

• Large pulp chamber
• Intact buccal wall

Advantages:

• Superior esthetics compared to complete cast crown

Disadvantages:

• Removal of substantial tooth structure
• Subject to fracture
• Difficult to obtain accurate occlusion
• Shade

Cranial Synchondroses and Closure Times

Synchondroses are temporary cartilaginous joints crucial for craniofacial growth:

1. Spheno-occipital: Located between the occipital and sphenoidal base. Closes at 18–20 years old.
2. Inter-sphenoidal: Located between the anterior and posterior sphenoid. Closes before birth (prenatally).
3. Spheno-ethmoidal: Located between the sphenoidal and ethmoidal bones. Closes at 5–7 years old.
4. Intra-occipital: Located inside the occipital bone. Closes at 3–5 years old.

Etiology of Local Malocclusion

Local factors contributing to malocclusion are categorized as Hereditary, Acquired, or Other:

• Hereditary Manifestations:
  • Skeletal manifestation
  • Soft tissue manifestation
  • Dental manifestations
• Acquired Factors:
  • Trauma (Macro trauma,

Biodiversity Origins: Early Theories

Fixist Theory: Species Immutability

Proposes that species are immutable and have remained unchanged throughout time. Variations include:

• Creationism

  The belief that living things were created by a divine entity. This idea is largely rejected by the scientific community.

• Intelligent Design

  A creationism movement asserting that a creative intelligence is responsible for the complexity of the universe and life. Proponents argue that some biological characteristics are too intricate to have arisen from natural processes, a claim widely considered pseudoscience.

• Catastrophism

  Proposed by Georges Cuvier, this theory suggests that Earth has experienced several catastrophic events, leading to the extinction of species and

Human Body and Homeostasis

Cells and Their Functions

Cytoplasm: The material between the plasma membrane and the nucleus, composed of cytosol (largely water with dissolved proteins) and cytoplasmic organelles.

• Mitochondria: Provide ATP (energy).
• Ribosomes: Sites of protein synthesis.
• Endoplasmic Reticulum: Manufactures proteins and catalyzes reactions.
• Golgi Body: Concentrates and packages proteins.
• Lysosomes: Contain digestive enzymes; degrade unwanted substances.
• Cytoskeleton: Provides structural support.
• Nucleus: Control center of the cell; contains genes.
• Centriole: Plays an active role in cell division.
• Microvilli: Increase surface area for absorption.
• Vacuole: Membrane-bound organelle that stores and excretes substances.

Plasma Membrane: Separates... Continue reading "Human Body Systems: A Comprehensive Overview" »

The Menstrual and Ovarian Cycles

Menstruation: This phase begins on the first day of the cycle and lasts 5 to 7 days. If fertilization does not occur, the corpus luteum breaks down and stops producing progesterone. This causes the endometrium to shed, along with the oocyte, resulting in menstruation. If fertilization occurs, the embryo produces a hormone similar to LH (Luteinizing Hormone) to keep the corpus luteum active. It continues producing hormones, preventing menstruation. The oocyte is fertilized and completes oogenesis.

Proliferative Phase: This starts after menstruation and lasts until ovulation. Estrogens from the ovarian follicle stimulate the thickening of the endometrium and the growth of blood vessels.

Secretory Phase: This occurs... Continue reading "Menstrual and Ovarian Cycle Phases and Hormonal Changes" »