Feb 19 notes part 1

Announcements

Date: March 3 at 3 PM
Overview: Physiology students will design a lab practical for you, allowing participants to engage in a hands-on experience that reflects the actual lab practical environment, enhancing practical skills and understanding.

Overview: Attending tutoring sessions will provide opportunities for extra credit, contributing positively to your overall academic performance. These sessions may cover material that reinforces course concepts, aids in exam preparation, and clarifies difficult topics.

Definition: The hypodermis is the deepest layer of the integumentary system, primarily composed of adipose connective tissue.
Thickness Variability: Its thickness varies by body area; it serves distinct functions depending on its location.
- Example: Minimal adiposity, such as in the front of the shin (no hypodermis), contrasts with areas of thick adipose tissue, like the abdominal region (belly), where it provides more energy storage and insulation.

Men: Typically have a thicker hypodermis in the back, stomach, and neck areas.
Women: Generally, exhibit a thicker hypodermis in thighs, glutes, and breasts, which is often linked to reproductive and hormonal functions.

Energy Storage: Serves as a reserve of energy, critical for metabolism and energy balance.
Physical Cushioning: Provides protection against external physical impacts and enhances comfort while sitting or lying down.
Insulation: Retains body heat, helping to maintain core temperature, especially in colder environments.

Performing sit-ups does NOT specifically burn belly fat; instead, fat is burned evenly from all over the body during exercise.
Effective fat loss requires engaging in consistent cardiovascular activities such as running, swimming, or cycling to maximize caloric burn and improve overall fitness.

Overview: There are no distinct types of fat in adults; all forms of adipose tissue serve similar functions in energy storage and insulation.
Cellulite: Commonly misinterpreted as a special kind of fat, cellulite is simply adipose tissue that appears differently due to genetic storage patterns and is more prevalent in women due to variations in fat distribution.
Cultural Context: The popularity of the term “cellulite” originated in the 1920s alongside rising body sizes and advertising campaigns that exacerbated insecurities related to body image.

Basal Cell Carcinoma (BCC):
- Incidence: Most common type of skin cancer, accounting for around 70% of all cases.
- Origin: Arises from keratinocytes in the stratum basale layer of the epidermis.
- Metastasis Risk: Rarely metastasizes; primarily linked to prolonged exposure to ultraviolet (UV) radiation. Each instance of sunburn effectively doubles the risk of developing BCC over time.
Squamous Cell Carcinoma (SCC):
- Incidence: Represents about 25% of skin cancers.
- Origin: Develops from keratinocytes in the stratum spinosum.
- Metastasis Risk: Less frequent to metastasize but documented cases exist; also associated with sunburns that double the risk.
- Prognosis: 99% curable with timely intervention and treatment.
Melanoma:
- Incidence: Considered the most dangerous type of skin cancer; mortality rates are significantly higher.
- Origin: Arises from melanocytes, responsible for pigmentation in the skin.
- Metastasis Risk: Easily metastasizes to other parts of the body; not solely a result of UV light exposure, often linked to genetic factors as well.
- Diagnosis: Diagnosed using the ABCDE method:
  - Asymmetry: Irregular shapes.
  - Borders: Undefined or scalloped edges.
  - Color: Presence of multiple colors or uneven coloration.
  - Diameter: Larger than a pencil eraser (6 mm).
  - Evolving: Changes in size, shape, or color over time.

First-Degree Burns:
- Overview: Affect only the epidermis (e.g., mild sunburns).
- Characteristics: Generally harmless but can increase the risk of skin cancer over time due to UV exposure.
Second-Degree Burns:
- Overview: Damage extends into the dermis layer, often resulting in blisters and significant pain.
Third-Degree Burns:
- Overview: Full-thickness burns that affect all skin layers, leading to more severe consequences.
- Risks: Increased risk of dehydration and infection; often require skin grafts for effective healing.

Bleeding: Initial response to injury where blood vessels rupture, leading to blood loss.
Cleaning: Macrophages and other immune cells work to clear debris and reduce infection risk.
Collagen Production: Fibroblasts create a scaffold for healing, depositing collagen to strengthen the area.
Epidermis Growth: Over the course of approximately four weeks, the epidermis regenerates beneath the scab, restoring skin integrity.

Overview: Chronic autoimmune condition primarily affecting keratinocytes in the skin, leading to patches of dead skin and severe itching.
Treatment: Often involves reducing immune system activity to manage symptoms, which can inadvertently impact the body’s ability to resist infection.

Definition: The main pigment affecting skin color, with varying concentrations among different individuals.
Pheomelanin: Contributes a red or yellow tint, commonly found in hair and specific skin areas.
Keratin: Provides yellow/orange hues, with higher concentrations observed in certain populations, influencing overall skin tone.
Hemoglobin: Blood flow indicator; visible through thinner skin areas, altering the perception of skin tone based on vascular health and blood flow activity.