CH 7 Lecture Anatomy and Clinical Manifestations of the Integumentary System Flashcards

Integumentary System, Injections, and Skin Pigmentation

  • Needle Angles for Injections

    • Transdermal (Intradermal) Injections: These are administered at a very shallow angle, nearly 5∘5^{\circ}. The needle essentially spreads out against the skin rather than penetrating deeply.

    • Subcutaneous (SubQ) Injections: These needles enter the adipose (fat) layer. Typical medications administered this way include:

      • Heparin.

      • Peptides.

      • Insulin (described as hypodermal or subcutaneous).

  • Melanocytes and Melanin Function

    • Melanocytes: Found at the bottom of the skin tissues. These cells produce melanin, which is responsible for skin pigmentation.

    • Protection from Ultraviolet (UV) Energy: Internal organs do not have protective layers against UV. Without skin and melanin, UV radiation would "fry" and damage organs.

    • Mechanism of Melanin: Dark surfaces (melanin) tend to trap energy and then bounce it off (unlike light surfaces that let it penetrate deeper), preventing UV from entering the skin and damaging internal structures.

    • Tanning: A tan occurs when the skin is "frying" or being exposed to sun; the skin produces more melanin to protect the body from further UV damage.

  • Skin Color Variations and Genetics

    • The Equator: Countries near the Equator are hotter and receive stronger sun, leading to darker skin genetics for UV protection.

    • Northern Regions: In areas like the North Pole, skin is lighter because sun exposure is less intense.

    • Albinism: A condition where the body does not produce melanin. These patients have no color in their hair, eyelids, or lips and must avoid sun exposure entirely.

    • Vitiligo: A condition (or malfunction) where melanocytes stop working in certain areas, resulting in white drug pigmentation spots. It is not necessarily a disease or cancer, and causes can include:

      • High stress levels.

      • Hormonal imbalances.

      • Dietary factors.

Clinical Indicators and Metabolic Health

  • Color Changes and Systemic Issues

    • Cyanosis: A bluish discoloration of the skin caused by hypoxemia (low oxygen in the blood).

    • Ischemia: Pain caused by restricted blood flow. Examples include:

      • Feet "falling asleep" resulting in ischemic pain.

      • Chest Ischemia: Associated with high cholesterol and risk of heart attack (Myocardial InfarctionMyocardial\,Infarction).

  • Jaundice and Organ Dysfunction

    • Definition: A buildup of bilirubin in the body resulting in yellow skin and yellow sclera (the white of the eyes).

    • Liver Source: Problems like Cirrhosis are often irreversible and prevent the liver from performing essential functions.

    • Gallbladder Source: Gallstones can block the biliary duct, causing bilirubin to accumulate and be regurgitated back into the bloodstream.

    • Checking for Jaundice: Besides the sclera, practitioners should check the gums and the palms of the hands (especially in patients with darker skin tones).

  • Liver Functions

    • Protein synthesis (damage leads to bleeding and protein deficiency).

    • Storage of vitamins and minerals.

    • Glycogen storage and regulation.

Nail Assessment and Glandular Function

  • The Capillary Refill Test

    • Procedure: Push down on the nail until it turns white (pushing blood out), then release.

    • Standard: The nail should turn red (return of blood) within 3 seconds3\,seconds.

    • Clinical Significance: If refill takes longer than 3 seconds3\,seconds, it indicates a weak heart or heart failure, as the heart is not pushing blood efficiently to the extremities.

  • Nail Pathologies

    • Brittle/Shaking Nails: Often a sign of lack of nutrients, specifically Vitamin B12B_{12}.

    • Clubbing: Caused by chronic cyanosis or hypoxia. Capillaries in the fingers grow larger to try and capture more oxygen. This condition is generally irreversible and indicates long-term heart or respiratory failure.

  • Types of Glands

    • Sebaceous Glands: Pores that can become blocked. Oil turns black when it oxidizes, creating blackheads.

    • Apocrine Glands: Located in the armpits and groin. These become active during puberty. They produce a stickier sweat that traps bacteria, leading to body odor.

    • Eccrine Glands: Regular sweat glands (sudorific glands) used for cooling; the sweat is not typically sticky or odorous.

    • Modified Glands:

      • Ceruminous Glands: Produce earwax (CerumenCerumen).

      • Mammary Glands: Produced modified sweat in the form of milk.

Thermoregulation and Early Life

  • The Hypothalamus

    • The "Thermostat" of the brain.

    • Vasodilation: Dilates arteries when the body is hot to release heat (skin becomes flushed/red).

    • Vasoconstriction: Constricts arteries when cold to conserve heat (skin becomes pale) and push blood to the core.

  • Heat Production and Loss

    • Resources for Heat: Muscles (shivering), the Liver, and Endocrine glands. The Thyroid gland regulates metabolism and energy creation.

    • Hypothyroidism: Symptoms include being always tired, gaining weight, and feeling cold.

    • Mechanisms of Heat Transfer:

      • Radiation: Heat leaving the body into a cold environment (e.g., space or a cold room).

      • Conduction: Heat transfer through direct contact (e.g., a metal cooling blanket pulling heat away).

      • Convection: Heat loss via moving air (e.g., a fan).

      • Evaporation: Heat loss that only occurs when sweat evaporates off the skin.

  • Neonatal Thermoregulation

    • Vernix: A white fat layer that protects fetal skin from deteriorating in the amniotic fluid sac.

    • Brown Fat (Adipose Brown Tissue): Used for "non-shivering thermogenesis." Newborns lack the muscle tone to shiver; instead, they break down brown fat to produce heat.

Medical Emergencies: Burns and Heat Stroke

  • Heat Stroke

    • Occurs when vessels lose so much fluid through sweat that they shrink and narrow.

    • This prevents blood from reaching the brain, leading to a "stroke" caused by water loss rather than a clot.

  • Hypothermia

    • Defined as the body temperature dropping below 95∘F95^{\circ}F. (Normal is ≈98.6∘F\approx 98.6^{\circ}F).

    • Below 95∘F95^{\circ}F, organs shut down, leading to seizures or non-responsiveness.

  • Burn Classification

    • First-Degree: Affects the first layer of skin; hot and red.

    • Second-Degree: Affects the dermis (second layer) and is characterized by the presence of blisters. Never pop blisters due to infection risk.

    • Third/Fourth-Degree: Deep tissue damage.

  • Rule of Nines (Surface Area Estimation)

    • Face (Front and Back): 9%9\% (4.5%4.5\% for just the face/front).

    • Chest/Torso (Front and Back): 36%36\% (18%18\% front, 18%18\% back).

    • Arms: 9%9\% each (divided into 4.5%4.5\% for forearm/upper arm partitions).

    • Legs: 18%18\% each (9%9\% front, 9%9\% back).

    • Perineum: 1%1\%.

  • Burn Complications and Treatment

    • Carbon Monoxide Poisoning: In fires, this (and CO2CO_2) is often more lethal than the flames, as it stops breathing and causes loss of consciousness.

    • Eschar: Dead, burnt tissue that can act as a tourniquet. If it burns around the chest (circumferential), it prevents the chest from expanding, making breathing impossible. Surgeons must cut the eschar to allow circulation and chest movement.

    • Dehydration: The primary cause of death in burn patients. Burned capillaries leak fluid rapidly.

    • Prioritization (ABCs):

      1. Airway: Check for obstructions (like phlegm or eschar-related constriction).

      2. Breathing: Ensure oxygenation (O2 SaturationO_2\,Saturation).

      3. Circulation: Immediate hydration via IV fluids is critical in the first 24 hours24\,hours.

    • Antibiotics: Usually administered after the initial stable period (24 to 72 hours24\text{ to }72\,hours).