Anatomy

Question 1

Function of the Integumentary System

Answer 1

1. protection
2. waste excretion
3. body temp
4. production of melanin
5. production of keratin
6. synthesis of Vitamin D₃
7. fat storage
8. sensation
9. Immune response: innate, inflammation

Question 2

Layers of the Skin

Answer 2

• Epidermis
  
  • stratum basale
  • stratum spinosum
  • stratum granulosum
  • stratum lucidum
  • stratum corneum
• Dermis
  
  • papillary layer
  • reticular layer
• Subcutaneous/Hypodermis

Question 3

Epidermis general

Answer 3

• keratizined stratified squamous epithelium
  
  • keratin and related proteins are tough, fibrous, and waterproof
• glycoproteins: are waterproof, are a film of lipids
• is avascular → receives all of its nutrients via diffusion from the underlying connective tissue

Question 4

Keratinocytes

Answer 4

• majority (99.9%) of skin cells
• keratin = water resistant, tough, fibrous protein related to intermediate filament protein

Question 5

Langerhans Cells

Answer 5

• antigen presenting cells (immune cells) located in the epidermis
• engulf pathogens and cellular debris
  
  • present antigens in skin to T-cells
  • can migrate to nearest lymph nodes

Question 6

Melanocytes

Answer 6

• pigment producing cells located near basal layer of epidermis
  
  • they reach out into the upper layers
• melanin: absorbs UV radiation, which helps to prevent DNA and tissue damage
  
  • also determines skin color
    
    • eumelanin: brown-black
    • pheomelanin: red-yellow

Question 8

Skin Color

Answer 8

• Melanin:
  
  • eumelanin: brown-black
  • pheomelanin: yellow-red
• Bilirubin levels: yellow/jaundiced
• carotene (dietary): orange-yellow
• blood flow:
  
  • increased circulation = pink/red
  • decreased circulation = pale/white
  • lack of oxygen = cyanotic

Question 9

Thick Skin vs Thin Skin

Answer 9

• Thick skin:
  
  • has all 5 layers including the stratum lucidum
  • thicker layer of stratum corneum
  • location: palms of hands and feet
  • epidermal ridge: finger print
• Thin Skin:
  
  • only 4 layers
  • location: everywhere else on the body

Question 10

Dermis General

Answer 10

• strong, elastic, flexible layer filled with blood vessels and sensory receptors
• 1-4mm thick
• made up of connective tissue, blood vessels, lymphatics, sensory cells and nerves
• 2 layers:
  
  • papillary layer
  • reticular layer

Question 11

Papillary Layer

Answer 11

• part of dermis
• areolar connective tissue
• dermal papillae–form epidermal ridges (rete pegs)
• blood vessels, lymphatic vessels, nerves, sensory cells

Question 12

Reticular Layer

Answer 12

• deepest layer of the dermis
• dense irregular connective tissue
• contains: blood vessels, lymphatic vessels, nerves, sensory cells, base of hair follicles and glands

Question 13

Cells found in the dermis

Answer 13

1. Fibroblasts
2. Mast Cells
3. Macrophages

Question 14

Fibroblasts

Answer 14

• located in the dermis
• secrete connective tissue matrix throughout the dermis
• primary cells in the dermis
• surrounding by matrix (made of collagen and elastin)

Question 15

Mast Cells

Answer 15

• immune cells located in the dermis
• contain granules of histamine and heparin
• vasoactive and pro-inflammatory mediators
• coated with IgE → allergy and anaphylaxis reactions

Question 16

Dermal Blood Flow

Answer 16

• blood supply is only in the dermis
• under the control of alpha-adrenergic receptors
  
  • activation of the sympathetic nervous system will cause vasoconstriction of these blood vessels
• Vasodilation = release heat
• vasoconstriction = conserve heat

Question 17

Subcutaneous Layer of the Skin

Answer 17

• deep to the dermis
• contains adipose and some aerolar connective tissue
  
  • anchors skin to underlying muscle
  • allows skin to slide with relative ease
  • energy reserve, insulation, shock absorber

Question 18

Answer 18

Question 19

Hair Follicles and Hair Definition

Answer 19

• Hair Follicle:
  
  • tiny hair producing organ that extend into the deep dermis and even into the subcutaneous layers
• Hair:
  
  • non-living keratinized structure
  • function:
    
    • insulate the skull
    • keep out foreign particles
    • are sensory receptors

Question 20

Arrector Pili

Answer 20

• muscle that causes goose bumps
• involuntary, smooth muscle that attaches to the hair follicle
  
  • when it contracts, it pulls on the follicle and raises the hair up

Question 21

Sebacious Gland

Answer 21

• secrete sebum into the hair follicle
• secrete oil onto the skin surface
• stimulated by androgens,
  
  • get bigger during puberty
• keep hair and skin supple
• kill bacteria
• location: face, chest, and back
  
  • some modified glands on eyelids, lips, nipple, glans penis, prepuce

Question 22

Suderiferous Glands

Answer 22

• aka sweat glands
• eccrine/merocrine glands:
  
  • coiled tubular gland, duct opens to the skin surface
  • watery secretion →perspiration (cooling effect)
  • location:
    
    • widely distributed especially on hands, feet, and face
• apocrine glands: ducts that empty into hair follicles
  
  • location:
    
    • axillary and genital regions
    • produce milky sweat: water with lipids and proteins

Question 23

Location of Hyponychium, Eponychium, Paronychium

Answer 23

Question 24

Nail Structure

Answer 24

• Nail Plate:
  
  • free edge, nail body (lunula = thickened white)
  • nail root
• nail bed: under the nail body
• nail fold: over the nail root
• eponychium: (cuticle) margin of the nail fold
• hyponychium: under free edge
• paronychium: near sides of the nail plate

Question 25

Functions of Vitamin D

Answer 25

* calcium and phosphate homeostasis: * vitamin D = increased calcium and phosphate **absorption from small intestine** * with the help of **parathyroid hormone** * increases renal reabsorption of calcium * increases renal excretion of phosphate * enhances bone calcification, bone growth, bone remodeling * Other functions: * cell growth * immune function * neurologic function * reduction of inflammation

Question 26

Ergocalciferol

Answer 26

* vitamin D₂ * inactive precursor * can be given as a **supplement**

Question 27

Cholecalciferol

Answer 27

* vitamin D₃ * inactive precursor * can be given as a **supplement** * made in the **skin** * hydroxilated by the **liver** where it becomes **calcifediol** 25(OH)-vitamin D₃

Question 28

Calcifediol

Answer 28

* 25 (OH)- vitamin D₃ * an intermediate form with a long half life * travels the the blood stream where it can travel to the **kidneys** to get hydroxilated and transformed into active form * what we test for in lab tests

Question 29

calcitriol

Answer 29

* **1,25-dihydroxy-vitamin D₃** * active form of vitamin D

Question 30

To end up with 1,25(OH) Vitamin D₃

Answer 30

* requires: * 1. **sunlight** OR **supplementation** of ergocalciferol or cholecalciferol * AND functional activation of the **liver AND Kidneys**

Question 31

What can cause Vitamin D deficiency

Answer 31

* liver disease * kidney disease * intestinal malabsorption (Celiac's diseasem crohn's disease) * Lack of UV (B) exposure * we require 15-30 minutes/day

Question 32

Rickets

Answer 32

* in children (called **osteomalacia** in adults) * caused by: * lack of Vitamin D due to sunlight, dietary insufficiency AND/OR lack of calcium or phosphate * → **demineralization of bone** * Clinical presentation: * bone: tenderness, deformity, joint pain, increased risk of fracture * in children: growth problems, **varus deformity** (leg bowing), **"rickety rosary"** (costochondral swelling), lumbar lordosis, greenstick fractures * _muscle_: weakness/spasms or tetany * _neurological_: seizures * _cardiovascular_: cardiomyopathy * _other_: enlarged spleen and liver

Question 33

Dietary Sources of Vitamin D

Answer 33

* fatty fish and fish oil * beef liver, cheese, egg yolks * mushrooms * fortified foods * NOTE: all infant formula contains vitamin D → breastfed infants need to be supplemented

Question 34

Normal Serum Levels of Vitamin D

Answer 34

* \>/= 50nmol

Question 35

Recommended amount of Vitamin D

Answer 35