Lecture 20 - Integumental System Flashcards
What are some general roles of skin
Sensation
Thermoregulation
Vitamin D absorption
Protection
What are skin appendages?
Nails
Hair
Breasts
What is the germ layer derivate of the skin?
Epidermis: ectoderm
Dermis: mesoderm
What is the epidermis made up of?
Keratin
Basal cells
Melanocytes
Describe the layers in the skin
Epidermis Dermis Subcutaneous tissue Deep fascia (Muscle Bone)
What is subcutaneous tissue made up of?
Fat
Fibrous strands
Describe subcutaneous fat distribution in males and females
Males: thighs, belly
Females: bottom, thighs, breasts, belly, back of neck
What is meant by ‘thick skin’, and what are the features?
This is the thick, hairless skin on the palms and soles of feet
What is the simian crease associated with?
Foetal alcohol syndrome
Downs’ syndrome
What is a general rule for skin surafce area percentages?
Rule of 9s Trunk: 18% Leg: 9% each Arms: 9% Head: 9% Genitalia: 1%
Why are skin tension lines important?
Scar will heal and appear better is the laceration is made across the skin tension line
Why is skin surface area important for burns victims?
The fluid loss and replacement is proportional to percentage of skin lost
What is the name of the hair + sebum gland?
Describe the structure of it
Where is it located?
Pilosebaceous gland
Hair and hair follicle attached to Arrector pilus muscle
Sebaceous gland further up the shaft of the hair
The hair follicle is in the dermis, and it extends out through the epidermis through the skin
Where is a sweat gland located?
In dermis, up our of the epidermis
What is the structure of the sweat gland?
Gland (dermis)
Duct
What is interesting, evolutionarily, about the finger nail?
It has migrated from the anterior to the posterior asspect
What is the special region in the mouth?
Mucocuaneous junction
Mucosa meets the skin
What is the structure of the nail bed?
Deep connective tissue
Describe the blood and nerve supply of the skin
Epidermis: avascular and aneural
Dermis: rich vascular and nervous innervation
Which receptors are present in the skin?
Mechanoreceptors: Meissner, Merkel, Pacini, Ruffini
Nociceptors
What are the different types of motor innervation of the skin?
Vasomotor: diameter of blood vessels
Sudomotor: sweat glands
Pilomotor: Arrector pili muscle
What are the names of the many regions of the skin that have sensory innervation? Give a precise definition
Dermatomes
A region of the skin innervated by a single segment of the spinal cord
Describe the pattern of the dermatomes of the body
Since we have limbs, the dermatomes have been pulled out onto the limb, and thus do not proceed directly down the trunk
Arm: C5-8 and T1-2 out along preaxial border, and back along postaxial border
Do dermatomes overlap?
Dermatomes do not overlap over the axis
However, they do overlap with adjacent dermatomes
Describe the overlapping of mechanoreceptors and nociceptors in dermatomes
The nociceptors overlap much more than the mechanoreceptors.
This ensures that when a dermatome is lost, nociception in that area will not be completely lost
Why is shingles interesting when looking at dermatomes?
The virus remains latent in the posterior root ganglion and then reawakens when the individual is immunosuppressed.
It comes down the nerve and produces symptoms only in the dermatome supplied by that posterior root ganglion.
Describe the regions of blood supply to the skin
The body is made up of angiosomes: regions that are supplied by a single artery and vein
