Physiology of Integumentary System

Physiology of the integumentary system

dermatomes

temperature regulation

metabolic function with vitamin D

pathophysiology

• burns

• skin cancer

dermatomes

skin innervated by extensive network of nerves

one of these

• region of skin innervated by one sensory nerve

sensory signals

• carrying information from sensory organs

• skin to spinal nerve to spinal cord to brain

each region innervated by single spinal nerve

• except the fact

• cranial nerve V: trigeminal nerve)

• cervical, thoracic, lumbar

temperature regulation

skin helps to maintain normal body temperature

body temperature rises, homeostasis seeks to lower body temperature:

• blood vessels dilate

  • skin becomes red

  • heat releases through skin

• perspiration: sweat glands stimulated to release sweat

  • evaporative cooling

    • when water is heated it turns from liquid to vapor, takes heat away from the skin

perspiration

sweat glands stimulated to release sweat

leads to evaporative cooling

evaporative cooling

when water is heated it turns from liquid to vapor

takes heat away from skin

blood vessels dilate

in thermoregulation

makes skin become red, and heat releases through the skin

sensory signals

part of dermatomes

carrying information from sensory organs

skin to spinal nerve to spinal cord to brain

insensible perspiration and sensible perspiration

two types of perspiration in thermoregulation

insensible perspiration

happens before it is “sensed”

water continually diffusing through the skin

• through the epidermis and evaporates off the skin surface

accounts for about 500mL lost daily

• rises drastically if large surface area of stratum corneum is damaged (burn)

sensible perspiration

person senses they are sweating

water excreted through sweat glands

body temp cools

what happens in temperature regulation when…

• blood vessels constrict

• sweat glands stop producing sweat

• heat is maintained in the tissues

metabolic function vitamin D

• small amounts of sunlight are important for vitamin D production

• vitamin D3 = cholecalciferol

  • can also be absorbed in the diet

• cells of the epidermis

  • sunlight converts a steroid into vitamin D

• liver

  • vitamin D - intermediary product

• kidney

  • intermediary product calcitriol

Calcitriol

hormone

needed for absorption of calcium in the small intestine

needed for bone growth and maintenance

lack of vitamin D

abnormal bone development

inhibits bone maintenance at the tissue level

skin or diet production can cause lack of this..

rickets

seen in children lacking vitamin D

abnormal bone development

specifically with children

burns

can be classified in several ways

one method is through severity of bones

pathophysiology

first degree burn

superficial burns

damage only the epidermis

EX.) mild sunburn

second degree burn

partial thickness burns

damage to the epidermis and some or most of the dermis

skin turns red and forms blisters

painful

EX.) cooking injury, severe sunburn, exposure to fire

third degree burn

full thickness burns

damage to the epidermis, entire dermis, and slightly into the subcutaneous tissue

skin looks white or charred

NO sensation

EX.) scalding liquid, exposure to hot object for longer time, exposure to fire

fourth degree burn

damage to the epidermis, entire dermis, subcutaneous layer, and underlying tissue

loss of sensation

• so much damage that the pain receptors are gone

EX.) chemical, exposure to hot object for LONGER time, exposure to fire

skin grafting

necessary if skin is too severely damaged or if burn covers a large area

healthy skin is taken from a persons own body

grafted on top of damaged area

Why?

• decreased recovery time

• prevention of infection

• assisting in tissue repair

skin cancer

pathophysiology

most common form of cancer

chronic UV exposure

damage to the structure of DNA

• if DNA is damaged it cannot properly synthesize RNA or proteins

• leads to disruptions in cell life cycle

basal cell carcinoma and squamous cell carcinoma

two types skin cancer

most people survive if caught early

surgical removal

• remove cells, clear and border around it

malignant melanoma

skin cancer

extremely dangerous

cancerous melanocytes grow rapidly and can spread to the lymphatic system

survival rate depends on how early the cancer is caught

asymmetry, border, color, diameter, evolution

Skin cancer ABCDEs in order

asymmetry

one of the skin cancer ABCDEs

skin cancer tends to have an irregular pattern

one side does not match the other

border

one of the skin cancer ABCDEs

skin cancers - irregular or blurred borders

normal skin - clearly circular

uneven borders

color

one of the skin cancer ABCDEs

skin cancers - not uniform, combination of colors (black, brown, red, tan)

normal skin - uniform color

variety of colors

diameter

one of the skin cancer ABCDEs

skin cancers - more than 5mm

• larger than a pencil eraser is dangerous

evolution

one of the skin cancer ABCDEs

skin cancers - change in size, shape, and symptoms

• may start to bleed or become itchy

• elevation in another trait or new symptoms

white

what race is most likely to have skin cancer