Lecture 7 - Integument Physiology 1 Flashcards
T/F: at every body orifice, the skin is continuous with the mucous membrane located there
True
What are the 3 layers of the skin
1 - Epidermis
2 -Dermis
3 - Hypodermis
what are the 4 distinct cell types within the epidermis
1 - Keratinocytes
2 - melanocytes
3 - Langerhans cells
4 - Merkel cells
Keratinocytes
specialized epithelial cell
Melanocytes
pigment cells
Langerhans cells
specialized macrophage (local immunity)
Merkel cells
specialized sensory cells
What regulatory role does the dermis play
regulation of cell growth, proliferation, adhesion, migration, differentiation, and wound healing
What insoluble fibers are found in the dermis
collagen, elastin, macromolecules
T/F: many of the functions of the skin are performed in the dermis
True
For some functional reasons, there is no subcutis in some areas. what are these areas?
Lip, cheek, eyelid, external ear, anus
the hypodermis is 90% ______
triglyceride
What are the 6 functions of the skin
1 - Physical barrier
2 - Immune defense against external threats
3 - metabolic functions
4 - Indicator
5 - Sensory perception
6 - Thermoregulation
Physical barrier
Exclusion of external injurious agents and retention of necessary water, electrolytes, etc.
Immune defense against external threats
external microorganisms with antimicrobial and antifungal properties
metabolic functions
storage of nutrients and fluid
excretion of waste byproducts
vitamin D metabolism
what is the active form of vitamin D
calcitriol (1,25 hydroxyvitamin D)
Summarize Vitamin D metabolism
1 - Vitamin D3 is formed from pro-D3 via pre-D3 on exposure to sunlight
2 - binding protein in plasma translocates D3 into circulation
3 - D3 is hydroxylated in the liver
4 - hydroxylated again in the kidneys to the final product
Indicator
general health or internal disease
camouflage
sexual dimorphism
olfactory cues
Sensory perception
Via Merkel cells and somatic sensory
How does the skin support thermoregulation?
supports haircoat
regulates the cutaneous blood supply
sweat gland functions
How does the body attempt to raise basal temperature?
piloerection (hair standing on end) for trapping air
vasoconstriction brings blood toward the core
shivering
breakdown of brown fat
What is the critical temperature?
the external temp at which internal heating mechanisms cannot maintain a constant body temp
Brown fat has an increased _______ and ______
blood supply; mitochondria
How does the body attempt to lower basal temperature?
vasodilation (brings blood closer to the skin for radiational loss of heat)
evaporative cooling
heat transfer from an animal to a cool surface is called
conduction
heat transferred from the animal to the environment
radiation
heat loss from the movement of air
convection
heat loss that occurs when water becomes a gas
evaporation
what environmental temperature rises respiratory rate in cats and dogs
cat: 90
dog: 81-84
what is respiratory alkalosis?
a. the dangerous lowering of CO2 in the body
b. disruption in the blood-gas equilibrium
c. both a and b
c
What animal produces watery saliva as an additional cooling mechanism
cats
