Skin & Endocrine Flashcards
Introduction to skin
What kind of organ is the skin?
It is considered the largest organ.
It is a sensory organ
Where is the thinnest skin found and measurement?
The eyelids only 0.1mm.
Where is the thickest skin found and how deep does it measure approximately?
The palms and soles of feet around 2mm.
What are the two types of skin?
1) Hirsute - thin, hairy skin which covers greater part of the body.
2) Glavrous - covers the surfaces of palms, soles and flexor surfaces.
Name the three layers of the skin and briefly mention what it is composed of.
Epidermis
- the superficial portion of the skin. Composed os epithelium tissue.
Dermis
- the deeper layer of the skin. Primarily composed of connective tissue.
Subcutaneous layer or hypodermic
- composed of areola and adipose tissue used for fat storage. It is an area of blood vessel passage and an area of pressure sensing nerve endings.
List the functions of the skin
PREMFAC
Protection - physical barrier to internal organs
- acid pH helps to prevent infection
Regulation of temerature - thermoregulation
- blood vessels constrict or dilate to
raise or lower body temperature.
Excretion - 400ml of water /day
- ammonia, CO2 and small amounts of
Sodium.
Movement - elastic & recoil properties if skin
Formation of Vit D - photochemical reaction in the skin produces ambit D essential for metabolism of calcium.
Absorption - topical medicine.
Cutaneous sensation - touch pressure
Temperature change
Pain
What is the first wound healing response?
Haemostasis - within minutes, platelets and fibrin are at the site of the wound.
What is the second stage of wound healing?
Inflammation- Neutrophils Macrophages and/ lymphocytes are at work.
What is the third stage of wound healing ?
Proliferation - fibroblasts, collagen and angiogenesis………
What is the fourth and last stage of normal wound healing?
Maturation - collagen remodelling & scar maturation.
What types of factors affect wound healing?
Systemic & local
Systemic - age, anaemia, nutrition, medication, systemic infections, temperature, chronic health problems e.g diabetes.
Local - blood supply, local infection, wound bed condition, size of wound.
Who are most at risk?
People who have ;
reduced movement.
Vascular damage.
Sensory impairment
Malnourished/ dehydrated
What is the normal blood similarity range?
257 and 295 mOsm/kg
What is the name if the receptor that measures similarity in blood and where is it found?
Osmoreceptors in the hypothalamus
What is the role of Antidiuretic hormone?
To increase permeability of the collecting duct and distil convoluted tubules. This is in the nephron for increased water reabsorbtion back to the bloodstream
What is the name of the hormone released to break down glycogen in the liver and where is it released?
glucagon
Released by the pancreas at the islet of Langerhans which is sensitive to glucose.
The alpha cells secrete glucagon when blood glucose is low.
What hormone is released when the blood glucose is high?
Insulin.
Released by the beta cells of the islet of Langerhans in the pancreas.
Name the major endocrine glands.
Hypothalamus
Pituitary gland
Pineal gland
Thyroid gland
Parathyroid gland
Thymus
Adrenal gland
Pancreas
Ovary - female
Testis - male
Name the 4 chemical classes of hormones
Peptide/ polypeptide
Amino Acid derivatives (amine)
Glycoproteins
Steroids
What is the role if carrier/blinding proteins?
- increase solubility of hormone in plasma
- increase half life
- readily accessible reserve
Do all hormones require a carrier protein to get to the target cell?
No.
Target cells contain what in their cell membrane for hormones to bind to?
Specific hormone receptors.
What type of hormone needs to bind to receptors ?
Water soluble of non soluble hormones.
Water soluble.
E.g insulin binds to tyrosine kinase at the cell membrane.
What do lipid soluble hormones bind to?
After diffusing across the hydrophobic and hydrophilic membrane, they bind to intracellular receptors.. either in the cytoplasm or in nucleus.
E g thyroid hormone enters nucleus and binds to a pre-bound receptor on DNA.
