exam 3

osteoclasts secrete acids and enzymes

acids break down hydroxyapatite

enzymes break down osteoids

the osteocyte dies and releases calcium and phosphate back into the blood

bone resorption increases blood calcium and blood phosphate levels towards the normal range

the blood releases calcium and phosphate into the osteoblast cell which produces osteoids (strength) and hydroxyapatite (hardness), they mix and calcify then stick onto the osteoblast and the osteoblast turns into an osteocyte

bone production decreases blood calcium and blood phosphate levels towards the normal range and allows the bone to store calcium and phosphate

osteoblasts take over when calcium and phosphate levels are high

calcium and phosphates move into the bone when osteoblasts produce bone

this decreases blood calcium and phosphate levels towards the normal range

osteoclasts take over when blood calcium and phosphate levels are low

calcium and phosphates move into the blood when osteoclasts resort bone

this increases blood calcium and phosphate levels toward the normal range

uses the parathyroid hormone

red blood cell production, white blood cell production, and platelet production occurs in the sternum, ribs, vertebrae, clavicle, skull, and long bones

bone growth occurs near the diaphysis , occurs only in long bones

resting cartilage contains randomly arranged chondrocytes that anchor epiphyseal line to the epiphysis

proliferation contains chondrocytes arranged in columns which secrete collagen, proteoglycans, they divide into the zone of hypertrophy

the zone of hypertrophy is where chondrocytes mature and get bigger which begins cell death, chondrocytes continue to secrete collagen and proteoglycans as well as calcium phosphate and chondrocytes push into the zone of calcification

the zone of calcification is where chondrocytes die which leaves a voided space where osteoblasts enter and turn into osteocytes

growth and thyroid hormones promote bone production which increases chondrocyte and osteoblast mitosis and protein synthesis

sex hormones produce bone production and promote death of osteoclasts

parathyroid hormones promotes bone resorption, increased PTH causes more bone resorption

calcium is responsible for calcification of osteoblasts and chondrocytes

vitamin d is necessary for normal absorption of calcium and the production of hydroxyapatite

vitamin c is needed for synthesis of collagen which is needed to calcify osteoblasts and chondrocytes and low vitamin c in children can cause issues with bone growth

exercise puts stress on bones which promotes bone production

osteoporosis

decrease in bone density, decrease in osteocytes

caused by low blood calcium, aging, hormonal imbalances, lack of vitamin d

bones break more easily

osteopenia

decrease in bone density

pre-osteoporosis

same causes

osteomalacia/ rickets

decrease in hardness of bone, decrease in hydroxyapatite

caused by lack of vitamin d

can lead to bone deformity

peak bone mass is the greatest bone density during a lifetime usually achieved by 30 years old

affected early in life by hormones, nutrition, and lifestyle

amount of bone produced is greater than the amount absorbed

osteoblast activity is higher than osteoclast activity

loss of bone after peak is about 1% per year

amount of bone resorbed ends up greater than amount of bone produced meaning osteoclast activity is higher than osteoblast activity

menopause affects bone loss in females 3x more than a males span

skin protects from cuts, pathogens, toxic substances

loss of skin tissue leads to infections

prevents loss of interstitial fluid, loss of skin tissue leads to interstitial fluid loss which would lead to loss of fluid from blood

protects from UV rays

melanin absorbs UV rays that can damage DNA, protein and membranes

UV rays increase production of free radicals which damage the same things

melanocytes make up 10% of the stratum basale and contain tyrosinase which is converted into dopamine , dopamine is converted into melanin

dark skinned people have higher tyrosinase activity

albinism is a genetic condition that affects tyrosinase production, melanocytes can’t produce melanin

vitiligo is caused by autoimmune destruction of melanocytes which causes pale areas of skin

dermis is composed of collagen and elastic fibers, moss or damage of collagen or elastic fibers cause wrinkles

UVA penetrates dermal layer but UVB cannot

SPF 15: 1/15 93%

SPF 30: 1/30 97%

SPF 50: 1/50 98%

vitamin d production converts 7-dehydrocholesterol into cholecalciferol when exposed to 60 minutes of UVB a week, longer for dark skin

cholecalciferol circulates liver and converts to calcidiol

calcidiol circulates kidneys and forms vitamin D3

temperature regulation occurs via blood vessels in the dermal layer, blood vessels dilate when body temperature increases, blood vessels restrict when body temperature decreases

sweat is constantly produced to keep the body cool

high levels of Na+ and Cl- can indicate cystic fibrosis

pilocarpine sweat test measures Cl- concentration

hair responds to light pressure

merkels disk responds to light pressure

meissners corpuscle responds to light pressure and vibration

pacinian corpuscle responds to deep pressure

ruffinis corpuscle responds to skin stretch

free nerve endings respond to pain, temp, itch, and tickle

burns

head - 9%

front torso - 18%

back torso- 18%

entire leg- 18%

entire arm- 9%

genitalia- 1%

first degree- partial thickness, epidermis, won’t blister, heals naturally

second degree- partial thickness, epidermis and dermis, often will blister, will heal naturally

third degree- full thickness, epidermis and dermis, life threatening, skin graft or homograft

psoriasis- inflammation red and silver lesions, itchy, autoimmune damage, immunosuppressive medications, anti inflammatory creams

dermatitis- inflammation red lesions, itchy, allergic reactions, anti inflammatory medications, antihistamine medications

urticaria- inflammation of blood vessels, itchy, allergic reactions, resolves itself

dermatophytosis- ringworm, athletes foot, caused by fungus, contagious, anti fungal medication and creams

impetigo- lesions around mouth or nose, caused by bacteria, contagious, antibiotic medications and creams

warts- elevated skin lesions, abnormal skin cell division, caused by HPV, contagious, cryotherapy or salicylic acid

shingles- red swollen vesicles, caused by chickenpox virus, compromised immune system, contagious, anti viral medication or anti inflammatory medications

herpes- blistering of skin, caused by HSV, 75% have oral, 30% have genital, contagious, anti viral medication and lysine

brittle nails- due to cold dry conditions or too much water or thyroid disease

yellow nails- due to dermatophytosis or pulmonary disease or diabetes

white spots- due to trauma to nail body or zinc deficiency

pitting- due to psoriasis beneath nail body

concave- due to iron deficiency

pale- due to aging, anemia, cardiovascular disease or liver disease

dark vertical lines- due to trauma or melanoma