calcium endocrinology physiology

Question 1

what does aldosterone control

Answer 1

Na

K

Question 2

what hormones control calcium and phosphate

Answer 2

• parathyroid hormone
• calcitonin
• vitamin D

Question 3

is calcium concentration tightly controlled

Answer 3

yes very

Question 4

where is 99% of the calcium in the body

Answer 4

in crystalline form within the skeleton and teeth

Question 5

is free ECF calcium biologically active

Answer 5

yes

Question 6

roles of free ECF

Answer 6

• neuromuscular excitability
• excitation contraction coupling
• stimulus secreting
• maintenance of tight junction
• clotting of blood

Question 7

what does a fall in calcium do to muscles

Answer 7

causes over excitability of nerves and muscles

Question 8

what is hypocalcemia

Answer 8

low blood calcium

Question 9

what does a rise in cytosolic calcium within a muscle cause

Answer 9

contraction

Question 10

what does an increase in calcium into cells cause

Answer 10

release of secretory product by exocytosis

Question 11

what does increase in calcium into the pancreatic beta cell cause

Answer 11

insulin secretion

Question 12

does calcium aid in intercellular junctions

Answer 12

yes forms part holing it tightly together

Question 13

calcium in the blood acts as

Answer 13

co factor

Question 14

what does calcium in the blood lead to

Answer 14

clot formation

Question 15

what is calcium in bone and teeth essential for

Answer 15

structural and functional integrity

Question 16

CONTROL OF CALCIUM METABOLISM

Answer 16

CONTROL OF CALCIUM METABOLISM

Question 17

how is urinary excretion of calcium controlled

Answer 17

hormonally

Question 18

what serves as a large calcium reservoir

Answer 18

bone

Question 19

how is calcium homeostasis maintained

Answer 19

exchanges between bone and ECF

leads to modifications in urinary calcium

Question 20

how is calcium balance maintained

Answer 20

adjusting intestinal calcium absorption and urinary calcium excretion

Question 21

what is the primary regulator of calcium

Answer 21

parathyroid hormone

Question 22

what vitamin also helps maintain calcium

Answer 22

vitamin D

Question 23

what is another calcium influencing hormone

Answer 23

calcitonin

Question 24

when is calcitonin used

Answer 24

during extreme hypercalcemia

Question 25

PARATHYROID HORMONE

Answer 25

PARATHYROID HORMONE

Question 26

where is parathyroid hormone secreted from

Answer 26

parathyroid

Question 27

what are the parathyroid glands

Answer 27

4 rice grain sized glands

Question 28

where are parathyroid gland located

Answer 28

back surface of the thyroid gland - one in each corner

Question 29

is PTH essential for life

Answer 29

yes

Question 30

what is the overall effect of PTH

Answer 30

increase calcium concentration in plasma

Question 31

what does PTH prevent

Answer 31

hypocalcemia

Question 32

how long can you survive without PTH

Answer 32

few days

Question 33

BONE REMODELLING

Answer 33

BONE REMODELLING

Question 34

where is most of the bodies calcium

Answer 34

bone

Question 35

what does bone serve as

Answer 35

calcium storage depot

Question 36

is bone a living tissue

Answer 36

yes

Question 37

what is bone composed of

Answer 37

osteoid

Question 38

what is bone impregnated with

Answer 38

hydroxyapatite crystals

Question 39

where do the hydroxyapatite crystals in bone precipitate

Answer 39

around collagen fibres in the matrix

Question 40

is the bone always changing | yes or no

Answer 40

yes | constantly being remodelled

Question 41

how often is the skeleton completely regenerated

Answer 41

every 10 years

Question 42

what are osteoblasts

Answer 42

secrete extracellular or panic matrix

Question 43

what are osteocytes

Answer 43

retired osteoblasts

Question 44

what are osteoclasts

Answer 44

resorb bone in their vicinity

Question 45

what do osteoclasts actively secrete

Answer 45

hydrochloric acid that dissolves crystals and enzymes

Question 46

how do osteoblasts form cell

Answer 46

move into the cavity and secrete osteoid to fill in the hole

Question 47

are the rates of bone formation and respiration equal

Answer 47

yes

Question 48

where are osteoblasts derived from

Answer 48

stromal cells

Question 49

what do osteoclasts derive from

Answer 49

macrophages

Question 50

what does RANK ligand rev up

Answer 50

osteoclast action

Question 51

what does RANK ligand bind to

Answer 51

RANK

Question 52

what can osteoblasts secrete

Answer 52

osteoprotegerin (OPG)

Question 53

what does OPG bind to

Answer 53

RANKL

Question 54

what can stimulate OPG

Answer 54

oestrogen

Question 55

what helps maintain growing bones in kids

Answer 55

- growth hormone | - IGF-1

Question 56

what does stress cause in bone

Answer 56

favours bone deposition

Question 57

are the bones in athletes stronger

Answer 57

yes

Question 58

what happens to bone during prolonged bed rest

Answer 58

bone mass diminishes

Question 59

what is osteoporosis

Answer 59

reduction in bone mass

Question 60

PTH

Answer 60

PTH

Question 61

what does PTH do

Answer 61

promote calcium conservation

Question 62

can PTH promote bone dissolution

Answer 62

yes

Question 63

what can PTH do on the kidney

Answer 63

enhance activation of vitamin D

Question 64

PTH and the small intestine

Answer 64

increases both calcium and hydroxyapatite form the small intestines

Question 65

when does PTH secretion increase

Answer 65

when plasma calcium falls

Question 66

is calcitonin important in normal calcium metabolism

Answer 66

no

Question 67

what produced calcitonin

Answer 67

C cells

Question 68

what is the effect of calcitonin

Answer 68

decrease calcium movement

Question 69

does calcitonin have an effect on the intestine

Answer 69

no

Question 70

what does calcitonin protect against

Answer 70

hypercalcemia

Question 71

VITAMIN D

Answer 71

VITAMIN D

Question 72

what is vitamin D essential for

Answer 72

calcium absorption in the intestine

Question 73

how is vitamin D made

Answer 73

produced in the skin from a precursor related to cholesterol on exposure to sunlight

Question 74

is vitamin D active

Answer 74

no

Question 75

where is vitamin D active

Answer 75

firstly in liver then kidneys

Question 76

what is the end result of vitamin D activation

Answer 76

calcitriol

Question 77

what is the most dramatic effect of activated vitamin D

Answer 77

to increase calcium absorption in the intestine

Question 78

is most calcium absorbed or lost in the faeces

Answer 78

lost in the faeces

Question 79

does vitamin D have an effect on PTH

Answer 79

yes

Question 80

how does vitamin D exert its effects

Answer 80

by. binding to nuclear vitamin D receptor

Question 81

does vitamin D play an essential role in calcium homeostasis

Answer 81

no its too sluggish

Question 82

DISORDERS OF CALCIUM

Answer 82

DISORDERS OF CALCIUM

Question 83

what are the main disorders that affect calcium metabolism

Answer 83

too much or too little PTH

Question 84

what is excess PTH cause

Answer 84

hyperparathyroidism

Question 85

what is hyperparathyroidism caused by

Answer 85

tumour in one of the parathyroid gland

Question 86

symptoms of hyperparathyroidism

Answer 86

- reduced excitability of muscle - muscle weakness - decreased alertness - poor memory - depression - cardiac disturbance - thinning of bone - kidney stones - peptic ulcer - nausea - constipation

Question 87

decrease in calcium

Answer 87

hypoparathyroidism

Question 88

causes of hypoparathyroidism

Answer 88

- removal of parathyroid glands during thyroid removal surgery

Question 89

can all parathyroid glands be removed

Answer 89

no or the patient will die

Question 90

what does hypoparathyroidism lead to

Answer 90

hypocalcemia

Question 91

in the absence of PTH what is imminent

Answer 91

death

Question 92

symptoms of hypoparathyroidism

Answer 92

- muscular excitability - neuromuscular excitability - muscle cramps - twitches - tingling - pins and needles - irritability - paranoia

Question 93

what is a consequence of vitamin D deficiency

Answer 93

impaired intestinal absorption of calcium

Question 94

what causes rickets

Answer 94

vitamin D deficiency

Question 95

what is rickets

Answer 95

when bone become soft and deformed bowing under the pressure of weight bearing

Question 96

who usually gets rickets

Answer 96

children

Question 97

what is the condition of vitamin D deficiency in adults

Answer 97

osteomalacia