Loss Of Homeostasis Flashcards

1
Q

What are the 2 growth hormone diseases

A

Excess growth hormone - gigantism
Deficient growth hormone levels - primordial dwarfism

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2
Q

What causes gigantism

A

A tumour in the anterior pituitary. Unregulated growth results in unregulated growth hormone secretion

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3
Q

What is infantile hypothyroidism causes and symptoms

A

Causes: lack of iodine in mothers diet during gestation, breast feeding
Symptoms: Low metabolic rate, cold intolerant, retarded growth, brain development inhibited

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4
Q

Outline simple goitre/iodine deficiency disorder

A

Iodine deficiency, thyroid gland unable to make TH. When TH depleted, TRH and TSH secretion increases to stimulate thyroid gland production of TH. Without iodine, TH cannot be made
Loss of negative feedback control, and overstimulation of thyroid gland
Excess TSH stimulates growth of thyroid gland

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5
Q

What is Graves’ disease, its causes and symptoms

A

Too much thyroid hormone. Antibodies bind receptors, triggering over production of thyroid hormone
Causes: autoimmune disorder
Symptoms: High metabolic rate. Weight loss

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6
Q

What is Hyperparathyroidism

A

Too much parathyroid hormone
Leads to excess PTH, usually causes by a parathyroid tumour.
Bones become soft, reformed, fragile - too much calcium removed from bone
Raises calcium and phosphate blood concentrations
Promotes formation of calcium phosphate kidney stones (high mineral concentrate during crystallises)

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7
Q

What is Hypercalcaemia

A

Too much blood calcium
Nerve and muscle cells less responsive and excitable
Can lead to depression of the nervous system, emotional disturbance, muscle weakness, sluggish reflexes
If plasma levels are significantly elevated, can lead to cardiac arrest

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8
Q

What are the causes and symptoms of hypocalcemia

A

Caused by: vitamin D deficiency, diarrhoea, thyroid tumours (unregulated C cells producing calcitonin - reduces blood Ca2+ levels), under reactive or removed parathyroid glands, Pregnancy and lactation
Symptoms: increased excitability of the nervous system, muscle tremors, spasms, cramps,

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9
Q

What happens when blood Ca2+ levels get very low

A

Paraesthesia - tingling/burning sensation in hands and face
Muscle cramps,
Muscle of larynx contract tightly - suffocation

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10
Q

Outline the hypercalcemic effects on resting membrane potential and thus neural activation

A

Hypercalcemia = high extracellular Ca2++ levels
+20mV outside cell
Resting membrane potential -90mV (opposed to 70mV)
Much greater potential required to reach threshold for action potential generation

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11
Q

Outline the hypocalcemic effect on the resting membrane potential of a cell and thus neural activation

A

Hypocalcemia = low extracellular Ca2+ levels
Resting membrane potential = -60mV (opposed to -70mV)
Much smaller local potential required to reach threshold and thus to give rise to action potentials

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12
Q

Outline type 1 diabetes mellitus

A

Hyposecretion - minimal/no insulin secretion
Cause: Can be caused by autoimmune distraction of beta cells
Symptoms: glucosuria (glucose in urine), polyuria (excess urine volume)
Treatments: insulin injections or infusions

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13
Q

Why can’t insulin be oral taken e.g in a tablet

A

Insulin is a peptide hormone, hence digestive system would break down into constitutive components (amino acids)

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14
Q

Outline type 2 diabetes mellitus

A

Hyposensitive receptors - too little/no responce to insulin “insulin resistance”
Cause: desensitisation of insulin receptor - associated with obesity
Symptoms: Glycosuria (glucose in urine), polyuria (excess urine)
Treatment: Changes in diet and exercise, various medications

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15
Q

What is primary action of glucagon, and what else carries out this function

A

Primary action is increase blood glucose
Growth hormone, Adrenaline

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16
Q

When might you need to change set point of homeostatic system

A

Change in altitude (less O2, require more oxygen carrying molecules in blood