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Biomed 1 - Revision Deck > Lecture 9 - Endocrine System > Flashcards

Lecture 9 - Endocrine System Flashcards

1
Q

Hormones

A
  • Chemical messengers released into the blood from glands which produce them
  • Have specific target cells
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2
Q

3 types of hormones

A
  1. Peptides - proteins (water soluble), i.e. insulin
  2. Steroids - sex hormones, e.g. oestrogen
  3. Amino acid derivatives - adrenaline, thryroxine
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3
Q

Autonomic nervous system vs endocrine system

A
  1. Autonomic nervous system
    1. Rapid change
    2. less precise
    3. Shorter duration
    4. Neurotransmitters
    5. Control Centre - central nervous system
  2. Endocrine system
    1. Slower change
    2. More precise
    3. Longer duration
    4. Hormones
    5. Control Centre - hypothalamus
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4
Q

2 types of glandes

A
  1. Exocrine - excrete products into ducts
  2. Endocrine - excrete directly into blood
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5
Q

Examples - exocrine glands

A
  • Salivary
  • Gastric (digestive enzumes)
  • Mammary glands
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6
Q

Examples - endocrine glans

A
  • Pituitary
  • Adrenals
  • Thyroid
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7
Q

Glands

A
  • Hypothalamus (brain)
  • Pituitary (brain)
  • PIneal (brain)
  • Thyroid (neck)
  • Parathyroid - back of neck
  • Adrenal - above kidneys
  • Pancreatic: islets of Langerhans
  • Thymus - behind breastbone
  • Ovaries
  • Testes
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8
Q

Endocrine Tissues

A

Tissues not considered glands but with endocrine function (produce hormones)

  • Adipose - fat
  • Heart - blood pressure
  • GIT - stomach - ghrelin and gastrin (satiety and gastric emptying)
  • Liver - insulin-like growth factor (IGF), thrombopoetin
  • Placenta - human chorionic gonadotropin (hCG)
  • Kidneys - erythropoietin (RBC production)
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9
Q

Hormone Regulation

A
  1. Down-regulation
    1. Excess hormone - ⇣ number of target cell receptors
    2. Example - puberty
  2. Up-regulation
    1. Hormone deficiency - ⇡ number of target cells receptors
    2. Example - ⇡ Oxytocin receptors during 3rd trimester pregnancy
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10
Q

What is the ‘master endocrine gland’?

A

Pituitary gland

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11
Q

Pituitary

A
  • Signalled by hypothalamus
  • Anterior and posterior
  • Major link between nervous and endocrine system
  • Together control - growth, metabolism, development, homeostasis
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12
Q

Hypothalamus - Releasing Hormones

A
  • TRH - Thyroid Releasing Hormone
  • GHRH - Growth Hormone Releasing Hormone
  • CRH - Corticotropin Releasing Hormone
  • PRH - Prolactin Releasing Hormone
  • GnRH - Gonadotropin Releasing Hormone
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13
Q

Hypothalamus - Inhibiting Hormones

A
  • GHIH - Growth Hormone Inhibiting Hormone
  • PIH - Prolactin Inhibiting Hormone
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14
Q

Anterior Pituitary Hormones

A
  • TRH - TSH - thyroid gland
  • GHRH/GHIH - GH - Most body tissues
  • CRH - ACTH & MSH - Adrenal Cortex and skin
  • PRH/PIH - Prolactin - breasts
  • GnRH - FSH (Follicle Stimulating Hormone) and LH (Leutenizing Hormone) - ovaries and testes
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15
Q

Posterior Pituitary Hormones

A
  • Oxytocin
  • Antidiuretic hormone - ADH
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16
Q

Growth Hormone (GH)

A
  • Regulates metabolism
  • Stimulates release of insulin-like growth factors (IGF) in cells
  • Promotes growtn and cell devision
  • Breaks down fats and glycogen
  • Increased production at night
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17
Q

Thyroid Stimulating Hormone (TSH)

A
  • Production of thyroid hormones T4 and T5
  • Lowest in early evening, highest at night
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18
Q

Adrenocorticotropic Hormone (ACTH)

A
  • Output steroid hormones, especially cortisol
  • Circadian rhythm (sleep/wake cycle)
  • Increased production - hypoglycaemia, exercise, stress
  • Highest in morning, lowest at midnight
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19
Q

Prolactin

A
  • Stimulates lactation
  • Prevents pregnancy during lactation
  • Breast maturation after childbirth
  • Production - after birth, suckling, emotional stress, sleep
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20
Q

Follicle Stimulating Hormone (FSH)

A
  • Production gametes (sex cells) in males and females
  • Increases oestrogen production (F) - eggs
  • Stimulates testosterone production (M) - sperm
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21
Q

Luteinising Hormone (LH)

A
  • Triggers ovulation
  • Increases progesterone (F)
  • Stimulates testosterone (M)
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22
Q

Melanocyte Stimulating Hormone (MSH)

A
  • Produced in response to UV light
  • Stimulated by ‘corticotropin releasing hormone’ CRH - released from hypothalamus
  • Skin, hair, eye pigmentation
  • Excessive production - Addison’s disease
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23
Q

Oxytocin

A
  • Posterior pituitary
  • Contracts uterus during childbirth
  • Contracts lactating breast
  • Bonding hormone
  • Produced by: suckling, childbirth (positive feedback), emotional state
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24
Q

Antidiuretic Hormone

A
  • Posterior pituitary
  • Reduces urine output - stimulates reabsorption of water in the kidneys
  • Vasoconstriction in skin and abdominal organs to ⇑ blood pressure
  • Production - ⇑ osmotic pressure, hypovolaemia (reduced fluid intake, vomiting, thirst)
  • Inhibition - ⇓ osmotic pressure, alcohol
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25
Pituitary Gland Pathologies
* Agromegaly * Gigantism * Pituitary tumour
26
Gigantism and Acromegaly - signs and symptoms
* Large, prominent facial features * Large hands and feet * Deep voice, impotence * Tiredness * Joint pains * Bone defomities
27
Gigantism
* Excess growth hormone _while bones still developing_ * Growth to massive height
28
Acromegaly
* Excess growth hormone _post-puberty_ * Growth outwards rather than upwards
29
Gigantism/Acromegaly - complications
* Hypertension, cardiomegaly * Type II Diabetes (GH - ⇡ blood glucose - insulin resistance) * Osteoarthritis, vertebral collapse * Bowel polyps
30
Hyperprolactinaemia
* Excess prolactin production * Cause - pituitary tumour * Signs/symptoms * **Galactorrhoea** (milk not associated with childbirth) * **Amenorrhoea** * Decreased libido/sexual dysfunction * Subfertility
31
Diabetes Insipidus
* Deficient ADH production - kidneys over-excrete water * Causes * Cranial - brain trauma, tumour, encephalitis * Renal - chronic kidney disease * Signs/symptoms * Polydipsia - extreme thirst * Polyuria - excess urine * Weight loss * Low BP, fainting (hypovolaemia)
32
What does Pineal Gland produce?
Melatonin Sets circadian rhythm
33
Function of thymus gland
* Thymus hormones promote maturation of T-lymphocytes * Thymus atrophies after puberty
34
Thyroid Gland - function
* Metabolic rate * Important ‘growth hormone’ early in life
35
What do ‘follicular cells’ in thyroid produce?
* Thyroxine (T4) - 4 iodine atoms * Triiodothyronine (T3) - 3 idoine atoms Follicular cells ‘trap’ and store most of body's iodide
36
Parafollicular cells - function
Secrete hormone ‘calcitonin’ - lowers blood calcium levels
37
What is major thyroid hormone in blood
Thyroxine (T4) T3 more biologically active - ¾ times more potent than T4 Selenium and zinc used to convert from T4 to T3
38
What do thyroid hormones do?
* Increase metabolic rate and heat production * Essential for growth and CNS function * Work in conjunction with adrenaline and noradrenaline, insulin and growth hormone * Stimulated by: TSH, exercise, stress, malnutrition * Highest levels at night * Higher levels during adolescence, pregnancy, female reproductive years
39
Hyperthyroidism
* Underactive thryoid
40
Hypothryroidism - Symptoms
* Tiredness * Malaise * Weight gain * Constipation * Depression * Cold intolerance * Slow cognition, poor memory, menstrual changes
41
Hypothyroidism - signs
* Goitre * Dry, brittle skin, thin hair, loss of eyebrows * Myxoedema (swelling) around eyes * slow tendon reflexes * Bradycardia * High TSH, low thyroid hormones
42
Hypothyroidism - causes
* Hashimoto's thyroidism (autoimmune) * Iodine deficiency * Thyroid destruction - radioactive iodine, surgery, medications
43
Hyperthyroidism (Graves' Disease)
* Hyper-metabolism * More common in women (10:1)
44
Hyperthyroidism (Graves' Disease) - Causes
* Autoimmune - increased IgG antibodies bind to TSH receptor and stimulate production of thryoid hormones * Excessive iodine supplementation * Tumour
45
Hyperthyroidism (Graves' Disease) - Signs and Symptoms
* Nervousness, irritability, hyperactivity, unexplained weight loss * Insomnia, palpitations, muscle weakness, frequent bowel and bladder movement, diarrhoea, fatigue * Heat sensitivity, sweating * Signs - goitre, exopthalmos (bug eye), tachycardia, tremor
46
What is Barnes Temperature Test
* Measure core body temperature * On waking, before getting out of bed with as little movement as possible * Leave in position 10 minutes * Test for 5 consecutive days * Make note of 3 lowest readings * Below 36.3° - may indicate hypothyroidism * Above 37 - may indiate hyperthryoidism
47
What is calcitonin
* Produced by parafollicular cells of thyroid gland * Important during childhood for bone growth * Lowers blood calcium by: * Inhibiting calcium reabsorption from bone and kidneys * Inhibiting osteoclast activity
48
Parathyroid Hormone - function
* Increases blood calcium by: * ⇑ osteoclast activity * ⇑ kidney reabsorption of calcium * ⇑ production calcitriol (increases calcium absorption in GIT)
49
Hyperparathyroidism
* Elevated levels of parathryroid hormone, improper calcium regulation * Often no signs/symptoms * Hypercalcaemia - increased risk of kidney stones, osteoporosis
50
Hypoparathyroidism
* Hypo-metabolism, reduced parathyroid hormone (PTH) * Cause - usually radiation or surgery * Signs - hypocalcaimia - muscle cramps and spasms, tingly lips, dry haair, brittle nails, dry scaly skin
51
2 types of adrenal glands
* **Medulla** (inner) * Part of autonomic nervous system * Produces - adrenaline, noradrenaline, dopamine * **Cortex** (outer) * Produces 3 types of steroid hormones * Corisol * Aldosterone * Sex hormones (mostly androgens)
52
What is function of adrenaline and noradrenaline?
* Intensity sympathetic response * Released by chromaffin cells (quick release) * Adrenaline - heart * Noradrenaline - blood vessels * Stimulated by: exercise, fasting, shock, infection, disease, stress, caffeine * Inhibited by: eating, sleeping, calmness
53
Glucocorticoids
* Steroid hormones produced in adrenal cortex * Regulate metabolism and resistance to stress
54
Glucocorticoids - activities
* Stimulate gluconeogenesis (new glucose) * Proteolysis (amino acids from proteins) * Lipoysis * Glucose production by liver * Reduce immune response * Anti-inflammatory
55
Mineralocorticoids
* Primarily aldosterone * Maintains water and electrolyte balance
56
Sex Hormones
* Primarily adrogens in the form of DHEA * Production of public and axillary hair * Growth - increase muscle mass * Stimulated by CRH ⇥ ACTH
57
Cushing Syndrome
* Cortisol excess * Cause - corticosteroid therapy, adrenal adenoma, pituitary adenoma
58
Cushing's Disease
* Excess production ACTH * Pituitary tumour
59
Cushing's Syndrome/Disease - Signs and Symptoms
* Central weight gain, moon face, buffalo hump, insulin resistance * Depression, insomnia, psychosis, hirsutism * Easy bruising, thin skin * Reduced immunity * Bone fractures, osteoporosis
60
Addison's Disease
* Adrenal insufficiency * Causing deficiency of mineralocoritoids and glucocorticoids * Causes - atrophy of adrenal gland (often AI) 85% * Signs/Symptoms * weakness, fatigue, hypotension * Hyperpigmentation of skin and mucous membranes * Diarrhoea, weight loss, malaise, muscle weakness, increased thirst
61
Addisons's Disease - pathophysiology
* Failure of normal negative feedback mechanism * adrenal failure ⇒ lack of adrenal hormone production * Hypothalamus produces excess corticotrophin releasing hormone (CRH) * ⇒ pituitary produces excess melanocyte stimulating hormone * ⇒ hyperpigmentation
62
Addisonian Crisis
* Inability to cope with stress (psychological, infection) * Severe lethargy, low bP * Hypoglycaemic, fainting * Severe pain, renal failure
63
What is the organ associated with the endocrine function of the pancreas?
Islets lf Langerhans
64
3 endocrine cells of pancreas
1. **Alpha** - produce _glucagon_ 2. **Beta** - produce _insulin_ 3. **Delta** - produce _somatostatin_ (GHIH)
65
What is the _main endocrine function_ of the pancreas?
Regulate blood glucose levels
66
Insulin - function
* Lower blood glucose levels, amino acids and fatty acids * Stimulates cells to uptake glucose from blood * Promote synthesis of * proteins (growth & repair) * glucogen - glycogenesis (stored form of carbohydrate) * fats - lipogenesis (stored for energy)
67
How is insulin stimulated (directly and indirectly)
* Directly * High blood glucose and blood amino acids * Eating, sweet taste * Indirectly * GH and ACTH - elevate blood sugar levels
68
How is insulin reduced
* Low blood glucose * Starvation * Gluagon
69
What is the function of **glucagon** and where is it found?
* Liver * Elevates blood glucose * Opposite of insulin * Liver converts glucagon to glucose (glycogenolysis)
70
What is diabetes mellitus?
* Metabolic disorder associated with hyperglycaemia * Deficiency of insulin * Due to impaired production or insulin resistance
71
Types of diabetes mellitus
1. Type I - autoimmune 2. Type II - Insulin resistance 3. Secondary (1-2% of cases) - i.e as a result of pancreatisis 4. Gestational - as a result of placental hormones
72
Type I Diabetes - definition
* Absolute deficiency of insulin * Permanent hyperglycaemia
73
Type I Diabetes - causes
* Autoimmune - destruction pancreatic beta cells * Genetic susceptibility * Viruses (eg polio) * Diet (infant exposure to dairy, Vit D deficiency, early exposure to gluten)
74
Type I Diabetes - Signs and Symptoms
* Polydipsia (excessive thirst) * Polyuria * Polyphagia (excessive appetite) * Glycosuria (glucose in urine) * Unexplained weight loss * Weakness, extreme fatigue * Blurred vision * Slow healing of cuts/infections
75
Type I Diabetes - Allopathic treatment
Insulin
76
Type II Diabetes - Definition
* Cells develop insulin resistance ⇒ glucose cannot enter cells * Hyperglycaemia develops - pancreatic beta cells no longer secrete insulin to compensate for insulin resistance
77
Type II Diabetes - Causes
* Genetic (Native Americans, Hispanics, African-Americans, Asians) * Lifestyle - obesity, weight gain, low fibre, high GI (glycaemic) diet (sugar, white rice, white bread), lack of exercise
78
Type II Diabetes
* Polydipsia * Polyuria * Polyphagia * Acanthosis nigricans (skin goes a bit dark, dirty looking) * Often asymptomatic, mild hyperglycaemia
79
Type II Diabetes - Diagnosis
* Fasting/random blood glucose test * Oral glucose tolerance test * Glycated haemoglobin * Urine test (assists diagnosis)
80
Diabetic complications
* Heart disease, hypercholesterolaemia,l hypertension * Retinopathy (damage tiny blood cells in eyes) * Nephropathy (diabetic kidney disease) * Peripheral neuropathy
81
Ketoacidosis
* Glucose supply is low or when cells cannot utilise glucose, the mitochondria uses ketones to make energy * Ketones - from breakdown of fatty acids * Can be toxic in high levels * May result in coma or death * Tested using urine dipstick * Fruity breath, increased thirst
82
Hypoglycaemiaa
Can affect diabetics in response to insulin
83
Hypoglycaemia - signs/symptoms
* Shaking and trembling * Sweating * Pins and needles in lips and tongue * Extreme hunger and irritability ('hangry') * Headache * Slurred speech, confusion, tiredness
84
Local hormones
* Histamine * Prostaglandins * Serotonin * Dopamine * Erthropoietin * CCK produced by tissues that act on cells in local aarea
85
Histamines
* Secreted by - Basophils, mast cells * Action - Inflammation, vasodilation, increased blood vessel permeability
86
Prostaglandins
* Secreted by: most tissues * Chemical messengers * Many processes * Regulate inflammation, thickness of blood
87
Serotonin
* Secreted by - intestines, brain * Blood clotting, temperature regulation, appetite, sleep
88
Dopamine
* Secreted by - brain mostly * Muscle tone and some movements
89
Erythropoietin
* Secreted by - kidneys * Red blood cell production
90
CCK
* Secreted by: GIT * Stimules bile and pancreatic juice secretion

Biomed 1 - Revision Deck (9 decks)

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