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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
Q

Pituitary Gland Pathologies

A
  • Agromegaly
  • Gigantism
  • Pituitary tumour
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26
Q

Gigantism and Acromegaly - signs and symptoms

A
  • Large, prominent facial features
  • Large hands and feet
  • Deep voice, impotence
  • Tiredness
  • Joint pains
  • Bone defomities
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27
Q

Gigantism

A
  • Excess growth hormone while bones still developing
  • Growth to massive height
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28
Q

Acromegaly

A
  • Excess growth hormone post-puberty
  • Growth outwards rather than upwards
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29
Q

Gigantism/Acromegaly - complications

A
  • Hypertension, cardiomegaly
  • Type II Diabetes (GH - ⇡ blood glucose - insulin resistance)
  • Osteoarthritis, vertebral collapse
  • Bowel polyps
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30
Q

Hyperprolactinaemia

A
  • Excess prolactin production
  • Cause - pituitary tumour
  • Signs/symptoms
    • Galactorrhoea (milk not associated with childbirth)
    • Amenorrhoea
    • Decreased libido/sexual dysfunction
    • Subfertility
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31
Q

Diabetes Insipidus

A
  • 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)
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32
Q

What does Pineal Gland produce?

A

Melatonin

Sets circadian rhythm

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33
Q

Function of thymus gland

A
  • Thymus hormones promote maturation of T-lymphocytes
  • Thymus atrophies after puberty
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34
Q

Thyroid Gland - function

A
  • Metabolic rate
  • Important ‘growth hormone’ early in life
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35
Q

What do ‘follicular cells’ in thyroid produce?

A
  • Thyroxine (T4) - 4 iodine atoms
  • Triiodothyronine (T3) - 3 idoine atoms

Follicular cells ‘trap’ and store most of body’s iodide

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36
Q

Parafollicular cells - function

A

Secrete hormone ‘calcitonin’ - lowers blood calcium levels

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37
Q

What is major thyroid hormone in blood

A

Thyroxine (T4)

T3 more biologically active - ¾ times more potent than T4

Selenium and zinc used to convert from T4 to T3

38
Q

What do thyroid hormones do?

A
  • 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
Q

Hyperthyroidism

A
  • Underactive thryoid
40
Q

Hypothryroidism - Symptoms

A
  • Tiredness
  • Malaise
  • Weight gain
  • Constipation
  • Depression
  • Cold intolerance
  • Slow cognition, poor memory, menstrual changes
41
Q

Hypothyroidism - signs

A
  • Goitre
  • Dry, brittle skin, thin hair, loss of eyebrows
  • Myxoedema (swelling) around eyes
  • slow tendon reflexes
  • Bradycardia
  • High TSH, low thyroid hormones
42
Q

Hypothyroidism - causes

A
  • Hashimoto’s thyroidism (autoimmune)
  • Iodine deficiency
  • Thyroid destruction - radioactive iodine, surgery, medications
43
Q

Hyperthyroidism (Graves’ Disease)

A
  • Hyper-metabolism
  • More common in women (10:1)
44
Q

Hyperthyroidism (Graves’ Disease) - Causes

A
  • Autoimmune - increased IgG antibodies bind to TSH receptor and stimulate production of thryoid hormones
  • Excessive iodine supplementation
  • Tumour
45
Q

Hyperthyroidism (Graves’ Disease) - Signs and Symptoms

A
  • 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
Q

What is Barnes Temperature Test

A
  • 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
Q

What is calcitonin

A
  • 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
Q

Parathyroid Hormone - function

A
  • Increases blood calcium by:
    • ⇑ osteoclast activity
    • ⇑ kidney reabsorption of calcium
    • ⇑ production calcitriol (increases calcium absorption in GIT)
49
Q

Hyperparathyroidism

A
  • Elevated levels of parathryroid hormone, improper calcium regulation
  • Often no signs/symptoms
  • Hypercalcaemia - increased risk of kidney stones, osteoporosis
50
Q

Hypoparathyroidism

A
  • 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
Q

2 types of adrenal glands

A
  • 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
Q

What is function of adrenaline and noradrenaline?

A
  • 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
Q

Glucocorticoids

A
  • Steroid hormones produced in adrenal cortex
  • Regulate metabolism and resistance to stress
54
Q

Glucocorticoids - activities

A
  • Stimulate gluconeogenesis (new glucose)
  • Proteolysis (amino acids from proteins)
  • Lipoysis
  • Glucose production by liver
  • Reduce immune response
  • Anti-inflammatory
55
Q

Mineralocorticoids

A
  • Primarily aldosterone
  • Maintains water and electrolyte balance
56
Q

Sex Hormones

A
  • Primarily adrogens in the form of DHEA
  • Production of public and axillary hair
  • Growth - increase muscle mass
  • Stimulated by CRH ⇥ ACTH
57
Q

Cushing Syndrome

A
  • Cortisol excess
  • Cause - corticosteroid therapy, adrenal adenoma, pituitary adenoma
58
Q

Cushing’s Disease

A
  • Excess production ACTH
  • Pituitary tumour
59
Q

Cushing’s Syndrome/Disease - Signs and Symptoms

A
  • Central weight gain, moon face, buffalo hump, insulin resistance
  • Depression, insomnia, psychosis, hirsutism
  • Easy bruising, thin skin
  • Reduced immunity
  • Bone fractures, osteoporosis
60
Q

Addison’s Disease

A
  • 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
Q

Addisons’s Disease - pathophysiology

A
  • 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
Q

Addisonian Crisis

A
  • Inability to cope with stress (psychological, infection)
  • Severe lethargy, low bP
  • Hypoglycaemic, fainting
  • Severe pain, renal failure
63
Q

What is the organ associated with the endocrine function of the pancreas?

A

Islets lf Langerhans

64
Q

3 endocrine cells of pancreas

A
  1. Alpha - produce glucagon
  2. Beta - produce insulin
  3. Delta - produce somatostatin (GHIH)
65
Q

What is the main endocrine function of the pancreas?

A

Regulate blood glucose levels

66
Q

Insulin - function

A
  • 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
Q

How is insulin stimulated (directly and indirectly)

A
  • Directly
    • High blood glucose and blood amino acids
    • Eating, sweet taste
  • Indirectly
    • GH and ACTH - elevate blood sugar levels
68
Q

How is insulin reduced

A
  • Low blood glucose
  • Starvation
  • Gluagon
69
Q

What is the function of glucagon and where is it found?

A
  • Liver
  • Elevates blood glucose
  • Opposite of insulin
  • Liver converts glucagon to glucose (glycogenolysis)
70
Q

What is diabetes mellitus?

A
  • Metabolic disorder associated with hyperglycaemia
  • Deficiency of insulin
  • Due to impaired production or insulin resistance
71
Q

Types of diabetes mellitus

A
  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
Q

Type I Diabetes - definition

A
  • Absolute deficiency of insulin
  • Permanent hyperglycaemia
73
Q

Type I Diabetes - causes

A
  • Autoimmune - destruction pancreatic beta cells
  • Genetic susceptibility
  • Viruses (eg polio)
  • Diet (infant exposure to dairy, Vit D deficiency, early exposure to gluten)
74
Q

Type I Diabetes - Signs and Symptoms

A
  • 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
Q

Type I Diabetes - Allopathic treatment

A

Insulin

76
Q

Type II Diabetes - Definition

A
  • Cells develop insulin resistance ⇒ glucose cannot enter cells
  • Hyperglycaemia develops - pancreatic beta cells no longer secrete insulin to compensate for insulin resistance
77
Q

Type II Diabetes - Causes

A
  • 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
Q

Type II Diabetes

A
  • Polydipsia
  • Polyuria
  • Polyphagia
  • Acanthosis nigricans (skin goes a bit dark, dirty looking)
  • Often asymptomatic, mild hyperglycaemia
79
Q

Type II Diabetes - Diagnosis

A
  • Fasting/random blood glucose test
  • Oral glucose tolerance test
  • Glycated haemoglobin
  • Urine test (assists diagnosis)
80
Q

Diabetic complications

A
  • Heart disease, hypercholesterolaemia,l hypertension
  • Retinopathy (damage tiny blood cells in eyes)
  • Nephropathy (diabetic kidney disease)
  • Peripheral neuropathy
81
Q

Ketoacidosis

A
  • 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
Q

Hypoglycaemiaa

A

Can affect diabetics in response to insulin

83
Q

Hypoglycaemia - signs/symptoms

A
  • Shaking and trembling
  • Sweating
  • Pins and needles in lips and tongue
  • Extreme hunger and irritability (‘hangry’)
  • Headache
  • Slurred speech, confusion, tiredness
84
Q

Local hormones

A
  • Histamine
  • Prostaglandins
  • Serotonin
  • Dopamine
  • Erthropoietin
  • CCK

produced by tissues that act on cells in local aarea

85
Q

Histamines

A
  • Secreted by - Basophils, mast cells
  • Action - Inflammation, vasodilation, increased blood vessel permeability
86
Q

Prostaglandins

A
  • Secreted by: most tissues
  • Chemical messengers
  • Many processes
  • Regulate inflammation, thickness of blood
87
Q

Serotonin

A
  • Secreted by - intestines, brain
  • Blood clotting, temperature regulation, appetite, sleep
88
Q

Dopamine

A
  • Secreted by - brain mostly
  • Muscle tone and some movements
89
Q

Erythropoietin

A
  • Secreted by - kidneys
  • Red blood cell production
90
Q

CCK

A
  • Secreted by: GIT
  • Stimules bile and pancreatic juice secretion

Biomed 1 - Revision Deck (9 decks)

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