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Anatomy + Physiology (606) > Endocrine System > Flashcards

Endocrine System Flashcards

1
Q

functions

A

regulates long term processes:
growth, development + reproduction

consists of hormones (chemical messengers) + glands

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2
Q

organs of ES

A

hypothalamus
pineal gland
pituitary gland
parthyroid glands
thyroid gland
adrenal gland
pancreatic islets

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3
Q

endocrine communication

A

through the bloodstream, using hormones, target cells are primarily in other tissues and organs + must have appropriate receptors

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4
Q

endocrine glands

A

ductless glands comprised of endocrine cells
have good blood supply
secrete hormones directly into the bloodstream

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5
Q

hormones

A

organic chemical messengers produced and secreted by endocrine cells into the bloodstream
bind to receptors (binding sites) in target cells (cells with receptors)
stimulates gene expression/ protein synthesis to regulate, integrate and control a wide range of physiological functions

if there is no binding site that is correct/ complementary then there will be no response from that cell/ organ

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6
Q

types of hormones

A

amino acid derivatives- small molecules, structurally similar to amino acids (water soluble)
peptide hormones- chains of amino acids- largest class of hormones (water soluble)
lipid derivatives- 2 classes of lipid based hormones- streoid and eicosanoids (lipid soluble)

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7
Q

steroid hormones

A

anabolic steroids have receptors in muscle that stimulate muscle protein production
not all steroid hormones build muscle
hormones have specific effects
risks of anabolic steroids:
teenagers- early skeletal and sexual maturation (stunted growth)
damage to liver + cardiovascular systems
males- reduced sperm count
females- facial hair

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8
Q

hormone receptor locations

A

on cell membrane- includes receptors for non-lipid soluble hormones inc epinephrine + norepinephrine, adrenaline, peptide hromones and eicosanoids
trigger signalling cascaded inside cell involving: G proteins + second messengers

inside cell- includes receptor for all steroid hormones and thyroid hormones

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9
Q

active of cAMP

extracellular

A
  1. activation of G protein activates enzyme adenylate cyclase
  2. adenylate cyclase converts ATP to cAMP
  3. cAMP activates kinase enzymes
  4. activated kinases affect target cell
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10
Q

different efffects

A

same hormone can have different effects in different cells with different receptors
same hormone can activate different reponses in different target cells
eg adrenaline- binding to B receptors increases cAMP
adrenaline binding to a recpetors stimulates cAMP breakdown

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11
Q

intracellular recptors

A

steroid hormones
1. diffusion through membrane lipids
2. bind to cytoplasmic or nuclear receptors
3. binding of hormone receptor complex to DNA
4. gene activation
5. trancription and mRNA production
6. translation and protein synthesis
alteration of cellular structure or activtity > target cell response

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12
Q

thyroid hormones

A

bind to receptors in mitochondria + in nucleus, increasing ATP production
1. transport across cell membrane
2. binding to receptors at mitochondria and nucleus
same as steroid hormones 3-6

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13
Q

after secretion

A

free hormones- remain functional for less than 1 hour, bind to target cell receptors or broken down in liver, kidney or by enzymes in plasma

thyroid and steroid hormones- remain in circulation much longer as most are bound, emeter bloodstream
more than 99% become attached to special transport proteins, bloodstrema contains substantial reserves of bound hormones

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14
Q

regulation of endocrine system

A

controlled by hypothalamus + negative feedback
hypothalamus- interface between nervous and endocrine systems
regulatory hormones affect pituitary function

pituitary- anterior pituitary - hormones that control other endocrine organs
posterior pituitary- oxytocin and ADH release

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15
Q

hypothalamus activity

A
  1. production of ADH and oxytocin
  2. secretion of regulatory hormones to control activity of the anterior lobe of pituitary gland
  3. control of sympathetic output to adrenal medullae
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16
Q

hypophyseal portal system

A

neurosecretory neurons at median eminence secrete regulatory factors
enter fenestrated capillaries in capillary bed in hypothalamus
into portal veins
into capillary beds in anterior pituitary

17
Q

feedback control of endocrine secretion

A

prolactin regulation- hypothlamus produces releasing factor (PRF) and inhibiting hormone (PIH)

growth hormone regulation- hypothalamus produces releasing hormone (GH-RH) and inhibiting hormone (GH-IH)

18
Q

anterior pituitary hormone

A

effects of growth hormone
acts on liver to promote release of somatomedins eg insulin growth factors (IGFs)
IGFs stimulate tissue gorwth and increase amino acid uptake/ protein synthesis
growth hormone acts directly on tissues to:
stimulate cell division in epithelial and connective tissue
stimulate triglyceride breakdown in adipocytes
stimulate liver glycogen breakdown

19
Q

posterior pituitary hormones

A

ADH- in kidneys, water reabsoprtion - elevation of blood volume and pressure
OXT- males - smooth muscles in ductus deferens and prostate gland
females- uterine smooth muslce (labour contractions) and mamary glands (lactation)

20
Q

pineal gland

A

contains
neurons - collaterals from visual pathways
pinealocytes secrete melatonin- lowest production during daylight
functions of melatonin- influences circadian rhythms + antioxidant

21
Q

thyroid gland

A

anterior to thyroid cartilage of larynx
two lobes connected by narrow isthmus
stores and secretes thyroid hormones- thyroxine + triiodothyronine
thyroid hormones increase sodium pottassium ATPase production

22
Q

effects of thyroid hormones

A

increase oxygen and energy consumption
increase HR
increase sensitivity to sympathetic stimulation
stimulates red blood cell formation
affects activity of other endocrine tissues
increases bone turnover

23
Q

thyroid follicles

A

hollow spheres lined by cuboidal epithelium, surrounded by capillaries
contain colloid (protein rich fluid)
follicle cells synthesise tyrosine rich thryoglobulin
iodine incorporated to form thyroxine and triiodothryonine

24
Q

C cells

A

produce calcitonin
important in calcium homeostasis
reduces serum calcium- deposition in bone, increased excretion by kidney

25
Q

role of calcitonin - calcium

A

involved in regulation calcium ion concentrations
1. rising levels of calcium levels in blood
2. thyroid produces calcitonin
3. increased exretion of calcium by kidneys + calcium deposited in bone
4. blood calcium levels decline - homeostasis restored

26
Q

role of PTH- calcium

A

involved in regulating calcium ions concentrations (when they fall)
1. falling calcium levels in blood
2. parathyroid glands secrete parathyroid hormone (PTH)
3.increased reabsorption of calcium by kidneys, calcium release from bone, increased calcitriol production causes Ca2+ absorption by digestive system
4. blood calcium levels increase- homeostais restored

27
Q

parathyroid glands

A

small glands on posterior of thyroid
parathyroid (chief) cells produce parathyroid hormone (PTH)
PTH is released to increase serum calcium when levels decline

28
Q

adrenal gland

A

two glands superior to each kidney
cortex contains steroid hormones eg glucocorticoids
medulla contains catecholamines- fight or flight, increased blood glucose and heart rate

29
Q

adrenal gland structure

A

top down
zona rectularis- androgens (steroid hormones) have anabolic effects
zona fasciculata- glucocorticoids eg cortisol promote glucose synthesis, fat and protein catabolism, anti inflammatory effects
zona glomerulosa- mineralcorticoids eg aldosterone affect electrolyte compositon

30
Q

pancreatic islet and acini

A

pancreatoc acini (exocrine cells) secrete into digestive tract

pancreatic islet- islet of Langerhans
alpha cells- produce glucagon > increases blood glucose
beta cells- produce insulin > lowers blood glucose

31
Q

role of insulin

A

blood glucose regulation
1. rising blood glucose levels
2. beta cells secrete insulin
3. increases rate of glucose transport into target cells, increased rate of gluocse utilisation + atp generatoon, increased conversion of glucose to glycogen, increased amino acid absorption + protein synthesis, increase triglyceride synthesis
4. blood glucose levels decrease- homeostasos restored

32
Q

role of glucagon

A

blood glucose regulation
1. falling blood glucose levels
2. alpha cells secrete glucagon
3. increased breakdown of glycogen to glucose + fat to fatty acids, increased synthesis and release of glucose
4. blood glucose levels increase- homeostasis restored

33
Q

diabetes mellitis

A

abnormally high blood glucose- hyperglycaemia
if untreated can result in kidney damage, retinal damage, peripheral nerve damage, increase CV disease risk

type 1- often diagnosed in childhood, pancreatic insulin production is inadequate, insulin injection required
insulin dependent

type 2- most common + diagnosed in middle/ older age, reduced tissue response to insulin, managed with diet and exercise
non-insulin dependent

34
Q

patterns of hormonal interaction

A

antagonistic (opposing) effects- eg PTH and calcitonin
synergistic (additive) effects eg GH and glucocorticoids
permissive effects- one hormone is necessary for another to produce effect
integrative effects- hormones produce different but complementary results

35
Q

hormones and growth

A

hormones needed for growth
growth hormones- protein synthesis and cellular growth
thyroid hormones- nervous system development
insulin- supply of energy and nutrients
parathyroid hormone and calcitriol- calcium absorption and deposition in bones
reproductive hormones- cell growth and differentiation/ secondary sexual characteristics

36
Q

alarm phase- fight or flight

A
  1. mobilisation of glucose reserves
  2. changes in circulation
  3. increases in heart and respiratory rates
  4. increased energy use by all cells
37
Q

resistance phase

A

long term metabolic adjustments
1. mobilisation of remaining energy reserves- lipids are released by adipose tissue, amino acids released by skeletal muscle (growth hormone and glucocorticoids)
2. conservation of glucose- peripheral tissue breaks down lipids to obtain energy
3. elevation of blood gluocse concentration- liver synthesises glucose from other carbs, amino acid and lipids (glucagon)
4. conservation of salts and water, loss of K+ and H+ (mineralocorticoids)

38
Q

exhaustion phase

A

collapse of vital systems
causes include
exhaustion of lipid reserves
inability to produce glucocorticoids
failure of electrolyte balance
cumulative structural or functional damage to vital organs

Anatomy + Physiology (606) (15 decks)

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