Endocrine System Flashcards
1
Q
what is the endocrine system?
A
all the organs and tissues that release hormones
2
Q
what is an endocrine gland
A
system of ductless glands that make hormones
3
Q
why are endocrine glands ductless
A
secretions are released into blood straight away
4
Q
give an example of an organ that secretes hormones
A
pancreas
5
Q
give example of pure endocrine gland
A
Pituitary/Pineal/Thyroid/Parathyroid/Adrenal with 2 glands medulla and cortex
6
Q
give examples of endocrine cells in other organs
A
Pancreas/Thymus/Gonads/Hypothalamus
7
Q
what is the difference between purely endocrine glands and endocrine cells in other organs?
A
pure endocrine just endocrine whereas endocrine cells in other organs mean they serve both endocrine and exocrine
8
Q
what is the difference between endocrine and exocrine
A
endocrines do not have ducts whereas exocrines do, endo just release hormones whereas exocrine release sweat enzymes and mucus
endocrine products released directly into blood stream whereas exocrine are released into an internal organ or external surface through a duct
9
Q
give examples of endocrine
A
thyroid,parathyroid,pituitary/adrenal
10
Q
give examples of exocrine
A
saliva/liver/oesophageal glands
11
Q
describe the 3 elements of endocrine system
A
chemical which mean hormones are sent to messengers/ remote communication system/control a huge no of physiological processes
12
Q
what are the components of the endocrine system
A
endocrine glands and hormones
13
Q
what are endocrine glands
A
ductless glands, comprised of endocrine cells, releasing blood directly into blood stream
14
Q
what are pheromones
A
hormones outside of the body signalling to others of same species
15
Q
what do pheromones relate to in animals
A
alarm/food/sex
16
Q
what are hormones
A
organic chemical messengers made by endocrine cells secreted into blood stream
17
Q
how do hormones work
A
hormones regulate/integrate and control physio functions
18
Q
how do hormones travel in body
A
circulate in blood, theyre long distance messengers, and act on distant target cells
19
Q
whats the difference between autocrine and paracrine
A
autocrine activates same cell, whereas paracrine activates neighbouring cells
20
Q
what is autocrine and paracrine signalling
A
when a cell acts as a self regulator or regulates neighbouring cells
21
Q
what are target cells
A
cells that contain a specific receptor for a particular hormone
22
Q
where are hormone receptors
A
on target cells
23
Q
where can hormone receptors be found
A
surface,cytoplasm,nucleus
24
Q
how are target cells activated
A
when specific hormones bind to them
25
what happens if a hormone cannot bind or does not bind to receptor
no physiological results
26
how do hormones work
activate a specific response in a specific target cell
27
give the stages of the programmed response of target cells
bind to receptor=receptor hormone complex / enters nucleus / acts as a trasncription factor binding to DNA/ activates or represses one or more genes / forms a cell type specific
28
what is a cell type specific
specific phenological/ morphological functions
29
give different actions of hormones
fetal growth/cell growth and cancer/metabolism/cardiovascular function/renal function/skeletal function/reproductive function/immune function/cns function
30
describe the 3 hormone classifictaions
peptide / amino acids derivatives/ steroid hormones
31
what are lipophilic hormones
non polar hormones that are fat soluble that bind to intracellular recptors
32
give examples of lipophilic hormones
steroid and thyroid hormones
33
why can lipohillic hormones bind to intracellular receptors
can pass the lipid bilayer of cells
34
35
what is a hydrophillic hormone
polar watre soluble hormone
36
give examples of hydrophobic hormones
all other hormones that are not steroid or thyroid
37
where do hydrophillic hormones bind to
extra cellular receptors
38
what are peptide hormones
hormones comprimised of amino acids
39
where are peptide hormones synthesized
ribosomes on the rough endoplasmic reiticulum
40
where can peptide hormones be stored
in vesicles
41
why cant peptide hormones readily pass through cell membrances
because theyre water soluble
42
where are peptide hormone receptors found
cell surface of target cells
43
why do peptide hormones bind to receptors on surface target cell
theyre not lipid soluble
44
what are the 3 amino acid derivatives
tyrosine/thyroid hormones/tryptophan
45
give examples of tyrosine derivatives
catecholamines eg epinephrine/norepinephrine/dopamine
46
give examples of thyroid hormones
t4 thyroxine / t3 triidothyronine
47
give examples of trytophan derivatives
melatonin
48
What are steroid hormones produced by?
gonads, adrenal cortex and kidneys
48
what are steroid hormones derived from
cholestrol
49
can steroid hormones be stored in vesicles in the endo system that produce them
no
50
are steroid hormones lipid soluble
yes
51
where are steroid hormones receptors located
inside their target cell
52
what are the two types of steroid hormones
adrenal and sex hormones
53
what is homeostasis
process of keeping inside body steady and balanced
54
what happens to blood vessels when body temp rises
blood vessels open= heat is lost to outised environment, sweat glands seceret fluid = heat lost = body temp decreases= normal body temp
55
what happens when temperature of body falls
blood vessels get smaller = heat is not lost body starts to shiver= produces heat and so temp rises
56
what is the process of fine regulation
constant monitoringof homeostasis and adjustments in neural and endocrine control
57
what is negative feedback
body turns off signal in response to change in body
58
is negative feedback homeostatic or not
its homeostatic
59
what is positive feedback
signal starts another signal
60
give and example of positive feedback
childbirth
61
give an example of negative feedback
regulation of thyroid levels
62
what happens in the negative feedback cycle
level of hormones control its own production/ secretion
63
what are the 3 examples of neurohormones
neurotransmitters/hormones produced by neurons/releasing hormones
64
what are neurotransmitters
neurohormones that are released into blood by chromaffin cells
65
where are chromaffin cells found
medulla of adrenal glands
66
give an example of hormones produced by neurons
oxytocin and vasopressin produced in the hypothalamus, transported to the posterior pituitary
67
give examples of releasing hormones
growth hormone releasing which is produced in the hypothalamus and travels to anterior pituitary
68
what do releasing hromones stimulate
a gland instead of a target organ
69
what are the three mechanisms of hormone release and explain them
humoral- response to changing levels of ions or nutrients in blood
neural -stimulation by nerves
hormonal- stimulation recieved by other hormones
70
what does the endocrine system comprise of
primary and secondary endocrine organs
71
what are hormones
chemical signals that enter blood and act as distant target sites
72
what are the two main regulators of the endocrine system
hypothalamus and endocrine system
73
what is the normal pathway of hormones
hypothalamus- activate pituitary gland= pituitary release hormone = activate end organ
74
what 2 mechanisms control hormone release
+/- feedback
75
where is the pituitary gland located
underneath brain, behind bridge of nose
76
what is another name for pit gland
hypophysis
77
what is the name for the anterior pit gland
adenohypophysis
78
what is the name for the posterior pit gland
neurohypophysis
79
what is the posterior pit gland attached to?
hypothalamus
80
describe the anterior pit gland
true endocrine gland, pit gland composed of 6 distinctive endocrinocytes, under control by the hormones released by hypothalamus, portal veins carry blood from hypothalamus to pituitary
81
what is the hypophyseal portal system
communicates the HYPO AND ANTERIOR PITUITARY, hyp secrete hormones=start/stop secretion of anterior pit
82
where are pepride hromones synthesised
cell body of hypothalamic neuros
83
in neurohypophysis, where are the hormones released
into the hypophyseal vein
84
what hormones does the anterior gland release
tsh/adrenocorticotropic hormone/fsh/lh/prolactin/growth hormone
85
what does the posterior gland release
adh( antidiuretic hormone) and oxytocin
86
what is the role of prolactin
breast development and milk production, found in low levels in Both males and females
87
what is the role of growth hormone
growth and puberty/ levels decrease through life span
88
what is the role of the adrenocorticotrophic hormone
stimulates adrenal glands to release corticosteroids, responding to stress
89
what is the role of thryoid stimulating hromone
stimulates thyroid release, involved in regulating metabolism
90
what is the role of leutinizing hormone
ovulation and stimulates androgen release by testis
91
what is the role of fsh
growth and oestrogen production from ovary and stimulates sperm follicle production
92
what does adh control
water retention and vesse constriction
93
what does oxytocin control
uterine contraction and breast feeding
94
what does the hypo secrete
releasing hormone- stimulate the making and releasing of 1 or more hormones in ant pit gland
inhib hormone- prevent synth and release of hormones by ant pit gland
95
where does the hyp recieve input from
cortex/thalamus/limbic system
96
what does dopamine inhibit
prolactin
97
what would happen if the pit glands fail
diabetes=too little ADH
Acromegaly=too much GH in Adulthood
Gigantism= too much GH in childhood
98
what are the causes and symptoms of gigantism and acromegaly
too much GH made=bigger thicker broader bones= anterior pit tumours
99
where is the thyroid gland located and what is its role
anterior neck trachea,two lobes and an isthmus,
produces two hormones T3/T4 ,
Calcitonin = calcium and phosphorus metabolism
100
explain structure of thyroid gland
follice cells which produce thyroglobulin forming a colloid lumen
parafollicular c cells produce calcitonin
101
Explain the production of T3/T4
Follicular cells make enzymes and thyroglobulin for colloid cells
Iodine is co transported into cell with na to reach colloid
iodine + thyroglobulin= t3/t4
thyroglobuln taken back into cell
intracellular enzymes separate t3/t4 from protein
t3/t4 free to enter blood stream
102
in Binding selectivity, what do nuclear receptor for TH prefer to bind to and why
T3 because it is more potent
103
what does T3 deficeincy cause
hypothyroidism
104
whats the role of t4
pro hormone
105
what is a prohormone
precursor of a hormone,
doesnt make much of aneffect by itself, travelling in blood in inactive form
106
what does t4 act as
a reservior
107
compare half lives of t3 and t4
t3 half life very short, t4 5-7 more stable than t3
108
what are the action of t3 + t4?
Control basal metabolism rate = increasing oxygen and energy consumption at rest
in fetal development, promotes protein synthesis growth and skeletal maturation
109
what can a deficiency in t3/t4 lead to
cns damage if not corrected by mid gestation
110
list some effects of t3/t4 deficiencies
tremors/nervousness hyperactivity/decrease in blood cholesetrol / increased temperature
111
describe the effects of calcitonin in regulating calcium levels
secreted from thyroid parafollicular c cells = slows down the calcium releasing activity of osteoclasts in bone
112
what is a goitre
swelling of thyroid gland= lump in neck, caused by iodine deficiency= hyper/hypo thyroidism
113
what is hyperthyroidsim
overactive thyroid, too much thyroid
causes unexplained, unplanned weight loss nervousness and anxiety, hyperactivity
114
what is the cause of graves disease
IgG antibodies produced against the thyrotropin receptor= mimc action of tsh=stimulation of gland= uncontrolled production of t3/t4
115
what are the cellular changes related to grave's disease
hypertrophy/hyperplasia
116
what effect do autoantibody receptors have on hormone synthesis
unregulated/overproduction of thryoid hormones
117
what are the causes of hypothyroidism
surgery of glands and inflammation of thyroid gland
118
explain what is meant by inflammation of thyroid gland
large percent of cells damaged or dead= not enough hormone produced
119
what is hashimoto's thyroiditis
auto immune thyroiditis= thyroid inflamed as aresult of immune system attacking itself
120
what are some symptoms of hyperthyroidism
muslce fatigue, problems sleeping,nervousness
121
what are the treatments for hyperthyroidism
antithyroid methimazole +propylthiouracil = stop thyroperoxidase which is required for addition of iodine to tyrosine
radioactive iodine
beta blockers for symptome control
surgery= thyroidectomy
122
what are some symptoms of hypothyroidism
depression, cold intolerance , tiredness
123
what are the treatments for hypothryoidism
levothyroxine, manufactured form of t4
123
where are parathyroid glands located
on posterior surface of thyroid gland
123
what is the function of cheif cells
produce PTH (parathyroid hormone and peptide hormone)
123
what type of cells are in parathyroid glands
chief and oxyphil cells
124
what is the function of PTH
maintains blood conc of ca2+,
when blood calcium is low, stimulates osteoclats to release ca2+ from bone = lower secretion of ca2+ by kidney= activates vitamin d which stimulates uptake of ca2+ from intestine
125
what is the main cause of hypoparathyroidism
low calcium and low pth
126
what is the cause of hyperparathyroidism
low calcium, high levels of PTH
127
what is the cause of Independent Hypercalcemia
high calcium levels, low PTH levels
128
what is the cause of hyperparathyroidism
high calcium and PTH
129
where are adrenal glands located
top of kidney
130
what is the difference between adrenal cortex and medulla
cortex=outer
medula = inner
131
what is aldosterone
steroid hormone synthesised in adrenal cortex in response to a decline in either blood volume or blood pressure
132
where is the the action site for aldosterone
principal cells of the cortical distal tubules and collecting duct
133
what is the effect of aldosterone
kidneys retain na+ and water reabsorption
k+ secretion
134
what is the mechanism of action for aldosterone
a combines with cytoplasmic receptor
starts transcription in nucleus
new protein channels and pumps made
aldosterone induced proteins modify existing proteins
= increased na reabsorption and k+ secretoion
135
explain the hormone cortisol
glucocorticoid, essential for life, helps body deal with stressful situations within minutes
regulates cardiovascular, metabolic, immunologic and homeostatic body function
136
what is the role of cortisol on the brain
keeps glucose levels high enough to support brain activity
forces other body cells to switch to fats and amino acid for energy
catabolic=breakdown protein
137
how does cortisol affect immune system
redirects circulating lymphocytes to lymphoid and peripheral tissues
can depress immune and inflammatory response = therapeutic use
138
what happens in the stress cycle
hypo releases CRH anterior releases ACTH
ACTH goes to adrenal cortex= glucocorticoid secretion
DHEA converted in peripheral tissues to testosterone and estrogen + steroid hormones
139
what is a cause of excess secretion of cortisol
cushings syndrome, caused by ACTH secreting pit tumour
140
what happens when cortisol production reduced
addisons disease = low cortisol, aldosterone, blood glucose and sodium
141
what are the symptoms of cushing syndrome
red round face, obesity,skin ulcers, muslce wasting
142
what are the symptoms of addisons diseas
hyperpigmentation, low blood sugar, adrenal crisis
143
