adrenal gland physiology Flashcards
1
Q
how many adrenal glands are there
A
2
2
Q
where are the adrenal glands
A
one above each kidney
3
Q
what are the adrenal glands composed of
A
two endocrine organs one surrounding the other
4
Q
what does the outer layer of adrenal gland compose
A
adrenal cortex
5
Q
what does the adrenal cortex secrete
A
steroid hormones
6
Q
what are the inner parts of the adrenal glands
A
adrenal medulla
7
Q
what does the adrenal medulla secrete
A
catecholamines
8
Q
what are the 3 layers of the adrenal cortex
A
- zona glomerulosa - zona fasciculata - zona reticularis
9
Q
what is the outer layer of the adrenal cortex
A
zona glomerulosa
10
Q
what is the middle layer of the adrenal cortex
A
zona fasciculata
11
Q
what is the inner most layer of the adrenal cortex
A
zona reticularis
12
Q
what does the adrenal cortex produce
A
a number of different adrenocortical hormones
13
Q
what are all steroids derived from
A
cholesterol
14
Q
what is the main mineralocorticoid
A
aldosterone
15
Q
what is the main glucocorticoid
A
cortisol
16
Q
what does cortisol play a major role in
A
glucose metabolism
17
Q
what are sex hormones similar to
A
similar to those produced by the gonads (testes in males, ovaries in females)
18
Q
what part of the adrenal cortex produces aldosterone
A
zona glomerulosa
19
Q
where is cortisol synthesised
A
limited to the two inner layers of the adrenal cortex
20
Q
where is the major source of glucocorticoid
A
zona fasciculata
21
Q
are the adrenocortical hormones lipophilic
A
yes
22
Q
how are the adrenocortical hormones carried
A
in the blood bound to plasma proteins
23
Q
what is cortisol bound to mostly
A
plasma protein corticosteroid-binding-globulin
24
Q
what is aldosterone mostly bound to
A
albumin
25
does each adrenocorticol steroid hormone bind to its own specific hormone
yes
26
where is the principle site of aldosterone action
distal and collecting tubules of the kidney
27
what is the effect of aldosterone
promotes sodium retention and enhances potassium elimination during the formation of urine
28
what does cortisol play an important role in
- carbohydrate, protein and fat metabolism - hormonal activities - helps resist stress
29
what is the overall effect of cortisol metabolically
increase the concentration of blood glucose at the expense of protein and fat stores
30
cortisol and gluconeogenesis
stimulates it
31
cortisol and glucose uptake
inhibits glucose uptake - but not in the brain
32
cortisol and lipolysis
facilitates it - releasing fatty acids
33
what is cortisol important for
permit the catecholamines to induce vasoconstriction - if lacking cortisol a patient may go into shock in a stressful situation that demands vasoconstriction
34
what does cortisol play a key role in
stress
35
cortisol and the immune system
- anti-inflammatory - immunosuppressive
36
what inflammatory mediators does cortisol partially block
- prostaglandin - leukotrienes
37
how does cortisol affect the neutrophils
suppresses migration of neutrophils to the site of inflammation
38
what can lymphocytes secrete
ACTH
39
cortisol and the immune system
dampens its affects
40
what can be administered to inhibit the inflammatory response
glucocorticoids
41
what are glucocorticoids good at treating
rheumatoid arthritis
42
how should glucocorticoids be administered
sparingly
43
why should glucocorticoids be given sparingly
- patient has limited ability to resist infection - troublesome side effects - suppresses the hypothalamus
44
side effects of glucocorticoids
- GI ulcers - high blood pressure - atherosclerosis - menstrual irregularities - bone thinning
45
REGULATION OF CORTISOL
REGULATION OF CORTISOL
46
what secreted cortisol
adrenal cortex
47
how is secretion of cortisol regulated
negative feedback
48
what tare the steps of cortisol secretion
1. ACTH from anterior pituitary corticotropes 2. acts through cAMP 3. stimulates the adrenal cortex to secrete cortisol
49
what happens when ACTH is reduced
the zona fasciculata and zona reticualris shrink considerably and cortisol secretion is reduced
50
what maintains the size of the zona glomerulosa
angiotensin
51
what enhances the synthesis of cortisol
ACTH
52
specific influences of ACTH on cortisol production
1. ACTH mobilises cholesterol from the lipid droplets in the zona fasciulata and reticularis 2. increases the production of pregneneolone from cholesterol 3. increases production of enzymes needed to convert pregneolone into cortisol
53
what causes ACTH release
corticotropin-releasing hormone (CRH) from the hypothalamus
54
how does CRH stimulate corticotropes
via cAMP
55
what 2 factors influence cortisol concentration
- diurnal rhythm - stress
56
what kind of rhythm does cortisol display
diurnal rhythm
57
when is the highest level of cortisol
morning
58
when is the lowest level of cortisol
night
59
what increases cortisol level
stress
60
HORMONES
HORMONES
61
what does adrenal cortex produce in females
estrogens
62
what does adrenal cortex produce in males
androgens
63
where is the main site of production of sex hormones
gonads - testes males - ovaries females
64
does each sex only produce their specific hormones
no they both have a small amount of the other
65
what converts testosterone into oestrogen
aromatase
66
where is aromatase found
adipose tissue
67
what is the only adrenal sex hormone that has biological importance
androgen dehydroepiandrosterone (DHEA)
68
does ACTH control adrenal gland androgen secretion
yes
69
ADRENAL CONDITIONS
ADRENAL CONDITIONS
70
what hormones can be overstimulated
- aldosterone - cortisol - adrenal
71
what can cause excessive mineralocorticoid secretion
- hyper-secreting adrenal tumour - inappropriately high activity of renin angiotensin aldosterone system
72
example. of excess mineralocorticoid secretion diseases
- atherosclerotic narrowing of renal arteries
73
symptoms of hyperaldosteronism
- hypernatremia (Na+ retention) - hypokalaemia (K+ depletion) - hypertension
74
what is cortisol hypersecretion call
Cushings syndrome
75
what can cause Cushings syndrome
- overstimulation of adrenal cortex by excessive amounts of ACTH - adrenal tumours that secrete cortisol - ACTH secreting tumours located in places other than the pituitary
76
what are the symptoms of Cushings caused by
exaggerated effects of glucocorticoids
77
what happens when too many amino acids are converted into glucose
high blood glucose (mimics diabetes mellitus)
78
where is the extra glucose deposited
- as body fat - abdomen - above shoulder blades - face
79
what are the excess glucose depositions called
- buffalo hump - moon face
80
what does loss of muscle protein lead to
muscle weakness and fatigue
81
what does loss of structural protein in blood vessels lead to
easy bruisability
82
what is adrenal androgen secretion condition
masculinising condition
83
what do androgen exert
masculinising effects
84
what happen when a women has androgen secretion
develop male pattern of body hair
85
what is it called when a women has a male pattern body hair
hirtuism
86
what are other symptoms of androgen secretion
- deepening of the voice - muscular arms and legs - smaller breast - menstruation may cease
87
what happens if a newborn female has adrenogenital syndrome
they have male type external genitalia
88
why do newborn females get male genitalia
as the clitoris enlarges under androgen influence and takes on a penile appearance
89
what is it called when the female ovaries are present but the external genitalia resemble those of a male.
female psueodhermaphroditism
90
what is it when pre pubertal males have excessive androgen secretion
- deep voice - beard - enlarged penis - sex drive
91
what is it called when a pre pubertal male has excessive androgen
precocious pseudopuberty
92
in pseudopuberty do the males develop sperm
no as the testes are still in their non-functional prepubertal state
93
does excess androgen stimulation in males have an effect
not really
94
what is adrenogenital syndrome most commonly caused by
inherited enzymatic defect in the cortisol steroidogenic pathway
95
how to treat cortisol deficit with ACTH increase
glucocorticoids - replaces cortisol deficit - inhibits hypothalamus and pituitary so that ACTH secretion is suppressed
96
ADRENOCORTICAL INSUFFICIENCY
ADRENOCORTICAL INSUFFICIENCY
97
what happens if one adrenal gland is non-functional or removed
the other healthy organ takes over the function of both
98
if one gland is affected then the patient has adrenocortical insufficiency true or false
false both glands must be affected as if one gland is non-functional then the other hypertrophies
99
what is another name for primary adrynocortical insufficiency
Addison disease
100
what is the problem in Addison disease
all layer of the adrenal cortex are under secreting
101
what is the common cause of Addison
autoimmune destruction of the cortex
102
why may secondary adrenocortical insufficiency occur
because of a pituitary or hypothalamic abnormality - results in insufficient ACTH secretion
103
is Addison disease fatal
yes
104
is aldosterone essential for life
yes
105
what do patients with aldosterone deficiency present with
- K+ retention (hyperkalaemia) - Na+ depletion (hyonatremia)
106
what does K+ retention cause
cardiac abnormality
107
symptoms of Addison
- poor response to stress - hypoglycaemia - lack of permissive action for metabolic activities - hyperpigmentation
108
why does hyperpigmentation occur in Addison
high levels of ACTH can bind with alpha-melanocyte stimulating hormone causing darkening of the skin
109
ADRENAL MEDULLA
ADRENAL MEDULLA
110
what does sympathetic pathway consist of
two neurons in sequence
111
what is the neurotransmitter released by the sympathetic post ganglionic fibre
norepinephrine
112
what receptors do norepinephrine bind to
adrenergic receptors
113
what does the adrenal medulla consist of
modified postganglionic sympathetic neurons called chromaffin cells
114
what happens when chromaffin cells stimulated
they release their chemical transmitter directly into circulation
115
what is the norepinephrine called that is released from the adrenal medulla
epinephrine
116
what class do epinephrine and norepineprhine belong to
catecholamines
117
what are catecholamines derived from
amino acid tyrosine
118
where is catecholamines synthesised
entirely within the cytosol of the adrenomedullary secretory cells
119
once produced where are catecholamines stored
in chromaffin granules
120
how are catecholamines secreted into the blood
by exocytosis of chromaffin granules
121
what's most abundant epinephrine or norepinephrine
epinephrine
122
where is epinephrine produced
adrenal medulla
123
what are the 4 receptors for epinephrine and norepinephrine
- alpha 1 - alpha 2 - beta 1 - beta 2
124
what does norepinephrine bind predominantly with
alpha and beta 1
125
what does epinephrine activate
beta 2 receptors
126
where are beta 2 receptors
- skeletal muscles
127
what is the overall function of epinephrine
reinforce the sympathetic nervous system
128
what support peak physical exertion and stress
sympathetic nervous system and epinephrine
129
does epinephrine have a role in blood pressure
yes
130
does norepinephrine dilate the airways
nope
131
does epinephrine and norepinephrine stimulate bladder emptying
no they inhibit bladder emptying
132
epinephrine effect on blood glucose
increase it
133
epinephrine and insulin
inhibits insulin
134
epinephrine is responsible for rest and digest
no fight or flight
135
can the brain use fatty acids for energy
no
136
epinephrine increase heart rate true or false
true
137
epinephrine causes swathing true or false
true
138
epinephrine constricts the pupils true or false
false dilate pupils
139
what is catecholamine secretion by the adrenal medulla controlled by
sympathetic input into the gland
140
how much can epinephrine be increased during stress
300 times
141
diagram
142
diagram
143
diagram
