Adrenal Gland Physiology (Dr
-
Upload
api-3769252 -
Category
Documents
-
view
135 -
download
4
Transcript of Adrenal Gland Physiology (Dr
ADRENAL GLAND
PHYSIOLOGY
AnatomyAnatomy
Adrenal CortexAdrenal Cortex
phenylethanolamine-N-
methyltransferase
Norepinephrine Epinephrine
Adrenal Medulla
Steroidogenesis
Steroidogenesis
Steroidogenesis
Steroidogenesis
Congenital Adrenal Hyperplasia
- autosomal recessive disorder due to deficiency or lack of an enzyme in the synthesis of cortisol
Steroidogenesis
Steroidogenesis
Steroidogenesis3 dehydrogenase
Steroidogenesis 17 hydroxylase
Steroidogenesis 21- hydroxylase
Steroidogenesis 11- hydroxylase
Steroidogenesis
Synthesis & ReleaseSynthesis & Release
Transport Proteins
Corticosteroid-binding globulin (CBG)
Albumin
Transport & MetabolismTransport & Metabolism
Cortisol Aldosterone
80% bound to CBG 60% bound to albumin
15% bound to albumin
5% free 40% free
t½ 90 mins t ½ 30 mins
Serum levels:
10-25μg/dl 2-10 ng/dl
Transport & MetabolismTransport & Metabolism
Transport & Metabolism
Hypothalamus
CRH
Pituitary
ACTH
Adrenal Cortex
CORTISOL
Regulation - GlucocorticoidsRegulation - Glucocorticoids
Regulation - Glucocorticoids
Regulation - Glucocorticoids
Regulation-Glucocorticoids
Regulation-Glucocorticoids
Mechanism of Action-Glucocorticoids
Biologic Actions-Glucocorticoids
Interaction of Hormones in Metabolism
post-prandial: regulatory hormone (insulin)
cellular glucose uptake
early fasting: counter-regulatory hormones (E,G,GH,C)
glycogenolysis; minimal glycolysis
late fasting: counter-regulatory hormones (E,G,GH,C)
gluconeogenesis; lipolysis; protein degradation
long-term starvation
ketogenesis
Biologic Actions-GlucocorticoidsBiologic Actions-Glucocorticoids
Interaction of Hormones in Metabolism
long-term starvation: normal levels of counter-regulatory
hormones
ketogenesis
protein degradation
gluconeogenesis
BMR
Biologic Actions-GlucocorticoidsBiologic Actions-Glucocorticoids
Biologic Actions-Glucocorticoids
Biologic Actions-Glucocorticoids
Physiologic Effects
1. hepatic glucose production
2. protein catabolism
3. fat catabolism
4. increased bone resorption
5. altered mood
6. increased gastric acidity
7. PNMT synthesis
Biologic Actions-GlucocorticoidsBiologic Actions-Glucocorticoids
Therapeutic Effects
1. prevents vascular collapse during stress
2. anti-inflammatory effect
Capillary dilation; prostaglandin/leukotriene production; Leukocyte migration; stabilzation of lysosomal membrane
3. invoking immunosuppression
- T cell proliferation; complement synthesis; cell killing
Biologic Actions-GlucocorticoidsBiologic Actions-Glucocorticoids
BBaacckk ttoo HHuummaann PPhhyyssiioollooggyy hhoommee ppaaggee
BBaacckk ttoo lliisstt ooff cchhaapptteerrss
FFiigguurree 1122..11
FFiigguurree 1122..22
FFiigguurree 1122..33
FFiigguurree 1122..44
FFiigguurree 1122..55
FFiigguurree 1122..66
FFiigguurree 1122..77
FFiigguurree 1122..88
FFiigguurree 1122..99
FFiigguurree 1122..1100
FFiigguurree 1122..1111
FFiigguurree 1122..1122
FFiigguurree 1122..1133
FFiigguurree 1122..1144
FFiigguurree 1122..1155
FFiigguurree 1122..1166
FFiigguurree 1122..1177
FFiigguurree 1122..1188
FFiigguurree 1122..1199
FFiigguurree 1122..2200
FFiigguurree 1122..2211
FFiigguurree 1122..2222
FFiigguurree 1122..2233
FFiigguurree 1122..2244
FFiigguurree 1122..2255
FFiigguurree 1122..2266
Biologic Actions-Glucocorticoids
Pathophysiology
Pathophysiology
Pathophysiology
Pathophysiology
Pathophysiology
Pathophysiology
Regulation-MineralocorticoidsRegulation-Mineralocorticoids
Stimuli for Renin Secretion
blood pressure
serum Na
blood volume
4. ANS stimulation
Regulation-MineralocorticoidsRegulation-Mineralocorticoids
Regulation-Mineralocorticoids
Actions of Angiotensin II
1. Direct arteriolar vasoconstrictor
2. Stimulus to aldosterone secretion
Regulation-Mineralocorticoids
Regulation-Mineralocorticoids
Aldosterone
MOA: transcription of enzymes and proteins
Major actions: Na reabsorption in distal tubule
Extrarenal effects: Na reabsorption in saliva, sweat, stool
Biologic Actions-MineralocorticoidsBiologic Actions-Mineralocorticoids
Hypersecretion of Aldosterone
1o aldosteronism – Conn’s syndrome
2o aldosteronism – liver/kidney disease
SXS: hypertension
hypokalemia
metabolic alkalosis
PathophysiologyPathophysiology
Primary Hyperaldosteronism
ECF volume Aldosterone Na retention + Renin
Renal perfusion pressure
Secondary Hyperaldosteronism
Na retention Renal perfusion Renin Aldosterone + pressure ECF volume
PathophysiologyPathophysiology
Hyposecretion of Aldosterone
1o hyposecretion – Addisons’ dse
2o hyposecretion – kidney damage
SXS: hypovolemia
hyponatremia
hyperkalemia
PathophysiologyPathophysiology
Happy New Year!!!
Anatomy
AnatomyAnatomy
Back to Human Physiology home page
Back to list of chapters
Figure 12.1
Figure 12.2
Figure 12.3
Figure 12.4
Figure 12.5
Figure 12.6
Figure 12.7
Figure 12.8
Figure 12.9
Figure 12.10
Figure 12.11
Figure 12.12
Figure 12.13
Figure 12.14
Figure 12.15
Figure 12.16
Figure 12.17
Figure 12.18
Figure 12.19
Figure 12.20
Figure 12.21
Figure 12.22
Figure 12.23
Figure 12.24
Figure 12.25
Figure 12.26
Synthesis & Release
Epinephrine Norepinephrine
t½ < 10 sec t½ < 15 sec
levels 20-50ng/ml 100-350 ng/ml
Transport & MetabolismTransport & Metabolism
Transport & Metabolism
Stimuli for Catecholamine Secretion
1.exercise, stress and anxiety
2. hypoglycemia
3. emergency situations
4. decreased blood pressure
5. decreased oxygen availability
RegulationRegulation
Mechanism of Action of Catecholamines
receptors : stimulates adenylate cyclase
receptors : inhibits adenylate cyclase
Biologic ActionsBiologic Actions
Biologic Actions
Factors Involved in Activation of Sympathetic Response
Sympathoadrenal System Sympathetic Nervous System
Signal Input Ach from preganglionic n Ach from preganglionic neuron
Major Secretory Epinephrine Norepinephrine product
Stimuli for psychological stress, anxiety cold stress, exercise, activation hypoxia, hypoglycemia postural hypotension
Major PSIO first line of defense vs first line of defense vs stress effect stress (fight or flight) normal homeostatic
maintenance of CV sympathetic tone
Hormonal kidney and liver presynaptic neuron (reuptake) metabolism (metabolism)
Biologic ActionsBiologic Actions
Major Physiologic Effects:
cardiac output
2. respiration
3. blood flow to heart, muscles, brain, lungs
4. alertness
5. circulating glucose, FFA, lactic acid
Biologic ActionsBiologic Actions
Sympathetic Response “Fight of Flight”
Tissue Direct Response Physiological Outcome
Lungs respiration O2 to heart
Heart cardiac output blood/O2 to tissues
Vascular +/- regional blood preferential shunting of smooth muscle flow blood
Skeletal contraction locomotion muscle
Liver glycogenolysis glucose to tissues
Adipose tissuelipolysis FFA to tissues
Biologic ActionsBiologic Actions
Disorders of Adrenal Medulla
hyposecretion – hypofunction of adrenal gland
hypersecretion – benign pheochromocytoma; malignant neuroblastoma
SXS: hypertension tremors tachycardia anxiety headache sweating
PathophysiologyPathophysiology
Therapeutic Uses of Catecholamines
Agonists Antagonists
Parkinson’s disease hypertension clinical depression hyperthyroidism shock cardiac arrhythmia asthma angina pectoris allergic reactions nasal congestion
PathophysiologyPathophysiology
THANK YOU!