endocrine adrenal gland and pancreas. adrenal gland structure cortex ◦ glucocorticoids chemical...
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EndocrineEndocrineAdrenal gland AndPancreas
Adrenal glandAdrenal glandStructureCortex
◦Glucocorticoids Chemical nature Effects Control of secretion
◦Mineralocorticoids Effects Control of secretion
Medulla◦Catecholamines
Adrenal glandAdrenal gland
Adrenal cortexAdrenal cortexAdrenal cortex
◦80% of an adrenal gland’s total weight
◦Zona glomerulosa Mineralocorticoids
◦Zona fasciculata Glucocorticoids
◦Zona reticularis Androgens
Adrenal cortexAdrenal cortexCortex
◦ Activity stimulated by ACTH (regulates mainly glucocorticoids & androgens).
Cortical hormones◦ Mineralcorticoids
Aldosterone regulate salt and water balance
◦ Glucocorticoids Cortisol regulate glucose metabolism and the immune system.
◦ Gonadocorticoids Androgens Estrogens
Adrenal cortexAdrenal cortexGlucocorticoid hormones
Most potent naturally occurring glucocorticoids is cortisol
They are carried by plasma proteins: albumin and globulin.
Only 2% are not bound, free in the circulation and are biologically active.
It shows diurnal variation; increases early morning and decreases at night.
Effects of cortisolEffects of cortisolOn carbohydrates
◦Stimulation of gluconeogenesis by the liver
◦ Increase in glycogen storage in liver cells ◦Decreased glucose utilization by the cells
On protein◦ Catabolic effect in all body cells except the liver◦ Mobilization of amino acids from muscles.◦ Decreased protein synthesis
On fat◦ Mobilization of fatty acids from adipose tissue
Effects of cortisolEffects of cortisolAnti-inflammatory
◦Stabilizes lysosomal membrane◦Reduces degree of vasodilatation◦Decreases permeability of capillaries◦Decreases migration of white blood
cells◦Suppresses immune system
On blood cellsOn blood cellsIncrease RBCsDecrease lymphocytes &
eosinophils.Increase neutrophils.Skin
Decrease collagen & protein synthesis.Decrease fibroblast proliferation and healing.
BoneBoneInhibit bone matrix formation.Anti-vitamin D effect on bones
GIT:Increases HCL formation.
Abnormal high cortisol Abnormal high cortisol levellevel
Cushing’s sydndrome
Causes◦Pharmacologic◦Pituitary adenoma
75-90%◦Adrenal adenoma,
carcinoma◦Ectopic ACTH
Characteristics of Cushing’s Characteristics of Cushing’s diseasediseaseHyperglycemiaHypertension (Salt & water
retention).Moon face, buffalo neck, abdominal
obesity, thin limbs, due to redistribution of fat and lipolytic effect and catabolic effect on proteins.
Increased susceptibility to infection.Frequent fractures.
Adrenal cortexAdrenal cortexMineralocorticoid hormones:
Aldosterone
Most potent naturally occurring mineralocorticoid is aldosterone
Effects: Affect ion transport by epithelial cells
Increase the activity of the sodium pump of the epithelial cells; distal tubules of the nephron, sweat glands, salivary & intestinal glands.
Cause sodium retention and potassium and hydrogen loss by the kidney. Water is secondarily absorbed following sodium.
Regulated by the renin-angiotensin system
AldosteroneAldosterone
Regulation of secretionRegulation of secretion• Angiotensin IIAngiotensin II
• SSK K (serum potassium conc.)(serum potassium conc.)Major modulators
Minor regulators:
ACTH
Serum sodium
Regulation of Aldosterone Regulation of Aldosterone secretionsecretion
Adrenal medullaAdrenal medulla
•Adrenal medullaInnervated by the sympathetic nervous system& secretes nor-adrenallin
Endocrine function of Endocrine function of pancreaspancreas
PancreasPancreas
EndocrineEndocrine ExocrineExocrine
Islets of LangerhansIslets of LangerhansClusters of cells scatteredClusters of cells scattered between the acinibetween the acini4 types of cells4 types of cells
Endocrine PancreasEndocrine Pancreas
Major cell types of the Islets of Langerhans Major cell types of the Islets of Langerhans and the Hormones they produceand the Hormones they produce
NameName Hormone producedHormone produced Percentage of Percentage of total Islet*total Islet*
Alpha cellAlpha cell
Beta cellBeta cell
Delta cellDelta cell
F cellF cell
GlucagonGlucagon
InsulinInsulin
SomatostatinSomatostatin
Pancreatic polypeptidePancreatic polypeptide
2525
6060
1010
11
*The remaining 4% consists of connective *The remaining 4% consists of connective tissue and blood vessels.tissue and blood vessels.
Endocrine PancreasEndocrine Pancreas
Insulin◦Secretion is promoted by increased
blood glucose levels.◦Facilitates the rate of glucose uptake
into the cells of the body& decrease blood sugar level.
◦Anabolic hormone: Synthesis of proteins,
◦Lipogenic: (+)lipids formation in adipose tissues& inhibit lipid breakdown by lipase
Blood glucoseBlood glucose
Cells in Cells in pancreatic pancreatic
isletsislets
Insulin Insulin secretionsecretion
Cellular uptake Cellular uptake of blood glucoseof blood glucose Blood glucoseBlood glucose
GlucoseGlucose
GlycogenGlycogen
GlucoseGlucose
TriglycerideTriglyceride
Liver and Liver and skeletal muscleskeletal muscle
Adipose Adipose tissuetissue
Effects of Effects of InsulinInsulin
Endocrine Pancreas, cont,….Endocrine Pancreas, cont,….
Glucagon◦Secretion is promoted by decreased
blood glucose levels◦Stimulates glycogenolysis,
gluconeogenesis, and lipolysisSomatostatin
◦Possible involvement in regulating alpha and beta cell secretions
Cause Cause
Inadequate secretion of insulin
Defects in the action of insulin
Metabolic disturbances (hyperglycemia and hyperglycemia and
glycosuria)glycosuria)
Types of DiabetesTypes of Diabetes
Type 1Type 1 DiabetesDiabetesAffects childrenAffects children
CauseCause:: inadequate inadequate insulin insulin secretionsecretion
Treatment :Treatment : insulin insulin injectioninjection
Type 2Type 2 diabetesdiabetes
Affects adultsAffects adults
CauseCause defect in defect in insulin actioninsulin action
Treatment : Treatment :
diet or OHAdiet or OHA