Endocrine Adrenal gland And Pancreas. Adrenal gland Structure Cortex ◦ Glucocorticoids Chemical nature Effects Control of secretion ◦ Mineralocorticoids.

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