endocrine system n.
Skip this Video
Download Presentation
Endocrine System

Loading in 2 Seconds...

play fullscreen
1 / 62

Endocrine System - PowerPoint PPT Presentation

  • Uploaded on

Endocrine System. Glands and Hormones. Definitions. Hormones are chemicals regulators, secreted into the blood, that affect the functioning of other cells These “other cells” are called target cells

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Endocrine System' - derek-levine

Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
endocrine system

Endocrine System

Glands and Hormones

  • Hormones are chemicals regulators, secreted into the blood, that affect the functioning of other cells
  • These “other cells” are called target cells
  • Hormones are specific for certain targets because hormones bind to specific receptors of target cells
hormones regulate
Hormones Regulate
  • Growth
  • Metabolism
  • Fluid and electrolyte
  • Acid-base balance
  • Reproduction
  • Blood pressure
endocrine glands and tissues
Endocrine Glands and Tissues
  • Secrete hormones Examples
    • Pituitary gland (hypophysis)
    • Thyroid gland
    • Parathyroid glands
    • Adrenal glands
    • Pancreas
    • Gonads
    • Endocrine tissues within other organs
chemistry of hormones
Chemistry of hormones
  • Compounds that act as hormones are:
    • Steroids (derived from cholesterol)
    • Amines (derived from a single amino acid)
    • Peptides (smaller chains of amino acids)
    • Proteins (polypeptide chains of amino acids)
    • Glycoproteins (protein/carbohydrate complex)
hormone secretion
Hormone Secretion




Hormone secretion




Target cell

control of secretion
Control of Secretion
  • Negative feed back
    • Stimulus is decreased or inhibited by some factor such as concentration of hormone
    • Attempts to maintain normal levels of secretion
  • Positive feed back
    • Stimulus for secretion is increased or exaggerated
pituitary gland hypophysis
Pituitary Gland (Hypophysis)
  • Small gland connected to hypothalamus
  • Two parts
    • Anterior pituitary (adenohypophysis)
    • Posterior pituitary (neurohypophysis)



posterior pituitary---------

-------anterior pituitary

pituitary gland
Pituitary Gland
  • Posterior pituitary derived from neural brain tissue and connects to hypothalamus by the stalk-like hypothalamic hypophyseal tract
  • Anterior pituitary from ectodermal tissue in the roof of embryonic mouth.


pituitary gland1
Pituitary Gland
  • Posterior pituitary secretes two hormones
    • Hormones produced by hypothalamus and placed in posterior pituitary for secretion
  • Anterior pituitary largest part
    • Produces and secretes most of the hormones
    • Under direct control of hypothalamus
      • Hypothalamus secretes releasing and inhibiting hormones that reach anterior pituitary through hypophyseal portal circulation.
hormones of the posterior pituitary
Hormones of the Posterior Pituitary
  • Oxytocin (OT)
    • Target tissues are smooth muscles of reproductive system of both sexes
    • Actions in female
      • Labor (uterine) contractions
      • Release of milk from mammary glands (milk letdown)
    • Actions in male
      • Contraction of smooth muscle in reproductive tissue
hormones of posterior pituitary
Hormones of Posterior Pituitary
  • Antidiuretic Hormone (ADH) (vasopressin)
    • Target tissues are kidneys, sweat glands and arterioles
    • Actions
      • Causes kidneys and sweat glands to conserve water
      • Causes vasoconstriction of arterioles
hormones of anterior pituitary
Hormones of Anterior Pituitary
  • Human Growth Hormone (hGH)
    • Targets all cells especially skeletal and muscle tissue
    • Actions
      • Promotes secretion of insulin-like growth factors (IGFs) within target tissues
      • IGFs increase: -rate of cell division for growth

-protein synthesis needed for growth

-use of fat for energy

      • Results in growth to adulthood and maintenance of skeleton and muscles in adults
hormones of the anterior pituitary
Hormones of the Anterior Pituitary

Human Growth Hormone Imbalances

  • Pituitary dwarfism caused by hyposecretion in children and adolescents resulting in small body
  • Giantism caused by hypersecretion in infants and children resulting in height of over 8 feet
  • Acromegaly caused by hypersecretion in adults resulting in distorted facial features
hormones of anterior pituitary1
Hormones of Anterior Pituitary
  • Thyroid stimulating hormone (TSH)
    • Targets thyroid gland
    • Stimulates secretion of the thyroid hormones
  • Adrenocorticotropic Hormone (ACTH)
    • Targets Adrenal cortex
    • Stimulates secretion of glucocorticoids from adrenal glands
hormones of anterior pituitary2
Hormones of Anterior Pituitary
  • Prolactin (PRL)
    • Targets mammary glands
    • Stimulates milk production in mammary glands in concert with other hormones
  • Gonadotropins
    • Follicle Stimulating Hormone (FSH) and
    • Luteinizing Hormone (LH)
    • Target the ovaries and testes (gonads)
    • Control female and male reproductive physiology
control of secretion of anterior pituitary hormones
Control of Secretion of Anterior Pituitary Hormones
  • Secretion Stimulated by releasing hormones (RH’s) from hypothalamus through hypophyseal portal system
  • Secretion suppressed by inhibiting hormones (IH’s) from hypothalamus through hypophyseal portal system
  • All controlled by negative feedback
thyroid gland
Thyroid Gland
  • Large butterfly-shaped gland in neck below voice box (larynx)
  • Has Two lobes connected by an isthmus

--------left lobe

right lobe-----


thyroid follicle-----

histology of thyroid
Histology of Thyroid
  • Composed of many follicles filled with jelly-like (colloidal) thyroglobulin protein
  • Thyroid hormones T3 and T4 synthesized by follicle cells and stored in combination with thyroglobulin

Thyroglobulin with T3 and T4

thyroid hormones
Thyroid Hormones
  • T3 short for triiodothyronine
  • T4 short for tetraiodothyronine (thyroxine)
thyroid hormones1
Thyroid Hormones
  • Formed by addition of iodine to the thryroglobulin
  • 3 & 4 stands for number of iodines
secretion of t 3 t 4
Secretion of T3 & T4
  • Synthesis and secretion stimulated by anterior pituitary hormone TSH
  • Portion of stored thyroglobulin taken in from colloid by follicles cells
  • Colloid digested by lysosomes releasing T3 & T4
  • T3 & T4 enter blood, combine with transport proteins and are transported to target cells
target cells and actions of t 3 t 4
Target Cells and Actions of T3 & T4
  • Actions
    • ATP production by mitochondria (aerobic cell respiration)
    • Normal growth
  • Control by negative feedback
thyroid and negative feedback
Thyroid and Negative Feedback
  • Increase in blood levels of T3 & T4 etc.
  • Release of thyrotropin releasing hormone (TRH) inhibited
  • Release of thyroid stimulating hormone (TSH) inhibited
  • Secretion of T3 & T4 decreases
imbalances of t 3 t 4
Imbalances of T3 & T4
  • Thyroid dwarfism (Cretinism)
    • Too little secretion of thyroid hormones during fetal development and infancy.
    • Severe forms of mental and physical retardation in the newborn.
    • Retardation is reversible if hormonal replacement therapy is started during the first four months of life.
imbalances of t 3 t 41
Imbalances of T3 & T4
  • Hypothyroidism (in adults)
    • Too little T3 & T4
    • Symptoms
      • MR
      • bradycardia
      • BT
      • lethargy
      • goiter
      • weight gain
      • cold intolerance
      • myxedema
imbalances of t 3 t 42
Imbalances of T3 & T4
  • Hyperthyroidism (in adults)
    • Too much T3 & T4
    • Grave’s disease most common form
    • Symptoms
      • MR
      • tachycardia
      • BT
      • anxiety & irritability
      • goiter
      • Exophthalmia (exophthalmos)
      • heat intolerance
      • weight loss
imbalances of t 3 t 43
Imbalances of T3 & T4
  • Endemic goiter and iodine deficiency
    • Insufficient dietary iodine to make T3 & T4
    • Endemic means localized or regional
    • Lack of negative feedback from T3 & T4 causes over stimulation and overgrowth of the thyroid gland.
    • Goiter results (enlarged thyroid gland)
thyroid disorders
Thyroid Disorders


Endemic Goiter

control of blood calcium
Control of Blood Calcium
  • Calcitonin (CT) from thyroid lowers blood calcium by adding it to bones
  • Parathyroid hormone from parathyroid glands (small pea-shaped gland embedded in back of thyroid) increases blood calcium by removing it from bones
adrenal glands
Adrenal Glands
  • Located on top of kidneys
  • Gross Anatomy
    • Enclosed by capsule
    • Outer cortex
    • Inner medulla
histology of adrenal glands
Histology of Adrenal Glands
  • Cortex with three zones
    • Secrete steroid hormones called corticoids
    • Outer (glomerular) zone
      • Cells in globular clusters
      • Secretes mineralocorticoids
    • Middle (fascicular) zone
      • Cells form vertical elongated bundles
      • Secrete glucocorticoids
histology of adrenal glands1
Histology of Adrenal Glands
  • Inner (reticular) zone
    • Cells form irregular, net-like pattern
    • Secrete some sex steroids in both sexes
    • More important in females
      • Affects female sex drive
      • Produces some estrogens
    • Secretion stimulated by ACTH
  • Mineralocorticoids: glomerular zone
    • Aldosterone most important
    • Regulates blood sodium, potassium and acid
    • Regulation affects fluid & electrolyte homeostasis
  • Glucocorticoids from fascicular zone
  • Principle one is cortisol
  • Actions include
    • Response to stress by
      • Glucose formation from fats and protein
      • Conversion of excess glucose to glycogen for storage in liver
      • use of fat for energy assures glucose availability for brain
  • Glucocorticoid actions
      • Reduce inflammation
      • Various steroids including cortisol, cortisone, and synthetic steroids used medically to reduce inflammation
  • Control is by negative feedback
imbalances of glucocorticoids
Imbalances of Glucocorticoids
  • Addison’s disease
    • Insufficient glucocorticoids
    • Lack of energy
    • Weight loss
    • Inability to resist stress
    • John F. Kennedy had it
imbalances of glucocorticoids1
Imbalances of Glucocorticoids
  • Cushing’s Disease
    • Excessive glucocorticoids
    • Muscle wasting
    • Fat redistribution
    • Spindly arms & legs
    • Large abdomen with stretch marks
    • Rounded face
    • Fatty hump between shoulders
addison s disease president kennedy
Addison’s Disease – President Kennedy

Before SteroidTreatment

During SteroidTreatment

adrenal medulla
Adrenal Medulla
  • Develop from same tissue as the sympathetic

nervous system

  • Chromaffin cells receive direct innervation from sympathetic nervous system
  • Sympathetic stimulation increases hormone secretion by adrenal medulla
  • Hormones are sympathomimetic
    • effects mimic those of sympathetic NS
    • cause fight-flight behavior
hormones of adrenal medulla
Hormones of Adrenal Medulla
  • Catecholamines
  • epinephrine and norepinephrine
  • (adrenaline & noradrenaline)
    • Targets – most cells
    • React quickly to stress by:
      • heart rate and strength
      • blood flow to skeletal muscles, heart and brain
      • Dilation of airways
      • fuel for energy
      • blood pressure
  • Large leaf-shaped gland
  • Located in the curve of small intestine and extend to the spleen
  • Both endocrine and exocrine
    • Endocrine part secretes hormones
    • Exocrine part secretes digestive enzymes
anatomy of pancreas
Anatomy of Pancreas
  • Five inches long, consists of head, body & tail
  • Most cells produce digestive enzymes
  • Endocrine cells in pancreatic islets produce hormones
cell organization in pancreas
Cell Organization in Pancreas
  • Exocrine acinar cells surround a small duct
  • Endocrine cells secrete near a capillary
histology of the pancreas
Histology of the Pancreas
  • 1 to 2 million pancreatic islets
  • Contains 4 types of endocrine cells
cell types in the pancreatic islets
Cell Types in the Pancreatic Islets
  • Alpha cells (20%) produce glucagon
  • Beta cells (70%) produce insulin
  • Delta cells (5%) produce somatostatin
  • PP cells (5%) produce pancreatic polypeptide
actions of insulin
Actions of Insulin
  • Insulin decreases blood glucose by:
    •  uptake of glucose into cells
    • synthesis of liver glycogen for storage
  • Insulin also protein & fat synthesis
actions of glucagon
Actions of Glucagon
  • Glucagon increases blood glucose by:
    • Synthesis of glucose from amino acids in the liver
    • breakdown of liver glycogen into glucose
    • release of glucose from liver into blood
regulation of glucagon insulin secretion
Regulation of Glucagon & Insulin Secretion
  • High blood glucose after a meal stimulates secretion of insulin and inhibits secretion of glucagon
  • Low blood glucose when fasting stimulates release of glucagon and inhibits secretion of insulin
diabetes mellitus
Diabetes Mellitus
  • Insulin is unavailable for uptake of glucose into the cells
  • Or the cells are not responding to insulin
  • Blood glucose levels becomes elevated – hyperglycemia
diabetes mellitus1
Diabetes Mellitus
  • Two Types:
    • Type I (IDDM) or juvenile DM
      • Beta cells destroyed by own immune system
      • Insulin levels low or absent.
      • Insulin injections required.
      • Usually develops in people younger than 20
diabetes mellitus2
Diabetes Mellitus
  • Type II (NIDDM) or maturity onset DM
    • Most common type (90%)
    • Insulin may still be secreted but cells may be less sensitive to its actions
    • Insulin injections may not be required
    • Mostly in people over 35 who are obese
    • May be controlled by diet
three signs p s of dm
Three Signs (P’s) of DM
  • Polyuria

- Excessive urination

  • Polydypsia

- Excessive water drinking

  • Polyphagia

- Excessive eating

complications of dm
Complications of DM
  • Cardivascular disease
  • Loss of vision
  • Kidney disease

- Most complications linked to high

glucose and acidosis

- Acidosis caused by excessive use of

fat for energy instead of glucose