Lab 9: Endocrine System

Review

• Where does pepsinogen come from?

• Why doesn’t the stomach digest itself?

• Why can Veggans not eat meat anymore?

Function

• Maintain Homeostasis (Balance)– Communicates and coordinates physiological

responses

• Example of Imbalance?

DVD clipBattling A Giant

Hormones

• Chemical messengers– Stimulate physiological responses in other cells– Target Cells

• Tropic (Trophic) Hormones– Hormone whose target is another endocrine

gland.

• How do hormones travel?

Hormone Production and Distribution

• Production– Endocrine Glands– Gland: an organ specialized to produce

secretions

• Distribution– Relies on blood circulatory system

• How does this compare to nervous system?

Endocrine Glands

• Hypothalamus• Pituitary• Thyroid• Parathyroid• Pancreas• Adrenal• Gonads

Hypothalamus• Location- Base of brain

case• Functions- Regulation

of Primitive or Basal activities such as sex drive and water balance

• 9 hormones-– 7 act on anterior lobe of

pituitary gland (Tropic)– 2 stored in posterior

lobe

Hypothalamo-hypophyseal portal system

• What type of vessels comprise a portal system?

• What is unique about a portal system?

Hypothalamo-hypophyseal portal system and tract

• Location-– Pituitary Stalk

(Infundibulum)• Link the hypothalmus

to the pituitary gland• Portal- Capillary beds

connect to anterior lobe

• Tract- Neurons connect to posterior lobe

Pituitary gland• Location- Sphenoid

bone of the skull• Anterior Lobe

– Produces Six hormones that Regulate

• Reproduction• Growth• Activity of the

Thyroid Gland

• Posterior Lobe– No hormone production

only storage of hypothalamic hormones

Thyroid

• Largest endocrine gland

• Location- Wrapped around anterior and lateral sides of Trachea, just below Larynx

• Hormone- Thyroid Hormone• Function- Increases Metabolic

Rate

Parathroid Glands

• Location- Four glands imbedded on posterior surface of Thyroid

• Hormone- Parathyroid Hormone

• Function- Calcium Regulation

Adrenal Glands

• Cortex– Zona Glomerulosa:

Outer layer– Zona Fasciculata:

Middle Layer– Zona Reticularis-

Inner Layer

• Medulla

• Location- 2 glands one

superior to each Kidney.

Adrenal Glands

• Cortex- – Zona Glomerulosa

• Mineralocorticoids- Regulate Kidney Na+ and K+ excretion

– Zona Fasiculata • Glucocorticoids- Stress

and immune supression

– Zona Reticulata-• Sex steroids- androgens

precursor to sex hormones

• Medulla- (Fight or Flight Response) Epinepherine and Norepinephrine

Pancreas• Location- Inferior

and posterior to Stomach

• Pancreatic Islets– Clusters of

endocrine cells

• Function- Glucose Regulation

Gonads

• Male- Testes– Secrete Androgens such as Testosterone

• Female- Ovary– Secrete Estrogen and Progesterone

DNH- Anatomy

Homeostatic Control

• Metabolic Rate

• Growth Hormone

• Blood Glucose Levels

• Blood Calcium Levels

• Water Retention

• Stress

Metabolic RateGland Hormones

Hypothalamus Thyrotropin Releasing Hormone (TRH)

Pituitary Gland Thyroid Stimulatory Hormone (TSH)

Thyroid Thyroxine (T4) and Triiodothyronine (T3)

Interactions between Metabolic Hormones

T4 & T3

Metabolic Rate

• Hormones released in response to a decrease in T3 blood levels

• Affects: All cells in the body except brain, spleen, testes, uterus and the thyroid gland

• Results: Increase in basal metabolic rate, oxygen consumption and heat production

Disorders

• Hypothyroidism (Creatinism)– Children: mental

retardation, development abnormalities

– Adults: lethargy, obesity

• Goiter

• Hyperthyroidism (Graves’ Disease)– Weight loss, sweating,

nervousness, sleeplessness

• Goiter -----a hypertrophy of the

thyroid gland resulting from iodine deficiency

Growth• Gland- Pituitary Gland• Hormone-

– Growth Hormone: increases mitosis and cellular differentiation.

– Secreted in response to Sleep, Trauma, Exercise, High protein meals, and Low blood sugar

• Effects– Directly: Liver – Indirectly: Bone, Muscle, and Cartilage

Disorders• Pituitary Dwarfism-

Insufficient secretion of Growth Hormone

• Gigantism- Over-secretion of Growth Hormone

Blood Glucose Levels• Gland- Pancreas• Hormones

– Insulin- increases uptake of glucose by cells– Glucagon- increases release of glucose by cells

and increases liver glucose production• Released in response to…

– Insulin: high blood glucose levels– Glucagon: low blood glucose levels

• Effects-– Systemic– Liver

Disorders• Diabetes Mellitus- Disruption of Metabolism due

to lack of insulin or lack of response to insulin.

• Symptoms- Excessive Urine, Intense Thirst, and Ravenous Hunger

• Type I- (Juvenile of Insulin Dependant) Destruction of Insulin Producing Cells

• Type II- (Adult or Noninsulin Dependant) Target cells resistant to Insulin

Blood Calcium Levels

• Gland- Parathyroid

• Hormone- Parathyroid hormone– Released in response to low calcium levels

• Effects – Kidneys- Retain Calcium– Bones- Release Calcium

Disorders

• Hyper- or Hypo-parathyroidism– Hyper-parathyroidism: Over Secretion

• Soft, Fragile Bones • Kidney stones

– Hypo-parathyroidism: Under Secretion• Rapid Decline of Blood Calcium

• Fatal

Water Retention

• Gland- Hypothalamus– Stored and released by posterior pituitary

• Hormone- ADH– Released in response to Dehydration and High

Osmolarity (thickening) of blood

• Effects?

Disorders????

Stress

• Gland- Adrenal Cortex

• Hormones– Glucocorticoids

• Effect- Systemic

Disorders

• Cushing Syndrome– Cause: Excess

Glucocorticoids– Disrupts Protein and Fat

Metabolism– Symptom is abnormal fat

deposits, fatigue and exhaustion

Cushing Syndrome (cont.)After Surgery

Dissection & Review

• Cat Questions- – You won’t need to find the specific glands

– You will need to know region of the body where found

– You will need to know location of organs affected

• Lab Notes at Library on Reserve• Research Papers Next Week Due• Reviews for final exam will be in Two Weeks.