Bio 231 @ Oit - Lecture 9

Front 1

Describe hormone activity for GH

Back 1

- Will cause all body cells to increase in size and divide (mitosis)
- Primary target is bone and muscle tissue
- Increases protein syntehsis necessary for collegen fibers within the epiphyseal plate of the long bones and the contractile proteins of the myofibrils in muscle tissue.
- Hypersecretion results in giganticism or acromegaly following the closure of growth plates.
-Hyposecretion results in pituitary dwarfism

Front 2

Describe hormone activity for TSH and ACTH

Back 2

- Thyroid stimulating hormone responsible for normal development and functino of thyroid gland.
- Adrenocorticotropic (ACTH) stimulates the activity of the adrenal cortex of the adrenal gland. Triggers the release of glucocorticoids and mineralocorticoids.

Front 3

Describe the function of the posterior pituitary gland

Back 3

- Antidiuretic Hormone (ADH)
- Oxytocin (OT)
- The hypothalamus contains the neural-secretory cells, the synthesis and release of two hormones.
- Hormones sythesized within hypothalamus and trasported along axons to be stored in axon terminals.
- the _supraoptic nucleus_ for ADH and the _paraventricular nucleus_ for oxytocin

Front 4

Describe the function of the adrenal gland (adrenal cortex)

Back 4

- Arranged in three distinct cellular zones: zona glomerulosa, zona fasciculata, and zona reticularis
- Two major classes of hormones:
-- _mineralocorticoid_ (aldosterone) increase the reabsorption of sodium and water (glomerulosa)
-- _glucocorticoid_ maintain high glucose levels, suppresses the inflammatory response and inhibits the immune system (fasciculata & reticularis).

Front 5

Describe the operation of the adrenal gland (adrenal medula)

Back 5

- The cells of the adrenal medulla are postganglionic neurons of the sympathetic divison of ANS.
- Secretes two hormones epinephrine and norepinephrine "fight or flight" response
- Hormone action:
-- Blood glucose levels rise (liver converts glycogen to glucose)
-- Blood vessels constrict
-- Heart rate increases
-- Bronchial tubes dilate
-- Reduced blood flow to non-essential organs

Front 6

Describe the operation of the Thyroid Gland

Back 6

- Located on the trachea, below the larynx
- The gland is composed of hollow spherical structures called follicles
- Follicular cells form the spherical follicles, fille with colloid (jelly-like) precursor to thyroid hormone (TH)
- Thyroid hormone affects nearly every cell in the body. As a steriod hormone binds to the gener and initiates protein synthesis
- Functions include:
-- Increasing metabolic rate and heat production
-- Glucose oxidation (usage)
-- Necessary for normal tissue growth and development
- The parafollicular cells which surround each thyroid follicle secrete the hormone calcitonin (lowers blood Ca++ levels)
- Calcitonin targets bone and:
-- Inhibits osteoclast activity
-- Stimulates Ca++ uptake from blood and increases matrix formation

Front 7

Describe the operation of the Parathyroid Gland

Back 7

- Located on the posterior surface of the thyroid gland
- Major cell type is the cheif cell which secretes parathyroid hormone (PTH)
- PTH increases blood calcium lelvels by:
-- Increasing osteoclast activity
-- Decreasing secretion of calcium from kidney
-- Increasing intestinal absorption of dietary calcium

Front 8

Describe the operation of the Pancreas

Back 8

- Is a "mixed" gland, provides both endocrine and exocrine functions.
- The endocrine cells are located in clusters called "The Islets of Langerhans"
- Two major cell types
-- Alpha cells secrete glucagon
-- Beta cells secrete insulin

Front 9

How is Glucagon utilized by the body?

Back 9

- The primary target tissue is the liver
-- Initiates the breakdown of glycogen to glucose (glycogenolysis)
-- Synthesis of glucose from lactic acid (gluconeogeneis)
-- Releases glucose to the blood, causing blood glucose levels to rise
- Falling or low blood glucose levels stimulates glucagon release.
- Elevated blood glucose levels inhibit (negative feed-back) release.

Front 10

How is Insulin utilized by the body?

Back 10

- Primary function is to lower blood glucose levels.
-- Insulin will increase membrane transport of glucose in to body cells, especially muscle and fat cells
-- Insulin inhibits the breakdown of glycogen to glucose
-- Inhibits the conversion of amino acids and fats into glucose
- Insulin removes glucose from the blood, which is ten converted to glycogen or fats, ATP production, and alos promotes protein synthesis (stimulates amino acid uptake)