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Endrocrine System
Lecture Exam 3
34
Physiology
Undergraduate 1
03/11/2011

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Term

What are endocrine glands?

 

List examples

Definition

ductless glands that release hormones into the blood stream

 

pituitary gland, thyroid gland, adrenal glands

Term
Are hormones secreting cells endocrine glands?
Definition
no
Term
Antagonistic Effects
Definition

When the action of one hormone is inhibited by another hormone

 

ex. Insulin stimulates glucose uptake.

Glucagon stimulates glycogen breakdown (glucose release)

Term
Permissive Effect
Definition

When the action of one hormone enhances the responsiveness of the target organ to a second hormone.

 

ex. Estrogen induces formation of receptors of progeseterone.

Term
Hormone Half-Life
Definition

-the time required for the plasma concentration of a given hormone to be reduced to half of its level 

-ranges from minutes to hours to days

Term
How are hormones removed?
Definition

-do not accumulate in the blood 

-removed rapidly by their target organ and the liver

Term
Pharmacological Concentration
Definition
A concentration of the hormone which is higher than normal as when taken as a drug; effects may be different than those produced by physiological concentrations
Term
Physiological Concentration
Definition
the normal concentration range of the hormone in the body which produces normal tissue responses
Term
What does the concentration of the hormone in the blood reflect?
Definition
the rate of the hormone's secretion by the gland
Term
How does a prohormone become active?
Definition
A piece of the longer chain is removed from the prohormone to form the active version
Term
Prohormone
Definition
the inactive form of a hormone
Term
What is the classification of hormones based on?
Definition
Chemical Structure
Term
Receptor
Definition

a protein molecule that binds with a hormone in a complementary fashion (lock and key); target cells have receptors that recognize and bind with a specific hormone

 

-target cells have 2,000- 100,000 receptors for a specific hormone

Term
Target Cells
Definition

Tissue cells which are influenced by the binding of a specific hormone to a receptor

 

ex. Insulin hormones bind to receptors on liver cells

Term
Hormone
Definition

-a molecule that is either a steroid based, or an amino acid based molecule

-secreted by endocrine glands and cells of various glands

-travel in blood stream to target cell where it acts as a chemical messenger to regulate specific body functions

Term
2 Mechanisms of Hormone Receptor Binding
Definition

1. Direct Gene Activation

2. Second Messenger System

Term
Synergistic Effects
Definition

When 2 or more hormones work together to produce an additive response

 

ex. NE and E together produce an increase in cardiac rate

Term
What is a target tissue responsive to?
Definition

1. Concentration of a hormone

2. Effects of other hormones

Term
Major Processes Controlled by Hormones
Definition

1. Reproduction

2. Growth and Development

3. Mobilization of Body Defenses against Stressors

4. Maintenance of Electrolytes, Water, and Nutrienet Balance of the Blood

5. Regulation of Cellular Metabolism and Energy Balance

Term
Second Messenger System
Definition

1. Hormone binds to receptor on plasma membrane.

2. Formation of 2nd messenger molecule within cell that activates specific enzymes 

3. Enzymes catalyze reaction

 

Typical of amino acid based molecules

Term
Direct Gene Activation
Definition

1. Hormone enters cell and binds to receptor in the nucleus

2. Binds to DNA which leads to the formation of specific proteins

3. New proteins alter cell's activity

 

Typical of a steroid based molecule

Term
Control of Hormone Secretions
Definition

1. Negative Feedback System- reverses the original stimulus

2. Positive Feedback System- effects stimulate more effects

Term
What serves as the link between the nervous system and the endocrine system?
Definition
Hypothalamus
Term
Different Kinds of Hormones
Definition

1. Amines

2. Polypeptides and Proteins 

3. Glycoproteins

4. Steroids

Term
How is the pituitary gland connected to the hypothalamus?
Definition
Infundibulum (anterior and posterior lobes)
Term
Hypothalamic-Pituitary Portal System
Definition

Hypothalamus and Anterior Lobe Vascular Connection

 

Hormones in hypothalamus --> capillary bed --> portal vein

 

anterior lobe (capillary bed)

Term
Hypothalamic- Pituitary Tract System
Definition

Hypothalamus and Posterior Lobe- Neural Connection

 

Hormones in Hypothalamus --> posterior lobe via neuron axon

 

stored and released later

Term

Gonatropin Releasing Hormone

GnRH

Definition
Stimulates anterior lobe to secrete Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH)
Term

Thyroid Releasing Hormone

TRH

Definition
Stimulates anterior lobe to secrete TSH (Thyroid Stimulating Hormone)
Term

Prolactin Releasing Hormone

PRH

Definition
Stimulates anterior lobe to secrete Prolactin (PRL)
Term

Growth Hormone Releasing Hormone

GHRH

Definition
Stimulates anterior lobe to secrete Growth Hormone (GH)
Term

Corticotrophin Releasing Hormone 

CRH

Definition
Stimulates Anterior Lobe to Secrete Adrenocorticotropic Hormone (ACTH)
Term

Prolactin Inhibiting Hormone

PIH

Definition
Inhibits Prolactin (PRL) secretion from anterior lobe
Term

Growth Hormone Inhibiting Hormone

GHIH/ Somatostatin

Definition
Inhibits Growth Hormone (GH) secretion from anterior lobe
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