DOC PREVIEW
Pitt NUR 0013 - Anatomy Endocrine System

This preview shows page 1-2 out of 6 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 6 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 6 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 6 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

NUR 0013 1st Edition Lecture 2 Outline of Last Lecture I. Principles of the endocrine system Outline of Current Lecture I. Membrane bound receptorsa. Amino acids, proteins, peptides b. Need a 2nd messenger (cAMP) to cross cell membraneII. Intracellular receptorsa. Lipid-soluble and Thyroid hormoneb. Can easily cross cell membranec. Activates gene replication directly III. Hormone target specifitya. 3DShape, number of receptors ectb. up regulation,c. down regulation IV. Half lifea. Steroids have long half lifeb. Amino acids, peptides, proteins have short half lifeV.VI. Regulation of Hormone Secretion - 3 major patternsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.VII. Major hormonesa. Anterior Pituitary – 6 total, 4 of them are tropicb. Posterior pituitary – ADH and Oxytocin Current LectureLecture 21. Membrane Bound and Intracellular Receptors Membrane bound receptors Hormones made of proteins, glycoproteins, and polypeptides, are water soluble or have too large a molecular weight to pass through the cell membrane so they must bind to receptors in the cell membrane. Note: All amino acid are water soluble EXCEPT thyroid hormone  This can cause the activation of 2 nd messenger molecules inside the cell which, have very specific functions Membrane bound receptors tend to create a cascade effect in which the activation of a 2nd messenger like cyclic AMP can effect many different types of enzymes at the same time.  E.g. of 2nd messengers – cAMP, cGMP, IP3, DAG Therefore, response tends to be fairly quick because the second messengers are just activating enzymes that are already present in the cell.Intracellular receptors Steroid based hormones pass easily through cell membranes into the cytoplasm. Some steroid based hormones bind to receptors in the cytoplasm and others diffuse directly into the nucleus to bind with receptors there. This binding causes mRNA to be produced and a new protein will be coded for in the cytoplasm. Often there is a latent period while the mRNA is being created and while the new proteins are being synthesized, so these types of hormones tend to have a slower response time because it takes longer to actually create a protein, rather than just activate one as do membrane bound receptors. (E, g, sex hormones). When a hormone-receptor complex stimulates mRNA this is called direct gene activation by a hormone. Remember : Thyroid hormone (an amino acid derivative) binds to intracellular receptorsE. Hormone-Target Specificity1. Hormone Receptors Are 3D shaped protein or glycoprotein receptors on the surface of the cells of the target tissues. Each receptor is specific to its own type of hormone.e.g. - square block in square hole/ circle block wont fit in square holee.g. – thyroid hormone will not bind to insulin receptors. Hormone-receptor interaction depends on1. blood levels of hormone2. relative number of receptors on target cells3. Affinity of the bond between the hormone and receptor.2. Down Regulation and Up Regulation of receptors Down regulation Occurs when a target cell has been exposed to a hormone for a prolonged period of time, causes fatigue of receptors on target tissue. That is why as you take certain med the amount you take goes down  UP Regulation Opposite of DR, and causes more receptors to be synthesized or to open up on the surface of the target cell. (positive feedback system)  Down and Up regulation occur most often in cells that are adapted periodic burst of hormones rather than long sustained amounts of hormone being released.F. Half-life, Metabolism and Excretion1. Hormones are most effective if they are released in periodic bursts and remain active for only a short period of time. Water soluble hormones proteins, peptides, Amino acids  short half-lives - degraded easily by enzymes and excreted. generally increase and decrease rapidly and have a short duration. Half-lives range from a few seconds to 30 minutes or so. Lipid based hormones lipids, steroids long half-lives - bind to plasma proteins which reduces the rate at which they diffuse through blood vessel walls.  Generally - remain nearly constant over longer periods of time, excreted at a much slower rate than other hormones.G. Integration of Hormone at Target Cells1. Permissiveness –when one hormone allows another to have an effecte.g. – TH influences the timing and development of the reproductive organs2. Synergism – when the combined effects of two hormones is amplifiede.g. – glucagon and epinephrine on liver.3. Antagonism – when one hormone opposes the activity of anothere.g. glucagon v. insulin.H. Regulation of Hormone Secretion - 3 major patterns1. Action of substance other than a hormone on the endocrine glandE.g. Effects of glucose on insulin secretion Action - insulin levels rise and fall based on glucose levels in blood2. Neural control of the endocrine glandE.g. effects of sympathetic nervous system on adrenal gland action - Stress or sensory input can influence whether a nerve will have an excitatory or inhibitory effect on hormone secretion. 3. Control of an endocrine gland’s secretion by secretions of hormones or neurohormones of another endocrine gland – hormonal secretion e.g. control of most endocrine glands by the anterior pituitary and hypothalamus. hypothalamus anterior pituitary other endocrine glands. this pattern can work in either a negative or positive feed back cycleII. Major Endocrine Glands and Their Associated HormonesPituitaryA. Pituitary gland (a.k.a Hypophysis)1. Located in the sella turcica (Turkish saddle) of the sphenoid bone.2. Connected to the hypothalamus via the infundibulum3. The hypothalamus releases a variety of hormones that impact both the anterior and posterior pituitary.Neurohypophysis (posterior pituitary) - nervous tissue The posterior pituitary does not secrete any hormones because it primarily neurons. Axons from the hypothalamus terminate here and their chemical products are stored until needed. The nerve tracts (axons) that connect the hypothalamus to the posteriorpituitary through the infundibulum are called the hypothalamohypophyseal tract. Supraoptic and paraventricular hypothalamus secretes – ADH and Oxytocin respectively. These hormones are also referred as


View Full Document

Pitt NUR 0013 - Anatomy Endocrine System

Download Anatomy Endocrine System
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Anatomy Endocrine System and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Anatomy Endocrine System 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?