{"id":393,"date":"2015-08-11T17:10:05","date_gmt":"2015-08-11T17:10:05","guid":{"rendered":"http:\/\/sites.msudenver.edu\/haysc\/?page_id=393"},"modified":"2025-09-30T16:27:53","modified_gmt":"2025-09-30T16:27:53","slug":"outline-1-bio-2320-endocrine-system","status":"publish","type":"page","link":"https:\/\/sites.msudenver.edu\/haysc\/biology-courses\/human-anatomy-and-physiology-ii-homepage-bio-2320\/outline-1-bio-2320-endocrine-system\/","title":{"rendered":"Outline-1, BIO 2320, Endocrine System"},"content":{"rendered":"

IV. Endocrine System<\/strong><\/p>\n

A. Overall functions<\/p>\n

1. Regulatory System<\/p>\n

2. Maintains homeostasis internally<\/p>\n

3. Responds to help cope with environmental changes<\/p>\n

4. Growth & development<\/p>\n

5. Reproduction<\/p>\n

B. Exocrine\u00a0<\/strong>vs\u00a0Endocrine<\/strong>\u00a0glands<\/p>\n

Exocrine releases contents into ducts or skin surface, endocrine glands are ductless and release contents into blood<\/em><\/p>\n

C. Hormone<\/strong><\/p>\n

1. Definition –\u00a0Chemical messenger carried by bloodstream, made by endocrine glands<\/em><\/p>\n

2. Structure<\/p>\n

Organic, amino acids, cholesterol derivatives<\/em><\/p>\n

3. Transport<\/p>\n

Many are bound to specific carrier proteins<\/em><\/p>\n

4. Action<\/p>\n

a. Target cell<\/p>\n

b. Receptors<\/p>\n

1. Plasma membrane<\/p>\n

2. Within target cell<\/p>\n

c. Second messenger cAMP<\/p>\n

1. Stimulatory<\/p>\n

2. Inhibitory<\/p>\n

d. Activation of genes<\/p>\n

5. Hormonal interrelationships<\/p>\n

6. N.S. & Endocrine relationships<\/p>\n

D. Controls<\/p>\n

1. Negative feedback<\/p>\n

2. Releasing or inhibiting hormones- Hypothalamus<\/p>\n

E. Pituitary Gland {Hypophysis}<\/strong><\/p>\n

1. Location<\/p>\n

Sella turcica of sphenoid bone<\/em><\/p>\n

2. Adenohypophysis<\/strong><\/p>\n

Anterior lobe of pituitary gland<\/em><\/p>\n

a. Gonadotropins<\/strong><\/p>\n

–\u00a0Stimulates gonads<\/em><\/p>\n

–FSH\u00a0– Follicle stimulating hormone<\/em><\/strong>, stimulates follicle development in ovaries, stimulates sperm production and maturation in male<\/em><\/p>\n

–LH \/ ICSH<\/strong>\u00a0Luteinizing hormone<\/em><\/strong>\u00a0results in ovulation in female,\u00a0Interstitial cell stimulating hormone<\/strong>\u00a0results in testosterone production in male<\/em><\/p>\n

b. TSH\u00a0-Thyroid stimulating hormone<\/em><\/strong><\/p>\n

c. ACTH\u00a0-Adrenocorticotropic hormone<\/em><\/strong><\/p>\n

d. GH\u00a0-Growth hormone<\/em><\/strong><\/p>\n

e. Prolactin<\/strong>–\u00a0Initiates and maintains milk production in female<\/em><\/p>\n

f. MSH\u00a0– Melanocyte stimulating hormone<\/em><\/strong>stimulates skin melanin (pigment)<\/em><\/p>\n

g. Endorphins –\u00a0Peptides made by Adenohypophysis in addition to the hormones that has opiate-like effects<\/em><\/p>\n

3. Controls<\/p>\n

a. Inhibiting\/releasing hormones (GnRH\u00a0Gondadotropin releasing hormone<\/em>, TRH\u00a0Thyrotropin releasing hormone<\/em>, PIF\u00a0Prolactin inhibiting factor<\/em>, CRF\u00a0Corticotropin releasing factor<\/em>, Somatostatin\u00a0Growth hormone inhibiting hormone<\/em>)<\/p>\n

b. Brain (Emotions)<\/p>\n

c. Feedback<\/p>\n

Negative feedback mechanisms prevail<\/em><\/p>\n

4. Neurohypophysis<\/strong><\/p>\n

Posterior lobe of pituitary gland<\/em><\/p>\n

a. Infundibulum (Hypothalamic-hypophyseal tract)<\/p>\n

b. ADH (vasopressin)\u00a0– Antidiuretic hormone\u00a0<\/em><\/strong>causes water reabsorption from kidney to bloodstream<\/em><\/p>\n

c. Oxytocin<\/strong><\/p>\n

Uterine contractions for childbirth and milk letdown<\/em><\/p>\n

F.\u00a0Thyroid Gland<\/strong><\/p>\n

1. Location<\/p>\n

Inferior larynx<\/em><\/p>\n

2. Histology (follicle cells, colloid)<\/p>\n

3. Thyroid hormones<\/p>\n

a. Iodine<\/p>\n

b. T4\u00a0<\/strong>(thyroxine) 90%<\/p>\n

c. T3<\/strong>(triiodothyronine) 10%<\/p>\n

d. TBG\u00a0– Most thyroid hormones are carried in plasma bound to thyroid binding globulin<\/em><\/p>\n

e. Regulates metabolic rate<\/p>\n

f. Controls<\/p>\n

TSH, TRH, negative feedback<\/em><\/p>\n

4. Calcitonin<\/strong><\/p>\n

a. Parafollicular = C cells<\/p>\n

b. Decreases Ca & P<\/p>\n

c. Controls<\/p>\n

If blood calcium levels are high, Calcitonin is secreted<\/em><\/p>\n

G. Parathyroid glands<\/strong><\/p>\n

1. Location<\/p>\n

4 – embedded in posterior surface of thyroid gland<\/em><\/p>\n

2. PTH (=Parathormone)<\/strong>function (increases Ca; decreases P)<\/p>\n

3. Controls<\/p>\n

If blood calcium levels are low, PTH is secreted<\/em><\/p>\n

H. Adrenal gland<\/strong><\/p>\n

1. Location<\/p>\n

Superior to kidney<\/em><\/p>\n

2. Adrenal medulla –\u00a0Inner portion<\/em><\/strong><\/p>\n

a. Chromaffin cells<\/p>\n

b. Epinephrine<\/strong>(80%),\u00a0Norepinephrine<\/strong>\u00a0(20%)<\/p>\n

c. Action (glucose, ht, bl. vessels, bl. pressure, airways)<\/p>\n

d. Release (Pregang. neurons, excitement, injury)<\/p>\n

3. Adrenal cortex –\u00a0Outer portion<\/em><\/strong><\/p>\n

a. Mineralocorticoids<\/strong><\/p>\n

1. Zona glomerulosa –\u00a0Outermost layer<\/em><\/p>\n

2. Aldosterone<\/strong>(90%)<\/p>\n

3. Na reabsorption, K excretion –\u00a0In kidneys<\/em><\/p>\n

4. Release\/controls<\/p>\n

a. Renin\/Angiotensinogen<\/strong><\/p>\n

Renin is an enzyme made by the kidneys in response to low blood pressure. It causes inactive angiotensinogen to activate into Angiotensin, which stimulates Aldosterone release.<\/em><\/p>\n

b. High K, Low Na<\/p>\n

c. ACTH, CRH<\/p>\n

b. Glucocorticoids<\/strong><\/p>\n

1. Zona fasciculata\u00a0– Very thick middle layer<\/em><\/p>\n

2. Conserves & supplements energy<\/p>\n

3. Anti-inflammatory<\/p>\n

4. Release\/controls<\/p>\n

a. ACTH, CRH<\/p>\n

b. Stress<\/p>\n

c. Sex hormones<\/strong><\/p>\n

1. Zona reticularis –\u00a0Innermost layer<\/em><\/p>\n

I. Pancreas<\/strong><\/p>\n

1. Location<\/p>\n

Behind stomach and along duodenum (first part of small intestine)<\/em><\/p>\n

2. Exocrine & endocrine<\/p>\n

3. Pancreatic islets (of Langerhans) –\u00a0ENDOCRINE portion<\/em><\/p>\n

4. Insulin<\/strong>(beta cells, lowers blood glucose)<\/p>\n

5. Glucagon<\/strong>(alpha cells, raises blood glucose)<\/p>\n

6. Somatostatin<\/strong>(delta cells, inhibits growth hormone release)<\/p>\n

7. Release\/Controls<\/p>\n

a. Blood glucose level<\/p>\n

b. GI hormones – meals\/between meals<\/p>\n

c. ANS<\/p>\n

J. Gonads<\/strong><\/p>\n

Testes make androgens to be discussed later, Ovaries make estrogens and progesterones to be discussed later.<\/em><\/p>\n

K. Pineal gland<\/strong><\/p>\n

1. Location<\/p>\n

Roof of third ventricle in brain<\/em><\/p>\n

2. Melatonin <\/strong>Helps regulate circadian rhythms including sleep. Darkness stimulates melatonin release naturally.\u00a0 <\/em>( Melatonin inhibits gonadotropin-releasing hormone from hypothalamus in humans, thus inhibiting some reproductive functions. In animals that breed in springtime, as daylight increases, melatonin decreases.\u00a0 Therefore the inhibitory actions of reproduction stops and animals can breed.)<\/p>\n

L. Thymus<\/strong><\/p>\n

1. Location<\/p>\n

Within mediastinum above heart<\/em><\/p>\n

2. Puberty<\/p>\n

Decreases in size as we mature<\/em><\/p>\n

3. Immunity<\/p>\n

Thymic hormone<\/em><\/strong>\u00a0stimulates T cells after they leave the thymus<\/em><\/p>\n

M. Prostaglandins<\/strong><\/p>\n

1. Fatty acids<\/p>\n

2. Localized<\/p>\n

3. Functions vary<\/p>\n

Useful Videos:<\/p>\n

Crash Course A&P Endocrine System Part 1<\/a><\/p>\n

Crash Course A&P Endocrine System Part 2<\/a><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

IV. Endocrine System A. Overall functions 1. Regulatory System 2. Maintains homeostasis internally 3. Responds to help cope with environmental changes 4. Growth & development 5. Reproduction B. Exocrine\u00a0vs\u00a0Endocrine\u00a0glands Exocrine releases contents into ducts or skin surface, endocrine glands are … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":270,"featured_media":0,"parent":209,"menu_order":0,"comment_status":"closed","ping_status":"open","template":"","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"class_list":["post-393","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages\/393","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/users\/270"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/comments?post=393"}],"version-history":[{"count":0,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages\/393\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages\/209"}],"wp:attachment":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/media?parent=393"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}