Cardiac Hormones, Diseases Flashcards
Where does Epi/NE come from/do?
Adrenal Medulla
Opens Ca++ channels, ↑contractability
↑ HR
Where does ADH come from/go/do
Post. Pituitary
Kidneys, retain H20
↑ BP
Where does aldosterone come from/go/do?
Zona Glomerulosa, Adrenal Cortex
↑ Na+ retention
↑ BP
What is the first precursor for angiotensin II? Where is it produced?
Angiotensinogen in blood is produced by the liver
What and how does Angiotensinogen change to?
Changed to angiotensin I by renin
How is angiotensin II created from angiotensin I?
Changed to angiotensin II in lung tissue by ACE (angiotensin converting enzyme)
What are the 4 effects of angiotensin II?
Causes widespread arteriolar vasoconstriction
Activate thirst centers in hypothalamus
Stimulate aldosterone release
Stimulate ADH release
What two extracellular ions impact cardiac function?
The relative combinations of K+ and Ca2+ have a large impact on cardiac function
What is the term for something than changes HR?
Chronotropic
What does a positive chronotropic agent do?
Increase HR
What are 5 positive chronotropic agents?
Sympathetic Nervous System
Nicotine
Caffeine
Epi/NE (nb. stimulate SNS)
What does a negative chronotropic agent do?
Lower HR
What are two negative chronotropic agents?
PNS- Parasympathetic nervous system
Hyperkalemia
What is hyperkalemia?
High potassium- K+ diffuses in,making the membrane potential less negative, this interferes with myocyte repolarization, myocardium becomes less excitable, HR slows and becomes irregular
What is the term for something that changes contractibility?
Inotropic
What do positive and negative inotropic agents do?
Increase contractibility
Decrease contractibility
What are 5 positive inotropic agents?
SNS EPI/NE Caffeine Digitalis- Foxglove plant Hypercalcemia
What are some effects of hypercalcemia?
Ca++ is good, but don’t want too much Ca++, it diffuses into myocytes and contractions are too strong/protracted → cardiac arrest in systole
What are three negative inotropic agents?
PNS
Myocardial hypoxia
Hypocalcemia
What are some effects of hypocalcemia?
Myocytes lose Ca++ to ECF → weak, irregular HB
What is tachycardia?
What is bradycardia?
Persistent resting HR above 100 BPM
Persistent resting HR below 60 BPM
What is circulatory shock?
When there is inadequate blood flow, or when cardiac output is insufficient to meet the body’s metabolic needs
What are two kinds of circulatory shock?
Hypovolemic shock
Anaphylactic shock
What is hypovolemic shock, and what can cause it?
Loss of blood volume
Due to: hemorrhage, trauma, dehydration, burns,bleeding ulcers
What are the sx of hypovolemic shock, and what can it lead to?
Sx: Tachycardia; vasoconstriction in skin, GI, kidney, and muscles
Leads to ↓BP and ↓cardiac output
What is the end result of hypovolemic shock?
↓BP; tachycardia; cold, clammy skin; little untine → body diverts blood to brain/heart at the expense of other systems
What is anaphylactic shock and what causes it?
Loss of blood volume
Due to: Immediate and severe allergic rxn to antigen eg bee sting, penicillin
At a cellular level, what happens in anaphylaxis? What is the end result?
Will have: Widespread release of histamine (basophils/mast cells)
End result: Widespread vasodilation, bronchoconstriction, circulatory shock, death
What is CHF?
When cardiac output is insufficient to maintain the required blood flow of the body.
What causes CHF?
Caused by MI, Valve defects, chronic hypertension (↑BP)
What is a tx for CHF?
Digitalis, a cardiac stimulant from fox glove plant
What is COPD?
Chronic obstructive pulmonary disease- Any disorder in which there is a long-term obstruction of airflow and a substantial reduction in pulmonary ventilation,
What condition can come from COPD?
cor pulmonale
What is cor pulmonale?
hypertrophy and potential right heart failure due to obstructed pulmonary circuit
